FR2853964A1 - Liquid sampler with hollow needle and cup has needle fitted in sleeve bore and spring to hold sleeve in rest position with apertures closed - Google Patents

Abstract

A sampler comprises a needle (40) with an aspiration end (44) linked to a reservoir that can be fed with a liquid from a circuit under depression, while its pointed tip (46) is designed to perforate a cup (78) under depression. It also has a main body (22) surrounding a sliding sleeve (32) and having at least one aperture (72) linking the reservoir to the aspiration end of the needle. The needle is fixed in the sleeve's bore (42), and there is a spring (56) between the body and sleeve that holds the sleeve in a rest position in which the apertures (72) are closed by a shutter. The apertures are opened by pushing the sleeve against the effort of the spring.

Description

DEVICE FOR TAKING LIQUID SAMPLES

DESCRIPTION

TECHNICAL AREA

  The present invention relates to a device for taking liquid samples comprising a needle, one suction end of which is capable of communicating with a reservoir capable of being supplied with liquid by a vacuum circuit, and of which a pointed opposite end is able to perforate a jug in depression, so that a sample of liquid is automatically taken from the jug under the effect of a suction caused by the depression prevailing inside the latter.

  This type of device for taking samples finds in particular applications in the fields of the nuclear industry, the chemical industry, or even the pharmaceutical industry. It makes it possible to take liquid samples automatically, which makes it particularly suitable for taking liquids dangerous for humans and / or the environment. In addition, the packaging of the liquid sample taken in a jug makes it possible to carry out all the measurements and analyzes desired on this sample later.

B 14315 AP

STATE OF THE PRIOR ART

  In this technical field, several achievements have already been proposed.

  It is in fact known that sampling installations include a sampling bench such as that described in documents FR-A1 401 298 and FR-A-2 058 751, equipped with devices for taking liquid samples such as that described in document EP-A-0 078 211, these devices being supplied with liquid by vacuum circuits such as that described in document EP-A-0 296 917.

  In this type of installation, each of the needles of the liquid sample collection devices connects the interior of the glove box of the sampling bench, and the circuit by which the liquid to be sampled is brought to the device. of collection with the needle concerned.

  Consequently, each time a sample has to be taken, the actuation of the vacuum pump of the circuit supplying the reservoir of the sample device inevitably causes, through the needle, a suction of a certain volume of air present in the glove box of the sampling bench.

  Thus, this phenomenon is directly reflected in a significant increase in the flow of air treated in the vacuum circuits, when the number of withdrawals becomes high.

  Furthermore, it has also been observed that these repeated aspirations lead to an extension of the operating time of the pumps during each sampling, and lead to an increase in the operating cost of the installation as well as to a reduction of the service life of these different pumps.

  To overcome these drawbacks, it was then proposed to design a device for taking liquid samples, capable of reducing the air leakage rate between the glove box of the sampling bench and the vacuum circuit 10 supplying the liquid tank. This device, described in document FR-A-2 731 275, is designed so that a sliding sleeve is able to cover normally the upper part of a needle having an eye made so as to open laterally, the sleeve sliding also being able to be pushed back in order to allow the eye and the pointed end of this needle to be released during the sampling operations.

  Although it makes it possible to prevent the vacuum pump of the circuit from acting excessively on the air contained in the glove box, this device for taking liquid samples nevertheless generates certain major drawbacks.

  In fact, it is first of all indicated that the use of such a device generates the appearance of a flow of liquid on the external surface of the needle, mainly due to the lateral position of the eye, and of the closing principle of the latter using the sliding sleeve 30. In this way, the observed flow can result in contamination of the B 14315 AP sampling area, as well as that of the jug intended to collect the liquid sample.

  In addition, the presence of liquid on the outer surface of the needle indicates that this liquid 5 circulates at a calibrated clearance located between this same needle and the sliding sleeve. Consequently, the risks of the sleeve seizing up on the needle are relatively high. In this regard, it is noted that the seal between the needle and the sliding sleeve 10 is very difficult to obtain, particularly when the liquid located in the reservoir of the device is kept under pressure.

  On the other hand, it has been observed that the maintenance and stitching operations of the jug 15 cause high risks of twisting of the needle, which can result in deterioration or even breakage of the latter.

  Finally, other drawbacks directly linked to the very design of the device have also been detected, such as the poor healing of the plug due to the specific shape of the pointed end of the needle having a lateral eye, the subsistence of a drop of liquid at the eye of the needle liable to contaminate the jug, or else the non-negligible difficulty of rinsing such a device.

