JPH07222940A - Rotor for centrifugal separator - Google Patents

Abstract

PURPOSE:To prevent stress from converging into corner parts and extend the life of a bucket by forming a through hole in a wall part of a bucket supporting and receiving part parallel to an axial direction of an arm pin. CONSTITUTION:A bucket is fixed in a rotor of a centrifugal separator which separates blood in a blood bag. A through hole 53 is formed in the wall face of a supporting and receiving part 51 of the bucket 5. In this way, the corner parts are eliminated from the supporting and receiving part 51, and parts where stress converges and stress is very high are thus eliminated. As a result, since other parts where the stress value is low can receive the centrifugal load, the stress is lessened and cracking scarcely occurs. Consequently, the bucket is prevented from being broken and its life is prolonged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotor for a centrifuge for suspending a bucket containing blood or the like on a rotor body for centrifugal separation.

[0002]

2. Description of the Related Art In the past, when performing blood transfusion, there were many "whole blood transfusions" in which blood collected from a blood donor was directly transfused, but nowadays, "component transfusion" is performed in which only certain components of necessary blood are transfused to patients. Is the mainstream. In this case, for the blood component separation, a blood component separating centrifuge capable of separating blood components by directly setting a blood bag containing blood collected from a donor into a centrifuge is used.

A centrifugal separator of this type is shown in FIGS. 9 and 1.
It will be described using 0.

First, as shown in FIG. 9, a centrifuge 10 of this type includes a motor 11 as a drive source and a motor 1 of this type.
A rotor 1 that is rotated by 1 and is provided with a centrifugal force is provided. The rotor 1 is provided with a rotor body 2 which is rotated by a motor 11 similarly to the rotor 1, and a bucket 5 is suspended in the rotor body 2 in a detachable state, that is, suspended. The rotor body 2 may be, for example, No. 56-42346 or No.
It has a shape as shown in No. -12452 and is provided with an arm pin 3 for supporting the bucket 5. Further, since the bucket 5 is swingably supported by the rotor body 2, the bucket 5 has a support receiving portion 51 that engages with the arm pin 3.

In order to perform the above-mentioned centrifugation on the centrifuge 10 constructed as described above, first, as shown in FIG. 10, a blood bag 7 containing blood collected from a donor is placed in a cup 6. The cup 6 into the motor 1
It is loaded in a bottomed hollow bucket 5 suspended from a rotor body 2 rotated by 1. When the motor 11 of the centrifuge 10 is driven in this state, as shown in FIG. 9, the bucket 5 swings horizontally with the arm pin 3 as a base point by the centrifugal force, and the blood loaded in the bucket 5 is bucketed. It is subjected to centrifugal force in that direction and is centrifuged. When the predetermined centrifugal separation is performed, the motor 11 is gradually decelerated to weaken the centrifugal force, swing the bucket 5 to the initial position, and finally stop the motor 11. After that, the blood bag 7 containing the centrifuged blood,
First, the bucket 5 is taken out in the reverse order of loading, and the work is completed.

The shape of the opening of the conventional bucket 5 is shown in FIG.
The bucket 5a having a circular opening as shown in Fig. 1 is the most common, but recently, the shape of the bucket opening shown in Fig. 12 as shown in Japanese Patent Application No. 5-9219 is long. A circular bucket 5b, a bucket 5c shown in FIG. 13 having an elliptical opening, and a composite R-shaped bucket 5d shown in FIG. 14 in which two or more R-shaped openings are combined have begun to be used. As described in Japanese Patent Application No. 5-9219, these new buckets have begun to be used. Until now, a blood bag has a parent bag containing whole blood collected and a whole blood bag. A triple bag constituted by connecting three bags, a child bag containing a plasma component separated by centrifugation and a child bag further containing platelets was mainly used, but recently a bag commonly called a MAP bag has been used. This is because the blood bag with MAP liquid (also called ACD-A quadrapple bag), which is configured by connecting four pieces, has started to be used. By the way, the purpose of MAP bag is to reduce the contamination of blood products produced by separating blood with white blood cells, especially to remove lymphocytes to reduce infection by transfusion, and to enable long-term storage of red blood cell products. is there. (The conventional blood bag had a storage period of 21 days, but a MAP bag can be stored for 42 days.) However, compared to the conventional blood bag, it contains MAP solution, and the bag of the bag is The increase in the number by one increases the volume, and there arises a problem that the conventional bucket 5a and the circular cup do not allow the opening to fit tightly depending on the amount of collected blood. To solve this problem, Japanese Patent Application No. 5
The bucket 5b having an elliptical opening as described in -9219, the bucket 5 having an elliptical opening, and the bucket 5d having a complex R-shaped opening are used together with a circular bucket. Has become.

