WO2001090649A1

WO2001090649A1 - Gas control valve

Info

Publication number: WO2001090649A1
Application number: PCT/GB2001/002331
Authority: WO
Inventors: Richard Guy Bointon; David John Asplin; Peter Stephen Rolfe
Original assignee: Teddington Controls Limited
Priority date: 2000-05-26
Filing date: 2001-05-25
Publication date: 2001-11-29
Also published as: GB2369427B; GB0204504D0; GB0012956D0; AU5862701A; GB2362706A; GB2369427A

Abstract

A linear action gas control valve e.g. for use with a domestic gas fire is described. Simple construction and smooth variation of main burner level are achieved by incorporating a sleeve valve design where an elongate member (5) may gradually increase the effective passage for gas from a gas supply (20) to a main burner (22). In one end position of the elongate member, gas supply (21) to a pilot flame may be cut off, while in an opposite end position, a main gas flow valve (25, 26), e.g. operated by a solenoid (11), may be opened.

Description

GAS CONTROL VALVE

This invention relates to gas control valves and, more particularly, to linear action gas control valves for use in domestic appliances such as gas fires where it is desirable using a single control to turn the gas fire on or off and to vary the flame level in the burner to a desired degree between a low flame and a maximum setting.

EP-A-0884531 and corresponding GB-A-2326697 discloses a valve of this general type having a valve block and an axially slidable member located in a channel in the block. At one end of the channel is located a solenoid including an actuatable member which carries a sealing member cooperating with a valve seat to shut off gas flow entirely or allow gas to pass from a gas supply into the channel, and a plurality of further valve seats located along the channel which can be successively opened to allow increasing gas flow.

Manufacture of the valve illustrated in EP-A-0884531 is complex particularly as each increase in gas flow requires a closure member to be moved away from a to o t KJ I-¹ cπ o uι o (J1 o cπ z fD <i Ω Ό < Ω CO 01 cr H- 3 < 0 CΩ Ω s! rt fi P⁾ (^ 3 Q (D t-> c Φ < a 3 Ω

I-¹- a CD 0 n Ω 0 CD ro XJ CO P⁾ PJ H 3 0 φ tr H- H- SD 0 ω CO φ a C PJ Φ S-! SD 0 rt I-¹ a 0 Ω a Ω Ω H- 0 a H Hi <! Hi l-i Ω 1 CO P> i-¹ CΩ hi CO H- hi tr CD rt < o a rt rt l-i a P> 0 rt tr 0 Hi JD Hi H- tr > Φ fl Φ Φ H- H- r a hi

H CD H- l-i CD H- H- Φ Φ φ rt l-i (D 0 Φ H H- SD 1 3 H- CO a (D H Φ Φ

H 0 0 H P- Ω O 0 H M _"«• O tr o < iQ H. <! Ω rt Φ t ( a CΩ rt cr Φ H Hi CO fD a tr t-> CD H- rt- a a SD (D f ⁾ H φ H φ t Φ Φ 0 H- a Co H iQ H- h-¹ f H τs rr in M fl a H- SD rt rt O Φ ι-i a (-^■ o ιQ £> ^ rt ⁾ φ O fl> 0

Φ fD 0 H- iQ 0 H t-¹ H- H- <i o Φ < a rt Ω ι-i rt a H- t rt tr t-¹ tr Hi 3 a hi rt Ω a SD a CD Φ <i < P⁾ 0 tr φ Φ a )- Ω 0 Φ H Hi »<J φ f fD CD ^ ιQ iQ • SD P⁾ φ Φ rt Φ (D H Z Φ H rt H- Φ αi 0 •<! hi 0 H-

