WO2010000414A1

WO2010000414A1 - Pump

Info

Publication number: WO2010000414A1
Application number: PCT/EP2009/004585
Authority: WO
Inventors: Peter Kustermann; Peter Muschalek; Alexander Manfred Schmid; Gunther Erich Schmid; Thomas Herrmann
Original assignee: Gardner Denver Thomas Gmbh
Priority date: 2008-07-04
Filing date: 2009-06-25
Publication date: 2010-01-07
Also published as: DE102008031450A1

Abstract

The invention concerns a pump comprising a housing (2), a working chamber (3) located in the housing (2) for the delivery of a fluid, an inlet channel (18) which is fluidically connected to the working chamber (3) for guiding the fluid into the working chamber (3), an outlet channel (19) which is fluidically connected to the working chamber (3) for guiding the fluid out of the working chamber (3), and a valve unit for controlling the flow of the fluid in the inlet channel (18) and/or the outlet channel (19), the valve unit comprising at least one valve (28) which comprises a sealing area (29) for sealing the valve (28) with respect to the housing (2), a valve disc (32) with a central longitudinal axis (35) that is movable between an open position and a closed position, and centering arms (33) which resil- iently connect the valve disc (32) to the sealing area (29) and extend about the central longitudinal axis (35) in a substantially helical manner.

Description

Pump

The invention concerns a pump and a valve unit for a pump.

A pump is used to deliver a fluid. In this disclosure, the term fluid refers to a medium to be delivered, such as a liquid, a gas or a liquid-gas mixture.

A multitude of pumps are known from prior art which are equipped with valves for controlling the inlet or outlet of fluids or for open- and closed loop control of the flow direction of fluids. In particular when delivering aggressive fluids, this may result in an impaired valve function after some time, which may require expensive repairs.

It is the object of the invention to create a pump which is equipped with a valve unit that works in a particularly reliable manner even when delivering aggressive fluids. Furthermore, a satisfactory sealing effect shall be achievable in the closed position. Another object of the invention is to create a corresponding valve unit for a pump.

These objects are achieved according to the invention by the features set forth in claims 1 and 16. The essence of the invention is that an actuatable valve disc is connected to a sealing area via resilient centering arms which extend in a substantially helical manner.

Further advantageous embodiments of the invention are set forth in the subclaims.

A preferred embodiment of the invention is hereinafter described by means of the enclosed drawing in which Fig. 1 shows a side view of an inventive pump;

Fig. 2 shows a cut through the pump shown in Fig. 1 along the line II-

II in Fig. 1 ;

Fig. 3 shows an enlarged view of the item marked with X in Fig. 2; and

Fig. 4 shows a plan view of the inventive valve unit which is also shown in a cut perspective in Figs. 2 and 3.

The inventive pump 1, which is intended to deliver a fluid, is hereinafter described by means of Figs. 1 to 4. In the present embodiment, the pump 1 is designed as a diaphragm pump. The invention may in general be imple- mented using positive displacement pumps and dynamic pumps.

The pump 1 has a multipart housing 2. In the housing 2, a variable- volume working chamber 3 is located which may also be referred to as pumping chamber and which is substantially closed. The working chamber 3 is de- limited towards the bottom by a flexible, thin- walled pumping diaphragm 4 which is actuatable and which is composed of a fluid-tight elastomer material. In the present embodiment, a drive or a motor 5, respectively, is provided for actuation of the pumping diaphragm 4. The fluid is delivered by actuating the pumping diaphragm 4 which causes the volume of the work- ing chamber 3 to change. The pump is substantially symmetrical to a vertical symmetry plane E.

The housing 2 further has a drive section 6 comprising an inner, substantially enclosed drive chamber 7. The drive chamber 7 is approximately cy- lindrical and is provided underneath the working chamber 3. On top of the drive section 6, a first lower valve disc 8 is arranged, with a second upper valve disc 9 being disposed on top of said lower valve disc 8. A housing cover 10 is mounted on the upper valve disc 9. The drive section 6, the valve discs 8, 9 and the housing cover 10 are joined together in a fluid-tight manner such as to form the housing 2. They are aligned with one another in a consecutive manner.

