United States Patent [1.]
`
`Reich et al. '
`
`[11]
`[45]
`
`4,135,253
`Jan. 23, 1979
`
`[54] CENTRIFUGAL BLOOD PUMP FOR
`CARDIAC ASSIST
`[75] Inventors: Sanford Reich, St. Louis Park;
`‘
`i
`'
`William H. Gates, Fridley, both of
`Minn.
`[73] Assignee: Medtrouic, Inc., Minneapolis, Minn.
`[21] Appl. No.: 746,008
`[22] Filed:
`Nov. 30, 1976
`[51] Int. Cl.2 ........................ .. A61F 1/24; A61M 1/03
`[52] US. Cl. ...................................... .. 3/1.7; 128/1 D;
`417/420; 415/112; 415/212 R; 415/215;
`415/016.4
`[58] Field ofSearch ....... .. 3/1.7, 1; 128/1 D, DIG. 3;
`417/420; 415mm. 4, 112, 212 R, 215, 206
`References Cited
`U.S. PATENT DOCUMENTS
`
`[56]
`
`3,169,486
`3,608,088
`3,864,055
`
`2/1965 Freed ............................. .. 415/215 X
`9/1971 Dorman et al. .................... .. 3/ 1.7
`2/1975 Kletschka et al. ..... ... ..... .. 415/215 X
`
`OTHER PUBLICATIONS
`“Prolonged Pulsatile and Nonpulsatile LV Bypass with
`a Centrifugal Pump” by G. G. Johnston et al, Transac
`tions American Society for Arti?cial Internal Organs,
`vol. XXII, April 1-3, 1976, pp. 323-331.
`“A Compact Low Hemolysis, Non-Thrombogenic
`System for Non-Thoracotomy Prolonged Left Ventric
`
`ular Bypass” by E. F. Bernstein et al, Transactions
`ASAIO, vol. XX, 1974, PP. 643-654.
`“An Arti?cal Heart That Doesn’t Beat” AMA, Feb. 18,
`1974, vol. 227, No. 7, pp. 735 and 738.
`Primary Examiner-Ronald L. Frinks
`Attorney, Agent, .or-Fimz-Cameron, Kerkam, Sutton,
`Stowell & Stowell
`[57]
`'‘ ABSTRACT
`A centrifugal blood pump and method of pumping
`blood is disclosed to provide assistance for a dysfunc
`tional heart. The pump is provided with a magnetic
`drive system which permits a synchronous magnetic
`coupling with a separate power unit disposed immedi
`ately adjacent the pump housing. The pump has a single
`moving part which includes the combination of an im
`peller connected to a magnetic drive rotor. The impel
`ler is of improved blade and hub design to automatically
`move blood, and‘ minimize formation of blood clots and
`?brous amalgamation in the region of blood flow. Fur
`ther, the impeller blades are con?gured to extend al
`most completely across the bottom surface of the impel
`ler hub to enhance ef?ciency and clot-free operation.
`The magnetic drivesystem ?oats on a ?uid surface of
`saline solution, which hydrodynamically supports and
`lubricates the magnetic drive rotor contained in a com
`partment separate from the impeller and facilitates a
`prolonged period of service-free operation.
`
`17 Claims, 5 Drawing Figures
`
`

`

`U.S. Patent
`
`Jan. 23, 1979
`
`Sheet 1 of 2
`
`4,135,253
`
`FIG.
`
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`
`Page 2 of 7
`
`ABIOMED Ex. 1048
`
`

`

`U.S. Patent
`Jan. 23, 1979
`US. Patent Jan. 23, 1979
`
`Sheet 2 of 2
`Sheet 2 of 2
`
`4,135,253
`4,135,253
`
`FIG.3.
`
`FIG.4.
`
`FIG.4.
`
`[99
`I
`m
`
`96/
`
`Page 3 of 7
`
`ABIOMED Ex. 1048
`
`

`

`1
`
`CENTRIFUGAL BLOOD PUMP FOR CARDIAC
`ASSIST
`
`4,135,253
`2
`It is still another object of this invention to provide a
`centrifugal blood pump which is lubricated with a saline
`solution contained in its impeller rotor chamber.
`It is a further object of this invention to provide a
`centrifugal blood pump wherein there is provided a seal
`for maintaining its rotor chamber free of blood.
