Patent Application
20110319247
The present invention relates to a centrifuge for use in medical, pharmaceutical, genetic engineering fields, chemical, foods production and pharmaceuticals production industries and more particularly to a sample container for a centrifuge with an angle rotor which can increase an amount of liquid sample to be processed at one time.
A centrifuge for use in separating liquid samples includes a rotor in which a plurality of sample containers containing a liquid sample are held in sample container holding holes which are disposed at equal intervals in a circumferential direction and a driving unit such as a motor for driving to rotate the rotor. The centrifuge collects target substances by rotating the rotor at high speeds within a rotor chamber under the atmospheric or reduced pressure for centrifugally separating the liquid samples in the sample containers. Maximum rotation speeds of centrifuges to which the invention is mainly applied range approximately from 5,000 to 30,000 rpm and in such centrifuges, rotors of various specifications can be used in accordance with applications.
Liquid samples to be processed by such centrifuges include blood constituents, culture solutions of bacteria or viruses, organic constituents such as liquids containing DNA or RNA, polymeric aqueous suspensions, inks and food processing liquids. These liquid samples are subjected to centrifugal separation for various purposes in steps of research and experiment, inspection, production and the like.
For example, JP-A-2008-119649 discloses a known centrifuge rotor.
As to sample containers 250 with a lid for use in angle rotors 230 like the rotor 230 described above, several types of sample containers 250 having different capacities ranging from on the order of 2 ml/container to 1000 ml/container are put in a practical use according to applications. The number of sample container holding holes 232 to be formed in the rotor 230 ranges variously from 4/rotor to on the order of 20/rotor. In general, these angle rotors 230 are formed by use of an aluminum alloy, a titanium alloy or a carbon fiber composite material. Several types of large-capacity angle rotors 230 are commercially available which include, for example, a rotor which accommodates 6 sample containers of 300 ml (hereinafter, referred to as a “300 ml×6 rotor”), a 500 ml×6 rotor and a 1,000 ml×4 to 6 rotor. As time goes by, the capacity of sample containers increases. In addition, as the capacity of sample containers increases, the size of rotors also increases. For example, rotors which employ sample containers of 300 ml to 1,000 ml include a rotor body of which a maximum diameter exceeds 300 mm in general.
Incidentally, the replacement of rotors of a centrifuge is performed by the operator. The manufacturers of centrifuges including the applicant of this patent application have made every effort to reduce the weight of rotors and increase the operability thereof. Further, the amount of sample to be centrifugally separated at one time has been attempted to be increased in association with the increase in capacity of sample containers. In recent years, centrifuges installing a large-capacity angle rotor of 1,000 ml×4 are now widely used. In addition, JP-A-2004-290746 discloses sample containers employed having a lid, and removal through holes 252A are formed in a lid 252 for facilitation of removal thereof and which prevent the leakage of a sample contained thereof during centrifugal separation.
In general, in order to collect target substances from liquid samples in a centrifugal separation process with good efficiency, a centrifugal acceleration imparted to liquid samples is increased by increasing the rotation speed of a rotor, so as to increase the centrifugal effect for quick settlement of target substances or to increase the recovery rate, so that the amount of sample that can be processed at one time is increased. In addition, in order to reduce costs involved in centrifugal separation, it is preferable to fabricate an inexpensive centrifuge including a rotor and further to increase the yield of centrifugal separation by increasing the amount of sample that can be subjected to centrifugal separation at one time.
In order to process a large amount of liquid sample by centrifugal separation at one time, it is effective to increase the number of sample containers attached in the rotor or to increase the capacity of each sample container. However, in order to increase the capacity of the conventional cylindrical sample container as it is, it is necessary to increase the outside diameter of the body portion 251 or to increase the height thereof. As this occurs, in the rotor, one sample container holding hole interferes with an adjacent holding hole, and therefore, it is necessary to shift the position where the holding holes are disposed further radially outwards (towards an outer circumferential side) from the rotation center. As a result, the diameter of the rotor itself is increased, which increases the mass of the rotor, and the carriage or attachment and detachment of the rotor to and from the centrifuge by the operator is deteriorated.
In addition, the increase in diameter of the rotor leads to an increase in air resistance (windage loss), and therefore, as countermeasures thereagainst, it is necessary to increase the output of the drive unit of the centrifuge and to increase the output of a cooling system for cooling the rotor. Further, the rotor chamber (the chamber) of the centrifuge needs to be enlarged in association with the increase in diameter of the rotor, and this increases the area where the centrifuge is installed, causing a problem that the price of the centrifuge is increased.
In the process of solving these problems, the inventors paid attention to the fact that rotor constituting member portions (hereinafter, referred to as “excess portions”) which constitute a cause for an increase in weight exist between the adjacent sample container holding holes when the rotor which holds the cylindrical sample containers is viewed from above and tried to reduce these excess portions to as low level as possible for improvement in weight reduction. In addition, in the process of improving the weight reduction, the inventors also found out that the excess portions in the vicinity of the outer circumference of the rotor constituted one of causes for increasing the mass of the rotor and that the excess portions caused a reduction in strength of the rotor due to centrifugal load exerted to these excess portions.
