US2240950A - Thermostatic fuel control - Google Patents

Description

May 6, 1941. o. w. HAHN THERMOSTATIC FUEL CONTROL.

' Original Filed July 25, 1932 Patented May 6, 1941 THERMOSTATIC FUEL CONTROL Otto W. Hahn, San Francisco, Calif., assigner to Industrial Research Laboratories, Ltd., a com..

ration of Nevada Original application July Divided and this application Decem- 25, 1932, Serial No.

bei' 17, 1934, Serial N0. 757,866

(Cl. 15S-117.1)

8 Claims.

This is a divisional application of my copending application Serial No. 624,505, tiled July 25,

1932, patented December 22, 1936, No. 2,064,909. The invention relates to thermostatic control of iluid fuel supply to burners, particularly fuel gas supply, and has for its objects improved mechanismof this character which will operate directly upon the fuel valve mechanism without the interposition of electric devices, also such mechanism which will be absolutely vfool-proof and will hold the main liuel valve closed when-'no pilot flame is burning. Also a construction of the heat responsive element which will develop considerable movement and mechanical power in heating-andcooling, and insure such operation for years. Other objects and advantages of the invention will appear in the following 'description and accompanying drawing.

In the drawing 4 Fig. 1 is a side elevation, partly in section, showing my improved thermostatic control apparatus on a gas burner.

Fig. 2 is a plan view of the left-hand portion of Fig. 1.

Fig. 3 is an end view of the right-hand end of Fig. 1, partly in section, and showing the gas valves closed.

Fig. 4 is a view similar to that of Fig. 3 but 'showing the main burner gas valve and pilot gas feed open. l

Fig. 5 is a fragmentary section of Fig. 4 as seen from the line 5-5 thereof.

In further detail the drawing shows a portion of a stove or fire box I of any desired heating equipment and within which is one or more gas burners 2 taking the form of pipes with a row of holes 3 on top. These pipes 2 may join a transvalves being shown respectively at I8 and I9 surrounding the respective valve rods which are tted with heads 20, 2l for opening the valves by a rocking cam lever 22 pivoted at 23 to the valve housing, all as will be later explained.

Port I2 leads from the receiving gas chamber I0 through chamber II to the main burner supply pipe 5' and port I3 leads by Way of a passageway 24 to a pilot flame gas supply pipe 25 at the outerend 'of which is a vertically directed pilot flame burner 26 `from the upper end of which :la pilotame 21 is adapted to burn.4

' Port VI3 Afor supplying the pilot is under control oi valve I4 and must open when the main burner port I2 opens,l but besidesport there is another port, l5, for also supplying the pilot'when valve I1 is'open, as this port' I5 also leads'directly to versely extending header or manifold 4 from.

which any number of burner pipes may extend. The burner may take any other form than a straight pipe. Gas is supplied to the header by a supply pipe 5 leading from a box 6 which may contain any desired thermostatic or other automatic control, not shown, for raising, lowering, or extinguishing the ame to suit the heating requirements and from which' box the supply pipe 5 extends to a valve housing 1 forming part of the present invention, and which housing is made separable along the lines 8 and is provided with a .vertical wall 9 forming an outer, I0, and an inner, II, gas chamber ported through the wall by ports I2, I3, closed or opened simultaneously by a spring-actuated valve I4, and ports I5 and I6 closed or opened simultaneously by a spring-actuated valve I1, the springs of the vp.f=r.ssag. ,feway 24. vPort iialso controlled by valve Il leads .toa passageway 28 which supplies gas toa small horizontally Vextending pipe 23 which is openly slotted along its .upper surface and leads to a ring-like burner 30 around the vpilot so that when a llame burns from the ring 3|! it will always bein a position to ignite the pilot when the pilot gas is turned on. 4

The slot 3| in the pipe extends from the ring burner 30 to a point as at' 3l' outside of the stove or re box I so that when the gas is admitted to passage 28 and pipe 29 it may be ignited by a match at 3I' and will travel at once alongthe slot to the ring burner 30 and light the pilot, for the pilot gas will also be flowing in pipe 25 as both ports I5 and I6 are simultaneously uncovered by valve II.

Means is provided for manually opening valves I4 and Il in the rocking lever 22, the pivot pin 23 of which s secured to the lever to rock with it and which pin passes into the valve housing 1 through a packing hub 32 and carries a cam or block 33 which is fast on the pin and so shaped that upon right-hand moving of lever 22 it will Contact head 20 of the stem of valve I4 to open the valve against the spring (as shown in Fig. 4) and when rocked to the left it will permit this valve to close but will then open valve I'I (to the dotted position shown in Fig. 3), and when the handle stands vertical bothvalves will be closed.

