SUBSEQUENT VALVES

Technical field

[0001] The present invention relates generally to a coupling and coupling part for transfer of liquified gas wherein the coupling part comprise dual subsequent valves.

Background art

[0002] In cryogenic applications variations in temperature could quickly become dangerous, especially if liquified gases reaches boiling temperatures causing them to expand rapidly. One example is Liquid hydrogen (LH2) that at atmospheric pressure needs to be maintained below approximately -250°C for it to stay in a liquid state. In general, storing gas in a liquid state requires less space, the most common example is that if you boil water in a closed container pressure will be built within the container. The same applies for liquified gases, however most of them vaporize long before outdoor or indoor temperatures. Thus, if subjected to temperatures of the surrounding area they would rapidly expand creating dangerous pressure.

[0003] When transferring liquified gas, couplings are one critical and vulnerable component where thermal bridges and dead spaces containing for example air could provide dangerous temperature variations. In prior art different solutions for transferring liquified gases are well known, for example one common solution is for fuel such as Liquefied Natural Gas, LNG, to be transferred from a fuel station to a vehicle. Other examples are liquified gases being transferred to/from ships, vehicles, or stationary tanks. In most applications such transfer of liquified gases requires at least one coupling or nozzle for connection and disconnection. As known in the art liquified gases requires less volume for storage, are safer to store, and safer to transfer in the liquid state than in its corresponding gas form.

However, the low boiling point of useful gases requires many liquified gases to be stored at low temperatures. For example, in atmospheric pressure LNG is condensed to liquid at temperatures below approximately -160°C, liquid hydrogen, LH2, at temperatures below approximately -250°C, and nitrogen for liquid nitrogen, LN2, approximately -195°C.

[0004] Liquified gases are used for different purposes but independent of the purpose efficiency and safety are important factors. To provide one out of many examples, liquified gases may be used as fuel and need to be transferred from a fueling station to for example a truck. Although the transfer as such is well known in the art there are drawbacks in the art reducing the efficiency and possible occupancy level of for example a fueling station.

Summary of invention

[0005] An object of the present solution is to provide a safe coupling part for liquefied gas couplings wherein the requirement for dual safety barriers is achieved without the drawbacks of the prior art.

[0006] Another object of present solution is to provide a coupling part that may be purged without contact with for example the storage tank at the other end of the coupling.

[0007] Yet another object is to provide a solution wherein pressure building from raising temperatures within the coupling part may be handled without gas being vented to the outside atmosphere.

[0008] Thus, the solution relates to a coupling part for a liquefied gas coupling. The coupling part comprises a housing and a flow path for liquefied gas, a first valve and a second valve arranged subsequent of each other in the flow path. A first chamber is formed between the first and second valve, and the first valve is arranged at a first distance from the second valve such that the first valve actuates the second valve if actuated longer than the first distance.

[0009] It is one advantage that the first valve is arranged at a first distance from the second valve such that the first valve actuates the second valve only if actuated longer than the first distance. This enables effective and safe purging of the coupling wherein the first chamber can be purged without opening up the entire coupling. Purging is the processes of controlling which gases that are present in a gas transfer system, this could for example be conducted by passing gas through their interiors of for example a coupling to eliminate the risk of contamination. This helps prevent unwanted reactions and ensures that only the desired gas is present within the coupling.

[0010] According to an embodiment the first valve is spring-loaded towards a first valve seat surface and the second valve is spring-loaded towards a second valve seat surface.

[0011 ] It is one advantage that the spring-loaded valves enable easy mechanical operating of the coupling. Another advantage is that when the coupling is in a closed state, gas trapped within the first chamber might be vented into the for example the tank part of the coupling via the second chamber. If excessive pressure is built within the first chamber, the second valve will spring backwards opening the seal towards the valve seat and allow for brief liquid communication between the first and second chambers. Thus, there is no risk of high pressure within the first chamber if for example the temperature of gas trapped within increases. However, even if venting of high pressure is enabled, in the closed state both the first and second valves seals towards the valve seats of the coupling creating a dual barrier between the atmosphere and the tank part of the transfer system.

[0012] According to an embodiment the first and second valves are springloaded in the opposite direction of a flow direction of the flow path.

[0013] It is one advantage that the bias in the spring-load is in the opposite direction of the flow direction. Thus, when the coupling is closed there is no risk of increasing pressure within neither the tank nor the chambers being vented out into the atmosphere.

[0014] According to an embodiment the stroke length between an open and closed position of the first valve is longer than the stroke length between an open and closed position of the second valve. [0015] It is one advantage that the stroke length between the closed and open positions in one embodiment is shorter for the second valve. The reason for this is that the first valve is partly actuated to the purge state before the second valve is actuated.

