United States Patent [19]
`Raible
`
`[56]
`
`[54] BLOOD PUMP
`[75] Inventor: Donald A. Raible, Santa Ana, Calif.
`[73] Assignee: Baxter International Inc., Deerfield,
`Ill.
`[21] Appl. No.: 83,405
`[22] Filed:
`Jun. 28, 1993
`[51] Int. Cl* ................................................ F04D 1/08
`[52] U.S. Cl. ...................................... 415/74; 415/143;
`415/230; 415/900; 416/177
`[58] Field of Search ....................... 415/71, 72, 73, 74,
`415/143, 230, 900; 416/176, 177
`References Cited
`U.S. PATENT DOCUMENTS
`Re. 28,742 3/1976 Rafferty et al. .
`307,275 10/1984 Edmundson .
`1,226,278 5/1917 Teves .
`2,984,189 5/1961 Jekat ..................................... 415/74
`3,087,435 4/1963 Boucher ................................ 415/72
`3,381,801 5/1968 Rastoin .
`3,647,324 3/1972 Rafferty et al. .
`3,864,055 2/1975 Kletschka et al. .
`3,918,831 11/1975 Grennan .............................. 415/143
`3,957,389 5/1976 Rafferty et al. .
`3,970,408 7/1976 Rafferty et al. .
`4,037,984 7/1976 Rafferty et al. .
`4,449,895 5/1984 Kurahayashi .
`4,456,437 6/1984 Kurahayashi .
`4,625,712 12/1986 Wampler .
`4,846,152 7/1989 Wampler et al. .
`5,040,944 8/1991 Cook .
`
`
`
`|US005368438A
`[11] Patent Number:
`[45] Date of Patent:
`
`5,368,438
`Nov. 29, 1994
`
`5,139,391 8/1992 Carrouset .............................. 415/74
`FOREIGN PATENT DOCUMENTS
`317687 5/1989 European Pat. Off. ............ 415/143
`364293 4/1990 European Pat. Off. .
`378251 7/1990 European Pat. Off. .
`1118405 6/1956 France ................................ 415/230
`1375287 2/1972 United Kingdom .
`1368095 5/1972 United Kingdom .
`1390741 3/1973 United Kingdom .
`2239675 7/1991 United Kingdom .
`WO82/03176 9/1982 WIPO .
`WO85/01432 4/1985 WIPO .
`WO89/04645 6/1989 WIPO .
`WO90/01347 2/1990 WIPO .
`Primary Examiner—Edward K. Look
`Assistant Examiner—James A. Larson
`Attorney, Agent, or Firm—Poms Smith Lande & Rose
`[57]
`ABSTRACT
`A dynamic blood pump includes a rotating core mem
`ber and rotating ring portion effective to pre-spin blood
`before the blood enteres helical pumping channels of
`the pump. The blood is pumped and further rotated as it
`moves axially along the helical channels toward a cen
`trifugal section of the pump. At the centrifugal pumping
`section circumferential velocity differentials are also
`controlled to diminish damage to the blood. Outwardly
`of the centrifugal pumping section, a forced-vortex
`pumping section communicates the pumped blood to an
`exit port.
`
`32 Claims, 3 Drawing Sheets
`
`Petitioners' Exhibit 1010, pg. 1
`
`

`

`U.S. Patent
`
`Nov. 29, 1994
`
`Sheet 1 of 3
`
`5,368,438
`
`F/G |
`
`72a.
`
`3
`
`/4.
`
`*
`
`N 2 2’
`s 2O
`Sl-loo
`/2
`
`i
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`SCS
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`Nil
`N UAE >
`
`
`
`I6 108 40
`42
`44.
`
`36
`
`50
`
`48
`
`68c.
`
`Petitioners' Exhibit 1010, pg. 2
`
`

`

`U.S. Patent
`
`Nov. 29, 1994
`
`Sheet 2 of 3
`
`5,368,438
`
`I/O 108
`
`is a jff
`
`NTT TIS
`IETFI
`
`
`
`
`
`
`
`
`
`
`
`Z22
`
`Ø
`
`
`
`Z
`
`Petitioners' Exhibit 1010, pg. 3
`
`

