US3436164A

US3436164A - Piezoelectrically ignited gas torch

Info

Publication number: US3436164A
Application number: US623293A
Authority: US
Inventors: Theodore F Deucher
Original assignee: Clevite Corp
Current assignee: Clevite Corp
Priority date: 1967-03-15
Filing date: 1967-03-15
Publication date: 1969-04-01
Anticipated expiration: 1986-04-01
Also published as: DE1613805B2; DE1753885A1; DE1753885C3; GB1207180A; DE1753885B2; DE1613805A1; GB1207179A; FR1557883A

Description

April 1, 1969 "r. F. DEUCHER PIEZOELECTRICALLY IGNITED GAS TORCH Filed March 15, 1967 28 INVENTOR.

THEODORE F.DEUCHER MW ATTORNEY United States Patent 3,436,164 PIEZOELECTRICALLY IGNITED GAS TORCH Theodore F. Deucher, Par-ma, Ohio, assignor to Clevite Corporation, a corporation of Ohio Filed Mar. 15, 1967, Ser. No. 623,293 Int. Cl. F23q 7/12 US. Cl. 431-255 21 Claims ABSTRACT OF THE DISCLOSURE This invention relates generally to a gas torch and, more particularly, to a torch of the type having a piezoelectric spark generator for igniting the gas at the nozzle outlet.

In the prior art piezoelectrically ignited gas torches of various types are already known, for instance, see copending application Ser. No. 183,830, filed Mar. 30, 1962, assigned to the same assignee as the instant invention and Patent No. 3,255,803. Similarly known are gas torches equipped with battery powered spark igniters, see Patent 3,155,140.

One of the problems with self-igniting torches generally stems from the difficulty of devising an electrically operable structure, particularly a nozzle portion, which will not interfere with or otherwise affect the gas flow. The insulator must be protected from the heat of the flame, and because of the small amount of energy available, usually only enough for one tiny spark, electrical losses due to leakage must be kept to an absolute minimum.

Applicant has recognized that these and other related shortcomings may be overcome by providing a bare, needle type, electrode supported concentrically within the nozzle by an insulator located remote from the tip with cooling being provided by physical contact of the electrode with the combustible gas. Furthermore, the torch, and more particularly the ignition system thereof, is constructed and arranged in such manner that the voltage increase phase, i.e. the period until a sufiiciently high voltage level for sparking is achieved, takes place in a segment of the torch unaflected by electrical leakage at the tip. This is achieved by providing a voltage breakdown control gap in the ignition circuit which prevents ionization in the gap until the proper voltage level is reached, i.e. by providing a resistance across the voltagecontrol gap which is substantially greater than the effective resistance across the spark gap. Consequently, dissipation of electrical energy proximate to the bare electrode and a potential misfiring as a result of such leakage is thereby eliminated. In addition, the ignition device provides enough energy for several sequential sparks at each operation.

It is therefore the primary object of this invention to provide a piezoelectrically ignited gas torch which obviates the difficulties experienced by prior art devices.

It is another object of this invention to provide a piezoelectrically ignited gas torch in which a needle electrode is utilized which offers protection against premature ignition, and which is effective to provide a plurality of sequential sparks with a single actuation of the igniter to assure ignition.

Another object of this invention is to provide a torch of the type above described in which a voltage control Patented Apr. 1, 1969 spark gap is utilized to block the voltage flow until a sufficiently high level is reached to ionize and break down to gap so as to cause the electrical energy to spark strongly across the igniting spark gap located in the nozzle.

It is another object of this invention to provide a gas torch of the type hereinabove described in which the nozzle and gas conduit portion as Well as the electrode housed therein or aflixed thereto are quickly disconnectable from the handle or main body of the torch.

It is another object of this invention to provide a gas torch of the type as above described in which the lever for manually actuating the piezoelectric igniter is also effective to operate the main gas supply valve.

For a better understanding of the present invention, together with other and further objects thereof, reference is had to the following description taken in connection with the accompanying drawings, and its scope will be pointed out in the appended claims.

