JP3247717B2 - Blood pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blood pump for transporting blood, and more particularly to a centrifugal blood pump suitable for use in a blood extracorporeal circuit.

[0002]

2. Description of the Related Art As a pump device for transporting a biological fluid such as blood or plasma, those described in U.S. Pat. No. 4,589,822 and Japanese Patent Publication No. 57-23114 are known. These are all turbo-type pumps that pump blood by centrifugal force.The former generates centrifugal force by rotation of a general open type multi-blade vane, and the latter generates frictional force between multiple conical rotators. Is used to generate centrifugal force.

[0003] In the transfer of blood by a blood pump, destruction of useful cells (formation components) such as blood cells and platelets in blood and deterioration of the function are minimized, and blood reaction is caused by foreign substance reaction and temperature rise. It is important to prevent the blood from coagulating, to minimize the amount of blood (priming amount) filled in the pump, and to increase the pump efficiency.

[0004] Among these problems, it is known that the destruction and function of cells in blood are largely caused by disturbance of blood flow in a pump during blood feeding. In this regard, the blood pump disclosed in Japanese Patent Publication No. 57-23114 is a pump that applies a centrifugal force to a fluid by a frictional force between a plurality of conical rotators, and that flows through a blood passage between the rotators. It is known as a pump that is less likely to cause turbulence and thus less destroys cells (Hydrodynamic and Hemodynamic Evolution of Rotary Blood Pumps: Inter Workshop on Rotary Blood Pumps Vienna 1988 76-
Page 81 (Hydrodynamical and Hemodynamical Evalua
tion of Rotary Blood Pumps: Inter.Workshop on Rotar
y Blood Pumps Vienna 1988pp76-81)).

[0005] However, this blood pump is inferior in pump efficiency to a pump using a general vane.
In order to generate an equivalent head compared to a vane type pump of the same size, a considerably higher rotation speed is required. For this reason, there is a drawback that local heat is generated in the seal portion of the rotating shaft, and the blood around the seal is denatured and coagulated.

Further, this blood pump requires a plurality of rotators in order to obtain a discharge amount equivalent to that of a vane type pump of the same size, so that the capacity of a space in a casing for accommodating these rotators increases. There is a disadvantage that the amount of blood (priming amount) filled in this space increases.

On the other hand, the blood pump disclosed in US Pat. No. 4,589,822 uses an open multi-blade vane having a large opening at the center in order to reduce local heat generation at the shaft seal. It has been proposed to increase the flow rate of blood around the seal portion and to add a heat sink structure.

[0008] However, in such an open type multi-vane blood pump, eddy current or backflow occurs when blood flows between the vanes, and the flow is easily disturbed. There is a problem that the function of platelets is liable to be reduced and is not suitable for long-term use.

[0009] In general, if the size of the blood pump is increased, a high head can be obtained at a lower rotation speed, and the reduction of the rotation speed suppresses cell destruction and blood coagulation.
At the same time, the amount of blood (priming amount) to be filled in the pump increases, so that the above-mentioned problems cannot be satisfied.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a blood pump which suppresses the destruction of cells in blood and reduces the function thereof without increasing the amount of priming, and exhibits excellent pump characteristics at low rotation. Is to do.

[0011]

This and other objects are achieved by the present invention which is defined below as (1) to (6).

(1) A substantially circular chamber is formed inside,
A blood outlet port communicating with this chamber, and a housing communicating with the chamber and having a blood inlet formed at the center thereof;
An opening formed in the center portion facing the blood introduction port,
A blood pump having a plurality of blood passages arranged radially from the opening and housed concentrically in the chamber and a bearing for rotatably supporting the rotator in the room. Wherein a projection protruding toward the blood inlet is provided at the center of the rotating body, and a first guide surface facing the outer circumference of the projection is provided on an inner peripheral surface of the opening. Further, a second guide surface facing the outer peripheral surface of the projection is provided at a connection portion between the blood inlet and the inner surface of the housing, and the outer peripheral surface of the projection and the first and second guide surfaces are provided. Between the blood introduction port and the blood passage to form an expanded flow path for distributing the blood flow to each blood passage, wherein the first guide surface is an extension of the second guide surface, or A blood pump located outside the blood pump.

