US3282325A - Jackson etal burner control apparatus - Google Patents

Description

Nov. 1, 1966 w. F. JACKSON ETAL 3,232,325

BURNER CONTROL APPARATUS Filed June 5, 1964 ATTORNEYK United States Patent 3,282,325 BURNER CQNTlROL APPARATUS Wilbur F. Jackson, Rolling Hills, and John W. Wright, Long Beach, Calif., assiguors to Robertsha-w Controls Company, Richmond, Va., a corporation of Delaware Filed June 3, 1964, Ser. No. 372,22tl 3 Claims. (Cl. 158-129) This invention relates to fuel burner control apparatus and in particular to a combined pilot flow valve and thermal switch arrangement performing an automatic pilot function in fuel burning systems such as gas operated heating and/ or cooling systems.

In certain installations, the flow of gas to the fuel burning apparatus is controlled by a gas control valve which monitors a pilot flow of gas to a pilot burner and a main flow of gas is effected by various types of main valves, such as a solenoid valve, a heat motor valve, or a diaphragm valve. operating on the bleed principle; each of these types of main valves include an electric actuator in series with a temperature responsive device, such as a room thermostat, to cause main valve actuation automatically in accordance with deviations from a preset temperature in the space being temperature controlled. In order to obtain 100% shut off of the gas flow with such main valve, it has been necessary to provide the gas control valve with a safety pilot valve to shut off gas how to both main and pilot burners upon extinguishment of the pilot burner flame. Such an arrangement required an expensive and complicated control device as by incorporating the safety pilot valve and a manually shut off cock with the main valve and utilizing an automatic pilot operator to shut off the gas flow.

It is therefore, an object of the present invention to eliminate the need for automatic pilot operators in the control valve of fuel burner systems having main'and pilot flow burners.

The present invention has another object in that the electric actuator of a main control valve is electrically connected to the switch of a pilot valve and switch combination.

Another object of this invention is to construct a combined pilot valve and pilot switch in a simple and economical manner.

It is another object of this invention to provide a pilot valve and switch combination with a bypass flow of fuel during a resetting operation.

The present invention has a further object in that a fuel bypass fiow to a pilot burner is established without actuation of the pilot valve and switch combination.

A further object of this invention is to combine a pilot burner, pilot flow valve means and thermal switch means in a unitary housing.

In a preferred embodiment of the present invention, control apparatus for a fuel burning system having main and pilot burners includes a main valve means with an electric actuator for controlling a main flow of fuel to the main burner, pilot valve means for controlling a flow of uel to the :pilot lburne-r which is disposed adjacent flame responsive means, switch means electrically connected to the electric actuator, and lever means operatively connected between the pilot valve means and the switch for combined operation thereof, the lever means being movable in response to movement of said flame responsive means to effect a combined operation of the pilot valve means and the main valve means.

Additional features and advantages of the present invention will become apparent from the following description of the preferred embodiment, taken in connection with the accompanying drawing. The single figure of the drawing is a schematic arrangement with parts in section illustrating a fuel burning system incorporating the present invention.

The control apparatus shown in the drawing includes a gas control device housing or casing, indicated generally at 10, having an inlet 12 connected to a source of gaseous fuel (not shown) and an outlet 14 connected to the main burner apparatus 16 of a fuel burning system, such as gas operated heating and/or cooling systems. The inlet and outlets are separated by a main valve which may be of any suitable type but for the purposes of this description, is shown as a diaphragm valve 18 having a main valve chamber 20 communicating with the inlet 12 and having an operating pressure chamber 22 on the undersides of diaphragm valve 18. A bleed flow passage 24 on the inlet side of valve 18 has communication with two branch passages, one such passage 26 leading to the operating pressure chamber 22 and the other passage 28 =leading to the outlet side of valve 18. A fiow restrictor 29 is disposed in the passage 24 upstream of the branch passage 26 to provide the bleed line pressure drop required to assure operation of the diaphragm valve 18. An electrically actuated ball valve 30 operatively disposed in the bleed flow passage 28 controls the pressure in the operating pressure chamber 22 to effect operation of the main d-iaphgram valve 18 which is biased toward its closed position by a helical coil spring 32. Whenever the ball valve 30 is closed, the bleed fiow through passage 28 is cut off and the bleed flow from passage 24 feeds into the operating pressure chamber 22 whereby the underside of the diaphragm valve 18 is subject to inlet pressure and is closed by the coil spring 32.