The motor 5, which is a known electric rotation motor in the present em- bodiment, is flange-connected to the drive section 6. The motor 5 has a horizontal drive shaft 11 which is drivable for rotation and extends into the drive chamber 6 where it is mounted for rotation. The drive shaft 11 extends approximately through the center of the drive chamber 7 and is intersected along its length by the symmetry plane E. Also located in the drive chamber 7 is an eccentric 12 which is attached to the drive shaft 11 in a non-rotational manner. An annular bearing body 53 is connected to the eccentric 12 and has a receptacle 13 which is open towards the top. Mounted in the receptacle 13 is a connecting rod 14 which is actively connected to the pumping diaphragm 4. The bearing body 53 and the eccentric 12 are located approximately in the center of the drive chamber 7 of the drive section 6 while the receptacle 13 and the connecting rod 14 are already provided above the actual drive chamber 7 in a corresponding connection opening of the drive section 6, the connection opening being open towards the top. The pumping diaphragm 4 is already disposed in the lower valve disc 8 above the drive section 6. The motor 5 may however also be designed differently. The motor may for example be a linear motor or a linear drive, respectively. The bearing body 53 is preferably a ball bearing. When the motor 5 is operated, the drive shaft 11 thereof is set in rotation which in turn causes the eccentric 12 to rotate about a horizontal axis. The rotation of the eccentric 12 is translated into a uniform reciprocating tilting movement of the bearing body 53. This in turn results in an approximately linear vertical axial movement of the pumping diaphragm 4 by way of the connecting rod 14 which is actuated by the bearing body 53, thus causing the volume of the working chamber 3 to change.

The pumping diaphragm 4 is formed like a circular disk and has a radially outer edge area 15 which is clamped between the drive section 6 and the lower valve disc 8 in a fluid-tight manner. A sealing bead 16 is formed along the edge area 15 of the pumping diaphragm 4 so as to improve sealing reliability. The pumping diaphragm 14 may however also be shaped differently. The pumping diaphragm 14 may for example have an oval shape.

The working chamber 3 is delimited towards the bottom by the pumping diaphragm 4 such as to prevent the fluid to be delivered from entering the drive section 6. The working chamber 3 is delimited towards the top by the lower valve disc 8. To this end, the lower valve disc 8 has a convex, bowl- shaped central area 17 relative to the pumping diaphragm 4 which is able to move towards or away from said central area 17. The working chamber 3 is delimited towards the sides by the pumping diaphragm 4 and the lower valve disc 8. When the pumping diaphragm 4 is in the upper actuating po- sition, the working chamber 3 has a minimum volume which approaches zero. When the pumping diaphragm 4 is in the lower actuating position on the other hand, the working chamber 3 has a maximum volume. Figs. 2 and 3 show the pumping diaphragm 4 in the upper actuating position thereof. An inlet channel 18 and an outlet channel 19 are located in the two valve discs 8, 9 which are fluidically connected to the working chamber 3 in the bowl-shaped area 17. Extending substantially in the vertical direction, the inlet channel 18 and the outlet channel 19 may be fluidically connected to each other via the working chamber 3. The fluid to be delivered may be fed to the working chamber 3 from outside in a known manner via the inlet channel 18 while the fluid may be discharged from the working chamber 3 to the outside via the outlet channel 19.

The inlet channel 18 is formed by a channel portion 20 formed in the upper valve disc 9 and by a channel portion 21 formed in the lower valve disc 8, wherein the two channel portions 20, 21 may be fluidically connected to each other. The upper channel portion 20 is formed by exactly one vertical bore and is fluidically connected to a horizontal feed line. The entry side of the feed line is connected to the channel portion 20. The lower channel portion 21 is formed by several, preferably three, identical vertical bores. Each of the bores has a circular cross-section, wherein the cross-section of the bore forming the channel portion 20 exceeds the cross-section of a bore forming the channel portion 21.

