WO2014037744A2

WO2014037744A2 - Rotary fluid transfer apparatus and associated methods

Info

Publication number: WO2014037744A2
Application number: PCT/GB2013/052353
Authority: WO
Inventors: Hugh Edward Fisher
Original assignee: Hugh Edward Fisher
Priority date: 2012-09-07
Filing date: 2013-09-09
Publication date: 2014-03-13
Also published as: US20180363648A1; WO2014037744A3; GB201504063D0; CA2884007A1; MX2015002927A; WO2014037748A2; CO7400887A2; CN108131290A; EP2893133A2; GB2524658B; WO2014037748A3; US20150233374A1; CN104718343A; EA201590238A1; GB2524658A; BR112015005065A2; GB201216036D0

Abstract

A fluid transfer device (10, 110, 210, 310, 410) and corresponding method of transferring fluid. The device (10, 110, 210, 310, 410) comprises a cam track (12, 112, 212, 312, 412) with a first cam track wall means (16, 116, 216, 316, 416) and a cam follower (14, 114, 214,314, 414) with a first cam follower wall means (18, 118, 218, 318, 418). At least one of the first cam track wall means and/or the first cam follower wall means (16, 116, 216, 316, 416, 18, 118, 218, 318, 418) comprises or provides a wave or waveform (30, 32, 130, 132, 230, 232, 330, 332, 430, 432). The first cam track wall means (16, 116, 216, 316, 416) and first cam follower wall means (18, 118, 218, 318, 418) face one another. At least one fluid chamber (20, 120, 220, 320, 420) is disposed between the cam track (12, 112, 212, 312, 412) and the cam follower (14, 14, 214,314, 414) and there is provided at least one fluid inlet (22, 122, 222, 322, 422) to the chamber and at least one fluid outlet (24, 124, 224, 324, 424) from the chamber (14, 114, 214,314, 414).

Description

ROTARY FLUID TRANSFER APPARATUS AND ASSOCIATED METHODS

TECHNICAL FIELD

The present invention relates to rotary fluid transfer apparatus and to associated methods. In particular, but not exclusively, the invention relates to fluid pumps or motors, such as for downhole use, and engines.

BACKGROUND

Different types of fluid transfer apparatus are known. For example various pumps are known for transferring fluid from one place to another. For example, in the recovery of fluids from formations, such as in the oil and gas industry, downhole pumps may be used to assist in the transfer of fluid to surface (e.g. where downhole hydrostatic pressure is insufficient to propel the oil or gas to surface).

Chambers are used to allow the appropriate pressurisation or depressurisation of fluids. Often pistons are used to vary pressure in the fluid chambers, or to provide a mechanical output such as an axial movement in response to a variation in pressure in the chamber. For example, known pumps use a piston to convert axial mechanical movement into the pressurisation of a fluid to force a fluid out of a fluid chamber. Similarly, a combustion engine uses an increase in pressure caused by the oxidation of a fuel to force a piston up or down.

The pumps, motors or engines often have valves or controlled ports to control the timing of fluid input or output to and from the chambers. The valves can be one-way valves to restrict the direction of flow.

In some applications, such as in downhole operations for recovering fluids, such as hydrocarbons, from underground formations, pumps and motors are required to operate remotely at sometimes great distances, often under challenging conditions, such as high temperatures and pressures. Failures or uncertainty of operation of pumps, motors or engines can lead to time-consuming and costly delays and potentially dangerous situations. For example, a failure of a downhole motor can require a retrieval of a tool from several kilometres depth, delaying operations by several hours at great expense. Pumps, motors and engines are often complex or expensive in an attempt to ensure reliability.

This background serves to set a scene to allow a skilled reader to better appreciate the following description. Therefore, none of the above discussion should necessarily be taken as an acknowledgement that that discussion is part of the state of the art or is common general knowledge.

It is an object of at least one embodiment of at least one aspect of the present invention to seek to obviate or at least mitigate one or more problems and/or disadvantages of the prior art.

SUM MARY

According to a first aspect of the invention there is provided a fluid transfer device comprising:

a cam track and a cam follower, wherein the cam track comprises a first cam track wall means, the cam follower comprises a first cam follower wall means, and the first cam track wall means and first cam follower wall means face one another;

at least one fluid chamber disposed between the cam track and the cam follower;

a fluid inlet to the at least one fluid chamber; and

a fluid outlet from the at least one fluid chamber.

At least one of the first cam track wall means and/or the first cam follower wall means may comprise or provide a wave or waveform.

The first cam follower wall means may comprise or provide a first cam follower wave or waveform. Additionally, or alternatively, the first cam track wall means may comprise or provide a first cam track wave or waveform.

The/each (respective) waves or waveforms may be substantially the same. For example, the first cam track wave or waveform may be of substantially similar shape, amplitude and frequency to the first cam follower wave or waveform.

Alternatively, the/each waves or waveforms may be substantially different. For example, the first cam track wave or waveform may comprise a different amplitude from the first cam follower wave or waveform.

The cam track and/or the cam follower may be coaxially arranged. The cam track and/or the cam follower may be configured to rotate about a central axis. The cam track may define a rotational path for the cam follower. The cam track may define a rotational path about the central axis.

A first axial member may comprise and/or define the cam track.

A second axial member may comprise and/or define the cam follower.

A volume of the at least one fluid chamber may correspond to a rotational position of the cam follower relative to the cam track. A volume of the at least one fluid chamber may correspond to an axial position of the cam follower relative to the cam track. The axial position may comprise an axial separation. The device may comprise a rotor. The cam follower may comprise a rotor. The cam follower may comprise a piston head. The device may comprise a stator. The cam track may comprise a stator. The cam track may comprise a cylinder.

The device may comprise a pump. A volume of the at least one fluid chamber may vary in response to a mechanical input. For example, the at least one fluid chamber volume may vary in response to a rotation of the cam follower relative to the cam track.

The device may comprise a motor. A volume of the at least one fluid chamber may vary in response to a fluid pressure. For example, the at least one fluid chamber volume may vary in response to a fluid pressure differential, such as differential fluid pressure across the inlet and/or the outlet.

The device may comprise an engine. For example, at least a portion of the at least one fluid chamber may comprise a combustion chamber. The at least one fluid chamber volume may vary in response to a change in internal at least one fluid chamber pressure, such as caused by a combustion therein.

The device may be configured to transfer a bore fluid. . The device may be configured to transfer a bore fluid within a bore of the device, such as axially transfer an internal bore fluid and/or axially transfer an external bore fluid. The device may be configured to transfer a bore fluid between an internal device bore and an external device bore. The device may be configured to transfer a bore fluid substantially radially.

The device may comprise a downhole device. The bore fluid may comprise a drilling fluid. The bore fluid may comprise a formation fluid. The bore fluid may comprise an injection fluid. The device may comprise a downhole pump. The device may comprise a downhole motor.

In use, the first cam track wall means and first cam follower wall means may selectively abut, strike, ride over or upon, slide relative to, and/or contact one another. In use, the first cam track wall means and the first cam follower wall means may contact one another such as to form a seal therebetween. The seal may be a continuous seal. The seal may be a dynamic seal.

In this way the first cam track wall means and first cam follower wall means may interact with, co-act or ride upon one another such that at least part of a motion of the cam track defines or determines at least part of a motion of the cam follower or vice versa. The wave may comprise a flattened or neutral portion of the waveform. The may comprise a portion configured to maintain a relative axial position of the cam track and cam follower during relative rotation therebetween. For example, the waveform may comprise a flattened or substantially circumferential portion. The flattened or substantially circumferential portion may correspond to a closed and/or open period/s of the inlet/s and/or the outlet/s. The period/s may provide for a transition between opening and/or closing the inlet/s and/or the outlet/s. For example, the period/s may provide for a transition/s between opening the inlet and closing the outlet.

At least part of the cam track may be in the form of a wave having an amplitude and a wavelength, the wave having a forward throw section and a rearward throw section, at least one of the forward throw section or rearward throw section being of a steeper gradient than the forward throw section or rearward throw section respectively of a sinusoidal cam track of equivalent amplitude and wavelength. The forward throw section may be of a steeper gradient than the forward throw section of a sinusoidal cam track. Alternatively or in addition the rearward throw section may be of a steeper gradient.

The cam track may incorporate a substantially straight section. This may conveniently form part of the forward throw section. Alternatively, or in addition, the cam track may incorporate a straight section in the rearward throw section, and/or in the peak or trough sections. The cam track may be of a truncated zig-zaggy form; that is, substantially straight throw sections with substantially flat peaks and troughs. Alternatively, only the forward throw sections may be substantially straight, with the rearward throw section being curved. The rearward throw section may be either steeper or less steep than that of an equivalent sinusoidal cam track. The cam track wall means may be rotationally or circumferential ly continuous.

