US3647324A

US3647324A - Electrically driven pumps capable of use as heart pumps

Info

Publication number: US3647324A
Application number: US886137A
Authority: US
Inventors: Edson Howard Rafferty; Harold D Kletschka
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-12-18
Filing date: 1969-12-18
Publication date: 1972-03-07
Anticipated expiration: 1989-03-07

Abstract

Pumps capable of use as heart pumps; that is, for pumping blood in connection with the maintenance of the life function in a human or animal body to replace one or more pumping functions of the heart. The pumps are also useful for pumping kidney fluids. The pumps herein described are electrically driven, that is, they are driven by assemblies which function as electric motors.

Description

- United States Patent Rafferty et a1.

[ 51 Mar. 7, 1972 [54] ELECTRICALLY DRIVEN PUMPS CAPABLE OF USE AS'HEART PUMPS [72] Inventors: Edson Howard Rafferty, 151 2nd Avenue, Excelsior, Minn. 55331; Harold D. Kletschka, 4321 Woodley Square 0140, Montgomery, Ala. 361 11 22 Filed: Dec. 18,1969

211 Appl. No.: 886,137

Related u.s. Application um [63] Continuation-impart of Ser. No. 678,265, Oct. 26,

1967, Pat. No. 3,487,784.

[52] US. Cl...; ..4l7/420, 310/156 [5 1] Int. Cl. ..F04b 17/00, F04b 35/04, H021: 21/12 [58] Field of Search ..4l7/420, 423, 424, 406;

[56] References Cited UNITED STATES PATENTS Primary Examiner-Robert M. Walker Attorney-Carl B. Fox, in

[57] ABSTRACT Pumps capable of use as heart pumps; that is, for pumping blood in connection with the maintenance of the life function in a human or animal body to replace one or more pumping functions of the heart. The pumps are also useful for pumping 'kidney fluids. The pumps herein described are electrically driven, that is, they are driven by assemblies which function as electric motors.

10 Claims, 15 Drawing Figures PATENTEUHAR 7 m2 3,547, 324

sum

1 or 3 5060/? Howard fiaffer/y ATTORNEY PATENTEDMAR 71972 3, 547, 324

SHEET 2 OF 3 QMZ ELECTRICALLY DRIVEN PUMPS CAPABLE OF USE AS HEART PUMPS This application is a continuation-in-part of application Ser. No. 678,265, filed Oct. 26, 1967, by the same inventors and entitled Pumps Capable of Use As Heart Pumps," on which application US. Pat. No. 3,487,784 issued on Jan. 6, I960.

BACKGROUND OF THE INVENTION Field of the Invention The field of the invention is the field relating to apparatus for pumping blood of a living person, or of a living animal, to

replace one or more pumping functions of the human or being pumped. The pumps do not impose sudden pressure changes, impacts, rapid changes in direction of flow, in order to prevent injury to or destruction of the pumped material and its components. Various electrical drive assemblies are provided according to the invention for motivating or rotating the rotators employed in the pumps.

DESCRIPTION OF THE PRIOR ART In the prior art, artificial heart pumps heretofore employed have been of the positive displacement type. Because of the relatively delicate nature and structure of blood, and of other body fluids such as the fluids flow through the kidney, it has been found that use of centrifugal pumps invariably results in physical disruption of the blood or other fluid or of at least some of their components. Although it has been shown that a pulsating movement of blood through the body is not necessary to sustain life, the prior art has not afforded a solution to the. problems involved in utilization of centrifugal pumps for pumping blood, since at least partial destruction of the blood has always resulted when centrifugal pumps were used. This invention solves these problems, by providing rotative pumping means for pumping blood, or for pumping kidney fluids, without any significant destruction of the blood or other fluid and their components resulting from the pumping.

SUMMARY OF THE INVENTION The invention is of rotative pumps which are electrically driven, i.e., by electric motors, or the like, which are suitable for use in pumping blood or other fluid for circulation through the body passages, veins, arteries, etc., of a living person or animal.

