US3749077A

US3749077A - Vapor generator

Info

Publication number: US3749077A
Application number: US00192028A
Authority: US
Inventors: J Cross
Original assignee: NONI CORP
Current assignee: NONI CORP
Priority date: 1971-10-26
Filing date: 1971-10-26
Publication date: 1973-07-31
Anticipated expiration: 1990-07-31

Abstract

A vapor generator for supplying fuel in its vapor phase only to portable cooking, heating, lighting and other apparatus and devices which heretofore have utilized ignited liquid fuels in their operations. The generator comprises a combination liquid fuel and vapor containing housing, generally annular in form and elliptical in vertical cross section, from which the efflux is confined to fuel in its vapor phase only. Heating means applied to the generator maintain the liquid fuel at vaporizing temperatures, and ignitable contact between the liquid fuel and the heating means is prevented. The housing has a vapor outlet for conveying vapor for utilization in cooking or lighting means which are parts of the generator construction or for utilization in separate devices such as radiant heaters and the like.

Description

United States Patent 1 Cross [11] 3,749,077 [451 Jul 31,1973

[ VAPOR GENERATOR 211 App]. No.: 192,028

Primary ExaminerWilliam F. ODea Assistant Examiner1-1arold Joyce Attorney-Bertha L. MacGregor 57 ABSTRACT A vapor generator for supplying fuel in its vapor phase only to portable cooking, heating, lighting and other apparatus and devices which heretofore have utilized ignited liquid fuels in their operations. The generator comprises a combination liquid fuel and vapor containing housing, generally annular in form and elliptical in vertical cross section, from which the efi'lux is confined to fuel in its vapor phase only. Heating means applied to the generator maintain the liquid fuel at vaporizing temperatures, and ignitable contact between the liquid fuel and the heating means is prevented. The housing has a vapor outlet for conveying vapor for utilization in cooking or lighting means which are parts of the generator construction or for utilization in separate devices such as radiant heaters and the like.

PATENIED JUL3 1 ms 3, 749 i 077 Sam 1 or 4 21?? INVENTOR. JOHN E CR ATTORNEY PATENIEBJum I973 $749,077

sum 2 0F 4 llllll 11122221122! ZF INVENTOR.

awn-5 JOHN F CROSS BY was ATTORNEY PATENlEoJuLa 1 I973 sum 3 0 4 1 III! INVENTOR. JOHN E CROSS ATTORNEY PATENIEDJUL31 ma SHEET 8 0F 3 ATTORNEY 1 VAPOR GENERATOR This invention relates to a vapor generator for supplying fuel in its vapor phase only to portable cooking, heating, lighting and power apparatus and devices which heretofore have utilized ignited liquid fuels in their operations.

The main object of this invention is to provide a vapor generator comprising a heated fuel container from which the efflux is confined to fuel in its vapor phase only. In some embodiments of the invention, the passage of liquid fuel out of the generator housing to a burner which is part of the embodiment is prevented by structural means in the container which confine the liquid fuel but permit passage of vapor only to the burner; in other embodiments the liquid fuel container of the generator also confines the liquid but has a vapor outlet located in the top wall for passage of vapor to other devices and apparatus which utilize ignitable vapor as their fuel.

Prior art devices utilizing ignited liquid fuels comprise a fuel container wherein the fuel is discharged in liquid state by gravity, manual or heat pressurization, or by capillary action of a wick. These devices are subject to operational limitations and require specially prepared fuels. The utilization of a fuel container as a vapor generator according to my invention results in improved operation and adaptation of the construction to a wide range of readily available fuels. Common fuels are available for internal combustion engines and are blends of a reasonably wide temperature distillation range, containing additives which improve performance for their intended applications. However, the use of these fuels in devices as ignitable heat sources, involving flame ignition under natural atmospheric conditions, is detrimental when such common fuels leave the container as a liquid composite of various distillation fractions and containing additives intended for other applications. Related to which, the additives are concentrated in the capillaries. ln pressurized devices, vaporization takes place in the metering value due to pressure reduction across the valve and the additives are concentrated in valve and orifice parts, causing malfunction.

