U.S. patent application number 10/239602 was filed with the patent office on 2003-07-03 for rotary pump comprising a hydraulically mounted rotor.
Invention is credited to Raderer, Franz, Schima, Heinrich, Schistek, Roland, Schmallegger, Helmut.
Application Number | 20030124007 10/239602 |
Document ID | / |
Family ID | 3675541 |
Filed Date | 2003-07-03 |
United States Patent
Application |
20030124007 |
Kind Code |
A1 |
Schima, Heinrich ; et
al. |
July 3, 2003 |
Rotary pump comprising a hydraulically mounted rotor
Abstract
The invention relates to a pump for moving blood and other
shear-sensitive with a rotor journaled hydraulically and, if
necessary, magnetically in a housing and where the rotor (1) has
flow-control surfaces (2, 4, 35, 33, 37, 41) for producing
centrifugal flow components (3) and flow components (4) directed
against the housing (30), the centrifugal flow components (3)
serving mainly for producing the externally effective throughput
and the flow components (5) directed against the housing serving
mainly for contact-free journaling and stabilizing of the rotor in
the housing.
Inventors: |
Schima, Heinrich; (Wien,
AT) ; Schmallegger, Helmut; (Wien, AT) ;
Schistek, Roland; (Wals-Siezenheim, AT) ; Raderer,
Franz; (Wien, AT) |
Correspondence
Address: |
THE FIRM OF KARL F ROSS
5676 RIVERDALE AVENUE
PO BOX 900
RIVERDALE (BRONX)
NY
10471-0900
US
|
Family ID: |
3675541 |
Appl. No.: |
10/239602 |
Filed: |
November 14, 2002 |
PCT Filed: |
March 22, 2001 |
PCT NO: |
PCT/AT01/00086 |
Current U.S.
Class: |
417/420 ;
415/900; 417/423.1; 417/423.15 |
Current CPC
Class: |
A61M 60/419 20210101;
A61M 60/422 20210101; A61M 60/205 20210101; A61M 60/824 20210101;
A61M 60/148 20210101 |
Class at
Publication: |
417/420 ;
415/900; 417/423.1; 417/423.15 |
International
Class: |
F04B 017/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 24, 2000 |
AT |
A 510/2000 |
Claims
1. A rotary pump for moving blood and other shear-sensitive liquids
and having a rotor journaled hydraulically and if necessary
magnetically in a housing, characterized in that the rotor (1) has
flow-control surfaces (2, 4, 35, 33, 37, 41) for producing
centrifugal flow components (3) and flow components (4) directed
against the housing (30), the centrifugal flow components (3)
serving mainly for producing the externally effective throughput
and the flow components (5) directed against the housing serving
mainly for contact free journaling and stabilizing of the rotor in
the housing.
2. The pump according to claim 1, characterized in that the housing
(30) has a conical central part (16) and/or a hollow conical upper
part (15) and that the rotor (1) arranged between them is
conical.
3. The pump according to claim 1 or 2, characterized in that the
flow-control surfaces are formed as vanes (2 and 4) on a conical
inner and/or outer surface of the rotor.
4. The pump according to one of claims 1 to 3, characterized in
that the rotor (1) has flow-through rotor holes (18) on which the
flow-control surfaces (2, 4, 35, 33, 37, 41) are mounted.
5. The pump according to one of claims 1 to 4, characterized in
that edges of the rotor holes (18) are beveled to form flow-control
surfaces (35 and 37).
6. The pump according to one of claims 1 to 5, characterized in
that the rotor holes (18) extend to a lower edge (41) of the
conical sleeve and the lower edge (41) if necessary is formed as
flow-control surfaces for producing a drive component.
7. The pump according to one of claims 1 to 6, characterized in
that the rotor (1) is formed of two nested conical sleeves (31 and
32) between which extend vanes serving as flow-control surfaces
(33) for producing the centrifugal flow components (3) and that the
two conical sleeves (31 and 32) have rotor openings (18) and
selectively vanes (4) for producing the flow components (5)
directed against the housing.
8. The pump according to one of claims 1 to 7, characterized in
that the rotor (1) has at an inlet (13) and inlet opening (36) in
order to direct a portion of the incoming liquid against a point of
the conical central part (16) of the housing (30).
9. The pump according to one of the preceding claims, characterized
in that in the region of the lower edge (41) the rotor (1) is
provided with a plurality of rotor magnets (6) or a magnetic ring
that cooperates with magnets (10, 12) in the housing (30) and/or
with a magnetic drive.
