US2222113A - Thermostatic device - Google Patents

Description

Nov; 19, A1940. c. H MO'RRQW 2,222,113

THERMOSTATI C DEVI CE Filed Oct. l, 1936 -1 INVENTOR CLARENCE H. MORROW A TTORN Y Patented Nov. 19, 1940 UNITED STATES THERMOSTATIC DEVICE Clarence H. Morrow, Shaker Heights, Ohio, as-

signor to The Hotstream Heater Company, Cleveland, Ohio, a. corporation of Ohio i Application October 1, 1936, Serial No. 103,478

1o claims.

This invention relates to thermostatic pilot valve devicesY for fuel burners, particularly burners utilizing gaseous fuel.

One object of the invention is to provide an 5 improved thermostatic pilot device which is entirely safe in the sense that upon extnguishment of the pilot flame all gas supply is cut off,` including not only the supply to the main burner but also that to the pilot burner.

l A further object of the invention is to provide an improved thermostaticV pilot valve device including two cut-oif valves, one for the pilot burner and the other for the main burner, both fully under the control of the pilot thermostat for the l purpose described.

A further object of the invention is to provide an improved thermostatic pilot valve device, including two valves, one for the pilot burner and the other for the main burner, the valve for the 2o pilot burner being directly operated by the pilot thermostat and the valve for the main burner being also controlled by the pilot thermostat, but being of the trigger variety incapable of thermostatic opening when once closed.

A further object is to provide improved thermostatic pilot valve mechanism including a cutol valve for the main burner, said valve being of the trigger variety incapable of thermostatic opening when once closed and said trigger valve 3o being controlled by two thermostats acting in opposition to each other, for the purpose of increasing sensitivity of the mechanism.

A further object of the invention is to provide improved thermostatic pilot valve mechanism specially adapted for use with fuel gas heavier than air,` such as the so-called bottled gas, the mechanism being specially formed so that it can extend into the combustion chamber above the usual enlarged mixer employed with horizontal feed burners, the pilot burner itself being depressed or depending beneath its support so as to lie close to the main jet orices to insure ignition of the main burner name.

A further object of the invention is to provide an improved thermostatic pilot valve mechanism provided with resetting devices lying outside the combustion chamber and so arranged as to be capable of convenient manipulation for the purpose of starting the mechanism into operation.

5g) Further objects ofthe invention are in part obvious and in part will appear more in detail hereinafter.

In the drawing, which represents one typical embodiment of the invention, Fig. 1 is an eleva- 55 tion of my improved thermostatic mechanism,

showing thesame applied to a domestic hot water heater which is shown diagrammatically and in section; Fig. 2 is a longitudinal sectional elevation on the line 22, Fig. 3; Fig. 3 is a sectional plan view on the line 33, Fig. 2, showing the main 5 cut-oil valve in closed position; and Fig. 4 is a det-ail view corresponding to Fig. 3 andshowng the main cut-off valve in open position.

The invention is adapted for use with any device which burns fuel `capable of being con` lo ducted through and being controlled by the valve mechanism to be described, such as gaseous fuel.

It can be usedl with industrial or heating furnaces or boilers or other like devices, but for convenience, and in no sense of limitation, is shown apll plied for use in connection with the ilow of gas to the burners heating a domestic hot water heater, shown conventionally as including an outer casing I enclosing a combustion chamber 2 communicating with an outlet passage 3 to the 20 stack for the products of combustion, said combustion chamber lying beneath the water chamber 4. The Water is heated by any suitable form of main burner, the main burner 5 shown being of the disc form provided with a plurality of jet 25 orifices 6 all supplied from a mixer 'I having the usual tapered enlarged end portion 8 to which air is supplied through the usual pertorations in the rotatable adjusting plate 9. As a general rule the large end of the tapered portion 8 is of so such diameter that its upper portion lies at or above the level of the tops of the orifices 6.

Gas is supplied to the main burner 5 from a supply main II) by way of an emergency cut-oil? valve marked generally II, said valve being con- 35 trolled by the thermcstatic pilot mechanism to be described and including a pilot burner marked generally I 2. From the main cut-off valve II the gas flows by way of a pipe I3 and an ordinary `hand operated gas cock I4 to the mixer l and o thence into the main burner.