The wave/s or waveform/s may comprise one or more of: a periodic wave; a sinusoidal waveform; an angular waveform; a slope or wedge; an undulating waveform; a step waveform; a block waveform; a castellated waveform; and/or a flattened or neutral portion of the waveform. The wave/s or waveform/s may be defined by an inclined plane; such as a plane inclined at an angle to a cross-section of the device perpendicular to the central axis. The angle of inclination may be one or more of: about 2 to 5 degrees; about 5 to 10 degrees; about 15 to 20 degrees; about 25 to 30 degrees; about 35 to 40 degrees; about 45 to 50 degrees; relative to the cross- sectional plane or relative to the central axis. The inlet/s and/or outlet/s may be bidirectional. The inlet/s and/or outlet/s may comprise an aperture, a port or an opening.

The inlet/s and/or outlet/s may be valve-free.

The inlet/s and/or outlet/s may be unidirectional. For example, the inlet/s and/or outlet/s may comprise valve/s, such as a one way valve/s.

The device may be configured to provide a discontinuous contact or engagement between the cam follower and the cam track. The device may be configured to provide an axial displacement of the cam follower relative to the cam track. The axial displacement may comprise a ricochet, flapping, stroking, overshot or the like. The device may be configured to provide a clearance between the first cam track and cam follower for at least a portion of the rotation and/or axial movement.

The device may be configured to permit a flow of particles or solids through the inlet/s and/or outlet/s and/or the fluid chamber/s and/or the throughbore/s and/or the annulus/i. The device may be configured to flow particles or solids through the inlet/s and/or outlet/s and/or the fluid chamber/s and/or the throughbore/s and/or the annulus/i. The device may be configured to flush particles or solids through the inlet/s and/or outlet/s and/or the fluid chamber/s and/or the throughbore/s and/or the annulus/i.

The device may be configured to filter particles or solids to prevent their passage through the inlet/s and/or outlet/s and/or the fluid chamber/s and/or the throughbore/s and/or the annulus/i.

The particles or solids may comprise particulates and/or precipitate/s and/or sand and/or debris, such as from downhole equipment, formations, workovers, reservoirs or the like,

The inlet/s and/or outlet/s may be configured to accommodate the particles or solids.

The first and/or second axial member/s may be configured to accommodate the particles or solids. The device may be configured to provide a clearance between the first and second axial members, such as a clearance between the first and second axial members throughout an entire cycle of relative movement between the first and second axial members. The device may be configured to prevent particles or solids being trapped or compressed between the first and second axial members. The device may comprise a particle recess, cavity or sump for receiving particles, such as when the chamber is in a minimum volume state or substantially closed. The device may be configured to permit a rapid opening and/or closing of the inlet/s and/or outlet/s. The device may be configured to selectively open and/or close the inlet/s and/or outlet/s. The cam follower and/or cam track may be configured to selectively open and/or close the inlet/s and/or outlet/s. The cam follower and/or cam track may be configured to selectively open and/or close the inlet/s and/or outlet/s according to a relative rotational position. A first rotational position of the cam follower relative to the cam track may correspond to an open and/or closed position/s of the inlet/s and/or outlet/s. For example, the first rotational position of the cam follower relative to the cam track may correspond to an open position of the inlet and a closed position of the outlet (or vice versa). A second rotational position of the cam follower relative to the cam track may correspond to an open and/or closed position/s of the inlet/s and/or outlet/s. For example, the second rotational position of the cam follower relative to the cam track may correspond to a closed position of the inlet and an open position of the outlet (or vice versa).

A rotational position of the cam follower relative to the cam track may correspond to a specific volume of the at least one fluid chamber. A rotational position of the cam follower relative to the cam track may correspond to an increasing or a constant or a decreasing volume of the at least one fluid chamber. A rotational position of the cam follower relative to the cam track may correspond to an axial position of the cam follower relative to the cam track.

The device may be configured to selectively open the inlet according to a rotational position of the cam follower relative to the cam track. The device may be configured to selectively maintain the inlet open according to a rotational position of the cam follower relative to the cam track. The device may be configured to selectively close the inlet according to a rotational position of the cam follower relative to the cam track. The device may be configured to selectively maintain the inlet closed according to a rotational position of the cam follower relative to the cam track.

The cam follower may be configured to open the inlet when the cam follower rotates to a position corresponding to a minimum at least one fluid chamber volume. The cam follower may be configured to maintain the inlet open when the cam follower is rotating relative to the cam track such that the at least one fluid chamber volume is increasing. Accordingly, the cam follower may maintain the inlet open when underpressure in the at least one fluid chamber is created or present. Accordingly, fluid may be drawn into the at least one fluid chamber through the inlet (for example, when functioning as a pump and/or as an engine). The cam follower may be configured to close the inlet when the cam follower rotates to a position corresponding to a maximum at least one fluid chamber volume. The cam follower may be configured to maintain the inlet closed when the cam follower is rotating relative to the cam track such that the at least one fluid chamber volume is decreasing. Accordingly, the cam follower may maintain the inlet closed when overpressure in the at least one fluid chamber is created or present. The cam follower may be configured to close the outlet when the cam follower rotates to a position corresponding to a minimum at least one fluid chamber volume. The cam follower may be configured to maintain the outlet closed when the cam follower is rotating relative to the cam track such that the at least one fluid chamber volume is increasing. Accordingly, the cam follower may maintain the outlet closed when underpressure in the at least one fluid chamber is created or present. The cam follower may be configured to open the outlet when the cam follower rotates to a position corresponding to a maximum at least one fluid chamber volume. The cam follower may be configured to maintain the outlet open when the cam follower is rotating relative to the cam track such that the at least one fluid chamber volume is decreasing. Accordingly, the cam follower may maintain the outlet open when overpressure in the at least one fluid chamber is created or present. Accordingly, fluid may be expelled through the outlet.

The cam follower may be configured to open the inlet when the cam follower is rotated to a position corresponding to a minimum at least one fluid chamber volume (e.g. when functioning as a motor). The cam follower may be configured to maintain the inlet open when the at least one fluid chamber volume is increasing under fluid pressure such that the cam follower is rotating relative to the cam track. Accordingly, the cam follower may maintain the inlet open when overpressure in the at least one fluid chamber is created or present. Accordingly, fluid may be pumped into the at least one fluid chamber through the inlet (for example, when functioning as a motor or engine). Accordingly a relative movement of the cam follower relative to the cam track may be driven by a pumped fluid. The relative movement may be axial and/or rotational. The cam follower may be configured to close the inlet when the cam follower is rotated to a position corresponding to a maximum at least one fluid chamber volume. The cam follower may be configured to maintain the inlet closed when the at least one fluid chamber volume is decreasing such that the fluid is expelled. Accordingly, the cam follower may maintain the inlet closed when overpressure in the at least one fluid chamber is present. The cam follower may be configured to close the outlet when the cam follower rotates to a position corresponding to a minimum at least one fluid chamber volume. The cam follower may be configured to maintain the outlet closed when the at least one fluid chamber volume is increasing such that the cam follower is rotating relative to the cam track. Accordingly, the cam follower may maintain the outlet closed when overpressure in the at least one fluid chamber is created or present. The cam follower may be configured to open the outlet when the cam follower rotates to a position corresponding to a maximum at least one fluid chamber volume. The cam follower may be configured to maintain the outlet open when the at least one fluid chamber volume is decreasing such that the cam follower is rotating relative to the cam track. Accordingly, the cam follower may maintain the outlet open to vent the chamber to create an underpressure to decrease the volume of the chamber.

The device may comprise an outer member. The outer member may be longitudinal. The outer member may form a housing for the cam track and/or the cam follower. An inner wall of the outer member may define an outer wall of the at least one fluid chamber. The outer member may comprise a sleeve. The outer member may comprise a mandrel. The outer member may be configured to connect to an external apparatus, such as a casing, liner, coiled tubing, tubular, drillstring or the like.

The device may comprise a hollow center. The hollow center may provide or define an axial fluid passage. The axial fluid passage may be closed or closable at at least one axial end. For example, the axial fluid passage may be selectively closable and/or openable, such as by a plug, a valve, an obstruction (e.g. a drop-ball) or the like.

The device may comprise an inner member. The inner member may be longitudinal. An outer wall of the inner member may define an inner wall of the at least one fluid chamber. The inner member may comprise a shaft. The device may comprise a throughbore. The device may comprise an axial throughbore. The inner member may comprise a throughbore. The inner member may comprise a blind throughbore. The inner member may comprise one or more lumen/s. The inner member may comprise one or more fluid conduit/s. The inner member may comprise a substantially hollow shaft. The inner member may comprise a mandrel. The inner member may be configured to connect to an external apparatus, such as a toolstring, coiled tubing, tubular, slickline, wireline, motor or the like.

The inner and outer members may be coaxially arranged. The inner and outer members may be concentrically arranged. The inner and outer members may be coaxially arranged with the central axis. The inner and outer members may be relatively rotatable about the central axis. The inner and outer members may be relatively axially movable. Alternatively, the inner and outer members may be relatively axially fixed. The at least one fluid chamber may comprise an annular fluid chamber. The at least one fluid chamber may comprise a portion of an annulus between the inner and outer members.

