US2192858A - Fuel burner control system - Google Patents

Description

DU WAYNE J. PETERSON FUEL BURNER CONTROL SYSTEM Filed March 17, 1957 March 5, 1940.

awe/whom Patented Mar. 5, 1940 UNITED STATES FUEL BURNER CONTROL SYSTEM Du Wayne J. Peterson, Chicago, Ill., assignor to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn., a corporation of Delaware Application March 17, 1937, Serial No. 131,363

5 Claims.

The present invention relates to a fuel burner control system and more particularly to oner for heating the residence is usually located in,

the basement and when a flood does occur the fuel burner is liable to be extinguished. Where some automatic fuel feeding means is provided, the operation of the fuel feeding means is apt to continue after the extinguishment of the burner. This is a serious matter with any type of fuel. Even in the case of a solid fuel such as coal, it is not desirable to have a continuous feeding of the fuel after the fire has been extinguished. The extinguishment of the burner presents particular difficulties, however, when the fuel is a fluid fuel such as gas. In this'case,rthe burner is extinguished but the gas continuesito bubble through the Water filling the basement with dangerous fumes. While automatic fuel feeding apparatus is quite commonly provided with some means for stopping the feeding of the fuel upon extinguishment of the burner, such means oftenbecomes inoperative when immersed in water. Thus, in the case of a safety pilot switch which is opened upon the extinguishment of combustion, the subjecting of the switch to water will short the contacts and cause the circuit controlled thereby to be closed even though the pilot is extinguished.

An object of the present invention is to provide a control system for a fuel burner located where flooded conditions may occur, having a float actuated means for causing the supply of fuel to the burner to be interrupted upon the presence of liquid at a level sufficiently-high to affect oper tion of the burner. I

A urther object of the present invention is to provide a control system for a fuel burner employing electrically operated fuel feeding controlling means operative only whenenergized to cause fuel to be fed to the burner, which has a normally closed switch in the energized circuit of the fuel feed controlling means and a float for moving the switch to open position upon liquid rising sufficiently high to affect operation of the burner.

A further object of the present invention is to provide a control system of the type previously discussed in which the switch is a snap action switch and in which manual resetting means is is located within the furnace.

provided for moving the switch back to circuit closed position after having been moved to circuit open position by the float.

Other objects of the invention will be apparent from a consideration of the accompanying 5 specification, claims and drawing.

For a more complete understanding of the present invention, reference is made to the accompanying drawing in which Figure l is a schematic view of my improved fuel burner control system, and in which Figure 2 is a view partly in section of a float switch employed in the burner control system of the present invention.

Referring to Figure 1 of the drawing, a convenl5 tional furnace is indicated by the reference numeral ID. This furnace may be of any well known type, being shown for purposes of illustration as a warm air furnace, having ducts ll leading to rooms which are to be heated. A gas burner I4 The gas burner is supplied with gas through a pipe l5 in which is interposed a valve I6. A pilot burner I1 is located adjacent to the main gas burner I 4 and is supplied with gas from pipe l5 at a point ahead of the valve l6.

The valve i6 is provided with an operating unit IT. This operating unit is of an electrical type and preferably of a type referred to commonly as a stalled motor type. This type of operating unit for a valve is shown in the patent to Paul F. Shivers No. 1,678,202 of July 24, 1928. In this type of device, the valve is, biased towards closed position and the motor moves the valve against this bias to open position and maintains it in open position so long as the motor is energized. Upon deenergization of the motor, the biasing means returns the valve to closed position. It is to be understood that any type of electrically operated fuel feed controlling means may be employed, however, in lieu of the assembly consisting of valve I6 and operating unit IT.

A room thermostat or other automatic control device is employed to control the energization of the valve operator l1. In the drawing, a room 5 thermostat has been shown and is indicated by the reference numeral 20. This thermostat consists of a bimetallic element 2|.to which is con-- .is so disposed that upon a decrease in temperature, contact arm 22 is moved into engagement with contact 23' and upon an increase in temperature, the opposite action takes place. The efiect of the magnet 24 is to cause contact arm 22 to move into engagement with contact 23 at a different temperature than that at which it moves away from contact 23.