The pumps are adaptable for use disposed within a body cavity, for example as replacements for either or both of the pumping functions of the heart. The pumps herein provided may also be used for pumping blood externally of the body. The pumps are adapted to pump without producing severe pressure changes, physical impacts, and the like, so that none of the blood components is subjected to treatment which will destroy it for use. The pumps do not require the use of valves, such as those of the heart, but valves may be provided ifdesired.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partial view indicating a preferred form of pump having a built-in drive motor for the accelerator or rotator of the pump.

FIG. 2 is an axial cross-sectional view of another form of pump having a built-in drive motor for the accelerator or rotator assembly of the pump.

FIG. 3 is a vertical cross-sectional view taken at line 3-3 of FIG. 2.

FIG. 4 is an axial cross-sectional view showing still another form of pump according to the invention.

FIG. 5 is a partial cross-sectional view taken at line 5-5 of FIG. 4.

FIG. 6 is an axial cross-sectional view showing another form of pump according to the invention.

FIG. 7 is a perspective view showing a modified form of ac celerator or rotator useful in pumps according to the invention.

FIG. 8 is an elevational view of the apparatus shown in FIG. 7, taken from the right hand of the apparatus of FIG. 7.

FIG. 9 shows another modified form of accelerator or rotatOl'.

FIGS. l015 show six additional forms of accelerators or rotators useful in the pumps according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Blood is a complex and delicate fluid. It is essentially made up of plasma, a pale yellow liquid containing microscopic materials including the red corpuscles (erythrocytes), white corpuscles (leukocytes), and platelets (thrombocytes). These and the other constituents of blood, as well as the nature of suspension of these materials in blood, are fairly readily affected by the manner in which blood is physically handled or treated. Blood subjected to mechanical shear, to impact, to depressurization, or the like, may be seriously damaged. The balance between the blood constituents may be affected. Commencement of deterioration may result from physical mishandling of blood. Blood which has been damaged may be unfit for use.

The heart pumps blood through the body in a circulating, cyclic, fashion. The blood passes repeatedly through the heart. A pump for replacing one or more pumping functions of the heart should therefore be capable of repeatedly pumping the same blood, time and time again, without damaging the blood, at least not more than to the extent where the body can function to repair or replace the blood components and eliminate damaged and waste materials therefrom.

Blood also contains dissolved and chemically combined gases, which may be seriously affected by improper physical handling of the blood. It has, for example, been established that subjecting blood to negative or subatmospheric pressures of, say, minus 300 millimeters of mercury, is detrimental, even when the reduced pressures are only temporary.

The blood pressure is the pressure of the blood on the walls of the arteries, and is dependent on the energy of the heart action, the elasticity of the walls of the arteries, the peripheral resistance in the capillaries, and the volume and viscosity of the blood. The maximum pressure occurs at the time of the systole of the left ventricle of the heart and is termed maximum or systolic pressure. The normal systolic pressure may be from about millimeters of mercury (mm. Hg) to about I50 mm. Hg, the pressure ordinarily increasing with increasing age. Pressures somewhat outside this range are not uncommon. The minimum pressure is felt at the diastole of the ventricle and is termed minimum or diastolic pressure. The diastolic pressure is usually about 30 to 50 mm. Hg lower than the systolic pressure.

The preferred embodiments of the invention shown and described have in common that the blood or other delicate fluid is handled gently, without shear, shock, vibration, impact, severe pressure or temperature change, or any other condition or treatment which would unduly damage the blood or other fluid. Essentially nonturbulent flow is accelerated gradually and smoothly.

