Abstract:
A breakaway device joins a portion of a dispensing hose that is connected to a fueling station with a portion of a dispensing hose that is joined to a coupling that connects to a vehicle during fueling. The breakaway device includes a pair of leg members that are joined by their proximal ends to the dispensing hose portions. The distal ends of the leg members are joined at an angle to a frangible member that includes a pair of inner segments that are joined in an abutting fashion by a surrounding frangible sleeve. When a driveaway occurs, the leg members are pulled apart and exert a bending moment on the frangible member. As a result, the frangible member breaks which prevents significant damage to the station. A pneumatic line that provides pressurized air to open the station dispensing valve is attached to each leg member so that when the frangible member breaks, the pneumatic line is ruptured so that pressurized air is no longer delivered to the dispensing valve. As a result, the dispensing valve closes and fuel is no longer delivered to the dispensing hose.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates generally to fueling stations and, more particularly, to a breakaway device for shutting down a fueling station when a vehicle drives away with the dispensing hose of the fueling station attached thereto.  
           [0002]    Both alternative fuels, such as liquid natural gas (LNG), and more conventional fuels, such as gasoline, are dispensed to vehicles via fueling stations. A fueling station typically includes a storage tank holding a supply of fuel, a dispensing hose with a coupling or nozzle that may be removably connected to a vehicle&#39;s fueling port and a pump in series between the storage tank and the dispensing hose for transferring the fuel from the storage tank to the vehicle tank. In the case of LNG or other cryogenic fuels, the fueling station typically includes a conditioning arrangement so that the fuel may be warmed and/or pressurized before delivery to the vehicle. Fueling stations often feature a housing containing some of the system components with the dispensing hose attached to a side of the housing.  
           [0003]    In nearly all fueling stations in the United States, and in many other countries, a breakaway device is installed to the dispensing hose to avoid damage to the fueling station and/or the vehicle being fueled in the event that a user drives away from the fueling station without first disconnecting the dispensing hose from the vehicle. Even with breakaway devices, such “driveaways” can result in substantial repair costs for fueling station operators. In addition, a driveaway is harmful for the environment, and possibly for individuals as well, if a large amount of fuel is spilled.  
           [0004]    Breakaway devices are manufactured by many companies and have various constructions. Virtually all include two pieces which are intended to uncouple when a vehicle drives away from the fueling station with the dispensing hose nozzle or coupling still connected to the vehicle.  
           [0005]    Breakaway devices are commonly installed with one piece connected to the fueling station housing and the other piece connected to the end of the dispensing system hose that is opposite the end that is equipped with the coupling or nozzle. In one example of such an arrangement, the LNG outlet of the fueling station housing is equipped with a vertical brass nipple over which the dispensing hose is placed. A chain is attached between the dispensing hose and an emergency fueling station shutoff valve. As a result, when a driveaway occurs, the dispensing hose is pulled off of the brass nipple and the chain is pulled so that the emergency valve is closed. The chain is sized so as to break in the event that the vehicle continues to drive away from the fueling station. While such an arrangement reduces system damage and stops the flow of fuel from the station, the junction between the dispensing hose and the nipple has a tendency to leak and may also bind when a driveaway occurs so that the fueling station suffers increased damage.  
           [0006]    Improved breakaway devices that connect between and to the fueling station housing and the dispensing hose are illustrated in U.S. Pat. No. 5,520,418 to Burke and U.S. Pat. No. 6,161,872 to Vranicar. The Vranicar &#39;872 patent, however, is primarily directed to a device that prevents binding of the dispensing hose as it is pulled off of the nipple/male connector of the fueling station housing. As such, the breakaway arrangement of the Vranicar &#39;872 patent still suffers from leak and hose spill issues. The Burke &#39;418 patent also prevents binding of the dispensing hose and, in addition, provides an improved junction between the dispensing hose and the fueling station housing. The dispensing hose of the Burke &#39;418 patent includes a valve that shuts when a driveaway occurs. The valve stays with the dispensing hose after the driveaway so that the fluid within the hose does not spill onto the ground. One must contend with the fluid in the entire length of the hose when reconnecting it to the fueling station, however. In addition, while improved, the junction of the Burke &#39;418 patent is still susceptible to leakage issues.  
