WO2010057629A2

WO2010057629A2 - Ultrasonic sensor and device for registering levels in micro titer plates

Info

Publication number: WO2010057629A2
Application number: PCT/EP2009/008221
Authority: WO
Inventors: Rainer Mauch; Thomas Röhm; Michael Haas
Original assignee: Baumer Innotec Ag
Priority date: 2008-11-18
Filing date: 2009-11-18
Publication date: 2010-05-27

Abstract

The invention relates to an ultrasonic sensor (1) comprising a rectangular housing (3), in which at least one of the side lengths is smaller than the grid dimension s of cavities (17) in micro titer plates (15). The housings (3) comprise contact surfaces and positioning and holding means for simple fastening to assembly plates (29). A plurality of ultrasonic sensors (1) can be fastened in a fixed position relative to one another such that the distances to neighboring ultrasonic converters (11) correspond to the grid dimension s of the cavities (17) or a whole-numbered multiple thereof.

Description

Ultrasonic sensor and device for detecting fill levels in microtiter plates

The invention relates to an ultrasonic sensor and a device for detecting levels in cavities of microtiter plates according to the features of the preambles of claims 1 and 11.

Microtiter plates are usually rectangular plates with many mutually isolated cavities or wells, which are arranged in a grid or in rows and columns. They are usually made of plastic, sometimes made of glass and are widely used in the pharmaceutical industry e.g. used for recording and analyzing biological samples. Microtiter plates are available in a variety of formats with different vessel heights and / or number of vessels. According to the ANSI standard, the dimensions of the microtiter plates are standardized: length L = 127.76 mm, width B = 85.48 mm and height H = 14.35 mm. Plates with 6 wells (2 x 3) are available for filling volumes of 2-5 ml, 12 wells {3 x 4) for filling volumes of 2 - 4 ml, 24 wells (4 x 6) for filling volumes of 0.5 - 3 ml and 96 wells (8 x 12) for filling volumes of 0.3 - 2 ml.

During sample processing, it is often necessary to determine the fill levels in the individual vessels with sufficiently high accuracy. For this purpose ultrasonic sensors can be used which operate according to the pulse-echo method. An ultrasonic transducer sends Ultrasonic bursts in one of the vessels from above in each case and detects the echo reflected on the surface of the medium in the respective vessel. From the duration of the ultrasonic burst, the ultrasonic sensor then determines the distance between the ultrasonic transducer and the

Liquid surface. In this case, the ultrasonic sensor may optionally take into account further information, e.g. stored information about geometric properties of the microtiter plate, e.g. about diameter, depth of the individual vessels of the plate and / or their position relative to the ultrasonic sensor. Likewise, information about the temperature dependence of the speed of sound can be stored in a memory of the ultrasonic sensor. In conjunction with a temperature sensor, errors of the distance or transit time measurement due to different propagation velocities of the sound at different temperatures can be minimized in this way. By moving the microtiter plate relative to the sensor or vice versa, the levels in the individual vessels can be determined sequentially. This kind of

Level detection is slow, as the measurements of the levels in the individual cavities are carried out one after the other. In addition, conventionally only measurements can be performed on plates whose vessels have a sufficiently large inside diameter, since the sound lobes of conventional transducers or ultrasonic transducers would otherwise detect echoes from the edge of the vessel and possibly from levels in adjacent vessels. Instead of a sequential detection of the levels in each of the vessels of a microtiter plate with only one level sensor levels in multiple vessels of the microtiter plate can also be parallel or simultaneously with multiple level sensors be recorded. Again, conventional ultrasonic sensors that include relatively large housing and ultrasonic transducers can only be used in plates with a few vessels, these vessels must have sufficiently high internal diameters, so for example in plates with six or twelve wells. Otherwise disturbing echoes and / or mutually influencing adjacent ultrasonic transducers could lead to erroneous measurement results.

It is therefore an object of the present invention to provide a device for detecting fill levels in microtiter plates, which enables reliable and rapid detection of the levels in the individual vessels even with small vessel diameters and vessel distances or with small grid masses.