CD fi. H I-¹ \-> CΩ tr < rt P⁾ 0 CΩ Φ h-¹ Ω SD < 0 a SD CΩ a n P> vQ H- a F- Φ ^ >< Φ < H- φ Hi CO 0 rt H. rt a SD CΩ 3 O Φ ιQ tr tr a (D a CD a 0⁾ P⁾ rt m (H CΩ 0 Φ H- Ω rt H- & CΩ (-^■ rt φ < rt hi fD f CO CD H ιQ Ω O rt •_^ rt 0 P> rt <J 0 tr a H- • 0 <l Φ H Φ rt fD a fD P⁾ 0 0 3 •_* < H- 3 a ct tr Φ a Φ iQ O a Φ Ό O H- SD a a fD Hi l-i H Hi Hi a 0 P⁾ Φ 0 P> • Φ rt 0 Ω &) O H ^ CΩ a H o CD a t-> h rt 0 ιQ τi a »<! rt l-i H ϋ Ω H- Φ O Φ ι <1 tr M 0 fD ^ O rt H- rt PJ ID 3 rt in 0 0 Φ Φ o Ω CΩ f z s: (D CΩ φ

CD SD Ω 3 tr a tr CO H φ H- cr tr P> rt rt CΩ Φ tr rt

CΩ rt Ω rt rt φ β l-¹ rt Ω a Φ fu CO P> H- SD Φ 13 Φ H- Hi H- CΩ Ω CΩ tr rt rt H- O rt 0 KJ Hi a^* rt SD Ω P- O rt iQ a h-¹ Ω • o Φ

Hi CD a o 0 tr Ό PI H Hi 5D Hi Ω Hi CΩ (D H' SD 0 SD tr hi fD

0 H SD a rt Φ P> CO Ω O a H 0 H- H P⁾ H • SD tr H- (D 3 H rt h CD rt fD " CO H-" 0 ≤; 0 H- S a 3 0 CΩ H I-¹ T3 φ CO ⁽-3 Φ ^

H- H- ιQ CD ιQ CO ^ a 3 CΩ 3 CO *ϋ ^ <i 3 ^ CΩ φ TS <1 tr tr CΩ ιQ a 0 cr PJ SD rt rt 3 Φ rt H Φ SD > H- Φ φ CΩ 0 ø τj CO 1 J •_* a FJ O τs O iQ H- l-i 0 0 0 l-i M t3 1-" 3 i P- n Φ ø CΩ o 0

CΩ H h Φ a 0 a H- H C P> CΩ H 0 rt H- H- ^ rt ^ a C rt 3 a Ω CD to Ω l-¹ rt \ a Φ Ω Φ rt Φ CO tr h-¹ CΩ ^ rt f f rt

H- t 2 CD 0 C a Z H H" tr o rt < rt Φ (i> Ω O 0 (D φ H- CΩ H- rt CO tr 1 a CD hi a CD τs H- φ P φ Hi 0 Φ Φ rt tr H- ø H rt 3 a f tr SD

H & _^ rt a τs rt P⁾ cr Hi n I-¹ • SD r ιQ H- tr (D iQ Φ Φ φ rt

Φ Ω CD hi rt H a- CO H σ CΩ H- (D 3 a (-^■ tr CΩ a h-¹ CO CΩ rt a- H rt o ^ H- H- Φ e Hi 0 cr a O ⁾ iQ φ ^ CΩ H rt H- » < CΩ rt

"_" t H- a a Ω ^■ : !-^■ Φ rt φ •_* Ω CO 3 Φ 0 hi SD Φ tr a SD CD a rt ιQ rt a 0 tr M P⁾ φ CO 0 rt SD < a SD ϋ a Φ τs a X < <! o rt 0 Φ z t+ 0 H rt rt a Φ a Φ a rt tr H- rt

H- CD H- < fD CD a rt i-i o> tr ≤; tr fu H- tr rt 3 0 H t Φ to 0 0 a Ω CΩ a SD H 1 φ- tr SD H- a

H H ⁾ fD M a rt Φ t < Ω Φ H- p⁾ Φ a φ H- ««« Hi (D φ ^»<! cr SD ø

0 H H r t a H- H rt tr H < CD H- Φ O l-i Hi a JD H- LQ rt f 0 rt Hi P rt Ω h 3 tr H h-" cr

CD ^■<5 CD 0 H Ω ^ c+ O a H- H- cr tr H" 0 tr rt <i fD Φ H- ><! Φ iQ H- Hi a 3 Φ l-i rt H Ω P⁾ 0 co CΩ φ o a 0 f-i (D 0 X rt hi fD a O Ω 0 fu 0 rt tr 0 Ω 0 a Ω rt Z CΩ ø hi H Hi H- Ω ^ rt to Q 0 hi rt H- < CD tr Φ H 0 l-i 3 SD τs ιQ Φ 3 3 0 o