           [0007]    Very accurate metering of cryogenic liquids during dispensing is sometimes required. The above breakaway devices all feature connectors that are attached to the fueling station housing in a vertical configuration. As a result, the hoses connected to the breakaway devices feature low points wherein liquid may be trapped after dispensing. The cryogenic liquid trapped in the hose must be vaporized and vented from the hoses before accurate dispensing may resume. A breakaway device that permits liquid in the hose to be drained after dispensing is thus desirable when accurate metering is required.  
           [0008]    Alternative breakaway device arrangements feature couplings that are positioned in the dispensing hose a distance away from the fueling station housing. An example of such an arrangement is presented in U.S. Pat. No. 5,050,911 to Morrison. The Morrison &#39;911 patent illustrates a device that includes male and female members that are inserted into adjacent sections of the dispensing hose. An O-ring is positioned between the overlapping joined male and female members as is a frangible locking ring. In the event of a driveaway, the locking ring breaks so that the male member may be pulled out of the female member. As a result, one of the formerly adjacent hose sections remains connected to the fueling station housing while the other remains connected to the nozzle and vehicle. While the device of the Morrison &#39;911 patent is effective, its O-ring seal is susceptible to leakage. This is especially true in the case of cryogenic liquids where thermal cycling occurs at cryogenic temperatures. In addition, the device does not automatically stop the fueling station from operating in the event of a driveaway.  
           [0009]    Several alternative breakaway devices include connectors that are integrated into dispensing hoses and that include valves which close when the hose sections that are joined by the connectors are pulled apart. More specifically, each half of the connector in such an arrangement includes a valve that activates during a driveaway so that fluid within each hose section is not spilled onto the ground. Examples of such an arrangement are presented in U.S. Pat. No. 5,297,574 to Healy; U.S. Pat. No. 5,454,602 to Anderson et al.; U.S. Pat. No. 5,564,471 to Wilder et al.; U.S. Pat. No. 5,695,221 to Sunderhaus; U.S. Pat. No. 5,570,719 to Richards et al.; and U.S. Pat. No. 6,050,297 to Ostrowski et al. The breakaway devices of these patents, however, are complicated and feature many separate parts. This increases their cost of manufacture and the chance of malfunctions.  
           [0010]    Accordingly, it is an object of the present invention to provide a breakaway device for fueling station dispensing hoses that minimizes damage to the fueling station and vehicle in the event of a driveaway.  
           [0011]    It is another object of the present invention to provide a breakaway device for fueling station dispensing hoses that limits the amount of fluid spilled in the event of a driveaway.  
           [0012]    It is another object of the present invention to provide a breakaway device for fueling station hoses that permits liquid remaining in the hose after dispensing to be drained.  
           [0013]    It is another object of the present invention to provide a breakaway device for fueling station dispensing hoses that operates in a consistent and reliable fashion.  
           [0014]    It is still another object of the present invention to provide a breakaway device for fueling station dispensing hoses that does not leak during fuel delivery.  
           [0015]    It is still another object of the present invention to provide a breakaway device for fueling station dispensing hoses that automatically stops the delivery of fuel by the station in the event of a driveaway.  
           [0016]    It is still another object of the present invention to provide a breakaway device for fueling station dispensing hoses that is economical to produce.  
           [0017]    Other objects and advantages will be apparent from the remaining portion of the specification.  
         SUMMARY OF THE INVENTION  
         [0018]    The present invention is directed to a breakaway device for fueling station dispensing hoses. The breakaway device joins first and second portions of the dispensing hose where the first dispensing hose portion is connected to the fueling station and the second dispensing hose portion is connected to a coupling that connects to a vehicle during fueling. The breakaway device prevents significant damage to the station and spillage of fuel in the event of a driveaway.  
           [0019]    The breakaway device features a pair of leg pipe members that are connected by their proximal ends to the dispensing hose portions and by their distal ends to a frangible pipe member. The leg members are oriented at an angle relative to the frangible member so that a bending moment acts on the frangible member when opposing forces exerted on the dispensing hose portions, such as during a driveaway, pull the leg members generally away from one another.  