[0007]

In the above centrifugal separation, a user strongly desires a centrifugal separator capable of completing a predetermined centrifugal separation in a shorter centrifugation time. For that purpose, it is most effective to increase the centrifugal force applied to blood. However, increasing the centrifugal force applied to blood means increasing the centrifugal force applied to the bucket as a result. As shown in FIGS. 6 to 8,
When a high centrifugal force is applied to the bucket 5, as shown in FIG. 6, stress concentrates on the corner 52 of the support receiving portion 51 of the bucket 5 that engages with the arm pin 3 provided on the rotor body 2, The possibility that a defect such as a crack 59, that is, a crack 59, occurs in the portion indicated by is increased. These buckets have a low specific gravity to rotate at higher speeds,
Aluminum alloys of duralumin series, which have high strength and relatively low cost, are often used, but once this crack occurs, stress corrosion cracking easily progresses, so that the bucket eventually breaks and high speed is achieved. New problems such as unbearable rotation and short life have occurred.

Further, in order to use the above-mentioned MAP bag, it is necessary to increase the inner volume as compared with the conventional bucket, and to increase the inner diameter of the opening, or to make the opening oval or elliptic or compound R. By making the shape, the outer shape of the opening also becomes large, the total mass of the bucket increases, and the centrifugal load applied to the support receiving portion increases. In addition, by making the opening into an elliptical shape or a compound R shape, when the opening has a circular shape, the support receiving portion has a curved surface, whereas the support receiving portion has a flat surface portion to reduce rigidity and rotate. The deformation of the bucket becomes large at this time, and the support receiving part fixed by the rotor pin receives a compressive load in the horizontal direction during rotation, but the side wall of the support receiving part is more easily deformed than the support receiving part, so the rigidity is The lowering makes it easier to deform toward the center of the bucket opening. In particular, these buckets are detachable from the rotor body 2 so that they can be washed to handle blood, and the support receiving portion of the bucket is formed into a concave shape so that the arm pin can be inserted thereinto. There is a support receiving portion corner portion 52 at the tangent portion between the support receiving portion side wall 50 and the support receiving portion side wall 50, and when a load is applied to the support receiving portion by centrifugal force, the corner portion of the support receiving portion receives bending moment and stress concentrates. I will end up. As a result,
As shown in, cracks occur in the corners of the support receiving portion. In such a case as well, similarly to the above, new problems occur such that the bucket finally breaks, cannot withstand high speed rotation, and has a short life.

Further, in the conventional bucket, when the rotor rotates, the opening swings horizontally, but a lubricant is applied to the bucket support receiving portion and the arm pin portion of the rotor body so that the swing is always smooth. Although it is applied, the lubricant may be deposited on the end surface of the arm pin and the wall surface of the bucket support receiving portion by repeated application, which may make it difficult to swing. In such a state, when the rotor stops, the bucket does not return to the smooth direction in the process of gradually decelerating the rotor, and the boundary surface of the separated blood components is disturbed, resulting in poor separation. Sometimes.

An object of the present invention is to solve the above problems and provide a long-life bucket that can rotate at high speed.

[0011]

As shown in FIG. 6, the stress of the bucket during rotation exerts a load on the entire bucket due to centrifugal force. As described in the problems to be solved by the invention, the stress of the bucket is particularly large. Stress concentrates on the corner portion 52 of the support receiving portion 51. Further, in the case of an oval bucket or a compound R-shaped bucket, the concentration is particularly remarkable due to the bending moment due to the deformation of the bucket.