The pumping action obtained may be described as radially increasing pressure gradient pumping, or in some cases more specifically as forced vortex radially increasing pressure gradient pumping. In centrifugal pumps, the fluid acted on by the vanes of the impeller is positively driven or thrown outwardly (radially) by the vane rotation. The fluid as it moves from the vanes to the ring-shaped volute space beyond the tips of the vanes is reduced in velocity, and as the velocity decreases the pressure increases according to Bernoullis theorum. On the other hand, in the pumps provided according to this invention, the pumped fluid is not driven or thrust outwardly but instead is accelerated to circulate in the pumping chamber at increasing speeds as it moves farther and farther from the center. At the outer periphery of the accelerator or rotator, the speed of the fluid is maximum.

The action of the fluid in the pumps may be clarified by analogy to a glass of water turning about its vertical axis without sideways motion or wobble. Because of its contact with the sides and the inherent potential shear force of the water in the glass, the water will rotate, in the form of a forced vortex, without much slip or shear between radially adjacent particles of water, and the water radially away from the center of rotation will be moving faster than water nearer the center. If water is introduced through a tube at the axis of the glass and water is removed through one or more holes through the side of the glass, water will be pumped by the rotation of the glass. In the pumps afforded by this invention, while rotators are provided, in a number of different forms, the rotators are designed such that they act to increase the swirling speed of the liquid passing through the pump, but do not act to drive or throw the liquid toward the periphery or volute of the pump chamber, but instead only increase the rotational speed of the liquid. As the rotative speed of the liquid is increased, it achieves a higher orbit about the center of the accelerator and moves toward the periphery of the chamber.

In each case, the pumps are provided with internal driving means in the form of an electric motor drive of some form. The electrical parts of the electrical motor drives are presented in several different forms as will be later further described.

Referring first to FIG. 1 of the drawings, a pump rotator is shown which has a plate or disc 21 at each of its sides, which may be identical or of different forms or sizes, only one being shown in the drawing, and between which there are provided the equally circularly spaced curved blades 23a-23h, each curved from its inner end to its outer end as shown and each having a twist throughout its length similar to the twist of the propeller. The blades or vanes may extend beyond the outer edges of the disc 21. Each blade 23a-23h has therearound a winding 24, which is covered by an impervious layer or membrane 25. The blade windings are connected to contact elements of a commutator 27. The surrounding pump housing is provided with the circularly spaced magnets or coils 28, which are separated from the pumping chamber by an impervious layer or membrane 29. The commutator rotates with the rotator in the usual manner of an electric motor. The rotator windings and housing magnets or coils constitute an internal electric motor for driving the rotator to pump fluid. The electric motor thus provided may be of any of the known types,

AC or DC, with or without commutation, powered by electrical conductors leading thereto'from any suitable AC power source or from a battery, located either internally or externally of the body. The conductors may be disposed through the outer body wall from the exterior of the body, installed surgically. The power source may include capacitance connections across the body wall, with both of its plates beneath the skin, or with one plate interior of the skin and the other exterior of the skin. A battery power source may be disposed within the body, and replaced periodically by surgery, or recharged inductively from the exterior of the body. Batteries capable of operation for periods in excess of one year are available so that surgery for their replacement would need to be done either annually or at longer intervals.

While the self-contained drive motor is herein shown and described in connection with the form of rotator shown in FIG. 1, it will be understood that it may be provided in conjunction with other forms of rotators disclosed herein or in said U.S. Pat. No. 3,487,784. Teflon may be used for the

membranes

25 and 29 covering the windings of the electric motorstructures.

Accelerator or rotator 20 may be mounted for rotation.

within any suitable pumping chamber or housing. The chamber or housing is not shown in FIG. 1 of the drawings. Fluid entering the pumping chamber adjacent the shaft 30 on which rotator 20 is mounted is moved circularly by the vanes of the rotator to move progressively toward the outer center 42 which is connected to a shaft or rod 43 which is rotatively disposed through an opening of housing end portion 45. Housing portion 45 is inwardly curved corresponding to the curvature of vane 37 and the vane is spaced therefrom as shown. The smaller end of vane 35 outwardly of opening 39 thereof is rotatively sealed within the housing 48 by a circular seal 49, for example, an O-ring, and a bearing 50 is provided adjacent the seal. Housing 48 is inwardly curved corresponding to the curvature of the vane 35.

