Patent Publication Number: US-7909365-B2

Title: Fluid system coupling with handle actuating member

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part and claims the benefit of U.S. patent application Ser. No. 11/465,570, filed on Aug. 18, 2006, now abandoned, entitled FLUID SYSTEM COUPLING WITH PIN LOCK, which is a continuation-in-part and claims the benefit of U.S. patent application Ser. No. 10/164,945, filed on Jun. 7, 2002, now U.S. Pat. No. 7,152,630, entitled FLUID SYSTEM COUPLING, which is a continuation-in-part and claims the benefit of U.S. patent application Ser. No. 09/628,075, filed on Jul. 28, 2000, now U.S. Pat. No. 6,672,327, entitled DRY BREAK VALVE ASSEMBLY, all of which are incorporated herein in their entireties by this reference. 
    
    
     BACKGROUND 
     1. Technological Field 
     The present invention relates generally to fluid system components. More particularly, embodiments of the present invention relate to coupling elements for fluid system components, in which the coupling elements facilitate quick and efficient coupling/decoupling of the fluid system components. Further, embodiments of the present by invention relate to fluid system components which substantially prevent unintentional removal of a coupling element until the fluid system line pressure, or relative pressure differential, is reduced to a safe level. 
     2. Related Technology 
     In recent years, environmental concerns have been receiving significantly more attention, and various governmental agencies have responded by implementing stringent regulations to reduce or prevent pollution. Many of these regulations and concerns are directed towards those industries that transport fluids. For example, it is very difficult to transport a fluid without spilling or leaking some of the fluid into the environment. Thus, some environmental regulations require that only minimal leakage occur during handling, processing, or transportation of the fluid. 
     These environmental concerns become especially clear when considering the magnitude of the industries that handle hazardous fluids that, if allowed to escape even in relatively small quantities, can cause significant damage. There is a concern, therefore, to protect both the public and the environment from these types of fluids. While some fluids that are transported, such as water and milk, may not significantly pollute the environment when they are leaked or spilled, the loss of fluid into the environment is nevertheless viewed as a general waste of resources. More generally, the loss of fluid into the environment is not desirable even if the fluid does not contribute to pollution. 
     Within the transportation industry, a variety of different devices are used to transport a fluid from a source to a destination. These devices often use valve assemblies and conduits of various types to both connect the source to the destination as well as to manage fluid flow through the conduit. Typically, the conduit is pressurized to direct fluid toward the desired destination. With each transfer of fluid, there is a risk that leakage will occur due to human error, equipment malfunctions, or the like. 
     A common source of fluid leaks and fluid spills are the valves and other components and devices employed in fluid systems. By way of example, some valves may have leaks that permit flow through the valve even when the valve is secured in the closed position. In other instances, one or more joints defined by constituent elements of the valve, such as in the case of valves designed to be taken down in two or more pieces, and/or one or more joints at least partially defined by the valve, such as a valve-to-flange connection, may be defective, resulting in leakage of some or all of the system fluid. Unfortunately, problems such as these often do not manifest themselves until after flow has been established through the valve, component, or device. 
     Thus, in many instances, the system operator is limited in terms of the affirmative steps that can be taken to prevent a spill that may result from one or more defective joints, and oftentimes can only correct the spill when it occurs. This is true in the case of joints that are defectively assembled, or are otherwise defective upon assembly, as well as in the case of joints that become defective over a period of time due to operating, or other, conditions. 
     Other problems exist as well. For example, various types of valves have been designed to stop, or “check,” fluid flow through the valve when the valve is taken down into two or more constituent parts or assemblies. One known device for checking fluid flow is a ball check valve. A ball check valve is essentially a ball which rests against a ball seat to form a valve. An operator may use the ball check valve to initiate or terminate the fluid flow. Despite the check feature of the ball check valve, a problem exists in the integrity of the fluid transfer system when the valve or conduit undergoes stress. 
     When the conduit and the valve are subjected to forces such as stretching, pulling, twisting, and the like, the fluid being transferred through the conduit and the valve may leak or spill into the environment. More particularly, the conduit, rather than the ball check valve, is likely to rupture or otherwise malfunction in the presence of these forces. Thus, while the ball check valve is appropriate for checking fluid flow, it does not prevent spillage or leakage when subjected to external stress. Because the conduit is likely to rupture, or otherwise malfunction, in these types of situations, the spillage or leakage of fluid into the environment can be significant because the fluid flow can no longer be checked. 
     For example, when a fuel transport vehicle is delivering liquid through a hose into a fuel tank, one end of the hose is attached to the fuel transport vehicle, and the other end of the hose is attached to a fuel tank. A valve such as a ball check valve may be disposed at the vehicle end of the hose such that fluid communication through the hose may be established or checked. 
     In the event the fuel transport vehicle drives away with the hose still connected, the connection will likely break or rupture. Because the hose is typically the weakest part of the connection, the break usually occurs somewhere in the hose and fluid escapes into the environment. In this example, the ball check valve typically does not disassemble because it is much stronger than the hose. Even if the ball check valve were to break instead of the hose, fluid would still leak from the system. Such problems are particularly acute in the context of automated environments and operations where few, or no, humans may be present, and a leak may go unnoticed for a relatively long period of time. 
     Another concern relates to the coupling and uncoupling of caps, valves, and other fluid system components that are employed, for example, in fuel, chemical, sewage, or other fluid transfer or processing systems. In particular, typical quick coupling devices are configured so that an operator can uncouple the mating halves of the quick coupling device, even in the presence of line pressure. Such an arrangement is problematic for a variety of reasons. 
     By way of example, in the event the line wherein the quick coupling device is located is charged with hazardous materials such as chemicals, sewage, fuels, or gases such as chlorine and methane, the operator performing the uncoupling operation could be seriously injured or killed when such materials escape from the line. Moreover, such hazardous materials are pollutants and significant time and cost is often involved in the cleanup of such materials. 
     A related problem with typical quick coupling devices concerns the pressure exerted by the material in the line wherein the quick coupling device is located. In particular, such pressure may cause the halves of the quick coupling device to rapidly come apart in an uncontrolled and dangerous manner, thereby injuring the operator and/or damaging nearby equipment. The forces resulting from such pressure can often be significant, even where the line pressure is relatively low. Thus, in a six inch diameter (nominal) pipe for example, even a relatively low pressure of ten (10) lbs./in. 2  (“psi”) would exert a force of about one thousand (1000) pounds on a pipe cap attached to the end of the pipe. 
     Not only are such pressures dangerous, but operators may not have any way to verify, in advance of performing the uncoupling operation, whether or not the line is pressurized. Further, even if an operator is aware that pressure is present, the operator may, through inattentiveness, negligence, or for other reasons, nevertheless attempt to uncouple the quick coupling device. 
     In view of the foregoing, what is needed is a fluid system component having features directed to addressing the foregoing exemplary considerations, as well as other considerations not disclosed herein. More particularly, an exemplary fluid system component includes features directed to facilitating the secure engagement, and ready disengagement, of the mating halves of the fluid system component, while at the same time preventing intentional or accidental disengagement of the mating halves when a predetermined pressure is present in the line. 
     BRIEF SUMMARY OF EXEMPLARY EMBODIMENTS OF THE INVENTION 
     In general, embodiments of the invention are concerned with a fluid system component that, among other things, facilitates the secure engagement, and ready disengagement, of mating halves of the fluid system component, while at the same time preventing intentional or accidental disengagement of the mating halves when a predetermined pressure is present in the line. 
     In one exemplary embodiment of the invention, a fluid system component is provided that includes mating male and female halves. The male half of the fluid system component includes a wall having an outer surface on which a plurality of grooves are formed. The grooves are generally configured so that each of a plurality of rollers present on the outer surface of a wall of the female half of the fluid system component enters, and travels along, a corresponding groove as the male and female halves are rotatably engaged together. 
     Further, the grooves defined in the male half of the fluid system component are configured to define an angle with respect to the longitudinal axis of the fluid system component, so that the male and female halves advance toward each other as they are rotatably engaged. Each of the grooves also includes a terminal segment that is connected to, but offset from, the intermediate and entry segments of the groove. 
     An exemplary embodiment of the present invention further provides a locking mechanism that substantially prevents takedown of the fluid system component as a result of unintentional or accidental rotation of the fluid system components. The locking mechanism includes a locking pin that extends through the wall of the female half of the fluid system component and into a recess defined in the outer wall of the male half of the fluid system component. The locking pin is movably connected to the female half of the fluid system component and is biased so that a distal end of the locking pin protrudes from the inner wall of the female half of the fluid system component to engage the recess in the male half of the fluid system component. The engagement between the locking pin and the recess in the male half of the fluid system component prevents relative rotation of the male and female halves of the fluid system component and thus takedown of the fluid system component. 
     An exemplary locking mechanism further includes a pin handle at or near the proximate end of the locking pin. The pin handle allows a user to withdraw the distal end of the locking pin from a recess in the male half of the fluid system component. Once the locking pin is disengaged from the recess in the male half of the fluid system component, the male and female halves of the fluid system component can be rotated relative to each other so that they can be disengaged from each other. 
     A coupling handle can also be formed on the outer wall of the female half of the fluid system component. The coupling handle can facilitate movement and manipulation of the fluid system component, such as rotation of the female half relative to the male half of the fluid system component. The coupling handle is, in one example, adjacent to the pin handle, which is on or near the proximate end of the locking pin. Such placement of the coupling handle and the pin handle allows a user to simultaneously hold both handles. While simultaneously holding both handles, a user can withdraw the pin and rotate the female half into engagement with the male half of the fluid system component. Thereafter, the user can release the pin handle to engage the locking pin within the recess defined in the male half without having to let go of the coupling handle with either hand. 
     In operation, the male and female portions are brought together until each roller of the female portion has engaged a corresponding groove of the male portion. The two halves are then rotated in opposite directions, causing the rollers to advance along their corresponding grooves and thereby move the male and female halves toward each other. The two halves continue to rotate until each roller enters the terminal segment of its corresponding groove, at which point engagement is completed. Thus engaged, the male and female halves cooperate to define a fluid passageway. 
     The introduction of a pressurized fluid into the fluid passageway acts on the fluid system component in such a way that a force is exerted that resists movement of the rollers out of the terminal segment and back into the intermediate or entry segments of the groove. Thus, the groove geometry affords the fluid system component the capability to use the line pressure in such a way as to prevent disengagement of the fluid system component halves until the line is suitably depressurized. 
