US1943045A - Thermostatic gas burner - Google Patents

Description

Jan. 9, 1934. E. J. 11-: PAS

THERMOSTATIC. G AS BURNER Original Filed April 21 mvgmon Patented Jan; 9, 1934 UNITED; STATES PATEN Fries 1,943,045 THERMOSTATIC GAS BURNER Edmund J. Te Pas, Lakewood, @hio, assignor to The Cleveland Heater ilompany, Cleveland, Ohio, a corporation of Ohio Original application April 21, 1928, Serial No. 271,798. Divided and this application April 29,

1929. Serial No. scarce 7 1o Claims. (oi. its-dim) The thermostatic valve automatically controls the fuel supply to the heating'burner which is used in connection with the appliance. Appliances of this type are in some cases provided with a constantly burning pilot light which is independent of the operation of the main burner and which is positioned adjacent thereto for the purpose-of igniting the main burner, when gas ,is admitted to it by means of the thermostatic valve.

Another arrangement which is commonly used is that of having a by-pass around the thermostatic valve, to admit at all times a small supply of gas to the burner which in thiscase is in operation continuously. A thermostatic valve is used to increase or decrease the flow of gas to the burner in accordance with the temperature of the liquid with which it is in contact.

' The first named arrangement which contemplates the use of an independent pilot light, usually includes a blue flame gas burner of the atmospheric type in which a certain amount of air is premixed with the gas before combustion takes place. Burners of this type are sometimes referred to as Bunsen burners.

One of the difliculties encountered in the op eration of the Bunsen type of burner .is due to the tendency they have to flash back and burn in the mixing tube when the gas supply to the burner has been cut down below a certain limit. When the burner operates in this manner it produces a dangerous amount of carbon monoxide which may lead to serious results if thispoisonous gas should escape from the appliance.

One of the ways in which flashing back is prevented, is by the use of a. sheet of gauzebe-' tween the burner orifices and the mixing tube. This arrangement is not entirely satisfactory due to the fact that the air which is drawn into the mixing tube usually contains dust and other foreign matter which in timeclogs up the pores or openings in the gauze and in time entirely closes the passages between the burner orifices and the gas and air mixing tube.

This condition is as dangerous as the condition which the application of the gauze or screen was intended to correct, and may result in the escape of unburned gas that might cause an explosion or a case of asphyxiation.

On account of the above characteristics of the aforementioned type of burner, the use of a graduating thermostat with this type of burner has been prevented and a thermostat having a snap action valve is now generally used in this connection and for this purpose. By the use of a snap acting valve the gas burner is either burning at full capacity or the gas supply is entirely shut ed to the burner.

This latter arrangement does not require the use of a gauze burner and practically eliminates the tendency Bunsen burners have to flash back' and burn in their mixing tube. The above arrangement eliminates a great many of the difiiculties encountered in. the operation of the, Bunsen gas burner. It necessitates however the use of a more complicated thermostatic valve which materially increases the cost of the appliance with which it is used and at the same time by reason of the increased number of operating parts, is more apt to get out of order than a control which uses a simple graduating thermostat. v

The type oi control above referred to, wherein the independent pilot light is dispensed with and the main burner is in operation at all times, considerably simplifies the control but is objectionable in that at certain times in the operation oi burners of this type, the burner produces a yellow flame which is apt to cause considerable amount of soot or carbon to be deposited in the appliance. I

. Another objection to both of the above named control systems, is the possibility of extinguishment of either the pilot light orthe reduced flame oi the main burner. In the event of such a happening and ii the thermostatic valve turns on the gas supply to the main burner, there is no means present for its ignition and the full flow of unburned gas escapes from the burner. Serious accidents have occurred under such conditions where it hasbeen attempted to relight the burner when the appliance was full of unburned gas. Again under these conditions gas has escaped from the appliance with serious results. 7

7 One of the objects of my invention is to provide a thermostatically controlled gas burner that automatically cuts ofi the main gas supply to the burner upon extinguishment of the burner flame.

Another object of my invention is to provide a gas burner which may be controlled by a simple graduating thermostat.

Another object of my invention is to provide an improved gas burner that efliciently operates with various kinds of gas and at various pressures.

Another'object of my invention is to provide a main heating burner which does not require the use of an independent pilot light and which incorporates safety control means directly under control of the burner.

Another object of my invention is to provide a generally improved combined fuel cut-off and heating burner that containsa minimum number of parts and has a minimum number of adjustments, that is not apt to require adjustments over long periods of operation, and that is very economical in the use of the fuel used.

Another object of this invention is to provide a fuel cut-of! and burner assembly which form a single operatively connected unit.

Another object of my invention is to provide a combined gas burner and automatic fuel cut-off, in which the cut-off is operative over the complete range of the burner operation, from a pilot flame to the maximum capacity flame of the burner.

