DEVICE FOR TAKING UNDISTURBED AND PRESSURIZED SAMPLES OF GROUND-WATER (AND GAS) IN OPEN SYSTEMS

Abstract: Sampling device for taking pressurized samples of liquid and/or gas. The sampling device contains a hermetically sealed and an at least partly evacuated sample container (9). The sample container is sealed by an element (23) of flexible material. The sampling device does also contain a double-ended hypodermic needle (16). When activating the sampling device, which is made by applying an over-pressure, the hypodermic needle (16) penetrates through the element (23) of flexible material whereby a sample is being transferred to the sample container (9).

Description: Device for taking undisturbed and pressurized samples of groundwater (and gas) in open systems. .Below follows a brief description of a new device for the taking of undisturbed and pressurized samples of water (and/or gas) in open systems. The basic struc¬ ture of the device including some examples of applica¬ tions are shown in the accompanying drawings,Figs. 1-7. Figures la-d show some different applications for the sampling device, viz.: - Fig. la : sampling of water in dril 1-holes in soil or rock - Fig. lb sampling of water in wells - Fig. lc sampling in lakes or at sea - Fig. Id- sampling of water in sewer lines At the taking of a sample the sampling device is lowered down to the desired elevation with the aid of a flexible tube (2) which is sealingly connected to the sampling device (1). The sampling device is activated by the aid of an over-pressure (p) which is temporarily applied in the tube (2). For example, the over-pressure can simply be applied with the aid of a hand-pump or a cylinder with compressed gas, equipped with a pressure regulation valve. An embodiment of the sampling device is shown in Figs. 2-4. The sampling device contains a hermetically sealed sample container (9). The sample container (9) is sealed with stopper (23) of elastic material which is mounted in a screw-cap (22). The sample container can for example be evacuated before it is mounted in the sampling device. The sample container (9) rests against two compression springs (17;18) having mutually diffe¬ rent spring characteristics. Alternatively, the two compression springs (17;18) can be replaced with one single compression spring (32) having a variable pitch which gives it a progressive spring charac- teristic, cf. Fig. 9. In the lowermost end, the sampling device (1) is closed with a stopper (21) av elastic material. The sampling device does also contain a double-sided hypodermic needle (16) which is mounted in a moveable holder (13) which rests against a compression spring (19). In its upper end the sampling device contains a piston (11) which is sealed against the inside of the housing (10) with the aid of a sealing element (12). In the uppermost end of the sampling device is mounted a connector (26) for making possible a leak-tight connection of the tube (2). When the sample container is inserted into the sampling device a prestress is generated in the compression springs (17;18;19). Figures 3-4 illustrate the sampling procedure. When an over-pressure (p) is applied in the tube (2) the piston (11) will be displaced downwards and simul¬ taneously it pushes also the sample container (9) down- wards, cf. Fig.3. When the screw-cap (22) has reached its end-position and rests against the needle holder (13), the double-ended needle has penetrated both the stopper (23) and the stopper (21). By choosing a suitable relationship between the characteristics of the compression springs (17;18;19), alternatively the com¬ pression springs (32;19), it is possible to make the hypodermic needle to penetrate firstly the stopper (21) and secondly the stopper (23). When the hypodermic needle has penetrated the two sealing elements (21;23), liquid (and/or gas) starts to fill the sample container (9). The over-pressure (p) is maintained until equili¬ brium has been reached between the pressure (p ) , acting in the liquid at the sampling elevation, and the pres¬ sure inside the sample container. When the over-pressure (p) in the activation tube (2) is released the needle holder (13) and the sample container (9) will be dis¬ placed upwards due to the prestress of the compression springs (17;18;19), alternatively compression springs (32;19). By choosing a suitable relationship between the characteristics of the compression springs (see above), the hypodermic needle can firstly be pulled out of the stopper (23) before the other end of the needle is pulled out of the stopper (21). In this manner a hermetically sealed sample is obtained which is pres¬ surized to the same pressure (P n )/ which acts in the liquid at the sampling elevation. By choosing suitable material for the stoppers (21;23) and by designing the sampling device in an adequate manner it can be made possible to take pressurized samples at ambient pressures (p Q ) as high as 100-200 bars. Figure 8 shows a filtering device which can be attached to the lower end of the sampling device instead of the stopper (21), cf. Fig. 7. The filtering device contains among other things a stopper (21) and a filter (28) which is mounted on a holder (29). The end-surfaces of the filter rest against sealing discs (31) of elastic material.

Claims: Claims 1. A device for taking pressurized samples of liquid and/or gas, comprising a housing (10) which contains at least one mobile, completely or partially evacuated sample container (9) , of which the end facing downwards is hermetically sealed by a first element (23) of flexible material, furthermore the housing (10) contains a movable piston (11) which is sealed against the inside of the housing, a double-ended hypodermic needle (16) which is mounted in a mobile holder (13), means (17;18) to exert a counterforce on the sample container (9) when this is displaced longitudinally towards the holder (13), a second element (21) of flexible material which is mounted in a second holder (20) connected to the lowermost end of the housing (10), means (19) to exert a counterforce against the holder (13) when this is displaced towards the plug (14) characterized in that when a sample of liquid/and gas is to be taken the device is activated with the aid of an over-pressure (p) which is applied to the upper end of the housing (10) by means of a tube (2) connected to the housing, whereby the piston (11) together with the sample container (9) will be displaced longitudinally downwards simultaneously as the double- ended hypodermic needle due to the action of the ele¬ ments (17;18) and (19) is brought to selectively penetrate firstly the second element (21) and secondly the first element (23) whereby a sample can be transferred to the container (9) . 2. A device as defined in claim 1, characterized in that the counteracting means are compression springs (17;18) and (19) . 3. A device as defined of claims 1 and 2, characterized in that the compression springs (17;18) are replaced by one single compression spring (32) having a variable pitch which gives it a variable characteristic. 4. A device as defined in any one or some of the preceding claims, characterized in that a filter (28) is connected to the holder (14) . 5. A device as defined in any or some of the preceding claims, characterized in that the elements (21) and (23) are made of crude rubber or an elastomer.

Inventors: TORSTENSSON BENGT-ARNE, TORSTENSSON, BENGT-ARNE
Applicants: TORSTENSSON BENGT ARNE, TORSTENSSON, BENGT-ARNE
Application year: 1985
Main classification: G01N1
IPC codes: G01N1