This rocking lever 22 is bifurcated at its lower end to form a pair of jaws or lugs, 34 and 35, lug 34 being herein termed the inner lug and lug 35 the outer lug. The lugs are spaced aparton the handle a suicient distance to pass the upper end 36 of a latch 36 which is mounted in such a way that it may be moved inwardly and outresiliently pushed outward at its upper end by a compression spring 4I recessed into both valve housing as well as .the latch (see Fig. 1), and retained in place against the thrust of this spring by a horizontally extending' rod 42 which passes freely through a hole 43 in the latch and through a round pin 44 seated in a notch in the outer side of the latch bar and` has an adjusting nut or nuts 45 at its outer end. The opposite end of the rod 42 is pivotally connected at 46 with the end of one leg of an inverted U-shaped heat responsive element 41 which arches over the pilot light flame and pivotally anchors at 48 at the end of its other leg to a supporting bar 49 which extends rigidly into the re box from the valve housing. The arrangement being such that as the horeseshoe-shaped device 41 opens and closes it will pull or push a rod 42 to thereby either pull the latch 36 inwardly or permit it to swing outwardly under influence of spring 4 I.

. Latch 36 is, however, always free to be manually pushed inwardly due to the open notch in which pin 44 is seated, and to this end is provided with a finger piece or push button 50.

l It will be noted from Fig. l that in the position shown the` latch fulcrums on the upper corner of block 39 very. close to the connection of rod 42 so that a slight movement of rod 42 in an axial direction will result in a relatively large movement of the upper or active end of the latch, but in moving outward the step portions 38 of the latch changes its fulcrum pointfrom the upper corner of block 39 to the lower corner where a small tit 39 projects to help hold the latch in proper position and thus the fulcrum point being shifted further from rod 42 the movement of the latch becomes less with a given movement of the rod, but takes place under greater pressure.

The heat responsive member 41 is of flat chrome nickel steel of horseshoe shape with heavy elongated arms, as shown, and has a curved rowof round holes 5I through it nearer to 'the inner arched line of the horseshoe so as to connect the inner, 41', and outer, 41", curved portions with metal spokes and thereby reduce the heat conductivity between these two portions so thatthe pilot flame 21 in the position shown will maintain the inner arched portion 41' at about a low red heat.

'Ihe lform and material of the heat responsive element vwere developed after exhaustive experiments with various steels and other metals as well as bimetallic constructions, and as a final result the shape with a circular head portion pierced near one edge'with a row of holes was found superior to others in yielding great power and. stability, and the particular metal chosen is a chrome nickel steel containing about 18% chromium and nickel, as this was found to combine a very high scaling point with great resistance to corrosion, a high expansion coeillcient, and a practically complete and quick reversal cycle maintained through a period of years at a temperature of 1500 Fahrenheit.

It was found that with the horseshoe shape of heat responsive element chosen, a substantially uniform heat applied even up to a dull red heat had practically no effect on the latch control, for such application of heat caused a uniform linear expansion of the element with substantially no :outward or leverage movement of the arms, and hence if the pilot ame becomes accidentally, extinguished the latch rod 42 will be at Onceretracted evemwith :the full radiant heat from the main burners or heated fire box of a furnace in which it may be installed, playing freely upon the member, and this will result in the latch 36 being withdrawn from the path of outer lug 35 of lever 22 so that it willpermit valve I4- to close under energy of its spring I8 and thereby close both pilot port I3 and main burner port I2'and extinguish both flames. Continued retraction 'of the rod 42 will pull latch 36 to position in the path of inner lug 34 so that lever 22 could not be swung t'o the right (as in Fig. 4) to open' the main burner valve I'4, but would be freed for swinging in the opposite direction (to the left as per dotted lines in Fig. 3) to thereby cause cam or block 33 to impinge valve stem head 2I and open valve I1 (to the dotted' position in this figure). 'I'he handle 22 would, however, not stay in this position but would fly right back to neutral position (with both valves closed) unless held in open position for valve I I and a match touched to the slotted pipe at 3|' which will instantly shoot a flame along this pipe to the ring burner 41 and thereby light the pilot also being supplied with gas by the opening of valve I1, andthe moment the pilot ignites the element 41 expands and releases latch 36 so that it is pushed out under force of,spring 4| until it touches the inner face of outer lug 36 which then will overlie -it as indicated in Fig. 3, and since this will remove the latch from the path of the inner` lug 34 the lever will be freed to swing to the right for opening the main burner valve I4 as in Fig. 4. This means that the slotted igniter pipe feeder port I6 will be shut o as well as the pilot flame port I6, and hence the slotted igniter pipe and ring burner llame will go out, but the pilot flame will not go out as the other pilot feeding port I3 is opened so quickly that the resi-dual gas within the pilot flame pipe 25 willvtide over this brief instant. As soon as lever 22 is swung to the right to open the 1 ain burner feed and pilot feed I3 latch 36 snaps outward in the path of lug 35 (as in Fig. 4) to lock the hand lever in this position.

