Abstract:
A dual-mode propane fuel dispenser apparatus and a metal skid framework supporting a bottled gas dispensing station on one side and a motor vehicle fuel pump carried at an opposite side. Dispensing nozzles at each side are coupled to a common supply tank and solenoid valves are used to control flow to the selected dispenser. The bottled gas station has a scale to measure weight to determine when the container is full. The fuel dispenser includes a meter which determines the volume of fuel dispensed. A computer and visual displays are provided to show amounts dispensed to either a vehicle tank or bottled gas container and the price charged for each.

Description:
FIELD OF THE INVENTION 
     This invention relates to dispensing of liquid petroleum gas (LPG) and more particularly to methods and apparatus for dispensing of propane gas to motor vehicle tanks and to portable bottled gas containers. 
     BACKGROUND OF THE INVENTION 
     “Propane” strictly speaking relates to a specific alkane hydrocarbon compound of the same family as methane, ethane, butane and others. Propane is a component of natural gas, and it can be separated from other components by compressing and cooling the natural gas mixture until propane becomes liquefied. Propane is also obtained as a by-product in fractional distillation of petroleum. The liquefied gas from these sources is sold commercially as bottled gas fuel distributed to customers in small portable containers and as a motor vehicle fuel used in engines adapted for this purpose. 
     Commercially available propane fuel is conventionally designated as “propane” despite small amounts of other gasses such as methane, ethane, butane and other hydrocarbon gasses mixed with the propane. Up to about 5% or so (in the United States) of such other components may be included. In the present application, it is to be understood that “propane” is intended to refer to commercially available fuel mixtures so designated which may include other gasses. 
     Although the composition of propane fuel as bottled gas and motor fuel applications may be the same in each case, the apparatus and method used in measuring the amount dispensed and determining the price to retail customers varies significantly. Bottled gas fuel is stored and transported in pressurized, portable metal cylinders which typically hold anywhere from about 2.5 pound to 100 pounds of gas. Many of the customers for bottled gas fuel are owners of recreational vehicles such as motor homes and trailers who take advantage of the convenience afforded by the portability of this fuel. Filling of bottled gas containers is generally carried out as a refilling service at a standard charge based on the amount of liquified gas needed to fill an empty tank. This type of service does not take into account residual amounts of liquid gas in the container, meaning that the customer pays more per unit of liquified gas received if the tank is not empty. Completion of filling is determined by weight, which requires the presence of a suitable scale. Propane motor fuel, on the other hand, is dispensed and sold in certain areas of the country in much the same manner as gasoline and diesel fuel, that is by dispensers installed at filling stations, the dispensers metering purchased fuel by volume and automatically displaying the price, based on gallons delivered. In many instances, propane is sold both as bottled gas and motor fuel at the same retail establishment, which may be a convenience store or filling station. Here, vehicles are typically fueled at a service island, while the bottled gas refueling facility is a separate facility some distance away from the service island. Under these circumstances, it would be advantageous to provide an integrated propane dispensing facility which would enable serving both markets and which would use, to the extent possible, the same equipment for both. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a dual purpose propane dispensing system comprising apparatus appropriate for a bottled gas dispensing station disposed in an enclosure on one side of a supporting frame and a propane motor vehicle dispenser disposed on the other side thereof or in close proximity thereto. The system is adapted for installation on a common service island of a filling station and for being connected to a propane supply line provided at the island. A scale and a pressurized dispensing nozzle coupled to the supply line are housed in the enclosure on the bottle gas side, the enclosure provided with a lock securing the nozzle when not in use. The propane motor vehicle fuel dispenser on the other side may have the same fuel delivery features as in previously known propane dispensers, but is modified to enable input data obtained from flow of bottled gas to be fed into the electronic metering and price display components of the dispenser so as to provide a display of the price for dispensed bottled gas. Flow of fuel from the supply line to the selected nozzle, either the bottled gas nozzle or the motor vehicle dispenser nozzle, may be controlled by switching of solenoid-actuated valves controlling flow to the nozzles. Price calculations made by the computer may be controlled to reflect the different tax treatment of motor vehicle fuel and bottled gas. 
     The dual purpose system of this invention is designed for preassembly at a factory or shop, with only the steps of bolting the supporting skid to a concrete pad of a service island, making connections to a liquid supply line, vapor lines and an electrical source being required. 
     This system also provides a complete retail propane refueling system at a single location, allowing bottled gas containers and motor vehicle tanks to be filled quickly and conveniently. Further advantages are provided by the rugged construction and professional appearance presented to the customer. Unlike prior practice, this approach also provides a fairer result to those seeking bottled gas by only charging for the amount of fuel delivered. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front elevational view showing a fuel dispensing system embodying the invention with a scale enclosure thereof closed. 
     FIG. 2 is a view as in FIG. 1 with a cover of the enclosure lifted. 
     FIG. 3 is a plan view of the skid shown from below. 
     FIG. 4 is a side view of the scale enclosure, with one side removed for purposes of clarity. 
     FIG. 5 is a three-dimensional view showing scale-support structure; and, 
     FIG. 6 is a block diagram showing control features of the apparatus. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIG. 1 of the drawings, there is shown a dual-mode propane dispenser system  10  comprising a motor vehicle fuel dispenser  12  and a bottled gas dispenser and scale enclosure  14  integrally constructed in side-by side relationship on a skid  16  in position on a concrete pad  18  of a service island  20 . The service island extends about  6  inches or so upward from the surface of the surrounding pavement and typically has a pair of inverted U-shaped guard posts  22 ,  23  (or alternately a series of posts or the like) embedded therein to provide protection from being hit. Dispenser  12  has a hose  26  connected at one end to fitting  28  extending outward from the dispenser (not shown) and at the other end to a nozzle  30  from which fuel is dispensed. Fuel hose  26 may or may not incorporate includes a fuel supply line and a vapor return line. 
