Centrifuge with drainage

Abstract

A centrifuge for cleaning a reaction vessel unit comprises a rotor and a rotor chamber in which the rotor is positioned and supported in rotary fashion. The rotor chamber is delimited by a housing having a drainage channel beneath the rotor. Adjacent to the channel, the inner surface of the housing is embodied in the form of a funnel that feeds into the channel. This centrifuge does not require a suction pump for suctioning liquids from the rotor chamber. In addition, the centrifuge can be provided with an exchangeable module that delimits the rotor chamber and includes the rotor. The exchangeable module can be exchanged after a predetermined amount of use and replaced with another. It is also possible, however, for the module to be removed from the centrifuge, cleaned, and reinserted.

Claims

1. A centrifuge for cleaning a reaction vessel unit, comprising a rotor and a rotor chamber in which the rotor is positioned and supported in rotary fashion, wherein the rotor has a receiving region for receiving the reaction vessel unit and the rotor chamber is delimited by a housing having a drainage channel beneath the rotor and, adjacent to the drainage channel, the inner surfaces of the housing form a funnel that feeds into the drainage channel, wherein the drainage channel is based apart in the downward direction from a funnel-shaped lower shell, wherein the distance of the drainage channel from a rotation axis around which the rotor rotates is at least 1.1 times the radius of the rotor, the housing is comprised of a lower and an upper shell, wherein the upper shell has a cross-sectionally semicircular shape, a loading and unloading device is provided, which includes a rigid displacing rod for positioning the reaction vessel unit in the rotor or for removing the reaction vessel unit from the rotor, wherein the displacing rod is positioned in a movable fashion in such a way that it is movable between an unloading position, in which it extends through the rotor in the rotor chamber, and a loading position, in which it is retracted at least from the region of the rotor chamber that is occupied by the rotor during a rotation, and a linear drive for moving the displacing rod between the unloading position and the loading position, and the inner surface of the housing, at least in the region of the funnel and the drainage channel, is coated with a hydrophobic layer.

2. The centrifuge according to claim 1, wherein the hydrophobic layer is composed of PTFE.

3. The centrifuge according to claim 1, wherein the rotation axis of the rotor extends parallel to a support surface of the housing.

4. The centrifuge according to claim 1, wherein the drainage channel is inclined relative to a support surface of the housing.

5. The centrifuge according to claim 1, wherein the housing has a ventilation opening, which has an air filter positioned in it.

6. The centrifuge according to claim 1, wherein the drainage channel has at least one approximately vertically positioned side wall.

7. The centrifuge according to claim 1, comprising a drive unit for rotating the rotor, wherein the centrifuge has an exchangeable module that comprises the rotor and a housing section of the housing, said housing section enclosing the rotor, and the exchangeable module is embodied so that it is detachable from the other parts of the centrifuge.

8. The centrifuge according to claim 1, wherein at a free end of the displacing rod positioned in the rotor chamber, a coupling element is provided; the coupling element serves to produce a reconnectable connection of the displacing rod to the reaction vessel unit or to a supporting device for the reaction vessel unit.

9. The centrifuge according to claim 8, wherein the coupling element has a detent element, which can engage with a counterpart detent element provided on the reaction vessel unit or the supporting device, with at least the detent element or the counterpart detent element being elastically supported.

10. The centrifuge according to claim 1, wherein the displacing rod is hollow and is embodied as open at the hack end oriented away from the rotor chamber, a threaded rod is provided coaxial to the displacing rod, and the threaded rod engages in meshing fashion with a thread connected to the displacing rod so that a rotating motion of the threaded rod causes a translatory motion of the displacing rod to be executed; the threaded rod can plunge into the back end of the displacing rod.

11. The centrifuge according to claim 1, wherein a detection device for determining the position of the displacing rod in the movement direction is provided.

12. The centrifuge according to claim 1, further comprising a pipetting unit, the pipetting unit having a plurality of pipetting nozzles.