While the gas supply for the main burner may be delivered from the main IQ directly to the cutoff valve I I, the hand operated gas cock I4 being 'depended upon to adjust the size of the main 45 burner flame and a thermostatic pilot being de pended upon to close the cut-oi valve in case the pilot burner goes out', the invention may also be utilized in cases where automatic regulation oi.' the main burner llame is desirable, the drawing showing for this purpose an ordinary thermo- 4statically operated valve I5 in the supply line between th'e main I0 and the valve II, said thermostatic valve being provided with thermostatic elements I6 extending into the water chamber l and 55 sensitive to the temperature of the water therein. 'Ihis thermostatic valve mechanism may be of any suitable form, either snap acting or of the gradually acting type and for convenience may be assumed to be a graduating thermostatic mechanism and may be assumed to be of the same general form and arrangement as the valve mechanism illustrated in my patent for Thermostatic valve, No. 1,679,165, granted July 31, 1928, to which reference may be had for the details, description whereof is here unnecessary.

The gas supply for the pilot burner I2 preferably is led to said burner by channels independent of the main cut-off valve II, so that the pilot burner will burn independently of whether the main cut-oft valve II is open or closed. Also, when a thermostatic regulating valve, such as the valve I5, is employed, the supply for the pilot burner is made independent of said therrnostatic regulating valve so as to be unaffected by its operation. In the arrangement shown, the supply for the pilot burner I2 comes directly from the main I0 by way of a pipe Il provided with a hand operated gas cock I'Ia. by which the size of the pilot burner may be adjusted. In the supply line to the pilot burner is also included an automatic controlling valve for said burner, marked generally I8 and which will be described more in detail hereafter.

For convenience, the operation, both here and later, will be described to include the regulating thermostat I5, although such valve is unnecessary, as before referred to. Assuming all valves open, valves I4 and IIa to the proper amount to regulate the maximum height of the main and pilot burner llames, the effect of the thermostatic element I6 is to regulate the main burner flame by increasing or diminishing the supply of gas or by shutting `ofi the supply altogether, so as to maintain the water in the chamber 4 at uniform temperature. However, if at any time or for any reason, such as the effect of back draft, both the main and pilot burners go out, then the thermostatic pilot mechanism operates to control both of the valves II and I8, permitting valve II to move to its closed position and causing the valve I8 to close, thereby entirely shutting ofi all supply of gas and making it necessary to l again reset the mechanism and light the pilot burner in a manner to be later described.

The main cut-olf valve yII may be of any suitable forrn but preferably is a trigger valve normally tending to move to closed position and incapable of automatic or thermostatic movement to open position when'once closed, and normally held in open position by a trigger. For convenience, and in no sense of limitation, the valve shown in the drawing for this purpose is of the same form shown in my prior patent for 'Ihermostatically operated emergency gas shut-oil valve for hot water heaters, No. 1,991,863, granted February 19, 1935, to which reference may be had for description of the details, which are here unnecessary except to say that the valve mechanism includes a slide valve I Ia normally moved toward closed position by a spring I9 and provided with a spring holding lip 20 arranged to cooperate with a trigger, such as the projecting end of a trigger rod 2|. 22 represents the head of a resetting device enclosed within a cap 23. By removing the cap the head may be pressed in manually against the spring i9 to move' the valve to open position, in which it may be held by the trigger, as shown in Fig. 4, until automatically released in the manner hereafter described.

The gas supply for the pilot burner is led by way of the pipe I'I and valve Ila to a chamber 24 located within an extension of the casing 25 of valve II, and from which chamber the gas flows to the channel of a tubular member 26 connected at its outer end to a tubular mixer 21 having air supply ports 28 and in the end of which is mounted a suitable burner head 29 provided with gas conducting slots 30. Communication between chamber 24 and the channel oi tube 26 is controlled by the valve I8, which includes a valve member 3I of hemispherical form provided with grooves or ilattened portions 3Ia for gas passage cooperating with a ported seat 32 in one end of a hollow member 33 screwed upon a block 34 which in turn is screwed upon the end of the tube 26. Member 33 slides in a portion of the chamber 24, and leakage from said chamber is prevented by a packing 35 tightened by a packing nut 36, the tube 26 having sliding motion within said packing. Valve 3l is held to its seat by a compression spring 31 and to said valve is connected the trigger rod 2l. So that the valve may be self-accommodating to its seat, the connection 38 between the valve member and trigger rod is of the ball and socket variety. Also, tubular shell 33 preferably is smaller in diameter than that portion of the chamber 24 in which it slides and is provided with a spherical portion 39 closely tting the cylindrical surface of the chamber and enabling the shell 33 to take a slightly askew position in said chamber as may be necessary to take account of inaccuracies in workmanship, misalign'ment oi parts, and so on.