This object is achieved by an ultrasonic sensor according to the features of patent claim 1 and by a device for detecting fill levels in cavities of microtiter plates according to the features of patent claim 11.

The ultrasonic sensor according to the invention comprises a cuboid housing with a narrow side which has an effective width of less than 9 mm. Even taking into account possible housing tolerances, it is possible to line up several sensors in a grid of 9 mm, which corresponds to the grid of a conventional microtiter plate. The sensor housing comprises a plurality of stop surfaces and positioning and holding means as on the housing excellent resilient and non-resilient pins, holes, threads and the like, with which the sensors can be fixed in a defined position on correspondingly shaped mounting parts such as plates or brackets.

To prevent or reduce the risk of false echoes in the detection of levels in cavities with small internal cross-sections adapter sleeves on the

Ultrasonic transducer slipped and on this or on the housing, for. be held by a clamping or locking connection.

The adapter sleeves have on the converter side a larger, adapted to the converter inner diameter, on the opposite side corresponding to the opening cross-section of the cavities smaller inner diameter.

Based on some figures, some exemplary embodiments of the invention are described in more detail below. Show

1 shows a laterally attached to a support plate ultrasonic sensor in a first embodiment with a cuboid housing and a fitting sleeve, Figure 2 shows the ultrasonic sensor of Figure 1, but with a retaining clip for its attachment, Figure 3 shows an arrangement of three ultrasonic sensors according to Figure 2, wherein the Retaining clips the grid of the cavities with the to be detected Fill levels are held according to a mounting plate,

Figure 4 shows a device with three according to the

Raster of the microtiter plate juxtaposed ultrasonic sensors seen from the back,

Figure 5 shows a device with three in the double

Grid size of the microtiter plate on a mounting plate held ultrasonic sensors seen from the back,

FIG. 6 shows the device according to FIG. 4, but viewed from the front,

FIG. 7 shows a device analogous to FIG. 5, but viewed from the front, FIG. 8 shows a device with five ultrasound sensors lined up in the grid of the microtiter plate, each with a transducer-side stop surface bolted to a common mounting plate, seen from behind below,

FIG. 9 shows the device according to FIG. 8, seen from the front above,

FIG. 10 shows an ultrasonic sensor in another

Design, mounted in a recess of a mounting plate, where he by means of two

11 is a device with three ultrasonic sensors according to Figure 10, wherein the mounting plates parallel to each other at a distance of the grid of a FIG. 12 shows the ultrasound sensor according to FIG. 10, but seen from the sensor side, FIG. 13 shows the device according to FIG. 11, but viewed from the side of the ultrasound sensors, FIG. 14 shows a device with three pairs of

Ultrasonic sensors in the first embodiment, wherein the transducers of the adjacent

Ultrasonic sensors in the grid of the microtiter plate are spaced from each other, and wherein the distance between the adjacent pairs corresponds to twice the grid. The narrow sides of the sensor housing, the soft

Transducers are opposite, are connected to each other by means of a mounting plate, Figure 15 is an ultrasonic sensor with a

Fastening element in the form of a dovetail spring,

16 shows a device with three ultrasonic sensors attached to a mounting plate for detecting fill levels in cavities of a microtiter plate, FIG. 17 shows an ultrasonic sensor with magnets, FIG. 18 shows an ultrasonic sensor with a square

Base, Figure 19 shows an array with 25 ultrasonic sensors with a square base

Figure 20 is a perspective view of the ultrasonic sensor with removed adapter sleeve, obliquely from the front. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS FIG. 1 shows an inventive ultrasonic sensor 1 in a first embodiment. It comprises a substantially cuboid or cuboid sensor housing or short housing 3 with two parallel, opposite broad sides 5, 5 ¹ , and correspondingly two short narrow sides 7, 7 'and two long narrow sides 9, 9'. From an (not visible) recess on the lower narrow side 7, an ultrasonic transducer 11 protrudes slightly from the housing 3.

Optionally, the ultrasonic transducer 11 (as shown) may be encased by an adapter sleeve 13. This has on the converter side adapted to this, a little larger. Inner cross section on and on the other side a smaller inner diameter of e.g. a few millimeters.