13. The centrifuge according to claim 1, further comprising an optical detection unit, the optical detection unit being embodied and positioned in such a way that adjacent to the rotor chamber, the optical detection unit is able to scan the reaction vessel unit within the reaction vessel unit's movement range.

14. The centrifuge according to claim 13, wherein the optical detection unit includes a line scan camera in order to perform a line scan of the reaction vessel unit, with a scan line being oriented approximately perpendicular to the movement direction of the reaction vessel unit.

15. The centrifuge according to claim 13, wherein the centrifuge has an evaluation device with which the signals received with the optical detection unit are automatically evaluated according to the following parameters: color of the contents of at least one reaction vessel of the reaction vessel unit, fill level of at least one reaction vessel of the reaction vessel unit, position of the reaction vessel unit, type of reaction vessel unit.

16. The centrifuge according to claim 1, wherein the reaction vessel unit is positioned in the rotor with openings of the reaction vessels oriented radially outward, together with the reaction vessel unit, the rotor is rotated around the rotation axis so that the contents of the reaction vessels are centrifuged out and, solely due to the rotary motion of the rotor and the force of gravity, are driven into the drainage channel and from there toward the outside.

17. The centrifuge according to claim 1, wherein the reaction vessel unit is positioned in the rotor with openings of the reaction vessels oriented radially outward, the rotor is rotated together with the reaction vessel unit around the rotation axis so that the contents of the reaction vessels are centrifuged out; and alter the cleaning of one or more reaction vessel units, an exchangeable module that includes a housing section and the rotor is separated from the remaining part of the centrifuge and is either cleaned or replaced with another exchangeable module.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) In the drawings:

(2) FIG. 1 shows a perspective view of a part of a housing of a centrifuge,

(3) FIG. 2 shows an oblique front sectional view of the part of the housing from FIG. 1,

(4) FIG. 3 shows a longitudinal section through the part of the housing from FIG. 1,

(5) FIG. 4 shows a longitudinal section through parts of a centrifuge with the housing part from FIG. 1,

(6) FIG. 5 schematically depicts another exemplary embodiment of a centrifuge with an exchangeable module, and

(7) FIG. 6 schematically depicts a longitudinal section through another exemplary embodiment of a centrifuge with an exchangeable module.

DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

(8) A centrifuge 1 according to the invention (FIG. 4) has a rotor 2, a housing 3, and a drive unit 4 for rotating the rotor 2 around a rotation axis 5.

(9) The rotor has at least one receiving region 6 for receiving a reaction vessel unit 7. The reaction vessel unit 7 is usually a microtiter plate. Such microtiter plates can be embodied with a different number of reaction vessels. It is typical for microtiter plates to have from 6 to 4096 reaction vessels; microtiter plates with 96, 384, or 1536 reaction vessels are the most common versions. In microtiter plates with 384 or 1536 reaction vessels, the individual reaction vessels are so thin that a liquid normally adheres to the inside of them based solely on capillary forces so that even when such a microtiter plate is placed with its openings facing downward, the liquid does not drain out. For microtiter plates with fewer reaction vessels, each of which is larger, this is not the case. Such a reaction vessel unit 7 can only be inserted into a receiving device 6 or placed on a supporting device. Preferably, a supporting device is used, which has a coupling element that can be coupled to a loading and unloading device 8. Such a loading and unloading device is described, for example, in DE 10 2016 101 163. It is explained in greater detail below.

(10) The housing 3 delimits a rotor chamber 9. In the present exemplary embodiment, the region of the housing 3 delimiting the rotor chamber 9 is composed of a lower shell 10, upper shell 11, front end wall 12, and back end wall 13. The back end wall is adjoined by other parts of the housing, which are not shown in the attached figures.

(11) The front end wall 12 and back end wall 13 each have a ball bearing 14 in which a continuous shaft 15 of the rotor 2 is supported in rotary fashion. The center line of the shaft 15 constitutes the rotation axis 5. The rotation axis 5 extends parallel to a support surface 16, which is embodied by the underside of the lower shell 10.