Furthermore, a cup-shaped receiving chamber 22, which is open towards the top, is formed in the lower valve disc 8, with a stop 23 projecting upwards centrally from the bottom of said receiving chamber 22. The central longitudinal axis of the stop 23 is substantially in line with the central lon- gitudinal axis of the upper channel portion 20. The central longitudinal axis of the stop 23 perpendicularly intersects the stop surface of the stop 23. The bores forming the lower channel portion 21 are disposed equidistantly about the stop 23. If three bores are provided, as in the present embodiment, these bores are arranged in the shape of an imaginary, substantially equilateral triangle, the stop 23 being located in the center thereof. It is also conceivable to provide more than three bores. These bores will then also be disposed equidistantly about the stop 23, with their respective centers being disposed about the central longitudinal axis of the stop 23 in a substantially concentric manner. Bores within the scope of this embodiment shall be understood as channel-type fluid connections. It is in particular not necessary for the bores to be formed by drilling. The term "bore" therefore also includes fluid connections formed by casting.

The outlet channel 19 is principally identical to the inlet channel 18. Reference is made to the above description. The outlet channel 19 is formed by a vertical channel portion 24 formed in the lower valve disc 8 and by a vertical channel portion 25 formed in the upper valve disc 9, wherein the two channel portions 24, 25 may be fluidically connected to one another. A cup-shaped receiving chamber 26 is however formed in the upper valve disc 9. Said receiving chamber 26 is open towards the bottom. A stop 27 projects centrally from the bottom of the receiving chamber 26, the central longitudinal axis of said stop 27 substantially being in line with the central longitudinal axis of the lower channel portion 24. The upper channel por- tion 25 is formed by several, in particular three, bores in the present embodiment while the lower channel portion 24 is formed by exactly one bore. The bores forming the upper channel portion 25 are disposed equidistantly about the stop 27. A horizontal outlet line 54 is connected to the outlet side of the upper channel portion 25 which is adjacent and parallel to the feed line.

A one-piece, plate-like valve unit for controlling the fluid flow in the inlet channel 18 and the outlet channel 19 is disposed between the lower valve disc 8 and the upper valve disc 9. The valve unit is symmetrical to the symmetry plane E. In the present embodiment, the valve unit is composed of an elastomer material and comprises two valves 28 which are principally identical.

Due to the identical design of the valves 28, the following is a detailed description of substantially only one valve 28. A valve 28 has a substantially annular, completely circumferential, radially outer sealing area 29 which in turn has a radially outer sealing bead 30 and a boundary portion 31 the inside of which is in contact with said sealing area 29. A central, approxi- mately circular valve disc 32 is directly connected to the inside of the annular boundary portion 31 by way of several movable centering arms 33. In this embodiment, three centering arms 33 are provided. The centering arms 33 are disposed equidistantly and are designed identically. The valve 28 also has three longitudinal fluid openings 34 which have an approximately angular shape in each case, may establish a fluid connection between the channel portions 20, 21 or 24, 25, respectively, of the respective channel 18 or 19, and are delimited by the boundary portion 31, the centering arms 33 and the valve disc 32. Each valve 28 has a central longitudinal axis 35 which passes through the center of the valve disc 32 disposed centrally in the sealing area 29, thus extending perpendicularly to a plane that passes through the valve unit and perpendicularly intersects the symmetry plane E. According to Fig. 3, the central longitudinal axis 35 extends in the vertical direction.

