GB2299661A - An igniter for a fluid burning appliance - Google Patents

Abstract

An igniter for a fluid burning appliance, in particular to ignite fluid in a domestic gas oven or griller comprises an insulating ceramic housing 12 having a passageway therethrough, a conductive slug 18 seated entirely within the passageway, the slug having a first end with a first passageway therein receiving an end of an electrode 14 in crimp conductive contact therewith, the other end of the metal slug having another passageway in it and receiving an exposed end of a conductive lead 25 in crimped connection. The conductive lead transmits power for arcing from a power source. The entire connection arrangement is therefore seated within the passageway in the insulating housing.

Description

AN IGNITER FOR A FLUID BURNING APPLIANCE The present invention relates generally to an igniter suitable for use with a fluid burning appliance, and, more particularly, but not exclusively, to an igniter suitable for use in the oven and/or griller of a domestic gas cooker.

Known igniters for domestic ovens and grillers comprise an insulating ceramic housing, an electrode comprising an elongate piece of stainless steel which passes completely through a passageway within the ceramic housing so that portions of the electrode extend from each end of the passageway. One portion of the electrode is bent to provide a portion extending away from the major portion of the electrode. This extending portion has a narrow tip to provide an active end of the electrode for producing a discharge to earth (main body of cooker or griller) on application of a voltage to the electrode. The other end of the electrode is connected to a conductive lead, via a crimp connection. The other end of the electrode may be machined to provide a suitable surface for crimp connection. Voltage to cause the discharge is applied via the conductive lead.

This arrangement suffers from a number of problems. Firstly, the stainless steel electrode extends completely through the housing, with the non-active end extending from one side of the housing to be connected with the conductive lead. A significant conductive portion of the electrode/crimp connection is therefore exposed, out of the insulating housing. This can lead to a risk of arcing to earth on that side of the electrode, decreasing the affectivity of the igniter and it's lifetime. Secondly, the igniter is applied in an extremely high temperature environment. The exposed crimp connection between the conductive lead and the end of the electrode is exposed to significant thermal cycling. This can lead to relaxation of the crimp connection. Thirdly, the electrode is generally required to be made of high quality material, usually expensive stainless steel.As the electrode is quite sizeable, because it has to extend entirely through the insulating housing, the cost of the electrode is relatively high.

The present applicant have devised an arrangement for an igniter which, in at least a preferred embodiment, addresses the above problems.

The present invention provides an igniter for a fluid burning appliance, comprising an insulating housing having a passageway extending therethrough, an electrode extending from one end of the passageway, an insulated conductive lead extending into the other end of the passageway, and a conductive connecting member electrically connecting the electrode and conductive lead within the passageway.

The conductive connecting member preferably comprises a conductive body seated within the insulated housing passageway, the conductive body having a first end with a passageway extending therein and a second, opposite end, with a passageway extending therein, the first end receiving an end of the electrode and being crimped thereto and the second end receiving an end of the conductive lead and being crimped thereto.

The conductive member therefore provides an electrical and mechanical connection between the conductive lead and the electrode, this connection being made entirely within the passageway of the insulating housing.

At the conductive lead end, therefore, in at least preferred embodiments, no conductive material is exposed and arcing to ground on that side therefore ceases to be a problem. Further, because the electrode (which is usually expensive stainless steel) only need extend part way into the insulative housing, it does not have to be as large as prior art electrodes and therefore material costs may be reduced. The conductive connecting member may comprise a low cost mild steel slug The entire assembly including connecting conductive member and connections with the electrode and conductive lead is preferably sealed within the housing passageway by means of a high temperature adhesive.

The present invention further provides a method of manufacturing an igniter for a fluid burning appliance, comprising the steps of providing an insulating housing having a passageway extending therethrough, inserting an insulated conductive lead entirely through the passageway so that it extends from one end, electrically connecting a conductive connecting member to an exposed end of the insulated conductive lead, electrically and mechanically connecting a second end of the connecting conductive member to one end of an electrode, drawing the assembly of conductive connecting member, connected portion of conductive lead and connected portion of electrode back entirely within the insulating passageway of the insulating housing.