           [0020]    The frangible member is constructed to fracture when sum of the opposing forces pulling the proximal ends of the leg members generally away from one another exceeds a predetermined value, preferably around 400 lbs. The frangible pipe member preferably includes inner segments connected to the distal ends of the leg members with their tapered end portions secured in an abutting relationship by a surrounding frangible sleeve.  
           [0021]    The breakaway device also includes a pneumatic line bracket attached to the proximal end of each leg member. The brackets receive a pneumatic line that provides pressurized air for opening the station dispensing valve. The pneumatic line is ruptured when the frangible member breaks and the leg members are pulled apart. As a result, the supply of pressurized air to the dispensing valve of the station is interrupted so that it closes and fuel is no longer delivered to the dispensing hose.  
           [0022]    The following detailed description of embodiments of the invention, taken in conjunction with the appended claims and accompanying drawings, provide a more complete understanding of the nature and scope of the invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0023]    [0023]FIG. 1 is a schematic of a fueling station that is equipped with an embodiment of the breakaway device of the present invention;  
         [0024]    [0024]FIG. 2 is an enlarged schematic view of the control system for the fueling station of FIG. 1;  
         [0025]    [0025]FIG. 3 is an enlarged side elevational view of the breakaway device of FIGS. 1 and 2;  
         [0026]    [0026]FIG. 4 is an enlarged front elevational view of one of the pneumatic line brackets of the breakaway device of FIGS.  1 - 3 .  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0027]    A fueling station that is equipped with an embodiment of the breakaway device of the present invention is indicated in general at  8  in FIG. 1. The fueling station  8  delivers a metered quantity of Liquid Natural Gas (LNG) to a vehicle. While the breakaway device of the present invention is described below with reference to an LNG fueling station, it is to be understood that the device may be effectively employed in systems or stations that dispense fuels or liquids other than LNG, including both cryogenic and non-cryogenic liquids.  
         [0028]    The fueling station  8  includes a jacket-insulated bulk storage tank  10  for storing a large volume of LNG  12 . An insulated line  14  connects the storage tank to  10  to a meter sump  15  and includes a shut-off valve  16 . Meter sump  15  is partially filled with LNG  18  and the vapor spaces  20  and  22  of storage tank  10  and meter sump  15 , respectively, are connected by a vapor return line  24 , which also includes a shut-off valve  25 . Meter sump  15  features a jacketed construction for insulation purposes.  
         [0029]    When dispensing of LNG from the station to a vehicle is desired, LNG is transferred from storage tank  10  to meter sump  15  via pressure differential or the action of a cryogenic liquid pump  26  that is incorporated in line  14 . Due to the pressure head within the meter sump  15 , LNG therein is displaced by the LNG entering from tank  10  and forced out through dip tube  27 , dispensing line  28  and dispensing hose  30  so as to flow into a vehicle tank. Alternatively, the pressure within the meter sump may be sufficient to dispense LNG to the vehicle tank without the introduction of LNG from the storage tank  10 . Dispensing hose  30  terminates in a quick-disconnect coupling  32  that may be removably connected to a corresponding coupling on the vehicle. Dispensing line  28  is provided with a pneumatically-operated dispensing valve  34  which, as will be explained in greater detail below, is selectively in communication with a source of pressurized air.  
         [0030]    When dispensing of LNG ceases, and dispensing valve  34  is closed, an undelivered volume of LNG remains in the system dispensing hose  30  of FIG. 1. Ambient heating will require that the resulting LNG vapors in the hose be vented. In addition, an unknown volume of LNG remaining in the dispensing hose undermines accurate metering during the next dispensing. Accordingly, it is desirable that the hose be empty at the commencement of dispensing, that is, that the system provide a “dry hose.” As illustrated in FIG. 1, the station provides this by the inclusion of a drain line  40  connected on opposite sides of dispensing valve  34 . The outlet  39  of the drain line  40  communicates with sump  15  via the portion of the dispensing line  28  proceeding the dispensing valve  34 . The inlet  43  of the drain line  40  is connected at the lowest level  45  along dispensing line  28  and hose  30  between the sump  15  and the quick-disconnect coupling  32 . Drain line  40  is provided with a check valve  44  to prevent LNG from sump  15  bypassing closed dispensing valve  34 . A housing  50  surrounds the meter sump  15 , dispensing line  28 , dispensing valve  34 , drain line  40  and check valve  44 .  
