DE29500412U1 - Sampling device for liquid media, in particular liquefied gases - Google Patents

Description

Description

The invention relates to a sampling device for liquid media, in particular liquefied gases, with - an inlet line and

a main container with an inlet and an outlet,

wherein the inlet opening can be connected to the inlet line via at least one switchable valve in a switching position A of the switchable valve, and in a switching position B of the switchable valve for separating the main container from the inlet line, the inlet opening can be connected to the outlet opening via at least one short-circuit line.

The sampling device is particularly intended for use with pressurized liquid media, for example liquefied gases such as liquid gas or the like, but can also be used with other liquid media - for example highly volatile, valuable or toxic.

A sampling device of the type mentioned above for liquid gas with an inlet and an outlet line is known from practice (see Fig. I) ₁ in which the liquid gas from the inlet line is either passed through the main container via the switchable valve in a switching position A of the switchable valve, or is returned directly to the line or container to be monitored in a switching position B of the switchable valve. Depending on the liquid gas throughput and other conditions, the sampling device is either installed directly in a main liquid gas line or - preferably - connected in parallel to such a line as a bypass.

In the switching position B of the switchable valve, which is designed as a four-way tap changeover valve, a so-called container

circuit is formed in which liquid gas flows through the main container (see Fig. 7). After switching the switchable valve to the switch position B, a so-called short-circuit circuit is formed in which the main container and some other parts of the sampling device are decoupled from the flowing medium. The contents of the main container are now available for examination.

When used in practice, the known sampling device shows the following disadvantage: In the switching position B of the switchable valve, i.e. in the so-called short-circuit circuit, the closed liquid system formed from the contents of the main container and the adjacent pipe components is under the high static pressure of the liquid gas. Since the liquid gas no longer flows in this liquid system, a gradual heating of the liquid can lead to an even further increase in pressure, which can damage the sampling device and/or lead to an uncontrolled leakage of the liquid gas. 20

The task is therefore to create a sampling device with improved operational reliability while avoiding the aforementioned disadvantages of the prior art.

The object is achieved according to the invention in that the parts of the sampling device that cannot be connected to the inlet line in the switching position B of the switchable valve can be depressurized via at least one preferably adjustable differential pressure valve into the inlet line and/or into a drain opening.

The suitable insertion of at least one differential pressure valve ensures that, in the event of a pressure increase in the liquid system in the parts of the sampling device that cannot be connected to the inlet line in the switching position B of the switchable valve, no damage to the sampling device according to the invention and no uncontrolled

• · i Φ « ·

The pressurized liquid medium can be released in a controlled manner into the inlet line and/or into a drain opening. An adjustable differential pressure valve is preferably used to adapt the differential pressure at which the differential pressure valve opens to the respective pressure conditions when using the sampling device and the pressure resistance of its respective components.

According to a preferred development of the invention according to claim 2, in the switching position A of the switchable valve, the outlet opening of the main container can be connected to an outlet line and in the switching position B of the switchable valve, the inlet line can be connected to the outlet line to separate the main container from the inlet line and the outlet line, whereby the parts of the sampling device that cannot be connected to the inlet line and/or the outlet line in the switching position B of the switchable valve can be depressurized via at least one preferably adjustable differential pressure valve into the inlet line and/or the outlet line and/or into the drain opening. In this design, the sampling device can be inserted into a main line for the liquid medium to be examined - analogous to the known sampling device - or connected in parallel to it in the form of a bypass.

In this embodiment, the inlet line is preferably provided with an inlet valve and the outlet line with an outlet valve in order to be able to completely disconnect the sampling device from the main liquid line in the event of maintenance, replacement or repair work. If the inlet valve and the outlet valve are closed at the same time, a gradual heating of the liquid in the disconnected sampling device can lead to a pressure increase, which can lead to damage to the sampling device and/or to inconsistent

controlled discharge of the liquid. Depending on the position of the switchable valve, the pressure increase either acts - in switching position A - on the sampling device as a whole, or - in switching position B - separately on the parts of the sampling device that can and cannot be connected to the inlet line and/or the outlet line in switching position B of the switchable valve. It is therefore preferred that all parts of the sampling device that can be separated from the inlet line and the outlet line by closing the inlet valve and the outlet valve can be depressurized via preferably adjustable differential pressure valves into the inlet line and/or the outlet line and/or into the drain opening.

In this way, the operational reliability of the invention described can be further increased.