The method preferably further includes the step of sealing the arrangement within the passageway by means of a high temperature adhesive.

The present invention further provides a kit of parts for assembly of an igniter for a fluid burning appliance, comprising an insulating housing having a passageway extending therethrough, a conductive connecting member sized to seat within the passageway and an electrode having one end arranged to extend into an end of the passageway and be electrically and mechanically connected with the conductive connecting member.

The present invention further provides A conductive connecting member for an igniter for a fluid burning appliance, comprising a conductive member sized to seat within a passageway in an insulating housing of the igniter, the connecting member having a first end and a second end and a passageway in each end for receipt of, respectively, a conductive lead for electrical and mechanical connection to the conductive member and an electrode for electrical and mechanical connection to the conductive member.

Features and advantages of the present invention will become apparent from the following the description of an embodiment thereof, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a perspective view from above and one side of a prior art igniter of the type used in domestic ovens and grillers; Figure 2 is a cross-section on line AA of figure 1; Figure 3 is a perspective view from above and one side of an igniter in accordance with an embodiment of the present invention; Figure 4 is a cross section on line BB of figure 3; and Figure 5 is a perspective view from above and one side of a connecting conductive member in accordance with an embodiment of the present invention.

Referring to figures 1 and 2, a commonly used prior art domestic gas oven and griller igniter comprises an elongate stainless steel electrode 1 seated within and passing entirely through a passageway 2 in a ceramic housing 3. An "active" end 4 of the electrode 1 extends from one end 5 of the passageway 2. This end 4 of the electrode is bent downwardly and terminates in a narrow point 6. When a voltage is applied to the electrode 1 a discharge between point 6 and an earth point on the body of the cooker results in a spark to ignite a fluid supply.

Another end 7 of the electrode extends from the opposite end 8 of the passageway 2 and has a roughened or machined surface suitable for connection to an electrical terminal 9 electrically connected to an exposed portion of an insulated conductive lead 10. The terminal 9 therefore provides a conductive connection between the lead 10 and the electrode 1, and a voltage may be applied via the conductive lead 10 to cause discharge from point 6.

This arrangement is prone to the problems discussed in the preamble of this specification. Arcing to earth may occur on the incoming side of the passageway 2, from conductive portions 9 and 7. The connection between terminal 9 and end 7 of electrode may become relaxed due to thermal cycling. The cost of the long stainless steel electrode 1 is relatively high.

Figures 3 to 5 illustrate an embodiment of the present invention.

A ceramic insulating housing 12 has a passageway 13 extending therethrough. A stainless steel electrode 14 extends from one end 15 of the passageway 13 and terminates in a bent portion 16 having a pointed end 17.

A mild steel slug 18 is seated entirely within the passageway 13. The mild steel slug 18 has a first end 19 having a first passageway 20 extending into it.

The first passageway 20 receives the end 21 of the electrode 14 opposite the discharge end 17. The end 19 of the slug 18 is electrically and mechanically connected to the end 21 of the electrode 14 by crimping. The crimped connection is seated entirely within the passageway 13 of the housing 12.

A second end 22 of the slug 18 has a second passageway 23 extending into it. An exposed portion 24 of an insulated conductive lead 25 is seated within the passageway 23 and the end 22 of the slug 18 is crimped to the exposed. portion 24 to make electrical and conductive contact therewith. Again, this contact is also entirely seated within the passageway 13 of the insulating ceramic housing 12.

The entire assembly of mild steel slug 18, exposed end 24 of conductive lead 25 and end 21 of electrode 14 are sealed within the housing 12 by means of a high temperature cement. A suitable high temperature cement is Morganite high temperature ceramic cement.

This arrangement for an igniter has a number of advantages. Firstly, because the electrode 14 does not have to pass entirely through the passageway 13 in the ceramic insulator 12, a smaller electrode is required than in the prior art. The cost of the electrode is therefore reduced. The connective conductive member need only be in the form of a mild steel slug 18, as it is protected by the ceramic housing. A slug of such material is relatively cheap.