     These and other aspects of embodiments of the present invention will become more fully apparent from the following description and appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more particular description of various aspects of the embodiments of the invention illustrated in the appended drawings will now be rendered. Understanding that such drawings depict only exemplary embodiments of the invention, and are not therefore to be considered limiting of the scope of the invention in any way, various features of such exemplary embodiments will be described and explained with additional specificity and detail through the use of the accompanying drawings in which: 
         FIG. 1  depicts an exemplary operating environment for at least some embodiments of the present invention; 
         FIG. 2  is a perspective view of an embodiment of the dry break valve assembly which includes a source housing and a destination housing that can be releasably connected to each other using a sleeve; 
         FIG. 3  depicts an embodiment of a sleeve which releasably seals and connects a source housing with a destination housing; 
         FIG. 4  is a perspective view indicating various details of a breakable link assembly that is an integral portion of a collar; 
         FIG. 5  is a perspective cutaway view of an embodiment of the present invention, illustrating various features of an actuating mechanism; 
         FIG. 6  is a cross section view of an exemplary sealing interface within an embodiment of a dry break valve assembly; 
         FIG. 7  is a perspective view illustrating various features of an exemplary embodiment of an actuating mechanism disposed within an embodiment of a dry break valve assembly; 
         FIG. 7A  is a side view illustrating various features of an embodiment of an actuating mechanism positioned so as to allow fluid flow through the dry break valve assembly; 
         FIG. 7B  is a side view illustrating various features of an embodiment of an actuating mechanism positioned so as to substantially prevent fluid flow through the dry break valve assembly; 
         FIG. 8  is a perspective view of an alternative embodiment of a dry break valve assembly depicting various features of an exemplary embodiment of a groove arrangement that includes three grooves each of which include a terminal segment; 
         FIG. 8A  is a section view illustrating various aspects of the exemplary embodiment of the grooves depicted in  FIG. 8 ; 
         FIG. 9  is a section view of an exemplary embodiment of a dry break valve assembly that illustrates aspects of the relation between the fluid pressure in the fluid passageway and the engagement of the first and second housing portions; 
         FIG. 10  is a top view of an exemplary embodiment of a fluid system component, specifically, a cap assembly, that includes elements configured to be releasably engaged with each other; 
         FIG. 10A  is a section view taken from the top view of  FIG. 10 ; 
         FIG. 10B  is a side view illustrating aspects of an exemplary groove arrangement for the cap assembly; 
         FIG. 11A  is a top view of the exemplary cap assembly illustrated in  FIGS. 10 through 10B , showing the position of various components prior to engagement of the sleeve and collar; 
         FIG. 11B  is a top view of the exemplary cap assembly illustrated in  FIGS. 10 through 10B , showing the position of various components after engagement of the sleeve and collar; 
         FIG. 11C  is a cross-section of the embodiment shown in  FIGS. 11A-11B . 
         FIG. 12  is a side view illustrating various aspects of an exemplary groove configuration and arrangement that includes multiple overlapping grooves each having a plurality of intermediate segments; 
         FIG. 13  is a bottom view of an exemplary embodiment of a fluid system component, specifically, a cap assembly that includes means for selectively securing elements of the fluid system component in relation to each other; 
         FIG. 13A  is a section view taken from the bottom view of  FIG. 13 ; 
         FIG. 14A  is a perspective view of an alternative embodiment of a fluid system component that includes a pin handle attached to a locking pin for selectively securing the fluid system component to a fluid conduit; 
         FIG. 14B  is a bottom view of the exemplary fluid system component illustrated in  FIG. 14A ; 
         FIG. 14C  is a section view of the fluid system component of  FIGS. 14A and 14B , the fluid system component being mounted to a fluid conduit. 
     
    
    
     DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS OF THE INVENTION 
     Reference will now be made to figures wherein like structures will be provided with like reference designations. It is to be understood that the drawings are diagrammatic and schematic representations of various embodiments of the invention, and are not to be construed as limiting the present invention, nor are the drawings necessarily drawn to scale. 
     With reference first to  FIG. 1 , one embodiment of a fluid transfer system is indicated generally at  100 . Note that, as contemplated herein, “fluid” includes liquids, gases, liquid-gas combinations, slurries, liquid-solid combinations, gas-solid combinations, and liquid-solid-gas combinations. In the exemplary embodiment depicted in  FIG. 1 , fluid transfer system  100  includes a fluid source  102  configured for fluid communication with a dry break valve assembly  200 . Dry break valve assembly  200 , in turn, is configured for selective fluid communication with a fluid destination  104 , by way of a fluid conduit  106 . 
     As discussed elsewhere herein, it will be appreciated that dry break valve assembly  200  may be located, in its entirety, at fluid source  102 , or alternatively at fluid destination  104 . In one embodiment, discussed in detail below, dry break valve assembly  200  comprises at least two discrete portions, one of which may be located at fluid source  102 , and the other of which may be located at fluid conduit  106 , or vice versa in a fluid loading situation. 
     As contemplated herein, the term “conduit” is meant to include any structure or device adapted to facilitate transportation of a fluid, wherein such structures and devices include, but are not limited to, pipes, hoses, tubes, or the like. Fluid conduit  106  may be constructed of a variety of materials, or combinations thereof, including, but not limited to, metal, plastic, rubber, and the like. 
     With continuing reference to  FIG. 1 , the fluid source  102  is illustrated as a fluid transport vehicle, and the fluid destination  104  is illustrated as an underground tank. However it will be appreciated that fluid source  102  and/or fluid destination  104 , may comprise any of a variety of different static or mobile structures and vehicles. Such structures and vehicles include, but are not limited to, air, water, or land vehicles, such as, but not limited to, trucks, boats, automobiles, motorcycles, ships, railcars, aircraft, and the like, as well as structures such as tanks, reservoirs, and the like. 
     In operation, a pressure differential is established between fluid source  102  and fluid destination  104  so as to cause flow of the fluid through fluid conduit  106  in the desired direction. It will be appreciated that the pressure differential may be established in such a way as to cause flow to proceed in the opposite direction as well. The pressure differential may result from the force of gravity, or may alternatively be established by various types of equipment and devices including, but not limited to, pumps and the like. 
     In general, dry break valve assembly  200  facilitates management and control of fluid flow between fluid source  102  and fluid destination  104 . In particular, valve assembly  200  allows for selective establishment and termination of fluid communication between fluid source  102  and fluid destination  104 . Additionally, dry break valve assembly  200  facilitates releasable engagement of two different fluid system components, for example, fluid conduit  106  and fluid source  102 . Finally, dry break valve assembly  200  includes various features which substantially prevent fluid leakage should the discrete portions of dry break valve assembly  200  be separated for any reason. 
     With reference now to  FIG. 2 , dry break valve assembly  200  includes a first housing portion  202  and second housing portion  204 . As used herein, the portion of the valve assembly closest to the fluid source is referred to as the source housing while the other housing portion is referred to as the destination portion. Either portion of the dry break valve assembly can be the source housing or the destination housing. Coupling  500  serves to removably secure first housing portion  202  and second housing portion  204  in a substantially leakproof engagement. 
     Substantially disposed within first housing portion  202  and second housing portion  204 , respectively, are flow control assemblies  300 A and  300 B. In general, flow control assemblies  300 A and  300 B facilitate management of fluid flow through conduits, or the like, connected to first housing portion  202  and second housing portion  204 , respectively. Also disposed within first housing portion  202 , and discussed in greater detail below, is an actuating mechanism (not shown in  FIG. 2 ), which serves to manipulate the position of flow control assemblies  300 A and  300 B in response to input provided by way of actuating lever  402 . Thus, the position of the flow control assemblies  300 A and  300 B may vary between fully open and fully closed. 
     First housing portion  202  includes a conduit connector  202 A. Conduit connector  202 A is configured to attach to fluid conduit  106  (shown in  FIG. 1 ), wherein such attachment may be accomplished in a variety of ways including, but not limited to, welding, brazing, soldering, and the like. Alternatively, conduit connector  202 A may comprise a compression fitting, threaded fitting, or the like for attaching to fluid conduit  106 . 
     In similar fashion, second housing portion  204  has a conduit connector  204 A. Conduit connector  204 A is configured to attach to fluid conduit  106 , wherein such attachment may be accomplished in a variety of ways including, but not limited to, welding, brazing, soldering, and the like. Alternatively, conduit connector  204 A may comprise a compression fitting, threaded fitting, or the like for attaching to fluid conduit  106 . It will be appreciated that conduit connector  202 A and/or conduit connector  204 A may, alternatively, be connected directly to fluid source  102  or fluid destination  106 . 
     Directing attention now to  FIG. 3 , and with continuing attention to  FIG. 2 , additional details regarding coupling  500  are provided. As indicated in  FIG. 3 , coupling  500  includes a first engaging portion  500 A and a second engaging portion  500 B joined together by collar  502  which serves to substantially prevent relative motion between first engaging portion  500 A and a second engaging portion  500 B. Preferably, first engaging portion  500 A and a second engaging portion  500 B each comprise an outward extending annular ridge or the like which, when brought into a confronting relation with each other, are collectively configured to mate with corresponding structure defined by collar  502 , as suggested in  FIG. 3 . It will be appreciated however, that coupling  500  and collar  502 , either individually or collectively, may be configured in any number of alternate ways that would facilitate achievement of the functionality disclosed herein. In addition the connecting portions of the engaging portions  500 A and  500 B may be ridged to ensure that relative motion between the portions does not occur. 
     In one embodiment, first engaging portion  500 A and a second engaging portion  500 B each further includes a plurality of pins  504  that mate with corresponding grooves  202 B and  204 B, defined by first housing portion  202  and second housing portion  204 , respectively. Thus, a rotary motion imparted to coupling  500  by way of handles  506  releasably joins first engaging portion  500 A and a second engaging portion  500 B to first housing portion  202  and second housing portion  204 , respectively, by causing pins  504  to travel to the respective ends of grooves  202 B and  204 B. Preferably, grooves  202 B and  204 B are of such a length that a rotary motion of about 90 degrees is adequate to releasably couple first housing portion  202  to second housing portion  204 . It will be appreciated that a rotary motion of about 120 degrees in the opposite direction will be effective to disengage coupling  500  and thus release first housing portion  202  from second housing portion  204 . 
     It will be appreciated that the arrangement of coupling  500  with respect to first housing portion  202  and second housing portion  204  may be varied in a number of ways. For example, in one embodiment, first engaging portion  500 A is integral with first housing portion  202 , so that only second engaging portion  500 B comprises pins  504 . Correspondingly, only grooves  204 B are present and grooves  202 B are not required. In this embodiment, a rotation, preferably about 120 degrees, imparted to coupling  500  by way of handles  506  causes rotating pins  504 , or bearings in another embodiment, to travel the length of grooves  204 B so that coupling  500  thereby releasably joins first housing portion  202  to second housing portion  204 . 
     Yet another embodiment employs essentially a reverse configuration of that just discussed. In particular, in this embodiment, second engaging portion  500 B is integral with second housing portion  204 , and only first engaging portion  500 A includes pins  504 . Correspondingly, only grooves  202 B are present and grooves  204 B are not required. In this embodiment, a rotation, preferably about 90 degrees, imparted to coupling  500  by way of handles  506  causes pins  504  to travel the length of grooves  202 B so that coupling  500  thereby releasably joins first housing portion  202  to second housing portion  204 . 
     Finally, it will be appreciated that other types of structure and devices may be usefully employed to achieve the functionality collectively provided by pins  504  and grooves  202 B and  204 B. Accordingly, other structures and devices that provide such functionality are contemplated as being within the scope of the present invention, wherein such other structures and devices include, but are not limited to, threaded connections, spring-biased connections, and the like. 
     Directing attention now to  FIG. 4 , and with continuing attention to  FIG. 3 , additional details regarding collar  502  of coupling  500  are provided. In particular, collar  502  further includes a breakable link assembly  600 . Generally, breakable link assembly  600  serves two primary purposes. First, breakable link assembly  600  serves to retain collar  502  securely in place about first engaging portion  500 A and second engaging portion  500 B of collar  502 . Further, breakable link assembly  600  includes a sacrificial element that is designed to break, thereby allowing first engaging portion  500 A and second engaging portion  500 B to separate from each other, when a force, or forces, of predetermined magnitude are applied to particular elements of fluid transfer system  100 , such as to valve assembly  200 , or to fluid conduit  106 . 
     In effect, when the sacrificial element breaks, then the coupling  500  is no longer capable of joining the first and second housings of the valve assembly and the valve assembly disassembles into two separate components. As previously described, fluid flow from each separate housing may be checked and when the valve assembly separates in this manner, fluid flow is checked and fluid spillage or leakage is thereby minimized. 
