US2870827A - Automatic valve and switch for fuel burners - Google Patents

Description

Jan. 27, 1959 L. T. BROCKBANK 2,87 2

AUTOMATIC VALVE AND SWITCH FOR FUEL BURNERS Filed Oct. 4, 1954 v INVENTORL Lucas 7' Brae/wank,

"M 1 H13 Attorneys.

United States Patent AUTOMATIC VALVE AND SWITCH FOR FUEL BURNERS This invention relates to improvements in electrically controlled fuel burner furnaces, having particular reference to'an automatic safety device to be connected between the burner and fuel supply, whereby simultaneously, as Well as instantaneously, to shut off the flow of fuel and to stop the operation of the burner and its blower, and the provision of such a device is a principal object of the invention.

The invention is primarily directed to fuel burners utilizing liquid fuel, such as oil burners, wherein the oil is sprayed or atomized, and the disclosure of the invention is illustrated and described along these lines. However, it should be understood that it is also within the contemplation of the invention to apply the same to other types of electrically controlled burners, or furnaces, where it is desirable, in case of'overheating and fire, similarly to shut off the fuel supply and stop the operation of the burners. a

I am well aware that safety valves and other devices for shutting off the main supply of fuel, such as oil, leading to burners of furnaces, in case of fire, heretofore have been suggested, but these do not include means for preventing the flow oratomization of residual oil between the valve and burner in the manner disclosed and claimed hereinafter. Consequently, there may be an appreciable-amount of such residual, oil which may continue to be injected into the furnace after undue overheating and fire has already started, for example, in the stack, or, as the result of an explosion, pufiing, or flareback in the furnace, whereby the fire door is blown open. Continued heaping on or adding of fuel upon the flames for even a short length of time causes the fire rapidly to spread, usually and most quickly to the ceiling timbers, as well as elsewhere, with well known disastrous results. It has long been recognized in the industry that it would be a distinct improvementif such difficulties and disadvantages could be overcome, and this now has been accomplished by means of the present invention.

Generally, it is another object of the invention also to provide such a device that is simple in construction, economic of manufacture and sale, positive in operation, will function with relative freedom from mechanical or other difficulties, and that otherwise is well suited to the purposes for which it is intended.

More specifically, it is an object of the invention to provide an automatically operable safety device for use in conjunction with an electrically controlled fuel burner furnace to be connected in the fuel line between the burner and fuel supply tank, constituting a shut-off valve normally held open when the burner is in operation, means connected to the valve normally to hold the same open, including a fusible element to be located in the vicinity of the furnace, or burner, where fire hazards are most likely to occur, an electrical shut-off switch, normally closed when the valve is open, and in circuit with the burner, and actuating means connecting the valve and switch, whereby simultaneously, as well as instanice taneously, to close the valve and open the switch upon fusion of the element.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the features of construction, combination of elements, and arrangement of parts, which will be exemplified in the construction hereinafter set forth and the scope of the application of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention reference should be had to the following detailed description taken in connection with the accompanying drawing, in which:

Fig. 1 is a schematic illustration of the invention connected between the burner of an oil type of furnace and an oil supply tank;

Fig. 2 is a side elevational view, with. parts broken away, illustrating one embodiment of the invention;

Fig. 3 is a plan view substantially of Fig. 2;

Fig. 4 is a sectional view, with parts broken away, of Fig. 2; and

Fig. 5 is a side elevational view, with parts broken away, of a further embodiment of the invention. Referring more particularly to the drawing, there is shown generally at 10 an automatically operable safety device for use in conjunction with an electrically con' trolled fuel oil burner 11 which is shown as a conventional burner including an electric motor driven blower mounted for use with a furnace 12 connected to the fuel line 13. between the burner and fuel supply tank 14. The device comprises a fuel shut-off valve 15 having a valve seat 16 adapted to receive a valve head 17 attachedtothe bottom of a valve-stem 18, slidably mounted in the top of the valve and extending therethrough. Between the head 17 and top of the valve 15, on the inside thereof, is a coil spring 19 encircling the stem which ordinarily urges secured to a spring 23 which in turn is. connected to a link, chain or cable 24. The cable at its opposite end should be secured to a brace 25 on'the furnace smokepipe 26. The purpose of anchoring the other end of the link, chain or cable on the smoke-pipe adjacent the chimney is to operate the safety mechanism, or shut the burner off, in the event an explosion or puff should occur, which would loosen or disconnect the smoke pipe from its original position. The cable passes over one or more idler rollers 27 suitably positioned with respect to the furnace. At one or more suitable places in the cable are fusible elements, such as, for example, 28 above the fire door 29 and 30 above the smoke-pipe 26. It is at the fire door or smoke-pipe lever 21 is so fulcrumed against the valve-stem 18 by means of the cable 24 that it compresses the spring 19 in order normally to maintain the valve in an open position for the free flow of oil therethrough.

