EP4640319A1

EP4640319A1 - Centrifugal separator

Info

Publication number: EP4640319A1
Application number: EP22969181.1A
Authority: EP
Inventors: Toshifumi Mitsuyama; Michiru Fujioka; Katsuhiro Kanda
Original assignee: Hitachi High Tech Corp
Current assignee: Hitachi High Tech Corp
Priority date: 2022-12-21
Filing date: 2022-12-21
Publication date: 2025-10-29
Also published as: JPWO2024134793A1; CN120129570A; WO2024134793A1

Abstract

Provided is a centrifuge capable of ensuring that a separation interface, which is the layer interface between sample components separated by centrifugation, is positioned perpendicular to the longitudinal direction of a specimen container without being inclined. A centrifuge 1 includes a specimen container 300, a bucket 110, and a rotor 150. The specimen container 300 stores a specimen, and is mountable directly or indirectly in the bucket 110. The rotor 150 supports and rotates the bucket 110. The bucket 110 is supported by the rotor 150 in such a manner as to be swingable around a first axis A1. The bucket 110 has at least two sub-buckets 122. The plurality of sub-buckets 122 are swingable around a second axis A2. A plurality of the second axes A2 are disposed on different rotor rotation diameters.

Description

Technical Field

The present invention relates to systems and apparatuses that centrifuge blood collection tubes, which are sample containers (specimen containers) used, for example, for blood testing, and collect and test centrifuged components. More particularly, the present invention relates to centrifuges that are suitable for application to testing systems.

Background Art

In recent years, the medical field has been introducing a variety of kinds of automated equipment to save labor for and increase throughput in testing operations. When testing is to be performed in a hospital, test specimens from inpatients and outpatients are collected by various departments of the hospital, and processed in batches in an examination room. Test items for each specimen are communicated to the examination room by a doctor through the use of an online information processing system. Test results are reported online to the doctor from the examination room. Many blood and urine test items require pre-processing for a testing process, such as centrifugation, opening, and dispensing, and these tasks account for a large proportion of overall testing work time.
For general biological sample testing, a dedicated container is prepared, and the biological sample of a patient is collected in the dedicated container and preprocessed. For example, when the biological sample is blood, collected blood is placed into a blood collection tube. Then, the blood collection tube is centrifuged to separate clots and serum from the blood or separate blood cell components and plasma from the blood. This results in the extraction of serum or plasma, which is a component used for analysis.
The extracted serum or plasma may be dispensed into small containers for subsequent testing. The following two conditions may be occasionally imposed on such dispensing.

(1) Collect as much sample as possible.
(2) Avoid sucking sample components not targeted for collection.

For example, in the case of serum collection, there is a risk that a separating agent directly below a serum layer may be mistakenly sucked to clog a dispensing nozzle. Meanwhile, in the case of plasma collection, it may be occasionally desirable to reduce the contamination of blood cell components directly below a plasma layer.
In order to satisfy the above-mentioned conditions, it is desirable to measure the height of a layer interface between the serum and the separating agent and perform a dispensing operation according to the height of the layer interface. For example, there is a liquid level detection device as disclosed in Patent Document 1.
Further, as disclosed in Patent Document 2, a centrifuge unit for centrifugal processing is able to simultaneously process a plurality of specimens. Centrifugal processing utilizes density gradients to separate, for example, blood into its components and acquire components required for testing. A centrifuge built into this centrifuge unit includes adapters for storing a plurality of sample containers, a plurality of buckets for storing the adapters, and a rotor for rotating the buckets. Here, the buckets are attached to the rotor in such a manner as to be rotatable and swingable. This configuration ensures that the buckets are horizontal to a rotor rotation plane due to a centrifugal force generated during rotor rotation, and that the centrifugal force acts on the sample containers stored in the buckets in the direction of insertion (the longitudinal direction of the sample containers). As a result, the components of a sample are separated along the longitudinal direction of the sample container due to density differences. It should be noted that the type of the above-described centrifuge in which the buckets can rotate and swing is called a swing type.

Prior Art Document

Patent Document

Patent Document 1: JP-2022-66509-A
Patent Document 2: JP-2011-25181-A

Summary of the Invention

Problems to be Solved by the Invention

As described above, high throughput is required for testing in hospitals in order to handle a large number of specimens. Therefore, it is demanded that the centrifuges process a plurality of specimens simultaneously.
FIG. 14 depicts a conventional swing-type centrifuge. The following expressions are used below to indicate individual directions.