The ball valve 36 is actuated as by a bimetal heat motor actuator or by electric means in the form of an electromagnet having a U-s-haped core 34, a coil 36 and a keeper lever 38 intermediately fulcrummed on one leg of the core 34. The free end of lever 38 carries the operating stem 40 of the ball valve 30 and a tension spring 42 normally biases the opposite end away from the core 34 and the stem 40 and the valve 30 toward a valve closed position.

Adjacent inlet 12, the casing 10 is provided with a pilot flow passage 44 which is branched into two pilot flow passages 46 and 48. The pilot flow pass-age 46 defines a regular flow for pilot burner fuel while the passage 48 defines a bypass or reset flow for pilot burner fuel. Intermediate the passage 48, a normally closed valve 50 cuts oil. the reset flow. A push stem 52 on valve 50 protrudes through the wall of casing 10 and carries a push button 54 on its end; a coil spring 56 encircles the protruding portion of stem 52 and is mounted in compression between the wall of casing 10 and the underside of push button 54.

As is illustrated in the drawing, a control device housing 55 is secured adjacent the main burner 16 in such position that its burner is utilized to ignite the main burner 16. The housing 55 includes a pair of pilot flow inlet passages 56 and 58, with the passage 56 externally connected to the outlet of the pilot flow passage 46 and with the passage 58 externally connected to the outlet of the reset pilot flow passage 48. The pilot flow passage 58 communicates with an internal passage 60 which feeds a pilot burner 62; the pilot burner 62 includes the structure of a nozzle portion 64 adjacent an opening in the wall of the housing 55 which is covered by a deflector 66 having a lower cylindrical member and an upper flat plate axially inclined thereto.

A flow of pilot burner fuel from passage 56 also feeds into the internal passage 60 but the flow thereof is controlled by valve means 68 in the form of a movable valve member. The valve member 68 is secured to one end of an operating lever 70 for actuation thereby. Intermediate its ends, the lever 70 is deformed to define a semispherical detent 72 on its upper surface. A coil spring 74 mounted in compression between a bottom wall recess 76 in the housing 55 and the undersurface of the detent 72 which is thus biased into engagement with flame responsive means.

The flame responsive means is of the rod and tube type in which a tube element 7 8 has an outer portion disposed adjacent the pilot burner deflector 66 to sense the existence of a flame therefrom. The tube has an inner portion extending through a suitable opening in the wall of the housing 55 and secured thereto as by a press fit or by a lock nut 80. The tube 7 8 defines a cylindrical shell for an actuating rod which has an operating portion 82 disposed in the housing 55 in engagement with the detent 72 on the lever 70. The rod and tube of the flame responsive means are made of different material to effect thermal expansion and contraction as is well known in the art; of course other types of flame responsive means may be utilized.

The undersurface of the other end of the lever 70 engages a switch actuator 84 which extends through a bore in the bottom wall of housing 55; an O-ring seal encircling the inner part of the actuator 84 provides a seal 85 for the housing bore. As is illustrated in the drawing, the actuator 84 extends into an external recess 86 which is closed by a flush mounted switch block 88. A first contact 90 is fixed on the block 88 and a second contact 92 is mounted on a current carrying spring blade 94 normally biases the movable contact 92 away from the fixed contact 90 and into engagement with the end of electric switch actuator 84.

The various electrical components and the electrical circuitry therefor will be described in appropriate places in the following description of the sequence of operation of the present invention. The relative positions of the various valves and switches are shown in the drawing in their shut conditions, i.e., the main burner 16 and the pilot burner 62 are not burning, thus, main valve 18 is closed, bleed flow valve 30 is closed, reset pilot flow valve 50 is closed, regular pilot flow valve 68 is closed and electric switch 90-92 is opened.