H- 3 - a Φ CO Φ 3 •υ c iQ 0⁾ a 0 H- Hi tr Φ CΩ g 0 0 Hi

0 rø 0- i CD 1 (D <i rt 0 Ω &> a rt CΩ CΩ SD rt 3 o Hi rt

0 n (D H ι-i cr < id τs H- h a CΩ f H- H- 0 s; a CO Φ rt tr τs rt 0 tr H- CD ø fD P⁾ τs P⁾ 0 (D SD rt s; P- φ τs H- tr O Φ 0

H < CO H. H CO H H rt H H- rt CD CΩ O H Φ CO

CD H- CD h- H- a H- CD H- 0 tr rt ι rt CΩ rt a CΩ Φ φ Hi 0 a 0 CO rt H-

CD H- H a a 0 H- cr a 0 Ω 0 rt a H fD Φ Hi Φ

co Co ro t l-» I-¹

Ui o CH o cπ o Cπ o φ CO Hi H rt < Ω CO 3 3 Z ft 3 Ω Z 3 H *x) SD hi rt O CΩ Ω O 0 3 P H- 0 <i CO fD

0 a 0 H- a 0 fD tr H φ φ H- 0 Φ tr H- ø Φ H Ω fD tr a h-¹ O a rt Φ Cu 3 a fD tr 3 c+ fl -> rt I-¹ fD Φ I B rt s- SD rt 3 a Φ c+ 3 φ rt Φ O rt tr SD Ω Φ H a fl

H Φ rt fD tr < H Φ - tr τs 3 tr ιQ Hi a ua r-¹ Φ τs h-¹ ro τs <l rt

Φ τs a Φ φ φ fD <! φ Φ JD φ 3 φ c+ Φ fD φ 3 φ < Φ φ hi φ rt 0 Φ Φ 1 3 rt 0 0 fl Hi Ω Φ hi hi 0 01 hi Φ SD H tr hi rt Φ rt Φ hi rt l-i Φ f a 0 fD

CΩ F- 0 01 Z rt • 3 CΩ -¹ SD H- 0 fD fD φ fl Φ CO Hi H- tr H- d Z hi H- H- φ 3 SD Φ o Ω O 0 tr O Hi 3 3 < rt tr a Ω 01 CD Hi 3 hi rt H- rt 3 rt H Φ Ό z Hi SD H Hi Hi H 3 01 P fD H- ii f H SD o fD fD H- < rt tr 13 tr H- g TS ω 0 tr 3 O •<! 3 *<J I-- 3 fD O O SD Hi rt <J O a 0 fu tr Φ h-¹ CO Cf" hi ^► hi Φ 01 CO h-¹ SD 3 0 Ω tr < id 3 τs CO fD

Ω rt Φ a a H H Φ fD o a H- Φ SD rt φ < 0 CD Φ Ω 0 H- H- 3 rt SD H rt tr <! 3 H- 1 J M 3 N tr 1 rt tr tr 1- φ 3 S tr CO 3 rt Φ t fl < H

• s: Φ Φ f rt Hi Ω hi 0 0 rt Φ SD Hi Φ 0 Φ 3 01 < 3 H- «» H- ιQ 1 Φ t_l. ro φ tr [D φ 0 φ O (D H- Ω i tr < H- hi φ φ rt SD tr rt rt SD SD ft

H- Z a < O (D (D Φ Φ CΩ H- rt SD h-¹ Φ hi 3 H- H Φ tr fD H- rt τs Φ Ω Ω fD h3 Ω tr O φ 3 3 •υ rt rt a 3 rt H 0 H • rt rt H- H a 0 tr τs ii tr CD P Hi tr tr Φ H SD 3 fD hi φ H- 0 SD Hi ιQ H- ^ O a Φ φ 3 P- a ro hi fD 3 ID

