AU670208B2

AU670208B2 - Igniter for a fluid burning appliance

Info

Publication number: AU670208B2
Application number: AU73087/94A
Authority: AU
Inventors: Philip Timbrell; Alexander Ulk
Original assignee: Utilux Pty Ltd
Current assignee: Utilux Pty Ltd
Priority date: 1993-09-22
Filing date: 1994-09-20
Publication date: 1996-07-04
Anticipated expiration: 2014-09-20
Also published as: AU7308794A

Description

1- P/00/0O11 Regulation 3.2

AUSTRALIA

Patents Act 1 990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Invention Title: Igniter For A Fluid Burning Appliance

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The following statement is a full description of this invention, including the best method of performing it known to us: S S. S

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S S S S. GH&CO REF: P14589-GN:TJS:JM UTILUX REF: Gas Igniter Assembly 411 14589-GN -2- The present invention relates generally to an igniter suitable for use with a fluid burning appliance, and particularly, but not exclusively, to an igniter suitable for use with a domestic gas burning appliance, such as a domestic gas cooker, for example.

Gas cooker igniters are known which comprise a stainless steel electrode mounted in an insulating ceramic housing, the electrode being connected to a conductive lead leading to an operating switch on the cooker control panel. On application of a high voltage to the electrode on actuation of the control, a spark is produced between the electrode and the gas cooker hub to ignite gas flowing from the hub. Sensor circuitry is usually provided in the arrangement for detecting a low resistance path between the electrode and the hub (ionised particles due to a flame being ignited at the gas cooker provide a low resistance path). If no low resistance path is detected, further sparks will be produced until ignition occurs.

S 20 It has been found that this type of prior art igniter tends to fail after relatively few uses. The applicants have carried out research to determine reasons for the early failure. They believe that failure may be due to the creation of a low resistance path within the igniter itself and away from the electrode, due to build- S* up of contaminating moisture within the electrode assembly in the harsh environment of the gas cooker flame and imperfect insulation of the electrode conductive lead arrangement. In the prior art arrangement the electrode 30 is usually connected to the conductive lead by a receptacle pin extending from the electrode and a further connector crimped on to the pin. A substantial amount of exposed conductive material therefore extends within the insulating ceramic housing. If gaps exist or are created due to environmental wear and contamination in the housing this can lead to a low resistance path as an alternative for conduction to the electrode/hub path, leading to breakdown of the igniter and failure to 411/s:14589GN 3 produce sparks.

The present invention provides an igniter for a fluid burning appliance, comprising an insulating housing having a passageway extending therethrough, an electrode mounted at one end of the passageway and a conductive lead extending through the passageway to the electrode and being electrically connected thereto, the electrode having a body portion which extends into the passageway in the housing, the body portion of the electrode having a further passageway extending therein, the further passageway receiving an end of the conductive lead to make electrical connection therewith.

In at least preferred embodiments, the further passageway in the electrode enables an excellent electrical connection between the conductive lead and the electrode. The electrode is preferably crimped on to the conductive lead to make the electrical connection. The electrode is preferably an integral unitary body. There is no need for any intermediate electrical connection 20 between the lead and the electrode as in the prior art.

The lead can be connected directly to the electrode.

Preferably, the remaining exposed conductor lead in the housing passageway is covered in insulation, all the way up to the electrode. This provides additional insulation to assist in preventing early failure of the arrangement.

To provide further protection against failure, the electrode and conductive lead are sealed within the insulating housing by means of a high temperature I.e. 30 resistant adhesive or cement. The high temperature adhesive or cement preferably extends over the conductive portion of the electrode extending within the housing passageway and over the insulation covering the conductive lead.

The electrode preferably comprises a head portion which extends out of the passageway and is provided with a flat top to provide a surface for the spark.

Preferably, a portion of the body portion extending to 411/s:14589GN I I 4the flat head portion is tapered. During manufacture, the electrode is preferably drawn within the housing passageway body portion first. The passageway and taper are dimensioned such that as the taper is drawn within the body portion a close fit between the electrode and the passageway is created. In at least preferred embodiments this provides extra security against impurity leakage to the passageway and assists in extending the life of the igniter.

