Multichannel pipetting system comprising two aspiration chambers that are imbricated in one another

Abstract

The invention relates to a device (32) for the bottom part of a multichannel pipetting system, comprising two sampling-cone-holding end pieces (6) and also two aspiration chambers (36a, 36b) that engage respectively with the two end pieces, the two aspiration chambers (36a, 36b) being concentric.

Claims

1. A multichannel pipetting system comprising: a bottom part comprising a plurality of devices, each said device comprising two concentric aspiration chambers; and two end pieces arranged side-by-side and respectively fluidly connected to said two aspiration chambers, wherein one of said two aspiration chambers is concentrically arranged with respect to the other of the two aspiration chambers, wherein each said end piece comprises a through port fluidly connected to one of said two aspiration chambers, and wherein said plurality of devices are arranged such that a center axis of each said end piece intercepts a same straight line, thereby forming a row of said end pieces.

2. The multichannel pipetting system according to claim 1, wherein each of the plurality of devices further comprises two pistons each respectively located in one of said two aspiration chambers, wherein a first of said two pistons has a cylindrical shape and a second of said two pistons has a ring-shape horizontal cross-section in a top plan view.

3. The multichannel pipetting system according to claim 2, wherein said two pistons are each slidable in each of the respective two aspiration chambers in a longitudinal direction that is the same as a center axis of said bottom part.

4. The multichannel pipetting system according to claim 1, wherein a first of said two aspiration chambers has a solid circle-shaped horizontal cross-section in a top plan view, and a second of said two aspiration chambers has an annular-shaped horizontal cross-section in the top plan view.

5. The multichannel pipetting system according to claim 4, wherein the device further comprises two pistons each respectively located in one of said two aspiration chambers, wherein a first one of said two pistons has a cylinder shape and a second one of said two pistons has a ring-shaped horizontal cross-section in the top plan view, wherein said cylinder-shaped piston is located in the first aspiration chamber, wherein said first aspiration chamber comprises a closed end which forms a seal, and wherein said closed end of said first aspiration chamber also forms said first piston.

6. The multichannel pipetting system according to claim 1, wherein a center axis of each said end piece is spaced apart from the other adjacent end piece with a pitch of 9 mm.

7. The multichannel pipetting system according to claim 1, wherein said two aspiration chambers each have an identical horizontal cross-section surface area in a top plan view.

8. The multichannel pipetting system according to claim 1, wherein at least one of said two aspiration chambers of one of said plurality of devices has a different surface area in a horizontal cross-section in a plan view from a surface area of at least one of said two aspiration chambers of at least one other of said plurality of devices of the bottom part.

9. The multichannel pipetting system according to claim 1, wherein said multichannel pipetting system further comprises a handle body which forms an upper part connected to said bottom part.

10. The multichannel pipetting system according to claim 1, wherein said through port of each end piece is off-center in a top plan view with respect to a center axis of a horizontal cross-section of each respective end piece.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) This description will be made in view of the appended drawings from which:

(2) FIG. 1 represents a front view of an air displacement multichannel sampling pipette, according to a preferred embodiment of the invention;

(3) FIG. 2 represents a partial enlarged view of the bottom part of the pipette shown in the previous figure;

(4) FIG. 3 represents an enlarged longitudinal cross-section view of a device specific to the invention, equipping the bottom part of the pipette, said device having the form of a first preferred embodiment of the invention;

(5) FIG. 4 is a cross-section view taken along line IV-IV of FIG. 3;

(6) FIG. 5 is a perspective exploded view of the device shown in FIGS. 3 and 4;

(7) FIG. 6 represents a perspective view of the fixed part of the device shown in FIGS. 3 to 5, according to another view angle;

(8) FIG. 7 represents a cross-section view taken along line VII-VII of FIG. 2;

(9) FIG. 8 represents a view similar to that of FIG. 3, with the device having the form of a second preferred embodiment of the invention;

(10) FIG. 9 is a cross-section view taken along line IX-IX of FIG. 8; and

(11) FIG. 10 is a perspective exploded view of the device shown in FIGS. 8 and 9.

DETAILED DISCLOSURE OF PREFERRED EMBODIMENTS

(12) In reference first to FIG. 1, a multichannel sampling pipette 1 is represented according to a preferred embodiment of the present invention. However, the invention is not limited to pipettes, but is applicable to any multichannel pipetting system, and in particular to automated pipetting systems, called automatons.