Extending about the central longitudinal axis 35 in a substantially helical manner, the centering arms 33 hold the valve disc 32 in the center of the sealing area 29. Furthermore, the centering arms 33 act as spring elements such that the valve disc 32 is resiliently movable. They have a prestress which will be described in more detail below. Each centering arm 33 has a thickened, short outer connecting portion 36 which is directly connected to the boundary portion 31 and extends substantially radially inwards form the inner free edge of the boundary portion 31. A longitudinal intermediate portion 37 adjoins said connecting portion 36, the intermediate portion 37 extending in the clockwise direction from the connecting portion 36 to the valve disc 32 in the valve 28 shown on the right-hand side of Fig. 4. Each centering arm 33 further has a short inner connecting portion 38 which is directly connected to the valve disc 32 by way of the outer edge thereof. The connecting portion 38 extends outwards from the valve disc 32 in a substantially radial direction. Starting from the connecting portion 36, the centering arm 33 extends into a curve 39 which eventually forms the intermediate portion 37. Said intermediate portion 37 then extends into a curve 40 which eventually forms the connecting portion 38. The curves 39, 40 are opposite to one another, each forming an angle of approximately 70° to 90°. The intermediate portion 37 runs approximately centrally between the outer edge of the valve disc 32 and the inner edge of the boundary portion 31 and extends about the central longitudinal axis 35 in an approximately concentric manner. The intermediate portion 37 has an approximately constant curve, with the central longitudinal axis 35 forming the center thereof. Each centering arm 33 is substantially configured in the shape of an "S" or an upside-down "S". The connecting portions 36, 38 and the intermediate portion 37 of a centering arm 33 are substantially surrounded by two adjacent fluid openings 34. The intermediate portions 37 are substantially tangential to the valve disc 32 or the boundary portion 31, respectively. The centering arms 33 are substantially tangential to the valve disc 32 and the boundary portion 31. They are connected to the valve disc 32 and the boundary portion 31 in a substantially tangential manner. According to the valve 28 shown on the left-hand side of Fig. 4, the centering arms 33 extend from the boundary portion 31 to the valve disc 32 in the anticlockwise direction. In all other respects, the valve 28 is substantially identical to the valve 28 described above.

On their outsides, the two valves 28 are connected to each other via their respective sealing beads 30 such that the complete valve unit has the shape of an "8" when seen from above, the valves 28 being superficially connected along a straight line which is intersected by the symmetry plane E. At this point, a common sealing bead 30 is provided which is adjoined on both sides by the boundary portions 31.

A respective receiving groove 41 or 42 extends in each of the valve discs 8 and 9, the receiving grooves 41, 42 being opposite to one another, thus forming a common stationary receptacle 43 for the sealing bead 30. According thereto, the receptacle 43 has a shape which corresponds to the shape of the sealing beads 30. The receptacle 43 therefore also has the shape of an "8". In the receptacle 43, the sealing beads 30 are pressed together in a stationary position to provide a sealing effect. The sealing beads 30 generally ensure that the pump 1 is sealed off from the outside. In the contact area between the two sealing beads 30 of the two valves 28, however, a sealing effect is achieved between the inlet channel 18 and the outlet channel 19. This area is intersected by the symmetry plane E.

Likewise, the boundary portions 31 adjoining the inside of the respective sealing bead 30 are also clamped immovably between the lower valve disc 8 and the upper valve disc 9. According to the right-hand half of Fig. 3, the lower valve disc 8 has an annular, projecting sealing nose 44 which is formed on the surface facing the valve disc 9. Completely surrounding the receiving chamber 22, the sealing nose 44 engages the corresponding boundary portion 31 of the respective valve 28 from below, thus deforming the boundary portion 31 such as to achieve a sealing effect. Opposite the sealing nose 44, a corresponding recess 45 is formed in the valve disc 9, serving as a receptacle for the material displaced by the sealing nose 44. The boundary portions 31 act as a boundary between the static sealing area of the valve 28 and the inner areas of the valve 28. The inner areas of the valve 28 include the centering arms 33 and the valve disc 32 while the static sealing area is substantially formed by the sealing bead 30.