     As shown in FIG. 2, enclosure  14 , with hinged cover lifted in this view, has a platform scale  34  placed therein for weighing of bottled gas containers to determine when the container is full. Alternately, by use of suitable equipment, an electronic indication of weight may be obtained and provided to the computer for controlling flow of fuel. Fuel line  36  extends into the enclosure from assembly  12  and terminates at nozzle  38  through which bottled gas is dispensed. 
     Skid  16  (FIGS. 3-5) comprises a rugged metal framework upon which components at the dispenser  12  and enclosure  14  may be securely connected, providing a one-piece, preassembled installation at a customer site. Skid  16  preferably takes the form of a rectangular framework structure having vertical side panels extending around its periphery, including panels  40 ,  42  along the length of the skid and panels  44 ,  46  across the ends thereof. The skid is divided into two portions placed in contact side by side, a first portion  48  supporting a scale and bottled gas dispenser enclosure  14  and a second portion  52  supporting a motor vehicle fuel dispenser assembly  12 . Panels  54 ,  56  extend across the skid at the juncture of the two portions, these panels being secured together by bolts (not shown). Owing to differences in internal structure of the respective portions it is preferred to fabricate them separately and then bolt them together to obtain a one-piece skid. 
     Side panels of the enclosure portion each have a bent-over flange  58  (FIG. 4) at a bottom edge thereof, providing a base upon which the skid rests. The flanges are connected to pad  18  of the island by bolts (not shown) which extend through holes  60 . Horizontal flange strips  61  are also provided at top edges of the skid panels at the dispenser portion of the skid. 
     A rectangular frame  62  (FIG. 5) is provided in enclosure portion  14  of the skid, the frame made up of two pairs of rails, one pair  64  having a L-shaped cross section extending in a direction parallel to panel  56  and a second pair of rails  66  perpendicular to rails  64 . The rails may be secured to panels of the skid by having their ends connected to the panels, as by welding. One leaf  65  of the L-shaped rails is disposed parallel to the bottom edges of the skid at a distance such as one inch from the floor and the other leaf  67  is vertically disposed in position to secure a platform scale base from slipping. A platform scale is positioned with side edges of its base in close proximity to vertical portions of the rails. 
     Enclosure  14  has a front wall  69 , a back wall  68 , side walls  70 ,  72  and a top  74 , all made of rigid metal such as a heavy aluminum plate. Bottoms of the sides and back wall are secured to top edges of panels underneath by means such as welding. Access to the scale and dispenser is enabled by mounting of the front wall  69  and top wall  74  on hinges  76 ,  78  located at the juncture of the top and back walls and at the juncture of the front wall and the top. Back wall  68  extends higher than front wall  69  so as to facilitate lifting the front wall up and folding it toward the rear. A catch  71  into which a lower edge of the front wall is placed extends from an internal side, and is used to hold up the front wall during filling of a propane bottle. 
     For providing security when the bottled gas dispenser is not in use, a lock  80  coupled to a T-handle closure  82  may be provided near the lower edge at the front wall. The lock is adapted for engagement with a mating slot  84  in the front flange strip of the skid. 
     Motor vehicle dispenser portion  52  of the skid has a horizontal bottom flange  86  extending around its periphery integral with vertical panels  54 ,  42 . This flange is provided with holes  88  for securing the flange to the underlying pad  18  by means of bolts (not shown). Integral with the vertical panels a horizontal upper flange  90  extends around the same periphery providing a base member upon which the dispenser is attached. Holes  19  are provided for placement of bolts (not shown) for securing the dispenser to the skid. Knockout plugs may be provided in one or more vertical panels for introduction of a fuel supply line and wires or cables where such are not already available at a central location on the service island. 
     Control features of the invention are shown schematically in FIG.  6 . Storage tank  92  is connected to a pump  94  which provides pressurized flow of liquid propane fuel. Quantity of dispensed fuel is measured by meter  96 , which provides electronic signals indicative of volume to the dispenser control computer. Selection of the desired delivery mode is enabled by opening solenoid valve  98  coupled to nozzle  30  by operation of switch  104  or solenoid valve  100  coupled to nozzle  38  by operation of switch  106 . Data based on quantity and delivery mode is provided to price computer  102 , which calculates and displays the price to be charged. A vapor return line  104  is provided to return vapor from meter  106  to the storage tank  92 , and liquid bypass mechanism  106  senses excess pressure downstream of pump  94  and returns the sensed excess back to the tank. 
     Component equipment for apparatus of this invention may comprise commercially available pumps, nozzles, scales and the like. Motor vehicle pump assemblies which may be used are available from SQUIBB-TAYLOR, Inc. at 10480 Shady Trail, #106, Dallas, Tex. Suitable nozzles that provide temperature compensation and control of operating pressure are available from LG EQUIPMENT, Unit #29, 58 Box Road, Taren Point, New South Wales, Australia. A computerized flow control and price calculator provided by the KRAUSE GROUP, Inc., at 25 Paquin Rd, Winnipeg, Mannatoba, Canada, may be used, and which calculates price information from data obtained from a flow meter obtainable from LIQUA-TECH located at 3501 North State Street, Ukiah, Calif.