H- a φ o a 0 •<! o H a Hi τs Hi 3 r 3 H- rt fl tr Φ o O a rt ^►ϋ O Ω CΩ a TJ 0 <! τs *< iQ Φ H- fϋ ua 0 rt ιQ 3 H- > fD rt rt < fD h-¹ a rt Z a^* rt SD 3 Hi H- cr hi rt hi Ω hi ø SD rt 3 SD a tr 0 SD Ω μ. CD rt φ 01 tJ 0 tr tr φ fD a Φ H- SD rt tr cr- H- •ϋ 01 ffi tr rt Φ ιQ CΩ rt 01 ro h-¹ tr d tr fl »

H rt Φ M a Ω ιQ SD 01 tr Φ 0 Φ O h-¹ 01 Φ Φ H tr 01 <i Φ SD *_* CD o CΩ H- rt rt fD rt φ hi a hi Φ «_* 3 rt rt φ 01 3 tr ro 01 tr z SD

< fD a _* a TS Ω Φ S! φ rt rt Φ 0 3 ro tr tr φ ro 0 fD iQ tr 3

H- 0 Ω ιQ H fD tr H φ (D τs < rt τs Φ f Φ Φ ιQ rt rt CO o Φ r a SD Φ f fl Hi rt rt Φ hi H- ^ H Ό Φ H- rt H- Φ tr Φ 3 H- SD Φ 3 n CO a 1

Φ Hi 0 τs V rt φ _** H φ H 3 O 3 φ 3 cr (D 01 H CΩ H- CD O SD Φ fD H-

CO SD 0 Φ SD 01 hi rt 3 Φ rt !-^■ Φ a hi Hi rt X Z H- a 3 C lQ rt O a φ rt P> rt ø rt Φ rt φ tr fD H CD Φ M h Hi Φ H- tr 3 0 Ω

SD SD H- H- SD f fD f tr 01 ø hi tr 3 tr 3 o rt Φ SD (-^■ rt H- SD 3 fD φ rt 1 a CΩ 0 rt Ω a φ Φ Φ SD φ t I-¹ Ω rt <! rt 0 tr 3 ιQ 3 fl (-- hi Φ a a H- rt (D n Φ tr Φ Ω tr Φ 0 O tr Φ H- s: Φ Ω SD $1 D rt SD fl

Φ Hi < ø CO fD fl ^ 01 CO £ hi 0 3 3 CD < h-¹ CO τs ^ H- Ω H-

M M 3 φ SD CΩ Z CO φ H- h-¹ φ SD ≤: φ CΩ <! Φ Hi a SD 0 3 tr rt 3 rt 0 Φ rt Φ tr H- CΩ H- a Φ H H H- Φ SD l-i fD f Hi 01 01 H- H H- iQ

H Ω H- H- H- 3 Φ fD I-¹ O rt φ

§^■ I H- H CΩ 3 h-¹ (D 0 I-¹ H- H H- 3 rt SD <

SD (-^■ 0 Ω ^< hi 3 rt < Ω a 3 rt d !*! 3 < 3 O H- rt tr 3 fD SD rt φ 0 a I-¹ tr SD Φ rt tr Φ Ό o SD cr f CΩ CD H- φ id S rt H- rt CD Ω rt Ω 0 hi CO φ fD tr a tr Φ P- Hi rt Φ τs P H- O tr tr Φ 01 fD a 3 • 3 a H CΩ Φ 3 H Φ SD Hi o <! M 3 tr 3 rt SD 3 Φ Ω f o hh rt H- H Φ fD f φ H- Φ φ o rt 0- Ω 3 O O fD h-- ro O τs o fD H

Φ tr O φ KJ 0 Φ M

CT 1 rt tr 0 f hi H- hi τs Φ 0 SD τs rt Ω 3 a <+ Φ rt Φ 01 iQ 3 H 0 φ H- 0 rt * 0 rt Ω a rt hi O tr rt f O 3

