INSULATED BURNER SYSTEM FOR GAS-FUELED LIGHTERS

Abstract

A burner assembly for gas-fueled lighters includes a metallic burn chamber rigidly connected to a fuel metering valve. The burner and fuel valve are rigidly connected through an insulated coupling component. This provides a more reliable structure and reduces heat transfer from the burner to the fuel source, reducing vapor lock conditions.

Description

FIELD OF THE INVENTION

The present invention relates generally to flame generating pocket lighters, and specifically to gas-fueled pocket lighters.

DESCRIPTION OF THE PRIOR ART

There are two primary types of gas-fueled pocket lighters presently available. The first type of gas-fueled lighter devices utilizes a post-mix burner for the creation and support of the flame. The gas is delivered through the burner which draws the oxygen for combustion from the surrounding ambient air for combustion. This combustion type is characterized by a low velocity, low temperature yellow flame sometimes referred to as a traditional or lazy flame.

A second type of gas-fueled lighter device incorporates a pre-mix burner. This type of burner draws ambient air through holes provided in the base of the burner and combines the necessary oxygen from the air with the gas fuel prior to combustion. This combustion type is characterized by a high velocity, blue flame. Lighters which utilize pre-mix burners produce significantly higher flame temperatures than that which utilize post-mix burners because of more efficient combustion. The devices are commonly referred to as blue flame, torch flame, or invisible flame lighting devices. The pre-mix lighter burners burn at a higher heat and velocity makes the flame more stable and less likely to be blown out by wind or other ambient conditions.

Two primary ignition systems are typically used in conjunction with gas-fueled cigarette or pocket lighters. The first type is the flint and wheel ignition mechanism. A hardened striking wheel is rotated against a flint made of a pyrophoric material. The functional engagement of the striking wheel with the flint produces a spark which is directed at and ignites the fuel as it leaves the gas outlet. Another type of ignition system is piezoelectric. In this type of ignition system, a high voltage charge is generated when a crystal is struck. A spark is created when this charge jumps across a preset gap between an electrical contact and the gas nozzle, which is constructed of a conductive material. This spark ignites the gas as it leaves the nozzle. The flint and wheel type ignition system offers some advantages over piezoelectric ignition systems, including being more reliable and consistent and less costly to produce.

The higher flame temperatures produced by pre-mix burners require a method of insulating the rest of the lighter from the high heat generated during combustion to prevent damage to the internal burner and gas supply valve components or ignition of its contents. More commonly, the conducted heat will cause the liquid fuel to boil around the gas supply valve resulting in what is termed “vapor lock.” Vapor lock occurs when the liquid fuel changes state from liquid to gas around or near the fuel metering valve. This disrupts the operation of the fuel system and may cause loss of fuel feed pressure to the burner. The fuel can vaporize because of excess heat transferred from the burner. Vapor lock can cause reduced flame height and flame extinction.

One traditional method for preventing damage to pocket lighter components caused by heat transfer from the flame is the use of a ceramic insulating burn chamber. The ceramic chamber surrounds the base of the flame and is directly connected to a mixing valve and metering valve assembly which supply the gas fuel. Ceramics are poor heat conductors and thus good insulators. Ceramic materials may become quite hot during operation of the pre-mix burner, but transfer of this heat is reduced because of the poor heat conduction. Many ceramic materials are also lightweight and are useful in the manufacture of pocket lighters. Ceramic has many shortcomings, however, in that it is a brittle material and is prone to fracture when subjected to sudden impact. The ceramic insulator therefore does not protect the other lighter components located near the flame.

In addition, some prior art designs join the burn chamber and fuel metering valve with plastic tubing for the supply fuel. The plastic material of the tubing is intended to act as an insulator, stopping the conduction of heat into the fuel supply. A disadvantage of this design, however, is that the burn chamber and mixing valve are not rigidly connected to the fuel metering valve. This non-rigid connection between the critical components of the fuel supply system increases the chances for the burner assembly to become disconnected from the gas metering valve during use or transportation of the lighter, which in turn causes an interruption in the supply of fuel to the site of combustion. A burner assembly that is directly and rigidly connected to the fuel metering valve ensures that the supply of fuel to the combustion site will be uninterrupted.