The further development of the sampling device according to claim 2 can be inserted directly into the line with the liquid medium from which samples are to be taken, provided that no excessively large quantities of liquid flow in the line. In general, and especially with larger liquid flows, it is preferred to connect the sampling device according to claim 2 as a bypass to the main line with the liquid medium. However, the bypass connection requires that at the sampling point - i.e. at the point where the inlet line branches off from the main line - there is a higher pressure in the main line than at the return point - i.e. at the point where the outlet line flows back into the main line. Such a pressure difference between the sampling point and the return point can be generated, for example, by inserting a pressure-reducing component into the main line between the sampling point and the return point.

However, such a pressure-reducing component naturally reduces the flow through the main line or increases

the delivery pressure required to pump a given quantity of liquid.

If the use of such a pressure-reducing component ₄ is not possible or not desired, the pressure in the outlet line must either be increased to at least the pressure level of the return point, for example by inserting an additional pressure pump in the outlet line, or the return to the main line must be dispensed with. However, other applications are also possible in which it is not desired to return the sample liquid flow once it has been taken to the main line; for example, if there is a risk that undesirable contamination of the sample liquid flow could occur when it flows through the sampling device.

In these cases, the further development of the sampling device according to claim 5 can be used advantageously, in which the parts of the sampling device that cannot be connected to the inlet line and/or the drain opening in the switching position B of the switchable valve can be depressurized into the inlet line and/or the drain opening via at least one preferably adjustable differential pressure valve and the switchable valve can be connected either to the inlet line or to the drain opening via at least one further switchable valve. Preferably, the further switchable valve connects the inlet line in a switching position I and the drain opening in a switching position II to the switchable valve, with the other connection being closed. This ensures that the inlet line, regardless of the switching position of the switchable valve, can never be connected directly to the drain opening in order to prevent the sample liquid flow from escaping unhindered into the drain opening.

The further switchable valve can advantageously be designed as a valve combination of two valves, which, for example,

through a mechanical coupling, can only be switched simultaneously.

However, it can also be designed, for example, as a manually, electrically, magnetically, pneumatically or hydraulically operated four-way valve or as another combination of suitably arranged two- or three-way valves, provided that it is ensured that the replacing valves can be switched in a suitable manner.

Analogous to the development of the invention according to claim 4, it is also preferred here according to claim 8 that all parts of the sampling device can be pressure-relieved via preferably adjustable differential pressure valves in the inlet line and/or in the drain opening in order to further increase the operational reliability of this design of the sampling device. The pressure relief preferably takes place via a common pressure relief line in order to keep the structure of the sampling device as simple and space-saving as possible even in this advantageous design.

The drain opening is preferably formed by the outlet opening of a safety pressure relief valve in order to ensure that in the event of a pressure relief of the sampling device, escaping liquid or escaping gas cannot escape unhindered but only when a certain pressure level is exceeded at the drain opening. A further advantage is that, for example, in the event of a leak in one of the differential pressure valves, the liquid or gas escaping from the differential pressure valve cannot constantly escape from the drain opening but can collect in front of the drain opening and then escape in controlled bursts through the safety pressure relief valve.

The pressure at which the pressure relief valve opens is advantageously higher than that normally prevailing in the input power.

In this case, even if one of the differential pressure valves used fails completely, it is not possible for the liquid flow from the inlet line to continuously escape from the safety pressure relief valve.

It is preferred that a drain line is connected to the drain opening in order to be able to direct any liquid or gas escaping from the drain opening out of the sampling device. An exhaust air filter, an exhaust air sensor, a flow meter or similar monitoring, control or safety elements can be inserted into this drain line. The drain line can also open into the inlet line or the outlet line if necessary.

The switchable valve is preferably designed as a four-way valve, as this allows a particularly simple, compact and space-saving design. The four-way valve can be operated manually, electrically, magnetically, pneumatically or hydraulically. However, it can also be replaced by suitably arranged two- or three-way valves if it is ensured that the valves being replaced can be switched in a suitable manner.

5 A transport container can be connected in parallel to the main container. In this way, two separate samples can be obtained at the same time, for example for blind or control analyses. If the main and transport containers are different sizes, the desired size of the liquid sample can be selected by selecting one of the two containers depending on the intended use.

According to a further development of the invention, the main container and/or the transport container are provided with switchable valves in the area of their respective 5 inlet and outlet openings. These valves and also the inlet and/or outlet valves in the inlet and/or outlet line are

Preferably designed as diaphragm valves, as these can only be closed more slowly than ball valves and thus a so-called pressure surge caused by the closing of the valves - which could possibly trigger the opening of the safety pressure relief valve, if present - is prevented.

The valves on the main container and/or the transport container can also be equipped with a safety option in the form of an overpressure release device in order to relieve the pressure in the event of a strong increase in pressure in the main container and/or the transport container, even when the container is removed from the sampling device. This design is particularly useful if the main container and/or the transport container is designed to be removable from the sampling device. The liquid sample obtained can then be easily taken to a laboratory for examination directly inside the main container and/or the transport container without further decanting.