The present invention further provides an electrode for a fluid burning appliance igniter, the electrode having a body portion arranged to extend into a passageway in an igniter housing, and a head portion arranged to extend out of the passageway, the body portion having a further passageway extending therein for receiving an end of a conductive lead for electrical connection thereto.

The electrode of this aspect of the invention may have all the features of the electrode discussed in 20 relation to the first aspect of the invention above.

The present invention yet further provides a method of manufacturing an igniter tcr a fluid burning appliance, comprising the steps of providing an insulating housing having a passageway extending therethrough and an electrode having a body portion with a further passageway extending into the body portion, inserting a conductive lead into the further passageway and crimping the body portion of the electrode on to the sC conductive lead, inserting the body portion of the S 30 electrode with the conductive lead into one end of the housing passageway and sealing the assembly within the passageway housing by a high temperature resistant adhesive or cement extending over at least part of the length of the housing passageway and by a rapid setting adhesive or cement at a portion of the housing passageway remote from the electrode.

Features and advantages of the present invention will become apparent from the following description of 411/s:14589GN i i embodiments thereof, by way of example only, with reference to the accompanying drawings, in which; Figure 1 is a side view of an igniter in accordance with an embodiment of the present invention; Figure 2 is a cross-sectional view through the igniter along line AA of figure 1, and Figure 3 is a perspective view of the electrode of the igniter of figures 1 and 2.

The embodiment shown in the figures comprises an insulating ceramic housing 1 having a cylindrical passageway 2 which extends axially through the housing 1 from one end to the other. An electrode 3 is mounted within the passageway 2 at one end thereof. The electrode is shown in more detail in figure 3. A body portion 4 of the electrode 3 extends into the end of the passageway 2. A further passageway 5 is provided within the body portion 4 of the electrode 3. The passageway extends within the body portion 4 towards a head portion 6 of the electrode 3.

0: 20 The passageway 5 receives therein one end of a conductive lead 7 (figure The body portion 4 is crimped to the lead 7 in order to make a good electrical connection within the passageway 5. The crimp is indicated in Figures 1 and 2 by the depression on the electrode designated by reference numeral 13.

The conductive lead 7 extends from the electrode end e of the passageway 2 through the passageway 2 and out of the end 8 opposite the electrode end. The portion of the 0000 "0 conductive lead 7 not sitting within the passageway 5 and S 30 the electrode 3 and extending through the passageway 2 is covered with insulating material 9. The insulating material 9 is preferably resistant to high temperatures.

It will be seen from the drawings that the conductive lead 7 is insulated for most of its path of travel within the passageway 2 by the insulating material 9. It is insulated virtually all the way up to the electrode 3 and then passes into the passageway To provide further protection, the electrode and 411/s:14589GN I I 6 conductive lead are sealed within the housing 1 by means of a high temperature resistant adhesive or cement which fills the gap 10 between the electrode 3/lead 7 and housing 1 walls. The adhesive or cement extends over the conductive portion 4 of the electrode 3 extending within the passageway 2 as well as over at least a part of the insulating material extending within the passageway 2.

Note that the position of the fast curing adhesive or cement in the passageway is variable. It need not be absolutely at the end, for example, but could be part way in the passageway.

A tapered portion 12 of the electrode 3 extends from the body portion 4 to the flat head portion 6. During assembly, this tapered portion 12 is drawn within the electrode end of the passageway 2 (it will actually be further within the passageway 2 than shown in the figures). This provides a tight seal between the housing 1 and the electrode 3.

In operation, the igniter will be mounted adjacent a 20 hub on a domestic gas coo-er. Because of the novel construction of the igniter, in at least preferred embodiments it will be difficult to find a path to earth from the head 6 passing down the igniter. Failure rate will therefore advantageously be improved.

Assembly of the igniter of the embodiments shown in the drawings preferably takes place by the following II process.