v The three vanes rotate together when driven in rotation as will be described. The vanes 35-37 are each permanently magnetized to have alternate magnetic north and south poles N and S" spaced therearound as indicated in FIG. 3 by

reference numerals

51, 52, respectively, of vane 36. The other two vanes have magnetic poles therearound in positions corresponding to the pole positions shown for vane 36. The windings of the electrical motor assembly are indicated by reference numeral 54, and are disposed within housing 48 around the outside of the outer edges of vanes 35-37. Separate magnets may be connected to the vanes, instead of the vanes being magnetized, if desired.

Housing 48, at its left-hand end as shown in FIG. 2, is inwardly and outwardly curved corresponding to the curvature of vane 35. An inwardly projecting thickened wall portion 55 surrounds the fluid inlet to the pump. Portion 45 of the housing is, as has been described, inwardly curved corresponding to the curvature of vane 37, and is flat at its outer side. The surrounding portion 57 of the housing wall has winding 54 disposed therein and extends around the outer edges of the vanes, and is spaced outwardly uniformly therefrom. The inner surface of wall 57 has a pair of circular bevelled-sided annular projections 59, 60 which are centered between the

vanes

35, 36 and 36, 37 respectively.

The electrical switching elements for the windings 54 are disposed inside of housing portion 45 at 62. The rod 43 is journaled through bearing 63 and serves to rotate the necessary switching elements at 62. The switching elements 62 are connected to the windings in customary fashion, these connections not being shown in the drawings because they are of standard conventional form in order that the winding currents may be alternated as required for the apparatus to perform its rotative motive function. An electric power source for the drive motor is provided and is connected to leads 64, 65, the power source being of any convenient nature. When electrical current is supplied to the windings through switching elements 62, the magnetic rotators rotate. Fluid enters the pump through the opening within thickened wall portion 55 and flows between

vanes

35 and 36 and between

vanes

36 and 37, reaching these areas through

vane openings

39 and 40. Since there are no rotator surfaces to directly force the fluid radially outwardly, as in a conventional centrifugal pump, friction between the vanes and the fluid causes the fluid to commence circulating round and round in circular fashion, and gradually moving outwardly toward the pumping chamber periphery. The housing has an outlet 64 shown to be more or less tangential of the chamber periphery, but which may be directed in any flow direction from the chamber. Fluid the velocity of which has been increased by rotations of the vanes is caused to move under pressure out of outlet 64 to accomplish the pumping function of the pump. Arrow 65 indicates the direction of rotator rotations.

Referring now to FIGS. 4 and 5 of the drawings, the housing is of the same general form as housing 48 of FIGS. 2 and 3. A plurality of vanes 71-74 are disposed within the pumping chamber, the outermost vane 71 being rotatively sealed by a circular seal 76, for example, an O-ring, and journaled in a suitable ring bearing. The housing has a thickened wall portion 77 around the fluid inlet to the pump and the successive vanes 71-74 have progressively smaller circular flow passages 78-81 affording fluid flow to between the spaced apart vanes. The vanes are connected by circularly spaced elements 83 to a rotating magnet body 84. Body 84 carries a concentric shaft 85 which is journaled in bearing 86. The end 87 of magnet body 84 is flaringly curved corresponding to the curvature of vane 74 and is spaced therefrom by a distance about equal to the vane spacings. Magnet body 84 has therearound alternating north and south poles permanently magnetized therein, similarly to the magnetic poles of the vanes 35-37 of FIGS. 1 and 2. The connection elements 83 are of streamlined cross section as is best shown in FIG. 5. The vanes are larger and rounded at one edge and tapered to a thin edge 89 at their opposite sides. The rounded edges 88 of the elements 83 are the leading edges which are impelled through the fluid being pumped and the shapes of the elements provide streamline flow therearound whereby turbulence is not caused by the elements 83. The pump of FIGS. 4-5 has imbedded in housing 70 the windings 89 similarly as .the windings 54 are provided in FIGS. 1-2. The electrical switching elements for the windings are disposed in a chamber 91 which is provided at the end of rod or shaft 85. The electrical connections between the switchings elements and the windings are not shown as they are conventional in nature. Electrical power is supplied through

electrical leads

92, 93, from a suitable power supply,

not shown.