A parallel line can be connected in parallel to the main container. Connecting the main container and/or the transport container and/or the parallel line to the other parts of the sampling device is particularly easy if the main container and/or the transport container and/or the parallel line have self-closing couplings. Removing and replacing the main container and/or the transport container can then be carried out particularly easily, quickly and safely. The parallel line allows the connecting lines between the main container and/or the transport container on the one hand and the switchable valve on the other to be flushed and vented.

If the height of the main container and/or the transport container is adjustable relative to each other, the desired sample quantity can be easily and continuously adjusted by simply adjusting the height of, for example, the transport container relative to the main container. To do this, first

only the main container and the parallel line are filled with the liquid sample and then the switchable valve is moved to the switch position B to form a closed liquid system that encloses the interior of the main container. The connecting lines between the main container on the one hand and the parallel line on the other are then disconnected and the main container is connected to the transport container instead. According to the principle of communicating vessels, the amount of sample that goes from the main container to the transport container can then be easily adjusted by adjusting the height of the transport container relative to the main container. The transport container is then uncoupled by closing its valves and the main container is separated from the transport container again and connected to the parallel line. The transport container then contains exactly the desired and set amount of liquid sample, which can then be checked, for example, by weighing the transport container.
20

Since the sampling device according to the invention is intended in particular for use with pressurized liquids, for example liquefied gases, the sampling device, in particular the main container and/or the transport container, is preferably designed to be pressure-resistant. The sampling device according to the invention has proven itself in test use with liquefied gases, such as so-called liquefied gas and ethylene oxide. If such liquefied gases exit the discharge opening and are depressurized to atmospheric pressure, the liquefied gas evaporates almost instantly. The sampling device according to the invention has also been used advantageously in tests with propylene oxide, which is still liquid at room temperature even when not pressurized.

Further advantageous embodiments of the invention are counter-

- 10 status of the subclaims.

The invention is described in more detail below using three exemplary embodiments, which are explained in more detail in the accompanying drawings. In the drawings:

Fig. 1 shows a first embodiment of a sampling device according to the invention with the switchable valve in the switching position A, 10

Fig. 2 like Fig. 1, but with the switchable valve in the switching position B,

Fig. 3 shows a second embodiment of a sampling device according to the invention with the switchable

Valve in switching position A,

Fig. 4 like Fig. 3, but with the switchable valve in the

Switch position B,
20

Fig. 5 shows a third embodiment of an inventive

sampling device with the switchable

Valve in switching position A,

Fig. 6 like Fig. 5, but with the switchable valve in switching position B,

Fig. 7 shows a known sampling device according to the preamble of claim 1.

Fig. 7 shows a known sampling device 100 according to the preamble of claim 1. The known sampling device 100 for liquid gas has an inlet line 101 and an outlet line 102. The liquid gas is fed via a four-way valve switchover device 103 and a pressure hose connection 104, 105 either through a stainless steel main container 106 or directly into the

Line or returned to the container to be monitored. The flowing product quantity is monitored in both positions of the four-way tap changeover valve 103 with a flow meter 107 and can be adjusted using a control valve 108. In front of the valve opening A of the four-way tap changeover valve 103 there is a nozzle 109 for limiting the flow rate. The main container 106 can be connected using self-closing couplings 110, 111 and the flexible pressure hoses 104, 105. The flexible pressure hoses 104, 105 are made of polytetrafluoroethylene PTFE with a stainless steel braided sheath and are antistatic. Fittings and line connectors are made of stainless steel. The known sampling device from Fig. 7 can be mounted either on a wall mounting panel or in a housing 117. The inlet 101 and outlet lines 102 can be closed with shut-off valves 113, 114.

Two switching positions are possible for the four-way tap changeover valve 103. In the switching position shown in Fig. 7, the valve opening A is connected to B and the valve opening C to D. In this switching position, a so-called large or container circuit is formed in which the liquid gas flows through the main container 6, as shown in Fig. 7. Depending on the liquid gas throughput and other conditions, the sampling device 100 is either installed directly in a liquid gas line or, preferably, connected in parallel as a bypass to such a line. After switching the four-way tap changeover valve to its second switching position (not shown), the valve opening A 0 is connected to C and the valve opening B to D. In this switching position, a so-called small or short circuit circuit is formed in which the main container 106, the pressure hoses 104, 105 and the line section 112 are disconnected from the flowing medium. The valves 108, 113 can now be closed, the self-sealing couplings 110, 111 released and the filled main container 106 removed. The filled main container 106 is preferably filled by another main

container 106 is replaced, whereupon the sampling device 100 - after connecting the new sample container 106 and switching the four-way tap changeover valve 103 - is again available for a new sampling. 5

However, the known sampling device according to Fig. 7 shows some disadvantages when operated in practice.