     As suggested in  FIG. 4 , collar  502  is essentially C-shaped, having an opening between its two ends. Breakable link assembly  600  is disposed across the opening thus defined and includes a threaded member  602 , such as a bolt or the like, defining a bore (not shown) near one end. Preferably, the bore thus defined is substantially perpendicular to the longitudinal axis of threaded member  602 . A shear pin  604  is slideably disposed in the bore and the opposing ends of shear pin  604  are received in collar  502  as indicated. Preferably, shear pin  604  is prevented from exiting the bore by way of cotter pins  606 , or the like, disposed at either end of shear pin  604 . It will be appreciated that shear pin  604  may alternatively be glued, welded, brazed, or otherwise bonded to collar  502  so as to prevent it from exiting the bore in threaded member  602 . 
     Breakable link assembly  600  further includes a nut  608 , or the like, engaged for advancement along threaded member  602 . In operation, nut  608  is rotated so as to advance along threaded member  602  and thus draw the opposing ends of collar  502  securely together. 
     The operation of breakable link assembly  600  proceeds generally as follows. In the event a force, or forces, of predetermined magnitude in either a tensile or axial load are applied to valve assembly  200  and/or to fluid conduit  106 , shear pin  604  will fracture and the valve assembly will disassemble. It will be appreciated that the materials and/or geometry of shear pin  604  may desirably be varied to adjust the point at which fracture will occur. It will further be appreciated that sacrificial elements other than shear pin  604  may usefully be employed. In general, any sacrificial element and/or breakable link assembly that provides the functionality, disclosed herein, of shear pin  604  and/or breakable link assembly  600  is contemplated as being within the scope of the present invention. 
     Upon fracture of shear pin  604 , threaded member separates from collar  502 , thus permitting the ends of collar  502  to move apart and thereby allow separation of first housing portion  202  and second housing portion  204 . The functionality provided by breakable link assembly  600  thus ensures that in the event a predetermined level of force is applied to dry break valve assembly  200 , or to components to which it is connected, dry break valve assembly  200  will break dry, and thus substantially prevent any material leakage of fluid. Further, breakable link assembly  600  substantially ensures that in the event such forces are applied, no material damage occurs to the components of fluid transfer system  100  (see  FIG. 1 ). Thus, in addition to minimizing the fluid loss that would otherwise occur, the conduit  106  is preserved and damage is not done to the fluid source or the fluid destination. 
     Note that a variety of means may be profitably employed to perform the functions enumerated herein of sealingly engaging first housing  204  with second housing  206  using coupler  500 . Coupler  500  is an example of means for sealingly engaging first housing portion  202  and second housing portion  204 . Accordingly, the structure disclosed herein simply represents one embodiment of structure capable of performing this function. It should be understood that this structure is presented solely by way of example and should not be construed as limiting the scope of the present invention in any way. 
     The valve assembly  200  and its various parts may be made of a range of materials depending on the type of fluid being transferred. Preferably, a material is chosen that can withstand corrosion and high temperature thermal cycling, such as carbon steel or stainless steel. Generally, valve assembly  200  may be constructed from Austenitic steel. 
       FIG. 5  shows an exploded perspective view of various features of the flow control assemblies of valve assembly  200 . The following description of the housing configuration and flow control assemblies is by illustration only and not by way of limitation. Generally, flow control assembly  300 A may comprise a flow control member  302 A, a guide  322 A, a resilient member  344 A, a fitting member  348 , and a snap ring  364 A. Similarly, flow control assembly  300 B may comprise a flow control member  302 B, a guide  322 B, a resilient member  344 B, a sealing member  350 , and a snap ring  364 B. 
     Flow control assemblies  300 A and  300 B have a flow control member  302 A and  302 B, respectively. As shown in  FIG. 3 , flow control members  302 A and  302 B have a round disc-like valve gate  304 A and  304 B, respectively. Valve gate  304 A contains a bore  320  substantially in the center of the valve gate so as to allow a substantially cylindrical piece to pass through the bore. It will be understood that bore  320  may be any geometrical shape (e.g., square, rectangular, polygonal, etc.) that will allow passage of a corresponding geometrical-shaped piece to pass through the bore. 
     Attached to valve gate  304 A is a hollow driver shaft  316 . Driver shaft  316  is placed in transverse relation to valve gate  304 B. Preferably, driver shaft  316  is substantially concentric with bore  320  and contains substantially the same geometric shape as bore  320 . Attached to valve gate  304 B is a member  318 , which may be solid or hollow. Driver shaft  316  and member  318  may be attached to valve gate  304 A and  304 B by any means known in the art, such as, but not limited to, welding, adhesive bonding, or may be formed integrally with valve gates  304 A and  304 B. 
       FIG. 5  further illustrates guides  322 A and  322 B. Guides  322 A and  322 B essentially add structural support to flow control assemblies  300 A and  300 B. Guides  322 A and  322 B contain bores  326 A and  326 B whose inner diameters correspond respectively with the outer diameters of driver shaft  316  and member  318 . In practice, driver shaft  316  slideably passes through bore  326 A, and, similarly, member  318  slideably passes through bore  326 B. Preferably, guides  322 A and  322 B are essentially hollow except for three support bars generally designated as  340 A and  340 B. The hollow structure allows for structural members to pass through guides  322 A and  322 B and to be movably connected to valve gates  304 A and  304 B, which will be discussed in further detail later in this specification. However, it will be appreciated that guides  322 A and  322 B may be constructed having a partially solid configuration as long as the requisite area is present to allow for movement of parts. 
       FIG. 5  shows resilient member  344 A and  344 B which are placed onto driver shaft  316  and solid member  318 , respectively. Resilient members  344 A and  344 B are shown in  FIG. 5  to be springs. However, one skilled in the art will understand that resilient members  344 A and  344 B may be any structure which maintains a bias such as, but not limited to, a rubber material, an elastic material, polished metal, and the like. 
       FIG. 5  further depicts fitting member  348  and corresponding sealing member  350 . The configuration of fitting member  348  and sealing member  350  will be discussed in more detail later in this specification. However, in general terms, fitting member  348  is tapered on one side to provide a valve seat for valve gate  302 A. Similarly, sealing member  350  is tapered on one side to provide a valve seat for valve gate  302 B. Preferably, valve gates  302 A and  302 B have corresponding tapers to allow for better sealing engagement. 
     As shown in  FIG. 2 , first housing portion  202  and second housing portion  204  are configured to allow for placement of flow control assemblies  300 A and  300 B to be disposed substantially within each housing.  FIG. 5  shows ridge  360  placed on the interior surface of first housing portion  202 . Ridge  360  acts as structural support for flow control assembly  300 A. During assembly, guide  322 A rests on ridge  360 . Resilient member  344 A is slid onto driver shaft  316 , after which flow control member  302 A is placed into first housing portion  202  with driver shaft  316  passing through bore  326 A. Finally, fitting member  348  is placed into first housing portion  202  to complete the flow control assembly  300 A. It will be understood from the drawings and foregoing discussion that flow control assembly  300 B may be assembled in a manner similar to that for flow control assembly  300 A. 
     It will be noted from  FIG. 5 , that second housing portion  204  has a ledge  362  to provide a similar structural function as ridge  360 . It will be appreciated that first housing portion  202  and second housing portion  204  may have structural ridges and grooves on the interior surface of the housing to provide for better structural engagement of corresponding parts of flow control assemblies  300 A and  300 B. 
     In one embodiment, snap rings  364 A and  364 B are provided for a better sealing engagement when flow control assembly  300 A and  300 B are assembled and for easier disassembly during maintenance of the valve assembly. In another embodiment, valve gate  304 A and  304 B may have an O-ring placed along the taper to provide for better sealing engagement. 
       FIG. 6  is a cross-section of an exemplary embodiment of the dry break valve assembly, illustrating the sealing engagement between first housing portion  202  and second housing portion  204 . First housing portion  202  and second housing portion  204  are joined in sealing engagement preferably in at least two ways—at their outer rims and between fitting member  348  and sealing member  350 . 
       FIG. 6  shows the outer rims of first housing portion  202  and second housing portion  204  in sealing engagement. During assembly of dry break valve assembly  200 , coupler  500  acts to join the outer rims of first housing portion  202  and second housing portion  204  to join them in sealing engagement. Tightening of the coupler  500  further acts to seal valve assembly  200 . Preferably, L-shaped grooves  204 B are configured such that sealing engagement occurs when pins  504  are engaged with L-shaped grooves  204 B. 
     Preferably, a sealing feature is also provided between fitting member  348  and sealing member  350 . As shown in  FIG. 6 , fitting member  348  is provided with a tapered ridge  368  running circumferentially around fitting member  348 . Similarly, sealing member  350  is provided with a corresponding tapered channel  370  running circumferentially around sealing member  350 . The terms “peripheral” and “circumferential” are adopted herewith to describe tapered ridge  368  and tapered channel  370  since tapered ridge  368  is disposed around the perimeter of an interior cavity formed within fitting member  348 . Thus, peripheral tapered ridge  368  peripherally defines the opening of a cavity formed through fitting member  350 . By providing ridge  368  and channel  370  with tapered surfaces, greater surface area is provided which allows an improved sealing engagement without increasing the diameter of the embodiment as is required, for example, to increase the sealing surface area when using a common flange joint. 
     Coupler  500  is provided with compressing edge  372  which biases compensating washer(s)  374  against abutting edge  376  of fitting member  348 . Coupler  500  attaches to the external surface of sealing member  350  by the twist coupling method discussed previously and described in more detail hereinafter. Compensating washer(s)  374 , shown best in  FIG. 6 , serves a dual purpose. Compensating washer(s)  374  provides compensation due to “creeping” (degradation of the seal due to thermal contraction) which occurs at low temperatures. Compensating washer(s)  374  also serves to bias coupler  500  in a direction which will hold pins  504  in the L-shaped grooves  204 B and thus provides the tension necessary for proper operation of the twist coupling. In this regard, when pins  504  are seated in the L-shaped grooves  204 B, compensating washer(s)  374  biases fitting member  348  towards sealing member  350 , and thus assists in forming a proper seal. 
     As can be seen best in  FIG. 6 , fitting member  348  is provided with an abutting edge  376  while coupler  500  is provided with a compressing edge  372 . One pin  504  and L-shaped groove  204 B can be seen in the lower portion of  FIG. 6 . Compensating washer(s)  374  is positioned so that compressing edge  372  and abutting edge  376  are urged apart. Pins  504 , grooves  204 B, and compensating washer(s)  374 , are arranged such that sealing contact between tapered ridge  368  and tapered channel  370  occurs when pins  504  are situated in grooves  204 B. This arrangement provides that when pins  504  are received in the grooves  204 B, compensating washer(s)  374  is partially or fully compressed. 
     It should be understood that compensating washer(s)  374  may be replaced by structures other than that shown and described in connection with  FIG. 6  above. For example, if the embodiment is to be used only under moderate temperature and pressure conditions, compensating washer(s)  374  may be a washer of a resilient or elastic material, such as rubber. Depending upon the application, those skilled in the art will be able to determine what alternative structures and materials may be used for compensating washer(s)  374 . The washer(s)  374  is preferably compressible so as to allow pins  504  to seat in grooves  204 B while urging tapered ridge  368  into sealing engagement with tapered channel  370 . This arrangement provides a coupling which is highly resistant to loosening due to vibration. 
