US1842328A

US1842328A - Thermostatic valve and gas burner

Info

Publication number: US1842328A
Application number: US271798A
Authority: US
Inventors: Pas Edmund J Te
Original assignee: Patrol Valve Co
Current assignee: Patrol Valve Co
Priority date: 1928-04-21
Filing date: 1928-04-21
Publication date: 1932-01-19
Anticipated expiration: 1949-01-19

Description

Jan. 19, 1932. E. J. TE PAS THERMOSTATIC VALVE AND GAS BURNER Filed April 21, 1928' I the tendency they have Patented Jan. 19, 1932 UNITED STATES PATENT OFFICE OHIO, ASSIGNOR TO THE PATROL VALVE COMPANY,

.A. CORPORATION OF OHIO THERMOSTATIO VALVE AND GAS BURNER application filed April 21,

This invention relates to gas burning appliances and in particular automatic safety fuel control systems for use in connection therewith.

It is the customary practice to control liquid heaters of the type referred to in this application, by means of a thermostatic valve in contact with the liquid which is being heated. 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 idependent of the operation of the main burner and 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-pa-ss around the thermostatic valve to admit at all times a small supply of gas to the burner which in this case is in operation continuously. A thermostatic valve is used to increase or decrease the How 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 operation of the Bunsen type of burner-is to flash back and burn in the mixingtube when the gas supply to the burner has been cut down below a certain limit. \Vhen the burner operates in this manner it produces a'dangerousamount of carbon monoxide which may lead to serious results if this poisonous gas should escape from the appliance.

One of the ways in which flashing back 1928. Serial No. 271,798.

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 snap action valve is now generally used in this connection and for this purpose. By the use of a sn ap acting valve the gas burncr is either burning at full capacity or the gas supply is entirely shut off 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 difficulties encountered in the operation of the Bunsen gas burner. 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 graduatingthermostat.

The type of 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 of burners of this type, the burner produces a yellow flame which is 115 1 from the appliance with serious results.

aptto cause considerable amounttofsoot or carbon to be deposited in the appliance.

.= Another objection to both of the above named control systems, is the possibility of extinguishment of the reduced flame of the main burner. In the event of such a happening and if the thermostatic valve turns on the gas supply to the main burner there is no means present for its ignition" and the escapes from the burner. have occurred under such conditions where it has been attempted to relight the burner when the appliance was full of unburned gas. Again under these conditions gas-has escaped One of the objects of my invention is to provide a thermostatically controlled gas burner that automatically cuts off the main gas supply to the burner upon extinguishment of the burner flame.

Another object of my invention is to provide a gas burner control which is operated by a graduating thermostat of a greatly simpli ed design.

Another object of my invention is to provide an improved gas burner that efficiently operates with various kinds of gas and at various gas 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 an automatic and safety control for appliances of the type described in which the gas flow to the main burner is controlled by a single gas valve, responsive to the temperature of the liquid which is being heated and independently res onsive to the operation of the main heating urner.

Another object of my invention is to provide a generally improved control and heating burner that contains a 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 control and burner assembly which form a single operatively connected unit.

A further object of this invention is to pro-. vide a cooperatively associated burner and thermostatic control in which the flow of gas to the burner is controlled by a single valve head that has independent opening means and independent closing means that operate to safely control the flow of gas to the burner.

- With the above mentioned and other objects in view, the invention consists in the novel construction, arrangement and combi nation of parts, hereinafter described, illuseither the pilot light orfull flow of unburned gas Serious accidents trated' in some of it's'embodiments in the aceompan'ying drawings. and particularly pointe'dout in the appended claims.

The present invention includes certain features common to my copending application Serial No.160,747 filed January 12, 1927, and applications Serial Nos. 271,7 99, 271,800, 271,801, 271,802 and 271,803 filed April 21, 1928, as well as application Serial No. 3,333 filed byL. F. Doen January 19, 1925 and application Serial No. 123,561, filed by W. J. Snow July 19, 1926, and such common features are hereby disclaimed in the invention to which the present application relates.