`

`U.S. Patent
`US. Patent
`
`Nov. 29, 1994
`Nov. 29, 1994
`
`Sheet 3 of 3
`Sheet 3 of 3
`
`5,368,438
`5,368,438
`
`
`
`
`
`Petitioners' Exhibit 1010, pg. 4
`
`Petitioners' Exhibit 1010, pg. 4
`
`

`

`1
`
`BLOOD PUMP
`
`BACKGROUND OF THE INVENTION
`1. Field of the Invention
`The present invention is in the field of liquid pumps.
`More particularly, the present invention is in the field of
`combined axial and centrifugal pumps for pumping
`liquids. Still more particularly, the present invention
`10
`relates to a combined axial and centrifugal pump having
`a centrifugal-flow section and an axial-flow helical in
`ducer section conveying liquid flow to the centrifugal
`section. The present inventive pump has particular util
`ity for pumping blood with minimal damage to the
`formed cells and other constituents of the blood.
`2. Related Technology
`Blood is a complex and delicate fluid. Blood is essen
`tially made up of plasma, which is a pale yellow liquid
`containing microscopic materials including the formed
`20
`constituents of the blood. These formed constituents
`include the red corpuscles (erythrocytes), the white
`corpuscles (leukocytes), and the platelets (thrombo
`cytes). These and other constituents of the blood, as
`well as the suspension of the formed constituents of the
`blood in the plasma, are affected by the manner in
`25
`which blood is physically handled or treated. More
`over, blood is susceptible to damage from a variety of
`physical effects. These include depressurization, shock,
`shear, impact, other forms of physical stress, as well as
`turbulence, and sudden changes in cross sectional area
`30
`of a flow path which causes eddy currents, and which
`may cause small clots to form in the blood.
`Further to the above, it is well recognized that the
`conventional type of positive-displacement roller pump
`which has many uses in the medical field, and which
`35
`employs a length of flexible tubing squeezed in progres
`sive sections between a housing and moving rollers is
`hard on the formed constituents of the blood. These
`formed blood constituents become caught in the mov
`ing nips formed as the rollers move along and squeeze
`the flexible tubing. When so caught and squeezed, the
`formed constituent cells are ruptured and destroyed.
`During many major surgical procedures, such as
`open heart surgery, or cardiovascular-respiratory sup
`port, the need to pump blood arises. This blood pump
`45
`ing necessity arises in connection with the requirement
`to move blood for the patient through heart-lung sys
`tems which filters the blood, removes impurities, oxy
`genates the blood, and controls its temperature to a
`level which reduces the patient's metabolism during the
`50
`surgery. However, as pointed out above, pumping of
`blood is a particularly difficult problem. Such is the case
`because blood is not a simple liquid which can be
`pumped as though it were water or oil, for example. As
`explained above, blood contains many cells, such as red
`55
`and white corpuscles, and other constituents which are
`living tissues of the body. These living blood tissues are
`particularly susceptible to damage and destruction by
`pumping actions which squeeze the blood, as do roller
`type pumps. Also, pumps which subject the blood to
`sudden changes in direction or velocity, which exces
`sively stir the blood, which subject the blood to high
`relative velocities, or which submit the blood to exces
`sive levels of shear, all impose damage on the blood, and
`impose a trauma on a living tissue of the patient under
`65
`going the surgery or medical procedure.
`Many attempts have been made to provide dynamic
