US3294079A

US3294079A - Adapter to permit the burning of lpg fuels in normally liquid-fuel burning stoves

Info

Publication number: US3294079A
Application number: US461781A
Authority: US
Inventors: Richard R Thompson
Original assignee: Individual
Current assignee: Individual
Priority date: 1965-06-07
Filing date: 1965-06-07
Publication date: 1966-12-27
Anticipated expiration: 1983-12-27

Description

Dec. 27, 1966 R. R. THOMPSON 3,

ADAPTER TO PERMIT THE BURNING OF LPG FUELS IN NQRMALLY LIQUID-FUEL BURNING STOVES Filed June '7, 1965 R/CHARD R. THOMPSON lA/VE/VTUR BY 59 BUCKHOEW, BLORE, KLAROU/ST a SPAR/(MAN nited States Patent Gfifice 3,294,079 Patented Dec. 27, 1966 3,294,079 ADAPTER T PERMIT THE BURNING 0F LPG FUEFE IN NQRMALLY LlQUlD-FUEL BURNING STOVES Richard R. Thompson, Rte. 2, Box 55, Oregon City, Greg. 97405 Filed June 7, 1965, Ser. No. 461,781 7 Claims. (Ql. 12638) The present invention relates to liquid petroleum gasburning stoves and more particularly to an adapter which permits the burning of liquid petroleum gas fuels such as propane and butane in normally liquid-fuel burning camp stoves and the like.

Camp stoves have become an almost indispensable item for campers, and most camp stoves are designed to burn gasoline or other liquid fuels. However, such liquid-fuel burning stoves have several annoying disadvantages, probably the most annoying of which are the all-toofrequent pumping of air into the fuel tank required to maintain a desired heat and flame and the frequent refilling of the fuel tank required. Spillage of fuel during refilling is difficult to avoid, and consequently fuel odors are usually present while such stoves are in use. In addition, carbon tends to collect at certain points in the fuel distribution systems of gasoline stoves so as to require cleaning from time to time to keep them working properly, and carbon also collects on utensils exposed to their flame.

Liquid petroleum gas (LPG) has numerous advantages over gasoline and other liquids as fuel for camp stoves, among which are its cleanness, low cost, hotter flame and constant heat. LPG fuels are conveniently stored in refillable tanks in pressurized liquid form so that spillage is no problem.

Accordingly, a primary object of the present invention is to provide a new and improved method of adapting a normally liquid-fuel burning stove for burning LPG fuels.

Another primary object is to provide a novel device for converting a normally liquid-fuel burning stove to one for burning LPG fuels.

A more specific object is to provide a conversion device which quickly and easily adapts a conventional gasolineburning camp stove for burning LPG fuels.

A further object is to provide a novel device as described which is simple to construct, install and operate.

Sitll another object is to provide a device as described which is only temporary and which enables the stove to be converted back to its original gasoline-burning condition rapidly and easily.

Another object is to provide a device as described which is compact, portable and easily removable from the stove for storage in transit.

Another object is to provide a device as described which is constructed of a relatively few number of inexpensive parts and which utilizes most of the original parts of the stove.

The above and other objects and advantages will become more apparent from the following detailed description which proceeds with reference to the accompanying drawing wherein:

FIG. 1 is a perspective view of a gasoline camp stove with a conversion device in accordance with the invention attached thereto;

FIG. 2 is an enlarged view of the conversion device of FIG. 1, partly in section;

FIG. 3 is a view on a slightly larger scale than FIG; 1 illustrating a conventional gasoline supply tank supplied 7 as an original part of the camp stove and the valve and generator assembly connected thereto;

FIG. 4 is a fragmentary perspective view, on an enlarged scale, showing a portion of the camp stove of FIG. 1 and a portion of the conversion device attached thereto in its operative position;

FIG. 5 is a perspective view on a greatly enlarged scale showing a leveling block which forms a portion of the conversion device.

