Patent Publication Number: US-2023141263-A1

Title: Breakaway assembly

Description:
This application is a continuation of U.S. patent application Ser. No. 17/005,708 entitled BREAKAWAY ASSEMBLY and filed on Aug. 28, 2020, the entire contents of which are hereby incorporated by reference. 
     The present invention is directed to a breakaway assembly, and more particularly for a breakaway assembly for use in a fluid dispensing system. 
    
    
     BACKGROUND 
     Breakaway connectors or assemblies can be utilized in fluid dispensing systems, such as refueling stations and the like. The breakaway assemblies are designed to provide a break in the fluid system which can be closed when a sufficient, predefined separation force is applied thereto. For example, in a drive-away event, the user of a refueling unit may inadvertently leave the nozzle in the tank of a vehicle or automobile and drive away. Breakaway assemblies are designed to provide a breakaway point at which the hose or system can be separated, and also provide a closing valve to prevent or minimize loss of fuel. However, many current breakaway assemblies have various drawbacks. 
     Single use breakaways typically use shear pins or shear grooves, but such shear elements cannot be fully tested during assembly, which can lead to unpredictable performance. Many existing reconnectable breakaways use using garter springs, canted coil springs, compression springs and deflectable members to provide a releasable connection mechanism. However such releasable connection mechanisms can have relatively high variances in the materials and/or tolerances, and thus lead to unpredictable separation force. 
     Existing breakaways can also have issues accommodating pressure pulses in the dispensed fluid. Since single use breakaways use a rigid member that is designed to shear or break when sufficient force is applied, and such components can undesirably separate when a sufficiently powerful pressure pulse is transmitted. Reconnectable breakaways can also be prone to separation due to force or pressure spikes and/or internal components can be damaged due to the force or pressure spike. 
     Finally, existing breakaways typically have valves that are designed to close after a breakaway event. However, the valves may not close in a sufficiently predictable manner. 
     SUMMARY 
     In one embodiment, the present invention is a breakaway assembly that is reconnectable, provides a relatively consistent separation force, in one case using magnets, in one case which can accommodate force or pressure spikes, and in one case provides an improved closure valve arrangement. More particularly, in one embodiment, the invention is a breakaway assembly including a first connector and a second connector releasably coupleable to the first connector, wherein the assembly is movable between a first configuration in which the first and second connectors are releasably coupled and together define a fluid path through which fluid is flowable, wherein the fluid path includes an at least partially radially extending portion, and a second configuration in which the first and second connectors are not coupled together. The assembly is configured to move from the first configuration to the second configuration when a predetermined separation force is applied to the assembly. One of the first or second connectors has a shaft which defines or includes at least part of the fluid path therein, and the at least partially radially extending portion includes or is defined by an opening in the shaft. The assembly further includes a closure valve positioned in the one of the first or second connectors. The closure valve is configured to be in an open position when the assembly is in the first configuration to allow fluid to flow therethrough, and to move to a closed position blocking the at least partially radially extending portion of the fluid path when the assembly moves to the second configuration to generally block a flow of fluid therethrough. The closure valve includes a slider that is configured to sealingly engage the shaft to seal the fluid path when the assembly is in the closed position. The assembly is configured to be pressure balanced when the assembly is in the second configuration such that internal pressure-induced force is balanced when the assembly is in the second configuration and pressurized fluid is positioned in the fluid path. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a schematic representation of a refueling system utilizing a breakaway assembly; 
         FIG.  1 A  is a detail view of the area indicated in  FIG.  1   ; 
         FIG.  2    is a side cross sectional view of one embodiment of a breakaway assembly, shown in its connected configuration; 
         FIG.  3    is a side cross sectional view of the breakaway assembly of  FIG.  2   , shown in its disconnected configuration; 
         FIG.  4    is front perspective view of the magnet unit of the breakaway assembly of  FIG.  2   , shown partially disassembled; 
         FIG.  5    is a front perspective view of the magnet unit of  FIG.  4   , shown in an assembled condition; 
         FIG.  6    is a cross section taken along line  6 - 6  of  FIG.  5   ; 
         FIG.  7    is a cross section of an alternate configuration of the magnet unit of  FIG.  4   ; 
         FIG.  8    is a cross section of an alternate configuration of the magnet unit of  FIG.  4   ; 
         FIG.  9    is a cross section of an alternate configuration of the magnet unit of  FIG.  4   ; 
         FIG.  10    is a cross section of an alternate configuration of the magnet unit of  FIG.  4   ; 
         FIG.  11    is a cross section of an alternate configuration of the magnet unit of  FIG.  4   ; 
         FIG.  12    is a front perspective view of an alternate embodiment of the magnet unit of  FIGS.  4  and  5   ; 
         FIG.  13    is a side cross sectional view of the breakaway assembly of  FIG.  2   , shown accommodating a force spike; 
         FIG.  13 A  is a detail view of the area indicated in  FIG.  13   ; 
         FIG.  14    is a side cross sectional view of another breakaway assembly; 
         FIG.  15    is a cross-sectional view of the magnet unit of the breakaway assembly of  FIG.  14   , taken along line  15 - 15 ; 
         FIG.  15 A  is a side perspective view of a magnet retainer of the magnet unit of  FIG.  15   ; 
         FIG.  16    is a detail cross section of the area indicated in  FIG.  13 A  showing another embodiment of the breakaway assembly with a magnetic assembly for accommodating a force spike; 
         FIG.  16 A  shows the components of  FIG.  16    in the process of accommodating a force spike; 
         FIG.  17    is a side cross sectional view of another embodiment of a breakaway assembly, shown in its connected configuration; 
         FIG.  18    is a side cross sectional view of the breakaway assembly of  FIG.  17   , with the shuttle moved downstream as a step of disconnection; 
         FIG.  19    is a side cross sectional view of the breakaway assembly of  FIG.  17   , shown in its disconnected configuration; 
         FIG.  20    is a detail cross section of the area indicated in  FIG.  17   , shown accommodating a force spike; 
         FIG.  21    is a side cross sectional view of the breakaway assembly of  FIG.  17   , shown in conjunction with a reconnection tool; and 
         FIG.  22    is a side cross sectional view of the breakaway assembly of  FIG.  21   , shown in its connected configuration. 
     
    
    
     DETAILED DESCRIPTION 
     System Overview 
       FIG.  1    is a schematic representation of a refilling system  10  including a plurality of dispensers  12 . Each dispenser  12  includes a dispenser body  14 , a hose  16  coupled to the dispenser body  14 , and a nozzle  18  positioned at the distal end of the hose  16 . Each hose  16  may be generally flexible and pliable to allow the hose  16  and nozzle  18  to be positioned in a convenient refilling position as desired by the user/operator. 
     Each dispenser  12  is in fluid communication with a fuel/fluid storage tank  20  via a liquid or fluid conduit or path  22  that extends from each dispenser  12  to the storage tank  20 . The storage tank  20  includes or is fluidly coupled to a fuel pump  24  which is configured to draw fluid/fuel out of the storage tank  20  via a pipe  26 . During refilling, as shown by the in-use dispenser  12 ′ of  FIG.  1   , the nozzle  18  is inserted into a fill pipe  28  of a vehicle fuel tank  30 . The fuel pump  24  is then activated to pump fuel from the storage tank  20  to the fluid conduit  22 , hose  16  and nozzle  18  and into the vehicle fuel tank  30  via a fuel or fluid path or fluid conduit  32  of the system  10 . 
     In some cases, the system  10  may also include a vapor path  34  extending from the nozzle  18 , through the hose  16  and a vapor conduit  36  to the ullage space of the tank  20 . For example, as shown in  FIG.  1 A , in one embodiment the vapor path  34  of the hose  16  is received in, and generally coaxial with, an outer fluid path  32  of the hose  16 . The nozzle  18  may include a flexible vapor boot or bellows, sleeve or the like (not shown) of the type well known in the art which is coupled to, and circumferentially extends around, a spout  40  of the nozzle  18 . 
     The bellows is designed to form a seal about the spout  40  when the spout  40  is inserted into the fill pipe  28 . The bellows help to capture vapors and route the vapors into the vapor path  34 , although vapors can also be captured with nozzles  18  lacking a bellows. The system  10  may include a vapor recovery pump  25  which applies a suction force to the vapor path  34  to aid in vapor recovery, although in some cases (e.g. so-called “balance” systems) the vapor recovery pump  25  may be omitted. In addition, in some cases the system  10  may lack the vapor path  34 , in which case the system  10  may lack the vapor conduit  36 , and the hose  16  may lack the vapor path  34  therein. 
     The system  10  disclosed herein can be utilized to store/dispense any of a wide variety of fluids, liquids or fuels, including but not limited to petroleum-based fuels, such as gasoline, diesel, natural gas (including compressed natural gas (CNG)), biofuels, blended fuels, propane or liquefied petroleum gas (LPG), oil or the like, or other fuels or liquids such as hydrogen, ethanol the like, 
     Each dispenser  12  may include a breakaway assembly  42  associated therewith, which can be located at various positions on the dispenser  12 , or along the system  10 . For example, the left-most dispenser  12 ′ of  FIG.  1    utilizes a breakaway assembly  42  at the base end of the hose  16 ; the middle dispenser  12  of  FIG.  1    utilizes a breakaway assembly  42  positioned adjacent to the nozzle  18 ; and the right-most dispenser  12  of  FIG.  1    utilizes a breakaway assembly or assembly  42  at an intermediate position of the hose  16 . However, it should be understood that the breakaway assembly  42  can be positioned at any of a wide variety of positions along the length of the hose  16 , or at other positions in the refueling system  10 . The breakaway assembly  42  may include, and/or be coupled to, a swivel assembly to enable the breakaway assembly  42  to assume various positions and become aligned with any separation forces applied thereto. 
     Breakaway Overview 
       FIGS.  2  and  3    illustrate one embodiment of the breakaway assembly  42 , for use with conventional (typically liquid) fuels such as gasoline, diesel, oil or the like that are pumped under relatively low pressure, such as less than about 50 psi in one case, or less than about 100 psi in another case, or less than about 150 psi in another case, or less than about 300 psi in yet another case. The breakaway assembly  42  includes a first or upstream connector  44  releasably connected to a second or downstream connector  46 . The breakaway assembly  42  and connectors  44 ,  46 , are generally annular in one case, with the fluid path  32  positioned therein, but can have other shapes as desired. The first connector  44  may be connected to an upstream portion of the system  10 /hose  16 , and the second connector  46  may be connected to a downstream portion of the system  10 /hose  16  (it should be understood that terms used in relation to the direction of flow, such as “upstream” and “downstream,” are used herein with respect to the direction of the flow of fluids/fuel to be dispersed (i.e. right-to-left in  FIGS.  2 ,  3 ,  13  and  14   , and left-to-right in  FIGS.  17 - 19   , as opposed to for example the direction of vapor flow, unless specified otherwise). However, if desired this orientation may be reversed such that first connector  44  is connected to a downstream component, and the second connector  46  is connected to an upstream component. Both the first connector  44  and second connector  46  can include threaded surfaces (such as the illustrated internal threaded surfaces or threaded adapters  48 ) for securing the connectors  44 ,  46  to the associated upstream and downstream components. The threaded surfaces  48  could instead take the form of externally threaded surfaces, or various other coupling structures besides threaded surfaces may be used. 