`pumps which avoid the deficiencies of the conventional
`
`15
`
`5,368,438
`2
`roller pump and other conventional pumps. One of
`these conventional blood pumps is known in accord
`with U.S. Pat. No. Re. 28,742, reissued 23 March 1976,
`to E. H. Rafferty, et al. The Rafferty reissue patent is
`believed to teach a dynamic blood pump based on the
`forced vortex principle. That is, the pump is based on
`the principle that a spinning chamber forms therein a
`spinning volume of liquid which is pressurized at its
`outer periphery and flows radially outwardly. The
`Rafferty pump defines one or a successive plurality of
`such spinning chambers, the walls of which may be
`smooth with the exception of strut members or other
`such structural features arranged to connect the walls
`together for rotation in unison, or which may include
`radially extending and perhaps forwardly or back
`wardly inclined or swept vanes. In this context, the
`terms forwardly or backwardly inclined or swept vanes
`refer to the circumferential direction in which the vanes
`extend with respect to the normal direction of rotation
`of such a pump rotor. When so equipped with vanes
`extending into the pumping chambers from the rotating
`wall surfaces, the pump configurations of Rafferty are
`more akin to centrifugal pumps than to strict forced
`vortex pumps, the latter which rely on viscous coupling
`between the rotating walls of the pump and the liquid to
`effect spinning and pressurization of the latter.
`As may easily be appreciated, the struts and other
`structural features of the pumps of Rafferty, and partic
`ularly the vanes of these pumps which are of centrifugal
`configuration may impose severe damage on formed
`blood cells. That is, the struts are spaced outwardly
`from the axis of rotation and sweep through the blood
`with a high relative circumferential velocity. Similarly,
`the vanes of the centrifugal versions of Rafferty's
`pumps have edges which may result in abrupt changes
`in cross sectional area of the blood flow channels, in
`turbulence and in shock to the formed constituents of
`the blood.
`Another series of dynamic pumps which are based on
`the forced vortex principle and viscous coupling of the
`blood with the pumping rotors are seen in U.S. Pat.
`Nos. 3,864,055; 3,647,324; 3,970,408; 3,957,389; and
`4,037,984. Considering particularly the first-listed one
`of these patents, it is seen that the pumping elements are
`based on forced vortex principles with the pumping
`chambers being of disk-like, semi-spherical, conical, or
`trumpet-shaped configurations. The pumping chambers
`include a pair of axially spaced apart rotating end wall
`members, and may include intermediate wall members
`which are matched in shape to the end wall members.
`Experience has shown that with blood pumps made
`according to the teachings listed immediately above,
`the pumped blood experiences a higher than preferred
`level of damage. Also, some of these pump configura
`tions are rather complex and expensive to manufacture.
`In the present medical environment with concerns
`about Hepatitis and AIDS mitigating toward a minimi
`zation of contact with a patient’s blood, and the disposal
`of blood wetted equipment, the discarding of such
`pumping devices after a single use constitutes a signifi
`cant expense.
`Still additional conventional dynamic blood pumps
`are seen in U.S. Pat. No. 4,625,712, issued 2 December
`1986; and U.S. Pat. No. 4,846,152, issued 11 July 1989,
`each having R. K. Wampler as a sole or coinventor. The
`blood pumps of the Wampler patents are small, high
`speed, axial-flow designs of single or multiple stages,
`
`Petitioners' Exhibit 1010, pg. 5
`
`