Firstly, the electrode 3 is crimped to the end of the conductive lead 7, the conductive lead 7 being 30 insulated over the majority of the length of the conductive lead 7. The assembly is then slid within the housing and a high temperature adhesive or cement within area 10. The electrode is drawn within the passageway 2 so that the taper 12 provides a good fit at the top end of the passageway 2.

The method of application of the adhesives or cements is as follows. Before the assembly is slid within the housing 1, the high temperature adhesive or 411/i:14589Gl 7 cement is applied to the electrode body 4 and at least part of the insulation 9. The assembly is then slid within the housing 1 such that the high temperature adhesive or cement fills the area 10, completely covering the electrode body 4 and extending at least part way down the insulation 9 within the passageway 2.

A suitable high temperature cement would be Morganite high temperature ceramic cement.

It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

*o *e *e*ee *ee 411/s:14589GN

Claims

1. An igniter for a fluid burning appliance, comprising an insulating housing having a passageway extending therethrough, an electrode mounted at one end of the passageway and a conductive lead extending through the passageway to the electrode and being electrically connected thereto, the electrode having a body portion which extends into the passageway in the housing, the body portion of the electrode having a further passageway extending therein, the further passageway receiving an end of the conductive lead to make electrical connection therewith.

2. An igniter in accordance with claim 1, the further passageway of the body portion being crimped to the conductive lead to make electrical contact.

3. An igniter in accordance with claim 1 or 2, the electrode being a integral unitary body.

4. An igniter in accordance with any one of claims i1, 2 or 3, the electrode having a tapered portion extending 20 from the body portion to a head portion, the tapered portion seating within the one end of the passageway to provide a tight fit thereto.

An igniter in accordance witL any one of the preceding claims, the conductive lead being protected by insulating material which extends through the passageway '0:6 in the housing substantially to the body portion of the electrode

6. An igniter in accordance with claim 5, the arrangement being such that the body portion of the S 30 electrode extends into the passageway only a short way relative to the length of the passageway, such that the insulated portion of the conductive lead extends through the most part of the passageway.

7. An igniter in accordance with any one of the preceding claims, the conductive lead and body portion of the electrode being sealed within the housing passageway by a high temperature resistant bonding material, the bonding material extending over at least part of the 411/s:14589GN I I I 9 length of the passageway.

8. An electrode for a fluid burning appliance igniter, the electrode having a body portion arranged to extend into a passageway in an igniter housing, and a head portion arranged to extend out of the passageway, the body portion having a further passageway extending therein for receiving an end of a conductive lead for electrical connection thereto.

9. An electrode in accordance with claim 8, being an integral unitary body.

An electrode in accordance with claim 8 or 9, the electrode having a tapered portion extending from the body portion to the head portion, the tapered portion being arranged to seat within one end of the housing passageway to provide a tight fit thereto.

11. A method of manufacturing an igniter for a fluid burning appliance, comprising the steps of providing an insulating housing having a passageway extending E" 'therethrough and an electrode having a body portion with 20 a further passageway extending into the body portion, inserting a conductive lead into the further passageway and crimping the body portion of the electrode on to the conductive lead, inserting the body portion of the electrode with the conductive lead into one end of the housing passageway and sealing the assembly within the passageway housing by a high temperature resistant bonding material extending for most of the length of the housing passageway. 0*09 "DATED this 16th day of September 1994 UTILUX PTY LIMITED By their Patent Attorneys GRIFFITH HACK CO 411/8:14589GN ABSTRACT IGNITER FOR A FLUID BURNING APPLIANCE The present invention relates to igniters for fluid burning appliances, particularly igniters for domestic gas cookers. A problem with presently known igniters is failure after only a short number of actuations, due to the development of low resistance paths within the igniter housing. The present invention provides an igniter comprising an electrode mounted within an insulating housing, the electrode having a body portion which extends into a passageway in the insulated housing, the body portion having a passageway therein which receives a conductive lead to make electrical connection with a power source. The electrode lead is insulated all the way up to the electrode as well as beig seated within the insulating housing. The structure results in improved insulation assisting in preventing early failure 20 of the arrangement. S e 9 SS f f ft t f f 411/s:14589GN