(12) The back end of the shaft 15 is coupled to the drive unit 4. The other part of the housing, which adjoins the back of the housing, contains the drive unit 17, the loading and unloading device 8, and a central control unit (not shown), which controls all of the components of the centrifuge 1.

(13) At the front end wall 12, a ledge 18 is mounted on the outside, which is for accommodating a reaction vessel unit 7. At the level of the ledge 18, the front end wall 12 is provided with a loading and unloading opening 19 through which a reaction vessel unit 7 is inserted into the rotor chamber 9 and can be slid back out again. The loading and unloading opening 19 is provided with a pivoting door 20 so that the rotor chamber can be closed.

(14) Adjacent to this door 20, a dispenser unit can be provided, which has a plurality of dispenser nozzles and/or an optical detection unit, particularly in the form of a line scan camera.

(15) The loading and unloading device 8 has a displacing rod (not shown), which can be moved with its free end horizontally through the rotor chamber 9 through opening 21 in the back end wall 13. For this purpose, the loading and unloading device 8 has a linear drive unit so that the displacing rod can be moved in linear fashion along its longitudinal direction. The free end of the displacing rod has a coupling element, which can be coupled to an appropriate coupling element on the supporting device or a reaction vessel unit 7 so that the supporting device can be moved with a reaction vessel unit or the reaction vessel unit directly by moving the displacing rod from the ledge 18 through the loading and unloading opening 19 and into the rotor chamber 9, in this case, the rotor 2 being positioned with a receiving region 6 adjacent to the loading and unloading opening 19 so that the supporting device or the reaction vessel unit is slid into the receiving region 6 of the rotor 2. The coupling between the displacing rod and the supporting device or reaction vessel unit 7 can be detached so that the supporting device or reaction vessel unit is able to move freely in the rotor 2 and the rotor can be correspondingly rotated with this unit.

(16) By means of the displacing rod of the loading and unloading device 8, the supporting device or reaction vessel unit 7 can be slid out of the receiving region 6 of the rotor 2 by means of the loading and unloading opening 19 and back onto the ledge 18. On the ledge 18, the reaction vessel unit 7 can be removed, for example by means of a robot.

(17) The lower shell 10 has a channel 22, which extends approximately parallel to the rotation axis 5. The channel 22 extends from the back end wall 13 into the region of the front end wall 12 and is embodied as inclined or descending toward the front (FIG. 4). On the front of the lower shell 10, an outlet opening 23 is provided, into which the channel 22 feeds. The outlet opening 23 has a connection fitting 24 to which a hose 25 can be connected. The hose 25 generally feeds into a receiving container (not shown), which receives the liquids that are centrifuged out of the reaction vessels of the reaction vessel unit 7 in the centrifuge 1. The container preferably has a ventilation opening or the hose extends through the container with a small amount of play so that liquid traveling out of the centrifuge through the hose 25 does not generate any back pressure in the container.

(18) Adjacent to the channel 22, the lower shell 10 has inner surfaces, which each extend from an upper edge of the channel 22, each rising in an inclined fashion toward the outside (FIG. 2). These inner surfaces therefore form a funnel 26 and are referred to below as funnel surfaces 27. The funnel surfaces 27 are inclined at an angle of approximately 30° to 60° relative to the horizontal. Essentially, “planar” means that the funnel surfaces have a curvature radius of greater than 0.5 m and preferably greater than 1 m. In the present exemplary embodiment, the funnel surfaces 27 extend laterally in a direction beyond the region of the rotor 2, even if the latter is in its horizontal position.

(19) From the outer edge of the funnel 26 or the funnel surfaces 27, the inner surfaces of the lower shell 10 extend upward approximately vertically. They therefore form vertical surfaces 28.