(1) "Sample container direction" refers to the longitudinal direction of a sample container.
(2) "Centrifugal force direction" refers to the direction in which the centrifugal force acts from the center of rotation during centrifugation. It is the direction from the center of rotation toward the outside of the radius of rotation.

In a case where a conventional swing-type centrifuge handles a large number of sample containers, sample containers 300 may be installed at positions (a in FIG. 14) deviated from the center of the buckets 110 as depicted in FIG. 14. When the sample containers 300 are installed at such positions, the centrifugal force acts in a state (θ in FIG. 14) in which the direction of the centrifugal force is inclined from the directions of the sample containers. Hence, the centrifuged components are deposited in an inclined state. As a result, a separation interface obtained after centrifugation is inclined. Here, the "separation interface" refers to the layer interface between separated sample components. In the case of a blood specimen, the "separation interface" refers, for example, to the interface between serum and separating agent or the interface between plasma and blood cell layer. Further, although the separation interface is originally required to be formed perpendicular to the directions of the sample containers during centrifugation, the word "incline" is used to indicate that the separation interface is inclined from a vertical plane.
The above-mentioned inclined layer interface may cause several problems. One of such problems is that, in an automated system, the inclination of the layer interface in the sample containers makes it difficult to detect the position of the layer interface through the use, for example, of a laser or a camera. This problem may result in the failure to satisfy the above-mentioned conditions imposed on dispensing.
The present invention has been made in view of the above circumstances to provide a centrifuge capable of ensuring that a separation interface, which is the layer interface between sample components separated by centrifugation, is positioned perpendicular to the longitudinal direction of a specimen container without being inclined.

Means for Solving the Problems

In order to solve the above problem, according to an aspect of the present invention, there is provided a centrifuge including a specimen container, a bucket, and a rotor. The specimen container stores a specimen, and is mountable directly or indirectly in the bucket. The rotor supports and rotates the bucket. The bucket is supported by the rotor in such a manner as to be swingable around a first axis. The bucket has at least two sub-buckets. The sub-buckets are swingable around a second axis. A plurality of the second axes are disposed on different rotor rotation diameters.

Advantages of the Invention

The present invention makes it possible to provide a centrifuge capable of ensuring that a separation interface, which is the layer interface between sample components separated by centrifugation, is positioned perpendicular to the longitudinal direction of a specimen container without being inclined.
For example, the sub-buckets in a container holder holding a blood collection tube (specimen container) passively swing and rotate due to the centrifugal force during centrifugation, and the direction of the blood collection tube coincides with the direction of the centrifugal force. As a result, the separation interface is formed vertically without being inclined with respect to the direction of the blood collection tube. Vertical formation of the separation interface improves the accuracy of detecting the position of the layer interface through the use, for example, of a laser or a camera. This ensures that a subsequent dispensing operation can be performed to collect as much sample as possible and avoid sucking sample components not targeted for collection.
Problems, configurations, and advantages other than those described above will become apparent from the following description of embodiments.

Brief Description of the Drawings

FIG. 1 is a schematic diagram illustrating a configuration of a centrifuge according to a first embodiment of the present invention.
FIG. 2 is a diagram illustrating an internal structure of a centrifugal processing unit included in the centrifuge depicted in FIG. 1.
FIG. 3 is a diagram illustrating a configuration of a centrifuge mechanism included in the centrifuge depicted in FIG. 1.
FIG. 4 is a diagram illustrating a state in which an adapter is installed in a bucket depicted in FIG. 3.
FIG. 5 is a diagram illustrating the structure of the adapter depicted in FIG. 4.
FIG. 6 is a diagram illustrating a configuration of an adapter installation section of the centrifuge.
FIG. 7 is a perspective view illustrating a state in which the centrifuge mechanism is placed during centrifugal rotation.
FIG. 8 is a diagram illustrating the positional relation between the center of swinging and the center of gravity of sub-buckets.
FIG. 9 is a diagram illustrating the sub-buckets and a frame during centrifugal rotation.
FIG. 10 is a diagram illustrating the detailed structure of bottom contact sections depicted in FIG. 9.
FIG. 11 is a top view illustrating a state in which the centrifuge mechanism included in the centrifuge is placed during centrifugal rotation.
FIG. 12 is a diagram illustrating a configuration of the centrifuge mechanism included in the centrifuge according to a second embodiment of the present invention.
FIG. 13 is a diagram illustrating a state in which the sub-buckets depicted in FIG. 12 are placed during centrifugation.
FIG. 14 is a diagram illustrating a conventional swing-type centrifuge.