(2) The angle defined by the first guide surface and the center axis of the rotating body is equal to or larger than the angle formed by the second guide surface and the center axis of the rotating body. The blood pump as described.

(3) The above-mentioned (1) or (2), wherein the blood passage is formed such that a cross-sectional area thereof is substantially constant or continuously reduced along a flow direction of blood in the blood passage. The blood pump according to (1).

(4) The blood pump according to any one of (1) to (3), wherein the blood passage is tubular.

(5) The blood pump according to any one of (1) to (4), wherein the blood passage has a linear shape.

(6) The blood passage according to any one of (1) to (5), wherein a center line of the blood passage is formed at an angle of 75 to 90 ° with a center axis of the rotating body. Blood pump.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a blood pump according to the present invention will be described in detail based on a preferred embodiment shown in the accompanying drawings.

FIG. 1 is a sectional side view showing a configuration example of the blood pump of the present invention, and FIG. 2 is a sectional view taken along line AA in FIG. As shown in these figures, the blood pump 1 of the present invention has a substantially circular chamber 23 therein, and a blood inlet 21 and a blood outlet 2 communicating with the chamber 23.
2, a rotating body 3 having a plurality of blood passages 34 radially arranged from the vicinity of the center and housed concentrically in the chamber 23, and the rotating body 3 in the chamber 23. And a bearing portion 4 that is rotatably supported.
Hereinafter, each component requirement will be described.

As shown in FIG. 1, the housing 2 has a substantially cylindrical shape as a whole, and has a flat and substantially circular chamber 23 formed therein. A blood inlet 21 communicating with the chamber 23 is provided at the center of the top of the housing 2 so as to protrude in the axial direction of the chamber 23, and a blood outlet 22 communicating with the chamber 23 is provided on a side of the housing 2. The chamber 23 is provided so as to protrude in a tangential direction. Blood is introduced into the chamber 23 from the blood inlet 21 and is discharged from the blood outlet 22.

In the chamber 23 of the housing 2,
A flat disk-shaped rotating body 3 is rotatably housed concentrically with the chamber 23. The rotating body 3 is composed of a plate-shaped cover 31 and a shroud 33 in which a multipolar magnetized disk-shaped driven magnet 32 is embedded. As shown in FIG. 2, a plurality of (six in the illustrated example) tubular blood passages 34 are formed radially from near the center of the rotating body 3. When the cover 31 and the shroud 33 are formed by different members, a groove serving as a blood passage 34 is formed in the shroud 33, and an upper open surface of the groove is shielded by the cover 31 to form a closed tubular blood passage. 34 are formed.

The constituent materials of the housing 2, the cover 31, and the shroud 33 include, for example, hard polyvinyl chloride, polyethylene, polypropylene, polystyrene, polycarbonate, acrylic resin, acrylic resin such as polymethyl methacrylate (PMMA), polyethylene Various hard resins such as polyester such as terephthalate (PET) and polybutylene terephthalate (PBT), polysulfone, and polyarylate are exemplified. Among these, polycarbonate and acrylic resin are particularly preferred in that they are nontoxic, have excellent compatibility with blood, are transparent, and have excellent moldability.

The thickness of the cover 31 is not particularly limited, but is preferably about 0.5 to 3 mm, preferably about 1 to 2 mm.

The cover 31 has a circular opening 35 for guiding the blood introduced into the housing 2 from the blood inlet 21 to the blood passage 34. That is, the blood introduced into the housing 2 from the blood introduction port 21 is distributed and introduced into each blood passage 34 through the opening 35, and a centrifugal force is applied by the rotation of the rotating body 3, and the blood flows through each blood passage 34. The blood flowing toward the outer periphery of the rotator 3 and further flowing out of the blood passage passes through the space 7 between the inner peripheral surface of the housing 2 and the outer peripheral surface of the rotator 3 and is discharged from the blood outlet 22. Things.