An aspect of the present invention resides in the provision of a piezoelectrically ignited gas torch which includes a handle which forms a housing and a valve arrangement secured to the handle and connectible to a source of gas under pressure. A nozzle with a customary outlet is provided and a conduit extends from the nozzle and is mounted within the handle. The nozzle and the conduit are formed at least in part of electrically conductive material. A small tube extends between the conduit and the valve for providing a fluid passageway there between. Disposed Within the handle is a piezoelectric igniter which is effective, upon actuation thereof, to provide a high voltage spark source. An electrical circuit is operatively connected to the igniter and extends between the latter and the nozzle. A solid, axially straight, cylindrical metal electrode, such as a needle type electrode, is electrically coupled to the circuit and is substantially concentrically arranged within the nozzle. In the preferred embodiment, the tip of the electrode forms a point and terminates proximate to the nozzle outlet to form a spark gap.

An aspect of the present invention resides in the provision of a piezoelectric ignition device which includes a manually actuated piezoelectric voltage generating system effective, upon actuation thereof, to provide a high voltage spark source. An electric circuit is associated with the piezoelectric generating system for transmitting the generated voltage. The circuit includes a spark air gap and a voltage control gap arranged in series with the control gap and elfective to block the voltage across the gap until the voltage within the circuit has reached a predetermined level, whereby the voltage then ionizes the control gap and without any substantial dissipation of energy sparks across the spark air gap.

In the drawing:

FIGURE 1 is a perspective view of the gas torch hereinunder consideration;

FIGURE 2 is a side view portion of the torch shown tion; and

FIGURE 3 is a side view of the handle with one half thereof removed to show the individual components (some of them in cross section) secured therein.

Referring now to the drawing there is shown in FIG- URES 1 to 3 a torch 10 which includes a hollow handle 12 molded of plastic material, in two halves, one of which is shown in FIGURE 3. The two halves are held together by transversely protruding bolts (not shown) and a metal sleeve 11 with a radially inwardly turned flange (not visible) slipped over the two handle halves. The internal configuration of the handle 12 is such that it may suitably receive at one end thereof a valving arrangement 14 having at the rear end a threaded gas inlet 16 connectible to a source of gas under pressure and a of the nozzle and conduit partly in longitudinal secgas outlet 18 connected to the inlet by

passageways

20, 21 which are effective to permit the gas to flow therebetween. A tubular extension 24, extending integrally and perpendicular to the longitudinal axis of the valve body 14 and intermediate the

ends

16 and 18, is provided with a fluid passageway 22 which terminates into a junction of

passageways

20, 21 above mentioned. The tubular extension 24 receives within an enlarged segment of the passageway 22 a flame control valve 26 which includes a stationary hollow cylindrical member 30 threadedly secured within the passageway and adapted to receive a piston 32 having at one end a circular handle 28 for manual manipulation of the valve. The piston is sealingly disposed within member 30, see O-ring 33, and extends transversely into the

passageways

20, 21 to control the flow of gas between the inlet and

outlet

16 and 18, respectively, by effectively blocking the junction of the passageways.

The forward passageway 21 is adapted to receive therein a plunger responsive shut-off valve 34 of the type used in automotive tires. The valve 34 completely blocks the fluid flow through the passageway 21 and the fluid is forced to flow through the channels of the valve 34 in response to actuation thereof by means of a push rod 84 which causes a plunger 35 of the valve 34 to be moved axially inward to open the valve while the plunger is maintained in that position. The gas which is permitted to flow through valve 34 empties into fluid chamber 36 and fiows thereafter through tubing 38 toward the forward section of the torch.

The tube 38 terminates into a bayonet type quick disconnect and coupler assembly having a spring biased female member 40, see FIGURE 3, and a complementary male member 42, the latter forming a part of gas conduit 46 as shown in FIGURE 2, which is inserted into the female member for a fluid tight connection. The

members

40 and 42 are securely held together by a pin 43 and groove 45 arrangement, the pin 43 extending radially from the interior surface of the female member. The groove 45 is substantially L-shaped and formed in an enlarged diameter segment 47 of the male member. The male member is provided with a radial opening 44 to permit air to enter into the conduit 46 for mixing, in suitable proportion, with the gas such as acetylene. The gas carrying conduit 46 is integrally connected with the male member 42 of the quick disconnect device and terminates at the opposite end into a nozzle portion 48. The nozzle 48 is or a tubelike construction and the axes of elongation of the nozle and the conduit 46 intersect and define an included angle of not less than 90. The nozzle 48 has a tubular extension 50 located remote from the nozzle outlet 54 and this tubular portion 50 is axially spaced from the intersection of the axis. The gas thus flows through the conduit 46 and into the nozzle 48 and exists through the tapered portion 52 and ultimately through the nozzle outlet 54. In order to accommodate the electrical system, which is hereafter described, the nozzle 48 and the conduit 46 including the quick disconnect and

coupler members

40, 42, are formed of, at least in part, electrically conductive material.