Modes for Carrying Out the Invention

A centrifuge according to embodiments of the present invention includes a specimen container, a container holder, a bucket, and a rotor. The specimen container stores a specimen. A plurality of specimen containers can be placed in the container holder. The container holder can be placed in the bucket. The rotor supports and rotates the bucket. The bucket is supported by the rotor in such a manner as to be swingable around a first axis. The container holder has at least two sub-buckets. The sub-buckets are mounted on the container holder in such a manner as to be swingable around a second axis. A plurality of second axes are disposed on different rotor rotation diameters.
Here, the centrifuge according to the embodiments may be a mechanism for centrifuging a specimen such as a biological sample, or an apparatus, unit, or system in which the mechanism is mounted.
Further, the centrifuge according to the embodiments includes a centrifuge mechanism, and is equipped with the specimen container, the container holder for storing the specimen container, the bucket for storing and retaining the container holder in the centrifuge mechanism, and the rotor for supporting and rotating the bucket. The bucket is connected to the rotor by a first swing axis, and able to incline the specimen container in a predetermined direction during centrifugation. The container holder, which stores the specimen container, is equipped with sub-buckets that are swingable inside. The sub-buckets are connected to a frame of the container holder by second swing axes.
The above-described centrifuge includes at least two sub-buckets in order to simultaneously process a large number of specimens. The second swing axes, which support these sub-buckets, are disposed on different rotor rotation diameters. Here, the "rotation diameter" refers to a straight line that connects the center of rotation of the rotor to the bottom of the bucket in the direction in which the centrifugal force acts.
Moreover, the "container holder" in the above-described configuration is a structure capable of storing and holding the specimen container. For example, in a case where the specimen container is a long cylindrical container such as a blood collection tube, the container holder has a cylindrical hole matching the shape of the specimen container, and is so shaped as to allow the specimen container to be inserted into it.
Further, as a modification of the above-described structure, there is a structure in which the "container holder" and the "bucket" are integral with each other. This structure is for storing a sample container directly in the bucket. Accordingly, the abovementioned sub-buckets are mounted directly into the bucket.
Further, the above-described centrifuge may be configured such that an operator manually sets the specimen container. However, for example, a robot arm for automatically setting a specimen may alternatively be mounted in the above-described centrifuge in order to achieve labor saving and high throughput. The robot arm mentioned here may have a multi-axis joint, or may be configured to have a gripper or another end effector that is mounted on the tip of a linear three-axis (XYZ) actuator.
The "specimen container" is a container for holding a specimen, and may occasionally be referred to as a sample container or a blood collection tube. Further, a specimen may occasionally be referred to as a sample. The following describes an example in which a blood collection tube is used as a specimen container.
The embodiments of the present invention will now be described with reference to the accompanying drawings.

[First Embodiment]