A further object of this invention is to provide in a heating burner having a plurality of widely separated flame supporting orifices, a thermolet 11 is provided in static device responsive to the heat of the burner and housed therein and adapted to cut off the fuel supply of the burner upon extinguishmentof the flames of the burner.

With the above mentioned and in view, the invention consists in the novel construction, arrangement and combination of parts, hereinafter'described, illustrated in some of its embodiments in the accompanying drawing and particularly pointed out in the appended claims.

In the drawing exemplifying one form of my improved control;

burner and thermostatic cut-off. Figure 2 is a planview of the burner, taken on section line 2-2 Figure 1.

Referring to Figure 1, thenumeral 1 designates a gas burner that is adapted to be supplied with fuel by way of the conduit 2. A thermostatic valve, having a body portion 4, is interposed between the gassupply conduit 2 and theburner 1.

The valve body 4 is provided with an inlet opening 5, adapted to be connected to the. gas supply conduit 2, and an outlet opening 6, having a bushing 7 for connection with the tube 8 that communicates with the burner 1.

A valve seat 9 is formed in the valve body 4 and cooperates with the valve head 10 to control the flow of gas to theburner 1. An auxiliary outadapted to receive a fitting 12 that is connected the manually operable gas valve 14 which is in communication with the gas supply line 2. The valve l iis provided for the purpose of supplying at times a limited flow of gas to the main burner 1 by way of the bypass 13 for the purpose of opening the valve controlled by the valve head 10.

when my improved cut-oif is used inconnection with a thermostatic regulator as shown in my application Serial No. 271,798 of which this case is a division, 9. limited flow of gas is supplied at all times to the-burner 1 by way of the bypass 13'. when the arrangement is used as a simple cut-of! valve, the valve 14 is normally closed and the gas supply is entirely under control of the valve head 10 and associated mechanism. The valve head 10 is connected to one end of the valve stem 15. Theother end of the valve stem 15 is connected by the adjusting member 16 to a strip of suitable thermostatic metal 1'7. The thermostatic metal 17 consists of a laminated bimetallic strip, one side of which is a metal having a high coefficient of expansion and the other side of which is a metal having a low coeflicient of expansion. r

This type of thermostatic metal is commonly used in temperature responsive devices and, its operation is such that when subjected to changes in temperature it is warped in-one direction or the other depending upon whether its temperature is raised or lowered. The strip 17 is received between a block 32 and fill-in member 33. The block 32 has an opening 18 for a tapered screw 20 to provide a means for expanding the block I 32 and in this'manner securely holding the upper other objects Figure 1 is a side elevational. view'partly in section showing my improved gas the valve body 4 and it is.

. each provide a to a conduit 13. The conduit 13 is connected to possible without them.

end of the thermostatic strip 1'7 in the desired position.

A closure cap of the tube 19. The lower end of the tube 19 is received in the burner casting 36. The lower end of the burner casting is provided with a threaded opening for the reception of the supporting tube 22. The supporting tube is in turn received in an L fitting 23 which is connected at its inlet side to the conduit 8. A- compression 21 is provided for the upper endspring 24 is compressed between the adjusting member16 and the closure cap 25. This spring is provided to when it moves to the left as viewed in Figure 1. The member 16 is held in proper adjustment by the locknut 26 and is threadably received on .one. end of the rod 15. l

. In the open position of is admitted to the burner 1 by way of the conduit 2 the uncovered valve seat 9 and the openings 2'7 which are provided in the valve body 4 for the purpose of supplying gas to the burner 1. The burner is provided in the present case with four radially arranged burner nozzles 28. The burner nozzles at their inner end have a reduction orifice or. central opening 34 which becomes enlarged as .at 35 just before it reaches the laterally drilled rected from the spreader plates 31 merge and furnish a substantially'circular wall of flame. By reason of the air inlet openings 29, when a small amount of gas is burned at the nozzles 28 they small blue flame. a

The wings 30 transmit the heat produced at the ends of the nozzles 28 to the thermostat 1'1. By their use the valve head 10 can be maintained open by a much smaller flame than would be Another. purpose of the side'plates or wings 30 is to shield the flames of the burner nozzles '28 and to prevent them from becoming too rapidly cooled. The efiect of these plates is to promote combustion and to cause the burner 1 to operate at all times with a blue flame. It' has been obassist the thermostatic metal 1'? the valve head 10, gas

terminate in, and

served that when the side plates 30 are not used,

the supply of gas to the nozzles 28, flame that these, burners provide by increasing the small blue when fed a limited supply of gas, changes to a yellow flame, which upon further increase in the III gas flow becomes a blue flame when the gas stream impinges upon the spreader plates 31.

