DEVICE FOR COLLECTING LIQUID SAMPLES FOR A VAT

Abstract

It comprises, in addition to a sampling system (3), at the outlet of a vat (1) containing the liquid to be sampled, a selector (4) that establishes switching on an array of similar vats (1), and especially a suction unit (5) that operates by releasing compressed air into a nozzle (28); the airflow direction is controlled by a valve (29) between a direction directed toward the outlet (6), causing the suction of the liquid from the vat (1), and an opposite direction when the valve (29) is closed, feeding the liquid back into the vat (1) and cleaning the pipe (2).

Description

The invention relates to a device for collecting liquid samples from a vat, and even from a plurality of vats.

Such devices are common in the nuclear industry in order to analyse certain liquids loaded with irradiating materials. The corresponding devices are generally placed in shielded units, and they are manipulated through the use of remote manipulators. The liquid to be analysed is first present in a vat. It undergoes a suction through a pipe exiting into the top of the vat, which carries it toward a sampling holder whereon a small container, generally called a jug, has been installed, and it partially fills this jug. The excess liquid is evacuated toward an outlet or returns to the vat by flowing through the pipe, which is inclined, as soon as the suction has stopped.

A disadvantage with these devices is that the return to the vat is not complete and that droplets of liquid remain on the pipe, and then crystallise: this can be considered as a pollutant, and limits the quality of the following measurements by mixing with the samples sucked thereafter when the original liquid of the vat has been replaced with another. Another disadvantage with these devices is that it is difficult to join them to an array of vats in order to sample by choice samples from any one of them.

The invention has for object to eliminate these disadvantages, and above all to allow for a sufficient cleaning of the pipe and of the pipes leading to the vats without substantially complicating the device or having it lose its faculty to be able to be actuated via remote handling.

In a general form, it relates to a device for collecting liquid samples from at least one vat, comprising at least one pipe connecting to a respective vat and ending at an outlet at an end opposite the vat, a sampling jug holder of samples arranged on the pipe, and a suction unit of the contents of the vat in the pipe, characterised in that the suction unit comprises a nozzle arranged on the pipe, a compressed air inlet exiting in the nozzle, and the device further comprises a valve for sealing off the pipe, arranged on the pipe between the nozzle and the outlet.

This arrangement makes it possible to use compressed air to produce the suction by releasing pressure in the nozzle, then, as soon as the valve is closed, to clean the pipe by reversing its circulation toward the vat, which rejects the droplets of the liquid that are still contained therein.

The pipe advantageously comprises a small reservoir and the sampling jug holder is able to be connected to the small reservoir by the intermediary of a self-sealing quick-coupling in two portions, a first of said portions belonging to the small reservoir and a second of said portions comprising a needle which penetrates inside the small reservoir by passing through the first portion: this arrangement makes it possible to have a jug holder that can be manipulated easily via a remote manipulator in order to be installed on the device for collecting, then withdrawn to remove the jug and replace it without difficulty away from the device.

The pipe is advantageously wider on the side of the nozzle which leads from the outlet than toward the opposite side, which leads toward the vat. This device facilitates the proper direction of the compressed air when it arrives at the nozzle, toward the outlet when the valve is open, thanks to the lower resistance that it encounters from this side.

In order to facilitate the maintenance of the device although only remote manipulations are possible, it is recommended that the nozzle and the valve form a single and removable unit with a portion of the pipe and a portion of the compressed air inlet, said portions being connected to main portions of the pipe and of the compressed air inlet by capstan connectors.

According to a perfected embodiment, the device comprises a plurality of vats and pipes, the pipes connecting in turn to a selector, and then comprising a joint portion toward the outlet, whereon the nozzle and the valve are arranged.

The device can then serve several vats and several pipes. A favourable embodiment comprises a rotating selector which comprises a cylindrical mobile element provided with an external member for manoeuvring, the mobile element comprising an axial piercing directed toward the outlet and a radial piercing directed toward the vats and connections of the pipes arranged on a portion of a turn of the selector.

