JP2016174826A - Centrifugal separator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a centrifugal separator capable of effectively preventing an occurrence of abnormal noise, while holding a desired sealing performance in rotation of a rotor.SOLUTION: A centrifugal bowl 10 (a centrifugal separator) comprises: a stator 12 including an inflow port 18a and an outflow port 18b of a blood and blood components; a rotor 14 rotatably provided with respect to the stator 12; and a seal mechanism 16 having an annular rotary sliding surface 82 for the stator 12 and the rotor 14. The width W in the radial direction of the rotary sliding surface 82 is set to 1370-1530 μm.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a centrifuge.

  When collecting blood, for the purpose of effective use of blood and reduction of burden on blood donors, blood sample is separated into multiple blood components, and only necessary components (eg, platelets) are collected. Ingredients are collected to return the components to the blood donor. For component blood collection, a blood component separation device equipped with a centrifuge is used.

  A centrifugal bowl type centrifuge used for collecting blood components generally includes a stator provided with an inlet and an outlet for blood or blood components, and a rotor provided rotatably with respect to the stator. Further, the centrifuge is provided with a sealing mechanism that maintains the sealing performance with respect to the stator when the rotor rotates. The seal mechanism has a stator side ring installed on the stator side and a rotor side ring installed on the rotor side and in contact with the stator side ring. When the rotor rotates, the stator side ring and the rotor side ring rotate. Sliding (see, for example, Patent Document 1 below).

International Publication No. 2013/136944 Pamphlet

  By the way, in the conventional centrifuge used for component blood collection, when the rotor rotates, the stator-side ring and the rotor-side ring may generate noise due to rotational sliding. When abnormal noise is generated from the centrifuge, the use of the centrifuge may be stopped. Further, in the centrifuge, when the sealing performance on the rotating sliding surface is low, blood leakage may occur from the rotating sliding surface.

  For this reason, Patent Document 1 adopts a configuration in which the rotational sliding portion between the stator and the rotor is pressed with a predetermined pressing force, thereby preventing the generation of abnormal noise during the rotation of the rotor. However, further improvement is desired in order to more reliably prevent the generation of abnormal noise. Further, in Patent Document 1, the main point is to prevent the generation of abnormal noise during the rotation of the rotor, and further improvement has been made with regard to ensuring sealing performance to prevent blood leakage from the rotating sliding surface. Is desired.

  The present invention has been made in consideration of such problems, and provides a centrifuge capable of effectively preventing the generation of abnormal noise while maintaining a desired sealing property during rotor rotation. Objective.

  In order to achieve the above object, a centrifugal separator according to the present invention includes a stator provided with an inlet and an outlet for blood or blood components, a rotor provided rotatably with respect to the stator, and the stator. And a sealing mechanism having an annular rotational sliding surface with the rotor, wherein a radial width of the rotational sliding surface is set to 1370 to 1530 μm.

  According to the centrifuge configured as described above, the width of the rotational sliding surface between the stator and the rotor is set in an appropriate range, so that a desired sealing property is maintained during rotation of the rotor relative to the stator. However, the generation of abnormal noise can be prevented.

  In the above centrifuge, the centrifuge is configured such that the centrifuge is set in a drive device that drives the centrifuge, and the rotor is in a state where a predetermined pressing force is applied to the rotating sliding surface. Is driven to rotate, and the pressing force may be 500 g or less.

  With this configuration, the pressing force applied to the rotating sliding surface is optimized, so that combined with the effect of optimizing the width of the rotating sliding surface, it is possible to more effectively prevent the generation of noise during the rotation of the rotor. Can do.

  According to the centrifugal separator of the present invention, it is possible to effectively prevent the generation of abnormal noise while maintaining a desired sealing property when the rotor rotates.

It is a half longitudinal cross-sectional view of the centrifuge bowl which concerns on embodiment of this invention. FIG. 2A is an explanatory diagram of the centrifugal bowl driving device with the lid portion opened, and FIG. 2B is an explanatory diagram of the centrifugal bowl driving device with the lid portion closed. It is an enlarged view of a sealing mechanism. It is a graph which shows the result of an airtightness test. It is a graph which shows the result of an allophone test.

  Hereinafter, preferred embodiments of the centrifuge according to the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a semi-longitudinal sectional view of a centrifuge bowl 10 (centrifuge) of the present embodiment. For the sake of explanation, the cross section of the centrifuge bowl 10 is on the right side of the center line, and the appearance of the centrifuge bowl 10 is on the left side of the center line. Is shown.

