Dual mode propane fuel dispensing apparatus and method

[0002] 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.

[0003] “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.

[0004] 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.

[0005] 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.

[0006] 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.

[0007] 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.

[0008] 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.

[0009] FIG. 1 is a front elevational view showing a fuel dispensing system embodying the invention with a scale enclosure thereof closed.

[0010] FIG. 2 is a view as in FIG. 1 with a cover of the enclosure lifted.

[0011] FIG. 3 is a plan view of the skid shown from below.

[0012] FIG. 4 is a side view of the scale enclosure, with one side removed for purposes of clarity.

[0013] FIG. 5 is a three-dimensional view showing scale-support structure; and,

[0014] FIG. 6 is a block diagram showing control features of the apparatus.

[0015] 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 26may or may not incorporate includes a fuel supply line and a vapor return line.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.