In accordance with the invention herein disclosed, as applied to portable heating devices, the liquid fuel is distilled in the fuel container and additives of the fuel remain in the residue liquid, which can be discarded.

When initiating operation, the lower temperature fractions of the fuel composites are first vaporized, permitting an earlier stablization of operation and flame characteristics than when the liquid fuel is metered as a composite liquid in prior art devices. As the operation of the vapor generating unit continues, sufficiently higher vaporization temperatures are available to insure complete practical use of the fuel, thus extending adaptation to a wider range of fuels. During operation of devices utilizing the principle of the invention, the distillation process concentrates the additives and heavy end fractions as residue liquid which may be discarded before refilling the container.

Due to the lower density of vapor in respect to liquid fuel, the volumetric consequence permits larger orifice metering, and that allows more precise control in small energy devices, as well as higher adaptability of orifices for metering liquid at gravity pressure, initially at cold start, with compatability of the same orificing for me tering vapors under pressure head developed from heating.

Another benefit gained by application of the inventive principle to self-pressurizing heat devices is the minimizing of pressure build-up as a result of metering lower density vapors rather than the higher density liquid fuel, causing a higher volume efflux minimizing the lower temperature volatiles first during initial operation at lower temperature and allowing the higher temperature volatiles to remain to be volatilized under higher temperatures as operation continues, resulting in alleviating the pressure increment with temperature during sustained operation.

Another object of the invention is to provide a combination fuel container and vapor generating housing elliptical in cross section, in which all surfaces are curved as most ideal for strength of the housing, and, further, to enhance the passage of air in a smooth laminar flow to afford maximum amount of heat removal from the external surfaces of the inner peripheral wall of the vaporizing-liquid container, as well as to provide a convergent-divergent passage for thermal syphon air to enhance the maximum amount of air passing through the interior of the housing. The elliptical cross section design affords a maximum compromise between proximate and convection heat loss to minimize temperature build-up and subsequent vapor pressure in the liquid container. The elliptical shape further provides a minimum exposure by geometry at its apex for radiant heat transfer from the flame capsule as it is deflected outward by heating utensils over the vaporizing fuel container when the invention is embodied in a cooking stove.

In some embodiments of the invention, a small quantity of the liquid fuel in the vapor-producing container is utilized for heating the container contents to thereby initiate the vaporization process. For example, in a selfcontained cooking stove in which the liquid fuel containing housing constitutes the body of the stove, a restricted volume of liquid fuel passes to an auxiliary chamber into communication with a metering valve which permits passage of the liquid fuel to a burner orifree in an air mixing chamber where it is ignited and functions to heat the fuel container to initiate the vapor producing process. After the estricted amount of liquid fuel in the auxiliary chamber has been consumed for the purpose stated, the supply cannot be replenished while the vaporizing process continues. Thereafter, only fuel in the vapor phase can pass into the auxiliary chamber for passage to the cooking stove burner, where it functions to maintain vaporizing temperatures in the container housing, as well as to heat the contents of cooking utensils supported on the stove.

ln self-contained lighting apparatus, such as an incandescent mantle equipped lantern, the initiation of the vaporizing process is performed as it is in the cooking stove embodiment of the invention, by allowing a small volume of liquid fuel to pass into an auxiliary chamber for passage to a burner orifice, resulting in heating of the liquid fuel in the container for converting the liquid fuel to vapor. Means are provided for conducting unignited vapor to the lighting apparatus after the vaporiza tion process has been initiated, which requires a very short time, usually less than a minute.

In apparatus where the vapor is to be utilized for heating purposes, such as barbecue cookers, toasters, rotisseries and radiant heaters, in which the vapor generator is not a built-in part, the initial heating of the liquid fuel container of the generator may be performed by the use of a restricted amount of liquid fuel, in an auxiliary chamber, followed by conducting vapor out of the generator to the heating apparatus. In this embodiment of the invention, the liquid fuel burner has low capacity, i.e., only sufficient to maintain the heat required for vaporizing the liquid fuel in the generator. The heating means for maintaing the vaporizing temperature may be electrical, thus making it possible to dispense with the use ofliquid fuel for initiating the vapor generating process.