Referring now to FIG. 6 of the drawings there is shown a motor-pump structure having a partitioned housing, the rotator elements being disposed within one chamber of the housing and the magnetic armature element being disposed in a separate chamber. The housing of the pump shown in FIG. 6 is circularly and curvingly flared at end 101, inwardly and outwardly. A thickened wall portion 102 surrounds the circular fluid inlet to the pump. A circular flared vane 103 is sealed and journaled to the pump housing at 104. A rotative vane member 105 is circularly and flaringly fonned and spaced from vane 103. The opposite side 106 of vane 105 is circular and flat as shown. The vanes are connected together by a plurality of circularly spaced rods 108. A rod or shaft 109 is concentrically connected to vane member 105 and is journaled through bearings 110, 111. At its other end, rod or shaft 109 carries a circular disc magnet 113 having spaced therearound alternating north and south poles of permanent magnetism as previously described for the other embodiments. The magnetic disc 113 is affixed flatly against a thicker disc 114 which rotates therewith. Rod 109 extends into a terminal bearing 115. Housing 100 is flat at its end 117. A chamber 119 formed on the end 117 of the housing contains the electrical switch elements for the motor winding 120 which is disposed as before within a circular annular chamber of the housing, outwardly surrounding the magnetic disc 113. Upon supply of electrical power to the motor windings 120 through the switching elements 119, the magnetic disc 113, disc 114 connected therewith, and the

rotator elements

103, 105 rotateto pump fluid entering through the passage within thickened wall portion 102 to flow within vane 103 and outside of vane 105. The pump, again, has no impeller surfaces causing fluid thrust radially outwardly within the pumping chamber so that the fluid is caused to rotate circularly with constantly increasing radius, to be expelled through outlet 124 from the housing. The outlet 124 may be designed similar to outlet 64 of the FIG. 2-3 embodiment.

In FIGS. 7-8, and FIGS. 9-15, there are shown various forms which the rotators or accelerators for pumping of the fluid may take. The rotators are shown more or less schematically in the drawings. In FIG. 7, two circularly flared pumping

rotators

130, 131 are connected by spiral shaped

connectors

132, 133 and 134, with vane or rotator rotation in the direction indicated by arrow 135. The spiral connectors 132-134 serve to institute circular flow of the fluid passing between the vanes as the fluid enters through opening 137. The vane rotation causes the fluid to flow in increasing radius circles to exit at 138, the circular space between the outer vane edges.

In FIG. 9, there is shown a rotator assembly including trumpet shaped circular flared

rotators

141, 142 which are connected by a connector 143 of the form of an increasing amplitudes screw formation. As fluid entering between the rotators at opening 144 of vane 141 is brought into contact with connector element 143, the screw shape of the connector impels the fluid to circular flow, the flow continuing outwardly between

vanes

141, 142 to exit from therebetween at 145.

The vanes in FIGS. 10-15 are of various shapes to indicate rotator surfaces which are useful in circularly impelling the fluid for pumping within a pump of the type herein described, the respective pumping chambers (not shown) being of corresponding interior shape. In FIG. 10 the

vanes

161, 162 are respectively of trumpet shape, circularly flared, vane 161 having an inlet opening 163, and fluid is caused by friction with the vanes to move in circles of increasing radius to exit finally between the outer vane edges at 164. In FIG. 11 the vanes are of hemispherical hollow form, the outer vane 171 having an inlet opening 172, and the vane 173 being of continuous spherical shape. In each case, the vanes are connected together by appropriate rods or other connector elements such as have been described. The vanes are mounted within a pumping chamber with appropriate seals and bearing surfaces around the flow inlet and with appropriate supports for suitable rotations of the vanes.