In view of the above, an object of one aspect of the disclosure is to provide a centrifuge sample container which can increase an amount of sample to be subjected to centrifugal separation at one time while suppressing the increase in diameter and weight of the rotor.
Another object is to provide a centrifuge sample container which enables centrifugal separation work to be carried out with good efficiency within a short period of time by increasing the centrifugal separation performance.
A further object is to provide a centrifuge sample container which can prevent an attachment failure of auxiliary members, which can avoid as much possibility to reduce its service life as possible, which has superior durability and which is easy to be handled.
The aspect of the disclosure provides the following arrangements:
a body portion configured to contain a sample and having a circular opening portion in an upper portion of the body portion; and
a cap portion configured to be engaged with and attached on the body portion,
wherein the body portion has a substantially triangular external shape defining three apex portions and three side portions between two of the apex portions when viewed from above,
wherein distances between centers of the apex portions are equal to one another,
wherein each of the apex portions is formed with a first radius of curvature when viewed from above, and
wherein each of the side portions is formed into a outwardly curved arc-like shape with a second radius of curvature when viewed from above.
an outline of the external shape of the body portion is located further outwards than the opening portion when viewed from above, and
a neck support portion having the same shape as the external shape of the body portion is formed on the cap portion.
the cap portion includes:
an inner lid which is secured in the opening portion while a closing member is interposed between an upper end face of the opening portion and the inner lid; and
an outer lid which is engaged with the body portion so as to cover the opening portion and the inner lid, and
the neck support portion is formed on the outer lid.
wherein the outer lid includes a lower inner circumferential surface formed into a cylindrical shape,
wherein when the cap portion is engaged with the opening portion by the engaging unit, the substantially triangular shape of the body portion coincides with a substantially triangular shape of the outer lid when viewed from above.
the engaging unit includes a projecting portion which is formed on the inner circumferential surface and projects radially inwardly,
the engaging unit includes a circumferential groove which is formed on an outer circumferential side of the opening portion, and
the cap portion is held so as not to be shifted in an axial direction when the projecting portion enters the circumferential groove.
the engaging unit includes:
an axial groove which is formed on the body portion extends from an opening surface of the opening portion in an axial direction; and
a circumferential groove which extends in a circumferential direction from a distal end side of the axial groove, and
the cap portion is pushed axial downwards relative to the body portion and is then turned through a predetermined angle so that the projecting portion is positioned in the circumferential groove.
a length of the circumferential groove which extends from the axial groove is set so that a rotation angle of the cap portion becomes smaller than about 120 degrees in the circumferential direction.
a through hole in which a thread is formed is provided in the outer lid, and
a push piece configured to push the inner lid is attached in the through hole.
a body portion configured to contain a sample and having a circular opening portion in an upper portion of the body portion;
a cap portion configured to be attached on the body portion;
an engaging unit configured engage the cap portion with the body portion,
wherein the cap portion includes:
an inner lid which is secured in the opening portion while a closing member is interposed between an upper end face of the opening portion and the inner lid; and
an outer lid which is engaged with the body portion so as to cover the opening portion and the inner lid, and
wherein the outer lid includes a lower inner circumferential surface formed into a cylindrical shape,
wherein the engaging unit is provided on an outer circumferential surface of the opening portion and the inner circumferential surface of the outer lid,
wherein a through hole is formed through the outer lid and a thread is formed on the through hole, and
wherein a push piece configured to push the inner lid is attached in the through hole.
the engaging unit includes a projecting portion which is formed on the inner circumferential surface and projects radially inwardly, and
the engaging unit includes a circumferential groove which is formed on the outer circumferential surface of the opening portion, and
the cap portion is held so as not to be shifted in an axial direction when the projecting portion enters the circumferential groove.
the engaging unit includes:
an axial groove which is formed on the body portion extends from an opening surface of the opening portion in an axial direction; and
a circumferential groove which extends in a circumferential direction from a distal end side of the axial groove, and
the cap portion is pushed axial downwards relative to the body portion and is then turned through a predetermined angle so that the projecting portion is positioned in the circumferential groove.
a length of the circumferential groove which extends from the axial groove is set so that a rotation angle of the cap portion becomes smaller than about 120 degrees in the circumferential direction.
a rotor which includes a holding portion;
a motor which is configured to rotate the rotor;
a rotor chamber which accommodates the rotor; and
the centrifuge sample container described in (1), which is attached in the holding portion of the rotor.
a rotor which includes a holding portion;
a motor which is configured to rotate the rotor;
a rotor chamber which accommodates the rotor; and
the centrifuge sample container described in (10), which is attached in the holding portion of the rotor.