The left-hand half of the valve discs 8, 9 according to Fig. 3 is formed in a similar manner. Reference is made to the above description thereof. In contrast thereto, a projecting annular sealing nose 46 is formed on the left-hand half of the upper valve disc 9 according to Fig. 3, with a corresponding re- cess 47 being formed opposite thereto in the lower valve disc 8. The sealing nose 46 is located on the surface of the upper valve disc 9 facing the lower valve disc 8. The sealing nose 46 and the recess 47 have a design which is equivalent to the design of the sealing nose 44 and the recess 45 described above. Their function is also identical.

The upper channel portion 20, the valve disc 32 assigned thereto and the stop 23 assigned to said valve disc 32 have a common central longitudinal axis which is denoted by the reference numeral 48. The valve disc 32 is movable along the central longitudinal axis 48. The central longitudinal axis 48 is in line with the central longitudinal axis 35 of the valve disc 32. In analogy thereto, the channel portion 24, the valve disc 32 assigned thereto and the stop 27 assigned to said valve disc 32 have a common central longitudinal axis which is denoted by the reference numeral 49 in this example. The respective valve disc 32 is movable along the central longi- tudinal axis 49. The central longitudinal axis 49 is in line with the central longitudinal axis 35 of the respective valve disc 32.

The following is a description of the function of the inventive pump 1. As already described, the pumping diaphragm 4 may be actuated by the motor 5. An actuation of the pumping diaphragm 4 causes the volume of the working chamber 3 to change, with the result that a fluid to be delivered is drawn into the working chamber 3 via the feed line and the inlet channel 18 and is discharged afterwards via the outlet channel 19 and the outlet line 54. The valves 28 are actuated by the changing volume of the working chamber 3, which means they are substantially self- actuated, with the valves 28 being movable between an open position and a closed position. According to Fig. 3, the valve 28 disposed in the inlet channel 18 is in its closed position in which the valve disc 32 completely shuts off the channel portion 20. Thus, the valve disc 32 completely covers the lower outlet 50 of the channel portion 20 and is in sealing contact with the upper valve disc 9 via the contact portion 51 thereof which surrounds the outlet 50 while facing downwards. When the valve 28 is in this position, a backflow of fluid from the working chamber 3 or the channel portion 21 , respectively, into the channel portion 20 is not possible.

According to Fig. 3, the valve 28 disposed in the outlet channel 19 on the other hand is in its open position in which the valve disc 32 is lifted off the respective contact portion 53 of the lower valve disc 8. The surface of the valve disc 32 is thus in contact with the respective stop 27 which restricts the opening movement of the valve disc 32. The stops 23, 27 are designed such as to prevent the valve discs 32 from adhering thereto when in their open position. When the valve 28 is in the open position, the fluid may pass through the outlet channel 19 via the valve 28, thus flowing from the channel portion 24 into the channel portion 25 through the fluid openings 34 in the respective valve 28. The equidistantly disposed fluid openings 34 provide for an even flow distribution in the vicinity of the valve disc 32.

The receiving chambers 22, 26 provide a sufficient amount of space for the centering arms 33 to allow for a movement of the valve discs 32. The centering arms 33 are prestressed such that the valve discs 32 are always forced into their closed position. Thus when the pumping diaphragm 4 is no longer actuated, the valve discs 32 automatically revert back to their closed position. During the operation, the valves 28 are actuated in an alternating manner, with the result that one valve 28 is in its open position while the other valve 28 is in its closed position and vice versa substantially throughout the entire operation. The valve 28 shown on the right- hand side of Fig. 3 is movable from its upper closed position to a lower open position while the valve 28 shown on the left-hand side of Fig. 3 is movable from its lower closed position to an upper open position. The stops 23, 27 restrict the opening paths, opposite to one another, of the valves 28.

An expansion of the elastomer material of the valve unit during the delivery of the fluid results in a defined deformation of the inner areas of the valve 28 caused by elongation or rotation, respectively, of the helical centering arms 33. An elongation of the centering arms 33 in particular causes the valve disc 32 to be rotated about the central longitudinal axis 35. The rotational movement of the valve disc 32 is due to the substantially tangential position of the centering arms 33 relative to the respective valve disc 32 and the respective boundary portion 31.The prestress of the centering arms 33 is maintained despite the rotational movement. The symmetrical design of the valve unit enables said valve unit to be mounted in the housing 2 in any desired position.