  PRESENTATION OF THE INVENTION The object of the invention is therefore to propose a device for taking liquid samples 30 comprising a needle, one suction end of which is capable of communicating with a reservoir suitable for B 14315 A? be supplied with liquid by a vacuum circuit, and of which a pointed opposite end is capable of perforating a jug in depression, the device at least partially remedying the drawbacks 5 mentioned above relating to the embodiments of the prior art.

  To do this, the invention relates to a device for taking liquid samples comprising a needle, one suction end 10 of which is capable of communicating with a reservoir capable of being supplied with liquid by a vacuum circuit, and one of which opposite pointed end is capable of perforating a jug in depression, the device comprising a main body inside which is capable of sliding a sleeve having a bore cooperating with the needle, the main body comprising at least one opening allowing communication between the reservoir and the suction end of the needle. According to the invention, the needle is mounted integrally in the bore of the sleeve, and the device further comprises elastic means normally maintaining the sleeve in a rest position in which closure means, integral with this sleeve, provide closure for each opening of the main body, the sleeve being capable of being pushed back against the elastic means so that the closure means release each opening of the main body.

  Advantageously, due to the presence of the sealing means normally preventing communication between the liquid reservoir and the suction end of the needle, the actuation of the vacuum pump of the vacuum circuit supplying the tank is in no way influenced by the air located in the glove box of the sampling bench. The operating cost of the associated installation as well as the lifetime of the pumps are therefore perfectly optimized.

  Furthermore, unlike the device for taking liquid samples described in document FR-A-2 731 275, the device according to the invention is designed so that the needle is integral with the sleeve. The risks of jamming of the sleeve around the needle are therefore reduced to nothing, as are the risks of twisting of this needle during maintenance operations and pitting of the jug.

  Still advantageously, the specific design aiming at closing off each opening of the main body using closing means 20 integral with the sleeve makes it possible to obtain a very good seal, ensuring that the liquid present inside of the reservoir cannot reach the suction end of the needle, even when this liquid is kept under pressure in the reservoir.

  Furthermore, when it is desired to take a liquid sample, each opening of the body of the device can then be released by the closure means, following a sliding of the sleeve which can, for example, simply result from the appearance of a stitching pressure.

  B 14315 AP In addition, it is noted that the needle can be made so that its eye is not arranged laterally, but preferably placed at the pointed end so as not to generate flow. on the outer surface of this needle, and consequently avoid contamination of the sampling area as well as that of the jug intended to collect the liquid sample. As such, it is specified that the needle is not normally covered by the sleeve, the rinsing operations of the device therefore no longer pose any problem.

  Finally, the eye of the needle can be placed at the pointed end, the latter 15 can then advantageously have a beveled profile favorable to good healing of the jug.

  Preferably, the opening of the main body is partially delimited by a bore formed in a suction end of the main body, the bore being traversed by the sleeve of the device.

  Thus, in such a configuration, the bore made at the suction end of the main body and the sleeve passing therethrough jointly form a first annular space, into which the liquid is able to penetrate.

  Furthermore, in order to make the reservoir of the device communicate with the suction end of the needle, provision may be made for the sleeve to have at least one perforation opening out on the one hand into the B 1. 4315 AP first annular space , and secondly in the bore of this sleeve.

  Preferably, the closure means comprise a closure element mounted integrally around the sleeve and at least partially projecting from the suction end of the main body, the closure element having a frustoconical surface capable of coming in abutment against the bore made at the suction end of the main body 10.

  Still preferably, a bore is provided at an ejection end of the main body, forming jointly with the sleeve a second annular space. In this case, the elastic means can then comprise a compression spring mounted in this second annular space, so as to apply the sleeve against a stop formed at the ejection end of the main body.

  Other advantages and characteristics of the invention will appear in the detailed non-limiting description below.

BRIEF DESCRIPTION OF THE DRAWINGS

  This description will be made with reference to the appended drawings in which i - FIG. 1 represents a partial view in longitudinal section of a device for taking liquid samples, according to a preferred embodiment of the present invention, - FIG. 2 shows an enlarged view of an interchangeable part of the device shown B 14315 AP o in Figure 1, when the latter occupies a rest position in which no removal is made, and - Figure 3 is a view similar to that 5 shown in Figure 2, when the device occupies an active position in which a liquid sample is taken.

  DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT With reference to FIG. 1, there is partially shown a device 1 for taking liquid samples, according to a preferred embodiment of the present invention.

  The device 1 comprises a support 2, externally having the shape of a cylinder with a substantially vertical axis 15 4. It is noted that this support 2 is intended to be mounted in a sealed manner in the bottom of a glove box of a sampling bench (not shown), such as that described in document EPA-0 078 211.

  The support 2 comprises a reservoir 6 at a central part, the reservoir 6 preferably being cylindrical with an axis identical to the vertical axis 4 of the support 2. On the other hand, above the reservoir 6, the support 2 has a tubular shape and delimits a chamber 8, closed upwards by a plug 10.

  A liquid inlet pipe 12 runs vertically in the support 2, in a position offset laterally with respect to the tank 6, and opens into the chamber 8 at its upper end. Furthermore, the lower end of the inlet pipe 12 is formed so that B 14315 AP communicates with the upstream part of a vacuum circuit such as that described in document EP-A-0 296 917. A pipe drain 14 slightly inclined with respect to the vertical axis 4 is arranged so as to 5 connect the bottom of the tank 6 and the liquid inlet pipe 12.

  In the same way, a liquid outlet pipe 16, oriented vertically, is also formed in the support 2 at a location offset laterally with respect to the reservoir 6. The outlet pipe 16 opens into the chamber 8 at its upper end, and its lower end is made so as to communicate with the downstream part of the vacuum circuit.

  Still with reference to FIG. 1, the device 1 for taking liquid samples further comprises an interchangeable part 18, intended to be mounted in an opening 20 of circular section and of axis identical to the vertical axis 4, this 20 opening 20 being formed for this purpose in the plug of the device 1. As such, it is indicated that the mounting and dismounting of the interchangeable part 18 may preferably be carried out using appropriate tools, fitted in known manner the 25 classic sampling benches.

  Referring now to Figure 2, there is shown in more detail the interchangeable part 18 of the device 1, when the latter occupies a rest position in which no sampling is carried out.

  B 14315 AP As can be seen in this FIG. 2, the interchangeable part 18 comprises a main body 22 of substantially tubular shape, designed to be fitted in a sealed manner in the opening 20 5 of the plug 10. To do this, the main body 22 is provided with an annular groove 24 in which an O-ring seal 26 is mounted, normally in contact with the wall of the opening 20.

  The main body 22, mounted coaxially 10 on the support 2, is provided with a suction end 28 intended to be arranged at the level of the reservoir 6 when the interchangeable part 18 is installed on the plug 10. This suction end 28 is provided with a bore 30 of axis 15 substantially identical to the vertical axis 4, this bore forming with a sleeve 32 slidably mounted inside the main body 22, a first annular space 34. It is noted that to ensure the sliding of the sleeve 32 in a substantially vertical direction, the main body 22 of the device 1 comprises in particular a central channel 33 with an axis identical to the axis of the bore 30, this channel 33 being joined by the outer surface of a central part of the sleeve 32.

  In addition, the sleeve 32 extends upwards in the form of a grip ring 36 projecting from the main body 22, and downwards in the form of a portion 38 also projecting from the suction end. 28 of this main body 22.

  At the end of the sleeve 32 comprising the gripping ring 36, a straight hollow needle B 14315 AP 40 is integrally mounted inside a bore 42 provided in this same sleeve 32, the bore 42 and the needle 40 therefore being coaxial with an axis substantially identical to the vertical axis 4. Thus, 5 a low suction end 44 of needle 40 opens into bore 42, while an opposite pointed end 46 projects from sleeve 32 and main body 22, upwards. It is specified that preferably, the pointed end 46 is provided with an eye 47 lying in the vertical extension of a central channel 49 of the needle 40, this channel 49 consequently opening vertically upwards in the box. glove from the sampling bench above the plug 10. In addition, as shown in FIG. 15 2, it is possible to provide that the pointed end 46 has a bevelled profile, the eye 47 then being arranged in an inclined manner at the level of this same beveled profile.

  Still with reference to FIG. 2, it can be seen that the sleeve 32 comprises a plurality of 20 perforations 48, arranged near the portion 38 projecting from the suction end 28 of the body 22. These perforations 48 are produced at level of a lower part of the bore 42, substantially radially so as to open on the one hand into the first annular space 34, and on the other hand into this bore 42 of the sleeve 32. Consequently, the first annular space 34 communicates with the suction end 44 of the needle 40.