With reference to the drawings, FIG. 1 illustrates a conventional gasoline-burning camp stove 10 of the Coleman type mounted on a stand 12 and including a sheet metal base portion 14 in which a pair of burners 15 are provided, and a cover 16 which serves as a windshield when upright as shown. A gasoline tank 17 and connected valve and generator assembly 18 (FIG. 3) are normally mounted on the outside front wall 19 of the stove, but when burning LPG fuel, such tank is removed from the stove and replaced with the conversion device of the present invention shown generally at 20 connected to a tank, or cylinder, 21?. of liquid petroleum gas (LPG) fuel stored under high pressure in liquid form.

The conversion device is shown in greater detail in FIG. 2 and includes as its principal parts an adjustable diaphragm-type pressure regulator, or reducing valve, 24, a length of flexible hoseio, a shut-off valve 28 and an elongate, hollow rigid tube 3t having a small discharge orifice 32 at its terminal end. The tube 3t) is in actuality the generator tube provided with the usual gasoline stove as a part of the needle valve and generator assembly 18 to transfer the fuel from the tank 17 to the main burner 15, with the exception that the usual needle valve assembly 33 and encircling coil 34 have been removed from the interior of the tube as shown in FIG. 3.

Threaded onto the end of the generator tube opposite the orifice 32 is an elongate coupling 36 connecting the tube to the outlet end of a housing 38 for shut-off valve 28. The shut-off valve 2% is of a conventional needle type, and is opened and closed by means of a handle 39. The inlet end of the shut-off valve housing is threadedly connected by a coupling 49 to one end of a hose fitting 41 on the flexible hose 26, and the opposite end of the hose is threadedly connected by another hose fitting 42 to the outlet end of a housing 44 for the reducing valve 24. The reducing is of a well-known construction and includes a threaded adjustment member 46 for regulating the valve for the amount of pressure reduction desired. The inlet end of the reducing valve housing is threadedly connected to a fitting 48 which includes a threaded sleeve coupling 49 slidable on the fitting for threadedly attaching the reducing valve-end of the conversion device to the upper end of the LPG fuel tank 22 at the shut-off valve for the tank.

In addition to the foregoing elements, the device includes as an important feature a means in the form of a spring clip 50 for rigidly but releasably attaching the tube 39 and shut-off valve to the camp stove. The spring clip includes a ring 52 which encircles the valve housing 38 in an annular depression 53 created at the juncture between the housing 38 and the elongate coupling 36 joining the housing to the generator tube. The ring is sufliciently small in diameter so that it cannot slip over the coupling and cannot be removed from the device without unthreading the coupling from the valve housing. However, the ring is sufficiently large so that it can swivel in the groove 53. The ring has an eye 54 to which is connected one end of a relatively long coil spring 55. The opposite end of the spring is connected to one end of a clip 58 having a hook 59 at its other end.

With reference to FIG. 4, the tube 30 extends into the 0 camp stove through the usual opening 60 in the front face usual manner. A leveling block 64 having a slot 66 in one side, as clearly shown in FIG. 5, is placed in the opening 60 with the bottom edge of the opening extending into the slot. The rear end of the tube rests on the upper surface of the block to level the same. The spring clip 50 is hooked on an edge of one of the vent openings 68 provided in the bottom of the stove to stabilize the tube and shut-off valve.

To convert the gasoline camp stove shown for use with LPG fuel, the gasoline tank 17 is first removed from the stove and the generator tube 30 unscrewed from the valve fitting 18 on the top of the tank. Then the needle assembly 33 and coil 34 surrounding the assembly are removed from within the tube, and any existing carbon is cleaned from the tube and its orifice 32. Following this, the generator tube is threaded into the end of the coupling 36 of the convention device, which is preassembled in the form shown in FIG. 2.

With the generator tube now forming a portion of the conversion device, the leveling block 64 is placed in the front opening 60 of the camp stove, and the generator tube is inserted through the opening and into the fuel inlet opening 62 of the main burner. The spring clip is then hooked to the underside of the stove to place the spring 56 in tension and thereby affix the tube and valve housing rigidly to the stove. Following this, the fitting 48 at the regulator end of the conversion device is connected to the standard valve fitting 7 provided at the upper end of the cylinder 22 of LPG fuel by tightening the sleeve coupling 49.