The several embodiments referred to hereinabove as well as the generator, per se, are shown in the drawings.

In the drawings:

FIG. 1 is a vertical sectional view of a vapor generator embodying my invention, adapted to convey vaporized fuel to other devices for cooking, roasting, radiant heating, and/or lighting.

FIG. 2 is a top view of the vapor generator embodied in a cooking stove.

FIG. 3 is a horizontal sectional view of the device shown in FIG. 2.

FIG. 4 is a vertical sectional view in the plane of the line 4-4 of FIG. 3.

FIG. 5 is a fragmentary sectional view of a modification of the generator shown in FIGS. 2-4.

FIG. 6 is a longitudinal sectional view of the metering valve which is part of the cooking stove and some other embodiments of the invention shown herein.

FIG. 7 is an elevational side view ofa vapor operated barbecue, rotisserie and radiant heater designed to receive and ignite vaporized fuel from the generator shown in FIG. 1.

FIG. 8 is a vertical sectional view of the vapor operated device of FIG. 7, in the planes of the line 88 of FIG. 7.

FIG. 9 is a vertical sectional view ofa self generating vapor lantern embodying the invention.

FIG. 10 is a vertical sectional view of an electrically operated and controlled vapor generator adapted to convey vaporized fuel to other devices such as described herein.

FIGS. 1 and 4 show vertical sectional views of vapor generators which embody similar housings each comprising a combination liquid fuel holder and vaporizing container, but differ in that the generator of FIG. 1 is designed to convey vaporized fuel to other devices whereas the generator of FIGS. 2-4 is part ofa cooking stove in which the generated vapor is utilized for burning. The sectional view shown in FIG. 3 is applicable also to the generator of FIG. 1 with respect to the construction of the similar housings which comprise the combination fuel container and fuel vaporizing means.

Referring to FIGS. 1 and 3, the generally annular housing which functions as a fuel container and vapor generator is elliptical in vertical section and preferably made of cast metal. The outer peripheral wall 21 of the housing is thickened in spaced apart areas as shown in FIG. 3 to facilitate the production processes and to provide a threaded fuel intake 22 closed by a threaded closure member 23. The inner peripheral wall 24 of the housing conforms generally to the shape of the outer peripheral 'wall 21 which is non-concentric with respect to the axial center of the housing 20. The

walls

21 and 24 enclose a chamber 25 elliptical in vertical cross section, except as noted hereinafter, and continuous in horizontal cross section as shown in FIG. 3.

The elliptical vertical cross sectional shape of the chamber 25 is interrupted by the metering rod 26 which extends in radial direction beneath the chamber 25 just above the bottom of the housing 20 from the metering valve 27 shown diagrammatically in FIGS. 1, 3 and 4.

The internal contour of the elliptical chamber 25 also is altered in one section, opposite the intake opening 22, by a vertical partition 28 spaced from the peripheral inner wall 24 and connected thereto by side partition walls 29. The partition 28 is shorter than the height of the chamber 25, leaving a gap 30 between the upper edges of the

partition

28, 29, and the top of the chamber. The space between the

partition

28, 29, and the inner wall 24 provides an auxiliary chamber 31 communicating with the metering valve 27 through the passageway 32. Feet 33 support the housing 20 as a whole.

The generator of FIG. 1, designed to generate vapor to be utilized in other devices, is equipped with a burner 35 located in an air-vapor mixing chamber 36 in the space between the peripheral inner walls 24 of the housing 20. The burner 35 receives vapor from the metering valve 27. The burner is restricted to capacity sufficient only to maintain vaporization of fuel in the chamber 25 to supply required vapor to the other devices. The vapor generated by the described apparatus (except that consumed by the burner 35) passes from the chamber 25 through the conduit 37 to the device to be supplied with vapor for cooking, roasting, radiant heating or other uses.

The generator of FIGS. 2-5, embodied in a cooking stove, embodies the previously described parts 20-33 inclusive. The structural features of the combination cooking stove and vapor generator include a cup shaped air-vapor mixing member 40, with upper deflector plate 41, and burner 42 in the mixing member in communication with the metering valve 27. For cooking purposes, the housing 20 is provided on its upper surface with three supports 43 which have a flat top surface 44 for supporting large cooking utensils (not shown) and a lower flat shoulder surface 45 for smaller containers (not shown) which fit between the supports 44.

