Patent Publication Number: US-2023151919-A1

Title: Coupling device and method

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of priority under 35 U.S.C. § 119 (a) and (b) to French Patent Application No. 21120489, filed Nov. 15, 2021, the entire contents of which are incorporated herein by reference. 
     BACKGROUND 
     The invention relates to a coupling device and method. 
     More particularly, the invention relates to a detachable coupling device with automatic closure for the transport of cryogenic fluid, comprising two fluid transport pipes extending in a longitudinal direction and each comprising, at one connection end, a valve mechanism configured to automatically dose the pipe when the connection ends are separated and to enable the pipe to be opened when the connection ends are coupled, the device moreover comprising an external tube disposed around each transport pipe and defining a space under vacuum for the thermal insulation of the transport pipe, in the coupled position the two connection ends are configured to be relatively longitudinally displaceable between a first, dosed configuration, in which the valve mechanisms are dosed and prevent fluidic communication between the two transport pipes, and a second, open configuration, in which the valve mechanisms are open and ensure fluidic communication between the two transport pipes. 
     The coupling devices for the transfer of cryogenic fluids (for example liquefied hydrogen) make use of a “Johnston” type fitting. The known devices require the line to be purged before and after coupling. 
     Other connection types exist for liquefied natural gas applications. However, the latter are not suitable for hydrogen for effectiveness and safety reasons. In particular, they do not offer the thermal insulation required. 
     One problem of the coupling devices for the transfer of liquid hydrogen is the risk of trapping air inside a dead volume internal to the fitting. This causes the risk of transporting solid air (oxygen) towards tanks or other components. 
     SUMMARY 
     An object of the present invention is to overcome all or some of the drawbacks of the prior art noted above. 
     To that end, the coupling device according to the invention, moreover in accordance with the generic definition it is given in the preamble above, is essentially characterized in that the transition from the first, closed configuration to the second, open configuration is realized by a relative longitudinal movement of the two fluid transport pipes close to one another and/or by a relatively movement of the two valve mechanisms close to one another, wherein the connection end of a first one of the two pipes comprises a sealing ring secured to the external tube, the sealing ring comprising a set of seal(s) that is (are) configured to ensure sealing with respect to the outside between the two connection ends when the two connection ends are coupled, the sealing ring being movable in translation in the longitudinal direction relative to the external tube between two distinct positions during the transition from the first, dosed configuration to the second, open configuration. 
     Furthermore, embodiments of the invention may have one or more of the following features:
         the device comprises a return member, for example a spring, which urges the sealing ring towards its first position,   the sealing ring comprises an internal face provided with at least one seal which sealingly interacts with the tube to which the sealing ring is secured,   the at least one seal located on the internal face of the sealing ring ensures sealing by being compressed in a plane which is not parallel to the longitudinal direction and/or compressed in a plane which is parallel to the longitudinal direction,   the sealing ring comprises an end face provided with at least one seal which is intended to sealingly interact with the other connection end when the two connection ends are coupled,   the at least one seal located on the end face ensures sealing by being compressed in a plane which is not parallel to the longitudinal direction,   one of the connection ends comprises a movable locking member displaceable between a locking position, in which it is ensured that the two coupled connection ends are secured to one another, and an unlocking position, in which it is not ensured that the two coupled connection ends are secured to one another,   in its locking position, the locking member ensures that the sealing ring borne by a first connection end is secured to the other connection end,   in the first, closed configuration, the valve mechanisms are in contact or are not in contact, and, in the second, open configuration, the valve mechanisms are in contact and exert a thrust force towards one another that ensures the displacement and opening thereof,   the valve mechanism of a first one of the transport pipes comprises a movable valve urged by a return member towards a closed position against a fixed seat disposed around the valve,   the valve mechanism of the second transport pipe comprises a reference valve and a movable seat disposed around the reference valve, the movable seat being urged towards a closed position against the reference valve by a return member,   in the first, closed configuration, the reference valve of the second transport pipe does not push the movable valve of the first transport pipe out of its seat, keeping the valve mechanism closed, the movable seat being in its closed position against the reference valve, and, in the second, open configuration, the connection ends are in contact and the reference valve of the second transport pipe pushes the movable valve of the first transport pipe out of its seat and causes the valve mechanism to open,   the valve mechanism of one of the two transport pipes is housed inside its external tube to a relatively more recessed extent than the other valve mechanism is in its tube, so as to form a male and female type system in which, in the joined position of the two transport pipes, one connection end enters the other connection end,   the space under vacuum between the external tube and the transport pipe comprises a thermal insulator, for example of multilayer type “MLI”,   the reference valve of the second transport pipe is fixed and non-displaceable with respect to its transport pipe,   the valve mechanism of the second transport pipe is located flush with the end face of this second transport pipe,   the method for separating two coupled transport pipes comprises a step of closing the two valve mechanisms via a relative movement of the two fluid transport pipes away from one another and/or a relative displacement of at least part of the two valve mechanisms with retention of the sealed coupling of the two connection ends, and then a step of separating the two connection ends,   during the transition from the step of closing the two valve mechanisms to the separation step, the device passes through the first, closed configuration, in which the two connection ends remain coupled in a sealed manner with respect to the outside and the two valve mechanisms are in the closed position, the step of closing the two valve mechanisms being performed via a relative movement of the two fluid transport pipes away from one another and/or a relative displacement of at least part of the two valve mechanisms.   in the coupled position, the displacement between the first, closed configuration and the second, open configuration is performed manually and/or in a manner controlled by a control member,   the movable locking member comprises a locking ring mounted so as to be movable in translation in the longitudinal direction on one connection end.       