Turning now to the electrical characteristics of this invention, there is shown in FIGURE 3 a piezoelectric generator assembly 56 of the type shown and described in copending application Ser. No. 574,103, assigned to the same assignee as the present invention. The assembly 56 comprises a plurality of piezoelectric elements 58 having a center electrode 66 and being disposed within a rigid frame 60. The frame is movably anchored within the interior of the handle 12. A rolling cam arrangement (not shown) in conjunction with a manually actuated lever 62 is adapted to squeeze the piezoelectric element 58 along its longitudinal axis and against the frame 60 so as to generate an electric potential. Details of a piezoelectric igniter generally are well known in the art and further reference may be had to US. Patents 4 3,093,333, 3,101,420 and 3,114,059. The push rod 84 is pivotally mounted to the lever 62 and is caused to move axially rearward in response to actuation of the lever. Electrically connecting to and extending from center electrode 66 is a lead wire 64 which terminates at the opposite end by means of a metal pin 68 slightly beyond the exterior surface of the handle 12 and more specifically at the end face 13 thereof. The lead wire 64 is suitably insulated and the uninsulated portion 68 of the lead wire 64 is encased in a ceramic insulator sleeve 70 rigidly mounted in the handle 12.

Referring now again to FIGURE 3, the electric circuit includes, aside from the components already mentioned, a lead wire 72 and a terminal assembly composed of a housing 74 for securely receiving a ceramic insulator sleeve 76 which houses the terminal portion of lead wire 72 and, in the same manner as aforedescribed With respect to the terminal end of lead wire 64, there is arranged a metal pin type electrode 78 which extends from the lead wire 72 to the exterior surface of the ceramic sleeve 76 and, in assembled condition of the torch, the front faces of the

electrodes

68 and 78 are mechanically as well as electrically juxtaposed and the space therebetween thus does not vary to provide a voltage breakdown control gap which is effective to prevent ionization between the gap end until the proper voltage level is reached in the system and more specifically in that portion of the system constituted by

members

66, 64 and 68. The lead wire or electrical conductor 72 is insulated from and extends externally alongside the conduit portion 46 in suitable metal tubing 73 and terminates into the tubular extension 50 of the nozzle 48.

Within the tubular extension 50 there is disposed a ceramic sleeve 80 for rigidly securing and insulating from the metal nozzle a solid axially straight, cylindrical metal electrode 82, preferably a bare needle type electrode, which extends concentrically through the nozzle and terminates substantially flush with the nozzle outlet 54. The space between sleeve 80 and end cap 81 of tubular extension 50 is filled with suitable insulating material. The needle electrode is tapered toward the outlet 54 and the terminal end constitutes a point electrode which forms together with the outlet 54 a physically constant spark air gap. It will be noted that the portion of the electrical circuit between the two gaps is closed at all times and that the two gaps are electrically in series. It has been found that an electrode with a relatively large end surface inhibits sparking across the gap and a much lower voltage is required to ionize or break down the air gap in the case of a needle point electrode. The end remote from the tapered portion of the electrode 82 is suitably electrically connected to the lead wire 72.

