JPWO2008053818A1 - Spiral pump for blood - Google Patents

Abstract

[Summary] [Problem] To achieve a rotary pump that can open the inflow port on the peripheral side and does not apply eccentric torque to the rotating shaft. A disk-shaped rotating body 3 having a liquid permeation hole in an outer peripheral portion and an opening on one side surface of the rotating body 3 toward the outer peripheral portion, and a cross-sectional area is reduced in accordance with the rotating direction of the rotating body. A spiral inflow passage 2 is provided. [Selection] Figure 3

Description

  The present invention relates to a spiral flow pump having a new structure suitable for blood.

  There are various types of liquid pumps, but centrifugal type centrifugal pumps, axial flow pumps, and diagonal flow pumps are rotary types, rotary pumps and roller pumps are volume type, and discs are special types. There are friction pumps that utilize the friction between the liquid and the liquid. In the centrifugal pump, an inflow port is opened at the center of the impeller in the axial direction, and an outflow port is opened at the peripheral side surface. In the axial flow pump, the inflow and outflow ports open before and after the impeller in the axial direction. A mixed flow pump is similar to a centrifugal pump.

  As a blood pump, for example, for an artificial heart, the implant volume is small, and at least the inflow port, preferably the outflow port, is opened on the peripheral side surface of the impeller so that there is no obstacle to the blood flow piping. It is necessary to be. These pumps have a uniform pressure distribution in the rotational direction of the impeller, so no eccentric torque is applied to the shaft, but none of the inflow ports can open to the peripheral side, so for example, for use in a fully-replaceable artificial heart In some cases, there is an inconvenience in terms of assembling, and there is a problem that the embedding volume increases because it is necessary to cope with the use of pipes such as bends and elbows. In addition, rotary pumps, roller pumps, and friction pumps can open the inflow port on the peripheral side, but in these pumps, the pressure distribution in the rotational direction of the rotating body is not uniform, and therefore eccentric torque is applied to the drive shaft. It takes. Therefore, there is a problem that a strong bearing mechanism is required to improve the wear resistance of the drive shaft.

  On the other hand, Patent Document 1 describes a fuel pump that pumps fuel to a fuel tank of an automobile as a so-called side channel pump. FIG. 13 is a sectional view thereof, wherein 1 is an inflow port, 2 is an inflow channel, 3 is an impeller (rotary body), 4 is an outflow channel, and 5 is an outflow port. The inflow path 2 connected to the outflow port 1 is continuously reduced in the flow direction, and the outflow path 4 connected to the outflow port 5 is continuously enlarged in the flow direction. The impeller 3 is partitioned by the blades of the impeller 3 to form a chamber, and the inflow passage, the chamber, and the outflow passage form a pressure feeding chamber. By the rotation of the impeller 3 in the direction of the arrow, the overflow from the inflow passage through the chamber to the outflow passage The liquid is pumped from the inflow port 1 toward the outflow port 5.

The side channel pump is suitable as a blood pump in that the inflow port can be opened to the peripheral side surface, but there is also a problem that an eccentric torque is applied to the shaft.
JP-T-2006-526110

  An object of the present invention is to eliminate such problems in the conventional rotary pump and make the side channel pump more suitable for blood.

  The present invention provides a disc-shaped rotating body having a liquid passage in the outer peripheral portion, and opens on one side surface of the rotating body toward the outer peripheral portion, and has a cross-sectional area over substantially the entire circumference according to the rotating direction of the rotating body. A spiral flow pump for blood, or an opening on the other side surface of the rotating body toward the outer peripheral portion, and substantially the entire circumference according to the rotation direction of the rotating body. The spiral flow pump for blood, characterized in that it has a spiral outflow passage whose cross-sectional area increases over the area, and preferably the rotary body has a shape in which a radial plate-like member is attached to the outer periphery of the disc. In the blood spiral pump, the plate-like member has a planar shape or a curved shape.