FIG. 1 is an enlarged sectional view of a prior art burner assembly 6. The components of burner assembly 6 include insulating chamber 7, coupler 8, air intake port 10 and body 11. FIG. 2 is a detail section view of FIG. 1 illustrating commonly used components in the prior art burner assembly designs. Insulating chamber 7 is typically constructed of a ceramic material. As discussed above, this insulating chamber 7 is therefore prone to fracture when subjected to sudden impact. Referring now to FIGS. 1 and 2 Coupler 8 requires one or more O-rings 14, washers 13 and gas orifice disks 12 to join the interface between the coupler 8 and body 11. One of skill in the art will readily appreciate that burner assembly 6 may not be directly and rigidly connected to an upstream gas delivery source at coupler 8 and that coupler 8 does not provide thermal insulting properties. This may result in the interruption of the supply of fuel to the site of combustion. What is lacking in the art, therefore is a burner assembly which permits the rigid mounting and interconnection between the burner and the upstream gas delivery components, which also insulates the heat transfer therefrom.

SUMMARY OF THE INVENTION

The present invention avoids the shortcomings of the fragile ceramic insulating materials and the conditions resulting from the conduction of heat into the lighter fuel reservoir. Though the use of a solid insulator and a metallic born chamber. Prior pocket lighter designs utilized plastic tubing as an insulator to join the burner assembly and fuel metering valve. This non-rigid connection increases the chances of the lighter components becoming disconnected or damaged. The use of rubber tubing also requires a separate gas orifice disk to seal the connection. This gas orifice disk requires one or more additional compression washers and sealing O-rings to insure the integrity of the seal. The present invention utilizes a design consisting of a insulating rigid connection between the burner assembly and the fuel metering valve which greatly reduces the conduction of heat into the fuel reservoir. The burner coupling component that connects the burner assembly to the fuel metering valve is composed of a high temperature, stable and insulting material, preferably a material such as thermoset plastic or very high temperature resistant thermoplastic. One example of such a material is polyetherimide, manufactured by Saudi Basic Industries Corp, Saudi Arabia under the trade name Ultem®. Another option would be a phenolic plastic. The use of high temperature resistant plastic allows for containment of heat within the burner assembly, thus insulating the fuel reservoir from heat generated from fuel combustion. In addition, the design of the coupling component eliminates the need for separate components used to seal the interface between the burner assembly and the fuel metering valve. The presently described coupling component makes the use of a separate gas orifice disk, compression washer, and sealing O-ring unnecessary because the gas orifice is integrated into the coupling component. This eliminates the chance for O-ring failure resulting from exposure to high temperatures, simplifies the assembly process and reduces cost.

Thermo-insulating ceramic chambers are traditionally incorporated into gas fueled pocket lighters to prevent migration of heat from the flame to the fuel supply. Ceramics are generally light materials and are good heat insulators. However, ceramic materials are fragile and susceptible to breaking or chipping when subjected to sudden force and therefore do not adequately protect the lighter components from forces observed in everyday use. The high temperature resistant coupling component of the present invention prevents heat migration from the lighter flame to the fuel supply, thus making the use of a ceramic insulator unnecessary. The improved coupling component allows the use of a metallic burn chamber, preferably constructed of a material such as stainless steel or tungsten, in place of the typical thermo-insulating ceramic. The rigid and impact-resistant metallic burn chamber protects other lighter components adjacent to the flame.

The use of a rigid fuel supply system connection and a more durable burn chamber greatly reduces the chance of failure which may result from a sudden impact, such as being dropped. These and other advantages and features of the disclosed device will be further illustrated with reference to the appended drawings and description.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a prior art burner design.

FIG. 2 is an enlarged partial sectional view depicting components used in a prior art burner design.

FIG. 3 is a sectional side view of a complete lighter assembly containing the burner system of the present invention.

FIG. 4 is a side sectional view of the burner system of the invention coupled with a fuel supply valve.

FIG. 5 is a side sectional view of the burner system of the invention coupled with a fuel supply valve.

FIG. 6 is a side sectional view of the burner system of the present invention.

FIG. 7 is an enlarged side sectional view depicting the coupling component of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to FIG. 3, a lighter 20 according to the present disclosure is illustrated. It is to be understood, however, that other forms of lighters may be used as alternatives to the particular design of lighter 20 shown in FIG. 3, and that the lighter 20 is presented as an example to illustrate aspects of the present disclosure. Indeed, the lighter 20 may be any lighter design that incorporates a burner system as described herein.

Referring again to FIG. 3, lighter 20 consists of fuel reservoir 3, fuel filling valve 4, fuel metering valve 5, and burner assembly 6, all of the conventional design readily apparent to those skilled in the art. Lighter 20 includes a centrally disposed gas fuel passageway 30. Centrally disposed gas fuel passageway 30 is disposed in the center of burner assembly 6 and extends from burner assembly 6 to fuel reservoir 3. Gas fuel passageway 30 is shown in FIG. 3 in a round configuration. It will be evident to those of ordinary skill that other shapes for the burner assembly may also be suitable such as square, rectangular, and the like.