FIG. 1 is a schematic diagram illustrating a configuration of the centrifuge according to a first embodiment of the present invention. In the first embodiment, the specimen is blood, and the specimen container is a blood collection tube.
A centrifuge 1 according to the present embodiment is an apparatus capable of continuously centrifuging a plurality of blood specimens that are to be used for testing.
As depicted in FIG. 1, the centrifuge 1 according to the present embodiment includes a centrifugal processing unit 10 and a transport unit 20. The centrifugal processing unit 10 performs centrifugal processing on blood collection tubes 300. The transport unit 20 sequentially transports the blood collection tubes 300. In the present embodiment, the containers are generically referred to as the blood collection tubes in consideration of blood, which is a representative specimen. However, the containers are not limited to the blood collection tubes and may alternatively be sample containers other than the blood collection tubes.
The centrifuge 1 is connected to other modules, which are not depicted in FIG. 1, through the transport unit 20, which is able to transport the blood collection tubes 300 in a direction A in FIG. 1 by using, for example, a belt mechanism. Here, the other modules include, for example, an input module for inputting the blood collection tubes 300 to test preprocessing systems, a module for capping and uncapping the inputted blood collection tubes 300, and a dispensing module for collecting centrifuged blood components. In these specimen preprocessing systems, the centrifuge 1 according to the present embodiment is able to simultaneously centrifuge an appropriate number of blood collection tubes 300 in accordance with specimen processing specifications for the other modules, and able to process a large number of blood specimens with high throughput by using all of these systems.
Since such a large number of blood specimens are to be handled simultaneously, the centrifugal processing unit 10, which is mounted in the centrifuge 1 according to the present embodiment, and the centrifuge mechanism 100, which is mounted in the centrifugal processing unit 10, are able to suspend and process a plurality of blood collection tubes 300. Specifically, the centrifuge mechanism 100 is able to suspend an adapter 120 for storing the plurality of blood collection tubes 300, all at once. Here, the "adapter" is a generic term for a container that has a plurality of holes into which the blood collection tubes 300 are insertable for storage and that can be inputted to the centrifuge 1, and is referred to as, for example, a bucket insert or a rack. However, the term "adapter" is used here. It should be noted that the adapter is referred to also as a container holder.
The centrifuge 1 has an adapter installation section 50 for temporarily installing the adapter 120, which can be mounted in the centrifugal processing unit 10. Further, the centrifuge 1 is equipped with a blood collection tube gripper 30 and an adapter gripper 40. The blood collection tube gripper 30 grips and transports the blood collection tubes 300. The adapter gripper 40 grips and transports the adapter 120.
The blood collection tube gripper 30 is able to grip, lift, and transfer the blood collection tubes 300. Additionally, the blood collection tube gripper 30 is able to load the uncentrifuged blood collection tubes 300 from the transport unit 20 into the adapter 120, or is able to remove the centrifuged blood collection tubes 300 from the adapter 120 and return the removed blood collection tubes 300 to the transport unit 20.
The adapter gripper 40 is able to grip, lift, and transfer the adapter 120. Additionally, the adapter gripper 40 is able to transport the adapter 120 into which the uncentrifuged blood collection tubes 300 is inserted, from the adapter installation section 50 to the centrifugal processing unit 10, or is able to return the adapter 120 from the centrifugal processing unit 10 to the adapter installation section 50 after centrifugation.
FIG. 2 is a diagram that illustrates an internal structure of the centrifugal processing unit 10, which is included in the centrifuge 1 depicted in FIG. 1, and additionally illustrates a partial cross-section to facilitate the understanding of the internal structure.
As depicted in FIG. 2, the centrifugal processing unit 10 includes the centrifuge mechanism 100, which is described later, and a rotary motor, which is not depicted in FIG. 2 and is configured to drive the centrifuge mechanism 100. The centrifugal acceleration for centrifuging common blood specimens is approximately 1,000 to 2, 000 G, and the centrifuge mechanism 100 is capable of providing such centrifugal acceleration.
The centrifugal processing unit 10 is additionally provided with an opening 11 for placing and removing the adapter 120 having the inserted blood collection tubes 300 in and out of the centrifugal processing unit 10. The adapter gripper 40 places and removes the adapter 120 in and out of the centrifugal processing unit 10 through the opening 11. Hence, the opening 11 is large enough to allow the adapter 120 to be inserted therein while the adapter 120 is gripped by the adapter gripper 40. The opening 11 may additionally be provided with a shutter structure, which is not depicted and configured to be closed during centrifugation.
The adapter 120 into which the blood collection tubes 300 to be centrifuged are inserted is placed in the bucket 110 in order to perform centrifugation in the centrifugal processing unit 10. In this instance, if any blood collection tubes 300 containing centrifuged specimens are left in the centrifugal processing unit 10, such blood collection tubes 300 are removed first.
Since the centrifuge mechanism 100 is of a swing type, the bucket 110 can swing relative to the rotor 150. However, when the rotor 150 is stopped, the opening in the bucket 110 faces upward due to the own weight of the bucket 110. In this state, the adapter gripper 40 is able to set the adapter 120 in the bucket 110 from above.
Here, it should be noted that the centrifuge mechanism 100 in the centrifugal processing unit 10 is provided with a plurality of buckets 110. The rotor 150 of the centrifuge mechanism 100 rotates as needed to ensure that the adapter 120 into which the blood collection tubes 300 to be centrifuged are inserted is placed in the plurality of buckets 110. Subsequently, after the adapter 120 into which the blood collection tubes 300 are inserted is completely placed in all the buckets 110, the rotor 150 rotates to perform centrifugation.
After completion of centrifugation, the centrifuged blood collection tubes 300 are collected. In this instance, the adapter 120 into which the centrifuged blood collection tubes 300 are inserted is transferred from the centrifuge mechanism 100 to the adapter installation section 50. Subsequently, the centrifuged blood collection tubes 300 are transported to the transport unit 20 by the blood collection tube gripper 30, and transferred to a module configured to perform the next process.
FIG. 3 is a diagram illustrating a configuration of the centrifuge mechanism 100 included in the centrifuge 1 depicted in FIG. 1 . FIG. 4 is a diagram illustrating a state in which the adapter 120 into which the blood collection tubes 300 are inserted is installed in the bucket 110.