Alternatively, in the present invention, the stator is attached near the inner rotation center of the inflow passage or the outflow passage, and the portion near the rotation center of the rotating body is used as a space, and the stator is disposed outside the stator. And the above-described spiral pump for blood, in which a motor is constituted by a rotor.
Note that “almost all around” is theoretically spiral around the entire circumference, but due to processing problems, it is possible that a slightly non-spiral portion remains at the end of the flow path. Because.

  According to the present invention, an inflow port can be opened on the peripheral side surface of the rotating body, and an eccentric torque is not applied to the shaft, and a blood pump that can be used for a long time is realized with a compact and excellent sealing performance. Has an excellent effect.

  The basic configuration of the present invention consists of two element principles. One is a pump principle composed of a rotating body and a spiral inflow passage extending almost all around, and the other is a spiral principle extending almost entirely around the pump principle to prevent eccentricity of the rotational shaft torque in addition to this pump principle. It is an outflow channel. Since the rotating body is for moving the liquid from the inflow path side to the outflow path side, the rotating body only needs to have a structure that moves the liquid in the rotation direction and allows the liquid to pass through the rotating body in the axial direction. For example, a disk shape having a passage such as a plurality of liquid permeation holes in the outer peripheral portion or a shape in which a radial plate-like member is attached to the outer periphery of the disk is preferable. It is preferable to incline with respect to the rotation axis so that a component force in the axial direction is generated in the internal liquid with rotation.

  A first embodiment of the present invention will be described with reference to the drawings. 1 is a sectional view of a spiral flow pump of the embodiment, FIG. 2 is an exploded perspective view of the spiral pump, FIG. 3 is a perspective view of only a main part, 1 is an inlet port, 2 is a spiral inlet channel 3 is a rotating body, 31a is a radial plate-shaped member provided on the outer periphery of the disk of the rotating body, 32 is a conduction hole provided in a disk portion of the rotating body, 4 is a spiral outflow path, 5 Is an outflow port, 6 is a rotating shaft of the rotating body 3, 7 is a bearing, and 8 is a seal member of the bearing portion. The spiral inflow passage 2 and outflow passage 4 are opposed to the plate-like member 31a of the rotating body 3. As shown in FIG. 1, since the inflow port 1 and the outflow port 5 face in the same direction, it is easy to adopt for an artificial heart or the like.

  FIG. 4 is a conceptual diagram in which the inflow path 2, the rotating body 3, and the outflow path 4 shown in FIGS. 1 to 3 are developed in the circumferential direction, and the cut portions A and B at both ends of FIG. 4 are actually continuous. If the rotation direction of the rotator 3 is changed from the right to the left as shown by the arrow, the plate-like member 31a also moves in the same direction, so that the liquid in the middle of the plate-like member 31a moves and is in contact therewith. The liquid on the inflow path side also tries to move in the same direction due to friction with the liquid between the plate-like members, but the cross section of the inflow path becomes smaller as it moves, so that the liquid is gradually pushed out to the outflow path side. It moves to the outflow path 4 side from 2 side. Thus, since the movement of the liquid depends on the friction between the liquids, the spiral flow pump of the present invention is effective for a viscous liquid such as blood.

  Furthermore, consideration must be given to the blood pump so as not to generate high heat in the system or cause clogging. In FIG. 1, 7 is a rolling bearing. A metal collar is inserted over the outer race, and a seal member having a V-shaped lip fitted on the rotating shaft 6 is in contact with the outer collar to seal the liquid against the bearing. The lip and the collar are in sliding contact, but in order to prevent the generation of localized frictional heat, the disc part of the rotating body 3 is used so that a part of the liquid in the pump flows for the purpose of cooling or lubricating this part. A conduction hole 32 is provided in the inner wall. In addition, in order to prevent local heat generation and blood destruction due to high-speed flow, avoid the formation of extremely narrow cross sections in the flow path, and the plate-like member and surrounding casing even if the efficiency of the pump is somewhat sacrificed It is necessary to make the gap between and the like large, for example, about 0.3 to 0.5 mm. Moreover, in order to prevent generation | occurrence | production of rust etc., as for the material of pumps, such as a casing and an impeller, resin, such as polycarbonate, and non-rusting metals, such as stainless steel and titanium, are preferable.