. In the drawings exemplifying one form of my improved control; Fig. 1 is a side eleva- 'tional view partly in section showing my improved control applied to a gas fired liquid heated. Fig. 2 is a plan elevational view taken in section line 2-2 Fig. 1, showing the construction of my improved burner.

The arrangement shown in Fig. 1 is intended to illustrate an automatically controlled gas fired storage liquid heater. Several of the well known parts of the heater are not shown as these elements, such as the supporting stand, casing, vent, etc., are conventional and well understood and do not form a part of this invention, which is confined to the gas burner and the automatic safety control used in connection therewith.

The reference numeral 1 indicates a storage vessel that is adapted to serve as a container for water heated by the gas burner 2, that is positioned below the container 1. Gas is supplied to the burner 2 by way of the main supply conduit 3 under control of a thermostat 4. The thermostat 1 is provided with an expansion tube 5, that projects into the container 1 and is responsive to the temperature of the liquid therein and with which itis in I contact.

The tube 5 is made of a material having a relatively high coefficient of expansion as compared with the rod 6 which it encloses. The expansion tube in thermostatic devices of this sort is usually made of copper and the rod 6 is ordinarily made of 36% nickel steel commonly referred to as invar steel or it may be made of porcelain or carbon. Any of the above rod materials have a considerably lower coeificient of thermal expansion than the copper tube 5. The rod 6 is in contact with the inner end 7 of the tube5 and at its outer end is in contact with the compounding or fulcrum lever 8 of the thermostat. At its fulcrum point the lever S issupported by an adjustable knife edge bearing 9, which is rotatably mounted in the adjusting screw 10.

The adjusting screw 10 is in threaded engagement with the fulcrum lever housing 11 at the point 12 and is provided with the locknut 13 and closure cap 14 which serve to maintain the element 9 in the desired position. The housing 11 is in threaded engagement with a coupling member 15 that is internally threaded at 16 for reception of the thermostat tube The member 15 is carried by the threaded bushing- 17 which in turn is threadably mounted on. a tube 18 that is carried in a similar manner in theside of the container 1 at the point 19. The inner diameter of the tube 18 is somewhat larger than the outer diameter of the thermostatic tube 5 which allows the liquid from the tank 1 to contact with practically the whole length of the tube This arrangement makes the thermostat more sensitive and permits the use of a thermostat having a relatively long tube as compared with the diameter of the tank or container into which it projects.

By reason of the differential thermal ex pansion of the tube 5 and the rod 6, increase in temperature of these elements will cause the end of the rod 6 that is in contact with the lever 8, to move to the right as viewed in Fig. 1. In like manner a lowering of the temperature of the tube 5 and the rod 6, will cause the end of the rod 6 to move to the left. his movement of the rod 6 is transmitted to the fulcrum lever 8 and is multiplied many times at the lower end 20, by reason of the relation of the fulcrum point with respect to 42 the point of contact of the rod 6 with the lever 8. 4

A pair of rollers 22 are formed on the end of the plunger 21 and are adapted to contact with the forked end of the lever 8. A compression spring 23 holds the rollers 22 in contact with the end of the lever 20. An adjusting screw 24 is.provided to adjust the tension of the spring 23. The adjusting screw 24 is provided with a locknut 25 and a cap 26 which serve to hold the screw 24 in the desired position.

The housing tube 11 is suitably received in an L fitting 27 which is in threaded engagement with the bearing member28. A valve body 30 is mounted upon the bearing member 28. is in communication with the gas supply conduit 3 and the side outlet 32 is connected by means of a reducing coupling 33 to the conduit 34 which leads to the burner 2.

A valve seat 35 is formed in the valve body 30 and cooperates with the valve head 36 to control the flow of gas to the burner 2. An auxiliary outlet 37 is provided in the valve body 30 and has a fitting 38 that is connected to a conduit 39. The conduit 39 is connected to the gas valve 40 which is in communication with the gassupply line 3. The gas valve 40 is provided for the purpose of supplying at all times a limited and controllable amount of gas to the burner 2.