In operation the flame control valve is adjusted so as to provide suflicient gas for the desired flame level and upon squeezing the lever 62 towards the handle 12, the push rod 84 protruding into the fluid chamber 36 axially moves plunger 35 of the shutoff valve 34, thereby opening the valve 34 establishing gas to flow into and through the tubing 38 until the same reaches the outlet 54 of the nozzle 48. Simultaneously with causing the valve 34 to open, the radial movement of the lever 62 causes the piezoelectric element 58 to be squeezed against frame 60 and to generate a voltage on electrode 66. The voltage gradually builds up to the desired level within the circuit constituting the electric assembly located Within the handle until the voltage is able to break down the gap existing between

electrodes

68 and 78 and ionize the space therebetween. Once the voltage reaches this predetermined level it is quickly permitted to flow through the lead wire 72 and needle electrode 82 and is thereafter effective to ionize the gap between the pointed end 83 of needle electrode 82 and the adjacent nozzle end (see 54) to ignite the gas at that location. Fully depressing the lever 62 on or against the handle 12 is sufficient to provide a plurality of sequential sparks at gap 54. The gas supply is shut off by releasing the lever 62 and permitting the rod 84 to move axially forward thereby releasing the plunger 35 from the open position of the valve 34.

As the nozzle portion of the torch is mechanically connected to the handle portion by means of a quick disconnect device of the bayonet type and the electric circuitry located adjacent to gas carrying conduit 46 and within nozzle 48 does not require a mechanical contact with the circuitry located within the handle, it will be readily appreciated that the construction lends itself for a quick changeover between nozzles of difierent types. Moreover, the bayonet type coupler provides a fixed predetermined orientation between the handle and the nozzle.

For most purposes it will be suflicient to manually hold the lever 62 in operating position. However, a retaining latch, not shown, may be provided to obviate the need for keeping the lever in a depressed condition.

While there have been described what are at present considered to be the preferred embodiments of this invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention, and it is aimed, therefore, in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What is claimed is:

1. In a piezoelectrically ignited gas torch, having a handle;

valve means secured to said handle and connectible to a source of gas under pressure;

a tube-like nozzle having an outlet for forming a spark gap and a gas conduit extending from said nozzle and secured to said handle, said nozzle and conduit being formed at least partly of electrically conductive material;

a tube between and connecting to said conduit and said valve for providing a fluid passageway therebetween;

a piezoelectric igniter effective, upon actuation thereof,

to provide a high voltage spark source;

electric conductor means connected to said ignited and extending between the latter and said nozzle; wherein the improvement comprises:

a solid, axially straight, cylindrical metal electrode substantially concentrically disposed within said nozzle and supported therein by insulator means located remote from the spark gap; and wherein said electrical conductor means includes a voltage breakdown control spark gap.

2. In a piezoelectrically ignited gas torch according to claim 1,

wherein said electrode is of the needle type and the outer surface thereof is predominantly uninsulated,

and wherein said electrode is tapered in the direction of the nozzle outlet,

and the needle tip of said electrode terminates proximate to said outlet to form a spark gap.

3. In a piezoelectrically ignited gas torch according to claim 1,

wherein said nozzle and said conduit are elongated and their axes of elongation intersect and define an included angle of not less than 90 degrees,

said nozzle having an axial, tubular, extension, remote from said outlet, axially spaced from the intersection of said axes;

said electrodes, more particularly the end remote from the nozzle outlet, extending into said tubular extension;

and electrical insulation between said electrode and said extension.

4. In a piezoelectrically ignited gas torch according to claim 3, wherein said electrical conductor means is coupled to said electrode within said nozzle extension.

5. In a piezoelectrically ignited gas torch according to claim 4, wherein said electrical conductor means includes a portion insulated from and extending externally alongside said conduit.

6. In a piezoelectrically ignited gas torch according to claim 1, and a bayonet type quick disconnect and coupler means secured to said handle and connectible to said conduit;

and wherein said tube for providing said fluid passageway terminates into said coupler means.

7. In a piezoelectrically ignited gas torch according to claim 1, wherein said electrical conductor means is composed of two portions, the first portion thereof extending from said igniter to an outer surface of said handle, and one end of the other portion is physically and electrically juxtaposed, in spaced relation, to the end of said first portion.

-8. In a piezoelectrically ignited gas torch according to claim 1, wherein said valve means includes a fluid inlet and outlet, and a plunger responsive shut ofi? valve positioned within the passageway of said outlet.

9. In a piezoelectrically ignited gas torch according to claim 8, and a flame control valve interposed between the inlet and outlet of said valve means and effective for regulating the flow of fluid therebetween.