(13) The manual or motorised air displacement pipette 1 comprises at the upper part, a handle body 2, as well as a bottom part 4 also object of the present invention, integrating at the lower end thereof, pipette-sampling-cone-holder end pieces 6, on which cones or consumables 8 are intended to be fitted.

(14) The sampling-cone-holder end pieces 6 are spaced apart from each other, along a lateral direction of the pipetting system, or even pipette lateral direction, represented by the arrow 10. Each end piece 6 has a through port 12 communicating at the upper end thereof with an aspiration chamber (not visible in FIG. 1), and at the lower end thereof, with a sampling cone 8. The through port 12 is centred or not on its associated end piece 6, that is it is centred or not on a centre axis 7 of the end piece on which the fitted cone is centred.

(15) The pipette 1 has a longitudinal centre axis 14, also corresponding to a longitudinal centre axis of the bottom part 4. This axis 14 is orthogonal to the lateral direction 10, and usually placed so as to have an identical number of end pieces 6 disposed on either side of the same, in the lateral direction. Further, generally, the axis 14 is parallel to the axes of the through ports 12 and to the axes 7 of their associated cones 8, and also parallel to a sliding direction of the movable elements of the pipette bottom part 4, which will be described hereinafter.

(16) In the example shown in FIG. 1, there are eight end pieces 6 aligned along the direction 10, so as to form a row. Thus, the centre axis 7 of each end piece 6 intercepts a same straight line 9 extending along the direction 10.

(17) As is known to those skilled in the art, the bottom part 4 is preferentially screwedly mounted on the handle body 2.

(18) One of the features of the invention is in the design of the bottom part 4, which will be first detailed in reference to FIGS. 2 to 7 representing a first preferred embodiment.

(19) In a known manner, the bottom part 4 comprises a fixed body 16, as well as an assembly movable with respect to this fixed body, along a sliding direction 18 parallel to the axis 14 and orthogonal to the lateral direction 10. The movable assembly first has a plurality of pistons 20a, 20b parallel to the direction 18, and each associated with an end piece 6.

(20) The movable assembly also has a piston-holder 22 located overall above the pistons 20a, 20b, this piston-holder comprising a guide rod 24 centred on the axis 14, as well as a piston supporting head 26 integral with the bottom part of the rod 24. The head 26, arranged in parallel to the lateral direction 10, thus orthogonal to the sliding 20 direction 18 as well as to the axis 14, takes the form of a rack accommodating a connector 31 at an upper end of the pistons between its teeth. More precisely, the upper ends of the piston are translationally blocked by the rack in both sliding directions 18, in order to be able to follow the reciprocating movement of the piston-holder along this same direction.

(21) The fixed body 16 of the pipette bottom part is made using several elements integral with each other, added or made as a single piece. This is first a guide cylinder 28 centred on the axis 14 and slidingly accommodating the rod 24 of the movable piston-holder. In addition, a structure 30 arranged below the cylinder 28 is provided to delimit a sliding space of the supporting head 26, this structure being substantially oriented along a plane parallel to the directions 10 and 18. As is shown in FIG. 1, an external removable cap 17 completes the fixed body 16, this cap covering the structure 30 and the devices 32 which will be described below overall, such that only a lower part of the end pieces 6 is projecting outside this cap.

(22) The bottom part 4 indeed includes a plurality of individual devices 32, specific to the present invention. These are four devices aligned along the straight line 9. Each of these devices 32 defines two end pieces 6, also deviated from each other along the straight line 9 and the direction 10. The fixed parts of these devices 32 can be independent from each other and added on the fixed body 16 of the bottom part, or even made as a single piece added on this same fixed part. Both end pieces 6 are added to the other fixed parts of the device 32.

(23) Each device 32 defines with the upper fixed portion thereof two concentric aspiration chambers 36a, 36b, the internal chamber 36a being surrounded by the external chamber 36b. In this regard, it is noted that both imbricated aspiration chambers 36a, 36b cover axially each other on at least one axial portion thereof, but not necessarily on their entire axial lengths.

(24) The internal aspiration chamber 36a, or first chamber, has a substantially disc shaped transverse cross-section, whereas the external aspiration chamber 36b, or second chamber 36b, has a substantially annular shaped transverse cross-section. In transverse cross-sections, both chambers 36a, 36b have identical surface areas to obtain a same sampling volume, or different surface areas in order to perform multivolume samplings. In this regard, it is indicated that this possibility of different volumes is possible between both chambers of a same device 32, but also between various devices. For this, it is provided that at least one of the aspiration chambers 36a, 36b of one of the devices 32 has a different surface area from that of at least one of the aspiration chambers 36a, 36b of at least one other device 32 of the bottom part.