^ 3 o Φ tr H- SD H- 0 3 Φ Hi 3 τi tr τs H- 01 f^ 01 tr o fD hi O τs 0 Hi hi Φ 3 01 a 3 iQ hi r-¹ CΩ Φ J SD O O H- rt Φ SD fl 3 O !-^■ Φ H-

Hi H- < •5 ιq iQ O }-• rt H < H 3 <i rt O rt Ω P- a h-¹ 0 3 f

Φ φ rt 3 f M Hi SD rt Ω z φ tr SD H- rt 01 Φ H- o τs tr co CD Ω vQ

(D 0 tr Φ *<! r-> rt rt Φ 0 Φ Φ rt 3 H O 3 H- φ τs H <! fD fD O rt rt Φ ^ 01 0 tr Φ H- O H- ιQ 0 O a fD Hi CΩ h-¹ fϋ rt iQ ra ø rt H- H- s φ 3 Hi Φ a Hi Hi SD 01 H- O 0 SD h-¹ φ Φ Φ hi 0 tr ιQ 3 Ω ιQ SD 3 H rt H- Ω a <i Cu hi

Φ Φ H- rt 0 rt φ fl Φ fD fD rt a Φ (D f fD rt tr Hi 01 rt rt tr Φ O Φ fD fD o Φ Φ 01

insofar as the gas flow is positively shut off even before the pilot light extinguishes and causes the solenoid valve to be released. In constructional terms, this may be achieved by providing an elongate member such as a thin wire or rod extending from the member adapted to close the valve seat, through the slidable member, and slidable through a restriction located in the slidable member, the end of the elongate member being provided with an abutment for engagement with the side of the restriction remote from the valve seat closure member.

An Example of gas control valves in accordance with the present invention are illustrated in the accompanying drawings in which:

Figure 1 is an axial section through a first embodiment of a gas control valve according to the present invention along the lines A-A in Figure 2 ;

Figure 2 is an end view of the valve of Figure 1;

Figure 3 is a perspective view on an enlarged scale of one of the components of the valve of Figure 1, and

Figure 4 is an axial section, similar to Figure 1, of an alternative embodiment.

Referring first to Figures 1 and 2 , the valve is principally constructed of a valve block 1 having an elongate passage running from one end to another and, running transversely to the passage, three bores threaded at their outer ends to enable connection of a main gas supply to bore 20, a pilot burner to bore 21 and a main burner to bore 22. Bore 20 connects to a widened end of the channel running through the block co to ro t H» cπ o cπ o Cπ θl f^ •n tr >τ_ H CO Ω φ Hi H¹ 3 tr" φ F¹ 0 F- t tr F- H 0 F- O

3 a iQ CD 0 i O hi F- Ω Ω o hi H a Z Ω 3 3 hi rt SD 0 hj Φ 3 H iQ O O ti¬

CD H z CD 3 «_* F- SD 3 rt CΩ ro fl F- fl t) tiro tr Z f rt r+ l-¹ tr ro Φ F- to •<! 0 0 SD lP» ro rt SD