From the above, the countermeasure for the above problem is achieved by forming the through hole 53 in the wall surface of the support receiving portion of the bucket where the stress is concentrated to eliminate the corner portion which causes the stress concentration.

[0013]

The bucket configured as described above has a through-hole in the wall surface of the support receiving portion, and thus the cross-sectional area of the support receiving portion becomes small, and at first glance it seems that the strength is weak, but stress concentration at the corners Is eliminated, and the centrifugal load can be received in other parts with low stress values, stress is reduced, cracks do not occur, and the life is extended.

[0014]

EXAMPLES Examples will be described with reference to FIGS. 1 to 5.

FIG. 1 is a perspective view of a bucket of a centrifuge rotor according to a first embodiment of the present invention. As shown in FIG. 5, a through hole 53 is provided in the side wall 50 of the bucket support receiving portion 51 of the support receiving portion 51 of the bucket 5 to eliminate the corner 52 of the support receiving portion 51, resulting in high stress concentration and high stress. It is a structure with no parts. Other configurations are the same as those of the conventional bucket.

As described above, by adopting a structure in which there is no portion where the stress concentration is high, the structure is such that the crack 59 shown in FIG. In addition, since there is a through hole 53 in the wall surface 50 of the support receiving portion 51, the cross-sectional area of the support receiving portion 51 becomes small.
Although the strength seems to be weak, there is no problem in strength because the stress concentration at the corners disappears and the centrifugal load is applied to the other parts where the stress value is low.

The effect of the through hole 53 was confirmed by a fatigue test in which a centrifugal load was repeatedly applied to the bucket 5 with an actual centrifuge. A bucket 5b having an oval opening as shown in FIG. 11 was used in the test, and a centrifugal load of 6.07 ton generated at the maximum operating speed of the centrifuge used in the test was used. When there is no through hole 53, cracks occur after about 46,000 repetitions and about 17
Whereas, when the through hole 53 was provided, the fracture occurred after 2,000 cycles, but the result was that cracking occurred after about 114,600 cycles and fracture at about 210,000 cycles. From this, it was confirmed that the life can be extended by providing the through hole 53.

In this test, a bucket having an oval opening was used. However, the applicant also carried out another test on a bucket 5a having a circular opening as shown in FIG. Centrifugal load uses the same 6.07 ton as the above test,
When there is no through hole 53, the number of repetitions is about 119000
While there is a crack in the corner of the support receiving part at the time,
When the through hole 53 was provided, it was obtained as a result that the crack did not occur even after repeating 200,000 times.

Further, in order to make the swing smooth, a quick-drying lubricant such as Teflon coat is often used for the support receiving portion 51, but by providing the through hole 51, the rotor body 2 is provided with a hole. A lubricant is not deposited between the end surface of the muping pin 3 and the side wall 50 of the support receiving portion 51, and swing failure can be prevented.

However, in the case of a normal rotor, the arm pin 3 shown in FIG. 10 is a circular shaft, and when the through hole 53 is circular as shown in FIG. Since 51 has a concave shape, the width of the recess for hooking the bucket 5 is almost the same as the outer diameter of the arm pin 3, and the arm pin 3 enters the through hole 53 of the bucket 5 to move the bucket 5. There may be a problem that the bucket 5 becomes difficult to remove.

To improve this problem, the bucket 5
This can be dealt with by making the size of the through hole 53 of (1) smaller than the size of the arm pin 3. With such a structure, the arm pin 3 does not enter the through hole, and the bucket 5 can be easily attached and detached similarly to the conventional product without being caught, and the above problems can be solved.

Making the size of the through hole 53 smaller than that of the arm pin 3 means that the hole diameter of the through hole 53 is made smaller than that of the arm pin 3 as well.
Through holes 53, 53a, 5 are formed by forming the through holes in a semicircular shape or a partial circular shape as shown by 53a in FIG. 2 or by making the through holes into a polygonal shape as shown in 53b in FIG.
It also includes preventing the arm pin 3 from getting into 3b. In this way, by making the shape of the through hole 53 into a shape in which the arm pin 3 cannot be inserted, the attachment and detachment of the bucket 5 can be facilitated as in the conventional product, and the above problems can be solved.