     By the above-described arrangement, tapered ridge  368  is held in tight sealing arrangement with tapered channel  370 . Note that a variety of means may be profitably employed to perform the functions enumerated herein, of providing a sealing engagement between first housing portion  202  and second housing portion  204 . Fitting member  348  and sealing member  350  are examples of means for sealingly engaging first housing portion  202  and second housing portion  204 . Accordingly, the structure disclosed herein simply represents one embodiment of structure capable of performing these functions. It should be understood that this structure is presented solely by way of example and should not be construed as limiting the scope of the present invention in any way. 
     In one embodiment, an actuating mechanism is used to operate the flow control assemblies  300 A and  300 B.  FIG. 7  illustrates a perspective view of an actuating mechanism  501 . Preferably, actuating mechanism  501  uses cam action in operation. Cam action refers generally to a sliding piece in a mechanical linkage used especially in transforming rotary motion into linear motion or vice versa. 
     As depicted in  FIG. 7 , actuating mechanism  501  has a cam handle  503 . Cam handle  503  provides three attachment sites,  512 ,  516 A, and  516 B. Attached to site  512  is cam arm  518 , which in turn is connected to driver  505  at attachment site  514 . Driver  505  has a first end  526  and a second end  528 . Driver  505  is shown in  FIG. 7  to be essentially cylindrical in shape. However, it will be understood that driver  505  may be any geometric shape which will correspond with driver shaft  316  and guide bore  326 A. Driver  505  is essentially a mechanical piece for imparting motion to components of the dry break valve assembly as will be discussed in further detail later in the specification. Attached to sites  516 A and  516 B are displacement shafts  506 A and  506 B. Displacement shafts  506 A and  506 B are shown in  FIG. 7  to be essentially rectangular in shape. However, it will be understood that displacement shafts  506 A and  506 B may be manufactured in any geometric shape, such as cylindrical, elliptical, square, and the like, without departing from the scope of the present invention. 
     Preferably the connections of driver  505  and displacement shafts  506 A and  506 B to cam handle  503  at sites  512 ,  516 A and  516 B are pin connections such that the parts may be movably connected. However, it will be understood that such connections may be done in a variety of ways known to the art including, but not limited to a bolt, a screw, pins, and the like. 
     As shown in  FIG. 2 , cam handle  402 , also referred to as an actuating lever, is connected to an actuating arm  510 , which, in turn, is connected to an actuating lever  508 . Actuating arm  510  is substantially disposed within first housing portion  202 . Actuating arm  510  is preferably placed such that it is substantially over the center of actuating mechanism  501 . Preferably actuating arm  510  and cam handle  503  are connected such that cam handle  503  cannot move independently of actuating arm  510 . 
       FIG. 7  also shows valve gates  304 A and  304 B in relation to actuating mechanism  501 . Valve gate  304 A is shown operably connected to actuating mechanism  501  while valve gate  304 B is disposed in operative relation to the actuating mechanism. Actuating mechanism  501  effects motion in both valve gate  304 A and  304 B at substantially the same time. 
     Valve gate  304 A is shown with second end  528  of driver  505  disposed through bore  320 . Preferably, in the resting position, second end  528  is substantially disposed within bore  320 . However, it will be understood that second end  528  may be partly out of bore  320  without departing from the scope of the present invention. The driver  505  is sized to slidably pass through bore  320  without substantial obstruction from bore  320 . 
     Displacement shafts  506 A and  506 B are shown to be connected to valve gate  304 A at attachment sites  520 A and  520 B. Bore  320  and sites  520 A and  520 B are placed in a triangular configuration with sites  520 A and  520 B being placed substantially equidistant from bore  320 . Sites  520 A and  520 B are also placed substantially equidistant from actuating arm  510  such that displacement shafts  506 A and  506 B are in substantial alignment with one another. Preferably the connections between displacement shafts  506 A and  506 B and connection sites  520 A and  520 B are pin connections such that the parts may be movably connected. However, it will be understood that the parts may be connected by known means in the art, such as, but not limited to, welding, bolting, and the like, without exceeding from scope of the present invention. 
     Referring now to  FIGS. 7A and 7B , the operation of actuating mechanism  501  will be discussed in detail.  FIG. 7A  shows a side view of actuating mechanism  501  at rest. Attachment site  512 , cam arm  518 , and attachment site  514  create a joint  530 . Generally, actuating mechanism  501  operates as follows: the operator depresses the actuating lever  402  (shown in  FIG. 2 ) and then the operator rotates actuating lever  402  which transmits a torque force (TF) through actuating arm  510  (not shown). The torque force (TF) is shown in  FIG. 7B  in the direction of the arrows. Such torque force (TF) rotates cam handle  503  which in turn rotates sites  512 ,  516 A, and  516 B (not shown). Thus, driver  505 , and displacement shafts  506 A and  506 B (not shown) will be in motion at substantially the same time. 
     As cam handle  503  rotates, site  512  rotates in a downward direction forcing motion through cam arm  518  and, in turn, forcing driver  505  in a downward direction. Driver  505  passes through bore  320  such that second end  528  of the driver comes into contact with valve gate  304 B. The downward motion of driver  505  pushes against valve gate  304 B, which displaces valve gate  304 B. The displacement of valve gate  304 B forces resilient member  344 B in a biased position. In one embodiment, located substantially at the center of valve gate  304 B is a groove  524 . The shape of groove  524  corresponds with the geometric shape of the end face of driver  505  such that driver  505  engages groove  524 . 
     At substantially the same time as site  512  is in motion, sites  516 A and  516 B are it rotating in an upward direction, thus pulling displacement shafts  506 A and  506 B in an upward direction. This upward motion pulls at attachment sites  520 A and  520 B (not shown), which in turn pulls valve gate  304 A upward, displacing valve gate  304 A. The displacement of valve gate  304 A forces resilient member  344 A in a biased position. Thus, at substantially the same time, valve gates  304 A and  304 B are displaced or opened to establish fluid communication between the valve gates.  FIG. 7B  shows a side view of the actuating mechanism in full operation (i.e., fully opened) with valve gates  304 A and  304 B being displaced or opened. Thus, at least indirectly, actuating mechanism  501  acts to open both valve gates  304 A and  304 B at substantially the same time. 
     When actuating mechanism  501  is in fully open, with valve assembly  200  completely assembled, actuating mechanism  501  will lock into place automatically. This automatic locking feature is provided by the equilibrium of forces provided by the torque force (TF) and an equal and opposite retention force (RF) created by resilient member  344 B. During actuation, cam arm  518  acts to shift attachment site  512  from attachment site  514 , such that the sites are offset from one another as shown in  FIG. 7B . 
     In other words, when actuating mechanism  501  is completely actuated, joint  530  is in an overextended position. When actuating mechanism  501  is fully actuated, resilient member  344 B is depressed in a biased position. The retention force (RF) created by biased resilient member  344 B acts upwardly through valve gate  304 B to driver  505  to keep joint  530  locked in an overextended position. Once the retention force (RF) is applied, the torque force (TF) is no longer required and actuating mechanism  501  will remain locked until the retention force (RF) is removed. Thus, the present invention provides for an automatic locking mechanism when the actuating mechanism  501  is fully opened and dry break valve assembly  200  is fully assembled. 
     In one embodiment, dry break valve assembly  200  has an automatic check valve feature (i.e., fail closed feature). When the sealing engagement between first housing portion  202  and second housing portion  204  is broken, valve assembly  200  automatically closes to prevent substantial leakage of fluid. As discussed above, valve gates  304 A and  304 B are maintained in the open position by applying a torque force (TF) and/or a retention force (RF). When actuating mechanism  501  is fully activated, and the torque force (TF) is removed, actuating mechanism  501  remains locked due to the retention force (RF) as discussed above. Releasing the retention force (RF) will cause actuating mechanism  501  to automatically close. Essentially, if no torque force (TF) or retention force (RF) is applied, actuating mechanism  501  is predisposed to spring back into its original position because resilient members  344 A and  344 B are biased in the closed position, i.e., valve gates  304 A and  304 B close at substantially the same time. Release of the retention force (RF) may occur when first housing portion  202  is separated from sealing engagement with second housing portion  204 . It will be understood that separation of first housing portion  202  from second housing portion  204  may occur manually or automatically. Thus, the present invention provides for automatic checking of fluid flow whenever the valve assembly is disassembled, whether automatically or manually. 
     While, in the case of some embodiments disclosed herein, it is useful to provide a fluid system component, such as a dry break valve assembly, having mating halves, or portions, that can be readily engaged and disengaged under a variety of pressure conditions, it is useful in other situations to be able to prevent disengagement of the mating portions of the dry break valve when the pressure in the line wherein the dry break valve is employed has exceeded, or dropped below, as applicable, a predetermined level. With the foregoing in view, attention is directed now to  FIG. 8  wherein various details are provided regarding aspects of an alternative embodiment of the dry break valve assembly, generally denoted as  700 . As the operational and structural aspects of the illustrated embodiment are similar in many regards to those of other embodiments disclosed herein, the following discussion will focus primarily on selected aspects of the illustrated embodiment. 
     In particular, the dry break valve assembly  700  includes a first housing portion  702  and second housing portion  704  removably joined together by a coupling  800 . While, in the illustrated embodiment, coupling  800  is integral with first housing portion  702 , coupling  800  comprises a component discrete from both first housing portion  702  and second housing portion  704  in some alternative embodiments. Note that, as discussed elsewhere herein, the use of coupling  800  is not limited to dry break valve assembly  700   
     With continuing reference to aspects of the first and second housing portions, the first housing portion  702  and second housing portion  704  each include a corresponding conduit connector  702 A and  704 A, respectively, configured to attach to a fluid conduit  106  ( FIG. 1 ) or other fluid system component, wherein such attachment may be accomplished in a variety of ways including, but not limited to, welding, brazing and soldering. Other exemplary types of conduit connectors  702 A and  704 A that may be employed include compression fittings and threaded fittings. 
     As indicated in the exemplary embodiment illustrated in  FIG. 8 , the first housing portion  702  and second housing portion  704  each further include a corresponding flow control assembly  900 A and  900 B, respectively, that are operated by way of an actuating mechanism (see, e.g.,  FIG. 7 ) and associated actuating lever  706 , as described elsewhere herein. As discussed in further detail below, rotary motion for engaging and disengaging first housing portion  702  and second housing portion  704  is imparted by way of handles  802  joined to coupling  800 . 
     In general, the engagement of first housing portion  702  and second housing portion  704  is achieved by way of mating pins and grooves, aspects of which are illustrated in  FIG. 8 . More specifically, coupling  800  includes three engagement members, such as pins  804 , spaced about its circumference and configured and arranged to engage second housing portion  704 , as discussed below. In an alternative embodiment discussed herein, pins  804  are replaced with a plurality of rollers connected to coupling  800 . The use of rollers in place of pins is useful, for example, where coupling  800  is relatively large, and significant frictional forces must otherwise be overcome to operate coupling  800  in the manner described below. 
     In correspondence with pins  804 , second housing portion  704  includes three grooves  708 , each traversing an arc β of about one hundred twenty (120) degrees about the circumference of second housing portion  704 . The width and depth of grooves  708  generally correspond to the diameter and length, respectively, of pins  804 . In the illustrated embodiment, each groove  708  includes three connected portions, or segments. Specifically, each groove  708  includes an entry segment  708 A, an intermediate segment  708 B, and a terminal segment  708 C. In some alternative embodiments, grooves  708  are defined by a structure that is discrete from, but attached or attachable to, second housing portion  704 . In some embodiments, the terminal segment comprises a segment of a groove, other than the entry segment, that cooperates with a longitudinal axis such as axis AA (see, for example,  FIG. 8A ) to define an oblique angle. In yet other embodiments, the terminal segment may be generally perpendicular to a longitudinal axis (see, for example,  FIG. 12 ). Moreover, the number and arrangement of intermediate segments in a groove, or grooves, may be varied as/if desired (see, for example,  FIGS. 8A and 12 ). 