As depicted in FIG. 3, the centrifuge mechanism 100 according to the present embodiment is configured such that a total of four buckets 110 are attached to the rotor 150 at 90-degree intervals. As depicted in FIG. 4, cylindrical grooves 111 are formed on the outer surface of each bucket 110. Further, cylindrical protrusions are formed on bucket mounting sections of the rotor 150. The cylindrical grooves 111 and the cylindrical protrusions are fitted together in such a manner as to be allowed to relatively rotate and swing. The above-described structure causes the bucket 110 to swing due to the centrifugal force generated by rotation of the rotor 150 during centrifugation. Here, a rotation axis A1 around which the bucket 110 swings is defined as the first swing axis.
As depicted in FIGS. 3 and 4, the adapter 120 into which the blood collection tubes 300 are inserted is installable in the bucket 110. In a state in which the adapter 120 is installed in the bucket 110, a part of the outer wall of the adapter 120 is fitted into the inner wall of the bucket 110 to fix the position of the adapter 120. Thus, even during a centrifugal operation, the position of the adapter 120 remains unchanged relative to the bucket 110.
FIG. 5 is a diagram illustrating the structure of the adapter 120 depicted in FIG. 4. The adapter 120 includes a frame 121 and two sub-buckets 122. In the present embodiment, three blood collection tubes 300 are inserted into each of the sub-buckets 122, and the sub-buckets 122 are able to swing with respect to the frame 121. That is, the adapter 120 in the present embodiment is able to store a total of six blood collection tubes.
Here, the sub-buckets 122 are attached to the frame 121 by swing shafts 123. The swing shafts 123 allow the sub-buckets 122 to swing relative to the frame 121. Here, a rotation axis A2 around which the sub-buckets 122 swing is defined as the second swing axis. The second swing axis supporting the sub-buckets 122 is in a direction perpendicular to the first swing axis, which supports the buckets. As described above, a plurality of blood collection tubes 300 are placed in the sub-buckets 122, and are arranged in series in the direction of the rotation axis A2 of the swing shafts 123 (the direction of an arrow B in FIG. 5).
The frame 121 and the sub-buckets 122 included in the adapter 120 in the present embodiment are formed by a material that is strong enough not to be destroyed by the centrifugal force during centrifugation. In the present embodiment, it is assumed that the frame 121 and the sub-buckets 122 are formed by a resin member (polyphenylene ether or polyacetal). However, they may partially be formed by a metal material. Further, in the present embodiment, the frame 121 has grooves into which the swing shafts 123 of the sub-buckets 122 are fitted and structured for sliding rotation. However, such a rotating structure may use, for example, a bearing.
FIG. 6 is a diagram illustrating a configuration of the adapter installation section 50 of the centrifuge 1. The centrifuge 1 according to the present embodiment allows a plurality of adapters 120 to be installed in the adapter installation section 50. Here, the adapters 120 wait in the adapter installation section 50 until a predetermined number of uncentrifuged blood collection tubes 300 are set in position in the adapters 120. Subsequently, after the predetermined number of blood collection tubes 300 are set by the blood collection tube gripper 30, the adapters 120 are transported from the adapter installation section 50 to the centrifugal processing unit 10 by the adapter gripper 40.
Subsequently, upon completion of centrifugation by the centrifugal processing unit 10, the adapters 120 storing the centrifuged blood collection tubes 300 are transported again by the adapter gripper 40 from the centrifugation unit 10 to the adapter installation section 50. Then, the centrifuged blood collection tubes 300 are transferred from the adapters 120 to the transport unit 20 by the blood collection tube gripper 30.
In the above operation, the blood collection tubes 300 need to be inserted into or removed from swinging sub-buckets 122 by the blood collection tube gripper 30. To prevent the posture of the sub-buckets 122 from changing during this operation, the adapter installation section 50 is provided with a support member 501 that comes into contact with the bottom surface of the sub-buckets 122 to suppress swinging. As a result, while the adapters 120 are placed in the adapter installation section 50, the swinging of the sub-buckets 122 is restricted. Consequently, no hindrance that could be caused by the swinging of the sub-buckets 122 would occur when the blood collection tube gripper 30 inserts or removes the blood collection tubes 300.
Here, the support member 501 may be shaped to fit into the shape of the bottom of the sub-buckets in order to suppress the rotation of the sub-buckets, and may be configured to come into contact with a high friction member, such as rubber, or with an elastic body with a relatively low Young's modulus.
The operation of the centrifuge mechanism 100 will now be described. FIG. 7 is a perspective view illustrating a state in which the centrifuge mechanism 100 is placed during centrifugal rotation. Here, the rotor 150 is rotated in the direction of an arrow C in FIG. 7 by an external motor.
In the above instance, the centrifugal force acts in the radial direction of the rotation circle (an arrow R in FIG. 7) from a rotation axis 150A of the rotor. This centrifugal force causes the bucket 110 to rotate around the rotation axis A1, which is the first swing axis, and causes the blood collection tubes 300 to swing and rotate in such a manner that the bottom of the blood collection tubes 300 faces the direction of the centrifugal force (the arrow R in FIG. 7).
Here, the direction in which the centrifugal force acts from the center of rotation during centrifugation is referred to as the "centrifugal force direction." This is the direction from the center of rotation toward the outside of the rotation radius. Further, the longitudinal direction of the blood collection tubes 300 is referred to as the "blood collection tube direction."
The centrifugal force causes the bucket 110 to rotate and swing in such a manner that its bottom faces the centrifugal force direction, and all the blood collection tubes 300 set in the centrifuge mechanism 100 are oriented horizontally with respect to the centrifugal force direction.
FIG. 8 is a diagram illustrating the positional relation between the center of swinging and the center of gravity of the sub-buckets 122 in a state where the blood collection tubes 300 are inserted into position. Here, the "rotation radius" is defined as a straight line R0 that connects the rotation center axis 150A of the rotor 150 to the bottom of the bucket in the centrifugal force direction.
In the present embodiment, a plurality of sub-buckets 122 are placed in the adapter 120. Although two sub-buckets 122 are provided in the present embodiment, the rotation/swing centers 123C of these sub-buckets 122 are on different rotation radii. That is, a rotation radius R1 passing through the rotation/swing center 123C of one sub-bucket 122 and a rotation radius R2 passing through the rotation center 122C of the other sub-bucket 122 are different straight lines that do not intersect with each other.