The valve head 36 is connected to one end of the valve stem 41. The other end of the valve stem 41 is connected at 42-to a strip of The inlet end 31 of the valve body th thermostatic metal 43. The thermostatic metal 43 consists of a laminated bimetallic strip, one side of. which is a metal having a high coeflicient of expansion and the other side of which is a metal having a low coefficient of expansion.

This type of thermostatic metal is commonly use in a large number of temperature responsive devices and its operation is such that when subjected to changes in temperature it 1s warped in one direction or the other depending upon whether its temperature is raised or lowered. The strip 43 is received In the block 44 that is securely held in the The block 44 is provided with a tapered screw 46 to provide a means for expanding the block 44 and in this manner securely holding the upper end of the thermostatic strip 43.

A closure. cap 47 is provided for the up per end of the tube 45. The lower end of t e tube is received in the burner casting The lower end of the burner casting 47 is provided with a threaded opening for the reception of the'supporting tube 48. The supporting tube 48 is received in an L fitting 49 which is connected at its inlet side to the conduit 34. A compression spring 50 is compressed between the adjusting member and the closure cap 51. This spring is provided to take up any play between the forked end of the thermostatic metal 43 and the annularly grooved member 42, which is held in proper adjustment by the locknut 52.

The thermostatic metal 43 isslotted at its lower end for reception of the adjusting member 42. In this manner the thermostatic metal straddles the adjusting member 42.

he member 42 is threadably received in the end of the rod 41. A lock-nut 52 is provided to lock the rod and the member 42 in the desired position and provides an adjustment means therefor.

In the open position of the valve head 36. gas is admitted to the burner 2 by way of the conduit 3 the uncovered valve seat 35 and e openings 53 which are provided in the valve body 30 for the purpose of supplying gas to the burner 2. The burner 2 is provided in the present case with four burner nozzles 54. The burner nozzles at their inner end have a reduction orifice or central opening which becomes enlarged as at 61 just efore it reaches the side inlet air openings 5.

The burner tubes 54 are partially enclosed. by the wings 56 that form a part of the burner casting 47. The wings 56 terminate in and support deflector plates 57 that are shaped to deflect the flames from the burner tubes 54 in an upward direction. When the burner is operating at full capacity, the four flames from the spreader plates 57 merge and furnish a substantially cylindrical wall of flame. By reason of the air inlet openings 55, when a small amount of gas is burned at the burner nozzles 54 they each support a small blue flame.

The purpose and function of the side plates or wings 56 is to shield the flames of the burner nozzles 54 and to prevent them from becoming too rapidly cooled. The affect of these plates is to promote combustion and to cause the burner 2 to operate at all times with a blue flame. It has been observed that when the side plates 56 are not used, by increasing the supply of gas to the nozzles 54, the small blue flame that these burners provide when fed a limited supply of gas, changes to a yellow flame, which upon further increase in the gas flow becomes a blue flame when the gas stream impinges upon the spreader plates 57 The reason the burner operates in this manner is because for very small gas flows sufiicient air is drawn and mixed with the as by way of the openings 55 to provide a lue flame. On increasing the supply of gas,

a reater amount of gas flows through the y tube 54 and the small openings 55 are notlarge enough to admit a suflicient supply of air to cause the gas to burn with a blue flame.

The flame by reason of its conical shape and small exposed area does not come in contact with enough air to burn with a blue flame. Upon the further increase of the gas flow the flame impinges upon the spreader plates 57 and is spread out in a flatcylindrical sheet which exposes a great area of the flame to the air and assures the complete combustion of the gas.

At such times when the burner flame is a yellow flame as would occur at certain times in its operation when the shields 56 are not used this yellow flame would produce a certain amount of soot or carbon that would be heater parts cutting downdeposited on the the thermal conductivity and lowering the efiiciency of the heater. the shields 56 my improved gas burner operates at all capacities with a blue flame providing a very etficient gas burner which does not produce soot or carbon and which completely consumes the gaseous fuel used.