     The invention also relates to a method for coupling two transport pipes of a device according to any one of the features above or below, comprising a step of moving the two connection ends close to one another, in which the two connection ends are coupled in a sealed manner with respect to the outside, a step of placing the two valve mechanisms in contact, a step of opening two valve mechanisms, and a step of causing cryogenic fluid to flow from one pipe to the other. 
     According to a possible particular feature, before the step of opening the two valve mechanisms, the method has an intermediate configuration in which the two connection ends are coupled in a sealed manner with respect to the outside and the two valve mechanisms are in the closed position, the step of opening the two valve mechanisms being performed via an additional relative movement of the two fluid transport pipes close to one another and/or a relative displacement of at least part of the two valve mechanisms. 
     The invention may also relate to any alternative device or method comprising any combination of the features above or below within the scope of the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further particular features and advantages will become apparent on reading the description below, which is given with reference to the figures, in which: 
         FIG.  1    shows a schematic and partial view in longitudinal section, illustrating an exemplary embodiment of a coupling device in a first, separated state, 
         FIG.  2    shows a schematic and partial view in longitudinal section, illustrating the same coupling device in a second, coupled and sealed state in which it is not locked and the valves are closed (first, closed configuration), 
         FIG.  3    shows a schematic and partial view in longitudinal section, illustrating the same coupling device in a third, coupled and sealed state in which it is locked and the valves are closed (first, closed configuration), 
         FIG.  4    shows a schematic and partial view in longitudinal section, illustrating the same coupling device in a fourth, coupled and sealed state in which it is locked and the valves are open (second, open configuration), 
         FIG.  5    shows a schematic and partial view in longitudinal section, illustrating another variant embodiment of the coupling device in a coupled and sealed state in which the valves are closed (first, closed configuration), 
         FIG.  6    shows a schematic and partial view in longitudinal section, illustrating yet another variant embodiment of the coupling device in a coupled and sealed state in which the valves are open (second, open configuration). 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     The coupling device  1  illustrated in  FIG.  1    may be a “quick-action”-type detachable fitting with automatic closure for the transport of cryogenic fluid. This device  1  forms for example a fluidic connection between a (movable or fixed) distributor and a (respectively fixed or movable) receiver, for example for transferring or filling fluid from a source into a receiver, such as a tank. 
     The device comprises two fluid transport pipes  2 ,  3  extending in a longitudinal direction. At one connection end, each pipe  2 ,  3  comprises a valve mechanism configured to automatically close the pipe  2 ,  3  when the connection ends are separated (cf.  FIG.  1   ) and to enable the pipe  2 ,  3  to be opened when the connection ends are coupled (cf.  FIG.  4    or  FIG.  6   ). 
     The device  1  moreover comprises an external tube  10 ,  11  disposed around each transport pipe  2 ,  3 . The external tube  10 ,  11  defines a space under vacuum for thermal insulation around the transport pipe  2 ,  3 . 
     The space under vacuum between the external tube  10 ,  11  and the transport pipe  2 ,  3  comprises for example a thermal insulator, for example of multilayer type “MLI”. 
     In the coupled (sealed) position, the two connection ends are configured to be relatively longitudinally displaced between a first, closed configuration, in which the valve mechanisms are closed and prevent fluidic communication between the two transport pipes  2 ,  3  (cf.  FIG.  2    or  FIG.  3   ), and a second, open configuration, in which the valve mechanisms are open and ensure fluidic communication between the two transport pipes  2 ,  3  (cf.  FIG.  4   ). 