In an alternative embodiment, the valve unit has exactly one valve 28 or more than two valves 28, more specifically three, four, five, six... valves 28. Said valves 28 are then connected such as to form one piece. The valves 28 may however also be formed separately.

Likewise, it is also conceivable to provide two or more than three centering arms 33. A symmetrical arrangement thereof is advantageous in terms of fluid flow.

In an alternative embodiment, the inlet channel 18 is equipped with only one valve 28. In another embodiment, the outlet channel 19 is equipped with only one valve 28. This results in a corresponding shape of the valve unit which approximately resembles an "O". The other channel 19 or 18, respectively, is then not equipped with a valve 28.

Claims

1. Pump comprising a) a housing (2); b) a working chamber (3) located in the housing (2) for delivery of a fluid; c) an inlet channel (18) which is fluidically connected to the working chamber (3) for guiding the fluid into the working chamber (3); d) an outlet channel (19) which is fluidically connected to the work- ing chamber (3) for guiding the fluid out of the working chamber

(3); e) a valve unit for controlling the flow of the fluid in the inlet channel (18) and/or the outlet channel (19), the valve unit comprising at least one valve (28) which comprises i. a sealing area (29) for sealing the valve (28) with respect to the housing (2); ii. a valve disc (32) with a central longitudinal axis (35), the valve disc (32) being movable between an open position and a closed position; and iii. centering arms (33) which resiliently connect the valve disc (32) to the sealing area (29); and extend about the central longitudinal axis (35) in a substantially helical manner.

2. Pump according to claim 1 , characterized in that the at least one valve (28) is composed of an elastomer material.

3. Pump according to claim 1 or 2, characterized in that one valve (28) is located in the inlet channel (28).

4. Pump according to one of the above claims, characterized in that one valve (28) is located in the outlet channel (19).

5. Pump according to one of the above claims, characterized in that the valve unit comprises two valves (28) which are formed in one piece.

6. Pump according to claim 5, characterized in that the valves (28) are connected to one another by way of their sealing area (29).

7. Pump according to claim 5 or 6, characterized in that the valve unit substantially has the shape of an "8".

8. Pump according to one of claims 5 to 7, characterized in that one valve (28) is located in the inlet channel (18) and one valve (28) is located in the outlet channel (19).

9. Pump according to one of the above claims, characterized in that the sealing area (29) has a circumferential sealing bead (30).

10. Pump according to claim 9, characterized in that the sealing area (29) has a boundary portion (31) which is provided between the sealing bead (30) and the centering arms (33).

1 1. Pump according to claim 10, characterized in that a sealing nose (44, 46) of the housing (2) engages with the boundary portion (31).

12. Pump according to one of the above claims, characterized in that the centering arms (33) are prestressed so as to force the valve disc (32) into the closed position.

13. Pump according to claim 12, characterized in that the valve unit is designed such that an expansion thereof only causes the valve disc (32) to rotate.

14. Pump according to one of the above claims, characterized in that the centering arms (33) are substantially tangential to the valve disc (32) and/or the boundary portion (31).

15. Pump according to one of the above claims, characterized by a stop (23, 27) for the valve disc (32) in the open position.

16. Valve unit for controlling the flow of a fluid in an inlet channel (18) and/or an outlet channel (19) of a pump (1), wherein the valve unit comprises at least one valve (28) which comprises a) a sealing area (29) for sealing the valve (28) with respect to a hous- ing (2) of the pump ( 1 ); b) a valve disc (32) with a central longitudinal axis (35), the valve disc (32) being movable between an open position and a closed position; and c) centering arms (33) which i. resiliently connect the valve disc (32) to the sealing area (29); and ii. extend about the central longitudinal axis (35) in a substantially helical manner.