  Furthermore, another bore 52 is provided 30 on the main body 22 of the device 1, at a high ejection end 50 opposite B 14315 AP the suction end 28. This bore 52, preferably d axis identical to the vertical axis 4 and located in the extension of the central channel 33 upwards, forms, jointly with the sleeve 32, a second annular space 54 in which elastic means take place, the latter preferably occurring under the in the form of a helical compression spring 56.

  The helical compression spring 56 is in support in the lower part against a shoulder 58 provided in the main body 22, and in support in the upper part against another shoulder 60 provided in the sleeve 32.

  By way of illustrative example, the lower part of the spring 56 is not directly in abutment against the shoulder 58, but is in contact with a ring 61 positioned against this same shoulder 58. In this regard, it is noted that the presence of this ring 61 is in particular justified by the fact that it contributes to the production of an annular groove 62, in which an O-ring 64 is arranged in order to establish the seal between the main body 22 and the surface outside of sleeve 32.

  Thus, with such a configuration, the spring 56 constitutes an elastic means for returning the sleeve 32 to a normal rest position in which a shoulder 65, provided on the latter, is held against a stop 66 formed in the main body 22 of the device 1, at the ejection end 50.

  The portion 38 of the sleeve 32 projecting from the suction end 28 is integral with shutter means B 14315 AP 68, preferably taking the form of a shutter element 70 mounted around the portion 38 and also forming at least partially projecting from the suction end 28 of the main body 22.

  This closure element 70 is designed so as to be able to close an opening 72 provided on the main body 22, this opening 72 authorizing communication between the reservoir 6 and the suction end 44 of the needle 40. As shown in 10 in FIG. 2, it can be seen that the opening 72 is a substantially annular opening with an axis identical to the vertical axis 4 when the interchangeable part 18 is mounted on the plug 10, and is partially delimited by a frustoconical abutment surface low 74 15 of the bore 30. As such, it is indicated that when the device 1 occupies a rest position in which no liquid is taken, such as that shown in this same figure 2, the element shutter 70 completely closes the opening 20 72 while being in contact with the surface 74, so that the liquid present in the reservoir 6 cannot penetrate inside the first annular space 34.

  In other words, when the sleeve 32 is held normally in its rest position 25 against the stop 66 of the main body 22, this sleeve 32 keeps the closure element 70 in contact with the low frustoconical stop surface 74 so to completely seal the opening 72, so that communication between the reservoir 6 and the suction end 44 of the needle 40 is prohibited, even B 14315 AP when the liquid is under pressure inside of this tank 6.

  To achieve such a goal, the closure element 70 may preferably have, in the upper part 5, a frustoconical surface 76 capable of coming into abutment against the low frustoconical abutment surface 74 of the bore 30 made at the level of the the suction end 28 of the main body 22. Naturally, the frustoconical surface 76 is preferably designed so as to fully match the low frustoconical abutment surface 74 of the bore 30.

  Consequently, in the normal resting position of the sleeve 32, this involving the abutment of the frustoconical surface 76 against the bore 30 15 under the effect of the compression helical spring 56, it is then possible to operate the vacuum circuit, while avoiding that the vacuum pump of this circuit needlessly sucks the air present in the glove box of the sampling bench.

  Referring to Figure 3, there is shown in more detail the interchangeable part 18 of the device 1, when the latter occupies an active position in which a liquid sample is taken.

  When a jug 78 is applied against the high pointed end 46 of the needle 40, and moved downwards, this pointed end 46 pierces the cover 81 of the jug 78 into which it then penetrates gradually, until this cover 81 30 comes into abutment against an upper surface 82 of the gripping ring 36 of the sleeve 32. Once this contact has been established, the movement of the jug 78 downwards causes a pressure to appear. stitching exerted by this same jug 78 on the sleeve 32, this stitching pressure having the consequence of pushing the sleeve 32 against the helical compression spring 56. Of course, without departing from the scope of the invention, it would be also possible to provide that the stitching pressure appears before the contact between the cover 81 and the external surface 10 82 of the ring 36, by simple friction between the cover 81 and the external surface of the needle 40 through ant this same seal.

  The sliding down of the sleeve 32 in the central channel 33 causes the annular opening 72 to be released, and consequently allows communication between the liquid reservoir 6 and the suction end 44 of the needle 40. Indeed, as can be seen in FIG. 3, when the sleeve 32 is sufficiently pushed back, the annular opening 72 is then delimited internally by the external surface of this sleeve 32, as well as externally by the abutment surface low frustoconical 74 of the bore 30 of the main body 22.