With the device now attached to both the stove and to the LPG fuel supply, the valve 70 on the cylinder is opened to force fuel through the device down to the shutoff valve 28.

Thereafter a burning match is placed adjacent the master burner 15 and the handle of the shut-off valve turned to open the valve, thus sending fuel to the main burner and igniting the same instantly. The height of the flame at the main burner can be controlled by opening or closing the shut-off valve slightly to control the flow of gas. The stoves other burner can then be ignited by opening the individual control valve 72 therefor and igniting it with a match in the usual manner.

With the device as described, a gasoline camp stove can be quickly and easily adapted for burning LPG fuel and conversely, the stove can be converted back to use as an ordinary gasoline stove simply by removing the generator tube from the conversion device, reinserting the needle valve assembly 33 and coil 34 into the tube, reattaching the tube to the valve fitting 18 on the tank, and thereafter attaching the tank 18 to the stove in the usual manner.

It has been found that my conversion device works best when the pressure regulator is adjusted to deliver an outlet pressure of from to 35 pounds per square inch. I have also found it preferable to provide all-brass fittings and to seal the same with a heavy-duty acryli or equivalent coating to preserve the finish and weatherproof the device. With my device I have been able to operate an ordinary gasoline camp stove for forty hours or more with one gallon of LPG fuel costing less than fifty cents.

Having illustrated and described a preferred embodiment of my invention, it should be apparent to those skilled in the art that the invention permits of modification in arrangement and detail. In any event, it is to be understood that my invention is not to be limited other than by the following claims.

I claim:

1. A conversion apparatus for use in combination with a liquid-fuel burning stove for converting said stove to use with liquid petroleum gas fuels, said stove normally including a burner with a fuel inlet and a generator tube connected to a liquid fuel tank and having a rod and coil within said tube, said apparatus comprising:

a length of flexible hose,

a reduction valve means connected to one end of said hose,

connector means adapted for connecting said reduction valve means to a pressurized supply of liquid petroleum gas fuel,

a shut-off valve means connected to the other end of said hose,

said shut-off valve means including a housing provided with a connector means adapted for connecting said housing to the generator tube of the liquid-fuel burning stove after the tube has been disconnected from its fuel tank and after the rod and coil have been removed from within said tube,

and releasable attachment means adapted for rigidly attaching said shut-off valve housing to the stove with said shut-off valve positioned outwardly of and adjacent said stove.

2. A conversion apparatus according to claim 11 wherein said attachment means includes a leveling block adapted for supporting one end of said generator tube at a sidewall opening in said stove, said block member including a slot therein for retaining said block on the bottom edge of said opening, and spring clip means connected at one to said housing and having a free end adapted to hook onto said stove.

3. A conversion apparatus according to claim 1 wherein said attachment means includes a resilient means attached to said housing and a hook member attached to said resilent means.

4. In combination with a gasoline-burning camp stove having a main burner, a fuel inlet opening for said burner, a base having a sidewall access opening into the interior of said base and a bottom vent opening, and a generator tube for transmitting a mixture of air and gasoline to said main burner, said tube being threaded at one end and having a discharge orifice at the other end,

a device for adapting said stove for burning liquid petroleum gas fuel comprising:

needle-type shut-off valve means, including a valve housing threadedly connected to the threaded end of said generator tube,

adjustable gas pressure regulating means,

a length of flexible hose connecting said regulator means and said shut-off valve means,

a tank of pressurized liquid petroleum gas fuel,

connector means connecting said regulator means to said tank,

and attaching means including a resilient means connected to said housing and a hook means connected to said resilient means at one end and hooked to an edge of said vent opening for rigidly attaching said generator tube and housing to said stove when said tube is inserted through said access opening and into said fuel inlet openmg.