`In accorddance with these and other objects, there is
`provided a new and improved centrifugal blood pump
`which includes a housing divided by a baf?e plate to
`provide an impeller chamber and a rotor chamber. An
`improved impeller, which substantially eliminates blood
`clot formation between the impeller and the baf?e plate
`is disposed within the impeller chamber, and includes a
`hub having a shank receiving end and a plurality of
`blades which extend a sufficient distance across the
`shank receiving end to move blood rapidly from a space
`between the impeller and the baf?e plate, thereby mini
`mizing blood clot formation, and cleaning away any
`clots from between the impeller and the baf?e plate.
`The rotor chamber contains a magnetic rotor which
`?oats on a solution of saline for lubricating purposes.
`The baf?e plate separating the two chambers includes a
`rotor shank seal which retains a saline solution in the
`rotor chamber. In addition, the saline solution is circu
`lated periodically in the rotor chamber to flush the
`chamber and to replenish the saline with fresh solution.
`The saline solution also serves to keep blood from enter
`ing the rotor chamber from between the impeller and
`the rotor shank seal.
`
`20
`
`25
`
`BACKGROND OF THE INVENTION
`The present invention is directed to a centrifugal,
`magnetically driven blood pump to be used as a cardiac
`assist device, and the method of using the same. Al
`though the primary purpose of the pump of the present
`invention is to provide assistance to or a replacement
`for a dysfunctional heart in a living body, it is presently
`capable to be used as a blood pump for open-heart sur
`gery where bypass of the heart is needed or for assist
`ance of the damaged left ventricle. In an illustrative
`embodiment of this invention, the blood pump may be
`implanted with no wire or tubes through the skin of a
`human, whereby a magnetic drive system is utilized
`which is operated from a magnetic or electromagnetic
`energy source outside of the body.
`Modern medical practices have advanced in the field
`of cardiac assist devices from the early days of pace
`makers to the use of cardiac assist pumps which now
`perform all or part of the work normally done by a
`failing heart. Many experimental cardiac assist pumps,
`in the past, have been totally implanted actuators with
`their own power sources or implanted devices with
`wires or tubes passing through the user’s skin to an
`outside power source. There is a prior art heart pump
`which requires no implanted power source or wires or
`tubes connected to the outside power source. This
`pump and power source includes an impeller connected
`to a rotor for centrifugally pumping blood to the heart.
`A high-energy bar magnet is set in and secured to a
`transverse slot in the rotor for rotating the impeller
`when acted upon by an outside power source. The rotor
`of the pump is driven by a high-energy drive magnet
`similar to the bar magnet of the pump rotor connected
`to a power supply, such as a portable battery pack. The
`drive manget is intended to be disposed immediately
`adjacent the skin surface of the user in axial alignment
`with the pump rotor. Lubrication of the rotating rotor
`impeller combination is done by circulating blood be
`tween the stationary parts of the pump and the rotating
`rotor-impeller.
`With this implantable blood pump, there is a ten
`dency for blood clots to form in the space formed be
`tween the impeller and an inclined wall of a thrust plate,
`disposed adjacent to the impeller. The impeller has
`blades which radiate from a hub in a manner as to leave
`a relatively large hub surface area adjacent to the thrust
`plate. The blood also lubricates the rotating pump parts
`and therefore ?oods in the space between the hub and
`thrust plate. As a result of this pump construction, the
`?ow of blood between the large hub surface area adja
`cent to the thrust blade tends to be very slow thereby
`55
`enhancing formation of blood clots. As a direct result of
`te clot formations between the impeller and the thrust
`plate, the impeller is forced away from the thrust plate,
`drawing the magnetic rotor up against the ?at, rear face
`of the thrust plate, resulting in seizure of the pump. The
`60
`present invention is an improvement over this blood
`pump and is designed to
`the problem of clot
`formation.
`
`35
`
`40
`
`45
`
`50
`
`SUMMARY OF THE INVENTION
`It is an object of this invention to provide a centriful
`gal blood pump of improved design which substantially
`reduces the possibility of stable clot formation.
`
`65
`
`DESCRIPTION OF THE DRAWINGS
`Other objects and advantages of this invention will
`become apparent from the following detailed descrip
`tion thereof and the accompanying drawings, wherein:
`FIG. 1 is a sectioned view passing through the longi
`tudinal axis of an improved blood pump in accordance
`with teachings of this invention.