The invention shall now be described more completely and for the purposes of illustration in liaison with the figures.

FIG. 1 is a general view of the invention, FIG. 2 is a general view of the sampling (2A as a unit, 2B as an exploded view), FIG. 3 is a view of the selector, FIG. 4 a view of the nozzle and FIG. 5 a view of the capstan connector.

Reference shall first be made to FIG. 1. The liquid to be sampled is initially located in storage vats 1. Pipes 2 for sampling exit at the top of the vats 1, pass through a sampling installation 3, respective, are connected to a joint selector 4, then pass through a suction unit 5, and finish toward an outlet 6 which is a reservoir for collecting the excess sucked liquid. The main elements of the device shall now be described successively. The pipes 2 rise first from the vats 1, to the sampling installations 3, then fall little by little toward the outlet 6, opposite the vats 1 and therefore separate from them.

The sampling system 3 is shown in detail in FIG. 2. It first comprises a mobile portion constituted of a manual valve 7 of which the top is occupied by a cylindrical case 8 open at the top comprising an upper needle 9 whereon can be installed the jug 10 and a pivoting portion 17 making it possible to imprison the jug 10 in its housing, and the base via a needle 11 whereon is fixed a female self-sealing quick-coupling 18 and through which the sampling will be carried out. In the case of a plurality of vats to be sampled, this mobile portion is displaced and is provided with a new jug.

The unit further comprises a fixed portion comprising a small reservoir 12 closed by a male self-sealing quick-coupling 13 and wherein exit a lower surface 14 of the pipe 2 leading to the vat 1, a second surface 15 of the pipe 2 leading to the selector 4. In order to take a sample, the mobile portion is installed on the fixed portion, through the insertion of the needle 11 in the coupling 13 to connexion of the female quick-coupling 18 on the male quick-coupling 13. A new jug 10 was installed beforehand in the mobile portion on the needle 9, the manual valve 7 being in closed position. These jugs are hermetic and the vacuum therein is created at the onset. Their septum 16 is made of rubber and can be pierced by the needle 9 when the jugs 10 are pressed onto it. This is done when a suction has made it possible to fill the small reservoir 12 with the liquid to be sampled: the manual valve 7 is open and the vacuum present in the jug 10 then sucks a portion of the liquid via the needle 11, the manual valve 7 and the needle 9. After which, the manual valve 7 can be closed, and the mobile portion can be withdrawn through disconnection of the quick-couplings 13 and 18. The jug 10 can be withdrawn, and the piercing made in the septum 16 closes itself.

Reference is again made to FIG. 1, and to FIG. 3, for the description of the selector 4. It comprises a casing 19 occupied by a cylindrical plug 20, provided with a member for manoeuvring in the form of a square shaft tip 21 protruding out of the casing 19. To the casing 19 is connected connectors 22 extending the second surfaces 13 of the pipes 2 and which extend in a radiating direction from the casing 19 over a portion of the turn. Another connector 23 is connected to the casing 19, but this time in the axial direction, opposite the square shaft tip 21. This connector 23 is connected to the suction unit 5. The plug 20 contains a piercing 43 leading to the connector 23 by an axial portion and, according to the rotation of the square shaft tip 21, to one or the other of the connectors 22 via a radial portion. The selector 4 makes it possible to select the vat 1 from which the liquid is sampled, according to its manoeuvre and by means of the arrangements described now.

The suction unit 5 comprises a removable portion of the pipe 2, a removable portion 25 of a compressed air inlet 26 connected to a source of compressed air 27, and, installed on the removable portion 24, a nozzle 28 and a valve 29. The nozzle 28, shown in FIG. 4, comprises a venturi 30 and the removable portion 25 of the compressed air inlet 26 exits therein. The compressed air with a release of pressure in the venturi 30 acquires a supersonic speed able to carry out the suction of the liquid by the pipe 2. The valve 29 comprises an actuator 31 extending above the removable portion 24 and controlling a valve to open or close the removable portion 24 by the intermediary of a rod 33.