Each blood passage 34 has a linear shape from the vicinity of the center of the rotating body 3 to the outer periphery. The cross section of the blood passage 34 has a rectangular shape, and its cross-sectional area (cross-sectional area) is substantially constant along the blood flow direction in the blood passage. Thereby, the blood flow path 34
The flow velocity of blood flowing in the blood becomes almost constant, and as a result, eddy flow is less likely to occur, and the occurrence of flow disturbance is suppressed.
(Represented by hemolysis) is suppressed. In particular, since the blood passage 34 has a linear shape, the priming amount can be further reduced without lowering the pump characteristics.

Here, the expression that the cross-sectional area of the blood passage 34 is substantially constant means not only that the cross-sectional area of the blood passage 34 is completely constant, but also that, for example, a slight taper is formed on the inner surface of the blood passage 34. As a result, the cross-sectional area of the blood passage 34 slightly increases, but the concept also includes a state in which the flow velocity of the blood flowing in the blood passage 34 hardly changes.

When the rotating body 3 is manufactured by integrally molding the cover 31 and the shroud 33, the inner surface of the blood passage 34 is formed as a taper for forming the blood passage 34 by 1 °.
Although a slight gradient may be formed, its performance is equivalent to the case where the cross-sectional area of the blood passage 34 is constant from the inlet to the outlet of the blood passage. If the rotating body 3 is formed as an integral product as described above, there is an advantage that the inner surface of the blood passage 34 has no seam and a thrombus hardly occurs.

The cross-sectional shape of the blood passage 34 is not limited to a square, but may be a circle, an ellipse,
The shape may be a semicircle, a semiellipse, or a polygon other than a square.

Although the number of blood passages 34 formed in the rotating body 3 is not particularly limited, it is usually preferably about 2 to 12, particularly about 4 to 8. Further, the cross-sectional area of one blood passage 34 is not particularly limited, but usually,
10 to 100 mm ² approximately, particularly preferable to be 20 to 50 mm ² approximately. With the number and the cross-sectional area as described above, it is possible to achieve both a reduction in the amount of priming and an improvement in pump efficiency.

In the present invention, the blood passage 34 may be formed such that its cross-sectional area continuously decreases along the blood flow direction in the blood passage. As a result, the blood in the blood passage becomes an accelerated flow as the distance from the center of the rotating body 3 increases, and as in the case described above, the occurrence of turbulence in the flow is suppressed, and the destruction and functional deterioration of the cells in the blood are suppressed.

In this case, the reduction rate of the cross-sectional area of the blood passage 34 (the ratio of the cross-sectional area of the passage outlet end to the cross-sectional area of the passage entrance end) is not particularly limited.
It is preferably about 0%, particularly preferably about 50 to 80%.

The cross-sectional area of the blood passage 34 can be reduced by gradually reducing the height and / or width of the blood passage 34 having a rectangular cross section. In the case of an elliptical, semi-circular or semi-elliptical blood passage 34, this is made possible by gradually reducing its diameter.

In the present invention, each blood passage 34 is not limited to a linear shape as shown in the figure, but may be curved with an appropriate curvature. in this case,
Preferably, it is curved so as to protrude in the rotation direction of the rotating body 3.

The blood passage 34 has a center line (a center line in the blood flow direction) and a center axis of the rotating body 3 (the protrusion 36).
(Below in the figure) is about 75 to 90 °, especially 7 °.
Preferably, it is formed to be 7 to 83 ° (approximately 80 ° in the illustrated example). With such a configuration, when blood is filled into the chamber 23, air bubbles existing in the blood in the blood passage 34 float up to near the opening 35 along the inner surface of the cover 31 and are removed from the blood inlet 21. Can be easily performed. It is preferable that the angle of the blood passage 34 with respect to the center axis of the rotating body 3 is equal in all the blood passages 34.