According to the first aspect, the body portion has the substantially triangular external shape when viewed from above and has the circular opening portion in the upper portion thereof and the cap portion can be attached to and detached from the body portion through engaging. Thus, compared with the conventional cylindrical sample container, the sample container can be realized which can easily be attached and detached while containing a large amount of sample. In addition, the body portion is formed by combining the plurality of shapes with the different radii of curvatures, and therefore, the strength of the sample container can be increased.
According to the second aspect, the neck support portion having the same shape as the external shape of the body portion is formed integrally on the cap portion. Therefore, the operator does not have to worry about the failure to attach the neck support member, and the deformation or failure of the lid portion and the opening portion of the sample container due to the centrifugal force can be prevented. In addition, even in the event that the centrifugal force is applied thereto, since the shape of the outer circumferential portion of the outer lid matches the shape of the sample container holding hole in the rotor and the outer lid fits in the sample container with no gap formed therebetween, the deformation of the opening portion of the sample container and the cap portion due to the centrifugal force can be prevented.
According to the third aspect, the cap portion is formed so as to have the inner lid which is fittingly secured in the opening portion to thereby interpose the closing member between the upper end face of the opening portion and itself and the outer lid which is engaged with the body portion so as to cover the opening portion and the inner lid, and the neck support portion is formed on the outer lid. Thus, the sample container can be provided which ensures the sealing of the container without damaging the sealing performance of containing the sample liquid therein without any leakage therefrom.
According to the fourth aspect, when the cap portion is engaged with the opening portion by the engaging unit, the substantially triangular shape of the body portion and the substantially triangular shape of the outer lid coincide with each other in position when viewed from above. Thus, when the cap portion is not fastened properly, the substantially triangular shape of the body portion and the substantially triangular shape of the outer lid do not coincide with each other in position. Therefore, the operator can visually confirm at a glance whether the sample container is closed properly or is left open. In addition, the sample container cannot be attached in the holding hole in the rotor unless the cap portion is properly closed. Therefore, there can be eliminated a risk of leakage of the sample due to the failure to fasten the cap portion properly.
According to the fifth aspect, the engaging unit is formed by the projecting portion on the cap portion and the circumferential groove which is formed on the outer circumferential side of the opening portion, and therefore, the engaging unit can easily be fabricated in the molding process of the cap portion and the sample container, thereby making it possible to suppress the fabrication costs to an inexpensive level. In addition, the projecting portion and the groove portion can be formed much wider than the pitch of the thread, thereby making it possible to realize the sample container which is easy to be washed and handled.
According to the sixth aspect, the plurality of engaging unit like the engaging unit are provided circumferentially on the cap portion and the plurality of engaging unit like the engaging unit are provided circumferentially on the body portion. Therefore, the cap portion can be fixed to the body portion in an ensured fashion.
According to the seventh aspect, the length of the circumferential groove which extends from the axial groove is set so that the rotation angle of the cap portion becomes smaller than about 120 degrees in the circumferential direction, and therefore, the operator can easily open and close the cap portion only by twisting it by one hand.
According to the eighth aspect, the length of the circumferential groove which extends from the axial groove is set so that the rotation angle of the cap portion becomes smaller than about 120 degrees in the circumferential direction, and therefore, engaging unit can be disposed at three locations or more in the circumferential direction, thereby making it possible to hold the cap portion stably.
According to the ninth aspect, the through hole in which the thread is formed is provided in the outer lid, and the push piece adapted to push the inner lid is installed in the through hole. Therefore, the closing member between the sample container and the inner lid can be compressed, thereby making it possible to ensure a sufficient sealing performance of the sample container to prevent the leakage of the sample therefrom.
According to the tenth aspect, the cap portion can be attached to and detached from the body portion through engaging, and therefore, the operator can easily open and close the sample container only by twisting the cap portion by one hand. In addition, the through hole in which the thread is formed is provided in the outer lid, and the push piece adapted to push the inner lid is installed in the through hole. Therefore, the closing member between the sample container and the inner lid can be compressed sufficiently, thereby making it possible to ensure a sufficient sealing performance of the sample container to prevent the leakage of the sample therefrom.
According to the eleventh aspect, the cap portion is held so as not to be shifted axially when the projecting portion on the outer lid enters the circumferential groove. Therefore, the cap portion can be held firmly so as not to be dislodged from the body portion even though the cap portion is configured so as to easily be attached to and detached from the body portion.
According to the twelfth aspect, the plurality of engaging unit like the engaging unit are provided circumferentially on the cap portion and the plurality of engaging unit like the engaging unit are provided circumferentially on the body portion. Therefore, the cap portion can be fixed to the body portion in an ensured fashion.
According to the thirteenth aspect, the length of the circumferential groove which extends from the axial groove is set so that the rotation angle of the cap portion becomes smaller than about 120 degrees in the circumferential direction, and therefore, the operator can easily open and close the cap portion only by twisting it by one hand.