10. The pump according to claim 9, characterized in that the
magnetic drive is formed by a stator (8, 12) with a surrounding
magnetic field.
11. The pump according to claim 9, characterized in that the
magnetic drive is formed by a disk rotor, a stator (38) being
provided with a rotating disk (24) with imbedded magnets (10) or
multiple magnetized regions.
12. The pump according to one of claims 1 to 11, characterized in
that the rotor magnets (6) and the magnetic-force producing
portions of the drive motor (8, 11, 12) are offset axially such
that the produce on the rotor (1) in addition to rotation energy a
force component effective axially ans serving to journal and/or
stabilize th rotor (1).
13. The pump according to one of claims 1 to 12, characterized in
that in addition to the drive a ring (27) of ferromagnetic iron or
permanent-magnet material is provided around the inlet (13) and in
the adjacent housing parts permanent or electromagnets (22, 23, 28)
are provided for additional magnetic. stabilization, and that
preferably to control this magnets additional sensors (42) are
provided for determining the exact position of the rotor (1) (FIG.
4).
14. The pump according to one of claims 1 to 13, characterized in
that the ring (27) of ferromagnetic iron around the inlet (13) has
a highly conductive surface coating (34), so that eddy currents and
magnetic fields therein center the rotor (1).
15. The pump according to one of claims 1 to 14, characterized in
that in order to rotate and stabilize the rotor (1) a peripheral
external stator (8) and an internal either stator (12) or motor
(26) or a disk-rotor motor (24, 29) with a magnetic disk (11, 24)
is provided, the internal components (12, 26, 29, 11, 24)
preferably being effective to produce the rotation energy and the
external stator for stabilizing the rotor (1).
Description
[0001] The present invention relates to a rotary pump for moving
blood and other shear-sensitive liquids with a rotor journaled
hydraulically and, if necessary, magnetically in a housing.
[0002] In order to pump blood and other shear-sensitive liquids,
rotary pumps and the like are used. In order to minimize
destruction of the blood, locally occurring speed differences
should not be too great as otherwise the corpuscular portion of the
blood is subjected to shear and as a result of the heat generated
by friction there is chemical degradation. In addition low-flow and
dead-water areas must be avoided in order to prevent deposits from
forming. When pumping blood, this is referred to as thrombosis- or
clot-forming.
[0003] This problem is particularly an issue in conventional
axle-type pumps since the axle is mounted in a standard seal, for
example in a needle bearing in the pump chamber, so as to produce
regions of high shear, friction and also often of low flow velocity
near the axle.
[0004] Therefore solutions have been suggested to provide pumps
without axles or mechanical bearings. Thus Akamatsu et al (see e.g.
Artificial Organs 1997, Vol. 21, No. 7, pp. 645-638) proposes a
pump where the rotor of a centrifugal pump is driven from one side
by a standard motor and is stabilized by a controlled
electromagnet. This pump above all is of complex construction and
there is a small gap between the rotor and the housing for proper
electrical operation.
[0005] Kung and Hart (Artificial Organs 1997, Vol. 21. No. 7, pp.
645-650) suggest a pump where the journaling is done purely
hydraulically by a geometric distribution of gaps above and below
the pump that are enlarged and decreased by axial movements of the
pump and the changes created thereby in pressure between the rotor
and the housing are used for stabilizing the pump. This system
functions only with a relatively narrow gap and can be made
unstable even if small amounts of blood form deposits.
[0006] Furthermore, Allaire et al (see e.g. Artificial Organs 1996,
Vol. 20, No. 7, pp. 582-690) suggest a centrifugal pump where the
rotor is journaled by a relatively expensive system of
electromagnets. In this system there are also small gaps and
control is complex.
[0007] Golding (U.S. Pat. Nos. 5,324,177 and 5,370,509) has in
addition suggested floating a conical rotor with helical arms on a
cone and centering of the rotor by support forces between a flatly
shaped rotor inner wall and a cone of the housing end wall. This
method requires above all the formation of very small gaps and thus
high shear forces, at the same times fluid tends to sit for quite
some time in the gap and the centering forces are very modest.