00 r F- Hi 01 3 3 ιQ Ω hi

0 ro 01 Ω Φ fl H tr 0

P- Hi •_^ rt rt h-" fD a

3 Ω tr tr F- O a fD a

SD rt o Φ Φ Ό φ Hi fl 01 fl h. X tr a O l-i 01

F- F- CD 3 Φ Hi Φ SD 3 ro Φ ιQ SD tiH 0 fl Cπ a H a M tr ro 0 hi Ω rt §^■ 0

H h-¹ 0 hi 3 3 O O H 3

CD "<J H cr iQ a rt 3

^■ ιQ

H o fD o tr τs fD

I-¹ 01 O K tiHi rt φ h{ JD to rt

*ϋ z ro ro 0 Φ 3 Φ cr SD f SD O CΩ f Z ro Ω rt 3 φ rt 01 tr 3

F- Φ a 01 φ Ω F¹ tT H- Z F- Φ

3 f tr 0 H H- 0 CD O & Ω 1 iQ ro * hi a ii 3 F- tr &

SD c+ φ Ω ιQ Ω φ C h-¹ τs tr tr hi a Φ 01 F- H

0 φ fD SD H rt 3 τs 01 1

Ω i rt cπ fD φ fl hi SD cπ fD rt F- hi F- H Hi rt a 3 rt rt 3 O 3 01 F- O

Φ hi ιQ tr o hi φ Hi iQ O X a f Φ Φ O Φ rt

01 F- rt C Z co CΩ f CΩ fD ^ 3 Φ tr • φ tr φ F- fl 3 φ hi F- 01 l-i H f

K-t. 0 F- fl Ω a < Φ Φ fD 3 rt H cπ tr hi ro M

Ω φ CΩ Ω Φ h 01 fD 0

CD o Hi Z 3 0 rt Hi

3 SD z 3 rt tr fD ø fD F- rt τi fD 01 F- * 3 01 < tr φ H rt (D Ω fl φ H rt h« H F- 01 tr SD F- fD 0 tr rt 01 rt _"« r 3 rt Ω

Φ a a CO a ιQ 01 O f^ hi fD rt tr fϋ rt a

H φ Φ 0 CO τs tr H¹

Φ 01 s * hh z fD τ

3 0 0 F- rt fD hi Ω 01

F- ti^¬ 3 fD

O CO t I-¹ π o cπ o cπ o Cπ a SD h3 tr fϋ CD o CO 3 fD tr a tr Φ 3 H a Φ ro τs fD rt Ω φ H fl O φ Ω Φ 3 o O 3 rt ii fl σ> 3 rt g; F- iQ P F- φ rt

*ϋ ii «_* 3 SD τs O li ø φ

F- li fϋ rt Φ 3 H 3

CO Φ < H SD CD hi CD SD CD d

01 Φ CD H rt H CΩ 01 a 01 ^J iQ F> 3 a O

0 F- a CD hi P- 01 fl Hi ii 0 0 H hh 3 Φ li tr Φ

3 3 Hi SD 0 t SD 0 3 rt fD tia ro t Z Z O tr

F¹ 01 Φ ro H. hi 00 F- a rt ro * τs I-¹ ti3 • Φ

•<! O rt ro tr fD iQ d ro

F- 3 tr ro fD 3 H tr a iQ ro 3 CO fl O Σ> κ> 0

CD KQ fD Hi F' vo a

F" ti3 fD rt 01 rt ιQ α ro fD τs Z ro IT) tr F- SD o F- ro O < F- O 3 rt

SD 3 3 hi ro cQ a Φ ιQ CO CD rt o 3 a iQ hd

[D Φ rt 1- iQ a τs hi tr F- 3

F- fD li τs fD Φ ««• iQ φ 1

3 φ 01 ro 0 ^►ϋ a

01 F- H CO 01 ro H> SD hi cr σ rt 3 Hi F- hi ^» 01 Φ φ cπ H to rt rt li 1 fD O U3 ro a rt fϋ H¹ rt ^ hi tr Ό Cπ

CO Ω O • s ^ ro φ ^►d cr tr O tr 01 Φ Φ fϋ

0 a rt F- -¹ Φ fD F- 3 a a 3" Ω ^ to M H 3 fl

H tiΦ tr F- o O CΩ iQ fl ro *_* 3 •_* a rt ro hi H ια iQ hh 01 tr hi | Φ (D F- fD ϋ ^► Φ cr Hi CΩ P 3 rt O fD

SD 0 rh ^►d Φ 3 Ω O rt hi CD ro τs φ rt ro F- X hi hi 3 rt P. tr rt 01 rø rt P> CD tr Φ tr F- a Ω ro (D hi ro a F" hi rt h-¹

F- F- Φ F- ro 0

CD ιQ 3 3 CΩ Ω hi 3 a H F- CD CD iQ fl fD rt f to tr a Φ 00 rt rt

0 fl &. tr CO tr

Hi

Φ φ

settings of the valve and other adjustable components . Also, if source of pressurised gas is applied to the test point with the gas inlet and outlets to the gas control valve blanked off, any gas leakage from the interior of the valve block can be detected. For this purpose, in the valve illustrated, a further bore is provided in block 1 debouching into the widest but one portion of the channel through the block slightly upstream of bore 22. Its position is just to the left of ring 9 as shown in Figure 1 and a suitable test point sleeve 13 is screwed into the block 1 and sealed with respect thereto. The outer end of test point sleeve 13 is normally blanked off in use by a sealed cap 15 which is removed when it is desired to test the device.