The at least one fluid chamber may comprise an axial fluid chamber. The at least one fluid chamber may comprise an axial fluid chamber adjacent or axially displaced from the cam follower and/or the cam track.

The inlet/s and/or outlet/s may be substantially radially arranged.

The device may be configured to transfer fluid substantially radially. For example, the device may be configured to transfer fluid from between an inner member fluid conduit and an annulus or other fluid conduit outside the outer body. The throughbore may comprise the inner member fluid conduit.

The inlet/s and/or outlet/s may be substantially axially arranged.

The device may be configured to transfer fluid substantially axially. For example, the device may be configured to transfer fluid from a first fluid conduit at a first end of the inner member to a second fluid conduit at a second end of the inner member.

The inner member may comprise the inlet and/or the outlet. The outer member may comprise the inlet and/or the outlet.

The cam follower may comprise the inlet and/or the outlet. The cam track may comprise the inlet and/or the outlet.

The cam follower may be rotationally fixed relative to the inner member. The cam follower may be rotatable with the inner member. The cam track may be rotationally fixed relative to the outer member. The cam track may be rotatable with the outer member.

Alternatively, the cam track may be rotationally fixed relative to the inner member. The cam track may be rotatable with the inner member. The cam follower may be rotationally fixed relative to the outer member. The cam follower may be rotatable with the outer member.

The cam follower may be axially fixed to the inner member. The cam follower may be axially moveable with the inner member. The cam track may be axially movable relative to the outer member. The cam track may be axially movable relative to the inner member. The cam track may be relatively axially movable so as to ensure axial contact between the first cam track wall means and the first cam follower wall means. The cam track may be relatively axially urged. For example, the cam track may be axially urged by a fluid pressure (e.g. acting as a piston). The cam track may be spring-mounted. For example the device may comprise a resilient or spring member. The cam track may be relatively axially driven. For example, the cam track may be axially driven by an adjacent second device. The cam track may be keyed to the outer member.

The cam follower may be axially moveable relative to the inner member. The cam track may be axially fixed to the outer member. The cam follower may be axially movable relative to the outer member. The cam follower may be relatively axially movable so as to ensure axial contact between the first cam track wall means and the first cam follower wall means. The cam follower may be relatively axially urged. For example, the cam follower may be axially urged by a fluid pressure (e.g. acting as a piston). The cam follower may be spring-mounted. For example the device may comprise a resilient or spring member. The cam follower may be relatively axially driven. For example, the cam follower may be axially driven by an adjacent second device. The cam follower may be keyed to the inner member.

The device may comprise a plurality of fluid chambers. The device may comprise a plurality of chambers substantially circumferentially arranged. The device may comprise a plurality of chambers substantially axially arranged. The plurality of fluid chambers may be separated by a portion/s of the cam follower. The device may comprise one or more pair/s of fluid chambers. The pair/s of fluid chambers may be symmetrically arranged. The pair/s of fluid chambers may be opposed. The pair of fluid chambers may be axially opposed. The pair of fluid chambers may be radially opposed. The pair of fluid chambers may be axially separated by the cam follower. The pair of chambers may be circumferentially separated by the cam follower. The pair/s of fluid chambers may be arranged to provide a balanced relative movement between the cam follower and the cam track. The chambers may comprise a common inlet and/or outlet. For example, an inlet or outlet may rotate relative to the chambers such that the inlet and/or outlet is in sequential fluid communication with the respective chambers. Each chamber may comprise an inlet and an outlet. The inlet/s and outlet/s of each chamber may be configured to be in selective fluid communication with the respective fluid chamber. The device may be configured such that the inlet of a first fluid chamber of a pair is open whilst the inlet of a second fluid chamber of the pair is closed (and vice versa). The device may be configured such that the outlet of a first fluid chamber of a pair is closed whilst the outlet of a second fluid chamber of the pair is open (and vice versa). The device may be configured such that the inlet of a first fluid chamber of a pair is opened whilst the inlet of a second fluid chamber of the pair is closed (and vice versa). The device may be configured such that the outlet of a first fluid chamber of a pair is closed whilst the outlet of a second fluid chamber of the pair is opened (and vice versa). The device may be configured such that the first chamber of the pair urges the cam follower in a first axial direction corresponding to a first rotational position and the second chamber of the pair urges the cam follower in a second axial direction corresponding to a second rotational position. The first and second axial directions may be substantially opposite. The first and second rotational positions may be substantially out of phase.

The cam follower may drive the inner member (e.g. when functioning as a motor or an engine). The cam follower may drive the outer member.

The cam follower may be driven by the inner member (e.g. when functioning as a pump). The cam follower may be driven by the outer member.

The cam track may drive the inner member (e.g. when functioning as a motor or an engine). The cam track may drive the outer member.

The cam track may be driven by the inner member (e.g. when functioning as a pump). The cam track may be driven by the outer member.

The device may comprise a seal. For example, the device may comprise a selective seal/s between the cam follower and the inlet/s and/or the outlet/s. The seal may be annular. The seal may be axial.

The cam follower may comprise a disk. The cam follower may be substantially annular. The cam follower may comprise a ring. The cam follower may comprise a torus. The cam follower may comprise a substantially uniform outer diameter. A substantially uniform outer diameter may allow for an annular seal, such as a circumferential seal (e.g. an O-ring or the like). The cam follower may comprise a substantially uniform inner diameter. A substantially uniform inner diameter may allow for an annular seal, such as a circumferential seal (e.g. an O-ring or the like).

The inlet/s and/or outlet/s may comprise a direction-dependent form. For example, the inlet/s and/or outlet/s may comprise a non-uniform axial alignment. The inlet/s and/or outlet/s may comprise a slot form. The inlet/s and or outlet/s may comprise a variable cross-section. The inlet/s and or outlet/s may comprise a variable cross-sectional area. For example, the inlet/s may comprise a smaller cross-sectional area corresponding to an initial stage of opening, relative to a later stage of opening (and/or vice versa).

The inlet/s and/or the outlet/s may comprise a substantially homogenous form. The device may further comprise a second cam track wall means and the cam follower may comprise a second cam follower wall means, and the second cam track wall means and second cam follower wall means may face one another.

The first and second cam track wall means may be disposed so as to face one another.

The first and second cam follower wall means may be disposed so as to oppose one another, e.g. back to back.

In such disposition the cam follower means may be provided within the cam track, e.g. between the first and second cam track walls. The cam follower may be of a substantially homogenous thickness around a circumference and/or across a diameter of the cam follower. The cam follower may comprise a rotor axially sandwiched between two stators.

The second cam track wall means may comprise or provide a second cam track wave or waveform.

The second cam follower wall means may comprise or provide a second cam follower wave or waveform.

In use, the second cam track wall means and second cam follower wall means may selectively abut, strike, ride over or upon slide relative to and/or contact one another.

In this way the second cam track wall means and second cam follower wall means may interact with, co-act or ride upon one another such that at least a further part of a motion of the cam track defines at least a further part of a motion of the cam follower or vice versa.

The first cam track wall means may be rotationally or circumferentially continuous.

The first cam track wave may comprise a periodic waveform.

The first cam track wave may comprise a sinusoidal waveform.

The first cam track wave may comprise an angular waveform. For example, the first cam track wave may comprise a slope or wedge.

The first cam track wave may comprise an undulating waveform.

The first cam track may comprise a step waveform.

The first cam track wave may comprise a block waveform.

The first cam track wave may comprise a castellated waveform.

The first cam track wave may comprise a flattened or neutral portion of the waveform. The first cam track may comprise a portion configured to maintain a relative axial position of the cam track and cam follower during relative rotation therebetween. For example, the waveform may comprise a flattened or substantially circumferential portion. The flattened or substantially circumferential portion may correspond to a closed and/or open period/s of the inlet/s and/or the outlet/s. The period/s may provide for a transition between opening and/or closing the inlet/s and/or the outlet/s. For example, the period/s may provide for a transition/s between opening the inlet and closing the outlet.

The second cam track wall means may be rotationally or circumferentially continuous.

The second cam track wave may comprise a periodic waveform.

The second cam track wave may comprise a sinusoidal waveform.

The second cam track wave may comprise an angular waveform. For example, the second cam track wave may comprise a slope or wedge.

The second cam track wave may comprise an undulating waveform.

The second cam track may comprise a step waveform.

The second cam track wave may comprise a block waveform.

The second cam track wave may comprise a castellated waveform.

The second cam track wave may comprise a flattened or neutral portion of the waveform. The second cam track may comprise a portion configured to maintain a relative axial position of the cam track and cam follower during relative rotation therebetween. For example, the waveform may comprise a flattened or substantially circumferential portion. The flattened or substantially circumferential portion may correspond to a closed and/or open period/s of the inlet/s and/or the outlet/s. The period/s may provide for a transition between opening and/or closing the inlet/s and/or the outlet/s. For example, the period/s may provide for a transition/s between opening the inlet and closing the outlet.

