Self-igniting portable torch assembly

A self-igniting portable torch includes source of electrical potential mounted on the outside of the torch tip downstream of the orifice in a heat resistant housing and an electrode which extends into the mixing chamber. The source of electrical potential and the electrode are electrically coupled by a connector contained entirely within the torch tip.

BACKGROUND OF THE INVENTION 
The present invention relates to a portable torch assembly, more 
particularly to a self-igniting or instant igniting portable torch 
assembly. 
The concept of having a self-igniting or instant igniting portable torch 
assembly provides a great convenience to the user as it eliminates the 
need for carrying a portable hand-held sparker or a cigarette lighter to 
ignite the pressurized flammable fluid which supports the flame emanating 
from the burner or torch tip of the portable torch assembly. 
Prior art self-igniting or instant igniting portable torch assemblies have 
tended to be complex devices wherein a spark producing electrode is 
extended int the mixing chamber or burn tube of the torch tip. The source 
of electrical energy to produce the spark is typically located away from 
the spark producing electrode. The combined electrode and power source are 
typically called piezoelectric igniters. Herein the mechanical distortion 
of a crystal produces an electrical potential sufficient to produce a 
spark. 
In prior art torch assemblies the remote location of the piezoelectric 
igniter has necessitated complex conducting paths for electrical energy 
from the crystal to the most desirable spark location. The use of complex 
conducting paths raises the cost of producing the torch. Additionally such 
complete conducting paths have made the torches difficult to operate 
because of the inconvenient location of the manual piezoelectric igniter 
activator button. 
There is therefore a need in the art to provide an inexpensive portable 
torch assembly with a simplified conducting path wherein the activator 
button for the piezoelectric igniter is in a convenient location. 
Many prior art torches have run electrical connections between the source 
of electrical potential and the spark producing electrode outside of the 
torch tip This configuration greatly increases the exposure of the 
electrical connections to damage. 
There is therefore an additional need in the art to provide a portable 
torch assembly with protected electrical connections between the 
piezoelectric crystal and the spark producing electrode. 
Exemplary of prior art self igniting torch assemblies are the following: 
U.S. Pat. No. 3,655,324 to Schweitzer teaches an impact type piezoelectric 
igniter element spring located in a casing with a manual actuator mounted 
around the air hole inlets and electrical connections positioned in an 
unprotected location on the outside of the torch tip. 
U.S. Pat. No. 3,802,828 to Mercer et al. teaches an automatically activated 
piezoelectric crystal type burner igniter whose hammer is driven b 
pressurized fluid. 
U.S. Pat. No. 4,325,356 to Taschler teaches external connections for a 
piezoelectric spark generator for use on a gas fired soldering iron. 
U.S. Pat. No. 4,348,172 to Miller teaches a complex externally connected 
combination piezoelectric igniter and control valve. The manual activator 
button is co-located with the valve which is mounted to the container of 
combustible fluid upstream from the orifice. 
U.S. Pat. No. 4,526,532 to Nelson teaches an externally connected 
piezoelectric igniter on a torch having an orifice and burner tube which 
are removable with respect to the orifice tube. 
U.S. Pat. No. 4,666,399 to Nelson teaches a torch tip with internally run 
electrical connections and a remotely located piezoelectric activator 
button similar to the configuration found in U.S. Pat. No. 4,348,172 to 
Miller. 
Consequently, there remains a need in the art to provide a self-igniting 
portable torch that has a simplified path for conducting electricity from 
the piezoelectric crystal to the location for the spark; does not employ 
external connections between a piezoelectric igniter and a spark producing 
electrode; and places the activator button for the piezoelectric igniter 
in a convenient location. 
SUMMARY OF THE INVENTION 
The self-igniting portable torch assembly of the present invention 
eliminates external connections between the source of electrical potential 
and the spark producing electrode as well as providing a simplified path 
for the flow of electricity by both mounting the piezoelectric igniter on 
the torch tip and passing the electrical connections for the spark 
producing electrode only through the torch tip assembly. The mounting of 
the piezoelectric igniter downstream from the orifice on the outside of 
the torch tip in a heat resistant housing enables the manual activator 
button for the piezoelectric igniter to be placed in a convenient 
location. Such an arrangement also facilitates the easy replacement of 
torch tip assemblies with torch tip assemblies which allow for different 
flame configurations. This is due to the self contained nature of the 
electrical spark generator system. Since the complete system is attached 
to the tip, there is no worry about re-attaching electrical contact 
improperly while changing tips. 