(20) The upper shell 11 is fastened to the upper edge of the lower shell 10 and has a trough-shaped, cross-sectionally semicircular shape. The inner surface of the upper shell 11 transitions flush into the vertical surface 28. The cross-section of the housing 3 is thus not cylindrical, as is known from the prior art, instead having a cylindrical curvature only in the upper region of the shell 11, whereas the lower shell 10 tapers in a funnel shape cross-sectionally and ends at the channel 22. The channel 22 is spaced apart somewhat in the downward direction from the funnel-shaped lower shell 10 and has two approximately vertically oriented side walls 37a, 37b. The channel itself is embodied with an inclination so that a liquid contained therein drains out.

(21) In the present exemplary embodiment, the lower shell 10 and the upper shell 11 are composed of metal. The inner surfaces of the lower shell 10 and upper shell 11 are coated with a smooth plastic layer so that liquids, which are centrifuged out of the reaction vessels of the reaction vessel units 7, drain out quickly along the inner surfaces, are conveyed by the funnel 26 to the channel 22, and from there, drain out of the rotor chamber 9. The plastic layer is composed of PTFE.

(22) The upper edge of the channel 22 is spaced apart from the rotation axis 5 by at least 1.2 times the maximum radius of the rotor 2. This forms a free space in the funnel 26, which is not touched by the rotor 2 as it rotates. Liquid can collect in this free space. FIG. 2 shows a maximum level 29 of the liquid, which can collect in the funnel 26 without coming into contact with the rotor. It is therefore possible, with high-volume reaction vessels of a reaction vessel unit 7, to empty most of the liquid contained therein all at once and to collect it in the funnel 26 so that it can drain out gradually through the outlet opening 23.

(23) In addition, because of the large distance of the channel 22 from the rotor and the resulting large cross-section, an air flow generated by the rotor in this region is minimal so that liquid can settle at the bottom of the funnel, i.e. in the channel 22, and drains out of the channel 22 through the outlet opening 23. Because of the low flow speed there is also a low risk of liquids, which are in the funnel-shaped region adjacent to the channel 22, being driven upward by the air flow.

(24) Since the channel is delimited by approximately vertical side walls 37a, 37b, even when an air flow is produced in the rotation direction 38, this can no longer drive the liquid out of the channel. Once a liquid has been captured in the channel 22, it can only exit through the outlet opening 23. In the exemplary embodiment shown in FIG. 2, an air flow can strike the side wall 37a, which is positioned downstream in the rotation direction 38 of the rotor in the channel 22. But since the side wall 37a is approximately perpendicular to the flow direction, the liquid in the channel can no longer be driven back into the rotor chamber. Basically, it is sufficient for there to be a channel with an approximately vertical side wall on the side of the channel 22 positioned downstream in the rotation direction 38. For production-related reasons, however, it is advantageous to produce a channel with two approximately vertical side walls 37a, 37b.

(25) Through this embodiment of the funnel 26 and channel 22, it is unnecessary to use a suction pump of the kind that is known form the prior art.

(26) Another exemplary embodiment of a centrifuge is explained below, which is depicted in a very schematically simplified way in FIG. 5. Unless otherwise stated below, this exemplary embodiment is embodied identically to the exemplary embodiment explained above. For this reason, the same reference numerals have been used for parts that remain unchanged.

(27) The centrifuge 1 once again has a housing 3 with a rotor 2, a drive unit 4, a ledge 18, a loading and unloading device 8, and a central control unit 30. A rotor chamber 17 is covered at the top by a pivoting cover 31. The pivoting cover 31 is connected by means of a pivot joint to the remaining part of the housing 3, specifically in the region of the back end wall 13. Once again, the rotor 2 is supported in the rotor chamber 9, but in this embodiment, it is a component of an exchangeable module 32. The exchangeable module 32 has an exchangeable module housing 33, which encloses the rotor 2 essentially completely and fits into the rotor chamber 17 of the housing 3 with a small amount of play. The exchangeable module housing 33 has a front end wall 12a, a back end wall 13a, a lower shell 10a, and an upper shell 11a. These walls 12a, 13a, or shells 10a, 11a are thin walls, which preferably constitute inner surfaces, which correspond to the shape of the inner surfaces of the rotor chamber 9 of the above-explained first exemplary embodiment.