`FIG. 2 is a transverse sectioned view along the line
`2-2 of the heart pump in FIG. 1 and in the direction of
`the arrows;
`FIG. 5 is a top plan view of the improved impeller of
`the present invention;
`FIG. 4 is a bottom plan view of the improved impel
`ler of the present invention, as incorporated into the
`blood pump of FIG. 1;
`FIG. 3 is a transverse section along the line 3—-3 of
`the impeller of FIGS. 5 and 4 and in the direction of the
`arrows; and
`FIG. 6 is a schematic representation showing the
`pump of the present invention implanted within the
`human body and coupled through the skin wth an exter
`nal power unit.
`
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENT
`Referring now to the drawings and in particular FIG.
`1, the pump according to the present invention includes
`a cylindrical heart pump housing indicated generally at
`10, having a blood inlet 12 and outlet 14. Within the
`pump housing 10 there is a scroll pump chamber 18
`separated from a rotor housing 20 by a baf?e plate 22. In
`the scroll pump chamber there is a blood circulating
`impeller 24 which forms a significant aspect of this
`invention and will be discussed in detail later. The rotor
`housing 20 contains a rotor chamber 25 and a magnetic
`rotor 26 and a shank 28 for connection to the impeller
`24. Lubrication of the rotor 26 is done by pumping a
`saline solution through an inlet port 30 through the
`
`

`

`20
`
`25
`
`cobalt. '
`
`_
`
`4,135,253
`4
`3
`rotor housing 20 and out through outlet port 32. The
`‘through rotor chamber 25 function like a ?uid lubricant
`cylindrical pump housing 10, includes a cylindrical
`eliminating any friction between the moving and non
`scroll pump casing 34 with a transverse circular ?ange
`moving parts. In other words, ?at surfaces 86 and 88 of
`36 extending inwardly from the inside surface of the
`rotor 26 do not» come in'contact with thrust plate 42 or
`pump casing 34 intermediate of the ends of the pump
`spacer element 62 but instead rides on a ?uid cushion of
`housing 10. The inlet opening v12 is . coaxial with the
`saline solution. The saline solution circulating through
`longitudinal axis of the pump housing 10 and communi
`out chamber 25 also comes in contact with seal 72 and
`cates through a slightly restricted ori?ce ‘38 with the
`baf?e plate 22. The pressure of the saline solution
`scroll impeller chamber 18 from which a diffuser tube
`against seal 72 and shank 78 of impeller 24 prevents
`40 is disposed tangentially with respect to the chamber
`blood from seeping from the pump chamber 18 into
`18 and down stream of the inlet opening 12, to provide
`rotor chamber 25. The saline solution in addition to not
`discharge outlet ‘14.
`allowing blood to pass between the seal 72 in shank 78,
`The outside wall of pump casing 34 on the opposite
`may cause a reverse ?ow of saline solution into pump
`side of ?ange 36 is threaded to receive an internally
`. chamber 18, which is harmless. The saline solution exits
`threaded rotor housing 20. Rotor housing 20 generally
`the rotor chamber 25 through outlet 32. The use of a
`is of a cylindrical shape, with a sealed, closed end. A
`saline solution to lubricate the rotor 26 has the advan
`rear thrust plate 42 is disposed between the inside bot
`tage of preventing any blood which may seep into rotor
`tom surface of the rotor housing 20 and rotor 26. The
`chamber 25 from clotting and further it has been found
`baf?e plate 22 is disposed in the opening betwen a rotor
`that the use of saline solutions do not have a detrimental
`chamber 25 formed within the rotor housing 20 and the
`effect on the working parts of the rotor. In an illustra
`scroll chamber 18, with the baf?e plate 22 pressed in
`tive embodiment of this invention, the saline solution
`sealing contact against an inner surface of an annularly
`was pumped through chamber 25 to establish pressure
`shaped insert 44. The insert 44 held in place between the
`of 200 mm of Hg ‘therein, whereby, as tests have indi
`pump casing 34 and the rotor housing 20, extends from
`cated, that a loss of less than 20 milliliters of the saline
`an annular groove 46 within the ?ange 36 of the casing
`solution was lost about the seal 72 in 24 hours of contin
`34 to a slot 48 formed between pump casing 34 and the
`uous pump use.