The first cam follower wall means may be rotationally or circumferentially continuous.

Alternatively, the first cam follower wall means may be provided on a plurality of spaced cam follower members. In such case each cam follower member may define at least part of the first and/or second cam follower walls and/or waves.

The first cam follower wall means may comprise or define a periodic waveform.

The first cam follower wall means may comprise or define a sinusoidal waveform. The second cam follower wall means may be rotationally or circumferentially continuous.

Alternatively or additionally, the second cam follower wall means may be provided on the or a further plurality of spaced cam follower members.

The second cam follower wall means may comprise or define a periodic waveform.

The second cam follower wall means may comprise or define a sinusoidal waveform.

The cam follower may comprise at least first and second parts assembled to provide a rotationally or circumferentially continuous cam follower.

A distance between a peak of the first cam track wave and a peak of the second cam track wave may be the same as a distance between a peak of the first cam follower wave and a peak of the second cam follower wave.

A distance between a peak of the first cam track wave and a peak of the second cam track wave may be less than a distance between a peak of the first cam follower wave and a peak of the second cam follower wave.

In a preferred implementation a period or frequency of the first and second cam track waveforms and first and second cam follower waveforms are substantially the same.

The amplitude of the first cam track waveform and first cam follower waveform may be substantially the same.

The amplitude of the second cam track waveform and second cam follower waveform may be substantially the same.

In a preferred embodiment all of the waveforms may have the same frequency and amplitude.

Advantageously peaks of the first and second cam track waveforms are circumferentially or radially coincident or longitudinally face one another.

Advantageously troughs of the first and second cam track waveforms are circumferentially radially coincident or longitudinally face one another.

Advantageously peaks of the first and second cam follower waveforms are circumferentially or radially coincident or longitudinally oppose one another.

Advantageously troughs of the first and second cam follower waveforms are circumferentially or radially coincident or longitudinally oppose one another.

Advantageously a distance between peaks of the first and second cam track walls is less than a distance between peaks of the first and second cam follower walls. Preferably the cam track is provided circumferentially on a cam cylinder.

The cam follower may comprise a piston head. The cam track may comprise a cylinder.

There may be provided rotary drive means for rotarily driving the cam track. In such instance the rotary motion of the cam track may be converted into reciprocal (longitudinal) motion of the cam follower means.

There may be provided rotary drive means for rotarily driving the cam follower means. In such instance the rotary motion of the cam follower means may be converted into reciprocal (longitudinal) motion of the cam track.

There may be provided reciprocal (longitudinal) drive means for reciprocally driving the cam track. In such instance the reciprocal motion of the cam track may be converted into rotary motion of the cam follower means.

There may be provided reciprocal (longitudinal) drive means for reciprocally driving the cam follower means. In such instance the motion of the cam follower means may be converted into rotary motion of the cam track.

The device may comprise an ignition means. For example, the combustion portion of the at least one fluid chamber may comprise a spark plug. The at least one fluid chamber may comprise a plurality of inlets and/or outlets. For example, the at least one fluid chamber may comprise a first inlet for a first fluid and a second inlet for a second fluid. The first and second fluids may generate a combustion. The combustion may cause an expansion of the at least one fluid chamber resulting in a mechanical output of a rotational and/or an axial movement of the cam follower relative to the cam track (or vice versa).

The cam follower may be configured to move relative to the cam track in a single direction (e.g. clockwise or counter-clockwise). The cam follower may comprise an asymmetrical rotational profile.

The device may be configured to operate in reverse. For example, the device may be configured to operate as a pump in a first mode of operation and to operate as a motor in a second mode of operation. The modes of operation may be dependent on external factors. For example, the modes of operation may be dependent on external fluid pressure/s.

According to an aspect of the invention there is provided a method of transferring a fluid comprising:

providing a device comprising a cam track and a cam follower, wherein the cam track comprises a first cam track wall means, the cam follower comprises a first cam follower wall means, and the first cam track wall means and first cam follower wall means face one another, and wherein at least one of the first cam track wall means and/or the first cam follower wall means comprises or provides a wave or waveform; disposing at least one fluid chamber between the cam track and the cam follower;

flowing a fluid into the at least one fluid chamber via a fluid inlet;

moving the cam follower relative to the cam track; and

flowing a fluid out of the at least one fluid chamber via a fluid outlet.

The method may comprise varying the volume of the at least one fluid chamber according to a rotational position of the cam follower relative to the cam track. The method may comprise varying the at least one fluid chamber volume according to an axial position of the cam follower relative to the cam track.

The method may comprise varying a rotational position of the cam follower relative to the cam track according to the volume of the at least one fluid chamber. The method may comprise varying an axial position of the cam follower relative to the cam track according to the volume of the at least one fluid chamber.

The method may comprise pumping a fluid. The method may comprise providing a mechanical input. The method may comprise varying a volume of the at least one fluid chamber in response to a mechanical input. For example, method may comprise varying a volume of the at least one fluid chamber in response to a rotation of the cam follower relative to the cam track.

The method may comprise providing a fluid pressure input. The method may comprise providing a mechanical output. The method may comprise varying a volume of the at least one fluid chamber in response to a fluid pressure. For example, the method may comprise varying a volume of the at least one fluid chamber in response to a fluid pressure differential, such as differential fluid pressure across the inlet and/or the outlet.

The method may comprise combusting a fluid in the chamber. The method may comprise varying a volume of the at least one fluid chamber in response to a change in internal fluid chamber pressure, such as caused by a combustion therein.

According to an aspect of the invention there is provided an apparatus comprising one or more devices according to any other aspect.

The apparatus may comprise a plurality of devices.

The plurality of devices may comprise a plurality of similar devices. For example, the apparatus may comprise a plurality of pump devices. The plurality of devices may comprise a plurality of dissimilar devices. For example, the apparatus may comprise at least one motor and at least one pump. The motor may drive the pump. The plurality of devices may comprise a combination of dissimilar devices and/or similar device/s.

The plurality of devices may be arranged in parallel. The plurality of devices may be coaxially arranged. The plurality of devices may be axially arranged.

The plurality of devices may be arranged in series. The plurality of devices may be radially arranged.

The apparatus may comprise a symmetrical arrangement of devices. The symmetrical arrangement may be rotationally symmetrical. The symmetrical arrangement may be an inversion (e.g. a second device may mirror a first device).

The plurality of devices may be arranged to provide a smooth output. The smooth output may be a mechanical output. The smooth output may be a fluid output.

The apparatus may be configured to synchronise the opening and/or closing of the inlet/s and/or outlet/s of the respective devices. For example, the plurality of devices may be connected such that all outlets are simultaneously opened and closed. Accordingly, it may be assured that fluid does not flow from a chamber of a first device into a chamber of a second device.

Alternatively, the plurality of devices may be connected such that the inlets and outlets of respective devices are sequentially opened and closed. Accordingly, an output of the apparatus may be smoothed across a complete cycle (such as a full rotation of an inner or outer member).

The plurality of devices may be mounted to a common member/s. For example, the plurality of devices may comprise a single common outer member. The plurality of devices may comprise a single common inner member.

The plurality of devices may be axially balanced. The plurality of devices may be rotationally balanced.

The plurality of devices may be configured to be in phase.

The plurality of devices may be configured to be out of phase. The plurality of devices may be configured to be in antiphase.

The plurality of devices may be connected. For example, the plurality of devices may be connected such that a single input (e.g. a rotation of an inner member or an external fluid pressure) drives the plurality of devices. The plurality of devices may be connected such that the devices drive a single output (e.g. a rotation of an inner member or a generation of a fluid pressure). The apparatus may be configured to use an output of a first device as an input to a second device. A first device may be configured to provide an input to a second device. For example a motor may be configured to provide a mechanical input to a pump.

The apparatus may comprise a downhole tool.

The apparatus may comprise a drive for a downhole drilling tool.

The apparatus may comprise a downhole drilling tool.

The apparatus may comprise a mud pump.

The apparatus may comprise a mud motor.

The apparatus may comprise a downhole motor.

The apparatus may comprise a downhole pump.

The apparatus may comprise a downhole pump configured to pump fluid to surface form a reservoir with insufficient hydrostatic pressure.

The apparatus may comprise a downhole injection pump.

The fluid may comprise water. The device may comprise a dewatering device.

The device may be configured to transport light or non-viscous fluids.

The inner and/or outer and/or first and/or second axial member/s may comprise materials suitable for use downhole, such as to withstand a high pressure high temperature condition. The inner and/or outer and/or first and/or second axial member/s may comprise a metal, such as steel, titanium, alloys or the like and/or a plastic, such as PEEK, and/or a ceramic.