Further, the shape and the configuration of the sub-buckets 122 are determined in such a manner that a position of the center of gravity 122G of the sub-buckets 122 into which the blood collection tubes 300 are inserted falls within a hatched region V in FIG. 8, that is, within the range from the rotation radius R1 toward a rotation radius R0 or within the range from the rotation radius R2 toward the rotation radius R0. In other words, the position of the center of gravity 122G of the sub-buckets 122 is located closer to the center of the bucket 110 than to the center of the rotation axis A2 of the swing shafts 123. In order to adjust the position of the center of gravity 122G as described above, for example, the sub-buckets 122 may be formed, for example, by a member formed by a plurality of materials. Preferably, a material with a relatively high specific gravity is selected for the bottom of the sub-buckets 122 as compared to the other portions of the sub-buckets 122.
Since the position of the center of gravity 122G of the sub-buckets 122 into which the blood collection tubes 300 are inserted is set as described above, a rotational moment acts on the sub-buckets 122 in the direction of an arrow M in FIG. 8 due to the centrifugal force F acting on the position of the center of gravity 122G during a centrifugal operation. This rotational moment causes the sub-buckets 122 to swing in such a direction that the blood collection tube direction of the blood collection tubes 300 coincides with the centrifugal force direction.
FIG. 9 is a diagram illustrating the states of the sub-buckets 122 and the frame 121 during a centrifugal operation. The frame 121 has bottom contact sections 130 that come into contact with the bottom of the sub-buckets 122, which swing and rotate during centrifugal rotation. The bottom contact sections 130 have the function of suppressing excessive rotation of the sub-buckets 122 that rotate in the direction of the arrow M in FIG. 9. That is, the position of the bottom contact sections 130 is set to ensure that the sub-buckets 122 stop swinging at a position where the blood collection tube direction of the blood collection tubes 300 coincides with the centrifugal force direction.
Further, the bottom contact sections 130 additionally have the function of preventing the centrifugal force F acting on the sub-buckets 122 from concentrating on their swing shafts 123. The centrifugal force F proportional to the mass and centrifugal acceleration of the sub-buckets 122 acts on the sub-buckets 122 during centrifugation. This centrifugal force F acts on the swing shafts 123 of the sub-buckets 122. If such centrifugal force F acts only on the swing shafts 123, a repeated load may act to damage or destroy the swing shafts 123. Hence, the present embodiment is configured such that the bottoms of the sub-buckets 122 come into contact with the bottom contact sections 130 of the frame 121 while the sub-buckets 122 are rotating and swinging. This results in a structure in which the centrifugal force F acting on the sub-buckets 122 is received at two points, that is, the swing shafts 123 of the sub-buckets 122 and the bottom contact sections 130. Consequently, the load caused by the centrifugal force will not concentrate on the swing shafts 123 of the sub-buckets 122.
FIG. 10 is a diagram illustrating the detailed structure of the bottom contact sections 130 that are formed on the frame 121. As depicted in FIG. 10, the bottom contact sections 130 may be shaped like ribs. The ribs come into contact with the sub-buckets 122 during centrifugation to allow a part of the centrifugal force F to act thereon. For this reason, a material with excellent wear resistance should preferably be selected for the ribs. It should be noted that FIG. 10 depicts an example in which there are three ribs. However, the number of ribs is not limited to three. Further, the ribs need not necessarily be semi-cylindrical in shape.
FIG. 11 is a top view illustrating a state in which the centrifuge mechanism 100 included in the centrifuge 1 is placed during centrifugal rotation. In FIG. 11, a part of the bucket 110 is cross-sectionally depicted to indicate the state of the sub-buckets 122. In the centrifuge mechanism 100 according to the present embodiment, the blood collection tube direction of the blood collection tubes 300 coincides with the centrifugal force direction during centrifugation as depicted in FIG. 11. Hence, for example, blood components, such as blood cells, and a separating agent for separating the blood components are deposited in the blood collection tube direction. As a result, the separation interface is perpendicular to the blood collection tube direction.
When the rotation stops after the centrifugal operation, the opening in the bucket 110 faces upward due to the own weight of the bucket 110. In this state, the adapter 120 can be removed from the upper part of the bucket 110 by the adapter gripper 40.
Further, the sub-buckets 122 return to a state before the start of the centrifugal operation due to their own weight. That is, the blood collection tube direction follows the direction of gravity. As a result, after completion of centrifugation, the separation interface formed perpendicular to the blood collection tube direction does not lose its shape or become inclined due to the own weight.
Moreover, the swingable sub-buckets 122 in the present embodiment also serve to buffer the force acting on the blood collection tubes 300 in the direction of rotation during the centrifugal operation. When the rotor 150 rotates at high speed for centrifugation, acceleration and deceleration operations are required. However, as the rotor 150 accelerates and decelerates, inertial force proportional to the mass of the adapter 120 and the blood collection tubes 300 acts on the bucket 110. In this instance, as long as the sub-buckets 122 have a swingable structure, frictional force caused by the swinging parts of the sub-buckets 122, that is, the frictional force caused by the swing shafts 123 of the sub-buckets 122 and the swinging part of the frame 121, reduces the inertial force acting on the blood collection tubes 300. This effect also makes it possible to inhibit the shape of the centrifuged separation interface from being distorted or inclined.
The centrifuge 1 according to the present embodiment is configured such that the separation interface of a centrifuged specimen is formed perpendicular to the blood collection tube direction. This improves the accuracy of detecting the position of a layer interface after centrifugation through the use, for example, of a laser or a camera. As a result, a subsequent dispensing operation can be performed in such a manner as to collect as much sample as possible and avoid sucking sample components not targeted for collection.
As described above, the present embodiment makes it possible to provide a centrifuge that is able to ensure that the separation interface, which is the layer interface between centrifuged sample components, is positioned perpendicular to the longitudinal direction of the specimen container without being inclined.
For example, the sub-buckets in the container holder for storing the blood collection tubes (specimen containers) passively swing and rotate due to the centrifugal force during centrifugation, and the blood collection tube direction coincides with the centrifugal force direction. As a result, the separation interface is formed vertically without being inclined with respect to the blood collection tube direction. The vertically-formed separation interface improves the accuracy of detecting the position of the layer interface through the use, for example of a laser or a camera. This ensures that a subsequent dispensing operation can be performed to collect as much sample as possible and avoid sucking sample components not targeted for collection.