Thus, the closed liquid system formed in the short-circuit circuit essentially from the components 104, 105, 106, 112 is under the high static pressure of the liquid gas. Since the liquid gas no longer flows in this liquid system, a gradual heating of the liquid can lead to an even further increase in pressure, which can lead to damage to the sampling device 100 and/or an uncontrolled escape of the liquid gas.

Such a pressure increase can also occur if the inlet valve 113 and the outlet valve 114 are closed at the same time, whereby the pressure increase either - in the setting for the container circuit shown in Fig. 7 - affects the entire sampling device 100, or - in the switch position for the short-circuit circuit - is limited to the line components 115 and 116 and the components connected to them. In this case too, there is no protection of the sampling device 100 against damage and/or uncontrolled leakage of the liquid gas.

The sampling device according to the invention provides a remedy here. The first embodiment 1 of Figs. 1 and 2 also has a four-way tap changeover valve 7, which can be switched between two switching positions - switching position A for the so-called large or container circuit (Fig. 1) and switching position B for the so-called small or short-circuit circuit (Fig. 2).

In switch position A "tank circuit" of the four-way valve

changeover valve 7 (Fig. 1), the liquid gas flows via the inlet line 2 and the inlet valve 3 into a pipe 6, into which a flow limiter 4 and a differential pressure valve 5 acting as a check valve are inserted. The pipe 6 opens into a valve opening A of the four-way valve changeover device 7. The liquid gas leaves the four-way valve changeover valve 7 via the valve opening C and flows via the pressure hose 8, the self-closing coupling 9a and the valve 10 into the main container 11. It leaves the main container 11 again via the valve 12, the self-closing coupling 13a and the pressure hose 14 in order to re-enter the four-way valve changeover valve 7 via the line 15 and the valve opening D. It can then leave the sampling device 1 again via the valve opening B, the flow meter 17, the pipe 18, the outlet valve 19 and the outlet line 20. The entire sampling device 1 can - analogously to the known sampling device 100 - be inserted into a liquid gas line or connected in parallel to it in the form of a bypass.

The pipeline 15 is coupled to a pressure measuring device 16 so that the pressure in the pipeline 15 can be checked at any time.

The pipe 6 is connected to an adjustable differential pressure valve 23 and a pipe 24 with an adjustable safety pressure relief valve 25. If the pressure in the pipe 6 increases significantly, the pressure can be relieved via the differential pressure valve 23 and the safety pressure relief valve 25. This can occur, for example, if the inlet valve 3 and the outlet valve 19 are closed together.

In Fig. 2, the sampling device 1 is shown in the second switch position B of the four-way valve switching device 7, in which a short circuit is formed. The liquid gas enters via the inlet line 2, the inlet valve

• · &igr; ·

valve 3, the line 6 and the components built into it, the flow rate limiter 4 and the differential pressure valve 5 acting as a check valve, into the valve opening A of the four-way valve changeover valve 7. It leaves the four-way valve changeover valve 7 via the valve opening B and then flows out of the sampling device 1 again via the flow meter 17, the pipe 18, the outlet valve 19 and the outlet line 20. A second liquid system S, essentially made up of the pressure hose 8, the main container 11, the pressure hose 14 and the pipe 15, is decoupled from the short-circuit circuit. However, the decoupling is not complete: there is instead a further pipe 22, which is connected at one end via an adjustable differential pressure valve 21 to the pipe 15 of the liquid system S and at the other end to the pipe 24. The function of this pressure relief line 22, the differential pressure valve acting as a check valve 5, the differential pressure valves 21, 23 and the safety pressure relief valve 25 are explained in more detail below using a specific example.

The pressure with which the components of the sampling device 1 can be loaded is, for example, 100 bar. The differential pressure valves 21, 23 are set to a pressure difference of 1.5 bar. The safety pressure relief valve 25 is set to an opening pressure of 80 bar. The pressure of the liquid gas is 50 bar.