According to the fourteenth aspect, the length of the circumferential groove which extends from the axial groove is set so that the rotation angle of the cap portion becomes smaller than about 120 degrees in the circumferential direction, and therefore, engaging unit can be disposed at three locations or more in the circumferential direction, thereby making it possible to hold the cap portion stably.
Hereinafter, exemplary embodiments of the invention will be described by reference to the drawings. In the drawings, same reference numerals will be given to same portions, and the repetition of the same description will be omitted. In this specification, directions shown in
A drive unit 5 is attached to the partition plate 2A within the lower space partitioned by the partition plate 2A within the housing 2. The drive unit 5 includes a motor housing 6, and an electric motor 7 is provided in an interior of the motor housing 6 as a drive source. The motor housing 6 is fixed to the partition plate 2 via a damper 8. A shaft support portion 6A is disposed on an upper side of the motor housing 6 so as to extend through a bottom portion of the chamber 3 to reach an interior of the rotor chamber 4. A rotational shaft 7A of the motor 7 is supported rotatably by the shaft support portion 6A and extends upwards as far as the interior of the rotor chamber 4. A drive shaft portion 12 is provided at an upper end portion of the rotational shaft 7A, and a drive shaft hole 31A is fixed to the drive shaft portion 12. The rotor 30 is detachably attached on the drive shaft portion 12 and is rotated by the motor 7. Normally, a rotor 30 is selected for installation, which has a number of holding holes which corresponds to a number of sample containers to be used. Sample containers 50 filled with samples are attached in the holding holes 32 formed in the rotor 30.
Nest, the rotor and the sample container will be described by reference to
An opening portion 51A is provided in an upper portion of the sample container 50, and a cap portion 52 is attached to the opening portion 51A. The cap portion 52 is made up of an outer lid 53 and an inner lid 54, and the opening portion 51A is sealed up by screwing the cap portion 52 to the opening portion 51A. It is characteristic of this embodiment that a distance L1 in a normal direction from a vertical center line 35 of the sample container 50 to an inner circumferential side wall of the container is much larger than a distance L2 from the center line 35 to an outer circumferential side wall of the container. On the other hand, in the opening portion 51A, a distance C1 from the center line 35 to an inner side of the opening portion is equal to a distance C2 to an outer side thereof. Note that these distances L1, L2, C1, C2 are measured in the normal direction from the center line 35. In addition, the center line 35 is a line which passes through a center position of the cap portion 52 or the opening portion 51A. The center line 35 is an imaginary line which passes through a center position (or the center of gravity) of a bottom surface of the container 50 and the center position of the cap portion 52 (a position where a projecting portion 54A, which will be described later, is present). A vertical positional relationship is established between the center line 35 and an upper surface of the outer lid 53.
The shape and number of through holes 53A are arbitrary, provided that the sample container 50 can be taken out easily. However, it is desirable that the through hole 53A is sized so as to admit the entrance of the tip of a finger, particularly, the thumb of the adult, and therefore, the through hole 53A has desirably a diameter of the order of 20 mm. Note that the through holes 53A do not always have to be provided. In the case of the rotor 30 of this embodiment, since the sample container 50 can be pulled out from the rotor body 31 by gripping the outer circumferential side of the cap portion 52, no through hole 53A may be provided. Slip preventive projections 53B are provided at equal intervals in a circumferential direction on an outer circumferential portion of the outer lid 53 so that the operator can grip to rotate the cap portion 52 easily.
The body portion 51 of the sample container 50 has a cross-sectional shape having substantially a regular triangle. Specifically, side portions (side portions 56A, 56B, 56C, in which the side portion 56C will be described later) of the regular triangle are formed into a curved surface with a large radius of curvature which is curved outwards moderately convexly, and three apex portions (apex portions 55A, 55B, 55C, in which the apex portion 55B will be described later) of the regular triangle are formed into a curved surface with a small radius of curvature. A flat shoulder portion 51D is formed horizontally outwards of the male thread portion 51B of the body portion 51. An outer edge of the shoulder portion 51D is contoured into a substantially triangular shape (a rice ball shape) when viewed from above.
The shoulder portion 51D and the side portions 56A to 56C and the apex portions 55A to 55C are connected by a moderate curved surface with a small radius of curvature as viewed in a vertical section. This portion constitutes a connecting portion extending from the shoulder portion to the side portions and extending from the shoulder portion to the apex portions. The strength of the sample container at this portion is increased by forming the portion so as to have as small a radius of curvature as possible. Similarly, a bottom surface portion 51E and the side portions 56A to 56C and the apex portions 55A to 55C are connected by a moderate curved surface with a small radius of curvature as viewed in the vertical section. It can be understood from the perspective view in
The body portion 51 and the cap portion 52 of the sample container 50 are preferably formed of a thermoplastic material such as polypropylene and polycarbonate, the body portion 51 can easily be formed by employing a blow molding process or an injection blow molding process. The cap portion 52 can easily be formed by employing an injection blow molding process. By using such a plastic material, there can be realized the sample container which has good chemical resistance and which is easy to be handled. In addition, rubber is suitable for a material of which the O-ring 57 is formed, and those commercially available can be used for the O-ring 57. The color of the body portion 51 may be transparent or colored so that the interior or contents cannot be seen from the outside.
