Note: Descriptions are shown in the official language in which they were submitted.
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THE DESCRIPTION
INSULATED BURNER SYSTEM FOR GAS-FUELED LIGHTERS
TECHNICAL FIELD
The present invention relates generally to flame generating pocket lighters,
and specifically to
gas-fueled pocket lighters.
BACKGROUND 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
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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.
Figure 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. Figure 2 is
a detail section view of Figure 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 Figures 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.
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DISCLOSURE OF 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
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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
Figure 1 is a sectional view of a prior art burner design.
Figure 2 is an enlarged partial sectional view depicting components used in a
prior art burner
design.
Figure 3 is a sectional side view of a complete lighter assembly containing
the burner system
of the present invention.
Figure 4 is a side elevational view of the burner system of the invention
coupled with a fuel
supply valve.
Figure 5 is a side sectional view of the burner system of the invention
coupled with a fuel
supply valve taken along line V-V of Figure 4.
Figure 6 is a side sectional view of the burner system of the present
invention.
Figure 7 is an enlarged side sectional view depicting the coupling component
of the present
invention.
BEST MODE FOR CARRYING OUT THE INVENTION
Referring now to Figure 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 Figure 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 Figure 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
Figure 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
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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, United States Patent No. 6,247,920, issued June 19, 2001, the entire
contents of which are
5 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 Figures 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. Figure 5 is a sectional view of Figure 4 taken along line V-
V, 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 Figures 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
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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.
Figures 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 Figures 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 Figures
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 October 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.