The modification shown in FIG. 5 differs from the FIGS. 1-4 construction in the contour of the partition 28 and the shape of the housing walls 21', 24 and chamber 31.

The operation of the vapor generators of FIGS. 1-5 is as follows: The closure member 23 is removed, the housing 20 is tilted to axially horizontal position, with the intake opening 22 at the top, and fuel is poured through the opening 22 into the chamber 25. Part of the fuel passes through the gap 30 into the auxiliary chamber 31. Then the housing is restored to its normal horizontal position in which the axis of the generator is vertical. The burner 35 (FIG. I) or 42 (FIG. 4) is ignited. The fuel in the auxiliary chamber 31 is consumed by the burner flame and cannot be replenished while the generator is in that operative position, but within a very short time, usually less than a minute, the heat produced by the flame heats the fuel in chamber 25 and generates pressure in the fuel chamber 25 resulting in generating of vapor which passes from the chamber 25. In the generator of FIG. 1, the vapor passes from the combination fuel container and vaporizer chamber 25 in two streams; first, through the gap 30 to the auxiliary chamber 31 for passage to the burner 35 which has restricted capacity for maintaining vaporization of fuel in chamber 25, and, secondly, through the conduit 37 to a device such as a barbecue, rotisserie or radiant heater or other vapor operated appliance. In the generator of FIGS. 2-5, the vapor passes from the combination fuel container and vaporizer chamber through the gap to the burner 42 for two purposes, namely, to provide heat to maintain the vaporization of fuel in chamber 25, and also to heat cooking utensils supported on the

surfaces

44 or 45 of supports 43.

The valve 27, shown diagrammatically in FIGS. 1, 3 and 4, is shown in detail in FIG. 6. It comprises a cylindrical housing 50, reduced-diameter threaded end 51, threaded outlet 52 communicating with the burner of the generator of FIG. 1 or burner 42 of the cooking stove of FIGS. 25, and open end 53 for mounting of the operating rod 26 of the metering valve. The rod 26 has an inner end 54 internally bored and threaded to engage the threaded end of a conical valve stem 55 which is flattened at 56 for engagement by the pin 57, whereby rotation of the valve stem is prevented while the operating rod 26 is rotated to adjust the longitudinal position of the conical end of the stem 55 relatively to the cylindrical housing end 51. The limiting of movement of the conical metering stem to non-rotative movement prevents wear of the stern.

FIGS. 7 and 8 illustrate a vapor operated barbecue, rotisserie and radiant heater 60 to which fuel vapor is conveyed from the vapor generator of FIG. 1 through the conduit 37. The apparatus 60 comprises a frame 61 provided with slots 62 for grill supports, wind screen 63, cover plate 64, porous refractory lining 65, porous light weight refractory brick 66, distribution plate 67, distribution manifold 68 and hose 69 leading to the vapor generator conduit 37. The details of the heating apparatus of FIGS. 7 and 8 are immaterial; said apparatus being shown merely to illustrate applications of the vapor generator to separate devices.

FIG. 9 illustrates an application of the vapor generator to a lantern 70. The generator resembles the one shown in FIGS. 2-5 built into a cooking stove. The housing 20 and parts designated 21-33 have been described heretofore. The lantern 70 comprises the aforesaid vapor generator and lantern parts such as the transparent side walls 71 mounted in a groove formed in the top of the generator housing 20, top shield 72 circumferentially engaging the side walls 71, threaded bolt 73 and nut 74, with ring 75, the bolt extending through the cover shield 72 to tie the ring and nut to the lighting means within the lantern housing. Said lighting means comprises an air-vapor mixing chamber casing 76 surrounding a burner 77 and extending upwardly to form a cylindrical casing 78 for conducting vapor to lines 79 leading to a pair of incandescent mantles 80.