[0016] According to an embodiment the first valve is arranged to open partly when actuated the first distance

[0017] According to an embodiment the first valve is arranged to open fully when actuated a second distance.

[0018] According to an embodiment the first chamber comprises a first wider section and the coupling part further comprise a second chamber with a second wider section. The first wider section is arranged further from the first valve seat surface than the distance between the second wider section and the second valve seat surface.

[0019] Another advantage with one embodiment is that the distance between a closed and fully open valve could be changed based on the form of the chambers.

[0020] According to an embodiment each of the first and second valves comprises a valve tip, a valve stem, and a valve head, wherein the valve stems is arranged pointing in the same direction and the valve tip of the first valve is arranged to engage the valve head of the second valve to actuate the second valve.

[0021] According to an embodiment the coupling part is adapted to be coupled to a second coupling part, and the first valve is actuated when the coupling part is coupled to a second coupling part.

[0022] According to an embodiment a valve tip of the first valve act upon the valve head of the second valve actuating the second valve.

[0023] According to an embodiment each of the first and second valves are arranged to restrict the flow path. [0024] According to an embodiment a first open position, also called the purging state or a first locking position, wherein the first valve is at least partly opened and the second valve is closed allowing liquid communication from a second coupling part to the first chamber but preventing liquid communication to the second chamber, thus preventing liquid communication through the valve arrangement but enabling purging of the first chamber.

[0025] According to an embodiment a second open position, also called the transfer position or second locking position, wherein the first valve is open and the second valve is open, thus allowing liquid communication from a second coupling part to the first chamber, through the second chamber, thus allowing for liquefied gas to flow through the coupling.

[0026] According to an aspect in a coupling part for a liquefied gas coupling, the coupling part comprises a housing, a flow path for liquefied gas, a first valve, and a second valve. The first and second valves are arranged subsequent of each other in the flow path and the first valve is arranged at a first distance from the second valve, wherein the following steps are performed:

- actuating the first valve a first distance opening a fluid connection to a first chamber, and

- actuating the first valve beyond the first distance such that the first valve engages with the second valve actuating the second valve establishing a fluid connection through the flow path.

[0027] According to an aspect of purging a valve arrangement comprising a first valve and a second valve arranged subsequently in a flow path of the liquefied gas coupling, wherein the valve arrangement is purged by actuating the first valve to a position that is at least partly open thus allowing a first chamber to be purged.

[0028] According to an aspect a valve arrangement is arranged in a coupling part for a liquefied gas coupling. The valve arrangement comprises a first valve and a second valve each comprising a valve tip, a valve stem, and a valve head. The first and second valves are arranged subsequently in a flow path for liquefied gas with the valve stems pointing in the same direction and a space is formed between the first and second valves.

[0029] According to an embodiment a valve arrangement for a liquefied gas coupling is provide. The valve arrangement is arranged in a first coupling part and adapted to be actuated by a second coupling part from a closed to an open stage, wherein the valve arrangement comprise a first valve and a second valve, arranged subsequently in a flow path for liquefied gas, characterized in that each of the first and second valves are arranged to restrict the flow path, and in that the first valve is arranged to be actuated until at least a partly opened stage before the second valve is actuated.

Brief description of drawings

[0030] The invention is now described, by way of example, with reference to the accompanying drawings, in which:

[0031] Fig. 1 illustrates a coupling part comprising a first and second valve, wherein both valves are closed.

[0032] Fig. 2 illustrates magnifications of the embodiment as shown in Fig. 1 .

[0033] Fig. 3 illustrates a coupling part coupled to a second coupling part, wherein the first valve is partly open and the second valve is closed.

[0034] Fig. 4 illustrates magnifications of the embodiment as shown in Fig. 3.

[0035] Fig. 5 illustrates a coupling part coupled to a second coupling part, wherein the first and second valves are open.

[0036] Fig. 6 illustrates magnifications of the embodiment as shown in Fig. 5.

[0037] Fig. 7 illustrates a coupling with a first and second coupling part.

Description of embodiments

[0038] In the following, a detailed description of the different embodiments of the invention is disclosed under reference to the accompanying drawings. All examples herein should be seen as part of the general description and are therefore possible to combine in any way of general terms. Individual features of the various embodiments and aspects may be combined or exchanged unless such combination or exchange is clearly contradictory to the overall function of the device or method.