Referring now to FIG. 12, the vanes shown are of inconstant curvature, the vane 181 having a cylindrical tubular inlet 182 and the vane 183 having a more or less pointed formation 84 to direct the circularly moving fluid to between the vanes without friction, the fluid entering at 185 and exiting at 186. In F IG.'13 vane 191 is of truncated conical form, having an inlet at its apex 192, and the vane 193 being of conical form. Fluid enters at 194 and is expelled at 195.

The vanes 191a and 193a are similar to those shown in FIG. 13, except that the conical angle of vane 193a is flatter than the conical angle of vane 191a, and the vanes are of the same outer diameter, as shown. In FIG. 15, there are shown three vanes which are of the circular flared form heretofore encountered, each vane being thin walled at its

inner portion

201, 202 and 203, respectively, and relatively thicker walled at its outer

radial portion

201a, 202a, and 2030, respectively.

It will be noted that in all of the embodiments shown and described, the fluid inlet through the housing wall and the initial vane into the interior of which the fluid passes, are smoothly merged so that there are not abrupt changes of fluid flow therepast. In each case, the fluid to be pumped flows inwardly between rotating accelerator vanes or rotators, to be driven by friction with the rotators in a circular flow direction. The pumps operate on a forced vortex principal, there being no impeller surfaces in the pumps for impelling blood or other fluid material being pumped radially outwardly toward the periphery of the pump chamber. A forced vortex pump operates on the principal that a rotating chamber causes rotation of its contents, with creation of a vortex, so that a body of circulating fluid is maintained within the pump chamber by rotation of the rotator vanes at opposite sides of the chamber. The rotational speed of liquid in the pump is increased from the center to the periphery of the pumping chamber. The liquid is withdrawn at the peripheries of the vanes.

It will be seen that the blood or other fluid, such as fluids to be pumped through an artificial kidney utilizing the pumps, is

not submitted to any substantial agitation by the rotation of the vanes, or by any other portion of the pump apparatus. There are no sudden changes in direction of flow through the pumps, all joints between surfaces being smooth and all surfaces over which the fluid flows being smooth. Where there are more than two vanes, there are more than two spaces in which the fluid is rotated and pumped. According to this invention, the emphasis is on gentle, nonturbulent handling of the pumped fluid, as is illustrated by the aforementioned rotating glass of water with nothing to rotationally accelerate the water but the smooth side of the glass. Yet, the water after a time rotates with the glass and continues the rotation as long as the glass continues to rotate.

It will be realized that pumps may be supplied according to the invention with any number of pumping stages, and may include individual pumping stages of any of the types mentioned herein, and in any combination.

In the case of each of the pumps and rotators shown in the drawings, it will be noted that the rotators are designed to avoid turbulence and to avoid rapid pressuring and depressuring of the blood or other fluid, such as kidney fluid, being pumped, and also to avoid any physical grinding or abrasive action upon the fluid. As has been made clear, these rotator designs are made in this manner in order that blood or other delicate liquids or gasses being pumped, some containing solids in suspension, will not suffer detriment and will not be destroyed by the pumping operation.

In contrast to centrifugal pumps, the revolution speeds permitted of the rotators employed with the pumps herein shown and described are kept minimal. The several rotator designs presented are each of a form adapted to progressively increase the circular fluid velocities as the rotator turns and as the fluid advances toward the periphery of the rotator. In each pump presented, an annular fluid circulation space is provided which is entirely unobstructed and regular so that fluid can circulate therein without turbulence or baffle effects.