The self-igniting portable torch assembly of the present invention includes 
a orifice which regulates the flow of pressurized combustible or flammable 
fluid from a fluid source or storage container. The pressurized 
combustible fluid, once having passed through the orifice is mixed with 
air or oxygen. The air or oxygen is then caused to enter the stream of 
pressurized combustible fluid by means of a jet pump which uses the 
velocity of the fluid to draw ambient air or raw oxygen into the torch tip 
assembly. Once the air or oxygen is drawn into the flow of pressurized 
combustible fluid it then passes into a mixing chamber. The mixing chamber 
causes the air or oxygen and the pressurized combustible fluid to form a 
highly volatile mixture. When a spark is introduced into the mixing 
chamber the volatile mixture ignites and a flame is produced. The position 
an shape of the flame is controlled by a flame holder and burn tube at the 
end of the torch tip assembly. 
A piezoelectric igniter is mounted in a heat resistant housing on the torch 
tip assembly downstream from the orifice. The piezoelectric igniter 
generates electrical energy by transforming the motion of a striker, which 
deforms a crystal, into an electrical potential. This piezoelectric 
igniter transmits the electrical potential through an electrical connector 
within the torch tip assembly to the place where the spark may ignite the 
flowing volatile gaseous mixture. When the piezoelectric crystal is 
activated, a spark is produced within the torch tip. The flowing volatile 
gases are ignited by the spark and the resulting flame is stabilized on 
the flame holder portion of the torch tip assembly.

DETAILED DESCRIPTION OF THE EMBODIMENTS 
The self-igniting portable torch assembly 10 of the present invention will 
be explained using the illustrative example of self-contained portable 
propane torch assembly. While the instant invention is explained in 
conjunction with a self-contained portable propane torch assembly, it will 
be understood that the present invention may also be utilized with larger 
welding torches where the source of combustible fluid is not necessarily 
self-contained but is separated from the torch tip. Such torches and 
separable pressurized fluid supplies are commonly used with heavy welding 
equipment. 
As may be seen by reference to FIGS. 1 and 2 a self-contained portable 
propane torch assembly 10 typically consists of the following basic 
elements: a source of pressurized combustible fluid 12, a valve 14 and a 
torch tip assembly 15. Torch tip assembly 15 is typically a tubular member 
placed downstream from source 12 and valve 14. The pressurized fluid, 
herein propane gas, is allowed to exit container 12 when valve 14 is 
opened. Valve 14 controls the flow of pressurized propane through 
connection tube 16 to orifice 18. Connecting tube 16 forms the first part 
of the tubular member in torch tip assembly 15 Orifice 18 is positioned 
with orifice holder 19 and is particularly important as it i orifice 18 
which provides a constant velocity flow of propane or of combustible fluid 
into mixing chamber 24. 
To assist in the burning of propane or the combustible fluid, it is 
necessary that air or oxygen enter torch tip assembly 15. This is 
accomplished in the second portion of the tubular member. The addition of 
air or oxygen normally takes place in mixing chamber 24 downstream from 
orifice 18. Air or oxygen is drawn into torch tip assembly 15 from the 
environment by use of a nozzle jet pump 20 which creates a partial vacuum 
by the nozzle effect on the flowing combustible gas. This partial vacuum 
draws in air or oxygen through intake holes 22. Air or oxygen is then 
combined with the pressurized combustible fluid in mixing chamber 24. In 
welding equipment raw oxygen is obtained from a source of pressurized 
oxygen. The precise size of orifice 18 establishes the correct fluid flow 
velocity so that nozzle jet pump 20 draws in sufficient quantity of air or 
oxygen to support a usable flame. 
Mounted downstream from orifice 18 in housing 62 on the outside of torch 
tip assembly 15 is a igniter assembly 26 for producing a spark. Such 
igniters are typically of the piezoelectric type. The piezoelectric 
igniter used herein is of a standard design similar to that shown in U.S. 
Pat. No. 3,984,738. It includes a housing for the crystal 27 and wire or 
electrical connector 36. 
Connection housing 62 is made from a heat resistant, electrically 
non-conductive plastic or similar material so that the heat generated in 
torch tip assembly 15 will not damage housing 27. As may be best seen by 
reference to FIGS. 2 and 5, connection housing 62 includes an extended 
tubular portion 66 which is of sufficient size to fit tightly around torch 
tip assembly 15. Formed integrally with tubular portion 66 is igniter 
containing portion 68. Wall 70 separates tubular portion 66 and igniter 
containing portion 68. The thickness of wall 70 prevent the heat generated 
within torch tip assembly 15 from damaging housing 27, prevents the 
piezoelectric igniter from shorting out and assists in positioning the 
igniter s that it does not disrupt the flow of flammable fluid. One end 72 
of igniter containing portion 68 is open so that manual button 28 is 
positioned for easy access by the user. 