     The transition from the first, closed configuration to the second, open configuration is realized by an additional relative longitudinal movement of the two fluid transport pipes  2 ,  3  close to one another and/or by a relative movement of the two valve mechanisms  4 ,  6 ,  8 ,  5 ,  7 ,  9  close to one another. 
     As illustrated, the valve mechanism  4 ,  6 ,  8  of one  2  of the two transport pipes is preferably housed inside its external tube  10  to a relatively more recessed extent than the other valve mechanism  5 ,  7 ,  9  is in its tube  11 , so as to form a male and female type system in which, in the joined/coupled position of the two transport pipes  2 ,  3 , one connection end enters the other connection end. 
     As illustrated, the connection end of a first one  3  of the two pipes comprises a sealing ring  12  secured to the external tube  11 . 
     The sealing ring  12  comprises a set of seal(s)  14 ,  15  which is (are) configured to ensure sealing with respect to the outside between the two connection ends when the two connection ends are coupled. This sealing ring  12  is for example mounted so as to be movable in translation in the longitudinal direction relative to the external tube  11  between two distinct positions during the transition from the first, closed configuration to the second, open configuration. 
     The device preferably comprises a return member  13 , for example a spring, in particular a compression spring, which urges the sealing ring  12  towards its first position. 
     The sealing ring  12  comprises an internal face provided with at least one seal  15  (and preferably at least two seals  15 ) which sealingly interacts with the tube  11  to which the sealing ring  12  is secured. 
     The sealing ring  12  moreover comprises an end face intended to bear against the other connection end in the coupled position. This end face is provided with at least one seal  14  which is intended to sealingly interact with the other connection end when the two connection ends are coupled (cf.  FIG.  2   ). 
     The sealing ring  12  thus realizes (or contributes to) the sealed link between the two coupled connection ends (with the seals  14 ,  15 ). 
     As illustrated, the at least one seal  15  located on the internal face of the sealing ring  12  can ensure sealing by being compressed in a plane which is parallel to the longitudinal direction. Similarly, the at least one seal  14  located on the end face can ensure sealing by being compressed in a plane which is not parallel to the longitudinal direction, in particular in a plane perpendicular to the longitudinal direction of the pipe. 
     Of course, this arrangement is not limiting; any other arrangement type of axial or radial seal(s) may be envisaged (cf.  FIG.  5   , which will be described below). 
     Radial seals seal the coupling before the valve mechanisms come into contact (without being open). This can trap a non-zero dead volume. However, these radial seals make it possible to displace one part with respect to the other, The axial seal(s) seal the coupling but do not make it possible to axially displace one part with respect to the other. However, this seal configuration is advantageous for minimizing the dead/trapped volumes during the coupling. 
     As illustrated, one of the connection ends may comprise a movable locking member  16  configured to lock and secure the sealed coupling. The locking member  16  is displaceable between a locking position, in which it is ensured that the two coupled connection ends are secured to one another (cf.  FIG.  3    or  FIG.  4   ), and an unlocking position, in which it is not ensured that the two coupled connection ends are secured to one another (cf.  FIG.  2    for example). 
     As illustrated, in its locking position, the locking member  16  can ensure for example that the sealing ring  12  borne by a first connection end is mechanically secured to the other connection end. 
     This locking preferably does not enable any displacement of the two ends. 
     This mechanical locking  16  may be necessary to lock the sealing ring  12 , in particular when the opening of the valves has ended. This is because, in this configuration, without this locking, the pressure force of the fluid in the device can be greater than the load of the spring  13  that pushes the sealing ring against the other connection end. 
     The locking member  16  may be mounted on one of the two connection ends. 
     In the exemplary embodiment of  FIG.  2   , in the first, closed position (sealed coupling and closed valves), the valve mechanisms are in contact (or flush with one another). Of course, as a variant, in this first, closed configuration the valve mechanisms might not be in contact (or even might be remote from one another). 
     The valve mechanism  5 ,  7 ,  9  of a first one of the transport pipes  3  may comprise a movable valve  5  urged by a return member  9  (spring for example) towards a closed position against a fixed seat  7  disposed around the valve  5 . 
     The valve mechanism of the second pipe may be of the same type. However, as illustrated, the valve mechanism  4 ,  6 ,  8  of the second transport pipe  2  may comprise a fixed reference valve  4  and a movable seat  6  disposed around the reference valve  4 . The movable seat  6  is urged towards a closed position against the reference valve  4  by a return member  8 , for example a spring. 
     As illustrated in  FIG.  2    and  FIG.  3   , in the first, closed configuration, the reference valve  4  of the second transport pipe  3  does not push the movable valve  5  of the first transport pipe  2  out of its seat  7 . This keeps the valve mechanism closed and prevents the flow of fluid. The movable seat  6 , for its part, is in its closed position against the reference valve  4 . 
