US2362247A - Burner control - Google Patents

Description

NOV. 7, 1944. c N 2,362,247

BURNER CONTROL Filed April 25. 1942 IN VENTOR. [04 /us Co/vvsese ATTORNEYS i is a bracket fixed with respect to pilot 24.

Patented Nov. 7, 1944 BURNER CONTROL Julius Converse, East Cleveland, Ohio, assignor -to The Bryant Heater Company, Cleveland, I

Ohio, a corporation of Ohio Application'April 25, 1942, Serial No. 440,519

4 Claims.

This invention relates to improvements in burner controls, more especially controls embodying pilots having electric igniters.

One of the objects of the invention is the provision of simple means responsive to gas pressure embodying a flexible diaphragm l2 adapted to engage an annular seat l3 for closing connection between the pipe I and a second pipe M which extends to the burner to be controlled, not shown herein. Above the diaphragm I2 there is 'a control chamber l5 which is in free communication through a tube I6 with the intermediate port of a three-way valve ii, that is to say the tube l6 communicates with the valve chamber between two seats l8 and [9. A ball is adapted to engage one or the other of these seats, being biased toward the seat l8 by a coil spring 2|.

Communicating with the valve I! on the outer side of seat l9, there is a tubularconductor 22 which extends to the supply pipe l0. When the ball 20 is in the position illustrated, gas flows from the pipe l0 through tube 22 to valve I1, and

thence through tube [6 to control chamber l5 of the diaphragm valve, thereby forcing the diaphragm [2 down against the seat l3 ofthe valve to close the latter.

' A' tube 23, connected at its lower end with tube 22, leads to a pilot 24 arranged of course in proximity to the burner to be controlled. At a suitable point in the tube 23 amixer 8 is provided, such that the richness of the mixture is dependentupon the rate of flow of the gas. 25 To this bracket there is anchored one leg of a horseshoe thermal member 26, the inner radius of which is adapted to be heated by flames from the pilot in order to cause expansion of the member 26, thereby swinging the free leg of the horseshoe away from its anchored-leg. The bracket 25 and the valve I! are joined by a tubular housing or guide 21 in which is mounted a rod 28 that extends down thr'ough'the body of valve ll (Cl. 158-117.1) i

into engagement with ball 20. When the horseshoe expands, the rod 28 is moved longitudinally forcing the ball 20 off its seat I8 against the action of spring 2| and finally causing the ball to engage seat l9. When this occurs, the pressure in control chamber I5 is exhausted through tube l6, past the seat I8 and out through a bleed conductor preferably to a position where the gas bled from the chamber l5 will be ignited by the *pilot 24 or the main burner.

Tube 23 is under control of a valve 30, shown herein as a delayed action valve operated electrically. The valve body contains a seat in communication with the tube 23, which seat. is en-.

gaged by a ball 3! when thevalve is closed. To open the valve I provide a bi-metal blade 32 anchored at one end in thevalve housing, the opposite end being adapted to engage the ball and tilt it up off its seat when the bi-metal blade is warped by heat. A portion'of the blade is covered by an insulation sleeve over which is wound a heating coil 33 electrically connected with the blade at 34 and at its opposite end with a bind ing post 9. The anchored. end of the blade is electrically connected with a second binding post 35 and to these two binding posts are connected electric conductors 36 and 31 leading to the secondary coil of a transformer 38 of the reactance type, one of these conductors including a room thermostat 39 or other suitable switch means. It will be apparent that when the circuit is completed through conductors 36 and '31, coil 33 will be energized and will heat bi-metal 32, the outer end of which will be deflected upwardly to open the valve. Upon the opening of the switch controlled by thermostat 39, coil 33 will cool and the blade 32 will gradually return to its original condition, thus providing delayd action permitting the ball 3| to again engage its seat.

In accordance with the present invention I provide electric ignition for the pilot 24. This may comprise an igniter coil 40 positioned in igniting relation to the pilot. The coil 40 is included in a circuit comprising the secondary coil of the transformer 38 and conductors 4| and 42. In this circuit 1 include circuit controlling switch means which functions automatically to bring about the energization of the igniter coil when conditions in the system are correct, that is to say when gas is being supplied to the pilot and the diaphragm valve is closed, or when at least one of these conditions is satisfied. I have illustrated herein one such convenient switch means which embodies a small housing 43 built onto the upper part of the diaphragm valve, together with a cover 44 into which is connected a tube 45 that communicates with tube 23. Interposed between the housing 43 and the diaphragm valve housing there is a small diaphragm 46 and a similar diaphragm 41 separates housing 43 from cover 44. Housing 43 includes an intermediate wall 48 which is open at the middle. On the opposite surfaces of the wall 48 there are ring conductors t9 and 59 from which extend terminals and 5?. for connection with conductors 4| and 42. These rings are provided with buttons that are adapted to be engaged by metal plates 53 and 54 attached respectively to the diaphragms 46 and 41. A compression spring 55 engages both of these plates and extends through the central opening in the wall 48.

When chamber I5 is filled with gas under line pressure, diaphragm 46 is raised into engagement with the buttons on ring 59. Similarly, when gas under line pressure is present in tubes 23 and 45, diaphragm 4'! is depressed and plate 54 engages the buttons on ring 49. When both of these conditions obtain, current may pass from conductor 4i through terminal 52, ring 59, plate 53, spring 55, plate 54, ring 49 and terminal 5i to conductor 42.