  The centrifuge bowl 10 includes a stator 12, a rotor 14 that can rotate with respect to the stator 12, and a seal mechanism 16 that has a rotational sliding surface 82 (see FIG. 3) between the stator 12 and the rotor 14.

  The stator 12 has a cylindrical bowl head 18 provided with an inlet 18a and an outlet 18b, a bowl-shaped cover 20 formed on the bowl head 18, and is connected to the bowl head 18 and extends to the rotor 14 side. Inflow pipe 22. The inflow pipe 22 is connected to the inflow port 18a to form an in-pipe flow path 24. The bowl head 18 has a neck portion 26 that is recessed radially inward. The shoulder portion 28 that connects the cover 20 and the neck portion 26 is formed in a shape that draws a round curve so as to go downward in the radial direction.

  On the other hand, the rotor 14 includes a housing 30 having a bell shape and a bottom plate 42 fitted to close the lower end of the other end of the housing 30. The housing 30 includes a side wall 32 that decreases in diameter toward the upper side, and a neck portion 34 that decreases in diameter at the upper end of the side wall 32. The rotor 14 includes an outer shell 36 and an inner shell 38 inside the housing 30, and a blood storage space 39 is formed between the side wall 32 of the housing 30 and the outer shell 36.

  The outer shell 36 is formed in a bell shape. A plurality of support portions 40 are formed at the upper end portion of the outer shell 36 at intervals in the circumferential direction, and the support portions 40 are in contact with the inner peripheral side of the neck portion 34. The inner shell 38 has a funnel shape and is configured to fit with the outer shell 36 at the upper end and the lower end. The inflow pipe 22 is inserted inside the inner shell 38, and the rotor 14 rotates about the center line (rotation axis a) of the inflow pipe 22.

  The bottom plate 42 is a substantially disk-shaped member, and a concave portion for receiving blood flowing down from the in-tube flow path 24 is formed at the center thereof. A bottom channel 44 is formed between the lower surface of the inner shell 38 and the upper surface of the bottom plate 42 so as to extend in a substantially disc shape. The bottom flow path 44 formed between the inner shell 38 and the bottom plate 42 and the in-pipe flow path 24 of the inflow pipe 22 communicate with each other.

  The housing 30, the outer shell 36, and the inner shell 38 are made of a hard material. Examples of the hard material include polycarbonate and polystyrene. In addition, at least the housing 30 of the housing 30, the outer shell 36 and the inner shell 38 is preferably made of a substantially transparent material in order to ensure the visibility of the blood storage space 39.

  The bottom channel 44 communicates with a blood storage space 39 formed by the outer periphery of the outer shell 36 and the inner periphery of the side wall 32. The blood reservoir space 39 has a tapered shape such that its inner diameter gradually decreases as it approaches the outlet 18b side. The volume of the blood storage space 39 is preferably about 50 to 1000 mL, and more preferably about 100 to 300 mL.

  The seal mechanism 16 is a mechanism portion that seals the upper end portion of the rotor 14 in an airtight or liquid tight manner. In this embodiment, the seal mechanism 16 includes an annular stator side ring 50 provided on the stator 12 side, a seal cap 52 whose inner peripheral edge is fixed to the bowl head 18, and a circle provided on the rotor 14 side. And an annular rotor-side ring 54.

  The stator side ring 50 and the rotor side ring 54 are in contact with each other, and rotate and slide on the contact surface when the rotor 14 rotates. The stator side ring 50, the seal cap 52, and the rotor side ring 54 are disposed outside the inflow pipe 22 and inside the cover 20.

  The centrifuge bowl 10 configured as described above is attached to a blood component separation device 60 as shown in FIGS. 2A and 2B and is driven to rotate. The blood component separation device 60 includes a centrifuge bowl driving device 62 in which the centrifuge bowl 10 is disposed.

  The centrifuge bowl drive device 62 includes a centrifuge tank 64 that can accommodate the centrifuge bowl 10, a lid 66 that is provided above the centrifuge tank 64 and is movable with respect to the centrifuge tank 64, and a turn that is rotatable inside the centrifuge tank 64. And a table 68. Both the centrifuge tank 64 and the lid 66 are formed of a transparent member. The turntable 68 is driven to rotate about a vertical axis by a rotation drive source (not shown). The lid 66 is configured to be openable and closable as shown in FIGS. 2A and 2B. 2A shows a state where the lid 66 is opened, and FIG. 2B shows a state where the lid 66 is closed.