`

`5,368,438
`4
`3
`tween, each of said helical auger flutes merging with a
`and the single stage design includes a slight increase in
`respective one of said vane portions, and each of said
`inner diameter of the flow path so that some centrifugal
`helical pumping channels communicating with a respec
`pumping effect is asserted.
`The Wampler pumps have been found by experience
`tive one of said chamber sectors.
`An advantage of the present inventive pump is that it
`to impose severe damage on the formed constituents of
`avoids sudden changes in cross sectional area of the
`blood. It is believed that the high rotational speed
`developed fluid flow area through the pump. Conse
`which are required for the Wampler pumps to achieve
`quently, sudden changes in fluid flow velocity, turbu
`significant volumes of pumped blood against ordinarily
`lence, and impacts to the fluid, are also avoided. Also,
`head pressures encountered in the use environments of
`the present inventive pump does not require the high
`such pumps is a significant factor in the great damage
`10
`these pumps impose on the pumped blood.
`rotational speeds of some conventional blood pumps in
`order to pump significant quantities of blood against the
`Finally, another conventional blood pump of novel
`head pressures commonly encountered in such uses of
`design is shown in U.S. Pat. No. 5,040,944, issued 20
`the pump. As a result, the present inventive blood pump
`August 1991, to E. P. Cook. The Cook teaching in
`does not whip the blood like some of the conventional
`cludes a pump with an elongate central ribbon-like
`15
`blood pumps.
`member which is helical and stationary. Around this
`As will be further elaborated hereinafter, actual com
`central member rotates an elongate helical rod-like
`parative tests of several conventional blood pumps, and
`member which has a direction of helix opposite to the
`of blood pumps made according to the teaching of the
`central member and which also rotates in this direction.
`present invention, have shown significant advantage for
`While the blood pump according to the Cook patent
`20
`the present pump. That is, the rotational speeds required
`is believed to offer advantages in pumping volume and
`for the present pump are significantly lower. The dam
`developed head pressure in comparison to other con
`age imposed on the pumped blood per unit of time at a
`ventional blood pumps, the rotational speed required of
`given pumping volume and head pressure, or per unit of
`this pump is still much higher than desired. Conse
`blood pumped, is significantly lower for the present
`quently, the Cook pump also imposes somewhat more
`25
`damage on the pumped blood than that which is consid
`inventive blood pump than for the best of the conven
`ered minimal and acceptable.
`tional blood pumps discussed above. When it is remem
`bered that the formed constituents of blood are living
`SUMMARY OF THE INVENTION
`tissues of the patient, and that damage and destruction
`In view of the above, a primary object for the present
`of these tissues results in necrotic factors which must be
`eliminated from the patient’s system by the liver and
`invention is to provide a blood pump which results in
`significantly reduced damage to pumped blood.
`kidneys for the most part, the burden on the patient's
`Yet another object for the present invention is to
`system from this cell damage must be minimized. In
`addition to slowing the patient's recovery, the damaged
`provide such a blood pump which is economical to
`blood cells must eventually be replaced by the patient’s
`manufacture.
`system, which is another factor in patient recovery.
`Another object for the present invention is to provide
`These recovery-slowing burdens and trauma to the
`such a blood pump which avoids bluff or sharp-edged
`patient can be minimized by the use of the present in
`moving through the blood at excessive relative veloci
`ventive blood pump.
`ties.
`These and additional objects and advantages of the
`Additional objects for the present invention are to
`present inventive pump will be apparent from a reading
`provide a blood pump which is dependable, reliable,
`of the following description of a particularly preferred
`durable, and fully effective to accomplish its intended
`purposes of pumping blood with significant head pres
`exemplary embodiment of the present invention, taken
`in conjunction with the following drawing Figures, in
`sures and volume flow rates without the level of dam
`age to the blood which conventional blood pumps
`which:
`45
`would cause.
`DESCRIPTION OF THE DRAWING FIGURES
`Accordingly, the present invention provides a liquid
`FIG. 1 provides a fragmentary elevation view, par
`pump with a housing defining an inlet, an outlet, and a
`tially in cross section, and somewhat schematically
`flow path extending between the inlet and outlet for
`presented, of a pump embodying the present invention;
`communicating a flow of liquid therebetween; a rotor
`member journaled in the flow path for impelling said
`FIG. 2 is a fragmentary cross sectional view taken
`along line 2–2 of FIG. 1, and with parts of the struc
`liquid flow in response to rotation of said rotor member;
`the rotor member including a circumferentially continu
`ture omitted to better depict salient features of the in
`ous ring portion defining an inlet end for said rotor
`vention;
`FIG. 3 is a fragmentary cross sectional view taken at
`member and defining an inlet recess receiving therein
`55
`said liquid flow from said inlet; a helical auger pumping
`line 3—3 of FIG. 1;
`section including plural helical flutes extending from
`FIG. 4 is a cross sectional view taken at line 4–4 of
`said ring portion and cooperatively defining a like num
`FIG. 1;
`ber of helical pumping channels open radially out
`FIG. 5 is a cross sectional view taken at line 5–5 of
`wardly toward a circumferential wall portion of said
`FIG. 1;
`housing and extending axially and circumferentially
`FIG. 6 presents an isolated perspective view of a
`component part of the inventive pump depicted in FIG.
`toward said outlet; said helical channels opening radi
`ally, axially, and circumferentially from said inlet re
`1;
`cess; and a centrifugal pumping section including plural
`FIG. 7 is an enlarged fragmentary cross sectional
`vane portions like in number to said helical flutes and
`view taken at line 7–7 of FIG. 1; and
`65
`each extending radially outwardly into a circumferen
`FIG. 8 is a fragmentary elevation view partially in
`tial chamber of said flow path to cooperatively define
`cross section like FIG. 1, but showing an alternative
`circumferentially extending chamber sectors therebe
`embodiment of the present inventive pump.
`
`30
`
`35
`
`50
`
`Petitioners' Exhibit 1010, pg. 6
`
`