  The pump needs to perform rotation speed control in order to realize a situation where the flow rate is constant or the pressure is constant according to the purpose. In FIG. 1, 9 is a drive shaft, 91 is a coupling attached to the tip thereof, 92a is a magnet attached to the coupling, and 92b is a magnet embedded at a position corresponding to the magnet 92a of the disk portion of the rotating body 3. It is. Of course, a motor is attached to the drive shaft 9, but the illustration is omitted. By driving by using the remote force by the magnet in this way, the rotating shaft 6 is sealed in the casing, the liquid is prevented from leaking without providing the through portion, and the driving portion such as a motor is attached to and detached from the pump body. Making it easy.

  The effect of the pump of this example shown in FIGS. The rotating body including the pump chamber, the spiral inflow passage, the outflow passage, and the plate member was manufactured by cutting acrylic resin with a three-dimensional numerical control processing machine. The pump chamber has an outer diameter of 68 mm and a width of 14 mm. The pump chamber was divided into two parts and formed integrally with the spiral inflow path and outflow path, respectively. The inflow path and the outflow path have the same shape, and are arranged to face the plate member of the rotating body with the pump chamber interposed therebetween. The spiral inflow and outflow channels are 68mm outside diameter, 48mm inside diameter, and the shape at the inlet and outlet is a square with a side of 10mm and is arranged in a clockwise direction. is there. The cross-sectional area of the channel gradually decreases, but the pitch is 10 mm per revolution, making one round.

  The rotating body arranged in the pump chamber is disk-shaped, the outer diameter of the central disk part is 48mm, the maximum outer diameter with a plate-like member provided on the outside is 67mm, and the width (thickness) is 13mm. A gap of 0.5 mm was provided between In the central disc part, six neodymium iron magnets (diameter 10mm, thickness 6mm) were embedded so that adjacent radial magnets had magnetization directions opposite to each other in the axial direction. It was driven by a motor placed outside through magnetic coupling with a similar disk installed outside the pump. The rotating body consists of a metal shaft (diameter 6 mm, length 25.5 mm) attached to the center of the rotating body, a ball bearing (inner diameter 6 mm, outer diameter 19 mm, Supported by 2 pieces (width (height) 6mm).

The characteristics of the pump were measured using a Donovan mock circuit. The capacity of the circuit is about 4L. An electromagnetic flow meter (Nihon Kohden main body MFV-2100 and FF-106T) was used to measure the flow rate. As the liquid, a 0.9% saline solution was used assuming a physiological saline solution. Diaphragm pressure sensor (manufactured by Nihon Kohden, main unit MEG-6108, amplifier unit AP-610J, probe)
Using P10EZ-1), the differential pressure was measured in the vicinity of both ports. In order to clarify the pure hydraulic performance of the prototype pump, the pump output relative to the shaft input was measured and the pump efficiency was calculated. The motor was driven by a three-phase DC brushless motor FBM5120W-A manufactured by Oriental Motor Co., Ltd., at a constant rotation speed by an inverter manufactured by the same company. The shaft torque was measured with Ono Sokki Torque Detector SS-005 and Torque Converter TS-2600.

  The results of the head test of the prototype pump performed with the above configuration will be described. The planar plate-like members are 12 pieces of 13 mm × 10.5 mm and a thickness of 2 mm. In this case, lift is not generated in principle, and since the spiral radius of the spiral inflow path and the spiral outflow path are the same, there is no effect of centrifugal force. Therefore, the pump has a structure in which the pump action can be obtained only by the frictional force. In addition, since both sides are symmetrical with respect to the rotating body, the flow in both forward and reverse directions can be obtained by reversing the rotation of the motor. FIG. 5 and FIG. 6 show the pump characteristics and efficiency at the rotation speeds of 1000 rpm, 1200 rpm, 1500 rpm, and 1700 rpm, respectively, when the motor is operated at a constant speed. The horizontal axis is the pump output, that is, the flow rate (L / min), the vertical axis in FIG. 5 is the load pressure (pressure difference, mmHg), and the vertical axis in FIG. 6 is the efficiency (%). A load pressure of 146 mmHg was obtained at a flow rate of 10 L / min at 1500 rpm. The deadline pressure was 105 mmHg, 152 mmHg, 237 mmHg, and 309 mmHg at 1000 rpm, 1200 rpm, 1500 rpm, and 1700 rpm, respectively. Efficiency increased with increasing flow rate and was up to 32%. The load pressure had a tendency to decrease linearly with respect to the flow rate, and was close to that of a friction pump or an axial flow pump.