Gas fuel passageway 30 is in fluid communication with a valved fuel reservoir 3 that typically contains a combustible fuel such as butane or a similar combustible fuel under pressure to keep the fuel in the liquid phase in the reservoir. The operation of fuel reservoir 3 will be evident to those of ordinary skill in the art and therefore is not discussed in detail herein. Because many fuels employed for use in lighters, such as butane, are volatile, the liquid fuel turns to flammable vapor with a drop in pressure when exiting fuel reservoir 3. The lighter has a fuel metering valve 5 that meters the butane gas as it escapes. The gaseous fuel travels through fuel metering valve 5 and gas fuel passageway 30. Flint 2 and hardened striking wheel 1 comprise the igniter system, which may be of the type disclosed in Pfeil, U.S. Pat. No. 6,247,920, issued Jun. 19, 2001, the entire contents of which are incorporated by reference. This igniter system is used to ignite the gaseous fuel as it exits the gas fuel passageway 30 through outlet 26. Burner assembly 6 is mounted such that outlet 26 of gas fuel passageway 30 is disposed in operative relation to the flint 2 such that sparks from flint 2 are capable of igniting the gas as it exits gas fuel passageway 30 through outlet 26. Alternative methods for spark generation for igniting the fuel may be considered and employed, such as a piezo-electric system, as described above.

Referring now to FIGS. 4 and 5, in one implementation of the present disclosure, burner assembly 6 is fluidly connected to nozzle 9 of fuel metering valve 5 through coupler 18. Coupler 18 is constructed of a high temperature resistant and insulting material, for instance a thermoset plastic or a very high temperature resistant thermoplastic, such as Ultem®. As a result, heat produced by the high temperature premix or blue flame is contained within burn chamber 16, as discussed below, and fuel reservoir 3 is insulated from this heat generated from fuel combustion. This decrease in heat retention and transfer decreases the amount of heat conducted into the fuel reservoir. This in turn decreases the opportunity for a vapor lock condition to occur. Burner assembly 6 is directly and rigidly connected to fuel metering valve 5, providing enhanced and continuous fuel supply to the combustion site. FIG. 5 is a sectional view of FIG. 4 taken along line A-A, showing the detail of the components utilized in the assembly of burner assembly 6 with air intake port 10 for fuel mixing and fuel metering valve 5.

In addition, burn chamber 16 is disposed in connection to burner assembly 6. Burn chamber 16 is constructed of a material, such as stainless steel, in place of the thermo-insulating ceramic materials of the prior art. One of skill in the art would recognize that the burn chamber may be constructed with any heat resistant metal. Metallic burn chamber 16 protects components adjacent to the flame from the heat of the premix flame. The metallic burn chamber 16 is also stronger and more resistant to outside forces than prior art ceramic materials, thus shielding other components from damage due to sudden impact, such as being dropped.

The configuration as illustrated in FIGS. 4 and 5 allows for a direct connection of burner assembly 6 and burn chamber 16 to fuel metering valve 5 by coupler 18. Unlike prior art configurations, which use plastic tubing, coupler 18 provides a rigid and stable connection and thus decreases the probability of burner assembly 6 becoming disconnected from fuel metering valve 5. The use of coupler 18, constructed from a high temperatures resistant stable insulating material, also reduces the conduction of heat into fuel reservoir 3. Coupler 18 allows the use of metallic burn chamber 16 in place of ceramic insulating chamber 7, providing increased protection of the lighter components.

Burner assembly 6 has at least one air intake port 10 in fluid communication with gas fuel passageway 30. During operation of lighter 20, fuel is delivered through gas fuel passageway 30, air from the ambient air environment enters air intake port 10 where it mixes with the fuel in gas fuel passageway 30, after which it passes through outlet 26 to burner assembly 6. When ignited, the air and fuel mixture exiting burner assembly 6 combusts with a blue flame pattern.

FIGS. 6 and 7 illustrate enlarged sectional views of the burner assembly of the present invention. This view shows burner assembly 6 with modified coupler 18 inserted therein. Coupler 18 may frictionally or threadably fit within a receptacle formed in body 11 and frictionally or threadably connected to the fuel metering valve 5. Modified coupler 18 has an integrated gas orifice 24 which eliminates the need for a separate gas orifice disk 12, O-ring 14 or washer 13 as used by the prior art and illustrated in FIGS. 4 and 5. Integration of conically shaped gas orifice 24 into modified coupler 18 reduces the need for an O-ring and the associated chance of O-ring failure because of exposure to high temperature or excessive use. The use of integrated gas orifice 24, which is preferably centrally axially located within modified coupler 18, also reduces the number of components necessary for the construction of lighter 20 and a reduction of assembly costs. The high temperature resistant and insulting material of modified coupler 18 also creates an insulating barrier to reduce the conduction of heat into the fuel metering valve 5 through the nozzle 9, as shown in FIGS. 2 and 3.