At the center of rotation of the shroud 33 and at a position facing the opening 35, a conical projection 36 projecting toward the blood inlet 21 is formed. Blood inlet 2
The blood introduced from 1 and passed through the opening 35 is radially diverted by the protrusion 36. Such a protrusion 3
By providing 6, the blood that has passed through the opening 35 can be uniformly and efficiently distributed to each blood passage 34,
Pump efficiency is improved.

As shown in FIG. 3, the angle θ ₁ between the outer peripheral surface of the projection 36 and the central axis of the rotating body 3 is 10 to 10.
It is preferably about 80 °, especially about 30-60 °. If the angle theta ₁ is at least 80 °, the change in the flow direction of the blood inlet port 21 is too large. Also, the angle θ ₁
Is less than 10 °, the change in the flow direction at the entrance of the blood passage 34 becomes too large.

The diameter D ₁ (maximum diameter) of the bottom of the projection 36 is preferably about 25 to 100%, particularly about 50 to 80%, of the diameter D ₂ of the opening 35. The height H is preferably about 1 to 20 mm, particularly preferably about 2 to 10 mm.

The position of the top of the projection 36 is below the opening 35 in FIG. 1, inside the opening 35, or above the opening 35 in FIG. 1 (particularly, as shown in FIG.
1).

The shape of the projection 36 is not limited to a conical shape as shown in the figure, but may be another shape of a rotating body whose flat cross-sectional area gradually increases toward the bottom surface, such as a shell shape or a hemisphere. , And is preferably provided concentrically with the rotating body 3.

The rotating body 3 is rotatably supported in the housing 2 by the bearing 4. The bearing part 4 includes a shaft 41 fixed to the bottom of the housing 2 and a bearing 42 installed in the shroud 33.
It is composed of

The bearing 42 is buried in the center of the shroud 33, and the shaft 41 is fitted in the bore. As the bearing 42, for example, a ball bearing or a roller bearing is suitably used. In addition, a sliding bearing or the like may be used.

The ring-shaped sealing member 5 is fixed to the bottom of the shroud 33 and to the outer periphery of the shaft 41. As the rotating body 3 rotates, the sealing member 5 shown in FIG.
The lip portion 51 at the middle and lower ends slides while being in close contact with the outer peripheral surface of the shaft 41, so that the inside of the chamber 23 and the inside of the shroud 33 are shut off.

As a constituent material of the seal member 5, for example, a soft resin such as polybutadiene, polyisoprene, or polyisobutylene, or an elastomer such as silicone rubber, natural rubber, fluorine rubber, or polyurethane is preferably used. Among them, silicone rubber, fluorine rubber, natural rubber, polyurethane elastomer are particularly preferable in that generation of frictional heat due to sliding with the shaft 41 is smaller and local denaturation and coagulation of blood can be effectively prevented. Is preferred.

Such a sealing mechanism is not limited to a lip seal as shown in the figure, but may be applied to a face seal using an elastic body and a counter face, a mechanical seal using a sliding member and a counter face, or the like. Good.

The structure of the bearing portion 4 is not limited to the illustrated one. For example, the shaft 41 is fixed to the shroud 33 and the bearing 42 is installed at the bottom of the housing 2.
A structure in which the bearing 42 is shut off from the inside of the chamber 23 by a predetermined sealing mechanism may be used.

In the present invention, a guide surface (first guide surface) 8 is formed on the inner peripheral surface of the opening 35 along the inclined outer peripheral surface 361 of the projection 36. A guide surface (second guide surface) 9 formed along the inclined outer peripheral surface 361 of the protrusion 36 at a connection portion between the upper inner surface of the housing 2 in FIG. 1 and the inner surface of the blood inlet 21 in FIG. Are formed. In the case shown,
The guide surfaces 8 and 9 are formed as inclined surfaces that are inclined substantially parallel to the outer peripheral surface 361 of the protrusion 36. In addition, the guide surfaces 8 and 9 can be recognized as a chamfered surface obtained by chamfering a connecting portion between the blood inlet 21 and the inner surface of the housing 2 and a corner formed at a lower edge of the opening 35.