If the four-way valve changeover valve 7 is in the switch position A for the container circuit (Fig. 1), a pressure of about 50 bar prevails in the entire sampling device 1. The pressure can be read on the pressure gauge 16. If the inlet valve 3 and the outlet valve 19 are now closed together, the pressure within the entire sampling device 1 gradually increases. The pressure differences in the individual parts of the sampling device cannot exceed 1.5 bar, since in this

If the differential pressure valves 5, 21, 23 open and the pressure differences can equalize. The highest static pressure in the sampling device 1 is therefore always present at the safety pressure relief valve 25 - up to a difference of max. 1.5 bar. At a pressure of 80 bar, the safety pressure relief valve 25 opens and the pressure in line 24 and the line 26 connected to it is relieved. The other parts of the sampling device 1 are then also relieved of pressure via the differential pressure valves 5, 21 and 23 which then open. The outlet of the safety pressure relief valve 25 can simply open outwards - as shown in Fig. 1, but it can also be connected, for example, to the outlet line 20 or to a downstream filter element.
15

If the four-way valve switching device 7 is in position B for the short-circuit circuit (Fig. I) ₁ , then in addition to the short-circuit circuit with the inlet 2 and outlet line 20, there is a second, closed liquid system S essentially made up of the pressure hose 8, the main tank 11, the pressure hose 14 and the pipe 15. If the inlet valve 3 and the outlet valve 19 are closed simultaneously, the short-circuit circuit can be relieved of pressure again, as previously described, via the differential pressure valves 5 and 23, via the pipe 24 and the safety pressure relief valve 25 in the event of an excessive pressure increase. For the fluid system S, pressure relief takes place via the differential pressure valve 21, the pressure relief line 22, the line 24 and the safety pressure relief valve 25 as soon as the pressure in the pipe 24 and in the pipe 22 connected to it is at least 1.5 bar below the pressure in the fluid system S and this pressure exceeds 80 bar. The differential pressure valves 21 and 23 and the differential pressure valve 5 acting as a check valve prevent medium from flowing back from the fluid system S or from the outlet lines 18 and 20 into the inlet lines 2 and 6.

The removal of the main container 11 with the liquid sample can take place in the usual way as with the known sampling device 100 (see Fig. 2). The new sampling device 1 can also be mounted on a wall mounting panel or in a protective cabinet 26. All fittings and line connectors are preferably made of stainless steel, as with the known sampling device 100. The structure of the pressure hoses 8, 14 is preferably the same as with the known sampling device 100.

Figures 3 and 4 show a second embodiment 200 of the sampling device according to the invention. In Figure 3, the sampling device 200 is shown in the switching position A of the switchable valve 207, which is designed as a four-way valve. In this switching position A, a so-called container circuit is formed, analogous to the first embodiment 1 of Figure 1. In the switching position B of the switchable valve 207 shown in Figure 4, a so-called short-circuit circuit is formed - analogous to the first embodiment 1 of Figure 2. In the switching position B of the switchable valve 207 designed as a four-way valve, the liquid system S, which essentially consists of the connecting lines 232, the main container 211 and the parallel line 233 or the transport container 234, is completely closed off from the inlet line 202 and the outlet line 220.

The functionality of the second embodiment 200 of Figs. 3 and 4 largely corresponds to that of the first embodiment 1 of Figs. 1 and 2. The differences between the two embodiments will therefore be discussed in detail below.

In the sampling device 200, the main container 211 is fixedly arranged in the sampling device 200. Instead, the sampling device 200 has an additional removable transport container 234. The main container 211 can be connected to the sample via flexible, detachable lines 208,

214 a parallel line 233, which is permanently connected to the outlet opening 211b of the main container 211, or the transport container 234 can be connected in parallel. The parallel line 233 and the transport container 234 each have self-closing couplings 23 8, 23 9, 238a, 23 9a. The flexible lines 208, 214, which are designed as plastic lines with a metal braided sheath, are correspondingly equipped with self-closing coupling counterparts 209, 213. Furthermore, the transport container 234 is provided with switchable valves 235, 23 6 in the area of its inlet and outlet openings. The transport container 234 is arranged in the sampling device 200 so that its height can be adjusted relative to the main container 211.

The sampling process with regard to the switchable valve 207 is the same as in the first embodiment 1. The four-way valve 207 is initially in the switch position A shown in Fig. 3. The liquid medium can then, as shown in Fig. 3, flow from the inlet line 202 through the main container 211 and through the parallel line 233 connected in parallel to the main container 211 via the flexible lines 208, 214 in order to return to the outlet line 220. If the switchable valve 207 is moved to the switch position B, the above-mentioned closed liquid system S comprising the contents of the main container 211 is formed (see Fig. 4). Then the self-closing coupling counterparts 209, 213 of the flexible lines 208, 214 are detached from the self-closing couplings 238, 239 of the parallel line 233 and instead inserted into the self-closing couplings 238a, 239a of the transport container 234 (see Fig. 4). The transport container 234, which is generally empty at the beginning of the measurement or only filled with a small residual amount of the medium to be examined in liquid and/or gaseous form, is thus connected to the main container 211 - if necessary after opening its valves 235 and 236. A certain proportion of the contents of the main container 211 and the main container

· · I

ter 211 into the interior of the transport container 234. By adjusting the height of the transport container 234 with respect to the main container 211, the amount of liquid sample transferred from the main container 211 into the transport container 234 can be selected almost completely freely, since according to the principle of communicating vessels, the same liquid level is established in the main container 211 and in the transport container 234.