     The first connector  44  may include a generally tubular or annular coupling portion  50 , which can have a variety of shapes in cross section, and which can be removably receivable in a socket or protective cover  52  of the second connector  46 . The second connector  46  further includes a closure valve or poppet valve  54  positioned therein. The poppet valve  54  includes a body portion  56  having a downstream stem  58 , an upstream stem  62 , and seal or sealing portion  64  coupled to the body portion  56 . The downstream stem  58  is slidably received in a guide  66  which is positioned or centered in the second connector  46  by a plurality of radially-extending fins  68 . The poppet valve  54  further includes a spring  74  positioned axially between the guide  66  and the body portion  56 . The body portion  56 /poppet valve  54  is thereby biased, by the spring  74 , to an upstream/closed position in which the sealing portion  64  sealingly engages the poppet valve seat  76  (see  FIG.  3   ). The second connector  46  may include a seal  47  on a radially outer surface of its axially-forwardly extending end to help form a seal with the inner surface of the first connector  44 . 
     The first connector  44  may include a closure valve or poppet valve  80  positioned therein. The poppet valve  80  includes a body portion  82  having a downstream stem  84 , an upstream stem  86 , and seal or sealing portion  88  coupled to the body portion  82 . The upstream stem  86  is slidably received in a guide  90  which is positioned/centered in the first connector  44  by a plurality of radially-extending fins  92 . The poppet valve  80  further includes a spring  94  positioned between the guide  90  and the body portion  82 . The body portion  82 /poppet valve  80  is thereby biased, by the spring  94 , to a downstream/closed position in which the sealing portion  88  sealingly engages the poppet valve seat  96  (see  FIG.  3   ). 
     During normal operation of a dispenser  12 , the first connector  44  and second connector  46  are arranged in their first/locked/connected/engaged state or configuration, as shown in  FIG.  2   , in which the first  44  and second  46  connectors are coupled together and define an open fluid conduit, or fluid path  32  through which fluid may flow, as shown by the arrows of  FIG.  2   . In this configuration, the upstream stem  62  of the poppet valve  54  engages and moves the downstream stem  84  of poppet valve  80  away from its valve seat  96 , and vice versa, such that the springs  74 ,  94  of both poppet valves  54 ,  80  are compressed and both poppet valves  54 ,  80  are opened. When the poppet valves  54 ,  80  are opened the seals  64 ,  88  are spaced away from their associated seats  76 ,  96 , enabling fluid to flow through the fluid path  32 /breakaway assembly  42 /connectors  44 ,  46 . As will be described in greater detail below, a coupling mechanism or coupling system  41  is provided to releasably couple the connectors  44 ,  46  in the axial direction. 
     When sufficient separation forces are applied to the assembly  42  (i.e. forces applied at least partially along the axis of the breakaway assembly  42 /connectors  44 ,  46 ), the coupling mechanism  41  releases/separates and the breakaway assembly  42  moves to its second/separated/disconnected state or configuration as shown in  FIG.  3   . When the connectors  44 ,  46  are moved away from each other, the downstream stem  84  of the poppet valve  80  is pulled away from the upstream stem  62  of poppet valve  54 . The relative movement of the connector(s)  44 ,  46  away from each other enables the poppet valves  54 ,  80  to move to their closed positions, as shown in  FIG.  3    in which the seals  64 ,  88  engage their associated valve seats  76 ,  96 , as biased by their associated springs  74 ,  94 . 
     The assembly  42  may be reusable and may be configured such that the connectors  44 ,  46  are connectable/reconnectable (i.e. movable from the configuration of  FIG.  3    to that of  FIG.  2   ) without requiring any repair or replacement of any components of the assembly  42 . In particular, when the first connector  44  and second connector  46  are connected/reconnected, the downstream stem  84  of the poppet valve  80  engages the upstream stem  62  of the poppet valve  54 . When sufficient axial compression forces are applied to the assembly  42  during the reconnection process, the body portions  56 ,  82  of the poppet valves  54 ,  80  and associated seals  64 ,  88  are moved away from their respective valve seats  76 ,  96  until the valves  54 ,  80  are in the position shown in  FIG.  2   . 
     The illustrated embodiment shows both the first  44  and second  46  connectors having poppet valves  54 ,  80  therein. However, in an alternate embodiment, only one of the connectors  44 ,  46  has a poppet valve. In this case, the other connector  44 ,  46 , lacking a poppet valve, may include a rigid, axially-extending hold-open stand, analogous to the portions  62 / 84 , which extends axially forwardly and can engage the poppet valve (e.g. valve  54 ,  80 ) in the other connector  44 ,  46  and urge the other poppet valve to the open position when the assembly  42  is in its connected configuration. In yet another alternate embodiment, when the assembly  42  is used with dispensing systems utilizing vapor recovery systems, one or both of the connectors  44 ,  46  may include poppet valves in or at least partially defining the vapor path  34  which are opened when the assembly  42  is in the connected configuration, and which automatically close when the assembly  42  moves to the disconnected position. Examples of these arrangements are disclosed in U.S. Pat. No. 8,931,499, the entire contents of which are hereby incorporated by reference herein. 
     Magnetic Coupling/Breakaway 
     The assembly  42  may include the coupling mechanism  41  which releasably couples the connectors  44 ,  46  together to retain the assembly  42  in its coupled position until sufficient axial forces are applied. The coupling mechanism  41  may include a magnet unit  43 , which includes a magnet coupler  102  that receives various magnets  104  therein. The magnet unit  43  is coupled to the first connector  44  in the illustrated embodiment. The coupling mechanism  41  can also include an attraction member  106  (or other member which completes the magnetic circuit) which can be made of a ferrous material or other material that is magnetically attracted or attractable to the magnets  104 /magnet unit  43 . The attraction member  106  is coupled to the second connector  46  in the illustrated embodiment. In the particular illustrated embodiment the magnet unit  43  constitutes or defines the coupling portion  50  of the first connector  44  that is received in the socket/cover  52  of the second connector  46 . If desired, the positioning of the magnet unit  43  and attraction member  106  can be reversed from that shown such that the attraction member  106  is coupled to the first connector  44 , and the magnet unit  43  is coupled to the second connector  46 . 
     In one embodiment the attraction member  106  is generally annular and made of a ferrous material or other magnetizable material, and directly threadably attached to the body of the first connector  44 . The attraction member  106  could instead be made of or include a magnet or magnets configured and arranged to be magnetically attracted to an associated magnet(s)  104  of the magnet unit  43  when properly aligned. Further alternately, rather than being a continuous annular member, the attraction member  106  can instead take the form of various, discrete and spaced apart attraction member units or portions positioned to magnetically interact with the magnet unit  43 . 
     The magnets  104  of the magnet unit  43  can be made of any of a wide variety of materials, including permanently magnetized materials such as rare earth magnets, including neodymium in one case. The magnet coupler  102  and/or attraction member  106  can be made of a magnetized and/or magnetizable material such as ferromagnetic material or metal (iron, cobalt, nickel, manganese, gadolinium, dysprosium or others), paramagnetic materials, diamagnetic materials, ferrimagnet metals, ferromagnetic alloys, sheet steel or cast steel, or in some cases non-magnetized or non-magnetizable material, each of which can if desired be covered with a ferromagnetic coating or plating, such as nickel in one case but could be nearly any ferromagnetic metal or alloy which will not unduly interfere with any potentially desired magnetic field. The magnets  104  and/or magnet coupler  102  and/or attraction member  106  can be plated, coated, encapsulated or unplated. 
     In one case the magnet coupler  102  and/or attraction member  106  can have, or be made of a material having, a saturation point that is greater than about 1.25 Tesla to provide the desired ferromagnetic response. In particular, it may be desired to have the magnet coupler  102 , as energized/magnetized by the magnets  104  received therein, magnetically interact with the attraction member  106  as a unit, rather than have the individual magnets  104  directly magnetically interact with the attraction member  106 . The magnet coupler  102  can thus be configured, sized and shaped to direct the magnet field in a desired and advantageous manner. In particular, by passing the induced magnetic field through the magnet coupler  102 , the magnetic field lines originating with the magnets  104  tend to pass through the radially inner  108  and radially outer  110  annular components or surfaces of the magnet coupler  102  (and not, for example, through the web or end wall  112  at the base of the magnet coupler  102 ), which provides a stronger magnetic force since the web  112  acts as a shunting member. Moreover, since the web  112  acts as a shunting member it may be desired to avoid or minimize the magnetic field lines passing through the web  112 , and thus may be desired to keep the web  112  as thin as possible. 
     The web  112  may have a thickness (e.g. in the axial direction) that allows the greatest amount of magnetic flux field to pass into/through the magnet coupler  102 , which is dependent on a balance of factors, including the strength of the magnetic field, and the permeability and saturation limits of the materials of the magnet coupler  102 . The ratio of the thickness of the web  112 , to the field penetration depth, may between about 5% and about 15% in one case, where the field penetration depth is dependent on the saturation point of the material of the magnet coupler  102 . In a case where the magnetic flux density is between 1.25 T and 2 T, the field penetration depth can be between 0.25″ and 0.625″, and the thickness of the web  112  can range from 0.0125″ to 0.09375″. In one case the web  112  has an axial length of less than about 25% in one case, or less than 10% in another case, or less than 5% in another case, or less than 2.5% in another case of a length of the magnets  104  and/or length of the magnet unit  43 . In some cases it may be desired to eliminate the web  112  entirely for magnetic performance, but doing so could create difficulties in physically retaining the magnets  104  in the desired axial position in the magnet coupler  102 . In some cases the web  112  can be slotted or have other openings to reduce the shunting effect of the web  112 . 
     The attraction member  106  and magnet unit  43  can thus form the coupling mechanism  41  that releasably couples the connectors  44 ,  46  together and tends to retain the assembly  42  in its first/locked/connected/engaged state or configuration, as shown in  FIG.  2   . The coupling mechanism  41  may thus solely or primarily determine the separation force of the breakaway assembly  42 . 