The guide surfaces 8 and 9 and the protrusion 36
A conical annular expanding flow path 10 expanding toward the bottom is formed between the outer peripheral surface 361 and the outer peripheral surface 361 of the developing apparatus. The blood introduced from the blood introduction port 21 is distributed to the respective blood passages 34 through the expansion channel 10. In the expansion channel 10, the blood flow is adjusted smoothly and uniformly. In addition, the disturbance of the blood flow when the blood flows into the blood flow is reduced, thereby suppressing the hemolysis.

The guide surfaces 8 and 9 are formed on the outer peripheral surface 36.
Not only in the case of being parallel to 1 but also in the case where the entire inclination direction is the same as the outer peripheral surface 361. For example, the inclination of the tangent in the center line direction of the guide surfaces 8 and 9 may be a curved surface that approaches horizontally in the blood flow direction (for example, the shape in a side sectional view may be an arc shape). ).

As shown in the figure, the guide surface 8 is desirably located within the extension surface of the guide surface 9 or on the outer peripheral side of the rotating body with respect to the extension surface. By adopting such a position, disturbance of the blood flow is reduced, and the amount of inflowing blood flowing into the space 6 can be suppressed.

The angle θ ₂ between the guide surface 9 and the central axis of the rotating body 3 is about 10 to 80 °, preferably 3 °.
The angle θ3 between the guide surface 8 and the central axis of the rotating body ₃ is preferably about 10 to 80 °, and more preferably about 30 to 60 °. The size of the theta _2, and theta ₃ is the same as the size of the angle theta ₁ of the outer peripheral surface of the projecting portion 36 and the center axis of the rotary body 3 also, may be different, theta ₂ and theta ₃ is it is preferred that each theta ₁ or more. Further, the magnitudes of θ ₂ and θ ₃ are
Although they may be the same or different, it is preferable that θ ₃ ≧ θ ₂ .

In the vicinity of the blood introduction port 21 and the opening 35, the pressure is low, so that bubbles are easily generated. In particular, when air bubbles flowing from the upstream side of the blood pump 1 stay near the opening 35, the air bubbles become nuclei and the generation of air bubbles due to a pressure drop is promoted. As a result, cavitation is generated, and a sudden decrease in the pump head and cavitation cause more than normal hemolysis.

However, as described above, by providing the expanding flow path 10 by the projections 36 and the guide surfaces 8 and 9, the flow direction of the blood flow is smoothly changed, and the stagnation of the inflowing bubbles is prevented. As a result, the air handling characteristics are improved, and as a result, nucleated air bubbles do not stay, and furthermore, the turbulence of the flowing blood is significantly reduced, so that the occurrence of cavitation when blood flows into the opening 35 is reduced. Restrained,
It is possible to reduce a sudden drop in head and an increase in hemolysis.

When driving such a blood pump 1, external driving means (not shown) is provided at the bottom of the housing 2.
Attach. This external driving means includes, for example, a motor,
A multi-polar magnetized drive magnet fixed coaxially to the axis of the rotor, and the drive magnet faces a driven magnet 32 incorporated in the blood pump 1 so that they mutually attract each other. Attached to. When the driving magnet is rotated by the rotation of the motor, the rotating force is transmitted to the driven magnet 32 in a non-contact manner, and the rotating body 3 rotates counterclockwise in FIG. As a result, the blood introduced into the housing 2 from the blood introduction port 21 is distributed and introduced into the respective blood passages 34 through the openings 35, and further, a centrifugal force is applied to the blood to pass through the inside of each blood passage 34 to the rotating body 3. After flowing toward the outer circumference and flowing out of the blood passage, it is discharged from the blood outlet 22 through the space 7.

It should be noted that the external driving means is constituted only by a flat type stator coil, and a flat type brushless motor structure in which the driven magnet 32 is directly driven by this stator coil is also possible.