Referring to FIGS. 2 and 3 of the drawings, the plural rods 38 spaced about the vanes can be eliminated and the

rotators

35 and 36 levitated within the electromagnetic field generated by the windings of the electrical motor assembly indicated by reference numeral 54. The rod 43 can also be eliminated and all

rotators

35, 36, and 37 would then be levitated in the electromagnetic field generated by the windings of the electrical motor assembly 54. The levitated

rotators

35, 36, and 37 can all revolve at the same speed of rotation or each can revolve at a rotational speed independent of the others. Plural rods 38 or connecting elements 83 (this latter illustrated in FIG. may be used to join two or more rotators while the rotators are levitated in the electromagnetic field generated by the electrical motor assembly 54. In instances in which multiple rotators are levitated in an electromagnetic field, two or more rotators may be connected by plural rods 38 (illustrated in FIG. 3) or connection elements 83 (illustrated in FIG. 5) while one or more additional rotators are levitated and revolve without being connected to a neighboring rotator. It is understood that operation and levitation of the rotators within an electromagnetic field as described can be applied to the various forms of rotators disclosed herein or in said US. Pat. No. 3,487,784.

As hereinbefore indicated, pumps may be made according to the invention incorporating features from one or more of the preferred embodiments shown and described herein, any particular feature not being confined to use only with the other features in connection with which it is herein shown and described.

The pumps and their parts may be constructed of any materials compatible with their intended use, including metals, mineral materials, plastics, rubbers, wood, or other suitable materials. When blood is to be pumped, consideration must be given to biological compatibility so that trauma to the blood will not result. Teflon has been successfully used in contact with blood, without traumatic effects, and may be used in construction of the pumps for blood pumping adaptations. Noncorrosive metals and alloys may be used in the pumps where required.

The housings and rotators may be constructed of suitable material so that the housing may be rigid, semirigid, or elastic in whole or in part. The nonrigid constructions can be used for imparting pulse configurations to blood in heart simulation pumps.

While the rotators shown herein may in some cases perform better when rotated in one direction, it should be understood that they may be rotated in either direction i.e., reversed, without other modification of the pumps. Each of the rotators presents surfaces to the fluid being pumped, to cause accelerating circular fluid motion in the pumping chamber. In some cases, the surfaces are parallel to the fluid flow; in other cases parallel and nonparallel surfaces are provided. Each of these surfaces, of whatever form, will accelerate the fluid regardless of the direction of rotation of the rotator. Each rotator should be rotated at a speed such that essentially no fluid turbulence occurs, and differences in the rotator designs affects the maximum speed at which a particular rotator may be rotated. The physical and flow properties of the fluid pumped will, of course, also affect the maximum speeds of rotation at which the rotators may be operated without turbulence and other objectionable effects, such as cavitation, vapor binding, and the like. It is, therefore, not possible to set forth exact rotational speed ranges for the rotators. But, the speeds of rotation will always be lower and will usually be substantially lower than those of centrifugal pumps and blowers, wherein turbulence always occurs as the impellers thrust the fluid radially outwardly against the periphery of the pumping chamber, and those of the aforementioned multiple disc pumps and compressors. To the end of achieving reduced rotator speeds, pumps provided according to this invention may be of larger size than other pumps, for the same pumping capacity. As internally placed heart pumps, the pumps may be as large as 5 inches in diameter, and, with removal of a lung, even larger.

According to the precepts of this invention, the forms of the rotators may vary considerably. For example, the rotators may be constructed entirely or partly of porous or perforate materials, i.e., the vanes of the rotator which accelerate the fluid circularly may be made of screen, of perforate plates or sheets, of spaced rods, or the like, and will still ably perform their fluid accelerating function. Rotators may be of axially extended form, so that the fluid is accelerated axially or axially and radially. Designs of this nature would extend the flowpath from inlet to outlet so that acceleration would be at a slower rate. In each of the pumps shown and/or described, one or more tangential outlets could be provided, disposed in the direction of fluid flow inside the peripheral wall of the pump. In multistage pumps, the several rotators, which may be alike or unlike, may be driven at different rotational speeds. The axes of multistage rotators may be oflset and in other positions out of alignment.