When installed, main gas supply connection is made to bore 20, bore 21 is connected to a pilot burner and bore 22 to a main burner, e.g. in a domestic gas fire. The solenoid 11 is connected to a thermocouple arranged adjacent the pilot burner and designed, when heated, to produce sufficient current to actuate the solenoid and retain valve disc 26 in the position shown in Figure 1, i.e. away from seat 25. A suitable igniter system, e.g. an electric spark generator, is located adjacent the pilot burner and connected to microswitch 2.

The operation of a gas fire incorporating the gas control valve illustrated in the drawings will now be described. In the normal starting condition, i.e. with the gas fire switched off, a spring in solenoid 11 holds valve disc 26 against seat 25 and thus stops any gas flowing from the main gas supply 20. The elongate member 5 can be in any position from slightly to the left of that shown in Figure 1 to its maximum travel to the right. There is simply no gas flow, so it is not relevant where the control elongate member 5 is set. In order to light the gas fire, elongate member 5 is moved to the furthest possible travel to the left as shown in Figure 1. The end of member 5 contacts valve disc 26 and as member 5 is urged to the left, disc 26 may be moved away from seat 25, thus allowing gas to flow from bore 20 via holes 28 into the hollow end of elongate member 5 and out through those holes 29 which are registered with apertures 32 in pilot sleeve 10. As can be seen, there is an annular gap between the portion of the main channel into which pilot sleeve 10 is press fitted and the outer diameter of the beads on sleeve 10, and this enables gas to flow through the annular channel and then into bore 21 and thence to the pilot light. The movement of elongate member 5 to its maximum travel to the left actuates microswitch assembly 2 which, via the circuit to which it is connected, then ignites the pilot flame. Once the flame is ignited, the thermocouple adjacent the pilot flame actuates solenoid 11 to hold valve disc 26 away from seating 25 and accordingly when member 5 is no longer urged to its most leftward position, it is retracted by spring 3 to a position slightly to the left of that drawn in Figure 1 in which gas can still flow from bore 20 through seating 25 and now into the open end of elongate member 5, out through the apertures 29 registered with the apertures 32 in the sleeve 10 and thus maintain the pilot flame lit. in this position, there is no gas flow to the main burner via bore 22 since all of the apertures 29 are located within sleeve 10, or within the portion of the channel shown immediately to the left of sleeve 10 in Figure 1.

If it is desired to light the main burner, member 5 is now moved to the right as shown in Figure 1, thus moving the rightmost apertures 29 into the broader section of the channel in block 1 into which bore 22 debouches. Initially, gas can flow only through a pair of the apertures 29 in member 5, but the flow of gas which then reaches the main burner is sufficient to enable the main burner to be lit by the pilot flame, albeit at a low level setting. As member 5 is moved further to the right, however, more of the apertures 29 emerge from the right hand end of pilot sleeve 10, so more and more gas can flow from inlet 20 to the main burner connected to bore 22. As the member 5 is moved to the right, so ring 9 approaches washer 8 and the maximum setting is achieved when ring 9 abuts washer 8 and nests into the chamfered inner circumference thereof. This end point can be clearly felt by the user of the appliance, but this does not constitute the full extent of the rightwards travel of member 5, as washer 8 is sprung by spring 40 as explained above. It does, however, constitute the maximum flow position with the rightwards set of apertures 29 now all open to the part of the channel into which bore 22 debouches and the left hand end one of the apertures 29 still registered with aperture 32 in the pilot sleeve 10.

The main burner level can be turned up or down at will by moving the member 5 to the right or left respectively.