[0039] Figure 1 illustrates an embodiment of the coupling part 1 comprising a housing 3. The first 11 and second 12 valves are in figure 1 illustrated as poppet valves arranged subsequently after each other in the flow path 21 . The flow path 21 is arranged to transport liquefied gas but could also be used for other fluids and/or gases. It is understood that other forms of valves could be used within the scope of the solution of the appended claims.

[0040] The first valve 11 is arranged at a first distance L from the second valve 12 such that upon actuation of the first valve 11 the flow path 21 is opened allowing liquid communication into the first chamber 11a before the first valve 11 abuts the second valve 12. Thus, no liquid communication between the first chamber 11a and the second chamber 12a is established before the first valve 11 is actuated past the point where it abuts the second valve 12, i.e. past the length of the first distance L. This is further illustrated in figure 3.

[0041] The coupling part 1 could be part of a transfer system wherein transfer of for example LNG takes place. The second chamber 12a is in direct fluid connection with one side of the transfer system, it could for example be a storage tank or a tank within a vehicle such as a truck, lorry, or any other vehicle. As illustrated in figure 1 the second chamber 12a in one embodiment has another shape than the first chamber 11a. The reason for this is that it enables the second valve 12 to have a shorter working distance, or stroke length, than the first valve 11 in order for the valve to reach a fully open position. The dimension correlates to the first distance in order to ensure the flow in the coupling part 1. In one embodiment the piston travel 2 to 3 mm for before touching the second valve 12, however in different embodiments this might be anywhere from 1 mm and upwards. The state where the first valve 11 is actuated and the second valve 12 still closed is called a purging position, this is further illustrated in figures 3 and 4. Figure 1 illustrates a coupling part 1 wherein the first 11 and second 12 valves are closed. Further, the coupling part 1 as illustrated in figure 1 isn’t engaged to any other part of a coupling 2. The coupling part 1 is illustrated with an opening for receiving a second part of the coupling 2.

[0042] Figure 1 further illustrates each of the first 11 and second 12 valves comprises a valve tip 111 a, 112a, a valve stem 111 b, 112b, and a valve head 111c, 112c, wherein the valve stems 111b, 112b are arranged pointing in the same direction and the valve tip 111a of the first valve is arranged to engage the valve head 112c of the second valve 12 to actuate the second valve 12.

[0043] Figure 2 illustrates two magnifications of the coupling part 1 as illustrated in figure 1 , i.e. in a state wherein the first 11 and second 12 valves are closed. In figure 2 the first distance L is clearly illustrated as a gap between the valve tip 111a of the first valve 11 and the valve head 112c of the second valve 12.

However, different implementations are possible in different embodiments. It is also seen how the first valve 11 in a closed state seals against a first valve seat surface 32. The seals for the first 11 and second 12 valves could for example be annular seals arranged around the valve heads. Further, it is illustrated how the first valve 12 seals against the second valve seat surface 33.

[0044] Figure 3 illustrates the coupling part 1 partly connected in a coupling 2, this position is also called the purge position. In this position, a third valve 22 arranged in a mating part of the coupling 2 keep the first valve 11 in a partly open position providing liquid communication to the first chamber 11a. The first valve 11 has been actuated a short distance that is shorter or equivalent to the first distance L. Although the third valve 22 actuates the first valve 11 in this embodiment, other solutions might be implemented in accordance with the appended claims.

[0045] Figure 4 illustrates two magnifications of the coupling part 1 as illustrated in figure 3 in a state wherein the first valve 11 is partly open and the second valve 12 is closed. As illustrated, the first distance L is reduced or eliminated and the valve head 111 c of the first valve 11 no longer seals against the first valve seat surface 32, the valve head 112c of the second valve 12 still seals towards the second valve seat surface 32, thus enabling purging of the coupling. This position is also called a purge position and as seen in figure 3 the first valve 11 is partly open and the second valve 12 is closed. In this position the first chamber 11a may be purged by flushing for example liquefied gas into the first chamber 11a. When the first chamber 11a is clean and at a temperature that allows for transfer of liquefied gas the coupling could be actuated to the second locking position as illustrated in figure 5.

[0046] Figure 5 illustrates the coupling part 1 connected to a second coupling part 2 and in a second locking position. This position is also called a transfer position and as seen in figure 5 the first valve 11 is open and the second valve 12 is open, thus allowing for liquefied gas to flow through the coupling.

[0047] Figure 6 illustrates two magnifications of the coupling part 1 as illustrated in figure 5 in a state wherein the first valve 11 is open and the second valve 12 is open.

[0048] Figure 7 illustrates a coupling comprising a first 1 and second 2 coupling parts. The coupling parts 1 , 2 might have different forms, locking mechanisms, handles, and other features depending of the implementation for the coupling.