A plausible explanation of the above behavior 01' the burner is as follows:

For very small gas flows sufiicient air is drawn and mixed with the gas by way of the openings 29 to provide a blue flame. ply of gas, a greater amount of gas flows through the "tube 28 and the small openings 29 are not large enough to admit a sufficient supply of air" pinges upon the spreader plates 31 and is spread out in a sheet which exposes a greater area oi the flame to the air and assures the complete combustion oi the gas with a blue flame of intense heat.

At such times when the burner is producing a yellow flame, as would occur at certain times in its operation when the shields 30 are not used, this yellow flame would produce a certain amount of soot or carbon that would be deposited on the heater parts, cutting down their thermal conductivity and lowering the efiiciency of the heater. By reason of the shields 30, my improved gas burner operates at all capacities with a blue flame, providing a very emcient gas. burner which does not produce soot or carbon and which completely consumes the gaseous fuel used.

In starting the burner the valve 14 of the bypass 13 is first opened and a limited flow of gas is supplied to the burner. Shortly after ignition of this gas the burner parts become heated. This heat is conducted to the thermostatic strip 1'? which moves to the left as viewed in Figure 1, urging the valve head 10 to its open position. Gas is then supplied to the burner. by way of the uncovered valve-seat 9, and the by-pass controlling valve 14 is then closed.

By this construction the thermostatic strip 17, when in a heated condition, acts as a spring tending to urge the valve head '10 to its open position. When in a cooled state the thermostatic strip holds the valve head 10 against its seat, closing off the main gas supply to the burner and pre venting the admission of this gas supply to the burner until the burner is reheated in the merener described.

Thus the main burner in this device has a thermostatic valve intimately associated with it to control the flow of gas thereto. This valve provides a positive shut ofi of the gas supply to the main burner at such times as when it would be dangerous to admit such flow to the burner, namely, upon the extinguishment oi flame.

The coil spring 3? acts onone side of the valve head 10 and causes it to follow the movement oi the rod 15 and the thermostatic element 1?. The spring 37, at its end opposite to the valve head 10, is adjustably supported by an abutment 38 that is in turn carried by the adjusting screw 39. A closure cap 4.1 and gasket to prevent the escape of gas from about the screw 39.

The preceding elements provide a simple ad lusting means for the valve; which is effected by increasing or decreasing the tension of the spring 37. Thus by compressing the spring 37, the valve head engages its seat 9 when the strip 17 and burner 1 are at a, higher temperature than would be necessary for the closing of the valve if less force were exerted by the spring.

On increasing the sup-' the burner It the thermostatic metal 17 is in a heated condition, which condition exists only when the burner l is in operation, the valve head 10 is. in an open position and gas is admitted to the burnor 1. Should the burner be extinguished for any reason, the thermostatic metal 17 cools and at the same time shifts and maintains the valve head 10 in contact with its seat 9.

From the foregoing it is apparent that the gas supply of my improved burner is at all'times responsive to, and under control of the heat of the burner. The heat of the burner'is necessary for the opening-of the .valve and in the absence of such heat or upon the extinguishment of the burner, the valve which controls the main gas supply to the burner is in a normally and permanently closed position.

By this arrangement a novel safety means is provided that serves to prevent the escape of unburned gas from the burner, eliminating the hazardous condition which would arise if the burner flame had been accidentally extinguished.

Another advantage of the construction illustrated is that all the operating elements of the system are intimately connected with each other and function as a single unit. This arrangement greatly simplifies the construction of the device and facilitates its installation on the appliance.

My improved bumer and-safety control could be used in connection'with other gas burning appliances where the operation of the burner is automatically controlled by. the temperature of the mediumwhich the burner is adapted to heat.

Furthermore, it is to be understood that the" I particular forms of apparatus shown and def/{ scribed, and the particular procedure set forth, are presented for purposes of explanation and illustration and that various modifications of said apparatus and procedure can be made without departing from my invention as defined in the appended claims.

I claim:

1. In a variable capacity main heating gas burner, the combination of a burner head, mixer tubes carried by the burner head for supporting a plurality of flames at points radially spaced a substantial distance from the center of said burner head, means out of the path of the burner flames and adjacent to the ends of said mixer tubes for conducting heat from the flames supported thereat to the central portion of the burner head, and thermostatic means responsive to the temperature of the central portion of the burner head for cutting off the supply of burner upon its extinguishment.

2.1m a variable capacity main heating gas burner, the combination oi a burner head, mixer tubes carried by the burner head for supporting a plurality oi flames at points radially spaced a substantial distance from said burner head, means adjacent to the ends of the mixer tubes and located alongside the gas stream issuing therefrom and out of contact therewith for conducting heat radiated from the flames supported gas to the at the ends of said mixer tubes to the central 1 portion oi the burner head, and thermostatic means responsive to the temperature of the cen tral portion 01 the burner head for cutting oil the supply of gas to the burner upon its extinguishment.