The thermostatic controlling eilect is produced by the effect of the pilot llame upon suitable thermostatic devices. .The main thermostat is shown as a bent bimetallic member 40 secured by a screw 4I to a block 42 driven into the end of a tube 43 made of relatively expansible ma terial such as copper, brass or the like. The free end of the bimetallic member 4B is bent to form a nger 44 which enters and is e. fairly close t in a groove 45 in the pilot burner mixer 2'I and the bimetallic member is of such construction and is so arranged that when heated the finger 44 moves to the left or to the dotted line position, Fig. 2, whereas when member 4d is cooled nger 44 moves to the right or to the full line position, Fig. 2.` This motion is taken advantage of to control valves I3 and II.

Fig. 4 shows the position of the parts when the pilot ame is burning and the pilot burner and thermostat are hot. Tube 26 has been moved to the left by movement of thermostat 40 to the dotted line position in Fig. 2. This motion is suilcient to cause the end of valve member 3l to engage the adjustable plug 46 in which rod 2I slides and to permit the valve seat 32 to move away from the valve member, so that 'the valve I8 is open and gas flowing into chamber 24 flows past the valve and into the channel of tube 2S and thence to the burner. -At the same time the end of the trigger rod 2I projects into the chamber of valve II and serves as a trigger to hold said valve open. The parts remain in this condition solong as the pilot burner is burning. If the names of both the main and pilot burners go out for any reason, the parts cool, whereupon thermostat 46 is flexed to the full line position, Fig. 2, moving the burner and tube 26 to the right. The rst effect of such motion is to permit valve IB to close by movement of its seattoward the valve member, whereupon valve member 3| and the rod 2| partake of theV motion of tube 26 until the trigger is withdrawn from be- 5 neath the spring lip 2U and valve snaps to closed position by the effect of its spring I3, thereby shutting off all supply of gas to both'the pilot and main burners.

To restore the parts to operating condition it 1o is necessary to reset them by hand. For this purpose I provide` means for manually moving rod 26 to the left in Fig. 2, such as a lever 41 having an eye portion 48 loosely surrounding the rod 26 `adjacent acollar 49 therein, one end of l5 the lever having a'projection 5|) entering an opening in the tube 43 and the other end of the lever extending out through a longitudinal slot 5| of said tube and bent to form a finger operating portion. By pressing upward in Fig. 2 on the iinger operating portion 52, the lever moves the rod to the left, thereby opening valve I8 and causing the trigger tc project into the chamber of valve |I. Cap 23 being removed from said valve the resetting button 22 is pushed in soas t0 25 open the valve and move lip 20 to holding position beyond the triggenas shown in Fig. 4. Upon opening of valve I8 gas flows to the pilot burner, which may be ignited to burn and thereby heat. the thermostat so as to maintain the :lo parts in the position to which they have been moved manually. `Of course, during the ignition of the pilot burner the cock |4 controlling the supply to the main burner is preferably closed to avoid explosion. After the pilot burner is 35 ignited and stays lighted, the cock |4 may be opened to permitthe main burner to burn..

The second thermostatic means affected by the pilot flame comprises the two thermostatic elements 43 and 26, the first of which is relatively 4,0 expansible, being made of coppennbrass or the i lilre, while the tube 26 is made of relatively inexpansible material, such as steel. The relative expansion between members 26 and 43 is taken advantage of to increase the sensitivity of the qui devices. As to these two members, when the parts are heated or the temperature rises, the tube 43 expands and carries with it, to the right in Fig. 2, the relatively inexpansible tube 26 together with the partsvconnected to it, including valve seat 32, but not sufficiently to close the valve i It. In other words, the effect of this thermostat is in opposition to that of the bimetallic member 4U, but the amount of movement produced by member 4|] is considerably greater than that 5s produced bythe consequent action of members 2li, t3. Rise of temperature, as when the pilot name is first ignited, or drop of temperature, as when the pilot flame` goes out, are more immediately effective upon thermostat 40 than upon 6@ the tubes 26, 43. As a consequence, when the pilot flame is first ignited, the tube 26 and trigger rod 2| are moved the maximum distance to latching position, after which the effect of the thermostat 26, 43 is to partially return the parts @5 toward unlatching position. Consequently, when the pilot flame goes out the contrary effect, including release of the trigger, occurs more quickly than it otherwisewould, and the device is responsive very promptly to an abnormal reduction oi temperature.