     When an external axial force is applied to the breakaway assembly  42  that is greater than the attractive force of the magnet unit  43  to the attraction member  106 , a separation will occur in the following sequence. The downstream connector  46  will first move away from the upstream connector  44 , along with nearly all associated portions of the downstream connector  46  (e.g. except for the associated poppet valve  54  which may begin to close). Both poppet valves  54 ,  80  may simultaneously start move to their closed position. In one case, after roughly ¼″ of travel of the connectors  44 ,  46  away from each other, both poppet valves  54 ,  80  will be fully moved to their closed positioned. As the separation motion continues, at a greater distance, about 5/16″ of travel in one case, the upstream connector  44  will be fully extracted out of the socket  52  of the downstream connector  46  (shown as nearly fully extracted in  FIG.  3   ). In this state the connectors  44 ,  46  are separated and the poppet valves  80 ,  54  are closed to prevent or limit the leakage of fluid. 
     After the connectors  44 ,  46  are separated, it may then be desired to reconnect the connectors  44 ,  46 . In one case the connectors  44 ,  46 , can be axially aligned and manually pressed together such that the magnet unit  43  fits into the socket  52 . The connectors  44 ,  46  are then pressed together, and the springs  94 ,  74  compressed until the poppet valves  80 ,  54  are open as shown in  FIG.  2   . During a reconnection event, since the attraction member  106  is positioned on or in the downstream connector  46 , the magnet unit  43  will be at some point during insertion be sufficiently attracted to the attraction member  106  such that the magnet unit  43 /assembly  42  may be felt to “snap” into place. In addition, the attraction between the magnet unit  43  and the attraction member  106  may reduce the reconnection force and act as a magnetic assist feature, aiding a user in reconnection. Thus the (manual) force required to connect the first  44  and second  46  connectors can be less than the force required to separate the first  44  and second  46  connectors in a breakaway event, which can provide an easier and more convenient reconnection process. 
     Magnet Coupler Configuration 
     In the embodiment shown in  FIGS.  2 - 6   , the magnet coupler  102  has an upstream portion  102   a  with an annular channel or channel portion  114  formed therein, that is removably attachable to a downstream portion  102   b  with a correspondingly shaped and located channel or channel portion  116 . Each portion  102   a ,  102   b  can have a web or end wall  112  positioned at an axial end of the portion  102   a ,  102   b  and positioned adjacent to the associated channel  114 ,  116 . The upstream  102   a  and downstream  102   b  portions can be separate components or parts that are coupled together at or along a joint  105  that is aligned in a radial plane. One or both channel portions  114 ,  116  can receive the magnets  104  therein. Each magnet coupler portions  102   a ,  102   b  can include a threaded surface  103  thereon, where the threaded surfaces  103  are configured to threadably engage each other to form the generally closed magnet coupler  102  shown in  FIG.  4    (when assembled) and  FIG.  5   . When the magnet unit  43  is fully assembled by joining the upstream  102   a  and downstream  102   b  portions by mechanical, releasable or other means an internal, closed channel  114 ,  116  is formed therein that receives and encapsulates the magnets  104  therein. 
     In the illustrated embodiment and with reference to  FIG.  4   , in one case each magnet  104  is shaped as a rectangular prism and the poles  118 ,  120  of the magnets  104  are oriented perpendicular to the largest face of the magnet  104 . In one case the magnets  104  are arranged with their north poles  118  positioned on (extending perpendicular to) the radially inner faces of the magnets  104 , and their south poles  120  positioned on (extending perpendicular to) the radially outer faces of the magnets  104 . Thus the poles  118 ,  120  of the magnets  104  can be oriented perpendicular to the central axis A ( FIG.  2   ) of the assembly  42 , or non-parallel with axis A, and aligned with a radial line pointing radially inwardly or outwardly. 
     As shown in  FIG.  6   , in one case the channel  114  of the upstream portion  102   a  can be formed in end view as a prism with a number of sides (twelve sides in the illustrated embodiment) that corresponds to the number of magnets  104 , where the number of sides of the channel  114  can be adjusted to match the number of magnets  104  to be used. It is noted that while  FIG.  6    illustrates the channel  114  formed in portion  102   a , the channel  116  in the portion  102   b  can have the same shape and positioning. It is also noted that when the channels  114 ,  116  are not circular, the magnet coupler portions  102   a ,  102   b  may be connected together by means other than threaded surfaces  103 , such as by using press fit, rabbiting, retaining rings or the like. The polygon shape for the channels  114 ,  116  can help to reduce any air gap between the poles/largest face of the magnets  104  and the magnet coupler  102 , thereby increasing magnetic performance. In addition, this configuration enables the use of magnets  104  that are rectangular prisms, as compared to for example curved magnets, which can be more expensive and difficult to manufacture. 
     The polygon of the channels  114 ,  116  can be regular or irregular, and in one case has at least four sides. However, the polygon-shaped channel  114 ,  116  can in some cases be difficult to machine. Thus, if desired channels  114 ,  116  having a circular shape, which is easier to machine, can be used as shown in  FIG.  7   , and used in conjunction with rectangular prism magnets  104 . In this case the magnets  104  can be positioned tangent to the channel  114 ,  116 . Moreover, in this case the magnets  104  and/or channel  114 ,  116  can also be configured such that each magnet  104  has three points of contact (or potential contact) with the channel  114 ,  116 : the center portions of each magnet  104  may be in contact or near contact with the radially-inner wall of the channel  114 ,  116 , and the circumferentially outer portions of each magnet  104  may be in contact or near contact with the radially-outer wall of the channel  114 ,  116 . The three points of contact (or near contact) helps to securely locate each magnet  104  in the channel  114 ,  116 . 
     In order to position the magnets  104  in the channel  114 ,  116  it may not be practical to provide three points of actual contact due to lack of sufficiently precise manufacturing and lack of sufficient tolerances. In this case there may be a relatively small radially-extending outer gap  122  between the circumferentially outer portions of the magnets  104  and the radially-outer wall of the channel  114 ,  116 , and/or between the inner/central surface of the magnets  104  and the radially-inner wall of the channel  114 ,  116 . The gap(s)  122  for a given magnet  104  may have a total cumulative length (in the radial direction) of less than about 0.1″ in one case, or less than about 0.05″ in one case, or less than about 0.03″ in another case, or less than about 1% of the length of the magnet  104  (in a generally circumferential direction). The gap(s)  122  may also be less than about 5% in one case, or less than about 1% in another case, relative to a radius of an outer surface of the portion  102   a / 102   b.    
     Each magnet  104  may also define a somewhat triangular-shaped gap  124  positioned between the circumferentially-outer portions of adjacent magnets  104  and the radially inner surface of the channel  114 ,  116 . The inner gap  124  can be reduced as more magnets  104  are used. The gap(s)  124  for a given magnet  104  can each, or cumulatively, have a length in the radial direction that corresponds to the parameters of the gap  122  outlined above. 
     The magnets  104  can also be positioned in various different arrangements such as that shown in  FIG.  8    wherein the magnets  104 , in end view, are positioned in discrete, spaced apart, generally radially aligned closed channels, in the same or similar manner as shown in the embodiment of  FIGS.  14 ,  15  and  15 A  and described in greater detail below. Alternatively, as shown in  FIGS.  9 - 11    the magnets  104  can be positioned in channels  114 ,  116  that form various angles (defined by the angle between: a) a radially outwardly extending line aligned with the channel  114 ,  116  and b) a radial line, as shown by the labelled angles in  FIGS.  9 - 11   ). Thus the plane defined by the largest faces of the magnets  104  can be oriented perpendicular to a radial line ( FIGS.  6  and  7   , wherein the poles are aligned with a radial line), or parallel to radial line ( FIG.  8   , wherein the poles are oriented perpendicular to a radial line) or positioned at various angles relative to a radial line ( FIGS.  9 - 11   ). 
     Since each magnet  104  can be formed as a rectangular prism, each magnet  104  may have a longest dimension (a length, in one case), that extends or is oriented or aligned axially in the disclosed embodiment. Each magnet  104  may have a second-longest dimension (a width, in one case) that extends or is oriented or aligned radially (e.g. extends along a radial line) as in the embodiment of  FIG.  8   ; or that extends or is oriented or aligned generally circumferentially as in the embodiments of  FIGS.  6  and  7   . Each magnet  104  may have a third-longest dimension (thickness) that extends or is oriented or aligned radially (e.g. extends along a radial line) as in the embodiment of  FIGS.  6  and  7   . In this configuration the magnets  104  can also be considered to be circumferentially aligned. 
     In the embodiment of  FIG.  11    the face of the magnets  104  with the north poles  118  can be arranged to face radially inward, toward the central axis A of the assembly  42 , which controls how the magnetic circuit is completed by forcing the magnetic field through the attraction member  106 . This arrangement of inwardly-facing north poles  118  may be utilized when the magnets  104  are at an angle, relative to a radial line (on the radially outer side of the magnet  104  in one case), of equal to or greater than 45 degrees as shown in  FIG.  11   , and also  FIGS.  6  and  7   . 
     In arrangements when the magnets  104  are arranged at angles equal to or less than 45 degrees (e.g.  FIGS.  8 - 10   ) the polarity of the magnets  104 , or the inwardly-facing surfaces of the magnets  104 , can alternate between the north poles  118  and south poles  120 . In these cases the poles  118 ,  120  of the magnets  104  can alternate such that a north pole  118  of each magnet  104  faces the north pole  118  of an adjacent magnet  104 . In addition, in these configurations an (exactly) even number of magnets  104  may be utilized to ensure the alternating pattern is maintained about the entire circumference of the magnet unit  43 . This alternating arrangement of magnets  104  (e.g. when arranged at angles of equal to or less than 45 degrees) maximizes the magnetic flux field to generate the highest level of available magnetic attractive force by physically isolating the opposite poles  118 ,  120  of adjacent magnets  104  to avoid a magnetic short-circuit between adjacent magnets  104 . 
     The arrangement shown in  FIGS.  8 - 10    (e.g. magnets  104  arranged at angles of equal to or less than 45 degrees) can also reduce the adverse effects from the repulsive forces between adjacent magnets  104 . Such a repulsive force will occur when the magnetic field is flowing from north  118  to south poles  120  on a magnet  104 , and the magnetic field from an adjacent magnet  104  is flowing in the same direction. These magnetic interactions can thereby be accommodated by the alternating pole arrangement to avoid a reduction in the net magnetic attractive force, which as noted above defines or primarily determines the separation force between the magnet unit  43  and the attraction member  106 . 