     It should be noted that the foregoing configuration is exemplary only and aspects such as, but not limited to, the size, number, geometry, arrangement, offset angle θ and arc length β (of grooves  708 ) and disposition of one or more of the embodiments of the pins and grooves disclosed herein, including pins  804  and grooves  708 , may be modified as necessary to suit the requirements of a particular application. Consistent with the foregoing, details concerning various alternative embodiments of grooves are set forth elsewhere herein (see  FIG. 12 ). Moreover, at least one embodiment of the invention includes four engagement members, examples of which include pins  804  and rollers  1106 A ( FIG. 10A ). 
     In general, the engagement of first housing portion  702  and second housing portion  704  is effected by positioning each pin  804  in a corresponding groove  708  and causing pins  804  to travel along grooves  708 , as suggested in  FIG. 8A . More particularly, first housing portion  702  and second housing portion  704  are brought together until each pin  804  of coupling  800  is positioned in the entry segment  708 A of a corresponding groove  708  of second housing portion  704 . Rotation of second housing portion  704  is then initiated, by way of handles  802 . As a result of the angular orientation of entry segments  708 A with respect to a longitudinal axis AA defined by the dry break valve assembly  700 , the initial rotation of first housing portion  702  causes second housing portion  704  to be drawn toward first housing portion  702 . 
     Continued rotation of first housing portion  702  causes pins  804  to complete their traverse of corresponding entry segments  708 A, and move into their respective intermediate segments  708 B. In at least some cases, pins  804  travel to the respective ends of intermediate segments  708 B. In any event, pins  804  remain in intermediate segments  708 B until such time as a predetermined pressure level is attained in a fluid passageway  1000  ( FIG. 9 ) collectively defined by first housing portion  702  and second housing portion  704 . 
     With continuing reference to  FIGS. 8 and 8A , and directing attention now to  FIG. 9 , details are provided concerning various operational aspects of an exemplary embodiment of dry break valve assembly  700 . As suggested above, the engagement of first housing portion  702  and second housing portion  704  results in the definition of a fluid passageway, generally denoted at  1000  in  FIG. 9 , and comprising portions  1000 A and  1000 B. 
     Prior to commencement of a fluid transfer operation, fluid is introduced into portion  1000 A, for example, by way of a conduit  106  ( FIG. 1 ) connected to first housing portion  702 , thereby pressurizing portion  1000 A. The pressure thus exerted, denoted at P 1  in  FIG. 10 , acts on the back of valve gate  304 A, which is in contact with sealing member  348  attached to first housing portion  702 . As a result of this arrangement of valve gate  304 A, sealing member  348 , and first housing portion  702 , the exertion of P 1  in this way causes first housing portion  702  to move slightly forward into closer engagement with second housing portion  704 , thereby forcing pins  804  to lock up into corresponding terminal segments  708 C of grooves  708 , as suggested in  FIG. 8A . 
     In the illustrated embodiment, the forward motion of first housing portion  702  may, depending on the position of pins  804  prior to pressurization of portion  1000 A, be accompanied by a rotary motion of first housing portion  702  as well, as pins  804  travel along intermediate segment  708 B and come to rest in terminal segment  708 C of groove  708 . Further, one or both of first housing portion  702  and second housing portion  704  may or may not rotate, depending upon whether one or both such portions  702  and  704  are otherwise restrained from rotational movement during the initial pressurization of portion  1000 A of fluid passageway  1000 . In yet other embodiments, little or no rotation of first housing portion  702  or second housing portion  704  occurs. 
     As suggested in  FIG. 8A , rotary motion of first housing portion  702 , at least, is facilitated, at least in part, by the geometric relation of intermediate segment  708 B with terminal segment  708 C, expressed as an offset angle θ. Specifically, as the action of pressure P 1  on the back of valve gate  304 A ( FIG. 9 ) causes first housing portion  702  to move forward into closer engagement with second housing portion  704 , the geometry that defines offset angle θ guides each pin  804  laterally, as well as forward, from the intermediate segment  708 B into its corresponding terminal segment  708 C. 
     Once pins  804  are seated thus, the continuing exertion of pressure P 1  on the back of valve gate  304 A aids in the retention of pins  804  in their corresponding terminal segments  708 C ( FIG. 8A ) and resists motion of pins  804  in the opposite direction, that is, out of their corresponding terminal segments  708 C. As a result, first housing portion  702  and second housing portion  704  of dry break valve assembly  700  cannot be disengaged from each other until the fluid pressure in portion  1000 A of fluid passageway  1000  has been reduced to a predetermined level or differential, or until the pressure in portions  1000 A and  1000 B has been equalized. Thus, the pins  804  and grooves  708  cooperate with each other, and advantageously employ the line pressure, to ensure a secure connection between first housing portion  702  and second housing portion  704  of dry break valve assembly  700  under a variety of pressure conditions. Note that the arrangement and configuration of pins  804  and grooves  708  in this exemplary embodiment, and others disclosed herein, may be varied to function in concert with either positive or negative (vacuum) pressures in fluid passageway  1000 . 
     Note further that a variety of means may be profitably employed to perform the functions, disclosed herein, of pins  804  and grooves  708 , and rollers  1106 A and grooves  1102 C discussed below. Examples of such functions include, but are not limited to, releasably engaging first and second elements of a fluid system component, maintaining engagement of such first and second elements so long as the line fluid pressure meets or exceeds a first predetermined value, and facilitating disengagement of such first and second elements when the line fluid pressure has reached a second predetermined value. Such first and second elements of a fluid system include, but are not limited to, first housing portion  702  and second housing portion  704  of dry break valve assembly  700 , and sleeve  1102  and collar  1106  of cap assembly  1100 . Thus, pins  804  and grooves  708 , and rollers  1106 A and grooves  1102 C, respectively, comprise exemplary structures that function as a means for releasable engagement. It should be understood that such structures are presented solely by way of example and should not be construed as limiting the scope of the present invention in any way. 
     While, in the foregoing discussion, various operational aspects of an exemplary embodiment of dry break valve assembly  700  are considered in the situation wherein a fluid processing operation is initiated by pressurization of portion  1000 A of fluid passageway  1000 , yet other fluid processing operations are commenced by initially pressurizing portion  1000 B of fluid passageway  1000 . As discussed below however, pins  804  and grooves  708  provide comparable functionality regardless of which portion of fluid passageway  1000  is initially pressurized. 
     In particular, fluid introduced into portion  1000 B of fluid passageway  1000  prior to commencement of a fluid transfer operation serves to pressurized portion  1000 B. The pressure thus exerted, denoted at P 2  in  FIG. 9 , acts on the back of valve gate  304 B, which is in contact with sealing member  350  attached to second housing portion  704 . As a result of this arrangement of valve gate  304 B, sealing member  350 , and second housing portion  704 , the exertion of P 2  in this way causes second housing portion  704  to move slightly forward into closer engagement with first housing portion  702 , thereby forcing terminal segments  708 C of grooves  708  into engagement with corresponding pins  804 , as suggested in  FIG. 8A . 
     Similar to the case where portion  1000 A is initially pressurized, the pressurization of portion  1000 B may, depending on the position of pins  804  and terminal segments  708 C prior to such pressurization, be accompanied by a rotary motion of second housing portion  704  as well, as terminal segments  708 C of groove  708  travel into a position where they can engage corresponding pins  804 . Of course, one or both of first housing portion  702  and second housing portion  704  may or may not rotate, depending upon whether one or both such portions  702  and  704  are otherwise restrained from rotational movement during the initial pressurization of portion  1000 B of fluid passageway  1000 . In any event, initial pressurization of portion  10001 B will operate, in substantially the same fashion as initial pressurization of portion  1000 A, with respect to the engagement of first housing portion  702  with second housing portion  704 . 
     While the immediately preceding discussion is concerned with a specific type of fluid system component, that is, a dry break valve, embodiments of the invention are directed, more generally, to any fluid system component having portions, or elements, which are desired to be releasably engaged. One exemplary embodiment of such a fluid system component is considered below. 
     Directing attention now to  FIGS. 10 through 10B , details are provided concerning an exemplary embodiment of a cap assembly, generally denoted at  1100 . In the illustrated embodiment, cap assembly  1100  generally includes a sleeve  1102 , configured to receive the end of a fluid conduit  1200 , a cap  1104  configured to be positioned on the end of fluid conduit  1200  and cooperating with fluid conduit  1200  to at least partially define a fluid passageway  1300  when so positioned, and a collar  1106  generally configured to retain cap  1104  in position. 
     More particularly, sleeve  1102  defines a socket  1102 A having an inside diameter of dimension ID compatible with the outside diameter dimension OD of fluid conduit  1200 . It is desirable in some cases to construct sleeve  1102  in such a way that a gap is introduced between the inside of socket  1102 A and fluid conduit  1200  so as to accommodate, for example, any differences in the thermal expansion rates of sleeve  1102  and fluid conduit  1200 . The sleeve  1102  may be attached to fluid conduit  1200  in any suitable manner, such as by methods including, but not limited to, welding, brazing and soldering. In at least one embodiment, sleeve  1102  and fluid conduit  1200  each include mating threads so that sleeve  1102  can be removably attached to fluid conduit  1200 . 
     Generally, sleeve  1102  comprises a metallic material that, in at least some instances, is chemically and thermally compatible with fluid conduit  1200 . Exemplary materials for sleeve  1102  include, but are not limited to, copper and its alloys, steels, iron, aluminum and its alloys, and titanium and its alloys. Moreover, sleeve  1102  may be machined or cast. Other suitable construction methods may alternatively be employed. 
     With continuing reference to its various geometric features, sleeve  1102  further includes a substantially annular chamfer  1102 B that defines an opening wherein a portion of cap  1104  is received, as indicated in  FIG. 10A . Generally, the geometry of chamfer  1102 B is configured to correspond to the structure of cap  1104  with which it interfaces. Geometric aspects of chamfer  1102 B such as, but not limited to, the wall thickness and chamfer angle may be adjusted as necessary to suit the requirements of a particular application. 
     As further indicated in  FIG. 10A , sleeve  1102  defines a plurality of grooves  1102 C that are configured and arranged to engage corresponding structure of coupling  1106 , discussed in further detail below. In particular, and directing attention now to  FIG. 10B  as well, each groove  1102 C includes three connected segments, an entry segment  1102 D, an intermediate segment  1102 E, and a terminal segment  1102 F. Such grooves may be machined, or otherwise formed, in the outer surface of sleeve  1102  and, in one embodiment, each describes an arc β of about one hundred twenty (120) degrees about the circumference of sleeve  1102 . In the case of other exemplary embodiments, such as that illustrated in  FIG. 12  for example, arc β described by each groove may be such that the grooves overlap each other. Similar to other exemplary embodiments of grooves disclosed herein, intermediate segment  1102 E and terminal segment  1102 F cooperate to define an offset angle δ that aids in the engagement of collar  1106  with sleeve  1102  generally in the manner described elsewhere herein. 
     It should be noted that the embodiment of grooves  1102 C illustrated in  FIG. 10B  is exemplary only and aspects of grooves  1102 C such as, but not limited to, the size, number, geometry, arrangement, arc length β, offset angle δ, and disposition of one or more of grooves  1102 C may be varied in accordance with the requirements of a particular application. Accordingly, such exemplary embodiment should not be construed to limit the scope of the invention in any way. 