10. In a piezoelectrically ignited gas tor-ch according to claim 8, wherein said igniter includes a frame, piezoelectric means suitably disposed within said frame, and means for manually actuating said piezoelectric means;

a pusher rod disposed in operative relation to said shutoff valve and connected to said actuating means; the actuating means being effective to simultaneously apply a force upon said piezoelectric means to generate a voltage and to move said pusher rod for operating said shut-01f valve.

'11. In a piezoelectric device for igniting a combustible gas:

piezoelectric voltage generating means effective, upon actuation thereof, to provide a high voltage spark source;

a nozzle having a gas outlet, and a gas conduit extending from the other end of said nozzle and connectible to a source of gas;

a solid, elongated, needle type, metal electrode substantially concentrically disposed within said nozzle with the tapered end being located in the direction .ofthe opening of the nozzle to form an ignition gap therebetween;

electrical conductor means connected to and between said piezoelectric voltage generating means, said noz zle, and said needle electrode to establish an electric circuit and including a voltage breakdown control gap effective to prevent ionization of the ignition gap until said generating means has reached a predetermined voltage level.

12. In a piezoelectric ignition device:

manually actuated piezoelectric voltage generating means effective, upon actuation thereof, to provide a high voltage spark source;

an electric circuit electrically associated with said generating means for transmitting the generated voltage, said circuit including a spark air gap and a voltage control gap, the two gaps being electrically in series, said control gap being effective to block the voltage across its gap until the voltage within the circuit has reached a predetermined level, whereby the voltage then ionizes the voltage control gap and without any substantial dissipation of energy spanks across said spark gap.

'13. In a piezoelectric ignition device according to claim 12, wherein electrodes comprising part of said circuit are electricaly and physically juxtaposed, the terminal end of each of said electrodes facing each other having a spherical configuration spaced apart to form said voltage control gap.

14. In a piezoelectrically ignited gas torch, comprising: handle means connectible to a source of gas; manually actuated piezoelectric voltage generating means within said handle means, effective, upon actuation thereof to provide a high voltage spark source; a nozzle extending from the handle means and providing a spark gap and a conduit for the gas; and an electric circuit between said piezoelectric voltage generating means and said spark gap and including a voltage level control gap electrically in series with said spark gap, said control gap being effective to block the voltage across its gap until the voltage Within said circuit has reached a predetermined level and ionizes the voltage control gap and without any substantial dissipation of energy sparks across said spark gap.

15. In a piezoelectric ignition device according to claim 14, wherein said voltage control gap is located between said nozzle and said handle.

16. In a piezoelectrically ignited gas torch according to claim 14, wherein each of the two gaps are constantly spaced.

17. In a piezoelectrically ignited gas torch according to claim 14, wherein the resistance across the voltage control gap is substantially greater than the effective resistance across the spark gap.

18. In a piezoelectrically ignited gas torch according to claim 14, wherein that portion of the electric circuit located between the two gaps is closed at all times.

19. In a piezoelectric ignition device according to claim 12, wherein each of the two gaps are constantly spaced.

20. In a piezoelectric ignition device according to claim 12, wherein the resistance across the voltage control gap is substantially greater than the effective resistance across the spark gap.

21. In a piezoelectric ignition device according to claim 12, wherein that portion of the electric circuit located between the two gaps is closed at all times.

References Cited UNITED STATES PATENTS 2,402.,7 63 6/ 1946 Longini. 2,672,924 3/ 1954 Anthes. 2,880,792 4/ 1959 Raskin. 3,070,153 12/ 1962 Flynn. 3,255,803 6/1966 Hach et al.

FREDERICK L. MATTESO-N, JR., Primary Examiner.

E. G. FAVO-RS, Assistant Examiner.

U.S. DEPARTMENT OF COMMERCE PATENT OFFICE Washington, D.C. 20231 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent NO. 3,436,164 April 1, 1969 Theodore F. Deucher It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 47, "a" has been omitted. Column 2, line 3, "to", first occurrence, should read the Column 3, line 48 "or" should read of line 55 "exists" ShULl11 read exits Column 4 line 44 "the", first occurrenc should read that Column 5, line 40, "ignited" should read igniter Signed and sealed this 21st day of October 1969.

(SEAL) Attest:

WILLIAM E. SCHUYLER, JR.

Edward M. Fletcher, J r.

Commissioner of Patents Attesting Officer