The device may comprise a medical device. The device may comprise an implantable device. The device may comprise a prosthesis. The device may comprise an endoprosthesis. The fluid may comprise a bodily fluid. The fluid may comprise blood. The inner and/or outer and/or first and/or second axial member/s may comprise materials suitable for implantation, such as to be accepted and/or to inghibit and/or discourage integration into an implantation site. The inner and/or outer and/or first and/or second axial member/s may comprise a metal, such as steel, titanium, alloys, nitinol, or the like and/or a plastic, such as PTFE or PE or PP, and/or a ceramic.

The fluid may comprise a liquid and/or a gas. The fluid may comprise a plurality of fluids, such as a mixture of fluids.

A first device operating as a motor may be driven by a fluid supplied via the throughbore and/or external to the device (e.g. an external annulus) and/or by a fluid supplied in an additional fluid conduit, such as a hydraulic fluid supply line. An exhaust fluid from the first device/motor may be transported with an input or an output of a second device/pump. The exhaust fluid of the motor may be transported via the throughbore and/or an external annulus. The exhaust fluid may be transported in additional fluid conduit, such as a hydraulic fluid exhaust line.

The plurality of devices may be configured to transport a similar fluid. The motor may be driven by a similar fluid to that output from a pump. The motor may be configured to be driven by a fluid transported by the pump, such as transported to another location (e.g. a surface or wellhead location of a downhole pump) and returned to the motor (e.g. after filtering or de-watering).

The wave form may at least partially define the relative axial displacement according to the relative rotational position.

The invention includes one or more corresponding aspects, embodiments or features in isolation or in various combinations whether or not specifically stated (including claimed) in that combination or in isolation. For example, it will readily be appreciated that features recited as optional with respect to the first aspect may be additionally applicable with respect to the other aspects without the need to explicitly and unnecessarily list those various combinations and permutations here. Features recited as optional with respect to a cam track and/or cam follower may be applicable to a first and/or second axial member/s, and vice versa.

In addition, corresponding means for performing one or more of the discussed functions are also within the present disclosure.

It will be appreciated that one or more embodiments/aspects may be useful in transferring a fluid.

The above summary is intended to be merely exemplary and non-limiting.

As used herein, the term "comprise" is intended to include at least: "consist of";

"consist essentially of"; "include"; and "be". For example, it will be appreciated that where the device may "comprise a pump", the device may "include a pump" (and optionally other element/s); the device "may be a pump"; or the device may "consist of a pump"; etc. For brevity and clarity not all of the permutations of each recitation of "comprise" have been specifically stated.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows a perspective view of a portion of a fluid transfer device in accordance with a first embodiment of the invention;

Figure 2 shows a plan view of the fluid transfer device of Figure 1 ;

Figure 3 shows the fluid transfer device of Figure 1 in a first rotational position; Figure 4 shows the fluid transfer device of Figure 1 in a second rotational position;

Figure 5 shows the fluid transfer device of Figure 1 in a third rotational position; Figure 6 shows the fluid transfer device of Figure 1 in a fourth rotational position;

Figure 7 shows a perspective view of a portion of a fluid transfer device in accordance with a second embodiment of the invention;

Figure 8 shows a plan view of the fluid transfer device of Figure 7;

Figure 9 shows the fluid transfer device of Figure 7 in a first rotational position;

Figure 10 shows the fluid transfer device of Figure 7 in a second rotational position;

Figure 11 shows the fluid transfer device of Figure 7 in a third rotational position;

Figure 12 shows the fluid transfer device of Figure 7 in a fourth rotational position;

Figure 13 shows a plan view of a fluid transfer device in accordance with a third embodiment of the invention;

Figure 14 shows a partial view of the fluid transfer device of Figure 13 in a first rotational position;

Figure 15 shows a partial view of the fluid transfer device of Figure 13 in a second rotational position;

Figure 16 shows a partial view of the fluid transfer device of Figure 13 in a third rotational position;

Figure 17 shows a partial view of the fluid transfer device of Figure 13 in a fourth rotational position;

Figure 18 shows a partial view of the fluid transfer device of Figure 13 in a fifth rotational position;

Figure 19 shows a partial view of the fluid transfer device of Figure 13 showing external porting in the first rotational position of Figure 14;

Figure 20 shows a partial view of the fluid transfer device of Figure 13 showing external porting in a first intermediate rotational position; Figure 21 shows a partial view of the fluid transfer device of Figure 13 showing external porting in a second intermediate rotational position;

Figure 22 shows a partial view of the fluid transfer device of Figure 13 showing external porting in a third intermediate rotational position;

Figure 23 shows a partial view of the fluid transfer device of Figure 13 showing external porting in the third rotational position of Figure 16;

Figure 24 shows a partial view of the fluid transfer device of Figure 13 showing external porting in a fourth intermediate rotational position;

Figure 25 shows a partial view of the fluid transfer device of Figure 13 showing external porting in the fifth rotational position of Figure 18;

Figure 26 shows a partial view of the fluid transfer device of Figure 13 showing internal porting in the third rotational position of Figures 16 and 23;

Figure 27 shows a plan view of the fluid transfer device of Figure 13 corresponding to the rotational position of Figure 26 and indicating the direction of view shown in Figure 26;

Figure 28 shows a partial view of the fluid transfer device of Figure 13 showing internal porting in the second rotational position of Figures 16, 23, 26 and 27, viewed from a direction at 90° from Figure 26;

Figure 29 shows a plan view of the fluid transfer device of Figure 13 corresponding to the rotational position of Figure 28 and indicating the direction of view shown in Figure 28;

Figure 30 shows a partial view of the fluid transfer device of Figure 13 showing internal porting in a fifth intermediate position viewed from a similar direction to Figure 28;

Figure 31 shows a plan view of the fluid transfer device of Figure 13 corresponding to the rotational position of Figure 30 and indicating the direction of view shown in Figure 30;

Figure 47 shows a view of a fluid transfer device in accordance with a fourth embodiment of the invention in a first rotational position;

Figure 48 shows a partial view of the fluid transfer device of Figure 47 in a second rotational position;

Figure 49 shows a partial view of the fluid transfer device of Figure 47 in a third rotational position;

Figure 50 shows a partial view of the fluid transfer device of Figure 47 in a fourth rotational position; Figure 51 shows a partial view of the fluid transfer device of Figure 47 in a fifth rotational position;

Figure 52 shows a partial view of the fluid transfer device of Figure 47 in a sixth rotational position; and

Figure 53 shows a partial view of the fluid transfer device of Figure 47 in a seventh rotational position.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring initially to Figure 1 , there is shown a fluid transfer device, generally designated 10, in accordance with an embodiment of the present invention having a cam track 12 and cam follower 14 arrangement. The tool 10 comprises cam track 12 and cam follower 14 means adapted to run in the cam track, following a path. The first cam track wall means 16 provides a first cam track wave or waveform 30. The first cam follower wall means 18 provides a first cam follower wave or waveform 32. The cam track 12 comprises a first cam track wall means 16 and the cam follower 14 comprises a first cam follower means 18, and the first cam track wall means 16 and the first cam follower wall means 18 face one another. The device comprises a fluid chamber 20 disposed between the cam track 12 and the cam follower 14. The device 10 further comprises a fluid inlet 22 to the fluid chamber 20; and a fluid outlet 24 from the fluid chamber 20.

The cam track 12 and the cam follower 14 are coaxially arranged. In the embodiment shown, the cam follower 14 is configured to rotate about a central axis 28. The cam track 12 defines a rotational path about the central axis 28 for the cam follower 14.

A volume of the fluid chamber 20 corresponds to a rotational position of the cam follower 14 relative to the cam track 12. A volume of the fluid chamber 20 corresponds to an axial position of the cam follower 14 relative to the cam track 12. In the embodiment shown, the cam follower 14 comprises a rotor 17; and the cam track 12 comprises a stator 13.

In the embodiment shown, the device 10 is a pump. However, it will be readily appreciated, that in alternative embodiments, a motor of similar features may function in a substantially opposite mode of operation. A volume of the fluid chamber 20 varies in response to a mechanical input. The volume of the fluid chamber 20 varies in response to a rotation of the cam follower 14 relative to the cam track 12. The device 10 is a downhole device configured to transfer a bore fluid, which is a hydrocarbon from a reservoir (not shown). In use, the first cam track wall means 16 and first cam follower wall means 18 selectively abut, strike, ride over or upon, slide relative to, and/or contact one another. In this way the first cam track wall means 16 and first cam follower wall means 18 interact with or upon one another such that at least part of a motion (e.g. rotational motion) of the cam follower 14 defines at least part of a motion (e.g. longitudinal motion) of the cam track 12 or vice versa. In use, the first cam track wall means 16 and the first cam follower wall means 18 contact one another such as to form a continuous dynamic seal therebetween.

The inlet 22 and outlet 24 are bidirectional, in the form of ports. In alternative embodiments, the inlet/s and/or outlet/s may be unidirectional, such as one way valves.

The first cam track wall means 16 shown is rotationally or circumferentially continuous. The first cam track wave 30 comprises a periodic waveform. In Figure 1 , the first cam track wall means 16 comprises a sloped (wedge-shaped) form. The first cam track wave 30 comprises a substantially sinusoidal waveform with a rotational period of 1 (i.e. there is one complete wave around 360°).