  A second embodiment of the present invention will be described with reference to FIGS. Since the plate-like member in the present invention moves the liquid in the rotation direction of the rotating body 3, it may be a flat plate attached in a radial direction to the disk as shown in the first embodiment. As shown in FIGS. 7 and 8, it is desirable to give the plate-like member 31b a curved shape if the pumping action is to be further exerted using lift. 7 is a perspective view of the rotating body, FIG. 8 is a developed view of the rotating body in the circumferential direction, and 31b is a curved plate member. When the plate-like member has a curved surface shape, the liquid moves in the rotational direction (FIG. 7, right to left in FIG. 7) by the generated lift, and simultaneously moves in the axial direction according to the curved shape of the plate-like member 31b. Along with this, the liquid flows out in a spiral flow in the outflow path.

As described above, the spiral flow pump of the present invention exerts the pump action by the frictional force of the liquid or the turbine force. Therefore, the shape of the plate-like member is changed to these planes or curved surfaces, or the mounting angle is changed. Therefore, various pumping actions can be expected.
The result of the verification test of the spiral flow pump of Example 2 will be described. The plate-like member is an airfoil that generates lift. The size of the rotating body was the same, and the plate member was 12 blades occupying 20 ° per sheet. The angle formed by the tangent line between the rotating surface and the upper and lower surfaces of the blade was designed to be proportional to the circumference. The angle formed by the tangent between the rotating surface and the blade upper surface was 0 ° at the inlet and 82 ° at the outlet, and the angle formed by the tangent between the rotating surface and the blade lower surface was 60 ° at the inlet and 85 ° at the outlet. The pump characteristics and efficiency at 1000 rpm, 1500 rpm, and 1700 rpm are shown in FIGS. The horizontal axis is the pump output, that is, the flow rate (L / min), the vertical axis in FIG. 9 is the load pressure (pressure difference, mmHg), and the vertical axis in FIG. 10 is the efficiency (%). A load pressure of 127 mmHg was obtained for a flow rate of 10 L / min at 1500 rpm, and the closing pressures were 107 mmHg, 242 mmHg, and 316 mmHg at 1000 rpm, 1500 rpm, and 1700 rpm, respectively. Efficiency increased with increasing flow rate, up to 30%. Like the impeller 3 described above, the load pressure has a tendency to decrease linearly with respect to the flow rate, and similarly has characteristics similar to those of a friction pump and an axial flow pump.

  As is clear from the above experimental results, the spiral flow pump of the present invention is a highly efficient pump of this size, and is a small high performance pump.

  A third embodiment of the present invention will be described with reference to FIG. This figure is an exploded perspective view of the spiral pump for blood according to the embodiment, similar to FIG. 3 shown above. The plate-like member 31b has a curved surface shape similar to that shown in FIG. 7, but may have a planar shape. The difference from the first and second embodiments is that a driving motor (not shown in the first and second embodiments) is taken into the pump and the rotating shaft and the bearing are eliminated. In FIG. 11, S is a stator of the motor and the rotating body 3A is a rotor of the motor. That is, the stator S is an iron core and a coil wound around the iron core, and is attached to either the inflow path or the outflow path, in this example, at a position closer to the inner center of the outflow path. Further, the rotor has a structure in which the center shown in FIG. A permanent magnet is arranged inside. Therefore, the stator S is located in the cylindrical space of the rotor, and a synchronous motor is constituted by the stator coil and the rotor permanent magnet. The rotor is supported without contact by dynamic pressure. It is desirable to cover the stator core with a thin stainless steel plate to prevent rust.