         [0031]    In operation, at the end of dispensing, the dispensing valve  34  is closed and ambient heat pressurizes the LNG trapped in the hose  30  so that the liquid is quickly forced through drain line  40 , check valve  44  and back into sump  15 . If the inlet  43  of the drain line  40  was not at the lowest level in the pathway (dispensing line  28  and hose  30 ) between sump  15  and coupling  32 , the LNG would only transfer out of the hose via the drain line as a gas because the liquid would collect at the lowest level in the pathway, away from the drain line inlet  43 . This could possibly and undesirably leave LNG in the hose at the commencement of the next dispensing.  
         [0032]    An embodiment of the breakaway device of the present invention  52  is positioned in hose  30 . The breakaway device is configured to separate into two pieces when a vehicle drives away from the station  8  with the coupling  32  still attached. The breakaway device  52  thus provides driveaway protection while surviving the thermal cycling that occurs when LNG is dispensed. In addition, the breakaway device still permits the inlet  43  of the drain line  40  to be at the lowest level in the pathway between sump  15  and coupling  32 . As a result, liquid from the hose drains through drain line  40 , passes through check valve  44  and ultimately is deposited in sump  15  so that a dry hose condition is present at the start of the next dispensing cycle.  
         [0033]    The control system of the fueling station of FIG. 1 is illustrated in FIG. 2. A programmable logic controller  60  communicates with and controls a solenoid valve  62  via wire  64 . The solenoid valve  62  receives air from a source of pressurized air (not shown) via line  66 . When controller  60  configures solenoid valve  62  to the open position, pressurized air travels through pneumatic line  68  to the pneumatic dispensing valve  34  so that it is also open. In other words, pneumatic dispensing valve  34  is open when it is receiving pressurized air from open solenoid valve  62 .  
         [0034]    Pneumatic line  68  is preferably constructed from ⅜″ brake line tubing. As illustrated in FIG. 2, a portion of pneumatic line  68  runs parallel to the dispensing hose  30  and, as will be explained in greater detail below, is secured at the inlet  56  of the breakaway device  52 . The pneumatic line  68  then traverses the breakaway device and is connected at the outlet section  72  of the breakaway device  52 . The pneumatic line  68  then makes a U-turn and once again is connected to the outlet section  72  and inlet section  56  of the breakaway device. The pneumatic line  68  then travels to the pneumatic dispensing valve  34 .  
         [0035]    The breakaway device, indicated in general at  52  in FIG. 3, features an inlet section  56 , outlet section  72 , elbows  74   a - 74   d  and leg pipe members  82   a  and  82   b , all constructed from piping which is capable of withstanding cryogenic liquids and their temperatures or whatever fuel is being dispensed. The leg members have proximal ends  83   a  and  83   b  and distal ends  85   a  and  85   b . In the case of LNG, an example of a suitable pipe material is 304 stainless steel. The breakaway device also includes a frangible cross member, indicated in general at  84 , that has an inlet end  87  connected to elbow  74   b  and an outlet end  89  connected to elbow  74   c  so as to extend between the distal ends  85   a  and  85   b  of leg members  82   a  and  82   b.    
         [0036]    The longitudinal axis  91  of frangible member  84  preferably makes an angle  93  of approximately 90° with the longitudinal axis  95  of each leg member. Leg member  82   a  preferably also makes an angle  97  of approximately 90° with the longitudinal axis  99  of inlet section  56 . The angle between the longitudinal axes of leg member  82   b  and outlet section  72  is also preferably 90°. As a result, the members and elbows of the breakaway device form a loop through which the LNG travels as it is being dispensed. It should be noted that while straight pipe members are illustrated for the leg and frangible members with 90° angles between each, the pipe and frangible members may be curved and the angles may differ so that breakaway device  52  has more of an arc-shaped or inverted U-shaped profile.  