     In correspondence with the grooves  1102 C defined by sleeve  1102 , collar  1106  includes a plurality of rollers  1106 A, each of which is configured and arranged to be received within a corresponding groove  1102 C and to travel therealong, as suggested by the exemplary roller travel paths illustrated in  FIG. 10B . To that end, each roller  1106 A has a diameter and thickness that generally correspond with the width and depth, respectively, of a corresponding groove  1102 C. As indicated in  FIG. 10A , the rollers  1106 A are disposed within the interior of collar  1106  and are each attached to a corresponding fastener  1106 B that passes through collar  1106 . Each of the fasteners  1106 B is secured in position by a corresponding nut  1106 C, and the extent to which rollers  11106 A protrude into the interior of collar  1106  may be changed by adjusting the positioning of nuts  1106 C accordingly. In some embodiments of the invention, bearings or similar structures or devices are provided to facilitate ready and reliable rotation of the rollers  11106 A. 
     With continuing attention to  FIG. 10A , further details are provided concerning aspects of collar  1106 . In particular, collar  1106  defines a sealing surface  1106 D that cooperates with O-ring  1108  to substantially prevent fluid leakage from the joint cooperatively defined by cap  1104  and collar  1106 , as well as from the joint cooperatively defined by cap  1104  and sleeve  1102 . As suggested by the foregoing, and as illustrated in  FIG. 10A , the exemplary embodiment of collar  1106  is substantially hollow and is configured to receive cap  1104  in such a way as to substantially prevent material axial or radial movement of cap  1104  when collar  1106  has fully engaged sleeve  1102 , as shown in  FIG. 10A . 
     In the illustrated embodiment, cap  1104  and collar  1106  comprise discrete structures. However, in an alternative embodiment, cap  1104  and collar  1106  are integral with each other, or otherwise permanently joined to each other, and an O-ring or other sealing device is interposed between cap  1104  and sleeve  1102 . The foregoing arrangements are, however, exemplary only and are not intended to limit the scope of the invention. 
     With continuing reference to  FIGS. 10 through 10B , and directing attention now to  FIGS. 11A through 11C , cap assembly  1100  further includes one or more handles  1110  that permit a user to impart a rotary motion so as to engage ( FIG. 11B ), or disengage ( FIG. 11A ), collar  1106  and sleeve  1102 . The handles  1106 E may comprise steel bar stock or any other suitable materials and/or configurations. In at least one embodiment, aspects of which are illustrated in  FIG. 11C , each of handles  1110  are rotatably attached, by way of pins  1112 , to corresponding blocks  1114  joined to collar  1106  so that handles  1110  can be rotated, as indicated, from a use position upward into a storage position when not needed, and vice versa. Moreover, some embodiments include one or more stops  1115  which serve to prevent over-rotation of collar  1106 . In the embodiment illustrated in  FIG. 10A , stops  1115  comprise bolts that pass through collar  1106 . However, any other suitable arrangement or structure providing similar functionality may alternatively be employed. 
     As further indicated in  FIGS. 10A ,  11 A and  11 B, cap assembly  1100  further includes an alignment tab  1116 , which is attached to sleeve  1102  and/or fluid conduit  1200 , or otherwise suitably located. In the illustrated embodiment, alignment tab  1116  defines an opening  1116 A positioned to be aligned with a corresponding opening  1106 B 1  defined by one of the fasteners  1106 . At such time as an opening  1106 B 1  is substantially aligned with opening  1116 A in a way that corresponds to a desired position of handles  1110 , a tamper-evident device  1118  comprising, for example, a thin wire  1118 A that can be threaded through the aligned holes and securely fastened with a lead seal  1118 B so that an observer can readily determine if the position of handles  1110  has been changed subsequent to placement of the tamper-evident device  1118 . 
     Moreover, and as suggested above, alignment tab  1116  is positioned so as to provide feedback to the operator as to whether or not collar  1106  and sleeve  1102  are fully engaged with each other. In particular, and as indicated in  FIG. 11A , collar  1106  is initially positioned so that a fastener  1106  is disposed on either side thereof. As collar  1106  is rotated to the fully engaged position, illustrated in  FIG. 11B , the hole  1116 A of alignment tab  1116  is aligned with a corresponding hole  1106 B 1  of a fastener  1106 B. Consequently, an operator can readily make a visual determination as to whether or not collar  1106  and sleeve  1102  are fully engaged with each other. 
     In some embodiments, cap assembly  1100  additionally includes a safety restraint  1120  comprising a cable  1120 A and cable crimps  1120 B. In an exemplary embodiment, cable  1120 A comprises a one eighth (0.125) inch diameter steel cable looped through at least one handle  1110  and around fluid conduit  1200 , and retained in place by cable crimps  1120 B, as shown in  FIG. 10A . Generally, safety restraint  1120  operates as a redundant safety system that serves to prevent, or reduce, damage to personnel or surrounding equipment and systems in the event collar  1106  becomes disconnected, in an uncontrolled manner, from sleeve  1102 . 
     With attention now to  FIGS. 10 through 11C , details are provided concerning various operational aspects of the illustrated embodiment. As such operational aspects are similar in many regard to those discussed elsewhere herein with respect to various alternative embodiments, the following discussion will focus primarily on selected operational aspects of the embodiment illustrated in  FIGS. 10 through 11C . 
     In operation, the engagement of collar  1106  and sleeve  1102  is effected by positioning each roller  1106 A in a corresponding groove  1102 C and causing rollers  1106 A to travel along grooves  1102 C according to the path denoted in  FIG. 10B . More particularly, collar  1106  and sleeve  1102  are brought together until each roller  1106 A of collar  1106  is positioned in the entry segment  1102 D of a corresponding groove  1102 C of sleeve  1102 . Rotation of collar  1106  is then initiated by way of handles  1110 . As a result of the angular orientation of entry segments  1102 D with respect to a longitudinal axis BB defined by the cap assembly  1100 , the initial rotation of collar  1106  causes collar  1106  to be drawn toward sleeve  1102 , confining cap  1104  therebetween. 
     Continued rotation of collar  1106  causes rollers  1106 A to complete their traverse of corresponding entry segments  1102 D, and move into their respective intermediate segments  1102 E. In at least some cases, rollers  1106 A travel to the respective ends of terminal intermediate  1102 E. In any event, rollers  1106 A remain in intermediate segments  1102 E until such time as a predetermined pressure level is attained in a fluid passageway  1300  ( FIG. 10A ) collectively defined by cap  1104  and fluid conduit  1200 . 
     Subsequently, fluid is introduced into fluid passageway  1300 , by way of fluid conduit  1200  ( FIG. 10A ) connected with cap assembly  1100 , thereby pressurizing portion fluid passageway  1300 . The pressure thus exerted, denoted at P 3  in  FIG. 10A , transmits a force to cap  1104  which, in turn, transmits the force to collar  1106 . Consequently, the exertion of P 3  in this way forces rollers  1106 A, attached to collar  1106 , to lock up into corresponding terminal segments  1102 F of grooves  1102 C and remain therein, as indicated in  FIG. 10A . 
     In the illustrated embodiment, the forward motion of collar  1106  may, depending on the position of rollers  1106 A at the time of pressurization of fluid passageway  1300 , be accompanied by a rotary motion of collar  1106  as well, as rollers  1106 A travel along intermediate segments  1102 E and come to rest in terminal segment  1102 F of groove  1102 C. Generally, such rotary motion of collar  1106  is achieved in the substantially the same way as the rotary motion of first housing portion  702 , discussed above. 
     Once rollers  1106 A are seated in their corresponding terminal segments  1102 F of grooves  1102 C, the continuing presence of pressure P 3  exerts a force on cap  1104  that resists motion of rollers  1106 A in the opposite direction, i.e., out of their corresponding terminal segments  1102 F, and thereby aids in the retention of rollers  1106 A in such terminal segments. As a result, collar  1106  and sleeve  1102  of cap assembly  1100  cannot be disengaged from each other until the fluid pressure in fluid passageway  1300  has been reduced to a predetermined level or differential. 
     Thus, the rollers  1106 A and grooves  1102 C cooperate with each other, and advantageously employ the line pressure, to ensure a secure connection between collar  1106  and sleeve  1102  of cap assembly  1100  subsequent to pressurization of fluid passageway  1300 . Thus, the likelihood of inadvertent, or intentional, removal of cap  1104  while a potentially dangerous level of pressure exists in fluid passageway  1300 , is materially reduced. 
     Directing attention now to  FIG. 12 , details are provided concerning an alternative embodiment of a groove arrangement including a plurality of grooves generally denoted at  1400 . Note that in the interest of clarity, the generally cylindrical structural element wherein the grooves  1400  are formed is shown flat, rather than in a perspective view. Similar to other embodiments of grooves disclosed herein, groove  1400  includes a plurality of segments, including an entry segment  1400 A. In contrast with such other embodiments however, groove  1400  further includes four intermediate segments denoted, respectively,  1400 B,  1400 C,  1400 D and  1400 E as well as a terminal segment  1400 F. Moreover, in embodiments of the invention employing configurations such as grooves  1400 , the final resting position of the associated rollers (not shown), that is, after the associated fluid passageway has been pressurized, is in terminal segment  1400 F, rather than in one of the intermediate segments  1400 B and  1400 C. 
     Although in the exemplary embodiment illustrated in  FIG. 12 , grooves  1400  are illustrated that include four intermediate segments, one or more aspects of grooves  1400  may be varied as necessary to suit a particular application. For example, intermediate segments  1400 B,  1400 D and  1400 F are, in some embodiments, generally parallel to each other. In yet other embodiments, such intermediate segments are disposed in a non-parallel arrangement. The same is likewise true with respect to segments  1400 A,  1400 C and  1400 E. Moreover, other features such as, but not limited to, the length, width and depth of one or more grooves  1400  may be modified as required/desired. 
     It should thus be noted that the foregoing, and other, arrangements of grooves, as well as the type and arrangement of their associated engagement members, disclosed herein are exemplary only and are not intended to limit the scope of the invention. By way of example, in another exemplary embodiment (not shown), one or more of such grooves substantially describes a “J” shape, such that line pressure causes the corresponding engagement member to lock into a location proximate the end of the “hook” portion of the “J” shaped groove. 
     Directing attention now to  FIGS. 13 and 13A , details are provided concerning an exemplary embodiment of a cap assembly, generally denoted at  1100 . In the illustrated embodiment, cap assembly  1100  generally includes a sleeve  1102 , configured to receive the end of a fluid conduit  1200 , a cap  1104  configured to be positioned on the end of fluid conduit  1200  and cooperating with fluid conduit  1200  to at least partially define a fluid passageway  1300  when so positioned, and a collar  1106  generally configured to retain cap  1104  in position. 
     More particularly, sleeve  1102  defines a socket  1102 A having an inside diameter of dimension ID compatible with the outside diameter dimension OD of fluid conduit  1200 . It is desirable in some cases to construct sleeve  1102  in such a way that a gap is introduced between the inside of socket  1102 A and fluid conduit  1200  so as to accommodate, for example, any differences in the thermal expansion rates of sleeve  1102  and fluid conduit  1200 . The sleeve  1102  may be attached to fluid conduit  1200  in any suitable manner, such as by methods including, but not limited to, welding, brazing and soldering. In at least one embodiment, sleeve  1102  and fluid conduit  1200  each include mating threads so that sleeve  1102  can be removably attached to fluid conduit  1200 . 