  Of course, the bore 30 could also be made in a conventional manner, without having a low frustoconical abutment surface 74, so that the annular opening 72 would then be delimited externally by a simple low circular edge.

  Thus, the eye 47 of the needle 40 being located inside the jug 78, the depression which prevails therein automatically ensures the suction of a sample of liquid present in the reservoir 6. Indeed, under the effect of this depression, the liquid present in the reservoir 6 successively borrows the annular opening 72, the first annular space 34, the radial perforations 48, the bore 42 of the sleeve 32, the suction end 44 of the hollow needle 40, the central channel 49 of the needle 40, the pointed end 46 of this same needle, and finally the eye 47 in order to reach an interior space 80 of the jug 78.

  Furthermore, when it is desired to complete the collection of liquid, the jug 78 is moved upwards, which also automatically causes the needle 40 and the sleeve 32 to move upwards, always under the effect of the spring 56.

  During the movement of this jug 78, the contact between the cover 81 and the outer surface 82 of the gripping ring 36 is retained until the sleeve 32 returns to its rest position, in which it is held against the abutment 66 of the main body 22, and in which the closure element closes the annular opening 72.

  Following the completion of this closure, the communication between the reservoir 6 and the suction end 44 of the needle 40 is interrupted, while the pointed end 46 and the eye 47 of this needle 40 are still housed in the interior space 80 of the jug 78. This then advantageously allows at least part of the liquid present in the interchangeable part 18 to be B 14315 AP automatically sucked into the space 80 under the effect of the vacuum prevailing at inside the jug 78.

  In this way, when the jug 78 is completely withdrawn from the device 1 and the needle 40 has been fully extracted from the latter, no drop of liquid remains at the eye 47 and the pointed end 46 of this needle. 40.

  Of course, various modifications can be made by a person skilled in the art to the device 1 for taking liquid samples which has just been described, only by way of nonlimiting example.

B 14315 AP

Claims (7)

  1. Device (1) for taking liquid samples comprising a needle (40), one suction end (44) of which is capable of communicating with a reservoir (6) capable of being supplied with liquid by a vacuum circuit, and of which a pointed opposite end (46) is capable of perforating a jug (78) in depression, said device (1) comprising a main body (22) inside which 10 is capable of sliding a sleeve (32) having a bore (42) cooperating with said needle (40), the main body (22) comprising at least one opening (72) allowing communication between the reservoir (6) and the suction end (44) of the needle ( 40), characterized in that the needle (40) is mounted integrally in the bore (42) of said sleeve (32), and in that the device (1) further comprises elastic means (56) now normally the sleeve (32) in a rest position in which shutter means (68), integral with this sleeve (32), seal off each opening (72) of the main body (22), the sleeve (32) being able to be pushed back against the elastic means (56) so that the shutter means (68) release each opening (72) from the main body (22).   2. Device (1) according to claim 1, characterized in that the opening (72) of the main body (22) is partially delimited by a bore (30) formed in a suction end 30 (28) of the main body (22), said bore (30) being traversed by the sleeve (32) of the device (1).   B 14315 AP 3. Device (1) according to claim 2, characterized in that the bore (30) formed at the suction end (28) of the main body (22) and the sleeve (32) passing through it, form 5 together a first annular space (34) into which the liquid is able to penetrate.   4. Device (1) according to claim 3, characterized in that the sleeve (32) comprises at least one perforation (48) opening on the one hand into the first annular space (34), and on the other hand into the 'bore (42) of said sleeve (32).   5. Device (1) according to any one of claims 2 to 4, characterized in that the closure means (68) comprise a closure element (70) mounted integrally around the sleeve (32) and making the at least partially protruding from the suction end (28) of the main body (22), the closure element (70) having a frustoconical surface (76) capable of abutting against the bore 20 (30) formed at the suction end (28) of the main body (22).   6. Device (1) according to any one of the preceding claims, characterized in that a bore (52) formed at an ejection end (50) of the main body (22) forms jointly with the sleeve (32) a second annular space (54).   7. Device (1) according to claim 6, characterized in that the elastic means comprise a compression spring (56) mounted in said second annular space (54), so as to apply the sleeve B 14315 AP (32) against a stop (66) formed at the ejection end (50) of the main body (22). B 14315 AP