When it is desired to turn off the fire, the member 5 is moved to the right to engage ring 9 in washer 8 and then moved further to the right with compression of spring 40. This movement causes the left hand end aperture 29 to move past aperture 32, but the dimensions are such that aperture 28 does not reach aperture 32, so, at this point, aperture 32 is sealed and no gas now flows to the pilot burner via bore 21, so the pilot burner extinguishes. Once the pilot burner has extinguished, the thermocouple which it is normally arranged to heat stops providing current to the solenoid 11, so solenoid 11 de-actuates and, because of its own internal spring, moves valve disc 26 to the right as shown in Figure 1 to abut seating 25. As soon as this occurs, the main gas flow via bore 20 is shut off and the main flame connected to bore 22 simply extinguishes. Release of the member 5 moves it back (under the action of spring 40) slightly to the left, but not very much.

Nothing now happens until the member 5 is moved to its leftmost position as described above when someone wants to relight the fire.

Referring now to Figure 4, this shows a similar valve, but with a mechanism for shutting off the main gas flow more positively. Like parts are denoted by the same reference numbers as for Figures 1 to 3, and the general mode of operation is the same. However, in the valve shown in section in Figure 4, the valve disc 26 carries a forward projecting wire 50 which extends slidably through the end of an apertured sleeve member 52 which forms the left hand end (as shown in Figure 4) of member 5. The remainder of member 5 has an axial bore 54 into the end of which sleeve member 52 fits, bore 54 being long enough to accommodate wire 50. The end of wire 50 is broadened and wire 50 is of such length that when a shoulder 53 (which replaces ring 9 of Figure 1) abuts washer 8, the widened end of wire 50 contacts sleeve member 52. As the actuation member is moved further to the right as shown in Figure 4, member 52 entrains wire 50 to pull valve disc 26 on to seat 25, thus shutting off the main gas flow immediately.

A particular advantage of the valve construction in accordance with the present invention is that the relationship between the axial position of member 5 and - li ¬

the gas flow to the main burner may be customised very simply by providing an appropriate pattern of apertures 29 of appropriate size. Because the overall flow passage may be increased in small steps as each aperture comes into the broad section of the channel into which bore 22 debouches, the degree of control which can be exercised can be very fine if called for, and essentially continuous smoother variation of main burner level thereby easily achieved. As can be seen by reviewing the construction shown in the examples of a valve for a gas fire in accordance with the invention illustrated in the accompanying drawings, the manufacture is simple and straightforward, as is assembly. This leads to reliable operation which is sustained over a long service life.

In practice, the right hand end of actuation member 5 outside valve block 1 may be connected to any appropriate actuation knob or lever, either directly or e.g. via a simple mechanical linkage.

Claims

1. A linear action gas control valve for controlling gas flow to a burner, the valve comprising a valve block and an actuation member axially slidable in an elongate channel therein, the channel being provided with lateral branches for gas inlet, pilot gas outlet and main outlet flows, and including a solenoid operated shut-off valve adapted when not activated to engage a valve seat adjacent the gas inlet branch and located to one end of the channel, and wherein the control valve includes a member slidable axially in the channel and adapted as it approaches one end position to displace a member closing the valve seat and as it approaches its other end position to shut off gas flow to the pilot outlet branch, and the member including means cooperating with means set in the valve block to form a sleeve valve whereby the gas flow from inlet to main outlet maybe varied as the relative axial positions of the means constituting the sleeve valve vary over a range of movement intermediate the end positions of the actuation member.

2. A gas control valve according to claim 1 wherein the elongate member consists for part of its length of a hollow tube open at one end and having a number of lateral bores, the hollow tube cooperating with a close- fitting sleeve member located in the channel to form the sleeve valve, and the sleeve member having a port in its wall of size sufficient to enable a pilot flow of gas to pass when the part in the sleeve member coincides with one or more of the bores in the elongate member.

3. A gas control valve according to Claim 1 or 2 wherein the actuation member is fitted with means enabling positive closure of the solenoid valve when the actuation member is moved to the end position which shuts off gas flow to the pilot outlet branch.

4. A gas control valve according to Claim 3 wherein the means for enabling positive closure comprises a thin wire or rod extending from the member adapted to close the valve seat, through the slidable member, and slidable through a restriction located in the slidable member, the end of the wire or rod being provided with an abutment for engagement with the side of the restriction remote from the valve seat closure member.