In this application of the invention, burning takes place at the vapor orifice 77 to initiate sufficient heat to cause vaporization. Thereafter, vapors are admitted through the vapor orifice 77, mixed with air in the mixing chamber 78, and subsequent ignition takes place on the surface of mantle 80, to cause incandescence. The radiant energy from mantles 80, in close proximity to the fuel container 21, maintains sufficient heating of the container to sustain vaporization of the liquid fuel.

FIG. 10 shows a modification of the generator of FIG. 1. The modified structure is electrically operated and controlled. Since the burning of liquid fuel at the initiation of the vaporizing process in the generators of the previously described constructions is not required in the electrically operated and controlled mechanism of FIG. 10, the auxiliary chamber 31 and burner 35 have been eliminated in this modification. The housing 20, comprising

walls

21 and 24 which define the elliptical chamber 25 for containing fuel and generating vapor therein, together with the vapor conveying conduit 37, are designated as heretofore described. The passage 32 is closed by a bolt 38.

In FIG. 10, the means for heating fuel in the chamber 25 to initiate and maintain the vapor generating process is a Calrod type immersion heater inserted into the chamber 25 at one side through an opening in the housing wall 21. The outer end of the heater 90 extends through a threaded bearing 91 and nut 92, with wiring 93 leading to the control box 94. The wiring 95 conducts current from a l 10 volt electrical supply. The control box contains a switch 96, switch operating lever 97, fixed on rod 98, strip thermostat 99, and thermostat adjustment cam 100. An off-on range selection knob 101 is mounted on the outer end of the rod 98.

In all embodiments of the invention, the salient novel feature is the generating of vapor by unignited liquid fuel arid utilization of the vapor in apparatus or devices of which the generator is a part or in separate devices or apparatus that receive the vapor from the generator.

I claim:

1. A vapor generator supplying fuel in its vapor phase only to cooking, heating, lighting and other apparatus comprising a. a liquid fuel containing housing in which the fuel is converted to vapor,

b. a burner maintaining the fuel in the housing at vaporizing temperatures,

0. means preventing ignitable contact between the liquid fuel and the burner,

d. a vapor outlet in said housing conveying vapor to the burner, and

e. a vapor outlet at the top of said housing conveying vapor to separate vapor-utilization means,

said means preventing ignitable contact between the liquid fuel and the burner comprising a partition dividing the interior of the housing into a main liquid fuel and vapor chamber and a smaller auxiliary chamber communicating with each other by a restricted gap at the top of the partition, said gap allowing a restricted volume of liquid fuel to pass into the auxiliary chamber when the housing is in horizontally axial position and said partition preventing passage of liquid fuel when the housing is in its operative horizontal position wherein the axis is vertical, whereby the restricted volume of liquid fuel can pass from the auxiliary chamber to the burner and serves when ignited to initiate generating of vapor and when consumed cannot be replenished while the generator is in operative position, and only vapor can pass from the generator through the auxiliary chamber to the burner.

2. The vapor generator defined by claim 1 that supplies vapor to vapor-utilizing apparatus separate from the generator, and which includes a hose detachably connected to the vapor outlet at the top of said housing and to said separate vapor-utilizing apparatus.

3. A vapor generator supplying fuel in its vapor phase only to cooking apparatus comprising a. a liquid fuel containing housing generally annular in shape in which the fuel is vaporized,

b a burner located in a space between the inner peripheral walls of the annular housing maintaining the fuel at vaporizing temperatures and heating contents of cooking utensils,

c. means in the fuel containing housing preventing ignitable contact between the liquid fuel and the burner, and

d. a vapor conveying valved passageway between the housing and burner,

4. The vapor generator defined by claim 3, in which the housing is provided on its top surface with a plurality of cooking utensil supports having flat surfaces on two different levels supporting utensils of different diameters over the burner.

5. The vapor generator defined by claim 3, in which the housing is elliptical in cross section throughout the major part of its annular form.

6. The vapor generator defined by claim 3, which includes a metering valve located in the passageway between the housing and burner, said metering valve having a rotatable control rod actuating a non-rotatable conical valve stem in longitudinal directions.