     Generally, sleeve  1102  comprises a metallic material that, in at least some instances, is chemically and thermally compatible with fluid conduit  1200 . Exemplary materials for sleeve  1102  include, but are not limited to, copper and its alloys, steels, iron, aluminum and its alloys, and titanium and its alloys. Moreover, sleeve  1102  may be machined or cast. Other suitable construction methods may alternatively be employed. 
     With continuing reference to its various geometric features, sleeve  1102  further includes a substantially annular chamfer  1102 B that defines an opening wherein a portion of cap  1104  is received, as indicated in  FIG. 13A . Generally, the geometry of chamfer  1102 B is configured to correspond to the structure of cap  1104  with which it interfaces. Geometric aspects of chamfer  1102 B such as, but not limited to, the wall thickness and chamfer angle may be adjusted as necessary to suit the requirements of a particular application. 
     As further indicated in  FIG. 13A , sleeve  1102  defines a plurality of grooves  1102 C that are configured and arranged to engage corresponding structure of coupling  1106 . In particular, as described above with reference to  FIG. 10B , each groove  1102 C includes three connected segments, an entry segment  1102 D, an intermediate segment  1102 E, and a terminal segment  1102 F. Such grooves may be machined or otherwise formed in the outer surface of sleeve  1102  and, in one embodiment, each describes an arc β of about one hundred twenty (120) degrees about the circumference of sleeve  1102 . In the case of other exemplary embodiments, such as that illustrated in  FIG. 12  for example, arc β described by each groove may be such that the grooves overlap each other. Similar to other exemplary embodiments of grooves disclosed herein, intermediate segment  1102 E and terminal segment  1102 F cooperate to define an offset angle δ that aids in the engagement of collar  1106  with sleeve  1102  generally in the manner described elsewhere herein. 
     It should be noted that the embodiment of grooves  1102 C illustrated in  FIG. 10B  is exemplary only and aspects of grooves  1102 C such as, but not limited to, the size, number, geometry, arrangement, arc length β, offset angle δ, and disposition of one or more of grooves  1102 C may be varied in accordance with the requirements of a particular application. Accordingly, such exemplary embodiment should not be construed to limit the scope of the invention in any way. 
     In correspondence with the grooves  1102 C defined by sleeve  1102 , collar  1106  includes a plurality of rollers  1106 A, each of which is configured and arranged to be received within a corresponding groove  1102 C and to travel therealong, as suggested by the exemplary roller travel paths illustrated in  FIG. 10B . To that end, each roller  1106 A has a diameter and thickness that generally correspond with the width and depth, respectively, of a corresponding groove  1102 C. As indicated in  FIG. 10A , the rollers  1106 A are disposed within the interior of collar  1106  and are each attached to a corresponding fastener  1106 B that passes through collar  1106 . Each of the fasteners  1106 B is secured in position by a corresponding nut  1106 C, and the extent to which rollers  1106 A protrude into the interior of collar  1106  may be changed by adjusting the positioning of nuts  1106 C accordingly. In some embodiments of the invention, bearings or similar structures or devices are provided to facilitate ready and reliable rotation of the rollers  1106 A. 
     As illustrated in  FIG. 13A , sleeve  1102  defines a pin aperture  1102 G formed in the wall of the sleeve  1102  configured to receive an end of a pin  1130  therein, as described more fully hereinafter. In the illustrated embodiment, the pin aperture  1102 G extends partially through the wall of the sleeve  1102 . However, it is appreciated that the pin aperture  1102 G may extend completely through the sleeve  1102  so as to form a hole through a portion of the sleeve  1102 . The pin aperture  1102  is sized and configured to receive a portion of the pin  1130  therein, and positioned in the sleeve  1102  so as to align with a pin aperture  1106 F in the collar  1106  when collar  1106  has fully engaged sleeve  1102 , as illustrated in  FIG. 13A . 
     With continuing attention to  FIG. 13A , further details are provided concerning aspects of collar  1106 . In particular, collar  1106  defines a sealing surface  1106 D that cooperates with O-ring  1108  to substantially prevent fluid leakage from the joint cooperatively defined by cap  1104  and collar  1106 , as well as from the joint cooperatively defined by cap  1104  and sleeve  1102 . As suggested by the foregoing, and as illustrated in  FIG. 13A , the exemplary embodiment of collar  1106  is substantially hollow and is configured to receive cap  1104  in such a way as to substantially prevent material axial or radial movement of cap  1104  when collar  1106  has fully engaged sleeve  1102 , as shown in  FIG. 13A . 
     As illustrated in  FIG. 13A , collar defines a pin aperture  1106 F. In one embodiment, the pin aperture  1106 F is formed through the wall of the collar  1106 . The pin aperture  1106 F is sized and configured to receive a portion of the pin  1130  there through. The pin aperture  1106 F is further sized and configured so as to allow the shaft  1130 B of the pin  1130  to rotate and translate within the pin aperture  1106 F. The pin aperture  1106 F is positioned in collar  1106  so as to be substantially aligned with the pin aperture  1102 G of sleeve  1102  when collar  1106  has fully engaged sleeve  1102 , as show in  FIG. 13A . For example, the pin aperture  1106 F is substantially aligned with the pin aperture  1102 G when a pin, for example, can be received in the pin aperture  1102 G of the sleeve  1102  through the pin aperture  1106 F of the collar  1106 , as illustrated in  FIG. 13A . 
     With continued reference to  FIG. 13A , cap assembly  1100  further includes a pin  1130  configured to substantially prevent axial rotation of collar  1106  with respect to sleeve  1102  when pin  1130  is positioned in pin apertures  1102 G and  1106 F. In the illustrated embodiment, the pin  1130  includes a head  1130 A coupled to a shaft  1130 B. The head  1130 A may be configured to enable a user to grip the pin  1130  and selectively move the pin  1130 , such as to remove the pin  1130  from the pin apertures  1102 G and  1106 F or to insert the pin  1130  in the pin apertures  1102 G and  1106 F. For example, the head  1130 A may be sized and/or shaped to accommodate a particular user, or to accommodate a particular size of fluid conduit. It may be useful for the head to be larger if the fluid conduit is larger or smaller if the fluid conduit is smaller. 
     As illustrated in  FIG. 13A , the shaft  1130 B is coupled to the head  1130 A so as to cause the shaft  1130 B to move as the head  1130 A moves. In this manner, as the head  1130 A is moved away from the collar  1106 , the shaft  1130 B naturally follows and moves in the direction of the head  1130 A, such as when a user grips the head  1130 A and moves it in a direction away from the pin apertures  1102 G and  1106 F the shaft  1130 B is removed from pin apertures  1102 G and  1106 F. The shaft  1130 B includes a proximal end adjacent the head  1130 A of the pin  1130  and an opposing distal end. As illustrated in  FIG. 13A , the proximal end of the shaft  1130 B is configured to be received and movable in the pin aperture  1106 F of the collar  1106 . The opposing distal end of the shaft  1130 B is configured to be received and movable in the pin aperture  1102 G of the sleeve  1102 . In this manner, shaft  1130 B can be positioned in both pin apertures  1102 G and  1106 F to substantially prevent axial rotation of the collar  1106  with respect to the sleeve  1102 . 
     The pin  1130  can be held in position by a number of mechanisms. For example, the pin  1130  may be biased into the position illustrated in  FIG. 13A  by use of a spring or resilient member. Alternatively, the pin  1130  may be biased through an interference fit between the shaft  1130 B of the pin  1130  and one or more of the pin apertures  1102 G and  1106 F. Also, the pin apertures  1102 G and  1106 F may be positioned in the sleeve  1102  and collar  1106 , respectively, such that when the fluid conduit  1200  is stationary the pin apertures  1102 G and  1106 F face upwards thus allowing gravity to influence the positioning of the pin  1130 . 
     The pin  1130  is selectively removable so as to enable axial rotation of the collar  1106  with respect to the sleeve  1102 . For example, the ability of the pin  1130  to move in the pin apertures  1102 G and  1106 F enables the pin  1130  to be selectively removable. In at least one embodiment, the pin  1130  can be completely removed from both the pin apertures  1102 G and  1106 F by a user to enable axial rotation of the collar  1106  with respect to the sleeve  1102 . Alternatively, the pin  1130  can be removed, selectively by a user, by moving the pin  1130  such that the distal end of the shaft  1130 B is no longer received in the pin aperture  1102 G of the sleeve  1102 , thus enabling axial rotation of the collar  1106  with respect to the sleeve  1102 . The collar  1106  can be selectively secured to the sleeve  1102  by a user positioning the pin  1130  in the pin apertures  1102 G and  1102 F sufficient to substantially prevent axial rotation of the collar  1106  with respect to the sleeve  1102 . 
     The pin  1130  is one example of means for selectively securing the collar  1106  with respect to the sleeve  1102  when the collar  1106  receives at least a portion of the sleeve  1102  therein, as illustrated in  FIG. 13A . Another example of means for selectively securing includes a threaded shaft or bolt that is received through a corresponding aperture in the collar  1106  and screwed or otherwise secured into a threaded aperture in the sleeve  1102 . Another example of a means for selectively securing includes the use of a friction fit between the collar  1106  and the sleeve  1102 , such as a clamp that squeezes the collar  1106  to the sleeve  1102  such that an inner surface of the collar  1106  engages an outer surface of the sleeve  1102  sufficient to substantially prevent axial rotation of the collar  1106  with respect to the sleeve  1102 . 
     Axial rotation of the collar  1106  with respect to the sleeve  1102  is substantially reduced when the pin  1130  is positioned in pin apertures  1102 G and  1106 F. The shape and size of the pin apertures  1102 G and  1106 F substantially corresponds with the shape and size of the shaft  1130 B of the pin  1130 . When positioned in the pin apertures  1102 G and  1106 F, the pin  1130  serves as a means of interference to the collar  1106  being able to axially rotate about the sleeve  1102 . In this manner, the pin  1130  links the collar  1106  to the sleeve  1102  to substantially prevent axial rotation of the collar  1106  with respect to the sleeve  1102 . 
     It is appreciated that the shape and size of the pin  1130  may not exactly correspond with the shape and size of the pin apertures  1102 G and  1106 F, which may result in a small degree of “slack” in the securement of the collar  1106  with respect to the sleeve  1102 . This small degree of “slack” may allow the collar  1106  to rotate slightly about the sleeve  1102 . However, the degree of rotation would not be enough to allow the collar  1106  to be rotated off of the sleeve  1102 . Furthermore, it will be appreciated that with sufficient force the pin  1130  may be sheared and severed when positioned in pin apertures  1102 G and  1106 F such that the collar  1106  can rotate about the sleeve  1102 . Typically, however, such sufficient force would not be exerted on the pin  1130 , thus allowing the pin  1130  to substantially prevent axial rotation of the collar  1106  with respect to the sleeve  1102 . 
     In the illustrated embodiment, cap  1104  and collar  1106  comprise discrete structures. However, in an alternative embodiment, cap  1104  and collar  1106  are integral with each other, or otherwise permanently joined to each other, and an O-ring or other sealing device is interposed between cap  1104  and sleeve  1102 . The foregoing arrangements are exemplary only, however, and are not intended to limit the scope of the invention. 
     Cap assembly  1100  may include one or more handles  1110  and/or one or more stops  1115  as described herein above with reference to  FIGS. 11A-11C . Furthermore, cap assembly  1100  may include one or more alignment tabs  1116  as described with reference to  FIGS. 10A ,  11 A and  11 B. Additionally, cap assembly  1100  may include a safety restraint  1120  as described herein above. 