The suction unit 5 can be withdrawn from the rest of the device and then put back into place, being connected via three capstan connectors 34 to the compressed air inlet 26, to the connector 23 at the outlet of the selector 4 and to a third surface 35 of the pipe 2 after the valve 29 which leads to the outlet 6. The capstan connectors 34, shown more completely in FIG. 5, include a case 36 and an end 37 to be assembled together, the seal being formed by a double-cone seal 38 placed between them. The case 36 carried a container 39 in the shape of a trough receiving and maintaining the end of the tip 37. In addition, a capstan nut 40, engaged on an external threading of the tip 37, is also maintained by an external lip 41 of the container 39. A rotation applied to the capstan nut 40 displaces the tip 37 axially in the container 39 and compresses it against the case 36 by crushing the double-cone seal 38.

FIGS. 1 and 3 further show a discharge pipe 42 connecting the interior of the casing 19 to the outlet 6, and intended for the evacuation of the humidity in the selector 4.

When the compressed air is supplied, with the valve 29 open, the liquid is sucked from the chosen vat 1 toward the suction unit 5 and the outlet 6 fills the small reservoir 12 where it can be sampled. Note that the air inlet exits perpendicularly in the venturi 30, but the proper direction of air circulation is guaranteed by selecting the surfaces 14, 15 and 35 of the pipe 2 with diameters which become successively wider from the vat 1 to the outlet 6 (without considering the diameters at the nozzle 28), which can also be in a vacuum in relation to the vat 1: the resistance to the flow of the compressed air is therefore less substantial toward the outlet 6. But when the suction stops, the closing of the valve 29 has for effect to close the removable portion 24 and to inverse the direction of the flow of the compressed air toward the vat 1, by feeding back therein the liquid which may have stagnated in the device and in particular in the small reservoir 12 and the pipe 2. No other manoeuvre is required.

All of these movements are easy to accomplish through ordinary remote manipulators, with limited dexterity.

Claims

1-6. (canceled)

7. Device for collecting liquid samples from at least one vat (1), comprising at least one pipe (2) connecting to a respective vat and exiting at an outlet (6) separate from the vat, a sampling jug holder (8) arranged on the pipe for jugs (10) sampling the samples, and a suction unit of the contents of the vat in the pipe, the suction unit comprising a nozzle (28) arranged on the pipe, a compressed air inlet (26) exiting in the nozzle, characterised in that the device further comprises a valve (29) for sealing off the pipe, arranged on the pipe between the nozzle (28) and the outlet (6), and the outlet is at an end of the pipe (2) which is opposite the vat.

8. Device for collecting samples according to claim 7, characterised in that the pipe (2) is wider on one side of the nozzle (28) toward the outlet (6) than toward a side of the nozzle toward the vat.

9. Device for collecting samples according to claim 7, characterised in that the nozzle and the valve form a single removable unit with a removable portion (24) of the pipe (2) and a removable portion (25) of the compressed air inlet (26), said removable portions being connected to main portions of the pipe and of the compressed air inlet via capstan connectors (34).

10. Device for collecting samples according to claim 7, characterised in that it comprises a plurality of vats (1) and pipes (2), the pipes connecting to each other at a selector (4), and then comprising a joint portion toward the outlet (6), whereon the nozzle (28) and the valve (29) are arranged.

11. Device for collecting samples according to claim 10, characterised in that the selector rotates and comprises a cylindrical mobile portion (20) provided with an external member (21) for manoeuvring, the mobile element comprising an axial piercing directed toward the outlet and a radial piercing directed toward the vats and connectors (22) of the pipes arranged on a portion of the selector turn.

12. Device for collecting samples according to claim 7, characterised in that the pipe (2) comprises a small reservoir (12), and the sampling jug holder (8) is able to be connected on the small reservoir (12) by the intermediary of a self-sealing quick-coupling in two portions (13, 18), a first of said portions belonging to the small reservoir and a second of said portions comprising a needle (11) which penetrates inside the small reservoir (12) by passing through the first portion.