`rotor housing 20. A pair of O-rings 50 and 52, respec
`The pump 10 is constructed of materials which are
`tively, are disposed between an annularly shaped
`compatible with body ?uids with which they come into
`groove 54 with a ?ange portion 56 of the insert 44 and
`contact. For example, the pump casing 34 and rotor
`an abutting portion of the baf?e plate, and a circular
`30
`housing 20 are made of seamless epoxy resin coated
`groove 58 within an extended portion 60 of the insert 44
`with an elastomer, such as silicone polyurethane block
`and an abutting surface of the rotor housing 20 whereby
`copolymer. The other surfaces, with which blood
`the pump chamber 18 is liquid sealed with respect to the
`comes into contact," which includes impeller 24 and
`interior of the rotor housing 20. The rotor 26 is sup
`baf?e’v plate 22, may consist of pyrolytic carbon. The
`ported between the thrust plate 42 and the baf?e plate
`35
`_ rotor 26 and rotor housing 20 may be made of stainless
`22, using a space element 62 to limit the axial movement
`steel. The magnet 64 is formed of high-energy samarium
`of the rotor 26.
`Rotor 26 includes a high-energy magnet 64 set in and
`secured in a transverse slot 66 in the rear face of the
`rotor 26 to form a ?ush ?t and'uninterrupted surface.
`The rotor 26 has ashank 28 which connects‘ to a double
`ended threaded connector'68, which also connects to
`the impeller 24 as will be explained. There an axially
`disposed opening 70 in spacer element 62 to align the
`shank 28 with a seal 72 in baf?e plate 22.,
`45
`The impeller 24 includes a generally conical hub 74
`supporting a plurality of radially-extending blades 76.
`The impeller blades 76 are generally in the form of
`trapezoids secured at one end to hub 74. Hub 74 has a
`threaded shank 78 which is received on the connector
`68. The threads of the shank 78 are opposite in direction
`from the direction of rotation of the rotor 26 such that
`accidental detachment of the impeller 24 from the rotor
`26 by unscrewing the shank 78 is avoided. The shank 78
`extends through an axially disposed opening 80 in the
`seal element 72. The seal element 72 is mounted in an
`axially disposed opening 82 of baf?e plate 22 such that
`a lip 84 contacts the shank 78 to prevent blood from
`seeping between the shank 78 and seal element 72. The
`seal is positioned in the baf?e plate 22 such that lip v84 is
`60
`?ush with the blood chamber side of baf?e plate 22 to
`prevent any build-up of blood around the seal; this also
`the area of blood-seal contact and eliminates
`a region of potential stasis.
`’
`Lubrication of the parallel ?at surfaces 86 and 88 of
`65
`the rotor 26 is accomplished by introducing a saline
`solution into the rotor chamber 25 through inlet port 30,
`shown in FIGS. 1 and 2. The saline solution circulating
`
`Referring to FIGS. 3,4 and '5, there is shown a cross
`section view of the improved impeller 24 of this inven
`tion. The impeller hub 74 is generally a disc-shaped
`structure with conical end 90 and a shank end 92. The
`shank 78 extends transversely from the shank receiving
`end 92 of the hub 74. The radiating blades 76, best
`shown in ‘FIGS. 3 and 4, are secured to the hub 74 such
`that the shank 78’extending from the hub 74 and where
`the blades '76 radiate from'the hub 74, intersect. It is
`important that the baldes 76 extend across the shank
`receiving end 92 of the hub 74 and contact or come
`fairly close ‘to contacting the shank 78 to rapidly move
`the blood from between the impeller hub 74 and baf?e
`plate 22, thereby minimizing the formation of blood
`clots and stable ?brous deposits.