After setting the desired amount of liquid sample in the transport container 234, the valves 235, 236 are closed, the flexible lines 208, 214 are detached from the self-closing couplings 238a, 239a and reconnected to the parallel line 233. The transport container 234 can now be removed from the sampling device 200 with its set liquid sample. The amount of liquid sample obtained can thus easily be adapted to the desired purpose of the liquid sample.

Furthermore, the sampling device 200 has a drain line 231, which is connected to the drain opening 230 formed by the outlet opening of a safety pressure relief valve 225. For example, a filter for escaping liquid or escaping gas and/or a corresponding measuring sensor can be connected to the drain line 231. In addition, the sampling device 200 has a control valve 242 for controlling the flow of the liquid medium through the sampling device 200.

0 The sampling device 200 has proven itself to be very effective in tests with liquefied gases, such as so-called liquid gas and ethylene oxide. If such liquefied gases escape from the safety pressure relief valve 225 and are released to atmospheric pressure in the discharge line 231, the liquefied gas evaporates almost instantly. The sampling device 200 is also suitable for tests with propylene oxide, which is

·

- 19 -

door is still liquid even when not pressurized. Regarding the remaining parts of the sampling device 200, in particular regarding the arrangement and function of the differential pressure valves 205, 221 and 223, reference is made to the description of the embodiment 1 of Figures 1 and 2.

Figures 5 and 6 show a third embodiment 3 00 of the sampling device according to the invention. The sampling device 3 00 is not intended for insertion into a liquid line or as a bypass to such a main liquid line. Accordingly, the sampling device 3 00 only has an inlet line 302 and a drain opening 330, which is formed by the drain opening of a safety pressure relief valve 225 and to which a drain line 331 is connected.

The sampling device 300 is again - analogous to the sampling device 200 - equipped with a main container 311, a parallel line 333 and a transport container 334. In this respect, reference is made to the description of the second embodiment 200 of Figs. 3 and 4.

Instead of a simple inlet valve in the inlet line 302, the sampling device 300 has a further switchable valve 341, which is designed in the form of a valve combination of two three-way valves that can only be switched simultaneously by means of a mechanical coupling 341a. The valve openings 3 and 6 of the valve combination 341 are permanently closed by corresponding seals.

At the beginning of sampling, the switchable valve 3 07 is in the switch position A and the additional switchable valve 341, designed as a valve combination, is in the switch position I (see Fig. 5). In these switch positions A and I of the two switchable valves 3 07 and 341, there is a

- 20 -

connection from the inlet line 3 02 via the valve openings 1 and 2 of the valve combination 341, the line 306, the valve openings A and C of the four-way valve 3 07, the connecting lines 332, main container 311 and parallel lines 333, the valve openings D and B of the switchable valve 307 and the line 318 to the valve opening 4 of the valve combination 341. The connection between the valve opening 4 and the valve opening 5 of the valve combination 341 is, however, closed (cf. Fig. 5). Accordingly, any liquid or gas still contained in the sampling device 3 00 cannot escape via the line 343 into the drain line 331, but is compressed by the pressure prevailing in the inlet line 3 02 in front of the valve opening 4 of the valve combination 341 in the line 318. This can, for example, B. it could be liquid with which the sampling device 300 is still filled from the last sampling process. It could also be gas bubbles that have come about through evaporation of the liquid medium. Since the transport container 234 is usually filled with a chemically inert gas such as nitrogen or argon after the liquid sample has been taken in the testing laboratory and then reinserted into the sampling device 300, it could also be, for example, gas bubbles of such chemically inert gases. Furthermore, the sampling device 300 is preferably also filled with a chemically inert gas when it is first assembled and connected to the inlet line 302 for the first time, so that a controlled removal of gas bubbles must also be ensured when the sampling device 300 is first connected.
30

In order to be able to discharge the liquid and/or gas quantities in line 318 in front of valve opening 4 of valve combination 341 in a controlled manner, valve combination 341 is switched back and forth several times between its switching position I and its switching position II. The mechanical coupling 341a of the two three-way valves forming valve combination 341 ensures that at no time is a

continuous connection path from the inlet line 302 into the line 343 and thus into the drain line 331 exists. Rather, the connection between the valve openings 1 and 2 of the valve combination 341 is always open when the connection between the valve openings 4 and 5 is closed, and vice versa. In this way, the amount of liquid and/or gas present in front of the valve opening 4 of the valve combination 341 in the line 318 can be released in a cyclical and controlled manner via the line 343 into the drain line 331 until the sampling device 3 00 has been flushed to the desired extent, contains new liquid medium from the inlet line 3 02 and the actual sampling process can begin.