[0008] Finally Woodward et al (WO 00/12587) proposes a pump whose
rotor is hydrodynamically journaled, the rotation body having
several cylindrical elements whose angled ends form tapered gaps
together with the housing upper surface. The pressures that build
up therein or the liquid trapped between the tapering surfaces
serves to center the rotor. At the same time the conical shape of
the housing upper wall ensures radial centering. This invention
relates to a preferred system of stabilizing forces, but is
disadvantageous in that a small gap in the range of less then 0.3
mm is used which creates considerable shear and which can lead to
substantial changes in the flow parameters if there is any
deposition of solids. In addition the rotor shapes suggested there
create a multiplicity of dead spots and stagnant zones.
[0009] The present invention therefore has the object of overcoming
these disadvantages. Mechanical depositions, dead-water zones or
zones of reduced flow velocity and small gaps are to be avoided.
The number of parts should be small and the construction
simple.
[0010] The invention is characterized in that the rotor has
flow-control surfaces for producing centrifugal flow components and
flow components directed against the housing, the centrifugal flow
components serving mainly for producing the externally effective
throughput and the flow components directed against the housing
serving mainly for contact-free journaling and stabilizing of the
rotor in the housing. Further preferred features are that the
housing has a conical central part and/or a hollow conical upper
part and that the rotor arranged between them is conical.
Furthermore the flow-control surfaces are formed as vanes on a
conical inner and/or outer surface of the rotor. Preferably the
rotor has flow-through rotor holes on which the flow-control
surfaces are mounted. Further features can be seen in the claims,
the description, and the drawing.
[0011] The invention is described in the following with reference
to seventeen figures. FIGS. 1 to 5 show cross sections through
various embodiments of the pump and FIG. 6 an oblique view of a
rotor. FIG. 7 is a section through the rotor and FIG. 8 an angle
view of the section according to line V-V of FIG. 7. FIGS. 9 and 11
show rotors in an oblique view and FIGS. 12, 12, 13, and 14 the
respective sections. FIGS. 15 shows a further embodiment of the
rotor and FIGS. 16 and 17 show possible cross sections through the
rotor vane. All figures are schematic.
[0012] FIG. 1 shows a section through the pump. The rotor 1 has as
flow surfaces 2 and 4 vanes that produce centrifugal flow
components 3 and flow components 5 directed against the housing. To
this end these flow surfaces 2 and 4 are formed on a conical base
17 which has rotor openings 18 for flow to the inner vanes 4. This
hollow conical rotor 1 rotates in a pump housing 30 comprised of a
housing lower part 19 with a conical middle part 16 and a hollow
conical upper part 15, centering of the hollow conical rotor in the
middle part 16 of the housing lower part 19 being effected by the
flow components 5 directed against the housing, this flow being
preferably axially against the conical upper surface of the middle
part 16. This centering can however also be wholly or additionally
effected by flow components (5) directed against the housing or
centrifugally (3) against the hollow conical upper part 15. A
spiral-shaped outlet passage 20 in the lower housing part 19 leads
to an outlet 14. The rotor holds rotor magnets 6 that preferably
transfer rotation energy and that can be individual or formed by a
continuous magnetic ring. These rotor magnets work as shown in FIG.
1 with a stator 12 inside the housing lower part 19 having coils 9
creating a rotating magnetic field. An axial offset of the rotor
magnets 6 and stator 8 causes the coupling force 21 to be effective
at an angle and provide an axial component for additional
stabilizing of the rotor 1, the direction of this axial component
being upward or downward by appropriate offset of the stator 12
upward or downward. The rotor 1 has at an inlet 13 an inlet opening
36 that distributes the incoming liquid to both sides of the rotor
and against the point of the cone-shaped middle part 16.
[0013] As shown in FIG. 2, the drive can also be an electric motor
26 which drives a rotating disk 24 with magnets 10 by means of a
shaft 25. This embodiment has the advantage that no electrical
energy is used to journal the rotor and as a result the axial
offset of the disk 24 ensures an axial component for the magnetic
force 21.
[0014] FIG. 3 shows that the drive can be a disk-rotor motor where
the disk 11 with imbedded magnets 10 or a similar multipolar
magnetization with a journaled axle 29 simultaneously serves as
rotor for the motor-stator 44 and for transmitting magnetic energy
5 to the rotor 1.
[0015] As shown in FIG. 4 the drive 7 can be an externally
effective stator 8 that is used instead of or in addition to an
internal stator 12. In addition for hydraulic stabilization of the
rotor 1 all embodiments of the drive also have a magnetic
stabilizer near the inlet 13, a ferromagnetic or permanent-magnet
ring 27 imbedded in the rotor 1 being provide internally and/or
externally with permanent or electromagnets 22 and 28 with coils 23
so as to compensate for any instability caused by flow past the
rotor. The ferromagnetic ring 27 can be provided externally with an
electrically very conductive layer 34 in order to facilitate the
formation of electrical eddy currents which create magnetically
centering forces.