Operation.When the burner is off, the parts occupy the positions illustrated in the drawing, there being pressure in the control chamber l5 of the diaphragm valve and the pilot being out. Now when the thermostat 39 calls for heat, coil 33 is energized, and after a short interval the bi-metal 32 deflects sufiiciently to unseat ball 3!. Gas under line pressure then flows to the pilot 24 through tube 23 and to the upper side of small diaphragm 41 through the tube 45. Diaphragm 47 i thus depressed, and since the diaphragm 46 is already raised, owing to pressure in chamber l5, the circuit through igniter coil 43 is completed. That coil then quickly builds up to the temperature necessary for effecting combustion of the gas discharged from pilot 24. In doing so it draws so much current that coil 33 cools off. In case the pilot should not be ignited by the first energization of coil 49 the bi-metal will then gradually return to its original position permitting the ball 31 to seat itself, thereby cutting oil? the flow of gas to the pilot and exhausting the pressure from tube 45 which then permits spring 55 to raise diaphragm 4?, breaking the circuit through the igniter coil. Current is then again available in sufficient amount to fully energize coil 33 which results in again opening the tubes 23 and 45 to line pressure and again energizing the igniter coil, this procedure repeating itself until the ignition of the pilot is efifected.

When the pilot burns, it applies flame to the inner curved Wall of the horseshoe, causing the latter to expand and swing its free leg 23 against the end of rod 28 which moves longitudinally to push valve ball 29 off its upper seat It. Gas then flows from tube 22 through valve I! and out through bleed 29. This movement of rod 23 continues until ball 29 engages seat l9, when the line pressure is out 0i? and the'gas in chamber 15 exhausts through tube It, valve I1 and bleed 29. Diaphragm valve 12 then rises from its seat 13, permitting gas to flow to the main burner through pipe l4. At the same time small diaphragm 46 descends, which opens the circuit through igniter coil 49. The ball 3! is still off its seat somewhat because of the delayed action of valve 39, it being observed that the coil 33 is in a closed compartment and hence does not cool rapidly. Now, with the coil 40 deenergized, coil 33 again heats up and remains in that condition so long as the thermostat 39 calls for heat. The pilot 24 therefore burns throughout the period of operation of the main burner. When the thermostat is satisfied and coil 33 is deenergized, valve 30 closes, terminating the operation of the pilot. The horseshoe then contracts and spring 2| moves ball 20 and rod 28 upwardly again, admitting pressure to control chamber l5 and causing ball 29 to engage seat [8. This will close the main valve and the lower half of the switch means for the igniter circuit, but the upper part of the switch will have been previously opened by the exhausting of pressure through tubes 45 and 23. The parts will then all be in the condition illustrated in the drawing and ready for the next cycle of operations.

When the igniter coil is energized its tempera-- ture builds up to a predetermined maximum. At the same time the valve 30 is gradually closing so that the flow of gas through "the tube 23 is decreased, resulting in variation of the gas-air mixture reaching the pilot. Also, when the igniter circuit is broken the temperature of the coil 49 decreases while the flow of gas through the tube 23 is increasing. A definite and critical mixture of natural gas and air and a definite and critical coil temperature are both necessary for ignition. From a practical standpoint it is impossible to establish the best combination of conditions by mechanical means to meet the many difierent field conditions, that is variations in gas constituents, which are encountered in difierent localities. By means of the present invention however varying combinations are created automatically during the lighting cycle, and the correct combination is bound to occur at some stage of the cycle so that ignition is relatively certain in all cases.

Having thus described my invention, what I claim is:

In gas apparatus, a main diaphragm valve, a pressure chamber therefor responsive to line pressure for closing said valve, 2. pilot, a gas supply therefor, a second pressure chamber in communication with said pilot, an electric igniter for the pilot, an electric circuit for said igniter, and switch means in said circuit coincidentally responsive to pressure in both of said chambers for closing said circuit.

2. In gas apparatus, a diaphragm valve for controlling the flow of gas to a main burner. a control chamber of which the diaphragm for said valve forms one wall, a pilot, a gas supply therefor, an electric igniter for the pilot, and an igniter circuit comprising switch means having two elements both of which must be actuated in order to complete the circuit, one of said elements being responsive to pressure in the control chamber of the diaphragm valve and the other being responsive to pressure within the gas supply to the pilot burner.

3. In gas apparatus, a gas supply, a diaphragm valve for controlling the flow of gas from said supply to a main burner, a control chamber of which the diaphragm for said valve forms one wall, a pilot, a gas conductor extending from said supply to said pilot, a pilot-operated valve functioning when the pilot is cold to connect the gas supply to the control chamber of said diaphragm valveand when the pilot is hot to exhaust pressure from said control chamber, an electric igniter for said pilot, and means dependent upon simultaneous pressure in said control chamber and said gas conductor for energizing said igniter.

4. In gas apparatus, a gas supply, a pilot, a gas conductor extending from said supply to said pilot, said pilot having a primary air intake, an igniter coil for the pilot, a circuit for said coil, an electrically operated delayed action valve in said conductor, and a common source of current

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