`

`5
`DESCRIPTION OF THE PREFERRED
`EXEMPLARY EMBODIMENTS
`Viewing FIGS. 1–6 in conjunction, it is seen that a
`pump 10 includes a housing 12. The housing 12 includes
`an inlet port, generally referenced with the numeral 14,
`plural outlet ports, each referenced with the numeral
`16, and a flow path 18 communicating the inlet port 14
`with the outlet ports 16. More particularly, the housing
`12 includes a wall portion 20 which is circumferentially
`and axially extending to define a cylindrical bore 22.
`The cylindrical bore 22 at its upper end defines inlet
`port 14, and communicated downwardly to a larger
`diameter bore portion 24. Cooperatively, the bore por
`tions 22 and 24 define a somewhat tapered shallow
`15
`conical shoulder 26 on the housing 12. A circumferen
`tial wall portion 28 of the housing 12 cooperates with
`the shoulder 26 and with a planar back wall portion 30
`to define a circumferential chamber 32 in the flow path
`18. The wall portion 28 defines plural outlet ports 16
`20
`opening circumferentially outwardly from the chamber
`32.
`Below the back wall 30, the housing 12 includes a
`boss 34 which defines therein a stepped bore 36. In this
`stepped bore 36 at an upper larger diameter portion 38
`25
`thereof are received a sealing member 40 and a next
`adjacent upper bearing member 42. The bearing mem
`ber 42 rests upon an upwardly disposed shoulder 44
`formed on the bore 36 by cooperation of the portion 38
`thereof with a smaller diameter bore portion 46. This
`30
`smaller diameter bore portion 46 also cooperates with a
`lower larger diameter portion 48 of the bore 36 to define
`a downwardly disposed shoulder 50. In the bore portion
`48, a second bearing member 52 is disposed in engage
`ment with the shoulder 50.
`35
`As is seen in FIGS. 1 and 6, a rotor member, gener
`ally referenced with the numeral 54 is rotatably jour
`maled in the flow path 18. The rotor member 54 includes
`an elongate shaft portion 56 having an upper seal runner
`58 disposed in the sealing member 40, and a smaller
`diameter stem portion 60 rotationally supported by the
`bearing members 42 and 52. The seal runner portion 58
`bears on the upper bearing member 42. Below the bear
`ing 52, the stem portion 60 of shaft 56 includes a circum
`ferential groove 62 in which is received a retaining ring
`45
`64. The retaining ring 64 bears on bearing 52 to capture
`the sealing member 40, bearings 42 and 52, and shaft 56
`in the boss 34. Consequently, the rotor member 54 is
`rotatably journaled and axially constrained in the flow
`path 18. In order to rotationally drive the rotor member
`50
`54, a lower drive portion 66 is hexagonal in cross sec
`tion to drivingly engage with a driving motor 68, which
`is schematically depicted. Rotation of the rotor member
`54, when viewed from the stem end 66 is clockwise, as
`is indicated by arrow 68a.
`Viewing FIGS. 1–6 in conjunction with one another,
`it is seen that the rotor member 54 includes an elongate
`central core member 70, which includes a conical por
`tion 72 having a tip 72a confronting the inlet port 14,
`and leading to an elongate cylindrical portion 74. Cir
`cumscribing the core member 70 at the conical portion
`72 thereof is a circumferentially continuous ring portion
`76. This ring portion 76 defines an axial entrance end 78
`for the rotor member 54, and also defines an opening
`into a conical and annular entrance recess 80. The coni
`65
`cal entrance recess 80 includes conical surface portions
`82, which are best seen viewing FIGS. 2, 3, and 6. It
`will be noted that in FIG. 2, the wall portion 20 and
`
`5,368,438
`6
`shoulder 26 are omitted to provide a better view of the
`rotor member 54 in the chamber 32. The inner diameter