[0016] In addition a combination of inside and outside drive
systems (stators 8 and 19) is possible on the lower edge of the
rotor 1, one of which preferably serves for transmitting rotation
energy and the other for stabilization purposes.
[0017] The position (running characteristic) of the rotor can for
example be determined by appropriate position sensors as shown
schematically in FIG. 4 at 42 in various positions. For example
Hall-type sensors can be used. In order to determine position
however induced voltages or the effect of high-frequency feed
voltages in the coils can be measured and evaluated, eliminating
the need of any further sensors.
[0018] Various embodiments are described in FIGS. 5 to 15.
[0019] FIG. 5 shows an embodiment of the pump with a rotor 1 that
is formed of two superposed conical sleeves 31 and 32 that are
connected together by centrifugal vanes or flow surfaces 33. Rotor
openings 18 and the outer vanes 4 serve to produce the flow
component 5 against the upper part 15 of the housing as well as
against the conical middle part 16 of the lower housing part 19. In
this manner the rotor is hydrodynamically stabilized in the
housing.
[0020] FIGS. 6 to 8 show in oblique view, top view, and section the
basic shape of a rotor 1 in an embodiment with a conical base part
17 on whose outside are mounted vanes serving as flow surfaces 2
for preferably producing centrifugal flow components. These vanes
can have an arched portion 39 known in centrifugal blood pumps and
that allows the vanes to be oriented against the rotation direction
40. The base body 17 has at the inlet side the inlet opening 36
that makes possible direct flow into the point of the conical
central part 16 of the housing lower part 19. The base body is
further formed with rotor holes 18 through which the liquid can be
move by the vanes 4 against the housing middle part 16. The effect
of the vanes 2 and 4 can be increased by an angling 35 of the
opening 18 or when the conical body 17 is thick enough even
replaced, in which latter case the vanes 2 and 4 can be eliminated.
The flow surfaces are thus only formed by an angling of the edges
of the rotor openings 18.
[0021] FIGS. 9 and 10 show in angled view and section the also
possible variant whereby the vanes 4 for producing the flow
component 5 against the housing are on the outer side of the
conical base body 17 and the vanes 2 for preferably producing
centrifugal flow components 3 are on the inside of the base body
17.
[0022] These two described opposite rotor constructions are made
possible by as described above an upward or downward axial offset
of the rotor magnets 6 and the drive magnets 8, 12, or 24 and the
thereby achieved equally selective upwardly or downwardly directed
axial components of the magnetic forces 21, see FIGS. 1 to 5.
[0023] FIGS. 11 to 13 show a rotor with two nested conical sleeves.
It makes possible flow against both housing walls 16 and 19. It is
shown in cross section in FIG. 5 and is shown in detail in angled
view in FIG. 11, in FIG. 12 in top view, and in FIG. 13 in a
section transverse to the axis of the pump. Here the inner conical
sleeve 31 and the outer conical sleeve 32 are connected together by
struts 33 that are also effective as flow-control vanes. The rotor
holes 18 have edge bevels or vanes (4) that produce the flow
component directed against the housing.
[0024] In addition this arrangement of the two flow-control
surfaces (2 and 4) in combination with the angling 35 of the rotor
hole 18 in the conical sleeve can be formed together to a single
vane formation as shown in FIG. 14. This formation is also possible
with superposed conical sleeves.
[0025] Finally the pump according to FIG. 15 also has a rotor where
the individual vanes 37 are freestanding without a continuous
conical base body. These vanes are either of a wedge-shaped profile
(see FIG. 16) or have an angled shape (see FIG. 17), a substantial
beveling 37 forming flow-control surfaces. The rotor holes 18
extend to the lower edge 41 of the rotor 1. This lower edge can
also extend at an angle to the flow direction so that it serves as
a flow-control surface for reducing the drive component or a flow
component for the liquid flow. The ends of the vanes can carry
magnets 38 for the drive and additional magnetic journaling.
[0026] In FIGS. 1 to 5 the outlet is always underneath the lower
edge 41. When the outlet 14 should be set higher, generally in the
plane of the lower edge 41 of the rotor 1, ti can be advantageous
to provide two symmetrically opposite outlets or one outlet with
two parts, in order to stabilize flow of the liquid.
* * * * *