     If the magnets  104  are arranged at angles of equal to greater than about 45 degrees (for example  FIGS.  6  and  7    (90 degrees) and  FIG.  11    (60 degrees)), the number of magnets  104  can be even or odd, and the magnetic poles  118 ,  120  may not need to be alternated due to dissipated magnetic forces. In the embodiment of  FIG.  11    the strength of the magnets  104  may need to be relatively low since the adjacent magnets  104  may be more prone to a “short circuit” since the north poles  118  are not as physically isolated from the south poles  120  of an adjacent magnet  104 . In addition, the adjacent magnets  104  may experience greater repulsive forces since the poles  118 / 120  on one magnet  104  are not as physically isolated from the poles  118 / 120  on an adjacent magnet  104 . Thus in one case the magnets  104  are positioned at an angle other than perpendicular relative to a radial line in axial end view. However, in some cases the embodiment of  FIG.  11   , or other similar arrangements which do not provide optimized magnetic performance, may be desired when the magnetic force is desired to be somewhat lessened to adjust and fine tune the separation force as desired. In addition, it should be noted that other magnet arrangements are possible, some of which are described in greater detail below. 
     In some cases magnet  104  which can be arcuate, and curve around the center A, in some cases matching the curvature of the curved channel  114 ,  116 . However in this case, because an arcuate magnet  104  is used, the inner surface defined by the inner diameter of the arced magnet  104  will have a smaller surface area than the outer surface defined by the outer diameter of the arced magnet. The thicker the magnet  104 , the larger the difference in surface area. 
     As is well known, magnetic flux is the strength of the magnetic force times the area around the pole. When arcuate magnets  104  are used, the magnetic flux on the inner surface of the arcuate magnets  104  is greater than the magnetic flux on the outer surface, since the surface area of the inner surface is smaller than the surface area of the outer surface. It is known that the number of magnetic force lines (magnetic field) from north to south must be the same for each magnet  104 . With the surface area of the inner surface being smaller than that of the outer surface for arcuate magnets  104 , it follows that the flux density on the inner surface will be higher than that of the outer surface. The higher flux density results in a concentrated load on the inner surface of the arcuate magnets  104  that is higher than the load on the outer surface. Thus the use of arcuate magnets  104  provides a net total resultant magnetic force that is lower than what is achievable under an optimized design since the flux field entering the attraction member  106  has a smaller surface area than what is needed to effectively disperse and distribute the magnetic flux field. This results in saturation of the portion of the attraction member  106 , which causes underutilization of the total available magnetic field. It has been found that the largest impact on magnet performance is the surface area of the face of the magnet  104  that is normal to the pole of the magnet  104 . 
     In order to provide a balanced magnetic flux field, it may be desired for the inner annulus  108  of the magnet unit  43  to have an equal cross-sectional area, and/or equal volume, as the outer annulus  110 . However, the inner annulus  108  can have a smaller diameter than that of the outer annulus  110 . Thus as shown for example in  FIGS.  2 ,  3  and  7   , the inner annulus  108  of the magnet unit  43  can be thicker, in the radial direction, than the outer annulus  110 , to provide an equal cross-sectional area and/or volume such that magnetic flux in the inner  108  and outer  110  annuli are equal. 
     In some existing designs, the flux field around the ends of one magnet  104  may be in the same direction as those of an adjacent magnet  104 . These aligned flux forces produces a repelling force and can cause the magnets  104  to eject from the magnet unit  43 , which can in turn cause the magnets  104  to be damaged or lost. The ejection force can also make assembly and repair of the magnet unit  43  difficult, and can require special processes and tools. Additionally, in some existing designs, as the magnets  104  are installed, each magnets  104  is biased to shift away from the adjacent magnet  104  due to the repelling magnetic fields. Thus, in this case the last few magnets  104  to be installed may require use of a special tool to reach into the magnet coupler  102 , and push the aside the existing magnets  104  while installing the last few magnets  104 . 
     The axial length of the channel  114 ,  116  (and/or the axial length of each magnet  104 ) can vary depending on the magnetic flux field desired to be generated at the end of the magnet coupler  102 . The channel  114 ,  116  may have an axial length that is about equal to the axial length of the magnets  104  or slightly greater (within about 0.5% in one case, or about 1% in another case, or within about 5% in another case) such that the channel  114 ,  116  closely axially receives the magnets  104  therein. In addition, the axial position of the channel  114 ,  116  can be adjusted as desired. For example in the embodiment of  FIGS.  4  and  5    the upstream portion  102   a  of the magnet coupler  102 , and its channel portion  114 , can have the same axial length as the downstream portion  102   b  and its channel portion  116 . In this case the channels  114 ,  116  and magnets  104  are axially centered in the magnet coupler  102 . In this scenario the magnetic force on each axial side of the magnet coupler  102  will be the same (assuming other conditions that can effect magnetic force are identical; for example, assuming the upstream  102   a  and downstream  102   b  portions are made of the same material, that their webs  112  have the same thickness, etc.). 
     However if desired the magnet coupler  102 /channels  114 ,  116  can be asymmetrical as shown in  FIG.  12    such that one of the upstream  102   a  or downstream  102   b  portions and/or their channels  114 ,  116  are longer than the other. In this case more of the length of the magnets  104  are received in one of the upstream  102   a  or downstream  102   b  portions. For example, in one case one of the upstream  102   a  or downstream  102   b  portions can have up to ⅞th of the axial length of the combined length of the channels  114 ,  116  and/or up to ⅞th of the axial length of the magnets  104  therein, and the other one of the upstream  102   a  or downstream  102   b  portions can have the remaining (as little as ⅛th, in the described embodiment) of the length of the combined channels  114 ,  116  or magnets  104  therein. The upstream  102   a  or downstream  102   b  portion having the smaller portion of the magnets  104 /channels  114 ,  116  will have the weaker magnetic flux field compared to the other having the larger portion of the magnets  104 /channels  114 ,  116 . 
     The magnetic force on each axial side of the magnet coupler  102  can also be varied depending upon the method/mechanism used to join the upstream  102   a  and downstream  102   b  portions of the magnet unit  43 . In one case the upstream  102   a  and downstream  102   b  portions are welded at the joint  105  to form a welded joint therebetween, although care should be taken that the heat from the welding process does not damage the magnets  104 . In another case the upstream  102   a  and downstream  102   b  portions each have threaded surfaces  103  as noted above and are thus joined at the joint  105  by a threaded connection, but could also be joined by a variety of other mechanisms/methods, such as press fit, rabbiting, retaining rings or the like. 
     The joint  105  in the magnet coupler  102  can cause a flux field leakage, which can vary depending upon the nature of the joint  105 . For example, the magnetic flux field of the magnet coupler  102  can behave similar to fluids that want to travel the path of least resistance. The point of flux field leakage at the joint  105  of the magnet coupler  102  creates an area of resistance, which aids in the division of the magnet field in the magnet coupler  102 . Thus, differing types of joints  105  will permit or block magnetic fields to pass therethrough by differing amounts. 
     For example, certain joints  105  may present a high flux field impedance and block magnetic fields, and thus tend to magnetically isolate the upstream  102   a  and downstream  102   b  portions, which can provide greater control over certain performance parameters. Other joints may have a relatively low flux field impedance to allow/transmit magnetic fields and thus tend to magnetically couple the upstream  102   a  and downstream  102   b  portions, which can provide greater magnetic coupling strength and separation force. If desired a gasket or other component can be positioned in, at or adjacent to the joint  105  to provide a more predictable control of the flux field impedance at the joint  105 . The use of a gasket or component may be more practical when the upstream  102   a  and/or downstream  102   b  portions are made from a paramagnetic or diamagnetic material. The configuration and assembly of the magnet coupler  102  can thus be varied to adjust the force generated at each end thereof to adjust the breakaway features and other magnetic performance of the breakaway assembly  42 . 
     In addition, the materials of the upstream  102   a  and/or downstream  102   b  portions of the magnet coupler  102  can be varied to adjust the magnetic field. For example, the upstream  102   a  and downstream  102   b  portions can be made of various and different ferromagnetic metals or alloys that have differing saturation points. The upstream  102   a  or downstream  102   b  portion that is made of material having a lower saturation point will generate a lower magnetic force. If only one side of the magnet coupler  102  is desired to generate a magnetic force, then one of the portions  102   a ,  102   b  can be made from a ferromagnetic material and the other portion can be made of a paramagnetic or diamagnetic material, such as 300 series stainless steel or 6000 grade of aluminum, and focus the magnetic flux at one end of the magnet coupler  102 . 
     Magnets  104  can often be brittle and therefore it may be desired to position such magnets  104  to avoid receiving direct impacts, or dissipating loads. The magnet unit  43  disclosed herein protects the magnets  104  when they are housed in the closed channels  114 ,  116  of the magnet coupler  102 , and the magnets  104  are protected from direct impact. The closed channels  114 ,  116  allows the end surfaces of the magnets  104  to be recessed such that the attraction member  106  does not physically engage or contact the magnets  104 , but instead engages or contacts the magnet coupler  102 . In addition, the efficient design and layout of the magnet unit  43  maximizes the use of the magnetic flux field and enables the magnet unit  43  to have a relatively small diameter, enabling the breakaway assembly  42  to have a smaller profile. 
     Another concern with magnets  104  is that they can be subject to corrosion. In order to address this issue magnets  104  are often coated or plated with various ferromagnetic metals, plastics or other materials. However, if these coatings are damaged the magnets  104  will be prone to corrosion. Thus care must be taken during assembly and storage of the breakaway assembly  42  to ensure the coating or plating of the magnets  104  is not damaged. The magnet coupler  102  helps to protect the magnets  104  from corrosion by protecting them during the installation process and during use. The design provides a magnet unit  43  with fully encapsulated magnets  104  that are sealed in an airtight and/or water-tight manner as a single sub-assembly that provides ease of handling and assembly, and provides protection to the encapsulated magnets  104 . 
     Another issue that can arise is that magnets  104  may attract metal particles and other items that are attracted to a magnetic field. When such items or particles are positioned on the magnet  104  and/or attraction member  106 , such items or particles can be trapped and impacted when the attraction member  106  and magnet unit  43  engage each other, thereby providing a pressure point that can damage or crack the attraction member  106  or magnet unit  43 . However, in the current design the magnets  104  are positioned in the closed channels  114 ,  116 . Thus the magnets  104  are protected, and the end face of the magnet unit  43 , which can be made of a more rugged material, can bear the brunt of such impacts. In some cases, the radially outer surface of the magnet coupler  102  can be clad in aluminum or some other paramagnetic material to avoid collecting metal from the ambient environment onto the magnet coupler  102 . 