[Second Embodiment]

FIG. 12 is a diagram illustrating a configuration of the centrifuge mechanism included in the centrifuge 1 according to a second embodiment of the present invention. The second embodiment differs from the first embodiment in that the sub-buckets 122 in the second embodiment are directly mounted in the bucket 110. The other component elements in the second embodiment are similar to those in the first embodiment. The component elements similar to those in the first embodiment are designated by the same reference symbols and will not be redundantly described.
FIG. 12 is a diagram illustrating the configuration of the centrifuge mechanism 100 according to the second embodiment. FIG. 13 is a diagram illustrating a state in which the sub-buckets 122 are placed during centrifugation. In the present embodiment, the sub-buckets 122 are structured for being directly mounted in the bucket 110. Further, a total of four sub-buckets 122 are mounted in the bucket 110, and five blood collection tubes 300 are inserted into each of the sub-buckets 122. That is, the structure in which the sub-buckets 122 (referred to also as the container holders) are directly mounted in the bucket 110 means a structure in which the container holders are swingably mounted directly in the bucket 110.
In the present embodiment, four sub-buckets 122 are mounted in the adapter 120. The rotation/swing center 123C of each of these sub-buckets 122 exists on different rotation radii. That is, the rotation radii R1 to R4, which pass through the rotation/swing center 123C of one of the sub-buckets 122, are separate straight lines.
When the centrifuge mechanism 100 starts rotating, the blood collection tubes 300 rotate in the direction in which the blood collection tube direction coincides with the centrifugal force direction, as in the first embodiment. Further, as in the first embodiment, the rotation of the sub-buckets 122 can be limited to a desired amount of rotation by the bottom contact sections, which are not depicted in FIG. 13 but are formed in the bucket 110.
As described above, in addition to the advantages provided by the first embodiment, the second embodiment has a structure in which the sub-buckets 122 can be directly mounted in the bucket 110. This makes it possible to reduce the number of parts. Furthermore, it is possible to increase the number of sub-buckets 122 mountable in the bucket 110 and thus achieve high throughput as a centrifuge.
The centrifuge according to the above-described first and second embodiments is used in a testing system for, for example, blood testing, but is not limited to such uses. For example, the centrifuge according to the above-described embodiments is additionally applicable in other fields that use centrifugation, for instance, for preparation and processing of biological samples.
Additionally, the present invention is not limited to the foregoing embodiments, and extends to various modifications. For example, the foregoing embodiments are described in detail to facilitate the understanding of the present invention in an easy-to-understand manner. The configuration of the present invention is not necessarily limited to those including all of the component elements described above. Moreover, some component elements of one of the embodiments may be replaced by the component elements of another embodiment, or may be subjected to the addition of the component elements of another embodiment.