Next, the shape of the rotor body 31 will be described by use of
The weight of the rotor body 31 can be reduced owing to a reduction in volume of a metal portion by reducing the thickness around the holding hole 32 because size of the holding hole 32 increases as a result of the increase in capacity of the sample container 50. Further, in the rotor body 31 of this embodiment, a concave portion (thickness reduced portion) 31G is formed by reducing the thickness of a central portion so as to gouge the portion downwards. This is because a centrifugal load exerted on the sample container 50 in the vicinity of the central portion is directed radially outwards and hence the holding of the container on the inner circumferential side is not so important (this centrifugal load will be described later by reference to
The rotor body 31 is an integral structure (a solid structure) which is formed through machining by use of an aluminum alloy material or a titanium alloy material. In addition, the rotor body 31 can also be formed of a CFRP composite material. In machining the rotor body 31 from such a metallic material, a milling machine is used, and an end mill is used as a blade, whereby the rotor body 31 can easily be worked. External dimensions of the rotor body 31 are limited by the size of the chamber 3 (refer to
Next, dimensions of the sample container 50 will be described by use of
When viewed from above, the sample container 50 is formed by the three curved surfaces with the radius of curvature R1 and the three curved surfaces with the radius of curvature R2. Connecting positions between the curved surfaces with the radius of curvature R1 and the curved surfaces with the radius of curvature R2 are indicated by triangular marks. In this way, the three sides (the side portions 56A, 56B, 56C) of the body portion 51 of the sample container 50 are formed by the large arc-shaped surfaces and the three apex portions 55A, 55B, 55C are formed into the small arc-shaped surfaces, whereby the sample container is made into the cylindrical container having the substantially regular triangular shape when it is seen from above or in cross section, thereby making it possible to realize a remarkable increase in capacity thereof. Although the three sides (the side portions 56A, 56B, 56C) of the sample container 50 may be formed not into the arc-like shape but into a straight line, by forming the three sides by the arc-shaped surfaces which swells outwards, the capacity of the sample container can be increased although slightly, and the resulting configuration becomes advantageous in terms of strength against inside pressure exerted from the sample contained in the interior thereof during the operation of the centrifuge.
In
The commercially available cylindrical sample container 250 (refer to
Next, the neck support member 70 will be described by use of
In the centrifuge, the rotor 30 rotates at high speeds. The outer circumferential portion of the cap portion 52 and the outer circumferential side wall portion 31D of the rotor body 31 is spaced apart from each other. Moreover, there is provided no portion to hold the outer circumferential side of the cap portion 52. Therefore, a portion lying in the vicinity of the opening portion 51A of the body portion 51 or the shoulder portion 51D may be damaged by the centrifugal load of the cap portion 52. In the case of the conventional cylindrical sample container 250 shown in
The neck support member 70 is shaped so that an external shape fits to the holding hole 32 in the rotor body 31 and a gap between the holding hole 32 and itself is approximately 0.1 to 1 mm. In addition, a lid insertion hole 70A, which is larger by approximately 0.1 to 1 mm than an outside diameter of the cap portion 52, is formed inside the neck support member 70. The thickness of the neck support member 70 is arbitrary, provided that the thickness is good enough to detachably support the cap portion 52, and the neck support member 70 does not have to be the same thickness thereover. In this embodiment, in consideration of the strength of the cap portion 52, the thickness of the neck support portion 70 is approximately half or 50% of the height (the thickness) of the cap portion 52.
The neck support member 70 is used so as to be placed on the shoulder portion 51D to surround the cap portion 52 from above the sample container 50 after the sample container 50 is attached in the rotor body 31. The neck support member 70 only has to be placed on the sample container 50. The neck support member 70 can prevent the cap portion 52 from being deformed in the direction of acting centrifugal force during centrifugal separation by employing in the way described above. Similar to the material of the body portion 50, the neck support member 70 can be formed of a thermoplastic material such as polypropylene or polycarbonate and can be formed easily through an injection molding process. However, the neck support member 70 is formed of a non-elastic material.