     Some existing designs allow for direct exposure of the magnets to the atmospheric elements, which can lead to damage and/or corrosion. In addition some existing designs have inefficiencies in their magnetic design in that certain portions of the magnetic field must pass through significant areas of air and do not contribute to the magnetic force. In addition some designs distribute the magnetic flux field through an unduly large surface area due to the pattern of the magnets, decreasing the effective strength of the magnetic field. In contrast, in the design disclosed herein the magnets  104  can be fully encapsulated in the magnet coupler  102 , and thus the magnet coupler  102  protects the magnets  104  from any corrosive material or debris. In addition, more magnetically efficient design is utilized. 
       FIGS.  14 ,  15  and  15 A  illustrate one particular embodiment wherein the magnet coupler  102  has a plurality of radially-aligned channels  116 , each of which closely receives a magnet  104  therein. In this case the magnets  104  are generally aligned along a radial line of the breakaway assembly  42 . The magnets  104  can be arranged such that the poles  118 ,  120  are in alternating directions as in the layout of  FIG.  8   . In addition in the case shown in  FIG.  15    there can be twelve channels  116 /magnets  104  that are spaced apart on center by 30 degrees. Each magnet  104  (and corresponding channels  114 ,  116 ) can have a thickness (extending, in the embodiment of  FIG.  15   , generally in the circumferential direction) of between about 0.025 inches 0.3 inches, and more particularly between about 0.1 and about 0.2 inches in another case; a height (extending in the axial direction) of between about 0.2 inches and about 1 inch, and more particularly between about 0.3 and about 0.4 inches in another case; and a length (extending in the radial direction) of between about 0.25 inches and about 2 inches, and more particularly between about 0.5 and about 1.25 inches in another case. The length and height dimensions described above may be reversed if desires. These dimensions of the magnets  104  and channels  114 ,  116  can also apply to the other embodiments described herein, regardless of orientation. 
     In the embodiment of  FIGS.  14 ,  15  and  15 A , the magnet unit  43  may include a magnet retainer  117 , as best shown in  FIG.  15 A , can be used to secure the magnets  104  in the desired position and orientation. In particular the magnet retainer  117  can include a base ring  119  (which can be analogous to and/or define the web  112 ) and a plurality of generally wedge-shaped spacers  121  coupled to and extending axially away from the ring  119 . The spacers  121  define the generally rectangular prism-shaped channels  116  in which the magnets  104  are received. The magnet unit  43  may include a retaining ring  123  ( FIG.  14   ) received in a corresponding recess downstream of the magnet retainer  117  to keep the magnet retainer  117  and magnets  104  in place. 
     In this embodiment the magnet retainer  117  can be made of the same materials, such as ferromagnetic materials, as the attraction member  106  outlined above, and in one case is made of a magnetizable material. In this case the base ring  119  of the magnet retainer  117  can act as a shunting member, analogous to the web or end wall  112  of the embodiment of  FIGS.  2 - 4   , and the spacers  121  can become magnetized by the adjacent magnets  104 . Although the magnet retainer  117  is shown in conjunction with the embodiment of  FIGS.  14  and  15   , it should be understood that the magnet retainer  117  can be used in other configurations, in place of the magnet coupler  102  if desired. 
     As outlined above the coupling mechanism  41 , including the magnet unit  43  and the attraction member  106 , provide the sole or primary separation force to the breakaway assembly  42 . Starting in the coupled position, as shown in  FIG.  2   , the connectors  44 ,  46  are held together by the attractive force between the magnet unit  43  and the attraction member  106 . This attractive force can be at a minimum of 100 lbs. as per the currently applicable U.S. standards/regulations, but can be set at various other levels as desired. Thus use of magnets, along with the various adjustment factors described above, helps to ensure that the separation force of the breakaway assembly  42  is reliable and predictable, with relatively small variances between differing assemblies  42 . In one case the force required to separate the first  44  and second  46  connectors is in one case at least about 50 lbs., or in another case at least about 80 lbs. or in another case at least about 100 lbs., or in another case at least about 150 lbs., or in another case between about 80 lbs. and about 150 lbs., or at least about 300 lbs. in yet another case, or less than about 500 lbs. in one case, or less than about 300 lbs. in yet another case. 
     When it is desired to reconnect the breakaway assembly  42 , the connectors  44 ,  46  can be pressed together in the axial direction, with the stems  84 ,  62  engaging each other and then opening the associated poppet valves  80 ,  54 . When sufficient force is applied the magnet unit  43  is positioned sufficiently close to the attraction member  106  that the attractive force between those components overcomes the repulsive force applied by the springs  94 ,  74 , and the breakaway assembly  42  is retained in the open position shown in  FIG.  2   . 
     Force Spike Accommodation—Spring 
     The fluid in the fluid path  32  can sometimes experience pressure spikes, pressure shocks or line shocks due to uneven operation of the pump  24 , pressure imposed by operation of the user, or by other forces which may be relatively short in duration and tend to cause undesired separation (collectively termed a force spike herein). For example, in conventional fuel systems force spikes can be caused by a shut-off valve in the nozzle  18  closing the fluid path  32 , while the pump  24  continues to operate for short period of time. Force spikes can also be caused by the user jerking on the hose  16 , or from other sources. In many pressure spikes situations, the pressure spike has relatively low energy and may dissipate as it travels through the fluid path, since the fluid may be considered to be incompressible and have a relatively high energy transfer rate. However in this case the pressure spike may be present over a relatively long time period. 
     In some existing systems the force spike can apply a force to the poppet valve  54  of the downstream connector  46  or other components of the downstream connector  46 . In existing single use breakaways, the connecting member that connects the upstream  44  and downstream  46  connectors can be relatively rigid and can shear or break when a sufficient force spike force is applied, causing an undesired separation. Some reconnectable breakaways are better at handling impulse loads generated from, for example, a user jerking on the hose  16 , but a sufficiently high force by user force can still cause separation. Reconnectable breakaways that use compression or canted coil springs may lack sufficient response time; e.g. may not be able to transmit the load through the coils in sufficient time, which can lead to damage to the compression or canted coil spring. 
     The breakaway assembly  42  illustrated in for example  FIGS.  2  and  13    is configured to accommodate force spikes without causing damage to the components and without undue undesired separation. In particular, upstream connector  44  can include an inner member  129  (e.g. defined in one case by portions of the upstream connector  44  other than the magnet unit  43 ) that has a limited range of axial movement or “float” relative to the magnet unit  43  to allow the assembly  42  to accommodate some force spikes without causing undesired separation events. The inner member  129  can be an annular component that extends entirely circumferentially around the fluid path  32 . The magnet unit  43  can thus be considered to be movably mounted within the upstream connector  44 , which enables the assembly  42  to accommodate force spikes in the system without causing separation. 
     In particular, the magnet unit  43 /magnet coupler  102  can have a generally annular skirt  126 , which can be part of or integral with the body of the magnet coupler  102 . The skirt  126  is positioned upstream of the magnets  104 , defining a shoulder  128  and an annular recess  130  positioned upstream of the shoulder  128 . An annular retaining ring  132  is positioned in the recess  130 . The magnet unit  43  further includes a retaining washer  134  positioned adjacent to, and axially downstream from, the retaining ring  132 . 
     The inner member  129  has a lip  136  positioned adjacent to, and axially spaced apart from, the retaining washer  134  when the assembly  42  is in the position shown in  FIG.  2   . A first gap  137  is positioned between the lip  136  and the retaining washer  134  during normal operating conditions. A biasing element or resilient component  138  is positioned in a recess of the inner member  129  and can be in compression and engaging both the inner member  129  and the retaining washer  134 , and can include or take the form of a wire wave spring or other spring or resilient member having a predetermined preload. The resilient component  138  biases the inner member  129  to its rest or axial inner position, shown in  FIG.  1   , and can be fluidly isolated from the fluid path  32 . 
     When a pressure spike propagates through the fluid path  32  and/or an impulse load is applied (e.g. by a user) the applied force can cause the inner member  129  and the poppet valve  80  of the upstream connector  44  (carried therewith) to move axially away from the magnet unit  43  and upstream connector  44 . As shown in  FIGS.  13  and  13 A  in one case the relative movement can appear as the inner member  129  and poppet valve  80  moving upstream, as compared to  FIG.  2   , to an actuated or axial outer position. The inner member  129  can move upstream in a relative direction until the lip  136  of the inner member  129  engages the retaining washer  134 , thereby eliminating the first gap  137  of  FIG.  2   , while introducing a second gap  140  as shown in  FIGS.  13  and  13 A  between the shoulder  128  and the downstream face of the inner member  129 . The magnet unit  43  and the attraction member  106  remain magnetically coupled during such force-spike induced movement, and the full stroke of the force-spike accommodating movement is defined by the first gap  137  of  FIG.  2   , which gap  137  is eliminated in  FIG.  13    during full movement of the inner member  129 . Of course, the inner member  129  does not necessarily need to move a full stroke to accommodate force spikes, and the gap  137  will in such cases be reduced/narrowed but not necessarily eliminated. In the manner the upstream connector  44  can have a gap introduced therein to accommodate force spikes, while the upstream  44  and downstream  46  connectors remain coupled. 
     If the force spike overcomes the resistance of the resilient component  138 , then the inner member  129 /assembly  42  will shift axially out, up to a fixed distance, to its force-spike accommodating position shown in  FIG.  13   . The associated poppet valve  80  remains open and does not shift to its closed position, even when the inner member  129  is in its force-spike accommodating position. The inner member  129  can move to its force-accommodating position, while the remaining portion of the connector  44  and/or the other connector  46  remain relatively fixed. Since the spike forces are typically a quick pulse, once the inner member  129  shifts to the pressure-spike or force-spike accommodating position and the force spike has sufficiently diminished, the resilient component  138  will quickly urge the assembly  42  back to its position shown in  FIG.  2   , wherein the downstream face of the inner member  129  engages and is pressed against the shoulder  128  of the magnet unit  43 . It should be noted that, when in the force-spike accommodating position shown in  FIG.  13   , a sufficient separation force, applied either externally or by a sufficiently high pressure spike or combinations thereof, will still cause the magnet unit  43 /upstream connector  44  to separate from the attraction member  106 /downstream connector  46  in a separation event as described above. 
     The assembly  42  can accommodate force spikes that propagate in both the upstream direction and the downstream direction. In particular, both such force spikes can cause the same relative movement of the assembly from its rest position of  FIG.  2   , as shown in  FIGS.  13  and  13 A . Thus the resilient component  138  can accommodate and absorb the pressure or spike force in either direction. In addition, when a user jerks on the hose  16 , applying a direct physical force that tends to want to separate the assembly  42 , the resilient component  138  can help to absorb such forces and reduce breakaway events. 