  As shown in FIG. 2B, when the lid 66 is closed, the lid 66 abuts against the shoulder portion 28 of the centrifuge bowl 10, and the lid 66 and the neck 26 abut while pushing down the centrifuge bowl 10. When the centrifuge bowl 10 is inserted into the centrifuge tank 64, the bottom plate 42 of the centrifuge bowl 10 contacts the turntable 68. The centrifuge bowl 10 disposed in the centrifuge tank 64 is pressed against the turntable 68 by the shape of the shoulder portion 28 that comes into contact with the lid 66 when the lid 66 is closed. The bottom plate 42 is fixed to the turntable 68 by a fixing mechanism (for example, a vacuum suction mechanism) provided on the turntable 68. Since the turntable 68 is connected to a rotation drive source, the rotor 14 that contacts the turntable 68 can be rotated.

  Referring to FIG. 1, in order to perform blood processing using the centrifuge bowl 10, the rotor 14 is rotated under predetermined centrifugal conditions (rotation speed and rotation time) set in advance. Under this centrifugal condition, the blood separation pattern in the rotor 14 (for example, the number of blood components to be separated) can be set. For example, in the blood storage space 39, the centrifugal conditions can be set so that blood is separated into a plasma layer, a buffy coat layer, and a red blood cell layer from the rotation center side (rotation axis a side) to the outside.

  In blood processing, blood (or a blood component) is introduced from the inlet 18a through a tube (not shown) connected to the inlet 18a, and blood is supplied into the centrifuge bowl 10. The blood that has flowed into the centrifuge bowl 10 flows down the in-tube channel 24 and is carried from the lower end of the in-tube channel 24 to the bottom channel 44. In the bottom channel 44, the blood is carried to the outer diameter side of the rotor 14 by the centrifugal force of the rotating rotor 14, moves to the blood storage space 39, and the blood is centrifuged in a plurality of layers in the blood storage space 39 as described above. Is done. The centrifuged blood sequentially passes from the blood storage space 39 through the shoulder channel 70 between the housing 30 and the outer shell 36, the channel 72 between the bowl head 18 and the inflow pipe 22, and the outlet 18b. Then, it flows out of the centrifuge bowl 10.

  The blood processing in the blood component separation device 60 (FIGS. 2A and 2B) includes a plurality of processing steps, and the rotation speed (rpm) of the rotor 14 varies depending on the type of processing steps and one processing step. The rotor 14 is rotationally driven within the range of 0 to 6000 rpm.

  Next, the configuration of the seal mechanism 16 will be described more specifically.

  As shown in FIG. 3, the stator side ring 50 is attached to the bowl head 18 via a seal cap 52. The stator-side ring 50 is formed with an annular convex portion 80 that comes into contact with the rotor-side ring 54 fixed to the rotor 14 side. The convex portion 80 projects downward from the lower surface of the stator side ring 50. The constituent material of the stator side ring 50 is not particularly limited, but a material excellent in slidability is preferable, and for example, a hard resin such as a phenol resin is suitably used.

  The seal cap 52 is a film-like member made of an elastic body (for example, silicone rubber). The inner peripheral side of the seal cap 52 is fixed to the bowl head 18. The outer peripheral portion of the stator side ring 50 is fixed to the outer peripheral side of the seal cap 52.

  The rotor-side ring 54 is disposed so as to contact the stator-side ring 50 (specifically, the convex portion 80) and is held on the stator 12 side. In the present embodiment, the rotor side ring 54 is fixed to the upper end portion of the neck portion 34. The constituent material of the stator side ring 50 is not particularly limited, but a material excellent in slidability is preferable. For example, ceramics such as alumina is preferably used.

  Further, the seal mechanism 16 has a rotational sliding surface 82 between the stator 12 and the rotor 14. In the case of this embodiment, the rotational sliding surface 82 is a contact surface between the stator side ring 50 and the rotor side ring 54. That is, the rotational sliding surface 82 is a portion where the end surface (lower end surface) in the protruding direction of the convex portion 80 provided on the lower surface of the stator side ring 50 and the upper surface of the rotor side ring 54 are in contact with each other. This is the part that slides when rotating.

  The lower end surface of the convex portion 80 and the upper surface of the rotor side ring 54 lie on a plane orthogonal to the rotation axis a of the rotor 14. Further, the outer peripheral edge and the inner peripheral edge of the lower end surface of the convex portion 80 are formed on concentric circles around the rotation axis a of the rotor 14. Therefore, the rotational sliding surface 82 exists in a plane orthogonal to the rotational axis a of the rotor 14 and has an annular shape in which the radial width W is constant along the circumferential direction.