(28) With the cover 31 open, the exchangeable module 33 can be removed from the housing 3 in the vertical direction 34 and replaced by another exchangeable module 33 or cleaned and then reused. When opening the cover 31, the loading and unloading device 8 and the drive unit 4 are each moved slightly away from the rotor chamber 17 in the horizontal direction. This retracts the free end of the displacing rod of the loading and unloading device 8 and a shaft journal of the drive unit 4 from the rotor chamber 17 so that they are not an obstacle to a movement of the exchangeable module housing 33 in an upward direction. When the pivoting cover 31 is closed, the loading and unloading device 8 and the drive unit 4 are slid back horizontally in the direction of arrow 34.

(29) If an exchangeable module is present in the housing 33 in the rotor chamber 17, then as a result of this, the shaft journal of the drive unit 4 is coupled to the shaft of the rotor 2 and the free end of the displacing rod into a corresponding through opening of the exchangeable module housing 33. As a result, the exchangeable module housing 33 is automatically coupled into the housing 3 and is connected to the corresponding functional parts.

(30) At the lower edge, the exchangeable module housing 33 once again has a channel 22, which feeds into an outlet opening 23 of the housing 3.

(31) FIG. 6 has a variant of the second embodiment, which, instead of a pivotable cover 31 for limiting the rotor chamber 17, has a removable hood 35, which has the front end wall 12 and a covering wall 36 that delimits the rotor chamber 17 at the top. This hood 35 can be removed in the horizontal direction (arrow 34) so that the exchangeable module housing 33 is exposed. The exchangeable module housing 33 can be removed from the remaining part of the housing 3 in the horizontal direction (arrow 34). In this case, there is no mechanism provided for moving the drive unit 4 or the loading and unloading device 8.

(32) When the housing 3 is open, the exchangeable module housing 33 can be exchanged or removed for cleaning and can be reinserted.

(33) If the exchangeable module housing 33 is cleaned for example by means of autoclaving, then it is advantageous for it to be composed of heat-resistant materials such as metal. It can also be advantageous, however, to completely replace the exchangeable module after a certain amount of use. On the one hand, the reaction vessel units can be cleaned of substances that attack and for example corrode the exchangeable module 32. It is then advantageous to completely replace the exchangeable module 32 after a predetermined operating time of a few weeks to a few months. If such exchangeable modules 32 are used as consumables, then it can also be advantageous for them to be essentially composed of plastic. The exchangeable module housing 33 is preferably composed of a material with a high chemical resistance such as PTFE. The rotor is preferably composed of a hard plastic material, in particular in the form of an injection-molded part.

(34) Both the hood 35 and the pivoting cover 31 can be fastened to the rest of the housing 3 by means of a detent or snap mechanism.

(35) TABLE-US-00001 Reference Numeral List  1 centrifuge  2 rotor  3 housing  4 drive unit  5 rotation axis  6 receiving region  7 reaction vessel unit  8 loading and unloading device  9 rotor chamber 10 lower shell 10a lower shell 11 upper shell 11a upper shell 12 front end wall 12a front end wall 13 back end wall 13a back end wall 14 ball bearing 15 shaft 16 support surface 17 rotor chamber 18 ledge 19 loading and unloading opening 20 door 21 through opening 22 channel 23 outlet opening 24 connection fitting 25 hose 26 funnel 27 funnel surface 28 vertical surface 29 level 30 central control unit 31 pivoting cover 32 exchangeable module 33 exchangeable module housing 34 arrow 35 hood 36 covering wall 37a side wall 37b side wall 38 rotation direction