     The resilient component  138  will have a predetermined preload force and compression point load. The resilient component  138  and maximum size of the gap  140  will both limit the stroke of the inner member  129  to a predetermined distance to ensure that the seal  47  on the upstream outer circumferential end of the downstream connector  46  is not pulled out of the bore, or out of contact with, of the inner surface of the upstream connector  44  when the assembly  42  is in its force-spike accommodating position. Thus the maximum stroke distance (e.g. axial dimension of the gap  137  and/or gap  140 , possibly shortened by the compressed length of the resilient component  138 ) may be relatively short, such as less than about 5/16″ in one case, or less than about ¼″ in another case, or less than about ⅛″ in another case, or less than or equal to about 1/16″ in another case, and greater than about 1/32″ in yet another case. 
     The force required to cause the assembly  42  to move to its force-spike accommodating position may be set to a lower value than the separation force. For example, if the separation force is set to 250 lbs., then the force required to cause the assembly  42  to move to its force-spike accommodating position can be set at a value less than 250 lbs., for example about 175 lbs. in one case. The assembly  42  may be able to accommodate various levels of force spikes, that are less than the separation force, such at least about 40 lbs. in one case, or at least about 60 lbs. in another case, or at least about 80 lbs. in yet another case, or greater than about 25% of the separation force in one case, or greater than about 50% of the separation force in another case, or less than the separation force in one case, or less than about 90% of the separation force in yet another case. The force required to induce force-spike accommodation should be high enough to accommodate meaningful force spikes, but not so high as to risk being ineffective and effectively overridden by a breakaway event, and not so low as to enable frequent force-spike accommodation which can cause fatigue of the various components that accommodate force spikes. 
     In such a force spike event, the energy of the force spike is absorbed by the resilient component  138 . This accommodation of force spikes reduces unintended separations and improves the fuel dispensing experience. In addition, allowing the inner member  129  to move/float relative to the remainder of the upstream connector  44  isolates the joint  105  of the magnet coupler  102  from fluid spike forces. Instead of applying forces to the joint  105 , the spike forces are applied to annular areas, such as the retainer washer  134 , retaining ring  132 , and recess  130  of the assembly  42 , which can be designed and configured to accommodate applied loads. 
     In addition or in the alternative, instead of having the magnet unit  43  move or “float” to accommodate force spikes, the attraction member  106  can instead be configured to “float” in the downstream connector  46  such that the downstream connector  46  can accommodate force spikes in either direction. In this embodiment, the resilient component  138  (and retaining ring  132  and retaining washer  134 , if desired) are positioned adjacent to the attraction member  106  (e.g. in gap  113  in one case) in manners which are apparent to a person of ordinary skill in the art as taught by the illustrated embodiments in  FIGS.  2  and  13   . In this case, when there is a force spike in the fluid path  32 , the attraction member  106  may move slightly relatively axially, such as downstream, and the associated resilient component  138  is compressed, absorbing the force of the force spike. Once the force spike is dissipated, the attraction member  106  returns to its original position as biased by the spring/resilient member  138 . 
     As outlined above the magnet unit  43  and/or attraction member  106  can use springs or other energy-absorbing devices to accommodate force spikes in the system. In the case where both the magnet unit  43  and attraction member  106  are configured to accommodate force spikes, the force-spike accommodation system can be arranged to accommodate force spikes in a staged manner. For example, the resilient components  138  can have different spring constants or otherwise be arranged to be activated at different levels of force. In this case one of the force-spike accommodation systems can be activated at a lower pressure or force, and the other one of the force-spike accommodation systems can be activated at a higher pressure or force. In one case the higher force-spike accommodation system can be configured to be activated just as the lower force-spike accommodation system reaches its limit; that is in one case as or just before the gap  137  is eliminated. Such a “double floating” system can thereby bracket spike forces and accommodate them in a more efficient manner, and provide the ability the accommodate more powerful force spikes. 
     It should be further understood that the force spike accommodation system, while shown herein in conjunction with a magnetic coupling system  41 , is not necessarily limited to use with such a magnetic coupling system  41 . Instead the force spike accommodation system and features can be used with nearly any system or component for coupling the first  44  and second  46  connectors, including mechanical coupling systems. 
     Force Spike Accommodation—Magnetic 
     In a further alternative embodiment for accommodating force spikes, rather than using the resilient component  138 , as shown, in one case, in  FIG.  16    a magnetizable material  142  can be coupled (e.g. by a schematically-shown threaded joint  144  in one case, but various other coupling mechanisms can be used) to the inner member  129  of the upstream connector  44 , and the magnets  104  can act as a biasing element to aid in accommodating force spikes. The magnetizable material  142  is positioned adjacent to, but not directly coupled to, the shoulder  128  of the magnet unit  43 /magnetic coupler  102 . The magnetizable material  142  can be for example a ferromagnetic alloy member having a saturation point greater than 1.25 Tesla. The magnetizable material  142  can be magnetically attracted to the magnets  104 /magnet unit  43  (with a force lower than the separation force) to allow floating of the magnet unit  43  to accommodate line shock or pressure shock as described above. When a line shock, impulse load or force spike of sufficient force is experienced in the embodiment of  FIG.  16   , the inner member  129  will move relatively upstream (and/or the connector  46  will move relatively downstream), narrowing or closing the gap  137 , while another gap  140  ( FIG.  16 A ) opens between the magnetizable material  142  and the shoulder  128 . 
     When a magnetic force is used to control and accommodate force spikes as per the embodiment of  FIG.  16    for example, one end (e.g. the upstream end) of the magnet unit  43  may be desired to have a lower magnetic force than the other end (e.g. the downstream end) to ensure the force required to cause the assembly  42  to move the assembly  42  to its force-spike accommodating position ( FIG.  16 A ) is lower than the separation force. This can be accomplished in some of the manners outlined above, such as the having the downstream portion  102   b  of the magnetic coupler  102  being made of a material having a higher saturation point then the upstream portion  102   a , thus increasing its efficiency and separation force, or by use of a gasket at the joint  105 , by varying position of the magnets  104  in the magnet coupler  102 , by increasing the thickness of the web, etc. In one case the one of the portions  102   a / 102   b  (the downstream portion  102   b  in one case) of the magnetic coupler  102  can be made of a material having a saturation point of greater than 1.25 Tesla, and the other portion  102   a / 102   b  (the upstream portion  102   a ) can be made of a material having a saturation point of less than 1.25 Tesla, or be made of a paramagnetic or diamagnetic alloy or material. In the case where a spring or other resilient component  138  is used to accommodate force or pressure spikes, the upstream portion  102   a  of the magnetic coupler  102  can be made of a paramagnetic or diamagnetic material, since a magnetic field may not be needed on the upstream side of the magnet coupler  102 . 
     Another way to provide a reduced magnetic force on the upstream end of the magnet unit  43 /magnetic coupler  102  would be to simply increase the thickness of the web  146  (e.g. the axially extending thickness at the upstream end) of the upstream portion  102   a , which shunts the magnetic flux to reduce the magnetic force to the desired level. However it has been found that if the web thickness  146  is made too great (greater than about ¼″ in one case) the attraction force may be lowered too much, and thus may not be practical. On the other hand, if the web thickness  146  is too small (less than about 1/64″ in one case) the strength/integrity of the magnet unit  43  may be compromised. Another way to provide a reduced magnetic force on the upstream end of the magnet unit  43  would be to reduce the diameter of the magnet unit  43 , which reduces magnetic efficiency. 
     It should also be understood that the magnetic-based system for dissipating force spikes ( FIGS.  16  and  16 A ) can be used in combination with the spring-based system for dissipating force spikes ( FIGS.  1 ,  12 ,  13  and  15   ) to provide two separate systems, usable together, for accommodating force spikes, acting either on the same components, or on different components to provide staged force spike accommodation as outlined above. It should also be noted that the magnetic pressure dissipation system can also be used in the downstream connector  46 , with corresponding structure to that described above being provided and adjusted as needed. 
     Thus, it can be seen that when the magnet unit  43  is used to accommodate force spikes, the magnet unit  43  serves a dual purpose in controlling the separation force and also controlling the force-spike accommodation force. Accordingly the magnet unit  43  provides a usable magnetic field on both axial ends thereof, where the relative strength of the magnetic field on each end can be controlled as desired. Alternatively the magnet unit  43  may provide a usable magnetic field on only one end thereof 
     Relatively Higher-Pressurized Safety Breakaway 
     The breakaway assembly  42  described above is generally designed for use with convention fuels, such as gasoline, diesel, etc. that are not stored and/or delivered under significant pressures. However the magnetic breakaway design and/or similar or analogous structures can also be used in systems that store and deliver fuel or fluid under relatively high pressure, such as CNG, hydrogen, LPG or the like. In these cases the fuel can be stored and dispensed under pressure (in one case in the range of between about 70 psi and about 10,000 psi, and in another case between about 2,900 psi and about 3,600 psi, or at least about 70 psi in one case, of at least about 150 psi in one case, or at least about 2,000 psi in another case, or in another case at least about 2,900 psi, or less than about 3,600 psi in one case, or less than about 10,000 psi in another case). 
     The breakaway assembly  42 ′ shown in  FIGS.  17 - 22    is somewhat analogous to those shown in  FIGS.  2 - 16   , with the same reference numbers (either with or without a “prime” indicator and/or a letter indicator in certain cases) used for the same or analogous components, although the flow direction in the drawings of  FIGS.  17 - 22    is opposite to that of the  FIGS.  2 - 16    embodiment. Thus for example the breakaway assembly  42 ′ of  FIGS.  17 - 22    includes the first or upstream connector  44 ′ and the second or downstream connector  46 ′, and fluid to be dispensed flows in a left-to-right direction. The first connector  44 ′ includes a connection structure  147  having a series of generally axially-extending, circumferentially spaced flanges or jaws  148  that can releasably engage a circumferentially extending recess/ramp  150  on the second connector  46 ′, as will be described in greater detail below. The second connector  46 ′ has a neck portion  154  which carries the recess  150  on a radially outer surface thereof, and a fixed shaft member  153  is positioned in the second connector  46 ′. The shaft member  153  has an inner cavity  155  thereon and facing upstream. A poppet valve  80 ′ is positioned in the second connector  46 ′. A valve  151 , such as a curtain valve having curtain valve member, shuttle valve, closure valve or slider  152  is movably positioned in the first connector  44 ′, and movable between an upstream/open position, shown in  FIG.  17   , and a downstream/closed position, shown in  FIGS.  18  and  19   . 