Further, torque is not transmitted to the rotating body 3 by suction of the driving magnet and the driven magnet 32, and the rotating shaft of the rotating body 3 and the driving shaft of the external driving means are connected by a detachable coupling mechanism. The configuration may be as follows.

Also, without using such external driving means,
The blood pump 1 may be configured to include a driving unit (motor). In this case, a structure in which the rotation axis of the driving means and the rotation axis of the rotating body 3 are directly connected can be adopted.

Although the use of the blood pump of the present invention is not particularly limited, it has the above-described functions and effects.
For example, respiratory assistance (ECM) during heart surgery or respiratory failure
O), preferably used in extracorporeal blood circulation circuits such as emergency assisted circulation systems (EBS), left heart bypass (LHB), and ventricular assist devices (VAD).

Although the blood pump of the present invention has been described with reference to the illustrated configuration example, the present invention is not limited to this. The blood pump of the present invention can be applied to, for example, the sending of a body fluid (biological fluid) other than blood, such as plasma, or the sending of a liquid containing a substance that is easily denatured by heat. The same effect can be obtained.

[0059]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described. Example 1 A blood pump having the structure shown in FIGS. 1 to 3 was manufactured. The conditions of each part are as follows.

<Housing> Material: Acrylic resin Radius of chamber: 42 mm Priming amount: 47 ml Inner diameter of blood inlet: 8 mm Inner diameter of blood outlet: 8 mm Angle θ between guide surface and central axis of rotating body ₂ : 45 °

[0061] <rotator> Material: polycarbonate resin, radius: 39 mm, cover the opening diameter D _2: thickness of 19 mm - Cover: angle of 2 mm, the guide surface and the center axis of the rotating body theta _3: 45 °・ Number of blood passages: 6 (arranged at equal angles) ・ Cross-sectional area of blood passages: 32 mm ² (constant over the entire length of the passages) ・ Angle between the center line of the blood passages and the central axis of the rotating body: 8
0 ° · Angle θ ₁ between the outer peripheral surface of the projection and the center axis of the rotating body:
45 ° ・ Protrusion bottom diameter D ₁ : 15mm ・ Follower magnet: Ring-shaped 6-pole magnetized ferrite magnet ・ Follower magnet dimensions: outer diameter 70mm, inner diameter 32mm, thickness 8mm

<External drive> Motor: brushless DC motor (90
w) ・ Driving magnet: Ring-shaped 6-pole magnetized ferrite magnet ・ Driving magnet dimensions: Outer diameter 70 mm, inner diameter 32 mm, thickness 10 mm ・ Installation interval between driving magnet and driven magnet: 8.5
mm

Comparative Example A blood pump (Biomedi) prepared based on Japanese Patent Publication No. 57-23114.
cus, model BP-80).

[Measurement of Pump Rotation Speed] The hematocrit value of each blood pump of Example 1 and Comparative Example was 38%.
1800 ml of blood, discharge pressure 400 mmHg, flow rate 3
When operated so as to satisfy the condition of L / min, the rotation speed at the operating point was 2150 rpm for the blood pump of Example 1, and
The blood pump of the comparative example was at 2900 rpm. Thus, it was confirmed that the blood pump of Example 1 of the present invention could obtain the same discharge pressure at a lower rotation speed than the blood pump of Comparative Example.

[Measurement of Hemolysis Rate] For each of the blood pumps of Example 1 and Comparative Example, 1800 ml of blood having a hematocrit value of 38% was used, discharge pressure was 400 mmHg, and flow rate was 3 L / min.
Were operated under the following conditions, and the time-dependent change in the hemolysis rate (free hemoglobin concentration in blood) was examined. As a result, each blood pump of Example 1 of the present invention has a lower hemolysis rate (hemolysis amount) than the blood pump of the comparative example, and particularly, a long time (180 minutes or more).
Even when the pump was operated, it was found that the increase in the hemolysis rate (hemolysis amount) was small.