This is dimensioned so that levels in small cavities 17 of microtiter plates 15 (Figure 3) can be detected trouble-free. The adapter sleeve 13 may e.g. be connected by means of a clamping, snap or locking device (not shown) with the ultrasonic transducer 11 or the housing 3.

Alternatively, such matching sleeves 13 may also be fixedly connected to the housing 3, at the upper narrow side 7 'opens a connection cable 19 in the sensor housing 3, where it is connected to a (not shown) sensor electronics (power and signal lines). Alternatively, as in an embodiment according to FIG. 11, a plug connection 19 'may also be provided. The ultrasonic transducer 11 is also connected to the sensor electronics.

On the broad sides 5, 5 ¹ and / or the short narrow sides 7, 7 'and / or the long narrow sides 9, 9' are positioning and holding means as the housing 3 outstanding resilient and non-resilient pin 21, holes 23, thread 25 and The like, with which the ultrasonic sensors 1 in a defined position on correspondingly formed mounting parts such as plates 29, sheets or brackets 31 {Figure 2) can be attached.

In the example of Figure 1, the ultrasonic sensor 1 is screwed to a mounting plate 29 by means of two screws 27 in through holes (not shown).

The narrow sides 7, 7 ', 9, 9' of the housing 3 have an effective width b of less than 9 mm, for example, 8.6 mm. "effective width" because, if necessary, at the broad sides 5, 5 'of the housing 3 excellent, resiliently supported on the housing 3 pin 21 when pressing these broad sides 5, 5' with slight pressure to corresponding mounting surfaces.

The housings 3 can thus be arranged in the raster of the effective width b with the broad sides 5, 5 ', e.g. aligned with each other in alignment. Preferably, however, the housings 3 are fastened by means of mounting plates 29, retaining clips 31 or other assembly aids, these being

Mounting aid in combination with the positioning and / or holding means on the housings 3 an assembly allow a plurality of housing 3 in a predetermined relative position to each other.

In particular, a plurality of ultrasonic sensors 1 can be attached in this way so that their ultrasonic transducers 11 are aligned and arranged in rows, the distances between adjacent ultrasonic transducers 11 correspond to the grid size s of the cavities 17 to be detected a microtiter plate 15, for example, s = 9 mm.

Of course, not all grid positions must be occupied. Distances between individual adjacent ultrasonic transducers 11 can also amount to a multiple of the grid dimension s. In the arrangements shown in FIGS. 3, 5, 7 and 14, three ultrasonic sensors 1 each are fastened to a mounting plate 29 in a row with a gap corresponding to the grid dimension s between each two adjacent ultrasonic sensors 1.

In the apparatus according to Figure 14 a further three ultrasonic sensors 1 are in an adjacent row in a similar manner screwed to the ^'mounting plate 29, such that the adjacent ultrasonic transducers have mutually a the grid spacing s corresponding distance 11 of both rows. Each ultrasonic transducer 11 is arranged in each case near the edge of the respective short narrow side 7, such that the distances of the ultrasonic transducer 11 to the long narrow side 9 ^? and to the two broad sides 5, 5 'of the respective ultrasonic sensor 1 are equal. The short narrow sides 7, 7 'of the housing 3 preferably have a length k which corresponds to a multiple of the grid dimension s of the microtiter plate or is slightly smaller than a multiple of this

Grid dimensions s, for example, a little less than 18 mm or 27 mm. In this way, it is possible to attach devices with a plurality of rows of ultrasonic sensors 1 to a holding plate 29 in such a way that the ultrasonic transducers 11 have distances in the individual rows and columns corresponding to the grid size s or an integral multiple thereof.

The sensor housing 3 comprises abutment surfaces or abutment surfaces which, when attached to a mounting plate 29 or other mounting aid, are brought into abutment with corresponding surfaces on the mounting aid and thus enable the positioning or alignment of the ultrasound sensor 1 in the required position.

In one embodiment of the ultrasonic sensor 1 according to FIGS. 1 to 9 and 14, the sides 5, 5 ', 7, 7' 9, 9 ^{1 of} the housing 3 form such stop surfaces.