Transformer 30 is employed for supplying energy for operation of the system. The transformer 30 comprises a line voltage primary 3| and a low voltage secondary 32. The line voltage primary 3| is connected to two line wires 33 and 34.

The fioat switch which, as has been previously indicated, operates to insure the closing of the valve upon flood conditions is indicated generally by the reference numeral 40. This float switch is shown in detail in Figure 2. The float switch is contained in a housing having an enlarged portion 4| constituting its base and acting as a float chamber, an elongated tubular portion 42 extending upwardly from the enlarged portion, and a switch casing 43 located on top of the tubular portion 42. Located within the switch casing 43 is a mercury switch generally indicated by the reference numeral 45. The mercury switch is of the conventional type having two electrodes at one end and a mercury globule, which, upon tilting of the switch, moves into and out of bridging engagement with these electrodes. The mercury switch is mounted upon a support 46 to which is attached a clip 41 pivoted at 48 to the casing 43. The pivot point 48 is located in line with the center of gravity of the switch, exclusive of the mercury, so that the mercury acts to hold the switch in either extreme position to which it is moved. The two electrodes of the mercury switch 46 are connected to two terminals 7 49 and 50 which are adapted to have conductors secured thereto. The tubular portion 42 is sufficiently lohg that switch 45 will be above the highest level to which the flood water will rise.

A rod 52 extends through the tubular portion 42 of the housing of float switch 40, being guided for longitudinal movement therethrough. This3 rod extends clear to the bottom of the housing and is adapted to rest upon. the floor or other similar supporting surface. The rod extends at its upper end into engagement with the switch support 46. The rod 52 is so aligned that it engages with the switch support at a point to the right of the pivot point 48 so that upon upward movement thereof the switch 45 is tilted in a counterclockwise direction. Supported'on 1 liquid to the interior of the float chamber.

If the float 54 becomes surrounded with water, it raises and moves rod 52 upwardly to cause counter-clockwise movement of switch 45. When switch 45 passes its horizontal position, the effect of the mercury globule is to cause it to rapidly rotate in counter-clockwise direction. The movement of the mercury globule away from the electrodes breaks the circuit controlled by the switch. In order to provide means for limiting the 'movement of the switch 45 in the direction of its open circuit ,position and to provide for readily moving the switch back to its circuit closed position, a rod 60 extends through the casing 43. This rod 60 is provided at its outer end with a push-button 6|. A spring 62 is interposed between the push-button 6| and the switch casing 43 and serves to bias rod 60 outwardly. A collar 63 is secured to rod 60 and serves to limit the outward movement of the rod. The rod 66 is so positioned that upon counter-clockwise movement of switch support 46, the right end of the support will engage the rod 60. When it is desired to reclose the switch 45, all that is necessary to do is to push push-button 6| and the switch 45 is rotated in a clockwise direction to again assume the closed position shown in the drawing.

The mounting of the switch 45 so that the same remains in either circuit open or circuit closed position, depending upon which position it is moved to, is highly desirable inasmuch as it would not be advantageous to have the switch moved back to closed position until it was assured that conditions were such that operation of the burner was again desirable. With the arrangement shown and described, it is assured that switch 45 after having once been opened will not be reclosed until the manual operation of pushing push-button 6| has been performed.

Referring again to Figure 1, it will be noted that one terminal of the secondary 32 is connected to the switch terminal 49 through conductor 65. Switch terminal 50 is connected by conductor 66 to one terminal of the valve operator H. A conductor 61 connects the other terminal of the valve operator to the bimetallic element 2|. A contact- 23 of the thermostat 20 is connected by conductor 68 to the other terminal of secondary 32.