  The radius of the center position in the radial direction of the rotary sliding surface 82 is set to 12.0 to 17.0 mm, and more preferably set to 13.0 to 15.0 mm.

  As described above, when the centrifuge bowl 10 is installed in the centrifuge bowl drive device 62 and the lid 66 of the centrifuge tank 64 is closed, the centrifuge bowl 10 is turned to the turntable 68 side by the shape of the shoulder portion 28 that contacts the lid 66. Pressed against. At this time, since the rotor 14 is supported by the turntable 68, the stator 12 is slightly pushed down (about several millimeters) in the direction of the turntable 68 (ie, downward). This pushed-down distance is absorbed by the elastic deformation of the seal mechanism 16, particularly the seal cap 52. Thus, when the centrifuge bowl 10 is set in the centrifuge bowl drive device 62, the centrifuge bowl 10 is pressed against the turntable 68, so that a predetermined pressing force is applied to the rotary sliding surface 82.

  In the rotational sliding surface 82, since rotational friction is generated when the rotor 14 is rotated, it is desirable to prevent the generation of noise due to rotational friction. Moreover, since the rotation sliding surface 82 is a mechanism part which bears the sealing function which prevents that the blood leaks from the inside of the centrifuge bowl 10 at the time of rotation of the rotor 14, it is desirable to maintain desired sealing performance. In the present invention, by setting the width W of the rotating sliding surface 82 within a predetermined range, it is possible to achieve both of ensuring a desired sealing property during rotation of the rotor 14 and preventing the generation of abnormal noise. is there.

  Specifically, the width W of the rotary sliding surface 82 is set to 1370 to 1530 μm, and more preferably set to 1380 to 1520 μm.

  FIG. 4 is a graph showing the results of an airtightness test for confirming how the airtightness by the sealing mechanism 16 changes depending on the width W of the rotating sliding surface 82 (hereinafter also referred to as the sliding surface width). is there. In this airtightness test, air is introduced from the inlet 18a into the centrifugal bowl 10 so that the inside of the centrifugal bowl 10 has a predetermined reference pressure (the outlet 18b is sealed), and the inside of the centrifugal bowl 10 after a predetermined time has elapsed. The pressure of was measured.

  Specifically, in this airtightness test, a plurality of sample products (centrifugal bowl 10) were prepared for each sliding surface width. The stator side ring 50 was made of phenol resin, and the rotor side ring 54 was made of ceramics. A sample with a pressure of 95% or less with respect to the reference pressure after the introduction of air is judged as a sample product with low airtightness (hereinafter referred to as a low airtight product), and the different slides tested. The result of deriving the occurrence rate of low airtight products for each of the moving surface widths is the graph of FIG.

  In this airtightness test, sample products of different lots produced on different days were used. Therefore, in FIG. 4, the graph of one lot is indicated by a broken line A and the graph of the other lot is indicated by a broken line B. The dotted line C is a curve obtained by smoothing the broken line A and the broken line B.

  From FIG. 4, it can be seen that when the sliding surface width is smaller than 1370 μm, the occurrence rate of low airtight products is high, and when the sliding surface width is 1370 μm or more, the occurrence rate of low airtight products is low. That is, when the sliding surface width is 1370 μm or more, the airtightness at the rotating sliding surface 82 can be increased. In general, there is a correlation between airtightness and liquid tightness (the higher the airtightness, the higher the liquid tightness). Therefore, by setting the sliding surface width to 1370 μm or more, high liquid tightness at the rotational sliding surface 82 can be obtained, and high sealing performance that can suitably prevent liquid leakage can be secured.

  FIG. 5 is a graph showing the results of an abnormal noise test (vibration acceleration test) for confirming how the occurrence of abnormal noise changes depending on the sliding surface width. In this abnormal noise test, the centrifugal bowl drive device 62 is used to rotate the rotor 14 of the centrifugal bowl 10 (the blood storage space 39 is empty) at a rotation speed of 600 rpm at which abnormal noise is likely to occur, and to evaluate the abnormal noise occurrence state. The vibration state (vibration acceleration) during rotation of the rotor 14 was measured.