  The shape and dimensions of the pump itself are almost the same as the previous examples, but the outer diameter is 68 mm, the width is 14 mm, the inflow path 2 and the outflow path 4 are the same shape, the outer diameter is 68 mm, the inner diameter is 48 mm, and the inflow port 1. The shape at the outflow port 5 is a square with a side of 10 mm. The rotor 3A has an outer diameter of 67 mm, an annular part has an outer diameter of 48 mm, a width of 13 mm, and a gap of 0.5 mm is provided between the rotor 3A and the pump chamber. The inner ring of the rotor 3A is embedded with six neodymium iron magnets that are radial and adjacent magnets have magnetization directions opposite to each other in the axial direction.

  When the plate-like member has a planar shape, the pump of this example maintains a flow rate of 20 L / min per load pressure of 170 mmHg at a rotational speed of 2000 rpm, and the pump efficiency at that time is 32%. It was. This is an unusually high output for a blood pump of this size, and greatly exceeds the performance required by the National Institute of Preventive Health (NIH) (average aortic pressure 110 mmHg, left heart flow rate of 8 L / min or more). .

In this embodiment, a sealing motor can be further enhanced by incorporating a drive motor in the pump, and since there is no shaft or bearing, there is no occurrence of eccentric torque or high local heat, which is suitable for blood. However, in a disposable application such as a heart-lung machine in an operating room, such a motor built-in type is unnecessary, and a motor detachable type as in Examples 1 and 2 is suitable.
In the helical flow pump of the present invention, since the pumping action is performed by the spiral inflow path and the rotating body over almost the entire circumference, it is possible to realize a new rotating pump in which an input port opens on the peripheral side surface of the rotating body. In addition, since this pump approximates the configuration of a turbo pump, it is possible to prevent eccentricity of the rotating shaft torque by a hydrodynamic method. If a spiral outflow path is provided in addition to the spiral inflow path, this spiral flow pump moves the liquid in the rotational direction by frictional force, so the rotational direction is both in the inflow path 2 and in the outflow path 4. A pressure gradient is generated. In FIG. 4, this pressure gradient increases from right to left in the drawing, but the pressure distribution in the rotational direction applied to the rotating body 3 is the difference between the pressure in the spiral outflow passage 4 and the pressure in the spiral inflow passage 2. (Pressure difference). Therefore, if the same shape is used for the spiral inflow path 2 and the spiral outflow path 4, the pressure difference becomes constant, so the pressure distribution in the rotational direction applied to the rotating body 3 becomes uniform, and the rotating shaft 6 is eccentric. No torque is applied.

  Further, in the spiral flow pump of the second embodiment, the liquid moves in the rotational direction and simultaneously moves in the axial direction according to the curved surface shape of the plate member. In this case, since the cross-sectional area of the spiral inflow passage 2 decreases uniformly with the movement of the liquid, the pressure distribution in the inflow passage 2 becomes uniform. Further, since the cross-sectional area of the spiral outflow passage 4 uniformly increases as the liquid moves, the pressure distribution in the outflow passage 4 is also uniform. Therefore, the pressure distribution in the rotation direction applied to the rotating body 3 is uniform, and no eccentric torque is applied to the rotating shaft 6.

When changing the shape and structure of the plate-like member and using both frictional force and lift force to exert the pump action, the pressure distribution in the pump is also intermediate between the above two, but both of them rotate the rotating body Since the pressure distribution in the direction is uniform, no eccentric torque is applied to the rotating shaft.
In addition, although the example of the ball bearing was shown as a bearing, since eccentric torque is not applied to a rotating shaft, a non-contact type bearing can also be used. As a non-contact type bearing, a magnetic bearing, a fluid bearing, and the like are known. For example, DLC (Diamond) has recently been used as a dynamic pressure type liquid lubricated bearing for introducing a liquid to a sliding surface to float.
Excellent bearing materials such as carbon (diamond-like carbon coating) have been developed, and a long life of about 30 years can be expected at a thickness of several tens of μm for light loads. Moreover, there are no problems such as sealing and cooling as described above.