`84 of the conical entrance recess 80 is slightly larger in
`diameter than the cylindrical portion 74 of core member
`70, and is about coextensive with the upper end of this
`conical core portion, to define a radial clearance 86. As
`is seen in FIGS. 1, 3, and 6, the conical portion 72 of the
`core member 70 extends out of the recess 80 toward the
`inlet port 14 so that upon liquid flow approaching the
`rotor member 54, the cross sectional flow area of flow
`path is first gradually decreased by the conical portion
`72 of the core member 70, and then is additionally grad
`ually reduced as the liquid flow enters into the conical
`entrance recess 80.
`Extending axially and circumferentially from the ring
`portion 76, the rotor member 54 includes three helical
`flute portions 88. As is best seen in FIGS. 1 and 6, the
`ring portion 76 includes transition sections 90 connect
`ing the circumferentially extending body of the ring
`member 76 with the axially angulated helical flutes 88,
`and the flutes 88 are equally spaced apart circumferen
`tially. Each flute portion 88 includes a radially extend
`ing pressure surface 92 disposed toward the chamber
`32, and an axially opposite radially extending suction
`surface 94 which is disposed toward the inlet 14. Cir
`cumferentially successive ones of the flutes 88 cooper
`ate with one another at their surfaces 92 and 94 to define
`a like plurality of radially extending helical channels 96,
`which open radially outwardly toward the housing wall
`portion 20. An outer circumferential and helical surface
`98 is spaced from the wall portion 20 to define a radial
`gap 100. Preferably, the gap 100 is in the range from
`about 0.025 to about 0.040 inches (about 0.6 to about 1.3
`mm).
`Viewing FIGS. 2 and 6, it is seen that each of the
`channels 96 opens radially outwardly, axially, and cir
`cumferentially from the entrance recess 80. Conse
`quently, when viewed in axial view as is seen in FIG. 2,
`the channels 96 each define what appears to be a tear
`drop shaped entrance opening 102 opening outwardly
`from the entrance recess 80 into the helical channels 96.
`Still considering the axial view of FIG. 2, it is seen that
`what appears as a floor of these entrance openings 102
`is the suction surface 94 of the next preceding flute in
`the direction of rotation. Also, a circumferentially ex
`tending and helical leading edge 104 for the pressure
`surface 92 of the respective flute 88 is spaced axially
`toward the viewer of FIG. 2 with respect to the viewed
`portion of surface 94.
`FIGS. 1 and 6 illustrate that the flutes 88 each pro
`ceed through slightly more than one complete turn
`around the core 70 and then define a termination end
`106 on an axially disposed surface 108 on a respective
`one of plural centrifugal vanes 110. That is, the number
`of vanes 110 is equal to the number of flutes 88. Viewing
`FIGS. 2, 4, and 5, it is seen that the vanes 110 are gener
`ally radially extending, but are offset slightly in the
`circumferential direction of rotation to define a larger
`radially and axially extending pusher surface 112, and a
`smaller follower surface 114. In other words, viewing
`FIG. 5 more particularly, it is seen that the vanes 110
`are of generally constant width, extend generally radi
`ally, and are circumferentially offset in the direction of
`rotation with respect to the rotational axis of the rotor
`member 54 which is defined at the stem 60. As a result,
`the pusher surfaces 112 would be tangent to a larger
`circle about the rotational axis at stem 60 than would
`the follower surfaces 114. This result of the circumfer
`
`10
`
`55
`
`Petitioners' Exhibit 1010, pg. 7
`
`