Because the entire assembly of connective conductive member, connected portion of electrode and connected portion (exposed end 24) of lead 25 is seated within the passageway 13, there is a much reduced possibility of arcing to earth on the incoming side 26 of the passageway 13. Further, the connections are protected somewhat from the high temperature environment by the insulating ceramic housing and they may therefore be less of a thermal cycling problem for the connections.

The igniter is preferably assembled by the following method: 1. Pass the insulated conductive wire 25 entirely through the passageway 13 in the insulating housing 12 so it extends from the end 15 of the passageway 13.

2. Insert the exposed end 24 of the conductive lead 25 into the passageway 23 in the end 22 of conductive connective member 18 and crimp the end 23 to the exposed portion 24.

3. Insert the end 21 of electrode 14 into passageway 20 within the other end 19 of the conductive connective member 18 and crimp the end 19 to the portion 21 of electrode 14.

4. Draw the assembly of lead 25, connective conductive member 18 and electrode 14 back through the passageway 13, so that the connective conductive member 18 and connections to electrode 14 and conductive lead 25 seat entirely within passageway 13 and seal the arrangement within the passageway 13 by means of a high temperature adhesive. A suitable high temperature adhesive is Morganite high temperature ceramic cement.

The order of at least some of the above method steps may be varied from that given above.

The connecting conducting member is preferably cylindrical and fits within a cylindrical passageway in the insulating housing.

The insulating housing may include a end stop at the end proximate the connection to the conductive lead, so that when the conductive lead and connected assembly is drawn back within the passageway in the housing, the connecting conductive member will be prevented from being withdrawn completely through the housing by the end stop.

The end stop may be manufactured integrally with the insulating housing.

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.

Claims (8)

CLAIMS:

1. An igniter for a fluid burning appliance, comprising an insulating housing having a passageway extending therethrough, an electrode extending from one end of the passageway, an insulated conductive lead extending into the other end of the passageway, and a conductive connecting member electrically connecting the electrode and conductive lead within the passageway.

2. An igniter in accordance with claim 1, wherein the conductive connecting member comprises a conductive body having a first end having a passageway extending therein and a second, opposite end, having a passageway extending therein, the first end receiving an end of the electrode within the passageway and being crimped thereto, and the second end receiving an end of the conductive lead therein and being crimped thereto.

3. An igniter in accordance with claim 1 or claim 2, the conductive connecting member, the portion of the conductive lead extending into the housing passageway and portion of electrode extending into the housing passageway, being sealed within the passageway by means of a high temperature adhesive.

4. An igniter in accordance with claim 2 or claim 3, wherein the conductive connecting member comprises an integrally formed metal slug having two ends of substantially cylindrical form, the two ends being provided with passageways therein for receipt of the conductive lead and electrode, respectively.

5. A method of manufacturing an igniter for a fluid burning appliance, comprising the steps of providing an insulating housing having a passageway extending therethrough, inserting an insulated conductive lead entirely through the passageway so that it extends from one end, electrically connecting a conductive connecting member to an exposed end of the insulated conductive lead, electrically and mechanically connecting a second end of the connecting conductive member to one end of an electrode, drawing the assembly of conductive connecting member, connecting portion of conductive lead and connected portion of electrode back entirely within the insulating passageway of the insulating housing.

6. A method in accordance with claim 5, including the further step of sealing the arrangement within the passageway by means of a high temperature adhesive.

7. A kit of parts for assembly of an igniter for a fluid burning appliance, comprising an insulating housing having a passageway extending therethrough, a conductive connecting member sized to seat within the passageway and an electrode having one end arranged to extend into an end of the passageway and be electrically and mechanically connected with the conductive connecting member.

8. A conductive connecting member for an igniter for a fluid burning appliance, comprising a conductive member sized to seat within a passageway in an insulating housing of the igniter, the connecting member having a first end and a second end and a passageway in each end for receipt of, respectively, a conductive lead for electrical and mechanical connection to the conductive member and an electrode for electrical and mechanical connection to the conductive member.