` It will be observed that pipe 26 which delivers gas to the pilotburner is bent downwardly intermediate its ends and extends outwardly through the slot 5| in tube 43. The purpose of such construction is to locate the pilot burner appreciably below the body portion of tubo as. As a oonsequence, tube 43 may lie just above the larger por- `tion of the mixer 8 and nevertheless the pilot burner will lie at a level closely adjacent the `jet orifices of the main burner 5 and therefore gni- 5 tion of the flame of the main burner is assured even though the gas used is heavier than air and tends to fall rather than rise when it issues from the orice.

53 represents a combined shield and heat trap, 1o consisting of a sheet metal member having a body portion 54 anchored with the thermostat 4U beneath the head of screw 4|, and provided with depending side wings 55 forming an inverted cup, the free end of the metal being bent downwardly lts into the form of a tongue 56 extending over and` beyond the curved portion of the thermostatic member 40. This device has several functions. In the first place it is a mechanical guard partially covering the thermostatic element and p0 burner head 29 and protecting them from mechanical injury. Secondly, it serves as a water shed to drain away from the same parts any water of condensation that might otherwise collect upon them. Also, the inverted cup form oi 25 the device, together with the mass of metal which it locates just above the pilot flame serves to collect and hold the heat oi' the pilot burner, thus smoothing out the thermostatic action. Without this shield a considerable portion of the 30 heat of the pilot flame is carried away with no effect upon the thermostat 4|) whose movement is therefore not complete, the result being that if the pilot jet is adjusted to suitable small `name size when the pilot burner alone is burning, then 35 when the main burner is lighted the additional intense heat supplied further opens the valve 3|, 32 and the pilot ilame burns with greatly increased size and so continues to burn for some time after the main burner goes out. In other words, the pilot burner Valve is not fully operative by the pilot burner alone. With the shield in place, however, the pilot burner oriiice 5l may be made of reduced' size and the line pressure back of it increased by greater opening of valve lla. 'rho pilot camo is thon adjusted to suitable size 45 and its heat is more effectively trapped by the additional mass of metal of the shield 53and its cup effect, so that with the pilot ame alone valve 3|, 32 is fully opened and ignition of the main burner has no additional effect.

The construction described supplies a simple sensitive and completely safe ther'mostatic pilot device capable of convenient setting by the operator when starting it in operationand which directly actuates a valve controlling the gas flow to the pilot burnerand controls a trigger actuated valve supplying gas to the main burner, both supplies of gas being fully shut olif when the pilot flame goes out for any reason whatsoever. The mechanism is adapted for use in connection with either hand operated or automatically controlled burners and can be applied to a burner for heating any kind of device.

In the drawing the valve mechanism is shown 55 arranged for connection to vertically extending supply and discharge gas pipes. In other words, the gas goes through the valve from top to bottom. If desired, however, the parts may be very readily accommodated to situations in which the lll gas pipes extend horizontally, either from left to right or vice versa. Byunscrewing or loosening the flange nut which clamps the tube 43 to the extension of the valve casing, tube 43 together with the pilot burner pipe 26 and tube 33 may 715 be rotated 90 around the axis of tube 43, either to the right or left, and then reclamped. The parts in the new positions adapt the device to horizontally extending pipes, but the pilot burner, nevertheless, lies below the thermostatic element 40 and closely adjacent the burner 6, as will be readily understood.

What I claim is:

1. In mechanism having a main burner, having a control valve therefor biased toward closed position and having a trigger for holding it open, having a pilot burner, and having a valve therefor; primary thermostatic means connected to operate the pilot burner valve and the trigger of the main burner valve in valve closing direction upon extinguishment of the pilot iiame, and secondary thermostatic means adapted to partially close the pilot burner valve by the heat effect of the pilot flame.