In addition, the inflow path and the outflow path are not limited to a single helix of only one line at 360 degrees, and multiple helixes such as double or triple may be used. As a result, even if the shapes of the spiral inflow path and the outflow path are different, eccentric torque can be prevented from being applied to the rotating shaft.
FIG. 12 shows an example of a spiral pump for blood in the case of a double helix. FIG. 5 is a developed conceptual diagram corresponding to FIG. 4 shown above.

  In addition, the example of the pump in which the inflow path and the outflow path are symmetrically arranged has been described above. However, depending on the application, the outflow path may not necessarily be provided, and only the inflow path and the rotating body act as a pump.

It is sectional drawing of the helical flow pump of the 1st Example of this invention. It is a perspective view which decomposes | disassembles and shows the spiral flow pump of FIG. It is a perspective view which shows only the principal part of the spiral flow pump of FIG. It is the expanded view which expand | deployed the inflow path, the rotary body, and the outflow path in the spiral flow pump of 1st Example of this invention to the circumferential direction. It is a graph which shows the pump characteristic of the spiral flow pump of 1st Example of this invention. It is a graph which shows the pump efficiency of the spiral flow pump of 1st Example of this invention. It is a perspective view which shows the rotary body of the 2nd Example of this invention. Similarly, it is the development which developed the rotating body of the 2nd example of the present invention in the circumference direction. It is a graph which shows the pump characteristic of the spiral flow pump of the 2nd Example of this invention. It is a graph which shows the pump efficiency of the spiral flow pump of the 2nd Example of this invention. It is a perspective view which decomposes | disassembles and shows the helical flow pump of the 3rd Example of this invention. It is the expanded view developed in the circumferential direction when the inflow path and the outflow path in the spiral flow pump of the present invention are double spirals. It is sectional drawing which shows the principal part of a conventionally well-known fuel pump.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inflow port 2 Inflow path 3 Rotating body 3A Rotor (rotating body)
4 Outflow path 5 Outflow port 6 Rotating shaft 7 Bearing 8 Seal member 9 Drive shaft 31, 31a, 31b Plate member 32 Conducting hole 91 Coupling 92a, 92b Magnet S Stator

Claims (10)

  A disk-shaped rotating body having a liquid passage in the outer peripheral portion, and a spiral opening in one side surface of the rotating body toward the outer peripheral portion, and reducing the cross-sectional area over the entire circumference according to the rotating direction of the rotating body. Spiral flow pump for blood characterized by having an inflow channel in the shape of a tube.   2. The spiral flow-out channel having an opening toward the outer peripheral portion on the other side surface of the rotating body and having a cross-sectional area increasing substantially over the entire circumference in accordance with the rotation direction of the rotating body. The spiral pump for blood described.   The blood spiral flow pump according to claim 1, wherein the rotating body has a shape in which a radial plate-like member is attached to an outer periphery of a disc.   The spiral flow pump for blood according to claim 2, wherein the rotating body has a shape in which a plate member in the radial direction is attached to the outer periphery of the disc.   The spiral flow pump for blood according to claim 3 or 4, wherein the plate-like member has a planar shape.   The helical flow pump for blood according to claim 3 or 4, wherein the plate-like member has a curved shape.   The blood spiral pump according to any one of claims 1 to 6, wherein the inflow path or the outflow path has a multi-spiral shape in which a plurality of spirals having different phases are overlapped.   The rotating shaft and bearing of the said rotary body are sealed with the ring which has a V-shaped lip, The conduction hole which leads to this seal | sticker part is provided in the said rotary body in any one of Claim 1 thru | or 7. A spiral pump for blood.   The blood spiral flow pump according to any one of claims 1 to 8, wherein the bearing that supports the rotating shaft of the rotating body is a non-contact type bearing.   A stator is mounted near the inner rotation center of the inflow path or the outflow path, and a rotor is used as a space near the rotation center of the rotating body, and the motor is constituted by the stator and the rotor so as to be disposed outside the stator. The spiral pump for blood according to any one of claims 1 to 7.

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