In order to place the device in operation, the push button 54 is manually depressed to open the valve 50 and a flow of pilot burner fuel may be traced from inlet 12, through the pilot flow passage 44, the branch passage 48, the pilot flow passage 58 and the internal passage 60 to the pilot burner 62 where it is ignited as by a match. The pilot burner flame is thus deflected toward the adjacent flame responsive means 78 which causes expansion thereof so that the inner operator 82 depresses the lever 70 against the bias of the coil spring 74. With the lever 70 in its depressed position, the pilot flow valve 68 is opened; the push button 54 may be released to closed valve 50 because the regular flow of pilot burner fuel is established from branch 46, through the inlet passage 56 to the internal passage 60.

The depressed position of the lever 70 also causes the closure of electric switch contacts 90-92 so that the entire apparatus is now in condition to cycle thermostatically. Assuming now that the space being temperature controlled is calling for heat as determined by a thermostatic device, such as a room thermostat RT, the contacts of the room thermostat RT are closed to complete an electrical circuit which may be traced as follows: the secondary coil of a transformer T has a stepped down voltage (e.g. 24 volts) in response to energization of the transformer primary coil from lines L1 and L2 of the usual voltage (e.g. 110 volts); from the secondary conductor 100, through the closed contacts of the room thermostat RT, the conductor 102, the fixed contact 90, the movable contact 92 and blade 94, the conductor 104, the terminal post 106 on the control device casing 10, the energizing coil 36, the terminal post 108 and the conductor 110 back to the secondary of the transformer T.

- Energization of the coil 36 attracts the keeper 38 to the electromagnet core 34 whereby the ball valve 30 is opened against the bias of the coil spring 42. Upon opening the ball valve 30, the bleed flow passages 24 and 26 communicate with the passage 28 whereby the operating pressure chamber 22 is bled to the outlet 14. The restrictor 29 assures a pressure drop in the chamber 22 and such decrease in pressure permits the main diaphragm valve 18 to open because of the inlet pressure of the fuel in the diaphragm chamber 20. With the main valve 18 opened, the, main flow of fuel proceeds to the main burner 16 where it is ignited by the flame from the pilot burner 62.

As soon as the demand for heat is satisfied, the contacts of the room thermostat RT are opened and the elec trical circuit for the electric actuator coil 36 is broken. Thus the ball valve 30 is closed and the underside of the main diaphragm valve is subject to inlet pressure with the bleed flow from bleed passage 24 proceeding through the bleed passage 26 to the operating pressure chamber 22. With the main diaphragm valve 18 being subject to equal pressures on opposite sides thereof, the coil spring 32 biases the valve to a closed position and shut off the flow of fuel to the main burner. It is now apparent that the electric actuator for the ball valve 30 is thermostatically cycled by the room thermostat RT to eifect open and closing of the main valve 18.

If at any time the flame from the pilot burner 62 should be extinguished, the subsequent cooling and contraction of the flame responsive means causes the lever 70 to be biased to its upper position; thus the pilot flow valve 68 is closed and the electric switch -92 is opened. Even though the contacts of the room thermostat RT are closed at this time, the opening of the electric switch 90-92 causes deenergization of the electric actuator coil 36 so that the ball valve 30 is closed resulting in closure of the main valve 18 as described above.

With the above arrangement, the apparatus may be reignited only by depressing the push button 54, which does not require any connection or interlock for manually operating the lever 70. shut off of all fuel flow is provided upon extinguishment of the flame from the pilot burner; in addition safe lighting is effected during a resetting operation because the electric switch 9092 will not close until after the flame has been restored at the pilot burner.