In one embodiment, the end of connector 36 is positioned by holder 34 as 
shown in FIG. 6. At the end of connector 36 is a ceramic insulating cap 
40. In order for piezoelectric igniter 26 to operate, a complete 
electrical circuit must be formed. This is accomplished by placing wire 36 
in the path of the flowing volatile fluid and causing a spark to jump from 
wire 36 to the interior wall 25 of mixing chamber 24. 
Another embodiment is shown in FIG. 8 where the holder 34 has been 
eliminated. Herein the inherent stiffness of wire 36 places wire 36 at the 
proper location with torch tip assembly 15. 
Igniter 26 is manually activated by button 28. When button 28 is pushed, 
the flow of electrical potential through connector 36 causes a spark to 
jump from wire 36 to inside wall 25. Location of the spark is controlled 
by a pin-hole made in the insulation surrounding wire 36. The mixture of 
the combustible gas and air or oxygen then ignites into a flame. If 
desired a lever assembly 42 as shown in FIG. 5 may be used to push button 
28. 
The continuing flow of pressurized fluid and air or oxygen causes the flame 
to stabilize at flame holder 30 which is mounted in the third portion of 
the tubular housing. Flame holder 30 both stabilizes the base of the flame 
and fixes the flame in position with respect to torch tip assembly 15. As 
shown in FIG. 1, extending from flame holder 30 is flame tube 32 which 
shapes the flame. Wire 36 is entirely contained within mixing chamber 24. 
This mounting protects the electrical connections over portable torches 
where the connections are mounted externally of the mixing chamber. An 
alternate method of mounting the piezoelectric igniter 26 is shown in FIG. 
8. Herein housing 27 is mounted closer to source 12. Connector 36 passes 
outside of nozzle jet pump 20 along interior wall 25. The design of torch 
tip assembly 15, less the piezoelectric igniter is similar in some 
respects to that marketed by the Turner Torch Division of CooperTools, a 
marketing arm of Cooper Industries under part number PR3600 or LP5555. 
FIGS. 3 and 4 illustrate the seals formed at the various threaded 
connections 50 and 52 within torch tip assembly 15. In FIG. 3 it may be 
seen that orifice holder 19 is surrounded by two o-rings 44 which seal 
against the inside of connecting tube 16. Washer 46 provides additional 
sealing for threaded connection 50. Similarly washer 48 provides a sealing 
effect for threaded connection 52. FIG. 7 illustrates an alternate method 
of connecting torch tip assembly 15 to source 12. Therein a lock nut 54 is 
threadably connected to male fitting 60 on top of source 12. A seal is 
provided by the action of washer 56 against flange 58. 
OPERATION 
When it is desired to ignite the portable self-igniting torch assembly 10 
the pressurized combustible fluid is caused to flow from container 12 by 
opening valve 14. In the device shown in the figures, the container is a 
small propane gas tank. In a welding torch the container may be a large 
source of combustible fluid. When the combustible fluid flows from its 
container it enters torch tip 15. After entering torch tip 15, air or 
oxygen must be added to the flowing combustible gas to produce a usable 
flame. This is accomplished by drawing in air or oxygen through holes 22. 
When the oxygen and combustible gas are mixed together, a highly volatile 
mixture is formed. This highly volatile mixture is ignited by a spark 
which is introduced into the flow path of the volatile mixture. The spark 
is caused by an electrical potential completing a circuit between wire 36 
and wall 25. The placement of the spark is governed by making a small hole 
in the insulation around wire 36. Cap 40 prevent the spark from emanating 
from the end of wire 36. 
It has been found that if wire 36 passes within torch tip assembly 15 it is 
protected. This provides an advantage to the user a rough handling of the 
torch assembly 10 will not break the electrical connection between housing 
27 and wire 36. 
Additionally, it has been found that mounting piezoelectric igniter 
assembly 26 higher up on torch tip 15 in heat resistant housing 62 so that 
it is downstream of orifice 18 places manually activated button 28 in a 
much more convenient location for the torch user. It has been found that 
such placement lowers the manufacturing costs. In addition, this placement 
provide for easy changing of tips (from large to small, for example) by 
providing a self contained electrical ignition system in a permanently 
attached position to each tip. 
There is thereby provided by the portable torch assembly 10 of the present 
invention a torch with internal connections for the piezoelectric igniter 
and a conveniently mounted manual activator button for a piezoelectric 
igniter. 
While the self-igniting portable torch assembly 10 of the present invention 
has been described with reference to the preferred embodiments, it is 
understood that the additional embodiments of this invention will become 
apparent to those of ordinary skill in the art once having read the 
foregoing specification. Such additional embodiments are within the scope 
of the appended claims.