The neck support member 70 can attain its original object in case the neck support member 70 holds only almost half (an outer side) the outer circumferential side of the cap portion 52. However, in this embodiment, due to ease of fabrication, the neck support member 70 has almost the same shape of that of the sample container 50 and is configured so as to have apex portions 71A and side portions 71B. By adopting this configuration, the neck support member 70 can be attached in the holding hole 32 in the rotor body 31 in three circumferential positions, and therefore, the attachment thereof is facilitated. Note that the shape of the neck support member 70 does not have to be limited to the shape shown in
Thus, in the embodiment, the cross-sectional shape of the sample container 50 is made non-circular so as to increase the capacity thereof, and therefore, the weight of the rotor 30 in which the sample containers 50 are installed is increased. However, when comparing the increased amount of samples to be contained in the sample containers 50 with the reduced volume of the rotor 30 in mass, the increase in diameter and mass of the rotor can be suppressed compared with the conventional rotor body 131 having the same diameter as that of the rotor body 31 of the embodiment. This is because the excess portions lying around the sample containers can be reduced while increasing the amount of samples to be contained and the increased volume of samples can be accommodated in the excess portions.
Next, a centrifugal separating condition in the centrifuge 1 of the embodiment will be described by use of
When the rotor 30 rotates, the sample 60 is shifted to an outer circumferential side of the sample container 50 by virtue of centrifugal force as is shown in
A force is applied to the outer circumferential side of the sample container 50 so that the liquid is pushed out to an outside of the container. On the other hand, in the space 62, a load is applied in a direction in which the wall portion of the sample container 50 is pushed out to the outside by the centrifugal force. Normally, when the centrifugal load applied to the wall portion of the sample container 50 is increased, the sample container 50 fails in the worst case. In this embodiment, however, the portion of the sample container 50 to which the centrifugal load is applied is an inner circumferential side portion which is located in the vicinity of the apex portion, and this apex portion is made up of the curved surface with the small radius of curvature R1. Thus, at the apex portion, the rigidity is high and no edge is present and hence, no stress concentration occurs thereat, and the apex portion is has a strong resistance against centrifugal load. In addition, the opening portion 51A of the sample container 50 is circular and is, moreover, drawn inwards for attachment of the cap portion 52, and the shoulder portion 51D is formed. Consequently, in the sample container 50 of this embodiment, the rigidity of the portion where the space 62 which is the portion where load is particularly applied is present is increased to the high level. Therefore, the strength of the sample container 50 can be increased while increasing the capacity thereof, as a result of which the sample container 50 which has superior durability can be realized.
Next, a relationship between the shape of the horizontal section (the section taken along the portion indicated by the arrows A, A in
In the conventional sample container shown on the left-hand side, particles 72A which are positioned on an inner circumferential side of the sample container 250 move towards an outer circumferential side as the rotor rotates, pass through a position where particles 72B are present and then move to the outer circumferential side of the sample container 250 where particles 72C are present. On the other hand, a particle 73A positioned in the vicinity of a circumferential side surface of the sample container 250 similarly moves to a position where a particle 73B is present, collides against the wall of the sample container 250 and then moves as a particle 73C and a particle 73D do along the wall. In this way, the highly dense (heavy) particles contained in the sample move to the outer circumferential side to thereby be accumulated as a pellet 74.
In the sample container according to the embodiment shown on the right-hand side, particles 75A which are positioned on an inner circumferential side of the sample container 50 move towards an outer circumferential side as the rotor rotates, pass through a position where particles 75B are present and then move to the outer circumferential side of the sample container 50 where particles 75C are present. On the other hand, a particle 76A which is positioned in the vicinity of a circumferential side surface of the sample container 50 similarly moves to positions where particles 76B, 76C are present, respectively, collides against the wall of the sample container 50 and then moves along the wall as shown by a particle 76D. In this way, the highly dense (heavy) particles contained in the sample move to the outer circumferential side to thereby be accumulated as a pellet 77.
When both the sample containers are compared with each other here, the conventional sample container 250 has the circular wall, and therefore, the particles are collected to the center along the wall at the positions 73B to 73D. Thus, the particles have difficulty in moving due to friction with the wall, and hence the centrifugal separation needs to be carried out for a long period of time. On the other hand, when the sample container 50 is formed in the substantially triangular shape according to the embodiment, the degree at which the particle 76C collides against the wall is remarkably reduced. Even when there are particles which move along the wall, a distance over which the particles move along the wall is reduced, and therefore, the centrifugal separation may only have to be carried out for a short period of time. Thus, when the same samples are subjected to centrifugal separation, a good centrifugal separation effect is provided.
In many cases, the sample container 50 is caused to lie horizontally for removal of the pellet 77 settled in the container after the centrifugal operation has been completed.