3. In a gas burner, the combination of a burner head, mixer tubes carried by the burner head for supporting a plurality of flames at points radially spaced in the center of said burner head, means adjacent to the ends of the mixer tubes -for shielding the flames supported thereat, for directin a supply of secondary air thereto and for conducting heat from such flames to the central portion of the burner head, and thermostatic meansresponsive to the temperature of the central portion of the burner head for controlling the supply of gas thereto.

4. In a gas burner, the combination of a burner 'head, mixer tubes carried by the burner head for supporting a plurality of flames at points radially spaced from the center of said burner head, means adjacent to the ends of said mixer tubes positioned alongside of the gas stream issuing therefrom for shielding such flames, for directing a supply of secondary air thereto and for the purpose of conducting heat therefrom to the central portion of the burner head, and thermostatic means'responsive to the temperature of the central portion of the burner head for controlling the supply of gas thereto.-

5. In avariable vcapacity main heating gas burner, the combination of a burner head, mixer tubes carried by the burner head for supporting a plurality of flames at points spaced a substantial distance from the center thereof, means adjacent to the ends of the mixer tubes out of the path of thegas stream issuing therefrom for conducting heat radiated from the burner flames to. the central portion of the burner head, a gas supply conduit communicating with the central portion of the burner head, thermostatic means in said supply conduit responsive to the temperature of the heat conducted thereto from the central portion of said burner head, and valve means actuated by said thermostatic means for cutting off the gas supply of said burner upon the extinguishrnent thereof.

6. In a safety fuel control for a gas burner responsive in its operation to the heat produced by the gas burner, the combination with a burner head, of a series of gas and air mixing tubes extending radially from said head, a radially projecting member arranged below each of said tubes, each member having a surface extending across the path of the gaseous mixture issuing from the adjacent tube for' absorbingheat when the burner is operating at full capacity and having a vertically disposed wall positioned on each \side of the "path of the gaseous mixture issuing 50 from said tubes for a burner is operating at low capacity, and a thermostatically operated fuel control device arranged to have heat conducted to it by said members and to shut off the burner gas supply upon the extinguishment of the burner'flames.

7, In a safety fuel control for a gas burner responsive in its operation to the heat produced by the gas burner, 'the combination with a central gas supply conduit, of a burner head mounted thereon, a series of mixing tubes extending radially from said head in a horizontal plane,

and a member connected to said burner head below each of said tubes having vertically diaabsorbing heat when the posed pairs of spaced walls for absorbing heat when said burner is operating at low capacity and terminating in an imperforate portion crossing the path of-the gas stream issuing from said tube for absorbing heat when said burner is operating at full capacity, said crossing portions being spaced from said tubes and being gradually curved from the horizontal to the vertical, and a thermostatically operated fuel control device arranged to have heat conducted to it by saidmembers and to shut off the burner gas-supply upon the extinguishment of the bumer flames. r

8. In a safety fuel control for a gas burner responsive in its operation to the heat produced by the gas burner, the combinationof flame supporting gas and air mixing tubes and cooperating heat absorbing means for deflecting and spreading the flames issuing from said mixing tubes when gas is supplied thereto at a pressure greater than a predetermined pressure, and heat absorbing means to shield and direct a supply of air to the flames issuing from said tubes for the purpose of maintaining such flames substantially 'blue flame in character when the burner is operated at gas pressures below the stated predetermined pressure, and a thermostatically operated fuel control device arranged to have heat conducted to it by said means and operable to shut off the burner gas supply upon the extinguishment of the burner flames.

9. A safety gas burner for heatinglpurposes adapted for the eflicient utilization and combustion ofa gaseous fuel under varying or fluctuating gas pressures, comprising fuel supplying and distributing means providing a flame supporting ports, a safety fuel control deplurality of .vice for said burner operable to cut off the burner gas supply upon the extinguishment of the burner, and means located out of the path of the burner flames for absorbing heat radiated by the burner flames and conducting it to said device when said bumer is operating under reduced gas pressures, and other means located in the path of each of the burner flames when gas is .supplied to them at relatively high pressures for supplying heat to said device.

10. A safety gasburner for heating purposes adapted 'for the efficient utilization and combustion ofa gaseous fuel under varying or fluctuating. gas pressures, comprising fuel supplying and distributing means providing a plurality of flame supporting ports, a safety fuel control device for said burner operable to cut oi the burner gas supply upon'th'e extinguishment of the burner, andseparate means cooperating with each of the-burner flames for supplying suflicient heat to said device to maintain it in fuel supplying position between the minimum and maximum igas pres es at which said burner is arranged opera v N mmmna'rnrns.

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