5. The method of converting a normally gasolineburning camp stove to one for burning liquid petroleum gas fuels, said stove having a base, a main burner in said base including a fuel inlet opening, a front access opening in said base, a gasoline supply tank, a generator assembly connected to said tank including a generator tube, and a needle assembly and coil within said tube,

said method comprising the steps:

removing said gasoline tank from said stove,

removing said generator tube from said tank,

removing said needle assembly and said coil from said generator tube,

inserting said tube through said front access opening and into said fuel inlet opening,

connecting said tube to a supply of pressurized liquid petroleum gas fuel,

controlling the flow of said liquid petroleum gas into said tube by reducing the pressure of the same between said supply and said tube such that the same is discharged from said tube and into said main burner in a gas state.

6. In combination with a gasoline-burning cam-p stove having a burner with a fuel inlet opening, a conversion device for converting said stove for use with liquid petroleum gas fuels,

said device comprising in combination:

an elongate rigid metal tube having a discharge orifice at one end and a threaded opposite end,

said tube having a length sutficient to extend from the front of said stove to said fuel inlet opening,

shut-off valve means including a shut-01f valve housing threadedly connected at its outlet end to the threaded end of said tube,

means On said housing for rigidly and removably attaching said housing to said stove with the discharge orifice end of said tube inserted in said fuel inlet opening,

a length of flexible hose connected at one end to the inlet end of said housing,

pressure-regulating valve means including a regulator housing connected at its outlet end to the other end of said hose,

and threaded coupling means connected to the inlet end of said regulator housing for threadedly connecting said regulator means to a tank of pressurized liquid petroleum gas fuel.

7. In combination with a gasoline-burning camp stove having a burner with a fuel inlet opening, a stove housing having an access opening therein into the interior of said housing, and a fuel-vaporizing tube including a rod and coil within said tube, said tube having an orifice at one end and being threaded at the opposite end thereof,

a device for adapting said gasoline-burning camp stove for burning liquid petroleum gas fuel comprising:

storage means for storing a pressurized supply of liquid petroleum gas fuel,

flexible conduit means extending between said storage means and said fuel-vaporizing tube,

first connector means carried by one end of said flexible conduit means for threadly connecting said one end to said storage means,

second connector means carried by the opposite end of said flexible conduit means for threadedly connecting said opposite end to said fuel-vaporizing tube after said rod and said coil have been removed from said tube,

pressure-reducing valve means connected to said flexible conduit means between said first and second connector means,

flow control and shut-ofi valve means connected to said flexible conduit means between said first and second connector means,

and attaching and stabilizing means for removably connecting said flexible conduit means and its connected elements to said stove housing and for stabilizing said fuel-vaporizing tube in its operative position within said housing.

References Cited by the Examiner UNITED STATES PATENTS CHARLES J. MY'HRE, Primary Examiner,

Claims

1. A CONVERSION APPARATUS FOR USE IN COMBINATION WITH A LIQUID-FUEL BURNING STOVE FOR CONVERTING SAID STOVE TO USE WITH LIQUID PETROLEUM GAS FUELS, SAID STOVE NORMALLY INCLUDING A BURNER WITH A FUEL INLET AND A GENERATOR TUBE CONNECTED TO A LIQUID FUEL TANK AND HAVING A ROD AND COIL WITHIN SAID TUBE, SAD APPARATUS COMPRISING: A LENGTH OF FLEXIBLE HOSE, A REDUCTION VALVE MEANS CONNECTED TO ONE END OF SAID HOSE, CONNECTOR MEANS ADAPTED FOR CONNECTING SAID REDUCTION VALVE MEANS TO A PRESSURIZED SUPPLY OF LIQUID PETROLEUM GAS FEUL, A SHUT-OFF VALVE MEANS CONNECTED TO THE OTHER END OF SAID HOSE, SAID SHUT-OFF VALVE MEANS INCLUDING A HOUSING PROVIDED WITH A CONNECTOR MEANS ADAPTED FOR CONNECTING SAID HOUSING TO THE GENERATOR TUBE OF THE LIQUID-FUEL BURNING STOVE AFTER THE TUBE HAS BEEN DISCONNECTED FROM