`The impeller blades 76 as shown in FIG. 3' do not
`radiate from the center of the hub 74 but instead are
`off-set to the side of shank 78 and are disposed substan
`tially tangential to the hub 74. In addition the blades 76
`have a slight curvature such that the blood is contained
`between the blades 76 and is more ef?ciently pumped to
`outlet 14. Because of the blades 76 being off-set from the
`center of the hub 74 and the slight curvature of the
`blades 76, the blood is moved more rapidly; this desired
`action is also aided by the fact that the blades 76 extend
`far enough-across the bottom surface of the hub 74 to
`eliminate any ?at surfaces on the hub thereby minimiz
`ing regions of stasis. If impeller hub 52 had a ?at surface
`between the hub and the baf?e plate 22 there would not
`be sufficient pumping action of the blood and, therefore,
`
`40
`
`55
`
`

`

`" 4,135,253
`
`5
`a point where iblOOCl'
`the flow of blood would slow to
`
`clots could form. Referring to FIG. 6, there is- shown schematicallythe - .. .3 .~
`
`
`
`
`
`manner in which the blood pump 10, in a further. em
`bodiment of this invention, may be implanted, forrexam- '
`ple in the chest cavity of a patient. Blood in?ow to the
`pump is through a cannula 94 into the ventricle cavity
`to the inlet 12. Out?ow is from the diffuser tube 40
`through a Dacron graft tube 95 to the descending thora
`ciac aorta. In this manner, the pump 10 receives and
`discharges blood which otherwise would pass through
`the heart, so as to reduce the flow of blood through the
`heart and reduce the pumping load otherwise put on the
`heart. Presently, it is contemplated that an implanted
`blood pump 10, as shown in FIG. 6, would not include
`the feature of lubricating the rotor by a saline solution
`directed through the rotor housing 20, as shown in FIG.
`
`1.
`
`_
`
`~
`
`‘
`
`30
`
`35
`
`45
`
`6
`.manipulating the pump impeller rotational velocity
`‘ only.‘- The pressure curve is ?at to within 10 % over the
`'4 range of blood flow needed by the body. Typically, the
`‘ impeller. of the pump is rotated at about 4000 It runs at
`@‘a'cons‘tant speed which may be changed, depending
`upon needs of the situation. The implanted pump has
`' but a single moving con?gured assembly, namely the
`impeller 24 connected to rotor 26. The bearing surfaces
`are lubricated with saline solution. So long as the pump
`is properly constructed from appropriate material to
`prevent chemical attack, the pump has an inde?nite
`lifetime. There is no wear on the rotor due to wall
`contact as a result of the saline lubricant. The external
`drive motor and magnet» can be serviced or quickly
`replaced without surgery.
`Numerous changes may be made in te above
`described apparatus and the different embodiments of
`the invention may be made without departing from the
`spirit thereof; therefore, it is intended that all matter
`contained in the foregoing description and in the ac
`companying drawings shall be interpreted as illustrative
`and not in a limiting sense.
`I
`What is claimed is:
`1. A centrifugal blood pump comprising:
`(a) pump housing means having a ?rst chamber, a
`second chamber and baf?e means disposed there
`between and having an aperture communicating
`between said ?rst and second chamber including an
`inlet and an outlet for receiving and dispensing
`blood into and from said ?rst chamber respec
`tively;
`(b) rotor means rotatively mounted within said sec
`ond chamber and adapted to be rotated by drive
`means coupled thereto;
`(0) an impeller rotatively disposed within said ?rst
`chamber and connected by coupling means to said
`rotor means through said aperture of said baf?e
`plate to be rotated thereby, said impeller including
`a plurality of blades extending from an axis thereof,
`‘whereby blood is pumpled from said inlet to said
`outlet;
`((1) seal means disposed between said coupling means
`and said aperture for isolating a lubricating solution
`disposed within said second chamber from the
`blood pumped through the ?rst chamber; and
`(e) said impeller includes a vhub having a shank end
`connected via a shank to said impeller, and a coni
`cal end, said plurality of blades extending from said
`hub, each of said plurality of blades having an edge
`extending from a point disposed relatively close to
`said baf?e plate and adjacent to said shank along a
`countour corresponding to that of said baf?e plate, 4
`said shank end of said hub con?gured to extend
`from said adjacent pointsand increasingly away
`from said baf?e plate to thereby de?ne a portion of
`each of said plurality of blades disposed between
`said shank end of said hub and said baf?e plate for
`rapidly moving the blood in the vicinity of said
`shank.
`2. A centrifugal blood pump as claimed in claim 1,
`wherein said hub includes an outer circumference and
`each of said plurality of blades extends from said hub
`along a line disposed generally tangential with said
`outer circumference.