In the embodiment shown, the first cam follower wave or waveform 32 is an inverted form of the first cam track wave or waveform 30. Accordingly, the first cam follower wall means 18 shown is rotationally or circumferentially continuous. The first cam follower wave 32 comprises a periodic waveform. In Figure 1 , the first cam follower wall means 18 comprises a sloped (wedge-shaped) form. The first cam follower wave 32 comprises a substantially sinusoidal waveform with a rotational period of 1 (i.e. there is one complete wave around 360°).

The device 10 comprises an outer (longitudinal) member 42. The outer member 42 forms a housing for the cam track 12 and the cam follower 14. An inner wall 44 of the outer member 42 defines an outer wall of the fluid chamber 20. The outer member 42 is configured to connect to an external apparatus, such as a casing, liner, coiled tubing, tubular, drillstring or the like (e.g. the outer member 42 comprises a box or screw connection, not shown).

The device 10 comprises an inner (longitudinal) member 46. An outer wall 48 of the inner member 46 defines an inner wall of the fluid chamber 20. The inner member 46 is a hollow shaft with a throughbore 50 in the embodiment shown. The inner member 46 is configured to connect to an external apparatus, such as a toolstring, coiled tubing, tubular, slickline, wireline, motor or the like (not shown).

The inner and outer members 42, 46 are coaxially and concentrically arranged about the central axis 28, as shown in Figure 2. The inner and outer members 42, 46 are relatively rotatable about the central axis 28. The inner and outer members 42, 46 are relatively axially movable.

The fluid chamber 20 comprises an annular fluid chamber, which is a portion of an annulus between the inner and outer members 42, 46.

The inlet 22 and outlet 24 are substantially radially arranged. The device 10 is configured to transfer fluid substantially radially. The inlet 22 is located in the outer member 42. The outlet 24 is located in the inner member 46. The device 10 is configured to transfer fluid between an annulus outside the outer body 42 and the throughbore 50.

The cam follower 14 is rotationally fixed relative to the inner member 46. The cam follower 14 is rotatable with the inner member 46. The cam track 12 is rotationally fixed relative to the outer member 42.

The cam follower 14 is axially moveable relative to the inner member 46. The cam track 12 is axially fixed to the outer member 42. The cam follower 14 is axially movable relative to the outer member 42. The cam follower 14 is relatively axially movable so as to ensure axial contact between the first cam track wall means 16 and the first cam follower wall means 18. The cam follower 14 is relatively axially urged. For example, the cam follower is axially urged by a fluid pressure (e.g. acting as a piston). For example, the cam follower 14 may be axially driven by an adjacent second device (not shown); such as with an opposing fluid chamber above the cam follower 14 (e.g. the cam follower 14 may comprise a cam follower for a mirrored second device, not shown). The cam follower 14 is fixed to the inner member 46.

The device 10 is configured to selectively open and close the inlet 22 and the outlet 24. The cam follower 14 is configured to selectively open and close the inlet 22 and the outlet 24 according to a relative rotational position. As shown in Figure 3, a first rotational position of the cam follower 14 relative to the cam track 12 corresponds to an closed position of the inlet 22 and an opening position of the outlet 24. A second rotational position of the cam follower 14 relative to the cam track 12 (Figure 4) corresponds to a closing position of the inlet 22 and a closed position of the outlet 24. A third rotational position of the cam follower 14 relative to the cam track 12 (Figure 5) corresponds to an open position of the inlet 22 and a closed position of the outlet 24. A fourth rotational position of the cam follower 14 relative to the cam track 12 (Figure 6) corresponds to a closed position of the inlet 22 and an open position of the outlet 24. The respective rotational positions shown in Figures 3 to 6 are separated by 90° rotations of the cam follower 14 with the inner member 46. Accordingly, it will be appreciated that fluid is pumped from the outlet 22 through the chamber 20 via the inlet 24 to the throughbore 50 by the sequential rotation between the respective rotational positions, as detailed below. It will also be appreciated that in alternative embodiments, or alternative modes of operation, a similar device may function as a pump for transferring fluid from the throughbore 50 through the chamber and out through the inlet 22 (i.e. the inlet 22 would function as an outlet and the outlet 24 would function as an inlet), such as by reversing the direction of relative rotation.

A rotational position of the cam follower 14 relative to the cam track 12 corresponds to a specific volume of the fluid chamber 20. A rotational position of the cam follower 14 relative to the cam track 12 corresponds to an increasing or a constant or a decreasing volume of the fluid chamber 20. A rotational position of the cam follower 14 relative to the cam track 12 corresponds to an axial position of the cam follower 14 relative to the cam track.

The device is configured to selectively open the inlet 22 according to a rotational position of the cam follower 14 relative to the cam track. The device is configured to selectively maintain the inlet 22 open according to a rotational position of the cam follower 14 relative to the cam track. The device is configured to selectively close the inlet 22 according to a rotational position of the cam follower 14 relative to the cam track. The device is configured to selectively maintain the inlet 22 closed according to a rotational position of the cam follower 14 relative to the cam track.

The cam follower 14 is configured to open the inlet 22 when the cam follower 14 is rotated to a position corresponding to a minimum fluid chamber 20 volume (Figure 3). The cam follower 14 is configured to maintain the inlet 22 open when the cam follower 14 is rotating relative to the cam track 12 such that the fluid chamber 20 volume is increasing (e.g. between Figures 3 and 5). Accordingly, the cam follower 14 maintains the inlet 22 open when underpressure in the fluid chamber 20 is created or present (Figures 4 and 5). Accordingly, fluid is drawn into the fluid chamber 20 through the inlet 22. The cam follower 14 is configured to close the inlet 22 when the cam follower 14 is rotated to a position corresponding to a maximum fluid chamber 20 volume (Figure 5). The cam follower 14 is configured to maintain the inlet 22 closed when the cam follower 14 is rotating relative to the cam track 12 such that the fluid chamber 20 volume is decreasing (between Figure 5 and Figure 6 and between Figure 6 and starting a new rotation at Figure 3). Accordingly, the cam follower 14 maintains the inlet 22 closed when overpressure in the fluid chamber 20 is created or present. The cam follower 14 is configured to close the outlet 24 when the cam follower 14 rotates to a position corresponding to a minimum fluid chamber 20 volume (Figure 3). The cam follower 14 is configured to maintain the outlet 24 closed when the cam follower 14 is rotating relative to the cam track 12 such that the fluid chamber 20 volume is increasing (e.g. between Figures 3 and 5). Accordingly, the cam follower 14 maintains the outlet 24 closed when underpressure in the fluid chamber 20 is created or present. The cam follower 14 is configured to open the outlet 24 when the cam follower 14 is rotated to a position corresponding to a maximum fluid chamber 20 volume (Figure 5). The cam follower 14 is configured to maintain the outlet 24 open when the cam follower 14 is rotating relative to the cam track 12 such that the fluid chamber 20 volume is decreasing (from Figure 5 to Figure 6 and from Figure 6 to a new rotation at Figure 3). Accordingly, the cam follower 14 maintains the outlet 24 open when overpressure in the fluid chamber 20 is created or present. Accordingly, fluid is expelled through the outlet 24.

Reference is now made to Figures 7 through 12, which show a fluid transfer device, generally designated 110, in accordance with a second embodiment of the present invention. The fluid transfer device 1 10 is generally similar to that shown in Figure 1 , with like features comprising like reference numerals, incremented by 100. Accordingly, the device 110 has a cam track 112 and cam follower 114 arrangement.

The first cam track wave 130 comprises a first neutral portion 134 of the waveform and a second neutral portion 136 of the waveform.

The first cam follower wave 132 comprises a first neutral portion 140 of the waveform and a second neutral portion 138 of the waveform.

The neutral portions 134, 136, 138, 140 are configured to maintain a relative axial position of the cam track 112 and cam follower 114 during relative rotation therebetween. Contact between the first neutral portions 134, 140 corresponds to a closing period of the inlet 122 (as shown in Figure 11). Contact between the first neutral portion 134 of the cam track 112 and the second neutral portion 138 of the cam follower 1 14; and between the second neutral portion 136 of the cam track 112 and the first neutral portion 140 of the cam follower 114 corresponds to a closing period of the outlet 124 (as shown in Figure 9). The periods provide for a transition between opening and closing the inlet 122 and the outlet 124; and for drawing fluid into and expelling fluid out of the chamber 120. Accordingly, no overlap in opening of the inlet 122 and the outlet 124 occurs (e.g. there is no simultaneous fluid communication with the chamber 120 via the inlet 122 and the outlet 124). Accordingly, any associated fluid pressure losses are reduced or eliminated. Reference is now made to Figures 13 through 31 , which show a fluid transfer device, generally designated 210, in accordance with a third embodiment of the present invention. The fluid transfer device 210 is generally similar to that shown in Figure 7, with like features comprising like reference numerals, incremented by 100. Accordingly, the device 210 has a cam track 212 and cam follower 214 arrangement. The device 210 further comprises a second cam track 251 with a second cam track wall means 252 and the cam follower 214 comprises a second cam follower wall means 254, and the second cam track wall means 252 and second cam follower wall means 254 face one another. The second cam track 251 is provided on a second stator 215.