Regarding the other construction of the sampling device 300, in particular regarding the operation of the four-way valve 307, the parallel line 333, the transport container 234 and the arrangement and operation of the differential pressure valves 305, 321 and 323, reference is made to the description of the embodiments 1 and 200 of Figures 1-4.

- 29 -

List of reference symbols

&igr;, 20 13, 200, 300 ·
• *
•
•
&bull; Sampling device 5 2, 13a 202, 302 Input line 3, 14, 203 Input valve i1 4, 15, 204, 304 Flow limiters, especially as 25 16, Nozzle formed 5, 17, 205, 305 Differential pressure valve 10 6, 18, 206, 306 Line 7, 19, 207, 307 switchable valve, especially as a four 20, way tap trained 8th, 30 21, 208, 308 flexible cable 8a, 22, 208a , 308a Line 15 9, 23, 209, 309 self-closing coupling counterpart 9a 24, self-closing coupling 10 25, Valve 11, 55 30, 211, 311 Main tank 12 231, Valve, especially as a control valve made of 32, educated 213, 313 self-closing coupling counterpart self-closing coupling 214, 314 flexible cable 215, 315 Line 216, 316 Pressure gauge 217, 317 Flowmeter 218, 318' Line 219 Output valve i1 220 Output line 221, 321 Differential pressure valve 222, 322 Pressure relief line 223, 323 Differential pressure valve 224, 324 Line 225, 325 Safety pressure relief valve 230, 330 Outlet opening . 331 Drain line 232, 332 Connecting cables .< ···. .....
··· . : : : : :.:. :

10

233, 333 234, 334 235, 335 236, 336 238, 338 238a, 338a 239, 339 239a, 339a 341 341a 242, 342 343

- 30 -

Parallel line

Transport container valve

Valve

self-closing coupling self-closing coupling self-closing coupling self-closing coupling

additional switchable valve, especially

designed as valve combination mechanical coupling control valve

Line

Claims (28)