     The operational aspects of the embodiment illustrated in  FIG. 13A  are substantially similar to the operation aspects as described herein above with reference to  FIGS. 10 through 11C . However, it should be appreciated that prior to collar  1106  receiving a portion of the sleeve  1102  therein, the distal end of the shaft  1130 B of the pin  1130  should not extend beyond the inner surface of the collar  1106 . Once the collar  1106  is in position such that fluid can be introduced into the fluid conduit  1200 , the distal end of shaft  1130 B can be positioned in pin aperture  1102 G of the sleeve  1102  so as to substantially prevent axial rotation of the collar  1106  with respect to the sleeve  1102 . It is appreciated that the pin aperture  1102 G of the sleeve  1102  may extend at least partially along the length of the sleeve such that as pressure is introduced in the fluid conduit  1200  the rollers  1106 A, attached to collar  1106 , are able to move and lock up into corresponding terminal segments  1102 F of grooves  1102 C and remain therein, as indicated in  FIG. 10A . 
     In light of the disclosure herein, it will be appreciated by one of ordinary skill in the art that a coupling, such as cap assembly  1100  of  FIGS. 10A through 11B , can comprise one or more handles located in any of various positions and configurations. For example, in the exemplary embodiment illustrated in  FIGS. 14A through 14C , an exemplary coupling  1101  is illustrated, which includes a coupling handle  1110 A that extends around the entire circumference of collar  1106 , although as shown in  FIG. 13 , a coupling handle does not need to extend fully around collar  1106 . In the embodiment illustrated in  FIG. 14A , coupling handle  1110 A further comprises support members  1110 B that connect handle  1110 A to collar  1106 . Support members  1110 B can be attached to handle portion  1110 A and collar  1106  in a variety of ways including, but not limited to, welding, brazing, soldering, and the like. Alternatively, handle portion  1110 A, support members  1110 B, and/or collar  1106  can be formed as an integral piece, or attached or formed in any other suitable manner. 
     Coupling  1101 , illustrated in  FIGS. 14A through 14C , further comprises in this embodiment pin handle  1130 C, which can be directly or indirectly coupled to the proximate end of pin  1130 . Pin handle  1130 C can be slideably or fixedly coupled to pin  1130  in a manner that links movement of pin  1130  and pin handle  1130 C. For example, as a user exerts a force on pin handle  1130 C so as to extend it in a proximal direction, pin  1130  can also be caused to correspondingly move in a proximal direction. Pin handle  1130 C can thus be configured to enable a user to grip pin handle  1130 C and thereby selectively move pin  1130 . Movement of pin  1130  in this manner may, for example, remove pin  1130  from pin apertures  1102 G ( FIG. 13A ) of sleeve  1102  and/or from apertures  1106 F ( FIG. 13A ) of collar  1106 . Similarly, movement of pin  1130  in an opposite direction may insert pin  1130  into pin aperture  1102 G and/or pin aperture  1106 F. 
     In some embodiments, pin handle  1130 C is coupled to the proximate end of pin  1130 , thus eliminating the need for pin head  1130 A. Alternatively, pin handle  1130 C can be coupled to pin head  1130 A, while pin head  1130 A is in turn is coupled to the proximate end of pin  1130 . As a result, coupling pin handle  1130 C can be indirectly coupled to pin  1130 . In other alternative embodiments, pin  1130  and pin handle  1130 C are formed as a single, integral piece. In any configuration, pin handle  1130 C can be either directly or indirectly coupled to pin  1130  such that inward or outward movement of pin handle  1130 C correspondingly moves pin  1130  inward or outward. 
     As illustrated in  FIGS. 14A through 14C , pin handle  1130 C may extend around only portion of the circumference of collar  1106 . In the illustrated embodiment, for example, pin handle  1130 C defines an arc of about one hundred twenty (120) degrees. However, the arc defined by pin handle  1130 C can be larger or smaller than one hundred twenty (120) degrees. For example, in other embodiments, pin handle  1130 C defines an arc of about sixty (60) degrees, about ninety (90) degrees, or about one hundred eighty (180) degrees. Other aspects, characteristics, functions, and the like, of pin  1130 , pin apertures  1102 G and  1106 F ( FIG. 13A ), and pin head  1130 A as described elsewhere herein can apply equally to the present embodiment. For example, pin  1130  can, in some embodiments, be biased in a manner similar to that described above with respect to  FIG. 13A . 
     In the example embodiment of  FIGS. 14A-C , coupling handle  1110 A and pin handle  1130 C are positioned adjacent to each other. More particular, in the illustrated embodiment, a recess of about the shape of pin handle  1130 C is formed in coupling handle  1110 , and coupling handle  1110 A is positioned such that it generally corresponds with the recess. Accordingly, coupling handle  1110 A and pin handle  1130 C can have a stacked or nested arrangement. In other embodiments, however, coupling handle  1110  may not be configured to receive pin handle  1130 C, and coupling handle  1110 A and pin handle  1130 C may merely be placed proximate each other. In either such embodiment, coupling handle  1110 A and pin handle  1130 C are positioned such that a user can simultaneously grip both coupling handle  1110  and pin handle  1130 C with either one or two hands. 
     In the illustrated embodiment, a radius from a central, longitudinal axis of collar  1106  to coupling handle  1110 A can be definite and unchanging. The radius from the longitudinal axis to pin handle  1130 C may, however, vary. For example, pin handle  1130 C may, in its innermost position, have a radius slightly smaller than the fixed radius of coupling handle  1110 A, although in other embodiments pin handle  1130 C has a radius about equal to, or larger, than coupling handle  1110 A. As described herein, the innermost position of pin handle  1130 C can correspond to a biased position of pin  1130 . 
     As discussed above, pin  1130  can move with respect to pin apertures  1102 G and  1106 F ( FIG. 13A ) and may be withdrawn at least partially therefrom. When pin  1130  is connected to pin handle  1130 C, this may occur by exerting a force which pulls pin handle  1130 C away from collar  1106 . Because pin  1130  can be withdrawn from pin apertures  1102 G and  1106 F ( FIG. 13A ), by pulling pin handle  1130 C away collar  1106  the distance between pin handle  1130 C and the central axis of collar  1106  can increase. Accordingly, in one embodiment, the radius between the central, longitudinal axis of collar  1106  and pin handle  1130 C can increase to a radius about equal to, or greater than, the radius of coupling handle  1110 . In one embodiment, when pin handle  1130 C is diametrically aligned within coupling handle  1110 , pin  1130  is withdrawn from pin aperture  1102 G ( FIG. 13A ). In some embodiments, pin handle  1130 C and pin  1130  can be entirely withdrawn from both pin apertures  1102 G and  1106 F ( FIG. 13A ). 
     As noted above, various configurations of a pin aperture are envisioned within the scope of the present invention. One such configuration is illustrated in  FIG. 10B  in which pin aperture  1102 G can comprise a terminal segment  1102 F of groove  1102 C. When pin  1130  is positioned in pin aperture  1102 G and/or terminal segment  1102 F, rollers  1106 A may be aligned with, and optionally positioned in, intermediate segment  1102 E. In some embodiments, pin aperture  1102 G and terminal segment  1102 F constitute the same recess within sleeve  1102 . 
     Various operational aspects of the coupling embodiment illustrated in  FIGS. 14A through 14C  are similar to the operational aspects as described herein above with reference to the cap assembly of  FIGS. 10-11C  and  FIGS. 13-13A . Accordingly, features of the cap assemblies of  FIGS. 10-11C  and  FIGS. 13-13A , and the coupling of  FIGS. 14A-C  may be interchangeable. For example, with reference to the example embodiment of  FIGS. 14A-C , for collar  1106  to receive a portion of sleeve  1102  ( FIG. 13A ) therein, the distal end of shaft  1130 B ( FIG. 13A ) of pin  1130  can be positioned such that it does not extend past the inner surface of collar  1106 . While simultaneously gripping coupling handle  1110 A and pin handle  1130 C, a user can pull pin handle  1130 C proximally, and away from collar  1106 , to withdraw the distal end of shaft  1130 B such the distal end of shaft  1130 B is also positioned proximally relative to the inner surface of collar  1106 . Thus, the distal end of shaft  1130 B can be withdrawn such that it does not extend into shaft  1130 B. With pin  1130  retracted such that the distal end of shaft  11301 B does not extend distally past the inner surface of collar  1106 , the user can reposition collar  1106  relative to sleeve  1102  using coupling handle  1110 A to engage collar  1106  and sleeve  1102  as described elsewhere herein. Once collar  1106  and sleeve  1102  are engaged such that fluid can be introduced into the fluid conduit  1200 , the user can release handle  1130 C, thereby allowing pin  1130  to move distally, and to position the distal end of shaft  1130 B of pin  1130  in pin aperture  1102 G ( FIG. 13A ) of sleeve  1102 . With the distal end of shaft  1130 B positioned in pin apertures  1102 G and  1106 F ( FIG. 13A ), axial rotation of collar  1106  relative to sleeve  1102  can be substantially prevented, and collar  1106  can be substantially locked in place relative to sleeve  1102 . 
     As will be appreciated by one of ordinary skill in the art in view of the disclosure herein, if pin  1130  is withdrawn from pin aperture  1102 G before the pressure within fluid conduit  1200  is released, the pressure in fluid conduit  1200  will press against collar  1106 . In embodiments of a coupling member having rollers  1106 A, such as described with respect to  FIGS. 10-11C , such pressure can cause rollers  1106 A to move along grooves  1102 C toward entry segment  1102 D. Without terminal segment  1102 F, rollers  1106 A could exit groove  1102 C, thereby resulting in disengagement of collar  1106  and sleeve  1102 . Disengagement of collar  1106  and sleeve  1102  while fluid conduit  1200  is still under pressure can result in numerous problems. For instance, fluid can leak into the environment and/or the fluid pressure may forcibly cause the fluid coupling member to become dislodged from fluid conduit  1200 . The fluid coupling member may then uncontrollably fly off fluid conduit  1200  and hit an operator or user, or the fluid itself my forcibly exit and contact a user, thereby causing serious bodily injury. 
     Notably, when terminal segment  1102 F ( FIG. 10B ) is employed, such problems can be entirely or largely prevented. Specifically, if pin  1130  is withdrawn from pin aperture  1102 G ( FIG. 13A ) while fluid passageway is under pressure, rollers  1106 A will begin to move along grooves  1102  towards entry segments  1102 F; however, before reaching entry segment  1102 D, rollers  1106 A will encounter and engage terminal segments  1102 F as described above. The groove geometry of terminal segments  1102 F is configured to use the line pressure in such a way to prevent further movement of rollers  1106 A, and thus also prevent disengagement of collar  1106  and sleeve  1102 . Once the pressure in fluid conduit  1200  is released, the line pressure can be overcome and a user will be able to disengage rollers  1106 A from terminal segment  1102 F. Once rollers  1106 A are disengaged from terminal segment  1102 F, collar  1106  and sleeve  1102  can be safely disengaged. 
     While the foregoing example illustrated an example embodiment in which the line pressure is released before rollers  1106 A can be removed from terminal segment  1102 F, it will be appreciated in view of the disclosure herein that this is exemplary only. For example, in other embodiments, the line pressure need not be entirely reduced. Instead, in one example, rollers  1106 A may become fixed within terminal segments  1102 F, as described above, when the line pressure is above a predetermined level. Once the line pressure is reduced below that predetermined level, which can be greater than zero pressure, the user may be able to overcome the line pressure and disengage rollers  1106 A from terminal segment  1102 F. The predetermined level may be a pressure that does not cause significant leakage of the fluid from conduit  1200  and/or a level which is determined to pose minimal or no risk of significant bodily injury. 
     The described embodiments are to be considered in all respects only as exemplary and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.