`

`10
`
`15
`
`5
`
`25
`
`5,368,438
`8
`7
`nels 96. Consequently, the spinning liquid in entrance
`ential offset of the vanes 110 can easily be seen by refer
`recess 80 has a tendency to move by its own centrifugal
`ence to the dash circle 124 of FIG. 5 because the pusher
`surfaces 112 are outside of this circle, and would not
`force into the helical channels 96.
`intersect with it if projected inwardly. In contrast, an
`Once in the helical channels 96, the liquid is subjected
`to a greater level of viscous coupling with spinning
`inward projection of the follower surfaces 114 would
`rotor member 54, so that the liquid has a tendency to
`intersect with the dash circle 124. Considering FIGS. 1
`and 6 again, it is to be noted that each of the channels 96
`spin more and more with the rotor member as it moves
`opens smoothly into a respective circumferentially ex
`along channels 96. However, the channels 96 open radi
`ally outwardly toward and are bounded generally by
`tending sector of the chamber 32 between the vanes
`the outer wall 20. Consequently, the viscous drag pro
`110, which chamber sectors are referenced with the
`vided by the outer wall 20 keeps the liquid from merely
`numeral 116.
`Viewing FIGS. 1, 6, and 7, it is seen that the vanes
`spinning with the rotor 54, and causes the liquid to
`advance along the channels 96. Importantly, the outer
`110 have rounded surfaces, and define an outer end 118
`which is spaced radially from the circumferential wall
`wall 20 is spaced from the outer circumferential surface
`28. Additionally, these vanes taper radially outwardly
`98 to define the radial gap 100. This gap is sized to be
`sufficiently small that back flow leakage is not excessive
`as they extend into the circumferential chamber 32.
`and does not result in excessive churning of the pumped
`FIGS. 1 and 7 depict that the vanes 110 are also taper
`liquid (recognizing that pumping inefficiency appears as
`ing axially toward the inlet 14 on their back surfaces
`work dissipated in the pumped liquid which does not
`120. That is, the vanes 110 cooperate with the generally
`appear as pressure or flow energy, and resulting in dam
`planar back wall 30 of the chamber 32 to define an
`20
`axially extending and radially outwardly increasing gap
`age to formed blood constituents). On the other hand,
`the gap 100 is chosen to be sufficiently large that formed
`122. It will be noted that between the vanes 110, the gap
`blood constituents which do pass through this gap with
`122 virtually does not exist because the chamber sectors
`the back flow liquid are not subjected to excessive lev
`116 extend radially inwardly close to the seal runner 58.
`els of shear. Recalling the explanation above of how
`However, viewing FIG. 5, it is seen that around the seal
`conventional pumps damage and destroy the formed
`runner 58 there is a circle denoted with dashed line 124,
`within which the gap 122 is circumferentially complete.
`constituents of blood, it is easily appreciated that the
`size of gap 100 is best determined experimentally for
`FIG. 7 shows that at the seal runner 58, the sealing
`each size and operating speed of pump 10. However,
`member 40 includes a resilient polymeric cup seal 126,
`having a radially outer lip 128 which sealingly engages
`the liquid in the channels 96 does accelerate circumfer
`30
`the housing 12 at bore portion 24. This cup seal 126 also
`entially as it moves along the channels 96 so that its
`circumferential velocity approaches that of the adjacent
`includes a radially inner lip 130 which forms a dynamic
`seal with the rotational seal runner portion 58 of shaft
`surfaces of the rotor member 54, as will be further ex
`plained.
`56. Between the lips 128 and 130, the cup seal 126 de
`fines a circumferentially extending axial groove 132.
`As the channels 96 open into the chamber sectors 116,
`35
`Disposed in the groove 132 is a low-friction blood com
`the respective pressure surface 92 leads to and blends
`patible polymeric filler member 134, which defines a
`into the pusher surface 112 of the chamber sector 116.
`planar upper surface 136 disposed toward and in closely