- 22 - Addresses 1. Sampling device for liquid media, in particular liquefied gases, with an input line and - a main container with an inlet opening and an outlet opening, wherein the inlet opening can be connected to the inlet line via at least one switchable valve in a switching position A of the switchable valve is, and in a switching position B of the switchable valve for separating the main tank from the inlet 0 gang line the inlet opening over at least a short-circuit line can be connected to the outlet opening , characterized in that the parts of the sampling device (1, 200, 300) that cannot be connected to the inlet line (2, 202, 302) in the switching position B of the switchable valve (7, 207, 307) can be relieved of pressure via at least one preferably adjustable differential pressure valve (21, 221, 321) into the inlet line (2, 202, 302) and/or into a drain opening (30, 230, 330). 2. Sampling device according to claim 1, characterized in that in the switching position A of the switchable valve (7, 207) the outlet opening (11b, 211b) of the main - 23 - holder (11, 211) is connectable to an output line {20, 220) and in the switching position B of the switchable valve (7, 207) for separating the main container (11, 21I) ₁ from the inlet line (2, 202) and the outlet line (20, 220) the input line (2, 202) can be connected to the output line (20, 220), wherein in the switching position B of the switchable valve (7, 207) the input line (2, 202) and/or the output line (20, 220) parts of the sampling device (1, 200) can be depressurized via at least one preferably adjustable differential pressure valve (21, 221) into the inlet line (2, 202) and/or into the outlet line (20, 220) and/or into the drain opening (30, 230) are. 3. Sampling device according to claim 2, characterized in that the inlet line (2, 202) is provided with an inlet valve (3, 203) and the outlet line (20, 220) is provided with an outlet valve (19, 219). 4. Sampling device according to claim 3, characterized in that all parts of the sampling device (1, 200) which can be separated from the inlet line (2, 202) and the outlet line (20, 220) by closing the inlet valve (3, 203) and the outlet valve (19, 219) can be depressurized via preferably adjustable differential pressure valves (5, 21, 23, 205, 221, 223) into the inlet line (2, 202) and/or into the outlet line (20, 220) and/or into the drain opening (30, 230). 5. Sampling device according to claim 1, characterized in that which in the switching position B of the switchable valve (307) is not connected to the input line (302) and/or - 24 - the parts of the sampling device (300) that can be connected to the drain opening (330) can be depressurized via at least one preferably adjustable differential pressure valve (321) into the inlet line (302) and/or into the drain opening (330) and the switchable valve (307) can be connected via at least one further switchable valve (341) either to the inlet line (302) or to the drain opening (330).
10 6. Sampling device according to claim 5, characterized in that the further switchable valve (341) connects the inlet line (302) to the switchable valve (307) in a switching position I and the drain opening (330) in a switching position II, the other connection being closed. 7. Sampling device according to claim 5 or 6, characterized in that the further switchable valve (341) is designed as a valve combination (341) of two valves which can be switched exclusively simultaneously, for example by a mechanical coupling (341a). 8. Sampling device according to one or more of claims 5-7, characterized in that all parts of the sampling device (300) can be pressure-relieved via preferably adjustable differential pressure valves (305, 321, 323) into the inlet line (302) and/or into the drain opening (330). . Sampling device according to claim 4 or 8, characterized in that the pressure relief takes place via a common pressure relief line (22, 24, 222, 224, 322, 324). 10. Sampling device according to one or more of the preceding claims, characterized in that the - 25 - Drain opening (3 0, 230, 33 0) is formed by the outlet opening of a safety pressure relief valve (25, 225, 325). 11. Sampling device according to claim 10, characterized in that the pressure at which the safety pressure relief valve (25, 225, 325) opens is higher than the pressure normally prevailing in the inlet line (2, 202, 302).
10 12. Sampling device according to one or more of the preceding claims, characterized in that a drain line (231, 331) is connected to the drain opening (230, 330). 13. Sampling device according to one or more of the preceding claims, characterized in that the switchable valve (7, 207, 307) is designed as a four-way valve (7, 207, 3 07). 14. Sampling device according to one or more of the preceding claims, characterized in that a parallel line (233, 333) can be connected in parallel to the main container (211, 311). 15. Sampling device according to claim 14, characterized in that the parallel line (223, 323) is connected to the main container (211, 311). 0 16. Sampling device according to one or more of the preceding claims, characterized in that a transport container (234, 334) can be connected in parallel to the main container (11, 211, 311). 17. Sampling device according to claim 16, characterized in that the main container (211, 311) and/or the transport container (234, 334) are arranged relative to each other in - 26 of the height are adjustable. 18. Sampling device according to one or more of the preceding claims, characterized in that the main container (11, 211, 311) and/or the transport container (234, 334) are provided with switchable valves (10, 12, 235, 236, 335, 336) in the region of their respective inlet and outlet openings. 19. Sampling device according to one or more of the preceding claims, characterized in that the main container (11, 211, 311) and/or the transport container (234, 334) can be removed from the sampling device (1, 200, 300). 20. Sampling device according to one or more of the preceding claims, characterized in that the main container (11, 211, 311) and/or the transport container (234, 334) and/or the parallel line (233, 334) for connection to the other parts of the sampling device (1, 200, 300) has self-closing couplings (9a, 13a, 238, 239, 238a, 239a, 338, 339, 338a, 339a). 21. Sampling device according to one or more of the preceding claims, characterized in that the connecting lines between the main container (11, 211, 311) and/or the transport container (234, 334) and/or the parallel line (233, 333) on the one hand and the switchable valve (7, 207, 307) on the other hand are detachable and at least partially flexible, in particular as flexible lines (8, 14, 208, 214, 308, 314) made of plastic with a metal braided sheath and self-closing coupling counterparts (9, 13, 209, 213, 309, 313). 22. Sampling device according to one or more of the preceding claims, characterized in that the - 27 - Sampling device (1, 200, 300), in particular the main container (11, 211, 311) and/or the transport container (234, 334) is designed to be pressure-resistant. 23. Sampling device according to one or more of the preceding claims, characterized in that the main container (11, 211, 311) and/or the transport container (234, 334) is provided with a safety pressure relief valve.
10 24. Sampling device according to one or more of the preceding claims, characterized in that the sampling device (1, 200, 3 00) has a flow limiter, for example a nozzle (4, 204, 304) for quantitatively limiting the flow of the liquid medium through the sampling device (1, 200, 3 00). 25. Sampling device according to one or more of the preceding claims, characterized in that the Sampling device (1, 200, 3 00) has a control valve (12, 242, 342) for regulating the flow of the liquid medium through the sampling device (1, 200, 3 00).
25 26. Sampling device according to one or more of the preceding claims, characterized in that the sampling device (1, 200, 300) has a flow meter (17, 217, 317) for controlling the flow of the liquid medium through the sampling device (1, 200, 300). 27. Sampling device according to one or more of the preceding claims, characterized in that the sampling device (1, 200, 300) comprises a pressure measuring device (16, 216, 316) for measuring the pressure in the sampling device (1, 200, 300), in particular in the main container - 28 (11, 211, 311) prevailing pressure. 28. Sampling device according to one or more of the preceding claims, characterized in that the sampling device (1, 200, 300) can be mounted on a wall panel and/or in a housing (26).