While preferred embodiments of apparatus according to the invention have been shown and described, many modifications thereof may be made by a person skilled in the art without departing from the spirit of the invention, and it is in tended to protect by Letters Patent all forms of the invention falling within the scope of the following claims.

What is claimed is:

1. Pump for pumping blood, kidney fluids, and other relatively delicate fluids, comprising pump housing means having a pumping chamber of substantially circular cross sections therewithin and having a fluid inlet to the center of said pumping chamber and a fluid outlet from the periphery of said pumping chamber, rotator means mounted for rotation within said pumping chamber, electric motor means comprising magnetic pole means associated with one of said rotator means and said'housing means, winding means associated with one of said rotator means and said housing means, and means for supplying electric current to said winding means to drive said rotator means in rotation whereby said rotator means pumps fluid through said pumping chamber from said inlet means to said outlet means; said rotator means comprising vane means extending from said inlet to adjacent said outlet, said vane means having smooth spaced facing surfaces defining said flow passage means therebetween which rotate when said rotator is rotated and frictionally contact fluid introduced to therebetween through said inlet to cause smooth circular movement of the fluid concentric with the rotation of said rotator means and at increased velocity as the fluid moves from said inlet toward said outlet.

2. The combination of claim 1, said magnetic pole means comprising magnetized portions of said vane means.

3. The combination of claim 2, said magnetic pole means being provided in each vane means.

4. The combination of claim 1, said housing means having second chamber means concentric with said pumping chamber, disc means disposed in said second chamber means coupled for rotation with said rotator, seal means around said coupling to prevent fluid flow from said pumping chamber into said second chamber means, said magnetic pole means comprising magnetized portions of said disc means.

5. The combination of claim 1, said magnetic pole means comprising solenoid winding means carried by said rotator; means for supplying electrical current to said solenoid winding means.

6. The combination of claim 5, including plastic layer means covering said solenoid winding means to prevent fluid contact therewith.

7. The combination of claim 1, said winding means being in said housing means and being sealed from said pumping chamber by plastic layer means.

8. The combination of claim 1, said rotator means being coupled to said electric motor means for rotation thereby by magnetic coupling means.

9. The combination of claim 8, at least a portion of said rotator means being suspended for rotation in a magnetic field.

10. Pump for pumping blood, kidney fluids, and other relatively delicate fluids, comprising pump housing means having a pumping chamber of substantially circular cross sections therewithin and having a fluid inlet to the center of said pumping chamber and a fluid outlet from the periphery of said pumping chamber, rotator means mounted for rotation within said pumping chamber, electric motor means comprising magnetic pole means associated with one of said rotator means and said housing means, and means for supplying electrical current to said winding means to drive said rotator means in rotation whereby said rotator means pumps fluid through said pumping chamber from said inlet means to said outlet means; said housing means having second chamber means concentric with said pumping chamber, disc means disposed in said second chamber means coupled for rotation with said rotator, seal means around said coupling to prevent fluid flow from said pumping chamber into said second chamber means, said magnetic pole means comprising magnetized portions of said disc means.

Claims

1. Pump for pumping blood, kidney fluids, and other relatively delicate fluids, comprising pump housing means having a pumping chamber of substantially circular cross sections therewithin and having a fluid inlet to the center of said pumping chamber and a fluid outlet from the periphery of said pumping chamber, rotator means mounted for rotation within said pumping chamber, electric motor means comprising magnetic pole means associated with one of said rotator means and said housing means, winding means associated with one of said rotator means and said housing means, and means for supplying electric current to said winding means to drive said rotator means in rotation whereby said rotator means pumps fluid through said pumping chamber from said inlet means to said outlet means; said rotator means comprising vane means extending from said inlet to adjacent said outlet, said vane means having smooth spaced facing surfaces defining said flow passage means therebetween which rotate when said rotator is rotated and frictionally contact fluid introduced to therebetween through said inlet to cause smooth circular movement of the fluid concentric with the rotation of said rotator means and at increased velocity as the fluid moves from said inlet toward said outlet.