`3. A centrifugal blood pump comprising:
`a) a cylindrical pump housing having a scroll pump
`chamber within said housing, a rotor housing con
`nected to said pump housing having a rotor cham
`
`‘As shown in FIG. 6, the pump 10 is implanted with
`the outside transverse surface of the rotor‘housing 20
`20
`underlying the skin surface 37 and the axis of rotation
`substantially normal to the skin surface 37. The rotor 26
`of the pump 10 is driven from a driven magnet power
`pack indicated generally at 41. The drive magnet power
`pack 41 is a high-energy magnet similar to that of the
`25
`pump rotor 26, and is desirably enclosed in a rotor
`housing 96 to minimize air drag. The drive magnet
`power pack 41 is mounted to be rotated by a direct
`current motor 97 connected by connector wires 98 and
`99 to a suitable power source 100, such as a small porta
`ble battery pack which is easily carried by the patient.
`The drive magnet pack 41 is disposed immediately adja
`cent the skin surface 37 of the user in axial alignment
`with the pump rotor 26. Alternately, the pump rotor 26
`may be driven by setting up a rotary electromagnetic
`?eld by means of suitable coils disposed adjacent the
`skin surface in alignment with-the pump.
`In use, blood is slightly ‘accelerated as it passes
`through the throat 38 into the scroll impeller chamber
`18. The blood is pumped centrifugally by action of the
`impeller blades 76 rotated at high speeds. The inverted
`venturi exit from the scroll chamber 18 decelerates the
`blood flow before it returns through the outlet 14.
`In a preferred embodiment, as now contemplated, the
`blood pump 10 is disposed extracorporeally ‘of the pa
`tient and the blood pump 10 is coupled to a pump drive
`unit comprising a motor driven magnet, motor drive
`control electronics, a blood flowmeter and other mea
`suring equipment displays and controls. The pump 10 is
`positioned so that the motor driven magnetic ?eld cou
`ples with the magnetic rotor. The pump drive ‘unit and
`the extracorporeal operation of the pump is further
`described in the paper entitled “Twenty-Four Hour Left
`Ventricular Bypass with a Centrifugal Blood Pump”, E. F.
`Bernstein et al, ANNALS of SURGERY,’ Vol. l81, No.
`4. April, 1975, by I. B. Lippincott Company.
`Where pulsatile blood ?ow is considered to be desir
`‘able or necessary, the pump output pressure can be
`made to simulate the pressure pulsation of the natural
`heart by changing speeds so as to cause the output pres
`sure to change. The rotational velocity of the impeller
`24 determines the output pressure.
`,
`~
`The pump is optimized in dimension. for the blood
`pressure head and flow rates needed, for example about
`100mm Hg pressure and 6 liters/min. ?ow. By way of 65
`reference, the outside diameter of the pump housing is
`approximately 2 inches. The characteristics of the pump
`are such that the blood pressure can be established by
`
`50
`
`55
`
`60
`
`

`

`20
`
`4,135,253
`7
`magnet and is driven by a magnetic coupling by motor
`ber and a baf?e plate separating said pump housing
`from said rotor housing, an axially disposed aper
`means disposed exterior to said pump.
`ture in said baf?e plate, an impeller having a ?rst
`11. A centrifugal blood pump as claimed in claim 10
`shank and disposed in said pump housing;
`'
`wherein said rotor is lubricated by a saline solution,
`b) a rotor having a second shank and disposed in said 5
`whereby said rotor is maintained in a friction reduced
`rotor housing, said impeller being connected to
`' relationship to said rotor housing.
`said rotor by passing said ?rst shank through said
`12. A centrifugal blood pump as claimed in claim 11
`axially disposed aperture in said baf?e plate and
`wherein said rotor housing includes a thrust plate be
`connected to said second shank;
`tween said rotor housing and said rotor and said rotor is
`c) a seal surrounding 'said ?rst shank and af?xed in
`spaced from said baf?e plate by a spacer element which
`said axially disposed aperture of said baf?e plate to
`includes an axially disposed aperture for receiving
`prevent blood in said pump chamber from seeping
`therethrough said second shank on said rotor.