Thus, as has been described heretofore, a large volume of sample can be processed at one time by use of the rotor 30 and the sample container 50 according to the embodiment. In addition, the sample container 50 of the embodiment is constructed so that the width increases from the inner circumferential side towards the outer circumferential side, and therefore, particles lying in the vicinity of the wall are allowed to reach the wall only after moving over a shorter distance. Thus, the possibility of the particles being influenced by the friction produced when they move along the wall surface can be reduced. Further, the external shape of the body portion 51 of the sample container 50 is not circular but substantially triangular, and therefore, there can be provided an advantage that the cap portion 52 is easy to be rotated when the operator attempts to rotate the cap portion 52 by one hand while gripping the body portion 51 by the other hand. In particular, after the centrifugal separating work has is completed, the rotor chamber 4 is cooled and hence the sample is also cooled in many cases, and hence, there may be caused such a situation that water collects as droplets on the sample container 50 removed. However, even in the event that the sample container 50 is wet, it is advantageous that the body portion 51 is made easy to be gripped by the three apex portions 55A, 55B, 55C.
The shape of the rotor which accommodates the sample container 50 according to the embodiment is not limited to the shape described above, and hence, other shapes can be adopted.
Next, a sample container 80 according to a second embodiment will be described. Although in the first embodiment the neck support members 70 which are the auxiliary members are used when the centrifugal separation is carried out, the neck support member 70 is the part which is prepared separately from the cap portion 52 and the body portion 51. Thus, there may be a possibility that the operator fails to mount the neck support members 70 and starts the operation of the centrifuge 1. Then, in the second embodiment, a cap portion and a neck support member are integrated with each other so that the failure to mount the neck support members 70 is prevented from occurring. As this occurs, however, when a screw type fastening approach is adopted in fastening a substantially triangular cap portion and a substantially triangular sample container together, a case can occur where there is caused a shift in position between a body portion of the sample container and the substantially triangular cap portion, and the substantially triangular external shapes of the cap portion and the body portion of the sample container do not match properly, resulting in a situation in which the sample container cannot be inserted into the holding hole in the rotor. In the event that the operator unscrews slightly the cap portion without any deep consideration to correct the matching error, there may be caused a risk that the sample leaks during centrifugal separation. Then, in the second embodiment, the cap portion is not screwed a single full rotation but is screwed less than the single full rotation, preferably, less than one third the single full rotation to be attached to the body portion of the sample container.
A cylindrical portion (which will be described later) is formed on a lower side of the outer lid 83 so as to correspond to the opening portion 81A of the body portion 81, and projecting portions (which will be described later) which make up the engaging unit are provided on an inner wall of the cylindrical portion. A female thread 83A is provided in a central portion of an upper surface of the outer lid 83 into which the push piece 85 is screwed. A hole 85A, which penetrates the push piece 85 in an axial direction, is provided to extend upwards from a lower surface of the push piece 85, and a projecting portion 84A on the inner lid 84 is accommodated in the hole 85A. An external shape of the push piece 85 is such that a grip portion 85B is formed on an outer circumferential portion of the push piece 85 so that the operator can screw it into the outer lid 83 with operator's hand. After the push piece 85 is attached to the outer lid 83, the projecting portion 84A of the inner lid 84 functions as a grip portion for attaching or removing the body portion 81 and the inner lid 84 to or from the body portion 81. When the push piece 85 is screwed in, a lower surface 85C of the push piece 85 presses down an upper surface 84B of the inner lid 84, and the O-ring 87, functioning as a sealing member between the body portion 81 and the inner lid 84, is compressed to thereby ensure a sealing performance of sample liquid. Incidentally, in place of the push piece 85 being shaped so that the grip portion 85B is formed so as project upwards largely from the outer lid, the push piece 85 may be shaped such that the push piece 85 does not project from the outer lid 83 so that the push piece 85 is screwed by using a tool.
The body portion 81 of the sample container 80 is made into a container having a cross-sectional shape (a shape resulting when viewed from above) based on a regular triangle in which side portions of the regular triangle are each formed into a curved surface with a large radius of curvature which is curved outwards moderately convexly and three apex portions of the regular triangle are each formed into a curved surface with a small radius of curvature. The shape and material of the body portion 81 of the sample container 80 are the same as those of the body portion 51 of the first embodiment excluding the shape of the engaging unit which include thick portions 90 and the groove portions 91, and hence, the repetition of the same description will be omitted here.
Next, the sample container 80 and the cap portion 82 will be described by reference to
In
The thick portions 90 are formed on the outer circumferential side of the opening portion 81A of the body portion 81, and portions where the thick portions 90 are not formed constitute the groove portions 91. On the other hand, the projecting portions 93 are formed at portions on an inner circumferential wall of the cylindrical shape of the outer lid 83, and the outer lid 83 is fixed in such a state that the projecting portions 93 enter the groove portions 91. Consequently, the thick portions 90 are located axially above the projecting portions 93. As this occurs, the O-ring 87 and the inner lid 84 are interposed between the opening portion 81A and the outer lid 83, and an upper surface 84B of the inner lid 84 is pressed downwards by the lower surface 85C of the push piece 85, whereby a good sealing performance can be obtained. To remove the cap portion 82 after the centrifugal separation is completed, firstly, the push piece 85 is unscrewed, and the lower surface 85C is shifted upwards so as to release the state in which the push piece 85 is pressed against the inner lid 84. Thereafter, the outer lid 83 is rotated. By following these steps, the outer lid 83 can be rotated smoothly, whereby the operator can easily remove the outer lid 83 by one hand. Thereafter, the operator grips on the projecting portion 84A to remove the inner lid 84.