The first and second cam track wall means 216, 252 are disposed so as to face one another.

The first and second cam follower wall means 218, 254 are disposed so as to oppose one another, e.g. back to back. In such disposition the cam follower 214 is disposed between the first and second cam track wall means 216, 252.

The second cam track wall means 252 comprises or provides a second cam track wave or waveform 256.

The second cam follower wall means 254 comprises or provides a second cam follower wave or waveform 258. The second cam follower wall means 254 is substantially in phase with the first cam follower wall means 218. Accordingly, the second cam follower waveform 258 is similar to the first cam follower waveform 238, separated by a thickness of the cam follower 214. In alternative embodiments, it will readily be appreciated that the second cam follower wall means may be out of phase with the first cam follower wall means (e.g. the second cam follower wall means and the second cam track wall means may be out of phase - for example, the second cam follower wall means may be an inversion of the first cam follower wall means)..

The device 210 comprises a plurality of fluid chambers 220, 260, 262, 264. The plurality of chambers 220, 260, 262, 264 comprises a first pair of radially opposed chambers 220, 260; and a second pair of radially opposed chambers 262, 264. The plurality of fluid chambers 220, 260, 262, 264 are separated by portions of the cam follower 214. The pairs of fluid chambers 220, 260, 262, 264 are symmetrically arranged. The first pair of fluid chambers 220, 260 is arranged to be axially opposed to the second pair of fluid chambers 262, 264. The pairs of fluid chambers 220, 260, 262, 264 are arranged to provide a balanced relative movement between the cam follower 214 and the cam tracks 212, 251. The first pair of chambers 220, 260 comprises a pair of common inlets 222, 266 and a pair of exclusive respective outlets 224, 268. The second pair of chambers 262, 264 comprises a pair of common second inlets 270, 272 and a pair of exclusive respective outlets 274, 276. The chambers 220, 260, 262, 264 rotate relative to the inlets 222, 266, 270, 272 such that the pairs of inlets 222, 266, 270, 272 are in sequential fluid communication with the respective pairs of chambers 220, 260, 262, 264. The outlets 224, 268, 274, 276 rotate with the respective chambers 220, 260, 262, 264. The device 210 is configured such that the inlets 222, 266, of the first pair of fluid chambers 220, 260 is open whilst the inlets 270, 272 of the second pair of fluid chambers 262, 264 are closed (and vice versa) as can be seen in Figures 19 to 25. The device 210 is configured such that the outlets 224, 268 of the first pair of fluid chambers 220, 260 are open whilst the outlets 274, 276 of the second pair of fluid chambers 262, 264 are closed (and vice versa) as can be seen in Figures 27 to 31.

The device 210 is configured such that rotation of the cam follower 14 with the inner member 246 urges the cam follower 214 in a first axial direction corresponding to a first rotational position (e.g. upwards between Figures 14, 15 and 16). Accordingly the first pair of fluid chambers 220, 260 are in expansion during rotation at the first rotational position; and the second pair of fluid chambers 262, 264 are in compression, balanced with the first pair of fluid chambers 220, 260. Further rotation of the cam follower 14 with the inner member 246 urges the cam follower 214 in a second axial direction corresponding to another rotational position (e.g. downwards between the third rotational position of Figures 16, to the rotational positions of Figures 17 and 18). Accordingly the first pair of fluid chambers 220, 260 are in compression during rotation at the further rotational position; and the second pair of fluid chambers 262, 264 are in expansion, balanced with the first pair of fluid chambers 220, 260.

The axially opposed first and second pairs of fluid chambers 220, 260, 262, 264 and the period of the waves (i.e. two complete waves per revolution) provides for a total of eight compressions and eight expansions per revolution (two for each of the four chambers 220, 260, 262, 264). Accordingly, the device 210 can provide for a smooth fluid transfer throughout a revolution. The inlets 222, 266, 270, 272 comprise a direction-dependent form, which is an offset slot form in the embodiment shown.

Reference is now made to Figures 32 to 46, which show a fluid transfer device 310, in accordance with a fourth embodiment of the present invention. The fluid transfer device 310 is generally similar to that shown in Figure 13, with like features comprising like reference numerals, incremented by 100. Accordingly, the device 310 has a cam track 312 and cam follower 314 arrangement. The device 310 has a cam track 312 in the form of a circumferential groove 378 in the cam follower 314; which receives corresponding pins or rollers 380 from the outer member 342. Accordingly, the axial movement of the cam follower 314 corresponding to rotational position is defined by the path of the cam track 312, as shown in Figure 34. Accordingly, the first and second stators 313, 315 are not required to bear all of the forces associated with the cam follower's 314 relative axial and rotational movement. In the embodiment shown, the device 310 comprises a pair of axially opposed fluid chambers 320, 362. The fluid chambers 320, 362 are singular annular chambers 320, 362. Accordingly no sealing contact is required between the walls of the rotor 315 and the stators 313, 315.

In alternative embodiments, it will be appreciated that a sealing member may be provided between the cam follower 314 and the first stator 313; and between the cam follower 314 and the second stator 315 (e.g. a resilient seal). Accordingly, a plurality (e.g. pair) of radially arranged or opposed chambers may be provided.

The cam follower 314 is keyed to the inner member 346, as shown in Figure 32, such that the cam follower 314 is axially movable relative to the inner member 246 (rather than only being axially movable with the inner member as in the second embodiment). Accordingly, the inner member 346 needs only to rotate; and no axial movement of the inner member 346 (or outer member 342) is required for operation of the device 310. The stators 313, 315 are fixed axially and rotationally to the outer member 342.

The device 310 functions similarly to that of Figures 13 to 31 , with fluid being sequentially drawn into the expanding fluid chambers 320, 362 through the respective fluid inlets; and expelled from the subsequently compressing chambers through the fluid outlets (not shown); as is shown sequentially in Figures 40 to 46 (similar to Figures 19 to 25). However, the wave form of the groove 378 has a greater amplitude relative to the opposing faces of the stators 313, 315 and the rotor 314. Accordingly, the rotor 314 has an increased axial movement compared to the device 210 of Figure 13. The increased axial movement allows the annular chambers 320, 362 to be sequentially axially opened and closed as shown in Figures 39 to 46.

Reference is now made to Figures 47 to 53, which show a fluid transfer device 410, in accordance with a fifth embodiment of the present invention. The fluid transfer device 410 is generally similar to that shown in Figure 32, with like features comprising like reference numerals, incremented by 100. Accordingly, the device 410 has a cam track 412 and cam follower 414 arrangement. The device 410 comprises a plurality of fluid chambers 420, 460, 462, 464. The plurality of chambers 420, 460, 462, 464 comprises a first pair of radially opposed chambers 420, 460; and a second pair of radially opposed chambers 462, 464. The plurality of fluid chambers 420, 460, 462, 464 are separated by portions of the cam follower 414. The pairs of fluid chambers 420, 460, 462, 464 are symmetrically arranged. The first pair of fluid chambers 420, 460 is arranged to be axially opposed to the second pair of fluid chambers 462, 464. The pairs of fluid chambers 420, 460, 462, 464 are arranged to provide a balanced relative movement between the cam follower 414 and the cam tracks 412, 451. The first pair of chambers 420, 460 comprises a pair of common inlets 422, 466 and a pair of exclusive respective outlets 424, 468. The second pair of chambers 462, 464 comprises a pair of common second inlets (not shown) and a pair of exclusive respective outlets (not shown). Although nopt shown, it will be appreciated that the second pair of fluid chambers 462, 464 communicates with a similar, symmetrical and axially aligned arrangement of inlets and outlets. The chambers 420, 460, 462, 464 rotate relative to the inlets 422, 466 such that the pairs of inlets 422, 466 are in sequential fluid communication with the respective pairs of chambers 420, 460, 462, 464. The outlets 424, 468, rotate with the respective chambers 420, 460, 462, 464. The device 410 is configured such that the inlets 422, 466, of the first pair of fluid chambers 420, 460 is open whilst the inlets of the second pair of fluid chambers 462, 464 are closed (and vice versa) as can be seen in Figures 47 to 53. The device 410 is configured such that the outlets 424, 468 of the first pair of fluid chambers 420, 460 are open whilst the outlets of the second pair of fluid chambers 462, 464 are closed (and vice versa) as can also be seen in Figures 47 to 53.

The stators 413, 415 are axially urged against the cam follower 414. The device

410 is configured such that rotation of the cam follower 414 with the inner member 446 urges the second stator 415 in a first axial direction corresponding to a first rotational position (e.g. to the left between Figures 47 and 53). Accordingly the second cam track wall means 452 and the second cam follower wall means 454 are maintained in sealing contact. Simultaneously the first stator 413 is urged in the same axial direction, maintaining contact with between the first cam track wall means 416 and the first cam follower wall means 418.

