Patent Application
20140329188
The present invention relates generally to flame generating pocket lighters, and specifically to gas-fueled pocket lighters.
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.
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.
Referring now to
Referring again to
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
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
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.
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.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 12537136 | Aug 2009 | US |
| Child | 14334749 | US |