     The first connector  44 ′ includes a center shaft or tubular structure  158  about which the slider  152  is movably/slidably mounted. The slider  152  includes an annular sealing structure  156  that closely fits about the center shaft  158 . The center shaft  158  can be hollow, having a central cavity  160  therein and a plurality of radially-extending openings  162  (or at least partially radially-extending openings  162  which can extend primarily radially, or form an average angle of greater than 45 degrees relative to a central axis in one case, or greater than 65 degrees in another case, or strictly radially extending in yet another case) which form part of the fluid path  32 , positioned adjacent to a downstream end thereof, that are in fluid communication with the cavity  160 . The first connector  44 ′ has a pair of seals  164 ,  166  positioned on the center shaft  158 . The upstream seal  164  is positioned upstream of the openings  162 , and the downstream seal  166  is positioned downstream of the openings  162 . 
     When the assembly  42 ′ is in its connected configuration, as shown in  FIG.  17   , the downstream end of the center shaft  158  is received in the inner cavity  155  of the shaft member  153 . In this position the downstream seal  166  of the first connector  44 ′ engages the radially inner surface of the shaft member  153  (e.g. the radially outer surface of the inner cavity  155 ) and the upstream seal  164  of the first connector  44 ′ engages the radially inner surface of the distal end of the neck portion  154 , to seal the fluid in the fluid path  32  as fluid flows from the upstream connector  44 ′ to the downstream connector  46 ′ as shown by the arrows in  FIG.  17   . 
     In this manner fluid can flow down the cavity  160  of the center shaft  158 , radially outwardly through the openings  162  and encounter the poppet valve  80 ′. The poppet valve  80 ′ includes a movable member  168  having a sealing surface  170 , and is biased to an upstream/sealing position by spring  94 ′. When the poppet valve  80 ′ is closed its sealing surface  170  sealingly engages valve seat  172  on the shaft portion  53 , as shown in  FIGS.  18  and  19   . In contrast, when fluid of sufficient pressure acts on the poppet valve  80 ′, the movable member  168  moves downstream, compressing the spring  94 ′, and allowing fluid to flow past the poppet valve  80 ′ as shown in  FIG.  17   . Thus when the assembly  42 ′ is in the configuration shown in  FIG.  17   , under sufficient pressure fluid can flow to the nozzle  18  in the direction of the arrows shown in  FIG.  17   . 
     When an axial separation force is applied to the first  44 ′ and second  46 ′ connectors, the slider  152  moves to a downstream position (in a manner which will be described in greater detail below), as shown in  FIG.  18   . In this position the sealing structure  156  of the slider  152  extends over, and sealingly engages/covers, the openings  162  of the center shaft  158 , and thus blocks fluid flow as or in the manner of a curtain valve. The sealing structure  156  of the slider  152  simultaneously sealingly engages both seals  164 ,  166  of the upstream connector  44 ′ to provide a secure seal. When first  44 ′ and second  46 ′ connectors are properly and fully reconnected, the slider  152  is retracted or moved upstream (in a manner which will be described in greater detail below), and the openings  162  are uncovered such that fluid can flow through the assembly  42 ′. 
     As noted above, the connection structure  147  can include a plurality of axially-extending flanges  148  on the first connector  44 ′, wherein each flange  148  is circumferentially spaced from any adjacent flanges  148 . Each flange  148  may be movable or pivotable in the radial direction (e.g. be moved radially outwardly from the position shown in  FIG.  17    to the position shown in  FIGS.  18  and  19   ). Each flange  148  may be biased to be in its radially outward positions shown in  FIGS.  18  and  19   , by a spring  182  or the like that extends circumferentially around the base ends of the flanges  148  and urges the flanges  148  radially outwardly by a lever force, pivoting about pivot location  188 . Each flange  148  may also be axially coupled to and axially movable with the slider  152 . 
     When the slider  152 /connection structure  147  is in its upstream position or first axial position, as shown in  FIG.  17   , the downstream ends of the flanges  148  are positioned radially inside the attraction member  106   b  and prevented from moving radially outward. This means that the flanges  148  are positioned in the recess  150  and securely grip the downstream connector  46 ′, preventing separation. In contrast, when the slider  152 /connection structure  147  moves to its downstream or second axial position, as shown in  FIG.  18    the downstream end of the flanges  148  protrudes axially beyond the attraction member  106 , enabling the flanges  148  to move radially outwardly, out of the recess  150  and thereby release the downstream connector  46 ′. In this manner, the slider  152  can be positively axially coupled to the downstream connector  46 ′ when the assembly  42 ′ is in the coupled configuration, and the slider or closure valve  152  is released and not axially coupled to the downstream connector  46 ′ when the assembly  42 ′ is in the disconnected configuration. In other words the downstream connector  46 ′ can be configured to move the slider or closure valve  152  to the closed position when the assembly  42 ′ moves from the connected configuration to the disconnected configuration. 
     Each flange  148  may include a surface  180  that is angled (i.e. extending at a non-parallel angle relative to the central axis) on its radially inner surface. The upstream connector  46 ′ may include a ramp or angled surface  190  that engages the ramp or angled surfaces  180  when the slider  152  is in its upstream position as shown in  FIG.  17   . When the slider  152  slides to its downstream position, as shown in  FIGS.  18  and  19   , the angled surfaces  180 / 190  slide axially relative to each other, and the flanges  148  are thereby positively moved to their radially outer position, releasing the downstream connector  46 ′. In contrast, when the slider  152  moves returns to its upstream position (e.g. moving from the position of  FIGS.  18   / 19  to the position of  FIG.  17   ), angled surfaces  191  on the radially outer surfaces of the flanges  148  engage an angled surface  193  on the attraction member  106   b  to positively move the flanges  148  to their radially inner position. However it should be understood that the connection structure  147  can take any of a wide variety of other forms or mechanisms for releasably coupling the slider  152  and the downstream connector  46 ′, such as various ramps, interengaging fingers, interengaging geometry, magnetic couplings, spring connections, etc. 
     A coupling mechanism  41 ′ can be used to secure the slider  152  in its upstream position and thereby axially secure the upstream  44 ′ and downstream  46 ′ connectors, and to solely or primarily supply the separation force to the breakaway assembly  42 ′. The coupling mechanism  41 ′ can include a magnet unit  43 ′ that is coupled to or forms part of the slider  152  that is the same as or analogous to the magnet unit  43 ′ described above. However in this case the magnet unit  43 ′ is coupled to the slider  152  and movable with the slider  152  as will be described in greater detail below. In addition, the assembly  42 ′ can include a pair of attraction members  106   a ,  106   b  that are the same as or analogous to the attraction member  106  outlined above. In particular, the attraction member  106   a  of the embodiment of  FIGS.  17 - 22    is positioned at an upstream end of the upstream connector  44 ′, and magnetically engages the magnet unit  43 ′/slider  152  when the magnet unit  43 ′/slider  152  is in its upstream position to provide the separation force. In addition, the upstream attraction member  106   a  may axially float in the system such that the attraction member  106   a  is axially movable, but constrained in such movement in both axial directions by a fixed body  111  and retaining washer  134 , respectively. The attraction member  106   a  may be biased in the upstream direction by spring or resilient element  138 . 
     The attraction member  106   b  is positioned at a downstream end of the upstream connector  44 ′, and magnetically engages the magnet unit  43 ′/slider  152  when the magnet unit  43 ′/slider  152  is in its downstream position, to provide a desired reconnection force. The magnet unit  43 ′ can be magnetically attracted to the attraction members  106   a ,  106   b , and by the same or variable amounts by for example adjusting the properties of the magnet unit  43 ′ and/or attractions members  106   a ,  106   b  as outlined above. In one embodiment, the attraction of the magnet unit  43 ′ to the downstream attraction member  106   b  (when the slider  152  is in its downstream position) is greater than the attraction of the magnet unit  43 ′ to the upstream attraction member  106   a  (when the slider  152  is in its upstream position). Thus in this case the reconnection force of the assembly  42 ′ may be greater than the separation force. This can provide a safety feature as described in greater detail below. 
     When the assembly  42 ′ is in the fully connected configuration shown in  FIG.  17   , the slider  152  is in its upstream position, and held in position due to magnetic engagement between the magnet unit  43 ′ and the attraction member  106   a . During a breakaway event, a downstream axial force is applied to the second connector  46 ′, which is transmitted to the slider  152  due to the engagement of the ramp  190  of neck portion  154  and the angled surfaces  180  of the flanges  148 . Accordingly, an applied separation force is applied to, and must first overcome, the magnetic attraction between the magnet unit  43 ′ and the upstream attraction member  106   a , which causes the slider  152  to move to its downstream position shown in  FIG.  18   . As the slider  152  moves to its downstream position the distal end of the flanges  148  move axially clear of the attraction member  106   b , which enables the flanges  148  to move to their radially outward position as biased by the spring  182 . This, in turn, causes the flanges  148  to release the downstream connector  46 ′, and the slider  152  fully moves to its downstream position. 
     When the downstream connector  46 ′ is separated from the upstream connector  44 ′, the downstream connector  46 ′ imparts a downstream force to the slider  152 , thereby securely pulling the slider  152  into its closed position to seal the openings  162  by the seals  164 ,  166  as described above. In addition since the slider  152  is moving downstream, the force of the pressurized fluid upstream of the slider  152  urges the slider  152  to its closed position thereby providing a reliable seal. As the downstream connector  46 ′ separates from the upstream connector  44 ′ the poppet valve  80 ′ in the downstream connector  46 ′ is closed as biased by its spring  94 , which can overcome the reduced pressure in the fluid path  32  due to closure of the openings  162 . Thus, after a separation event both connectors  44 ′,  46 ′ can be fluidly sealed in a reliable manner. 
     In order the couple the connectors  44 ′,  46 ′ and move the assembly  42 ′ to its connected configuration, the connectors  44 ′,  46 ′ may begin in an axially-spaced apart position, as shown in  FIGS.  19  and  21   . The connectors  44 ′,  46 ′ are then axially moved together and the second connector  46 ′ engages the slider  152  ( FIG.  18   ) and moves the slider  152  upstream (uncovering the openings  162  and opening the valve  151 ) until the magnet unit  43  engages the upstream attraction member  106   a . Once the second connector  46 ′ is sufficiently axially inserted, the flanges  148  are moved radially inwardly by the angled surfaces  191 , placing the spring  182  in tension. The flanges  148  then engage the ramp  190  and are received in the recess  150  to secure the connectors  44 ′,  46 ′ together. Once the connectors  44 ′,  46 ′ are connected and the curtain valve  151  is open, pressurized fluid flows into the downstream connector  46 ′ and opens the poppet valve  80 ′ therein due to the pressure exerted by the fluid on the poppet valve  80 ′, as shown in  FIG.  17   . 