The first pair of fluid chambers 420, 460 are in compression during rotation at the first rotational position (from Figures 47 to 53); and the second pair of fluid chambers 462, 464 are in expansion, balanced with the first pair of fluid chambers 420, 460. Further rotation of the cam follower 414 with the inner member 446 moves the stators 413, 415 in a second axial direction corresponding to another rotational position (e.g. to the right during further rotation from the position of Figure 47 - not shown). Accordingly the first pair of fluid chambers 420, 460 are in compression during further rotation (not shown); and the second pair of fluid chambers 462, 464 are in expansion, balanced with the first pair of fluid chambers 420, 460. It will readily be appreciated, that such simultaneous expansion and compression of the respective pairs of fluid chambers 420, 460, 462, 464 is repeated sequentially and successively as the cam follower 414 rotates further.

The device 410 functions generally similarly to that of Figures 13 to 31 , with the stators 413, 415 being keyed to the outer member 442 and axially movable relative thereto. However, rather than the rotor 417 opening and closing the inlets 422, 460, the common inlets 422, 460 of the first pair of fluid chambers 420, 460 are sequentially opened and closed by the relative axial movement of the first stator 413. The stator 413 also sequentially opens closes the respective outlets 424, 468 (as the outlets 424, 468 sequentially rotate past the axially moving peaks of the waveform 430 of the first cam track 412).

It will be appreciated that any of the aforementioned apparatus may have other functions in addition to the mentioned functions, and that these functions may be performed by the same apparatus.

The applicant hereby discloses in isolation each individual feature described herein and any combination of two or more such features, to the extent that such features or combinations are capable of being carried out based on the present specification as a whole in the light of the common general knowledge of a person skilled in the art, irrespective of whether such features or combinations of features solve any problems disclosed herein, and without limitation to the scope of the claims. The applicant indicates that aspects of the present invention may consist of any such individual feature or combination of features. It should be understood that the embodiments described herein are merely exemplary and that various modifications may be made thereto without departing from the scope of the invention. For example, where an attribute or feature has been described in relation to a cam follower or track, it will be appreciated that the attribute or feature could be applied to the other of the cam follower or track. For example, where the cam follower is described as closing an inlet or outlet, in other embodiments the cam track may close the inlet or outlet.

Claims

1. A fluid transfer device comprising:

at least one fluid chamber disposed between the cam track and the cam follower;

a fluid inlet to the at least one fluid chamber; and

a fluid outlet from the at least one fluid chamber;

wherein at least one of the first cam track wall means and/or the first cam follower wall means comprises or provides a wave or waveform.

2. The device as claimed in claim 1 , wherein the device comprises a pump and/or a downhole device.

3. The device as claimed in claim 1 or 2, wherein the first cam follower wall means comprises or provides a first cam follower wave or waveform.

4. The device as claimed in any preceding claim, wherein the first cam track wall means comprises or provides a first cam track wave or waveform.

5. The device as claimed in any preceding claim, wherein each of the first cam follower wall means and the cam track wall means comprises a respective wave or waveform and the respective waves or waveforms are substantially the same.

6. The device as claimed in any of claims 1 to 4, wherein each of the first cam follower wall means and the cam track wall means comprises a respective wave or waveform and the respective waves or waveforms are substantially different.

7. The device as claimed in any preceding claim, wherein the cam track and/or the cam follower is/are coaxially arranged and the cam follower is configured to rotate about a central axis along a rotational path defined by the cam track.

8. The device as claimed in any preceding claim, wherein the device comprises a throughbore.

9. The device as claimed in any preceding claim, wherein the fluid comprises at least one of: a drilling fluid; a formation fluid; and/or an injection fluid.

10. The device as claimed in any preceding claim, wherein, in use, the first cam track wall means and first cam follower wall means selectively abut, strike, ride over or upon, slide relative to, and/or contact one another such as to form a seal therebetween.

1 1. The device as claimed in any preceding claim, wherein the cam follower and/or cam track is/are configured to selectively open and/or close the inlet/s and/or outlet/s according to a relative rotational position.

12. The device as claimed in any preceding claim, wherein a volume of the at least one fluid chamber volume is configured to vary in response to a rotation of the cam follower relative to the cam track.

13. The device as claimed in any preceding claim, wherein at least one of the cam follower and/or cam track is/are configured to open the inlet when a relative rotational position of the cam follower and cam track corresponds to a minimum volume of the at least one fluid chamber.

14. The device as claimed in any preceding claim, wherein at least one of the cam follower and/or cam track is/are configured to maintain the inlet open when there is relative rotation between the cam follower and the cam track such that the at least one fluid chamber volume is increasing.

15. The device as claimed in any preceding claim, wherein at least one of the cam follower and/or cam track is/are configured to maintain the inlet open when underpressure in the at least one fluid chamber is created or present such that fluid is drawn into the at least one fluid chamber through the inlet.

16. The device as claimed in any preceding claim, wherein at least one of the cam follower and/or cam track is/are configured to close the inlet when the relative rotational position of the cam follower and cam track corresponds to a maximum volume of the at least one fluid chamber.

17. The device as claimed in any preceding claim, wherein at least one of the cam follower and/or cam track is/are configured to maintain the inlet closed when there is relative rotation between the cam follower and the cam track such that the at least one fluid chamber volume is decreasing such that the inlet is closed when overpressure in the at least one fluid chamber is created or present.

18. The device as claimed in any preceding claim, wherein at least one of the cam follower and/or cam track is/are configured to close the outlet when a relative rotational position of the cam follower and cam track corresponds to a minimum volume of the at least one fluid chamber.

19. The device as claimed in any preceding claim, wherein at least one of the cam follower and/or cam track is/are configured to maintain the outlet closed when there is relative rotation between the cam follower and the cam track such that the at least one fluid chamber volume is increasing.

20. The device as claimed in any preceding claim, wherein the device comprises an outer member with an inner wall that defines an outer wall of the at least one fluid chamber.

21. The device as claimed in any preceding claim, wherein the device comprises an inner member, and wherein an outer wall of the inner member defines an inner wall of the at least one fluid chamber.

22. The device as claimed in claim 21 , wherein the inner member is configured to connect to an external apparatus, such as a toolstring, coiled tubing, tubular, slickline, wireline, motor or the like.

23. The device as claimed in claim 21 or 22, wherein the cam follower is rotatable with the inner member.

24. The device as claimed in any of claims 21 to 23, wherein the cam follower is axially moveable with the inner member.

25. The device as claimed in any of claims 21 to 24, wherein the cam follower is driven by the inner member.

26. The device as claimed in any preceding claim, wherein the cam track is relatively axially movable with respect to the cam follower so as to ensure axial contact between the first cam track wall means and the first cam follower wall means.

27. The device as claimed in any preceding claim, wherein the device is configured to transfer fluid substantially radially.

28. The device as claimed in any preceding claim, wherein the device is configured to transfer fluid substantially axially.

29. The device as claimed in any preceding claim, wherein the device comprises a plurality of fluid chambers substantially circumferentially and/or substantially axially arranged.

30. The device as claimed in claim 29, wherein the chambers comprise a common inlet and/or outlet.

31. The device as claimed in any preceding claim, wherein the device further comprises a second cam track wall means and the cam follower comprises a second cam follower wall means, and the second cam track wall means and second cam follower wall means face one another.

32. A method of transferring a fluid comprising:

providing a device comprising a cam track and a cam follower, wherein the cam track comprises a first cam track wall means, the cam follower comprises a first cam follower wall means, and the first cam track wall means and first cam follower wall means face one another, and wherein at least one of the first cam track wall means and/or the first cam follower wall means comprises or provides a wave or waveform; providing at least one fluid chamber between the cam track and the cam follower;

flowing a fluid into the at least one fluid chamber via a fluid inlet;

moving the cam follower relative to the cam track; and flowing the fluid out of the at least one fluid chamber via a fluid outlet.

33. The method as claimed in claim 32, wherein the method comprises varying the volume of the at least one fluid chamber according to a rotational position of the cam follower relative to the cam track.

34. The method as claimed in claim 32 or 33, the method comprises varying the at least one fluid chamber volume according to an axial position of the cam follower relative to the cam track.

35. The method as claimed in any of claims 32 to 34, wherein the method comprises pumping a fluid.

36. An apparatus comprising a plurality of devices as claimed in any of claims 1 to 31.

37. The apparatus of claim 36, wherein the plurality of devices comprises a plurality of similar devices, such as a plurality of pump devices.

38. The apparatus of claim 36 or 37, wherein the plurality of devices comprises a plurality of dissimilar devices, such as at least one motor and at least one pump.

39. The apparatus of any of claims 36 to 38, wherein the apparatus is configured to use an output of a first device as an input to a second device.