Inasmuch as the preferred embodiment of the present invention is subject to various modifications and numerous changes in detail, it is intended that all matter contained in the foregoing description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. Apparatus for controlling a flow of fuel in a fuel burning system having main and pilot burners, the combination comprising a main control device casing having an inlet adapted to be connected to a fuel source and an outlet adapted to be connected to the main burner, main valving means in said casing having electric actuator means for controlling a fuel flow therethrough, conduit means for a flow of pilot burner fuel bypassing said main valving means, said conduit means having a first branch defining a regular pilot flow and a second branch defining a reset pilot flow, a pilot control device housing disposed adjacent the main burner and having a pair of inlet passages and an outlet passage, one of said inlet passages communicating with said first branch and the other of said inlet passages communicating with said second branch, means mounting the pilot burner on said housing in communication with said outlet passage, valve means in said housing movable between a first position wherein the said one inlet passage is in communication with said outlet passage and a second position wherein the said one inlet passage is closed off from communication with said outlet passage, flame responsive means having a portion disposed adjacent the pilot burner and a movable portion disposed in said housing, lever means in said housing having an intermediate portion operatively connected to said movable portion, one end of said lever means being operatively connected to said valve means, switch means in said housing operatively connected to the other end of said lever means, said lever means being operative in one direction to close said switch means and to move said valve means to its first postion and in another direction to open said switch means and to move said valve means to its second position, and electric circuit means electrically connecting said switch means to said electric actuator means for actuating said main valving means and said valve means in response to movement of said flame responsive means.

2. The combination as recited in claim 1 wherein normally closed valve means is disposed in said second branch and includes operating means for movement to an open position during a resetting operation.

3. The combination as recited in claim 1 wherein said References Cited by the Examiner UNITED STATES PATENTS 1,031,913 7/1912 Casse 236-80 1,866,541 7/1932 Branche et al. 158-127 2,263,767 11/1941 Fox 158129 X 2,512,173 6/1950 Ray 158-129 2,516,504 7/1950 Cerny et al. 158127 X 2,652,110 9/1953 Main 158-129 X 3,107,856 10/1963 Holzboog et al. 158127 X FREDERICK KETTERER, Primary Examiner.

Claims (1)

1. APPARATUS FOR CONTROLLING A FLOW OF FUEL IN A FUEL BURNING SYSTEM HAVING A MAIN AND PILOT BURNERS, THE COMBINATION COMPRISING A MAIN CONTROL DEVICE CASING HAVING AN INLET ADAPTED TO BE CONNECTED TO A FUEL SOURCE AND AN OUTLET ADAPTED TO BE CONNECTED TO THE MAIN BURNER, MAIN VALVING MEANS IN SAID CASING HAVING ELECTRIC, ACTUATOR MEANS FOR CONTROLLING A FUEL FLOW THERETHTOUGH, CONDUIT MEANS FOR A FLOW OF PILOT BURNER FUEL BYPASSING SAID MAIN VALVING MEANS, SAID CONDUIT MEANS HAVING A FIRST BRANCH DEFINING A REGULAR PILOT FLOW AND A SECOND BRANCH DEFINING A RESET PILOT FLOW, A PILOT CONTROL DEVICE HOUSING DISPOSED ADJACENT THE MAIN BURNER AND HAVING A PAIR OF INLET PASSAGES AND AN OUTLET PASSAGE, ONE OF SAID INLET PASSAGES COMMUNICATING WITH SAID FIRST BRANCH AND THE OTHER OF SAID INLET PASSAGES COMMUNICATING WITH SAID SECOND BRANCH, MEANS MOUNTING THE PILOT BURNER ON SAID HOUSING IN COMMUNICATION WITH SAID OUTLET PASSAGE, VALVE MEANS IN SAID HOUSING MOVABLE BETWEEN A FIRST POSITION WHEREIN THE SAID ONE INLET PASSAGE IS IN COMMUNICATION WITH SAID OUTLET PASSAGE AND A SECOND POSITION WHEREIN THE SAID ONE INLET PASSAGE IS CLOSED OFF FROM COMMUNICATION WITH SAID OUTLET PASSAGE, FLAME RESPONSIVE MEANS HAVING A PORTION DIS-

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