`into said rotor chamber;
`13. A centrifugal blood pump comprising:
`d) an axially disposed ?rst inlet in said pump housing
`a housing;
`for bringing blood into said pump chamber;
`a scroll pump chamber within said housing;
`e) a transverse ?rst outlet in said pump housing for
`an axial inlet to and tangential outlet from said scroll
`removing blood from said pump chamber;
`pump chamber;
`f) a second inlet in said rotor chamber for bringing a
`pump means within said scroll pump chamber for
`saline solution lubricant into said rotor chamber;
`moving blood therethrough comprising an impeller
`and
`mounted for rotation in said chamber;
`g) a second outlet in said rotor chamber for removing
`magnetic drive means for driving said pumping
`the saline solution lubricant from said rotor cham
`means;
`ber.
`a rotor chamber within said housing for enclosing
`4. A centrfugal blood pump as claimed in claim 3,
`said drive means and for receiving a liquid lubri
`wherein said impeller includes a hub having a shank end
`25
`cant; and
`connected to said shank and a conical end, and a plural
`at least the portion of said housing enclosing said
`ity of radiating blades extending from said hub, said
`drive means being electrically non-conductive
`blades being generated from said shank, said hub being
`whereby said drive means may be driven by a me
`maintained at a position out of contact with said baf?e
`chanically unconnected external source of mag
`plate, whereby said blades direct rapidly the blood from
`netic energy, wherein an improvement comprising:
`between said shank end of said hub and baf?e plate.
`a baf?e plate disposed between said scroll pump
`5. A centrifugal blood pump as claimed in claim 4,
`chamber and said rotor chamber and including a
`wherein said impeller blades are positioned on said
`center aperture, and said impeller having an impel
`impeller hub such that said blades are offset of the axial
`ler shank extending through said center aperture in
`center line of said hub, and said impeller hub includes a
`said baf?e plate, said magnetic drive means includ
`radius of curvature in the direction of rotation of said
`ing a rotor and connected to said impeller shank, a
`impeller.
`seal disposed in said aperture of said baf?e plate to
`6. A centrifugal blood pump as claimed in claim 4,
`surround said impeller shank and having the prop
`wherein said conical end of said hub is axially disposed
`erty of substantially blocking the passage of the
`of said cylindrical pump housing and in-line with said 40
`lubricant into said scroll pump chamber, said im
`?rst inlet to de?ect incoming blood to said impeller
`peller including a hub from which said shank ex
`blades.
`tends and a plurality of radiating blade members,
`7. A centrifugal blood pump as claimed in claim 5,
`said hub having a conical end and a shank end, said
`wherein said baf?e plate separating said pump chamber
`blade members being secured to the shank end of
`from said rotor chamber is ?uid sealed to prevent pas
`45
`said hub and said conical end of said hub, said blade
`sage of ?uids between said pump chamber and said
`members extend from said shank of said hub to
`rotor chamber.
`maintain said hub out of contact with said baf?e
`8. A centrifugal blood pump as claimed in cliam 7,
`plate.
`wherein said baf?e plate includes a pump chamber sur
`14. A centrifugal blood pump as claimed in claim 13
`face and a rotor chamber surface, and said seal includes
`wherein said blade members being secured to said hub
`a lip which extends through said baf?e plate to said
`shank end approximate to the point where said shank
`pump chamber surface and is disposed flush with said
`extends transversely from said hub.
`pump chamber surface.
`15. A centrifugal blood pump as claimed in claim 14,
`9. A centrifugal blood pump as claimed in claim 3,
`wherein said blade members are secured offset to said
`wherein there is included means for directing the saline
`hub at an angle to the axial center line of said hub.
`solution into said rotor chamber through said second
`16. A centrifugal blood pump as claimed in claim 15,
`inlet and from said rotor chamber through said second
`wherein said rotor housing includes an inlet port and an
`outlet so that the pressure of that saline solution as
`outlet port for introducing lubricating ?uids to said
`exerted against said seal is greater than the pressure
`exerted upon said seal by the blood in said pump cham
`rotor.
`17. A centrifugal blood pump as claimed in claim 16,
`ber.
`wherein said lubricating ?uid is a saline solution.
`10. A centrifugal blood pump as claimed in claim 4,
`# i t ll
`i
`wherein said rotor in said rotor chamber includes a
`
`60
`
`65
`
`30
`
`35
`
`50
`
`55
`
`