[Measurement of Pump Characteristics] Using the blood pumps of Example 1 and Comparative Example, a glycerin solution having a viscosity of 4 cP was fed, and the discharge pressure (head (mmHg)) of the pump was measured. This measurement was performed at a rotation speed of 2000 rpm.
This was performed by changing the pump flow rate (L / min). The results are shown in Table 1 below.

[0067]

[Table 1]

As shown in Table 1 above, Example 1 of the present invention
It can be understood that the blood pump of the present invention exhibits excellent pump characteristics as compared with the blood pump of the comparative example.

[Evaluation of Air Handling Characteristics] Example 1
And each blood pump of the comparative example, using physiological saline,
The operation was performed so that the flow rate was 4 L / min and the pressure of the blood inlet was -200 mmHg, and 0.1 cc of air was injected from the upstream of the pump. As a result, in the comparative example, cavitation occurs,
When the air in the pump is collected after 20 minutes, it is 0.2 to 0.2.
It increased to about 6cc.

In the first embodiment, almost all of the injected air bubbles are discharged, only a part of them stays in the opening for about 2 minutes.
No cavitation was observed, and excellent air handling characteristics were exhibited.

[0071]

As described above, according to the blood pump of the present invention, it is possible to suppress the destruction and functional deterioration of the cells in the blood to be conveyed without increasing the amount of priming, to achieve a lower rotation and to reduce the cavitation. Low generation and excellent pump characteristics.

[Brief description of the drawings]

FIG. 1 is a sectional side view showing a configuration example of a blood pump of the present invention.

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 is an enlarged sectional view of a protrusion and an opening in FIG. 1;

[Explanation of symbols]

 Reference Signs List 1 blood pump 2 housing 21 blood inlet 22 blood outlet 23 chamber 24 inner peripheral surface of housing 25 edge 3 rotator 31 cover 32 driven magnet 33 shroud 34 blood passage 35 opening 36 protrusion 361 outer peripheral surface 362 top 4 bearing 41 Shaft 42 Bearing 5 Seal member 51 Lip part 6 Space 7 Space 8 Guide surface 9 Guide surface 10 Expanding flow path

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-71490 (JP, A) JP-A-4-212370 (JP, A) JP-A-48-82403 (JP, A) 6837 (JP, U) Japanese Utility Model Showa 58-87990 (JP, U) Japanese Utility Model Utility Model Showa 52-67603 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) A61M 1/10 530

Claims (6)

(57) [Claims] 1. A substantially circular chamber is formed therein, a blood outlet communicating with the chamber, a housing having a blood inlet formed in the center of the chamber and communicating with the chamber, and a housing having a blood inlet formed in the center of the chamber. An opening formed opposite the blood inlet,
A blood pump having a plurality of blood passages arranged radially from the opening and housed concentrically in the chamber and a bearing for rotatably supporting the rotator in the chamber; A projection protruding toward the blood introduction port is provided at the center of the rotating body, and a first guide surface facing the outer circumference of the projection is provided on an inner peripheral surface of the opening. Further, a second guide surface facing the outer peripheral surface of the protrusion is provided at a connection portion between the blood inlet and the inner surface of the housing, and the outer peripheral surface of the protrusion and the first and second guide surfaces are provided. An expanded flow path for distributing the blood flow from the blood inlet to each blood passage is formed between the first guide surface and the second guide surface. A blood pump located outside the blood pump. 2. The apparatus according to claim 1, wherein an angle formed between the first guide surface and a center axis of the rotating body is equal to or larger than an angle formed between the second guide surface and a center axis of the rotating body. Blood pump. 3. The blood passage according to claim 1, wherein the blood passage is formed so as to have a substantially constant or continuously decreasing cross-sectional area along a flow direction of blood in the blood passage. Blood pump. 4. The blood pump according to claim 1, wherein said blood passage is tubular. 5. The blood pump according to claim 1, wherein the blood passage has a linear shape. 6. The blood pump according to claim 1, wherein said blood passage is formed such that a center line thereof forms an angle of 75 to 90 ° with a center axis of said rotating body.