Ultrasonic sensors can thus be used e.g. with one of the

Broad sides 5, 5 '(Figure 1) or with one of the short narrow sides 7, 7' (Figures 8, 9, 14) or with one of the long narrow sides 9, 9 ¹ (Figures 3 to 7) are secured to the mounting plate 29.

In an alternative embodiment of the ultrasonic sensor 1 according to the figures 10 to 13 protrude at two of Longitudinal sides 9 and 7 'attachment tabs 33 with holes out. To attach the sensor 1 to a mounting plate 29 in the form of a mounting plate, the mounting tabs 33 can be screwed to the mounting plate.

Preferably, the Mont ^' ageblech comprises a recess 35 which corresponds to the dimensions of the broad side 5 of the sensor housing 3.

The attachment tabs 33 and their abutment surfaces are set back by the thickness of the mounting plate relative to the outer surface of the broad side 5. The ultrasonic sensor 1 can thus be screwed to the mounting plate such that the sensor housing 3 is arranged in the recess 35, and that the broad side 5 of the housing 3 is flush with the mounting plate.

The thickness of the mounting plate thus has no influence on the relative position of a plurality of ultrasonic sensors 1. This is determined rather by the relative position of a plurality of interconnected mounting plates.

As an alternative to the connection by means of screws 27 ultrasonic sensors 1 can also by means of others

Connection techniques are attached to mounting parts such as the mounting plate 29.

FIG. 15 shows an ultrasonic sensor 1 in which two aligned sections of a dovetail spring 37 protrude on the long narrow side 9. FIG. 16 shows the attachment of a plurality of such ultrasonic sensors 1 to a mounting plate 29 with corresponding vertical dovetail grooves 39.

The ultrasonic sensors 1 can be inserted without tools from above into the guide grooves 39. The guide grooves 39 may be e.g. below have a stop surface or not continuously formed on the mounting plate 29.

When inserting an ultrasonic sensor 1, the end position is defined by the system of dovetail spring 37 on the stop surface of the guide groove 39.

Alternatively or in addition to the frictional attachment, e.g. also resilient or latching connecting elements for a positive connection between the ultrasonic sensor and the mounting plate 29 may be provided.

In a further embodiment according to FIG. 17, on the housing 3, e.g. in corresponding recesses on the long narrow side 9 magnets 41 are arranged and e.g. be connected by means of connection techniques such as gluing, notching, injection or injection with the housing 3.

On the mounting plate 29 are with the on the long

21 formed on the narrow side protruding pin 21 corresponding recesses, which define the position of the ultrasonic sensor 1 on the mounting plate 29 when it is attracted by the force of the magnets 41 of a ferromagnetic mounting plate 29. FIG. 18 shows another possible embodiment of an ultrasonic sensor 1, in which the broad sides 5, 5 'and the long narrow sides 9, 9' have identical effective widths b of approximately 8.6 mm. The bases of the housing 3 are thus square with a side of 8.6 mm.

Such housings can be connected to each other in cascades in any manner. FIG. 19 shows such a device with 5 × 5 ultrasonic sensors 1, which are arranged in a grid of 9 mm relative to each other in order to simultaneously detect the fill levels in the corresponding cavities 17 of a microtiter plate 15.

Of course, it is also possible to connect a plurality of ultrasonic sensors 1 directly to one another, wherein the contact surfaces of adjacent ultrasonic sensors 1 are brought into direct contact with one another and, e.g. be connected by screwing or by other joining techniques.

If required, also intermediate layers or spacers can be inserted between the individual sensors.

In such arrangements, housing tolerances have a greater effect on the accuracy of the positions of the individual

Ultrasonic transducer 11 as in the attachment to a common mounting plate 29th

As an alternative to ultrasonic sensors, sensors operating according to other principles, such as e.g. optical

Distance sensors or capacitive sensors in an analogous manner be constructed and connected to devices with several such sensors.