     By contrast, in the second, open configuration (cf.  FIG.  4   ), the connection ends are in contact and the reference valve  4  of the second transport pipe  3  pushes the movable valve  5  of the first transport pipe  2  out of its seat  7  and causes the valve mechanism to open. Similarly, the valve mechanism  4 ,  6 ,  8  of the second pipe  2  is open. For example, the movable seat  6  is separated from the reference valve  4  counter to the pressure of the spring  8 . 
     The relative movement-away from the second, open configuration to the first, closed configuration causes the valve mechanisms to automatically close (in particular via the return members). 
     Thus, the sealing ring  12  makes it possible to relatively displace the two coupled connection ends with retention of the sealing between them. 
     Because of its mobility relative to its connection end, the ring may thus form an end of one connection end that is retractable with respect to the other, retaining the sealing between the two connection ends during their relative movement in the longitudinal direction. 
     The coupling may comprise the following steps:
         separated state, valve mechanisms closed cf.  FIG.  1   ,   coupled, sealed and non-locked state, valve mechanisms still closed cf. Fig,  2 ,   coupled, sealed and locked state, valve mechanisms still closed cf.  FIG.  3   ,   coupled, sealed and locked state, valve mechanisms open cf.  FIG.  4   .       

     In a positionally possible alternative, the sequence of use might be as follows:
         inserting the movable connection end into or around the fixed connection end (the sealing is not yet realized, the valves are closed),   locking the link, for example by locking the sealing ring  12  (the sealing between the connection ends is realized, the valves are closed),   displacement of the movable part towards the fixed part to open the valves.       

     This relative displacement of the connection ends to open the valves (and the reverse movement) can be implemented by a quick-action connection mechanism of any kind, comprising mating attachment members on the two connection ends, for example a mechanism of bayonet type, lever type, ram type, or another type. 
     In this non-limiting example, the sealing ring  12  is secured to the (fixed or movable) male connection end, but could be borne by the other (female and movable or fixed) connection end. 
     This sealing ring  12  is preferably mounted on the outer part, which is relatively hot, of the coupling device (as opposed to the cryogenic part close to the valve mechanisms in contact with the cryogenic fluid). 
     The sealing ring  12  is preferably mounted on the male-type and movable connection end of the device  1  (this limits the dead volumes in the coupling). However, any other configuration is conceivable. 
     The variant of  FIG.  6    corresponds to the state of  FIG.  4    (sealed coupling and closed valve mechanisms) and illustrates examples of valve mechanisms in the open position. The same elements are denoted by the same reference numerals. In addition, for the sake of simplification, this illustrated variant does not have a locking ring (optional). 
     The variant of  FIG.  5    corresponds to the state of  FIG.  2    (sealed coupling and closed valve mechanisms). In this variant, a seal  14  of the end face ensures radial sealing (compression in a plane parallel to the longitudinal direction). In addition, at the internal seal  15  there is axial sealing (compression in a plane perpendicular to the longitudinal direction). 
     Depending on the balance of forces and in particular the calibration of the return member  13  that urges the sealing ring  12 , the locking member described above may possibly be left out. 
     The locking and actuation of the valve mechanisms can be done directly between the fixed connection end and the movable connection end without entailing the sealing ring  12 . In this case, to obtain the sealing, in particular via an axial seal, this seal may be pressed (for example by a spring or by pressure). 
     One advantageous solution is to provide a radial-type seal on the female part and an axial seal on the male part. This makes it possible to press the axial seal  15  by virtue of the pressure exerted by the fluid in the device. 
     The invention thus proposes a rapid, simple and safe device  1  for repeatably connecting and disconnecting pipes and/or tanks for cryogenic fluids, such as liquid hydrogen. The connection ends can easily be handled manually. 
     The device minimizes the entry of heat into the cold part. The outer part is not at cryogenic temperature. 
     The connection/disconnection can be performed in successive steps: i) coupling and locking, if appropriate (heat-tightness) ii) opening the valve mechanisms (fluid transfer) via an additional movement, towards or away, permitted by the sealing ring  12  iii) closing the valve mechanisms (cryogenic sealing) iv) unlocking and separation. 
     In addition, the device may incorporate an emergency separation system (“breakaway”). 
     It will be understood that many additional changes in the details, materials, steps and arrangement of parts, which have been herein described in order to explain the nature of the invention, may be made by those skilled in the art within the principle and scope of the invention as expressed in the appended claims. Thus, the present invention is not intended to be limited to the specific embodiments in the examples given above.