On the other hand, a cylindrical inner wall 83E is formed in the outer lid 83, and a space 83D is formed above the inner circumferential wall 83E for accommodation of the O-ring 87 and an upper projecting portion of the inner lid 84. The projecting portions 93 are formed at three circumferential portions on the inner circumferential wall 83E (note that the projecting portion 93 shown in
Normally, a force moving the outer lid 83 in the direction of acting centrifugal force is generated in the outer lid 83 by a centrifugal force generated during centrifugal separation. Because of this, a large load is generated in the vicinity of the opening portion 81A, and in the worst case, the sample container 80 may be deformed or fail in the vicinity of the opening portion 81A. In this embodiment, however, the neck support portion 83C is formed on the outer lid 83, and the neck support portion 83C is brought into contact with the inner wall of the holding hole 132 in a good fashion. Thus, the outer lid 83 can be prevented from being shifted in the direction of acting centrifugal force, thereby making it possible to realize the sample container 80 which has superior durability.
Thus, as has been described heretofore, by employing the sample container 80 according to the second embodiment, a large amount of sample can be processed at one time. In addition, the external shape of the body portion 81 of the sample container 80 is formed into the substantially triangular shape. Thus, when the operator grips on the body portion 81 by one hand and turns the cap portion 82 by the other hand, there can be obtained an advantage that the cap portion 82 can easily be turned. Further, the neck support portion 83C having the same shape as the external shape of the body portion 81 is formed integrally on the cap portion 82. Therefore, the operator does not have to worry about the failure to attach the neck support member which is prepared as the separate member, and the deformation or failure of the cap portion 82 and the portion in the vicinity of the opening portion 81A of the body portion 81 by the centrifugal force can be prevented. In addition, even when the centrifugal force is applied thereto, the outer circumferential portion of the outer lid 83 matches the shape of the holding hole 132 of the rotor 130 and fits in the holding hole 132 with forming no gap therebetween, whereby the opening portion 81A and the cap portion 82 of the sample container 80 can be prevented from being deformed or damaged by the centrifugal force.
Next, a third embodiment will be described with reference to
A female thread 103A is provided in a central portion of an upper surface of the outer lid 103 into which the push piece 105 is screwed. A hole 105A, which penetrates the push piece 105 in an axial direction, is provided to extend upwards from a lower surface of the push piece 105, and a projecting portion 84A on the inner lid 84 is accommodated in the hole 105A so provided. A grip portion 105B is formed on an outer circumferential portion of the push piece 105 so that the operator can screw it into the outer lid 103 by the operator's hand. In the third embodiment, a number of vertical grooves are formed on the grip portion 105B so as to make it difficult for the hand of the operator to slip thereon. When the push piece 105 is screwed in, a lower surface 105C of the push piece 105 presses down an upper surface 84B of the inner lid 84, and the O-ring 87, functioning as the sealing member between the body portion 101 and the inner lid 84, is compressed to thereby ensure a sealing performance of the sample container 100. The body portion 101 of the sample container 100 has a cross-sectional shape (a shape resulting when viewed from above) which is a regular circle, and the material of the body portion 101 is the same as that of the body portion 51 of the first embodiment. Thus, the repetition of the same description will be omitted here.
According to the third embodiment that has been described above, in the cylindrical sample container having the same external shape as that of the conventional example, the engaging type opening and closing structure is adopted for the cap portion 102. Thus, when attaching the cap portion 102 on the body portion 101, the cap portion 102 is pushed axially relative to the body portion 101 and is then turned through about 60 degrees in a clockwise direction as viewed from above, whereby the cap portion 102 can easily be fastened on to the body portion 101. In addition, when removing it from the body portion 101, the cap portion 102 only has to be turned through about 60 degrees in a counterclockwise direction. Thus, the cap portion 102 can easily be attached to and detached from the body portion 101. Moreover, the closeness is increased by pressing the inner lid 84 by employing the push piece 105, and therefore, the leakage of sample during centrifugal operation can be prevented.
Thus, while the aspect of the invention has been described based on the embodiments, the invention is not limited to the embodiments that have been described and hence can be modified variously without departing from the spirit and scope of the invention. For example, while the rotor is formed through monolithic molding, a type of rotor which is formed separately or a swing rotor may be adopted. In addition, the shape of the sample container as viewed from above is not limited to the substantially regular triangular shape, and hence, a substantially isosceles triangular shape may be adopted.
| Number | Date | Country | Kind |
|---|---|---|---|
| P2010-145724 | Jun 2010 | JP | national |