Figure 20 shows a perspective view of the ultrasonic sensor with the adapter sleeve 13 removed, obliquely from the front, in which a front part of the

Ultrasonic transducer 11 is arranged in an annular projection or bead 16 can be seen. Within the annular projection, a preferably approximately cylindrical recess 18 in the housing 3 of the ultrasonic sensor 1 is arranged.

In this case, the recess 18 is formed on one of the narrow sides 7, 7 ¹ , 9, 9 ^{1 of} the housing 3 and the ultrasonic transducer 11 is held in the region thereof.

In a preferred embodiment, the adapter sleeve 13 has extensions 20 on the side facing the ultrasonic transducer 11, see, for example, FIG. 17, which surround the annular projection 16, preferably from four sides, thus leading to a mechanical retention of the adapter sleeve 13 on the housing 3 ,

Depending on the design of the mechanical strength of the projections 20, there is a clamping or even latching connection with the projection 16 of the housing 3, if it has depressions or elevations, in which each associated elevations or depressions of the extensions 20 can engage.

Claims

claims

1. Ultrasonic sensor (1) for detecting fill levels in cavities (17) of microtiter plates (15), comprising an ultrasonic transducer (11) and a sensor electronics, which is arranged in a cuboid sensor housing (3), characterized in that the sensor housing (3 ) Has narrow sides (7, 1 ', 9, 9 ¹ ) whose effective width b is smaller than 9 mm, and in that the ultrasound transducer (11), in particular in the region of a recess (18), on one of these narrow sides (7, 7 ', 9, 9') is held on the housing (3).

2. Ultrasonic sensor (1) according to claim 1, wherein two opposite short narrow sides (7, 7 ¹ } are equal to or shorter than the two adjoining long narrow sides (9, 9 ¹ ) and the ultrasonic transducer (11) at the edge a short narrow side (7) is arranged, that the distances of the ultrasonic transducer (11) to the adjacent long narrow side (9) and to the two broad sides (5, 5 ¹ ) are the same size.

3. Ultrasonic sensor (1) according to one of claims 1 or 2, characterized in that the broad sides (5, 5 ¹ ) and / or the short narrow sides (7, 7 ') and / or the long narrow sides (9, 9') Contain contact surfaces or formed as abutment or abutment surfaces, or that on one or more of the narrow sides (7, 7 ', 9, 9') fastening tabs (33} with stop surfaces for protrude from a mounting plate (29) or other mounting hardware.

4. Ultrasonic sensor (1) according to one of claims 1 to 3, characterized in that at one or more

Side of the housing 3 positioning and holding means are formed.

5. ultrasonic sensor (1) according to claim 4, characterized in that the positioning and holding means on the housing 3 outstanding resilient and / or non-resilient pin (21) and / or holes (23) and / or thread (25) and / or Include dovetail springs (37).

6. Ultrasonic sensor (1) according to one of claims 1 to 5, characterized in that the lengths and / or the widths of the short narrow sides (7, 7 '} are slightly smaller than the grid size or s as an integer multiple of this grid dimension s Cavities (17) of a microtiter plate (15).

7. Ultrasonic sensor (1) according to one of claims 1 to 6, characterized in that the ultrasonic transducer (11) is encased by an adapter sleeve 13.

8. Ultrasonic sensor (1) according to one of claims 1 to 7, characterized in that a matching sleeves placed over the ultrasonic transducer (11) and held on this or on the housing, for example, preferably by a clamping or latching connection.

9. ultrasonic sensor (1) according to claim 7 or 8, characterized in that the adapter sleeves on the converter side have a larger and on the opposite side a smaller inner diameter.

10. Ultrasonic sensor (1) according to claim 9, characterized in that the adapter sleeves on the side opposite the transducer side have a smaller inner diameter of a few millimeters.

11. Device for detecting fill levels in cavities

(17) of microtiter plates (15), characterized in that a plurality of ultrasonic sensors (1) according to one of claims 1 to 10 are held by means of a mounting device with one or more mounting parts in a fixed position relative to each other, that the associated ultrasonic transducer (11) in one or more rows are arranged, and that the mutual distances of adjacent ultrasonic transducer (11) corresponds to the grid size s of the cavities (17) of these microtiter plates (15) or an integral multiple thereof.