         [0037]    The frangible cross member preferably is constructed from inner segments  86   a  and  86   b  which are attached to elbows  74   b  and  74   c , respectively. The end portions  92   a  and  92   b  of inner segments  86   a  and  86   b  are joined in an abutting fashion by a sleeve  88  and are tapered slightly. While inner segments  86   a  and  86   b  are constructed of the same material as the elbows, leg members and cross member of the breakaway device, the sleeve is constructed of a relatively brittle material such as brass and fits around inner segments  86   a  and  86   b  in an interference fit fashion. It should be noted that, as an alternative to the multi-piece construction illustrated in FIG. 3, the frangible cross member  84  could be constructed from a single-piece pipe section. Either arrangement is much less prone to leakage than an O-ring sealing arrangement.  
         [0038]    The pneumatic line  68 , as described previously, traverses the breakaway device in a parallel configuration. The parallel portions of the pneumatic line are attached to elbows  74   a  and  74   d  of the breakaway device by pneumatic line brackets  94   a  and  94   b . As illustrated in FIG. 4, bracket  94   b  is essentially a tab that features openings  102   a  and  102   b . Bracket  94   a  features the same construction and includes openings  104   a  and  104   b  (FIG. 3). Brackets  94   a  and  94   b  preferably are constructed from stainless steel and are secured to their respective elbows by weldment. The pneumatic line  68  passes through opening  104   a  of bracket  94   a  and then opening  102   a  of bracket  94   b . The pneumatic line then makes a U-turn and passes through opening  102   b  of bracket  94   b  and opening  104   b  of bracket  94   a . Collars  106   a  and  106   b  secure the parallel portions of pneumatic line  86  to bracket  94   a . Collars  106   a  and  106   b  are constructed of stainless steel and are secured to the pneumatic line by a compression fitting and to the bracket  94   a  by a threaded connection.  
         [0039]    When a driveaway occurs, that is, when a vehicle drives away from the fueling station  8  of FIG. 1 with the coupling  32  still attached to the vehicle, the breakaway device  52  of FIG. 3 is subjected to opposing forces in the directions indicated by arrows  108   a  and  108   b . Due to leg members  82   a  and  82   b , frangible cross member  84  is subjected to a predictable bending moment indicated by arrows  110   a  and  110   b . Under the influence of the bending moment, the end portions  92   a  and  92   b  of inner segments  86   a  and  86   b  pivot against one another aided by their tapered design. As the end portions of the inner segments pivot against one another, the sleeve  88  of the cross member eventually fractures or breaks and inner segments  86   a  and  86   b  are separated from one another. As a result, leg member  82   a  and inner segment  86   a  remain attached to first dispensing hose portion  31   a  (FIG. 2), which remains attached to the station housing  50 . In contrast, leg member  82   b  and inner segment  86   b  remain attached to second dispensing hose portion  31   b  (FIG. 2), and thus to coupling  32  which is still connected to the vehicle.  
         [0040]    The breakaway device  52  fractures into two pieces preferably when the sum of the forces acting thereon in the directions indicated by arrows  108   a  and  108   b  totals to 400 lbs. When the sleeve is constructed of brass having a wall thickness of approximately 0.030 inches, and angles  93  and  97  (FIG. 3) are approximately 90°, it has been found that a length for the leg members ( 112  in FIG. 3) of approximately six inches with a length for the frangible cross member ( 114  in FIG. 3) of approximately three inches results in the breakage device fracturing when the forces acting on the device in the directions of arrows  108   a  and  108   b  total to 400 lbs.  
         [0041]    As the leg members  82   a  and  82   b  are rotated away from one another, in the directions of arrows  110   a  and  110   b  in FIG. 3, bracket  94   b  engages the U-turn  122  of pneumatic line  68  and pulls it away from bracket  94   a  and the section of pneumatic line  68  secured thereto. Due to the resulting strain placed on the parallel portions of pneumatic line  68 , it eventually ruptures between brackets  94   a  and  94   b  so that the flow of pressurized air to automated dispensing valve  34  is interrupted. This results in pneumatic dispensing valve  34  closing so that the transfer of LNG from the meter sump  15  to the dispensing line  28  and hose  30  is halted.  
         [0042]    The small amounts of pressurized LNG remaining in hose portion  31   a , that remains attached to the station housing  50 , and hose portion  31   b , that remains connected to the vehicle, spray onto the ground and quickly evaporates.  
         [0043]    While the preferred embodiments of the invention have been shown and described, it will be apparent to those skilled in the art that changes and modifications may be made therein without departing from the spirit of the invention, the scope of which is defined by the appended claims.