2. In mechanism of the class described, two thermostat members having different coeihcients of expansion and mounted for relative movement, coacting valve control parts operatively connected with said members respectively, and a separate thermostatic device carried by one of said members and operatively connected with the other of said members for varying the relative position of said members responsive to temperature changes of said device.

3. In mechanism of the class described, a thermostatic member, a rod supported for relative movement longitudinally of said member, said member being more expansible by heat than said rod, whereby relative longitudinal movement occurs between them upon a change of temperature, a burner carried by said rod in position to heat said member, a fuel supply for said burner including a valve having a control part movable by said rod, a bimetallic device in position to be heated by said burner and operatively connected between said member and rod in a manner to cause relative longitudinal movement between them opposite to the relative movement caused by the expansion difference between said member and said rod, said bimetallic device being more quickly responsive to changes in temperature than said thermostatic member, whereby upon heating or cooling said bimetallic device quickly moves said valve control part in one direction and thereafter by action of said thermostatic member said control part is moved in the opposite direction so that it is more sensitive to the next temperature change of opposite character.

4. Mechanism as in claim 3, wherein said rod is a hollow tube providing communication between said valve and said burner.

5. In mechanism of the class described including a main burner and a pilot burner forl igniting it, a valve casing having a chamber provided with a supply opening, a hollow member slidable in said chamber and provided with a cavity and a valve seat, a valve within the cavity of said member cooperating with said seat, the valve casing having a valve abutment, a tubular member communicating with said cavity and adapted for connection to said pilot burner, thermostatic means responsive to said pilot burner for actuating said tubular member to open and close said valve, a second valve in said casing for controlling said main burner, means normally tending to close said second valve, a trigger holding said second valve against closing, said trigger having an operative connection with said first valve, whereby cooling of said thermostatic means upon accidental extinguishing of the pilot burner will cut ofi the supply to both burners.

6. In mechanism of the class described, a main burner control valve, a pilot burner control valve, parts operatively connected with both valves for concurrently causing both of said valves to remain open or for concurrently causing both of said valves to close, two thermostatic devices 0peratively connected with said parts for moving the latter in opposite directions to cause valve opening and closing, one of said devices being more sensitive to temperature changes than the other, the less sensitive of said devices having an operative connection with said parts to cause yunder given heating conditions movement of said parts in one of said directions, and the more sensitive of said devices having an operative connection with said parts for causing movement of said parts in the opposite direction upon continuation of the same heating conditions, the movement caused by said less sensitive device being less than the movement causedby said more sensitive device.

7. In mechanism comprising a burner and a valve controlling a fuel supply thereto, the combination of two relatively movable parts for controlling said valve, two relatively movable thermostatic elements having different coelcients of expansion, said elements being connected one to each of said relatively movable parts respectively, and a lever for moving one of said parts independent of the effect of heat on said elements, said lever having a fulcrum on one of said elements and a portion ofsaid lever engaging the other of said elements.

8. In mechanism of the class described, a valve casing having a chamber provided with a supply opening, a hollow member slidable in said chamber and provided with a cavity and a valve seat, a Valve within the cavity of said member cooperating with said seat, a spring urging said valve toward said seat, the valve casing having a Valve abutment in the path of valve movement, a tubular member communicating with said cavity and operatively connected with said hollow member, and means for moving said tubular member to cause said valve to strike said abutment to open said valve.

9. The combination of claim 8 including a second valve normally urged toward closed position, a trigger for holding said second valve open, and an operative connection between said valves for moving said trigger to release position by movement of said iirst named valve away from said abutment.

10. In mechanism of the class described, a burner control valve, parts associated therewith having a valve-open position for retaining the valve in its open position and a valve-closed position wherein they permit closing of said valve, two thermostatic devices operatively connected with said parts for moving them to said valveopen and Valve-closed positions, one of said devices being more sensitive to temperature changes than the other, the more sensitive of said devices having a connection with said parts for causing movement of said parts toward valve-open position upon heating of said device, and the less sensitive of said devices having a connection with said parts for causing movement of said parts toward valve-closed position upon heating of said device, the movement of said parts caused by said less sensitive device being less than the movement of said parts caused by said more sensitive device. CLARENCE H. MORROW.

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