7. A vapor generator supplying fuel in its vapor phase only to lighting apparatus embodying an incandescent mantel comprising a. a liquid fuel containing housing generally annular in shape in which fuel is vaporized,

b. a burner adjacent the housing for initiating vaporization of fuel in the housing,

c. means in the fuel containing housing preventing ignitable contact between the fuel and the burner,

d. a vapor outlet in said housing and a passageway conveying vapor from the outlet to the burner,

e. lighting apparatus embodying an incandescent mantle mounted on the fuel containing housing, and

f. a mixing chamber and tubular conduit conveying vapor from the burner orifice to the mantle in the lighting apparatus,

Claims

1. A vapor generator supplying fuel in its vapor phase only to cooking, heating, lighting and other apparatus comprising a. a liquid fuel containing housing in which the fuel is converted to vapor, b. a burner maintaining the fuel in the housing at vaporizing temperatures, c. means preventing ignitable contact between the liquid fuel and the burner, d. a vapor outlet in said housing conveying vapor to the burner, and e. a vapor outlet at the top of said housing conveying vapor to separate vapor-utilization means, said means preventing ignitable contact between the liquid fuel and the burner comprising a partition dividing the interior of the housing into a main liquid fuel and vapor chamber and a smaller auxiliary chamber communicating with each other by a restricted gap at the top of the partition, said gap allowing a restricted volume of liquid fuel to pass into the auxiliary chamber when the housing is in horizontally axial position and said partition preventing passage of liquid fuel when the housing is in its operative horizontal position wherein the axis is vertical, whereby the restricted volume of liquid fuel can pass from the auxiliary chamber to the burner and serves when ignited to initiate generating of vapor and when consumed cannot be replenished while the generator is in operative position, and only vapor can pass from the generator through the auxiliary chamber to the burner.

3. A vapor generator supplying fuel in its vapor phase only to cooking apparatus comprising a. a liquid fuel containing housing generally annular in shape in which the fuel is vaporized, b. a burner located in a space between the inner peripheral walls of the annular housing maintaining the fuel at vaporizing temperatures and heating contents of cooking utensils, c. means in the fuel containing housing preventing ignitable contact between the liquid fuel and the burner, and d. a vapor conveying valved passageway between the housing and burner, said means preventing ignitable contact between the liquid fuel and the burner comprising a partition dividing the interior of the housing into a main liquid fuel and vapor chamber and a smaller auxiliary chamber communicating with each other by a restricted gap at the top of the partition, said gap allowing a restricted volume of liquid fuel to pass into the auxiliary chamber when the housing is in horizontally axial position and said partition preventing passage of liquid fuel when the housing is in its operative horizontal position wherein the axis is vertical, whereby the restricted volume of liquid fuel can pass from the auxiliary chamber to the burner and serves when ignited to initiate generating of vapor and when consumed cannot be replenished while the generator is in operative position, and only vapor can pass from the generator through the auxiliary chamber to the burner.

7. A vapor generator supplying fuel in its vapor phase only to lighting apparatus embodying an incandescent mantel comprising a. a liquid fuel containing housing generally annular in shape in which fuel is vaporized, b. a burner adjacent the housing for initiating vaporization of fuel in the housing, c. means in the fuel containing housing preventing ignitable contact between the fuel and the burner, d. a vapor outlet in said housing and a passageway conveying vapor from the outlet to the burner, e. lighting apparatus embodying an incandescent mantle mounted on the fuel containing housing, and f. a mixing chamber and tubular conduit conveying vapor from the burner orifice to the mantle in the lighting apparatus, said means preventing ignitable contact between the liquid fuel and the burner comprising a partition dividing the interior of the housing into a main liquid fuel and vapor chamber and a smaller auxiliary chamber communicating with each other by a restricted gap at the top of the partition, said gap allowing a restricted volume of liquid fuel to pass into the auxiliary chamber when the housing is in horizontally axial position and said partition preventing passage of liquid fuel when the housing is in its operative horizontal position wherein the axis is vertical, whereby the restricted volume of liquid fuel can pass from the auxiliary chamber to the burner and serves when ignited to initiate generating of vapor and when consumed cannot be replenished while the generator is in operative position, and only vapor can pass from the generator through the auxiliary chamber to the burner.