In starting the burner the valve 40 to the by-pass 39 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 43 which moves to the left as viewed-in Fig. 1, urging the valve head 36 to its open position;

By this construction the thermostatic strip 4-3 when in a heated condition acts as a spring tending to urge the valve head to its open position. When in a cooled state the thermostatic strip holds the valve head 36 against its seat closing off the main gas supply to the burner and preventing the admission of this gas supply to the burner until the pilot the provision of flames supplied by the conduit 39 have been burning some time.-

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 shutofl' of the gas supply to the main burner at such times as when it would be dangerous to admit such flow of gas to the burner, namely, upon the extinguishment of the burner flames. The thermostat tube 5, which is immersed in the fluid that is being heated and is responsive in its operation to the temperature of this fluid, is operatively connected to the valve by means ofthe rod 6, the compounding lever 8 and the plunger 21;

It is to be noted that there is no positive connection between the tank thermostat and the valve head which controls the fiow of gas to the main burner. The thermostat is arranged to positively close the valve defined by the valve head 36 and the valve seat 35 when the temperature of the liquid that controls' its operation reaches a predetermined point. This action is accomplished by the differential expansion of the rod 6 and the tube 5 which in a heated condition causes the end of the rod 6 which is in contact with the compounding lever 8 to move to the right as viewed in Fig. 1.

The coil spring 23 which acts on the lower end of the compounding lever causes this lever to follow the movement of the rod 6 of the thermostat and in this manner the plunger 21 is caused to make contact with the valve head 36 moving it against its seat 35. When the temperature ofv the water within the tank has fallen below the predetermined limit for which the thermostat is set, contraction of the rod and tube moves the end of the thermostat rod 6 which-is in contact with the compounding lever 15 to the left as viewed in Fig.1 causing the lower end of the compounding'lever 8 to move in the same direction and carrying with it the plunger 21. The plunger 21 is not connected to the valve head36 but is in contact therewith and upon moving in the direction as just stated, allows the valve head to be shifted to its open position by the thermostatic metal 43.

If the thermostatic metal is in a heated condition, which condition would only occur when the burner 2 is in operation, the valve would be opened and an increased supply of gas admitted thereto. Should the burner have been extinguished for any reason, prior to the above named operation of the thermostat, the thermostatic metal would be in a cold condition and would not open the valve but would maintain the valve head 36 in contact with-its seat 35.

From the foregoing it is apparent that the main gas supply to my improved burner is at all times responsive to the heat of the the valve and in the absence of such heat-0r 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 thermostat turned on the gas after the burner flame had been extinguished.

for the opening of Another advantage of the construction il- .lustrated is that all the operating elements of the sysem 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.

y improved burner and safety'control could be used in connection with other gas burning appliances where the operation of the burner isautomaticallycontrolled by the temperature of the medium which the burner is adapted to heat.

' urthermore, it is to be understood that the particular forms of apparatus shown and described, and the particular procedure set fort are presented for pur oses of explanation and illustration and that various modifications of said apparatus and procedure can be made without departing from I my invention as defined in the appended claims.

I claim 1. A thermostat for gas fired liquid heaters comprising, .an expansible tube adapted to immersed in the liquid of said heater, a f rod carried in said tube and having a relatively low coefficient of expansion, an ad- 40 justable fulcrum bearin a fulcrum lever Y engaging'fsaid bearing a apted to be operatrvely connected to said rod at a point ad- Y i-jacent said 'fulcrum bearing, valve means adapted tobe controlled by the movement of thelower' end of said compounding lever and normall following the movement of the 1 lever t rough its" allowable {in heated conditionas compare wit ordinary room temperatures to cause said valve I omprising, a-valve body havin a valve port cooperating s"aid port 'to'control fluid flow therethrough,ai ifesilient,thermostat operatively 1 eo ted to said .valve' head to efi'ect the peningfmovement thereof, and a relatively lilgidlgradilatingthermostat adapted to co 1,; tro'l the operation of said "valvefhead and I to a thereofg 7 I travel, and a.

ft ermostatlc devlces'erving as as rm when EDMUND J. TE PAS.

A- thermostatically controlled valve i my signature.

"resilient thermOs'tat -directIy-in aci i; thestmpmti e g s