  Specifically, the stator side ring 50 was made of phenol resin, and the rotor side ring 54 was made of ceramics. An analyzer that measures vibration acceleration was used as a measuring instrument, and the sensor portion of this analyzer was attached to the cover 20 of the centrifuge bowl 10. The pressing load applied to the rotary sliding surface 82 in a state where the centrifugal bowl 10 is set in the centrifugal bowl driving device 62 is set to be 500 g. A plurality of broken lines D, E, and F in FIG. 5 are a maximum value, an average value, and a minimum value in order from the top. The straight lines DL, EL, and FL shown superimposed on the broken lines D, E, and F are lines obtained by linearizing the broken lines D, E, and F, respectively.

FIG. 5 shows that the vibration acceleration increases as the sliding surface width increases. The lower limit value of the vibration acceleration that may generate an abnormal sound that can be heard by human hearing is 0.115 m / s ² . According to FIG. 5, the vibration acceleration is less than 0.115 m / s ² even when the sliding surface width is 1520 μm (no abnormal noise is generated), but when the sliding surface width is 1575 μm. The maximum value exceeds 0.115 m / s ² (abnormal noise is generated).

When attention is paid to the straight line DL obtained by linearizing the maximum value of the vibration acceleration for each sliding surface width, it intersects with the line G of 0.115 m / s ² at a position slightly smaller than 1540 μm (near 1535 μm). From this, it can be seen that if a sliding surface width of 1530 μm or less is taken into consideration with some allowance, generation of abnormal noise during rotation of the rotor 14 can be prevented.

  As can be seen from the above test results, by setting the width W of the rotating sliding surface 82 in the range of 1370 to 1530 μm in the centrifuge bowl 10, high liquid tightness at the rotating sliding surface 82 can be obtained. It is possible to ensure high sealing performance that can suitably prevent leakage. Further, by setting the width W of the rotary sliding surface 82 in the range of 1380 to 1520 μm, the above effect can be obtained more reliably.

  When the pressing force applied to the rotating sliding surface 82 in the state where the centrifugal bowl 10 is set in the centrifugal bowl driving device 62 (the pressing force applied during the rotation of the rotor 14) exceeds 500 g, the sticking is performed on the rotating sliding surface 82. There is a high possibility that a slip phenomenon will occur, and there is a possibility that the occurrence probability of abnormal noise will increase. The stick-slip phenomenon is self-excited vibration caused by microscopic adhesion between the friction surfaces and repeated sliding. Therefore, the pressing force is preferably set to 500 g or less. As a result, the pressing force applied to the rotary sliding surface 82 is optimized, and combined with the effect of optimizing the width W of the rotary sliding surface 82, the generation of abnormal noise during the rotation of the rotor 14 is more effectively achieved. Can be prevented.

  Further, if the above pressing force is too small, it may be difficult to secure a desired sealing property on the rotary sliding surface 82. For this reason, the pressing force applied to the rotary sliding surface 82 is preferably set to, for example, 300 g or more, and more preferably set to 400 g or more. In addition, it was confirmed by experiment that the desired sealing property on the rotational sliding surface 82 can be secured even when the pressing force is 300 g. The above pressing force can be set, for example, by selecting a constituent material of the seal cap 52 (adjustment of rubber hardness).

  In general, in a centrifuge bowl, the surface roughness of the stator side ring and the rotor side ring constituting the rotary sliding surface is originally smooth and the friction coefficient is small. Therefore, if the surface roughness of the stator side ring 50 and the rotor side ring 54 in the centrifugal bowl 10 of the present invention is approximately the same as that of a conventional centrifugal bowl, the above-described effects are not prevented. For reference, the surface roughness Ra of the stator side ring 50 and the rotor side ring 54 is set to 0.35 μm or less, for example.

  In the above description, the present invention has been described with reference to preferred embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention. Yes.

DESCRIPTION OF SYMBOLS 10 ... Centrifugal bowl 12 ... Stator 14 ... Rotor 50 ... Stator side ring 54 ... Rotor side ring 82 ... Rotation sliding surface W ... Rotation sliding surface width

Claims (2)

A stator provided with an inlet and an outlet for blood or blood components;
A rotor provided rotatably with respect to the stator;
A sealing mechanism having an annular rotary sliding surface between the stator and the rotor,
The radial width of the rotating sliding surface is set to 1370-1530 μm,
A centrifuge characterized by that. The centrifuge of claim 1, wherein
The centrifuge is configured such that the rotor is rotationally driven in a state in which the centrifugal separator is set in a drive device that drives the centrifuge and a predetermined pressing force is applied to the rotating sliding surface. Yes,
The pressing force is 500 g or less.
A centrifuge characterized by that.

Images