Description of Reference Symbols

1:: Centrifuge
10:: Centrifugal processing unit
11:: Opening
20:: Transport unit
30:: Blood collection tube gripper
40:: Adapter gripper
50:: Adapter installation section
100:: Centrifuge mechanism
110:: Bucket
111:: Cylindrical groove
120:: Adapter
121:: Frame
122:: Sub-bucket
123:: Swing shaft
130:: Bottom contact section
150:: Rotor
300:: Blood collection tube
501:: Support member

Claims

A centrifuge comprising:
a specimen container that stores a specimen;

a bucket in which the specimen container is mountable directly or indirectly; and

a rotor that supports and rotates the bucket,

wherein the bucket is supported by the rotor in such a manner as to be swingable around a first axis,

the bucket has at least two sub-buckets,

the plurality of sub-buckets are swingable around a second axis, and

a plurality of the second axes are disposed on different rotor rotation diameters.
The centrifuge according to claim 1, further comprising:
a container holder in which the specimen container is mountable,

wherein the specimen container is mounted indirectly in the bucket via the container holder, and

the plurality of sub-buckets are swingably mounted on the container holder via the second axis.
The centrifuge according to claim 1,
wherein the plurality of sub-buckets are swingably mounted directly in the bucket via the second axis.
The centrifuge according to claim 1,
wherein the first axis is perpendicular to the second axis.
The centrifuge according to claim 3,
wherein the first axis is perpendicular to the second axis.
The centrifuge according to claim 4,
wherein the bucket has a contact section that comes into contact with the sub-buckets in a direction in which centrifugal force of the sub-buckets acts when the sub-buckets swing.
The centrifuge according to claim 5,
wherein the bucket has a contact section that comes into contact with the sub-buckets in a direction in which centrifugal force of the sub-buckets acts when the sub-buckets swing.
The centrifuge according to claim 4,
wherein a position of a center of gravity of the sub-buckets is located closer to a center of the bucket than to a center of the second axis.
The centrifuge according to claim 5,
wherein a position of a center of gravity of the sub-buckets is located closer to a center of the bucket than to a center of the second axis.
The centrifuge according to claim 4,
wherein the bucket has a contact section that comes into contact with the sub-buckets in a direction in which centrifugal force of the sub-buckets acts when the sub-buckets swing, and

a position of a center of gravity of the sub-buckets is located closer to a center of the bucket than to a center of the second axis.
The centrifuge according to claim 5,
wherein the bucket has a contact section that comes into contact with the sub-buckets in a direction in which centrifugal force of the sub-buckets acts when the sub-buckets swing, and

a position of a center of gravity of the sub-buckets is located closer to a center of the bucket than to a center of the second axis.