     In order to move the assembly  42 ′ from its disconnected configuration of  FIG.  19    to its connected configuration of  FIG.  17   , in one case a reconnection tool  202  as shown in  FIGS.  21  and  22    may be utilized. The connection tool  202  includes a pair of manually operable handles  204  that are operable coupled, via various linkages and pivot connections, to a first coupler  206  and a second coupler  208 . The first coupler  206  is a generally annular component configured to closely fit in a recess  210  on an outer surface of the first connector  44 ′. The second coupler  208  is a generally annular component configured to fit over a lip  212  of the second connector  46 ′. 
     When the connection tool  202  is in the configuration shown in  FIG.  21   , and the handles  204  are oriented in a radial direction the first coupler  206  and second coupler  208  are relatively axially spaced apart. The connection tool  202  is then operated such that the handles  204  are pivoted about their pivot points  203  until they handles  204  are oriented in an axial direction, and the first coupler  206  and second coupler  208  are moved axially closer together, as shown in  FIG.  22   , thereby pulling the second connector  46 ′ into the first connector  44 ′ as outlined above. In some cases the tool  202  may be provided to only certified trained personnel to ensure the connection and reconnection process is completed properly and that the system is properly inspected before and after separation. 
     When the slider  152  is in its downstream position ( FIGS.  18  and  19   ), the magnet unit  43 ′ magnetically interacts with, and is thus magnetically coupled to, the downstream attraction member  106   b . The downstream attraction member  106   b  thus acts as a security measure to lock the slider  152 /curtain valve  151  in its closed position, and requires a predetermined force to move the slider  152  away from the downstream position. In particular, the magnet unit  43 ′ and attraction member  106   b  together ensure that a sufficiently high force is required to return the slider  152 /curtain valve  151  to its open position so that only authorized/sufficiently trained personnel can reconnect the assembly  42 ′. This can help to ensure that the assembly  42 ′ is properly assembled and that the parts are in good working order. In one case, the force required to move the slider  152 /curtain valve  151  away from its downstream position is about 200 lbs., or greater than the separation force in one case, or greater than about 25% the separation force in one case, or less than the separation force in one case, or less than about 50% of the separation force in another case. However, the inclusion of the attraction member  106   b  is optional and the attraction member  106   b  can be omitted if desired. 
     In some cases, the downstream connector  46 ′ may include a vent  200  ( FIG.  19   ) in the form of a relatively small opening that provides fluid communication between the fluid path inside the downstream connector  46 ′ (downstream of the poppet valve  80 ′) and the ambient atmosphere. In this case after a separation event when the poppet valve  80 ′ of the downstream connector  46  is closed, the vent  200  allows for a controller release of fluid that may be trapped by the poppet valve  80 ′ to reduce pressure in the system. 
     The assembly  42 ′ of  FIGS.  17 - 22    provides a robust and reliable shut-off valve in which the sealing functionality is provided by the sealing structure  156  of the slider  152  extending over and sealing the openings  162  of the center shaft  158 . In this case the sealing surfaces are entirely positioned inside the assembly  42 ′ in both the connected and unconnected states of the assembly  42 ′ and protected from external forces, and from dirt/debris. The slider  152 /curtain valve  151  allows flow or shuts off flow from radially outside the fluid path  32 /cavity  160 , as the slider  152  seals on the outer surface/diameter of the center shaft  158 . The existence of pressure in the cavity  160  of the center shaft  158 , when the slider  152 /curtain valve  151  is closed, exerts a force radially outwardly. However the slider  152 /curtain valve  151  is moveable axially between its open and closed positions. Thus the existence of radially exerted pressure in the cavity  160 /center shaft  158  does not affect operation of the slider  152 /curtain valve  151 , and the curtain valve  151  is thereby pressure balanced when the slider  152  is in its downstream/closed position, and the pressure of the fluid does not tend to either open or close the curtain valve  151 . In this case an external force is required to open or close the slider  152 /curtain valve  151 . In addition, when the slider  152  is in its downstream position both seals  164 ,  166  engage the slider  152  to thereby trap/close the openings  162  for a strong seal. The curtain valve  151  thus reduces susceptibility to force spikes, although the assembly  42 ′ can include force-spike accommodation features as will be described below. 
     As noted above, the seals  164 ,  166  are captured and internally positioned so that they resist removal. In contrast, in certain other designs the seals can be blown out of position during a separation event, and the person who reconnects the assembly may not notice the missing seals. However, the present design minimizes the chance for displacement of the seals  164 ,  166 . Moreover, the angled surfaces  180  on the flanges  148  that axially connects the two connectors  44 ′,  46 ′ faces radially inwardly and are protected from damages. The corresponding angled ramp  190  faces radially outwardly but is also protected from damage when the assembly  42 ′ is in its connected configuration, and in addition the ramp  190  is easily visible for inspection after a separation event to ensure the ramp  190  is not damaged. 
     In addition, the magnet unit  43 ′ is directly coupled to the slider  152 /curtain valve  151 , which provides a quicker response in terminating the flow of fluid. Many current systems rely on pressure, flow and a biasing spring to close a check valve or the like. In those cases, if there is any debris in the fluid path  32  the valve can be held open and/or slow to close. In contrast, the assembly  42 ′ has no or little surfaces (e.g. surfaces that are perpendicular to the direction of the flow) that debris can collect on to prevent the valve  151  from closing, since the slider  152  is slidably positioned on, and slides axially over, the center shaft  158 . In addition any debris positioned on the center shaft  158  can be displaced and cleaned away by axial sliding of the slider  152  to provide a self-cleaning design. 
     The assembly  42 ′ and in particular the slider  152 /curtain valve  151  design provides a component in which, when the assembly  42 ′ is in its connected configuration, a relatively low number of parts in the upstream connector  44 ′ are exposed to pressure; e.g. the slider  152 , both seals  164 ,  166 , the upstream threaded adapter  48 , the center shaft  158  and internal components of the downstream connector  46 ′. After a separation event, when the curtain valve  151  is closed, the only components of upstream connector  44 ′ exposed to pressure due to pressurized fluid therein are the slider  152 , the valve  151 , the center shaft  158  and the upstream threaded adapter  48 . Thus by providing a relatively low number of parts exposed to pressure, the chances of a loss of pressure are reduced, and cost and complexity of the assembly  42 ′ can also be reduced. 
     As noted above, the angled engaging surfaces  180 ,  190  that transmit the separation force are similarly internally positioned and protected in both states of the assembly  42 ′. Finally, the flow path through the assembly  42 ′ is relatively straight with relatively little turns and change-of-direction provided to the fluid, which reduces pressure forces, reduces wear and tear on the assembly  42 ′, and presents less opportunities for clogs or flow obstructions. 
     Pressure-Spike Accommodation—High Pressure 
     Pressurized fuels may be exposed to pressure spikes due to, for example, connection of the fluid path to a compressor which causes pressure fluctuation during operation of the compressor. Pressure spikes may also occur when an operator jerks on the hose  16 . Since the fluid is compressible, but under relatively high pressure, shock waves (which can come from an upstream source such as a compressor or pump) may propagate through the system relatively quickly, presenting a high pressure spike over a relatively short period of time. 
     During a pressure spike event of the assembly  42 ′ of  FIGS.  17 - 20   , since the assembly  42 ′ is pressure balanced as described above, a fluid-based pressure spike may not directly lead to or cause separation of the assembly  42 ′. Instead, a fluid-based pressure spike from an upstream source may instead apply increased pressure to the seals  164 ,  166 . The seals  164 ,  166  may become temporarily comprised and release or “burp” pressure or fluid into the surrounding volumes, such as inner cavity  155  of the shaft member  153 . It is possible that sufficient burping of fluid or pressure could eventually build up to a degree that relatively strong separation forces are applied to the assembly  42 ′. In addition, an external separation forces, such as a user pulling on the hose  16  can impart separation forces that may need to be accommodated. Thus the pressure-spike/separation force accommodation features outlined above, such as the floating magnet unit  43 ′ and/or floating attraction member  106   a ,  106   b  may be utilized in the assembly  42 ′ of  FIGS.  17 - 20   . 
     In particular, as shown in  FIGS.  17  and  20   , the center shaft  158  of the upstream connector  44 ′ may have a retaining ring  132  received in a recess  130  on an outer surface thereof, retaining the washer  134  in place. When in the coupled arrangement and not accommodating a pressure spike, as shown in  FIG.  17   , an axially-extending gap  195  is positioned between the washer  134  and the attraction member  106   a , and the attraction member  106   a  is biased to the upstream position by spring  138 . 
     When the assembly  42 ′ experiences a pressure spike, the slider  152 , magnet unit  43 ′ and attraction member  106   a , which remains magnetically coupled to the magnet unit  43 ′, can move slightly downstream relative to the rest of the assembly  42 , overcoming the spring force of the resilient component  138  and eliminating the gap  195  as the magnet unit  43 ′ and attraction member  106  move downstream. Such relative movement creates a new gap  197  upstream of the attraction member  106   a , as shown in  FIG.  20   , and compresses the spring  138 . When in the pressure spike accommodating position of  FIG.  20   , if a sufficient separation force is applied to the assembly  42 ′, the magnet unit  43 ′ and slider  152  will separate from the attraction member  106   a  and move downstream, and the assembly  42 ′ will move to the configurations shown in  FIGS.  18  and  19   . However assuming that no separation force is experienced, once the pressure spike force is dissipated, the assembly  42 ′ will return to its position shown in  FIG.  17   , as biased by the spring or resilient component  138  which seeks to expand back to its original position. 
     The gaps  195  and/or  197  can be relatively small, such as between about 0.005″ and about 0.04″, and about 0.02″ in yet another case since the shocks from a compressor/pump or the like may be relatively short in time. The gaps  195 / 197  in this case can be relatively small compared to the gap  137  of the embodiment shown in  FIGS.  2 ,  3  and  13    to ensure that there is not movement in the assembly  42 ′ sufficient to pull any seals out of position. However, the gaps  195 / 197  in the embodiment of  FIGS.  17  and  20    may also be large enough (up to about 0.2 inches in some cases) to accommodate downstream movement of the attraction member  106   a  due to a user jerking on the hose  16  in the same manner that a pressure spike may be accommodated. 
     Thus, it can be seen that that system described and shown herein can provide a fluid dispensing system that can use magnetic features to provide a separation force; that can use magnetic features to accommodate pressure spikes; that can provide valves that are robust and provide strong sealing features; that can accommodate pressure spikes with features other than magnets, and that provide the various other features and advantages described herein. 
     Having described the invention in detail and by reference to certain embodiments, it will be apparent that modifications and variations thereof are possible without departing from the scope of the invention.