In practice, a user may initiate a flame by actuating the lighter with a digit to induce fluid flow from fuel reservoir 3 to and through fuel metering valve 5 and gas fuel passageway 30. As used herein, the term “fluid” refers to fluid in a gaseous state, liquid state, plasma state, or combinations thereof. The fuel may travel through a gas flow regulator 22 before entering gas fuel passageway 30. Such a system is describe in detail in McDonough et al., U.S. Patent Application Publication No. 2007/0089488, published Oct. 13, 2006, the entire contents of which are incorporated herein by reference, and may include a series of valves and flow restrictors. The fuel travels through metering valve 5 which is rigidly connected to burner assembly 6. The fuel is mixed with ambient air entering through air intake port 10 which is in fluid communication with gas fuel passageway 30. The fuel then exits gas fuel passageway 30 through outlet 26 and into burner assembly 6. The fuel is ignited with an ignition system which is also similarly activated by the user's digit. The resulting pre-mix blue flame is generated and exhibits higher heat and stability.

While the invention has been described in connection with certain embodiments, it is not intended to limit the scope of the invention to the particular forms set forth, but, on the contrary, it is intended to cover such alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.

Claims

1.-17. (canceled)

18. A combustible fuel burner system comprising:

a fuel metering valve (5) including a gas flow regulator (22) and a nozzle (9);

a burner assembly (6) including a body (11) and a metal burn chamber (16) directly mounted to the body (11); and

a coupler (18) extending from the nozzle (9) of the fuel metering valve (5) to the burner assembly (6), wherein the coupler (18) is composed of a high temperature resistant and insulating material and the coupler (18) directly and rigidly connects the burner assembly (6) to the fuel metering valve (5);

the nozzle (9), the coupler (18), and the burner assembly (6) defining a gas fuel passageway (30) directing flow sequentially through the nozzle (9), the coupler (18), and the body (11) to the burn chamber (16), and the body (11) including an air intake port (10) communicating with the gas fuel passageway (30).

19. The fuel burner system according to claim 18, wherein the coupler (18) includes a conically shaped integrated gas orifice (24), wherein an inner wall of the gas orifice (24) converges in a direction of flow from the coupler (18) toward the burn chamber (16).

20. The fuel burner system according to claim 19, wherein the high temperature resistant and insulating material is a thermoplastic.

21. The fuel burner system according to claim 20, wherein the thermoplastic is polyetherimide.

22. The fuel burner system according to claim 19, wherein the high temperature resistant and insulating material is a thermoset plastic.

23. The fuel burner system according to claim 22, wherein the thermoset plastic is phenolic plastic.

24. The fuel burner system according to claim 18, wherein an end face of the coupler (18) directly faces an inner radial step surface of the body (11) without intervening structure.

25. The fuel burner system according to claim 24, wherein the end face of the coupler (18) contacts the inner radial step surface of the body (11).

26. A combustible fuel burner system comprising:

a fuel reservoir (3);

a gas flow regulator (22) communicating with the fuel reservoir (3);

a subassembly operable to receive gas flow from the gas flow regulator (22), the subassembly including a nozzle (9), a coupler (18) directly attached to the nozzle (9), a body (11) directly attached to the coupler (18), and a gas fuel passageway (30) directing flow sequentially through the nozzle (9), the coupler (18), and the body (11); and

a metal burn chamber (16) directly mounted to the body (11);

wherein the coupler (18) is formed of a rigid, high temperature resistant and insulating material;

whereby the coupler (18) reduces conduction of heat from the burn chamber (16) into the fuel reservoir (3) to avoid vapor lock in the fuel reservoir (3) while rigidly and directly coupling the nozzle (9) with the body (11).

27. The fuel burner system according to claim 26, wherein the coupler (18) includes a conically shaped integrated gas orifice (24), wherein an inner wall of the gas orifice (24) converges in a direction of flow from the coupler (18) toward the burn chamber (16).

28. The fuel burner system according to claim 27, wherein the high temperature resistant and insulating material is a thermoplastic.

29. The fuel burner system according to claim 28, wherein the thermoplastic is polyetherimide.

30. The fuel burner system according to claim 27, wherein the high temperature resistant and insulating material is a thermoset plastic.

31. The fuel burner system according to claim 30, wherein the thermoset plastic is phenolic plastic.

32. The fuel burner system according to claim 26, wherein an end face of the coupler (18) directly faces an inner radial step surface of the body (11) without intervening structure.

33. The fuel burner system according to claim 32, wherein the end face of the coupler (18) contacts the inner radial step surface of the body (11).