In order to prevent the arm pin 3 from being inserted into the through hole 53, in addition to defining the sizes of the through hole 53 and the arm pin 3 as described above, there is a method of closing the through hole with the closing member 60. is there. If the through hole 53 is blocked by the closing member 60, the above-mentioned problem can be solved by whatever relationship between the size of the through hole 53 and the size of the arm pin 3. In addition, it is preferable that the closing member 60 is made of an elastic body such as rubber or resin in order to facilitate its removal.

[0024]

According to the present invention, by providing the through hole in the bucket, it is possible to eliminate the portion where the stress of the bucket is concentrated, so that it is possible to withstand a high centrifugal force without lowering the strength of the bucket itself. , Can provide long life buckets.

[Brief description of drawings]

FIG. 1 is a centrifuge roll showing a first embodiment of the present invention.
FIG.

FIG. 2 is a centrifuge roll showing a second embodiment of the present invention.
FIG.

FIG. 3 is a centrifuge roll showing a third embodiment of the present invention.
FIG.

FIG. 4 is a centrifuge roll showing a fourth embodiment of the present invention.
FIG.

FIG. 5 is a cross-sectional view of buckets according to first to third embodiments of the present invention.

6 is a partially enlarged view of FIG. 8 for explaining the stress applied to the bucket when the rotor for the centrifuge rotates.

FIG. 7 is a cross-sectional view showing a cracked portion of a conventional bucket.

FIG. 8 is a sectional view of a conventional bucket.

FIG. 9 is a vertical sectional view showing a schematic configuration of a centrifuge.

FIG. 10 is a perspective view showing how the bucket, cup, and blood bag are attached to the rotor body.

FIG. 11 is a plan view of a bucket having a circular opening shape.

FIG. 12 is a plan view of a bucket having an oval opening shape.

FIG. 13 is a plan view of a bucket having an elliptical opening shape.

FIG. 14 is a plan view of a bucket whose opening shape is a compound R shape.

[Explanation of symbols]

1 is a rotor, 2 is a rotor body, 3 is an arm pin, 5 is a bucket, 5a is a circular bucket, 5b is an oval bucket, 5c is an oval bucket, 5d is a compound R-shaped bucket, 6 is a cup, 7 Is a blood bag, 10 is a centrifuge,
11 is a motor, 50 is a side wall of the support receiving portion, 51 is a support receiving portion,
52 is a corner of the support receiving portion, 53, 53a, 53b, 53c
Is a through hole, 59 is a crack, and 60 is a member for closing the hole.

Claims (9)

[Claims] 1. A rotor body rotatably driven by a motor, an arm pin provided on the rotor body, and a bucket suspended and supported on the rotor body by having a support receiving portion that engages with the arm pin. In the centrifuge rotor, the centrifuge rotor is characterized in that a through hole parallel to the axial direction of the arm pin is provided in a side wall of the support receiving portion. 2. The rotor for a centrifuge according to claim 1, wherein the size of the through hole is the same as or smaller than the size of the arm pin so that the arm pin does not enter the through hole. . 3. The rotor for a centrifuge according to claim 1, wherein the size of the through hole is larger than the size of the arm pin, and the through hole is closed by a closing member. 4. The rotor for a centrifuge according to claim 3, wherein the closing member is made of an elastic body. 5. The bucket is detached from the rotor body by forming a support receiving portion provided on the bucket that engages with the arm pin provided on the rotor body so that a bottom surface side of the bucket is opened. It is configured to be possible.
A rotor for a centrifuge according to any one of 1. 6. The rotor for a centrifugal separator according to claim 1, wherein the shape of the opening of the bucket is circular. 7. The rotor for a centrifuge according to claim 1, wherein the opening of the bucket has an oval shape. 8. The centrifuge rotor according to claim 1, wherein the opening of the bucket has an elliptical shape. 9. The rotor for a centrifugal separator according to claim 1, wherein the shape of the opening of the bucket is a complex R shape.