Operation Since the switch 45 .is normally closed, terenergization of the valve operator by the estab lishment of the above traced circuit causes valve IE to be moved to open position against the action of its biasing means, in the manner previously explained. I

Let it be assumed that water or other liquid enters the room in which the furnace I0 is located. This room, of course, would normally be the basement. The water will enter the inside of the base portion 4| constituting the float switch housing through the openings 51 and will cause the float 54 to rise by reason of the buoyant action of "the liquid. The rising of float 54 will cause upward movement of rod 52 so as to tilt the mercury switch 45 sufliciently to cause it to snap over center. Since switch 45 is in series with the valve operator, the energizing circuit thereto, if established, will be interrupted causing the valve to move to closed position. If the energizing circuit is not established, it will be assured-that the valve will not be opened upon .a call for heat.

Due to the fact that the switch flops or snaps over center, it is assured that the valve will remain closed until such time as an operator manually moves the switch 45 to closed position by pushing push-button 6|. In this way, it is assured. that if the water has in any way damaged which is positive and direct.

the heating equipment, the valve will not be opened as soon as the water has subsided.

It will be seen that the present invention provides a fuel burner control system in which it is assured that the supplying of fuel to the burner will be interrupted upon liquid rising to a level which would affect operation of the burner. This moreover is done through a float actuated device Moreover, it is seen that the switch forming a portion of my apparatus is located at a height sufficiently high that the flood waters will not reach the same. In this manner, it is assured that regardless of the extent to which the basement is flooded, the switch will always function to open the circuit to the operator of the fuel feed controlling means.

While I have shown a specific embodiment of my invention, it is to be understood that this is for purposes of illustration only and that my invention is to be limited only by the scope of the appended claims.

I claim as my invention:

1. In a gas control system, in combination, a device for controlling a flow of gas, said device being located in an enclosure susceptible to becoming flooded and thereby indicating flooded conditions in the vicinity of the enclosure, said gas being of a type employed in systems of such a nature that exposure of the systems to flooded conditions may create a dangerous hazard, a

flood protection safety device comprising means responsive to rising flooding liquid operable to cause interruption of the flow of gas while the flooding liquid is at or above a predetermined level in said enclosure.

2. In a gas, control system, in combination, a device for controlling a flow of gas, said device being located in an enclosure susceptible to becoming flooded and thereby indicating flooded conditions in the vicinity of the enclosure, said gas being of a type employed in systems of such a nature that exposure of the systems to flooded conditions may create a dangerous hazard, and a flood protection safety system comprising an electric valve and means responsive to rising flooding liquid operable to cause interruption of the flow of gas while the flooding liquid is at or above a predetermined level in said enclosure,

said last means including a circuit controlling said valve and circuit interrupting means located at a level above the normal rise of flooding liquid.

3. In' a heating system for a building, in combination, means forming a combustion chamber in the basement of the building, means for burning gaseous fuel in said combustion chamber, said basement being susceptible to becoming flooded, means for normally controlling a supply of gaseous fuel to the fuel burning means, and means responsive to the presence of.flooding liquid in said basement for interrupting supply of fuel to said fuel burning means while theliquid is at or above a predetermined level in said basement.

4. In a control system for a gaseous fuel in combination a burner located within an enclosure susceptible to becoming flooded, means for normally controlling the supply of fuel to the burner comprising means for forming an electric circuit, said fuel supply means admitting fuel to said burner when said circuit is completed, means responsive to-the presence of flooding liquid in said enclosure for interrupting said circuit to prevent admission of fuel to said burner while the liquid is at or above a given level, said last means being arranged to avoid having flooding liquid act thereon to close said circuit irrespective of the effect of flooding liquid on other portions of the circuit, and the presence of said flooding liquid characterizing a condition independent of burner operations.

5. In a control system for a gaseous fuel in combination a burner located within an enclosure susceptible to becoming flooded, means for normally controlling the supply of fuel to the burner comprising means for forming an electric circuit, said fuel supply means admitting fuel to said burner when said circuit is completed, and means responsive to the presence of flooding liquid characterizing a condition in said enclosure independent of burner operations for interrupting said circuit to prevent admission. of fuel to said burner while the liquid is at or above a given ,level, said last means comprising a device movable by the flooding liquid and a switch situated so as to be above the level of the rise of flooding liquid.

DU WAYNE J. PETERSON.

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