`Similarly, the suction surface of the channel 96 leads to
`spaced relation with the back surface 120 of rotor mem
`and ends on the axial surface 108 of a respective vane
`110 immediately adjacent to the respective follower
`ber 54. Importantly, within the circle 124 (recalling
`FIG. 5), the filler member 134 substantially fills the gap
`surface 114. Consequently, at the transitions from the
`helical auger pumping section which is represented by
`122.
`Having observed the structure of the pump 10, atten
`the helical flutes 88 and the centrifugal pumping section
`tion may now be turned to its operation. With the flow
`which is comprised of vanes 110, the liquid flow is not
`path 18 filled with liquid (the pump 10 not being self
`subjected to any turbulence or pressure shock. Addi
`45
`priming) rotation of the rotor member 54 by drive
`tionally, as noted above, the liquid has been circumfer
`entially accelerating along the channels 96 so that by
`motor 68 as indicated by arrow 68a, impels liquid flow
`along the flow path 18 toward the entrance end 78 of
`the time the liquid is discharged from these channels
`rotor 54. As this liquid flow approaches the rotor mem
`into the chamber 32 its circumferential velocity is
`ber 54 it first encounters the conical end portion 72 of 50
`nearly that of the adjacent surfaces of the rotor 54, and
`no subjecting of the liquid to surfaces moving through it
`core member 70. Shortly thereafter, the liquid flow
`at high relative velocity is experienced.
`encounters the entrance end 78 of ring portion 76 lead
`ing to entrance recess 80, and flows therein. Consider
`In the chamber 32, the liquid is radially and circum
`ing the experience of the liquid to this point, is seen that
`ferentially accelerated by action of the vanes 110. The
`abrupt changes in cross sectional area developed in the
`fact that these vanes have pusher surfaces 112 which are
`55
`flow path 18 by the cooperation of housing 12 and rotor
`enlarged by the circumferential offset of the vanes rela
`member 54 are avoided. Additionally, the ring portion
`tive to the shaft 56 is considered an important feature in
`76 and core 70 with its conical end portion 72 extending
`the interest of minimizing damage to the formed constit
`axially into the approaching liquid flow are spinning.
`uents of blood pumped with the pump 10. Importantly,
`Consequently, a pre-spin is provided to the approaching
`the vanes 110 terminate at radially outer ends 118
`liquid by viscous coupling therewith.
`spaced radially from the circumferential wall 28 so that
`Once this pre-spun liquid is in the entrance recess 80,
`the pump 10 includes an element of forced vortex
`it encounters the circumferentially swept leading edges
`pumping in the chamber 32 outwardly of the vanes 110.
`104 of the entrance openings 102 into the helical chan
`From the chamber 32, the pumped liquid exits via plural
`radially extending outlet ports 16.
`nels 96. These leading edges 104 are rounded so as not
`65
`to impose impacts on the formed constituents of blood
`Recalling also FIG. 7, it will be seen that the filler
`pumped with the pump 10. Further, the leading edges
`member 134 performs two beneficial functions in the
`104 lead radially outwardly and helically to the chan
`use environment of the pump 10. First, this filler mem
`
`Petitioners' Exhibit 1010, pg. 8
`
`

`

`5
`
`5,368,438
`9
`10
`ber 134 fills the circumferential void created in the cup
`of the mechanical drive from motor 68 to rotor 54
`sealing member 126 between the lips 128 and 130. Con
`which is depicted in FIG. 1, this drive can be effected
`sequently, the creation of a substantially stagnant void
`with a magnetic coupling, preferably of the hermetic.
`type. Alternatively, a flex shaft can be used to transfer
`volume in this seal member is avoided. Those ordinarily
`driving power to the rotor 54. The depicted and de
`skilled in the pertinent arts will recognize that such a
`stagnant void volume could cause blood clots to form,
`scribed preferred embodiments of the invention are
`possibly to subsequently be sloughed off and to cause
`exemplary only, and ar