(25) Each chamber 36a, 36b slidingly accommodates a piston 20a, 20b, respectively. Thus, the device 32 includes two pistons 20a, 20b having complementary shapes to those of their respective chambers, such that the internal piston 20a takes the form of a cylinder, and the external piston 20b that of a ring. Both pistons 20a, 20b are preferably made as a single piece, and attached to the rack 26 by the same mechanical connector 31, preferably integrated to the single piece part. Both pistons 20a, 20b are thus imbricated in one another.

(26) The sealing of both chambers 36a, 36b is for example achieved by placing an O-ring 37 at the distal end of the second piston 20b, facing the bottom of the aspiration chamber 36b. It is precisely at this chamber bottom that is provided a port 13b allowing the air communication with the port 12 of the end piece, and thus allowing the air communication with the cone 8. The same is true for the bottom of the internal chamber 36a, by virtue of making a port 13a.

(27) By concentrically arranging the aspiration chambers 36a, 36b, as well as the associated pistons, it is possible to reduce the overall space of the bottom part, and to respect a suitable pitch 40 between the centre axes of the end pieces. This pitch 40 can not only be met between both end pieces 6 of a same device 32, but also between the end pieces 6 facing each other two by two, belonging to adjacent devices. The top part of the devices 32 has indeed a lateral overall space, along the direction 10, which is lower than the cumulative overall space of both end pieces 6. By way of indicating example, with a pitch 40 set to 9 mm, each chamber 36a, 36b can has a cross-section area in the order of 75 mm.sup.2, with a piston pipetting stroke set to 16 mm. This enables liquid samples with a high volume to be sampled, while having a reduced overall space and a satisfactory ergonomics. In particular, the external diameter of the chamber 36b can be substantially lower than twice the value of the pitch 40 of 9 mm, since it is in the order of 14.6 mm.

(28) In a known manner, the guide rod 24 of the piston-holder 22 is driven by a manual or motorised equipment imposing it a raising stroke during liquid sampling phases, and a lowering stroke during liquid transfer phases. The raising stroke is generally made in a manual mode, under the expansion effect of a previously compressed spring during the previous lowering stroke. During its movement, the piston-holder 22 drives together with it the pistons 20a, 20b integral with the rack 26, such that the latter are consequently capable of being simultaneously moved along the sliding direction 18. The raising stroke imposed to the assembly movable with respect to the fixed body 16 determines the liquid volume sampled, which volume is precisely previously set by the user, by means for example of a knob, a set screw or even a numeric keypad.

(29) In reference now to FIGS. 8 to 10, is represented a device 32 according to a second preferred embodiment of the invention, which is characterised by a simplified manufacture. The second embodiment has numerous similarities with the first embodiment described above. Thus, in the figure, elements having the same reference numerals correspond to identical or similar elements.

(30) In this second preferred embodiment, the main difference with the first embodiment lies in the design of the first piston 20a.

(31) Indeed, the second piston 20b remains identical to that previously described, by being accommodated in the chamber 36b the transverse cross-section of which is substantially annular shaped, by being defined between an internal body 50 and an external body 52 of the upper fixed part of this device 32. The internal body 50 is cylindrical with a disc-shaped cross-section, whereas the external body 52, arranged around and remotely from the internal body 50 has a substantially annular transverse cross-section.

(32) The second piston 20b accommodated in the second chamber 36b thus maintains its general ring shape, sealed at the top axial end thereof by a seal. One of the features of this second embodiment lies in the fact that this seal, being disc-shaped and arranged substantially orthogonal to the axes 7, makes up the first piston 20a.

(33) Both pistons 20a, 20b thus remain concentric, while being placed one 20 above the other. With this arrangement, the first aspiration chamber 36a is axially delimited between the top end of the first piston 20a which provides the seal and the top axial end 50 of the internal body 50, and laterally delimited by the internal surface of the second piston 20b. In operation, the lateral wall of the second chamber 36b thus has the feature to be movable, because it consists of the second piston 20b. Both chambers 36a, 36b remain concentric also, while being arranged one above the other.

(34) The internal body 50 is pierced with a port 13a which opens into the bottom of the chamber 36a, at the top axial end 50. It extends, in a centred way or not, through the entire internal body 50, to open into the port 12 of the associated end piece 6. In the same way, the port 13b ensures air communication between the annular chamber 36b and the port 12 of the associated end piece 6.

(35) Of course, various modifications can be made by those skilled in the art to the invention just described, only by way of non-limiting examples.