It' at any time it was .desired to extinguish both the main burner, and pilot, button 50 may be pushed to force latch 36 against spring 4I until the latch strikes the outer face of lug 34 (which lies just behind the latch as shown. by the dotted position of this lug in Fig. 4)' and lie in the free path between the two lugs so that the large valve I 4 will snap closed.

It will thus `be seen that the lever handle 22 can at first only be moved to the left to permit lighting of the slotted igniter tube, that this ignites the pilot light, that the pilot light releases the lever handle so that it may be swung in opposite direction, and that such a movement at once extinguishes the igniter tube, switches the gas feed of the pilot light and also turns on the main burner which is at once ignited from the pilot. It will also be seen that at any time the pilot goes out the main burner is shut ci! and cannot again be ignited without first lighting the pilot in the manner described.

Having rthus described my improved thermostatic fuel control apparatus it will be seen to be a class of mechanism wherein manyV changes in details can be made without affecting the principles involved, and any such changes as come within the spirit of the invention are intended to be covered in my appended claims.

, I claim:

1. In apparatus of the character described, a pilot flame burner including a fuel feed line therefor, a main burner positioned to be ignited by the pilot flame, unitary manually operated means for successively turning on a fuel supply to said pilot burner and thereafter to the main burner, heat-controlled means normally locking said manually operated means from turning on themain burner fuel supply and released for manual operation l by the heat of saidpilot burner name, and 'spring actuated valvemeans rendered operative by said heat-controlled means upon failure of said pilot flame automatically closing oif both the pilot and the main burner fuel supply, a separate running flame gas igniter tube extending to the pilot for igniting the same, and a valve controlling both igniter tube and pilot fuel feed, a second fuel feed to said pilot arranged to be opened and closed concurrently with the opening and closing of the fuel supply to the main burner.

2. In apparatus of the character described, a

,pilot flame burner including a fuel feed line therefor, a main burner positioned to be ignited by the pilot flame, unitary manually operated means for successively turning on a fuel supply to said pilot burner and thereafter Ato the main burner, heat-controlled means `normally locking said manually operated means from turning on the main burner fuel supply and released for manual operation by the heat of said pilot burner flame, and spring actuated valve means rendered operative by said' heat-controlled means upon failure of said pilot flame automatically closing oif both the pilot and the main burner fuel supply, a separate running flame gas igniter tube extending to the pilot for igniting the same, a valve controlling both ignitei' tube'and pilot fuel feed, a second fuel feed to said pilot arranged to be opened and closed concurrently with the opening and closing of the fuel supply to the main burner, and means automatically closing olf said fuel feed line to the pilot and igniter tube upon opening the fuel line to the main burners and the second pilot fuel feed.

,f 3. Burner fuel control mechanism comprising a main burner and a fuel supply line thereto, a pilot burner positioned to ignite the main' burner and provided with a gas fuel supply line, a spring actuated first valve normally closing ofi' the pilot fuel supply line, manually operated means arranged for opening said valve only while being manually held against itsspring action permitting the valve to close when released, a spring closed second valve manually operable andV normallyclosing off the fuel line to the ing said second valve in open position when opened operative only while said element is heated and released upon its cooling upon ex'- tinguishment of said pilot, and means insuringV a constant flow of gas fuel to said pilot only when said second valve is open.

4. In a construction as set out in claim 3 a handle arrangedfor opening said first valve in `one movement, and opening said second valve in another movement only when unlocked by said heat responsive element. l

5. In a construction as set out in claim 3, said last mentioned means being a separate fuel gas feed line to said pilot burner opened and closed concurrently with the opening and closing of said second valve. 1

6. In combination, a valve housing forming a gas fuel chamber, a main gas fuel supply line connected to said housing, a pilot burner, a main burner, a gas fuel line connecting the valve housing and pilot burner and a gas fuel line connecting the main burner and valve housing, separate valve means within said chamber respectively for the fuel lines, a handle operatively mounted on said valve housing, means interposed between said handle and said valve means requiring two manual movements of said handle for successively opening the valve means for the fuel line to the pilot burner and the fuel line to the main burner to flow of gas from said chamber, spring means normally closing said valve means, a thermostat member responsive to heat developed by the pilot burner so as to move upon the pilot burner being lighted,r and means actuated by movement of the thermostat member for controlling the open position of said valve means and the ow of gas to the pilot burner and to the main burner from'said housing whereby the iiow to both burners is automatically cut off by said spring means upon extinguishment of the pilot burner.

'7. In a construction as set out in claim 3, a manually operated trip for releasing the second valve while normally locked open through the action of said heat responsive means while heated to permit instant closing of the valve under its spring action.

8. In a structure as set out in claim 6, a running name gasigniter tube extending from said chamber to said pilot burner for igniting the same, and said separate valve means within said chamber comprising one valve opening and closing the fuel line to said pilot burner and a fuel line to said igniter tube, and another valve` opening and closing the fuel line to the main burner and a fuel line to said pilot burner.

' o'rro w. Hm.

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