Secured to the valve in any suitable manner is a bracket 31 and attached to the bracket is a mechanical shut-off switch 32, conventionally known as a switchette having a plunger 33 which, when outwardly urged from within the switch by suitable means, permits the contacts therein normally to be closed. The switchette being conventional needs no further description. Also connected to the bracket 31 is a bell crank type of arm 34 being pivoted thereto at one end as at 35. At its opposite end the arm 34 has an adjustable screw 36 cooperatively associated with the plunger 33. Pivotally connecting the arm that overheating or fire usually occurs. The

' door .29 shouldbe 34 and lever 21, as at 37 and 37, is an actuating link 38.

ower wires 40 and 41 serve the burner 11 with its usual blower. Wire 41 is connected to one contact screw 39, of switch ,32 anda wire 41; connected to the other contact screw'3 9 leads to a terminalbox-50on the. burner 11. The other power wire =40.is shown con-nected directly to theterminal box 50. It will be seen, therefore, that upon tilting of cut off .switchbylever. 2.1,moving to the valve closed position the current-through terminal box 50 -wi1lbe cut off. a p

"In operation, the valve 'i Sdsanormally opened tovpermit the "free -flow of oiltherethrough and, the switch 32 being normally closed, the burner (11 continues interniittently to function .in the'well-lrnownmanner, such as, for xanjp'lebyfa conventional thermostat (not shown). However, should faulty operationiof any kind occur in the..system which would result in overheating, for examplegnthe-smoke-pipe 26, or. in thefurnace itself, and an explosion, or pulling should occur, whereby the fire blown open, anda fire result, the fusible elements 28 and 39 would melt, therebyreleasing the lever 21' sothat the valve head 17 of the valve-stem 18 would locate itself in the valve seat 16, through the action of the spring 19, thus instantaneously shutting olf the flow of oil. Since an appreciable amount of'residual 'oilthat has already passed through the valve 15 may remain in the line .betweenthe valve and burner 11, the same would continue toburn for some time if the. burner were .permitted to continue its T'I-Tie principle of operation embodied in the modified switch shown v' box a lever- 3'45 pivoted at 45 carrying a conventional mercury switch 46 connected to lead-in wires 40' and 41. Attthe other end of the arm 34' is an actuating link 47 fire box, a fire box sooner; eieetticjauy controlled burner including an electrically operated blower, a remotely located source dffueh-saifulrfimconnecting said fuel source and, said burner, an electric control circuit for said blower, and metre-pipe connecting said fi'r' box to a chimney; a' :-safetyidev.ice= comprising" a fuel shut ofi valve in said fuel line adjacent said burner and having a valve head mounted on a valve stem extending out of said valve, a spring in said valve biasing said valve to cut oil, position, :a -bmcket l'mounted c 011.! rexterio'r l, of

said valve, .eleet-ricsswiteh tofltheutypeoperited. by mil? iag pivotally =mounted can:said..bra'cket and interposed in saidelectri'eeircuit, lever meanstpivoted to said valve holding said Zvalve open; cable lneans .having' one zend inteljposedmim eable means-at thee-connection oil-said cable meansto said ;st ack ;swhereby upon "disconnection of v the smoke-pipe by explosion or fusion of the-:tfusiblatlifikbypvenheatingthe fuel will cut off and' th electric cir: suit the blower "w '11 b interrupted.

' l -The device of:claimarlain'avhich .asecond pivotaIly connected vto the lever 21 as at'48 and 49. The

'It will thus be seen that the It is also to be understood that the following claims link is provided which-is interposed in said :eable'meine adjacent said .fire .doorof :said fufinace whereby u enfusion .of said link by heatfromsaid fire dooifiid switch and-said valve will be activated to cutotfpositidnsl References Cited 'in-thelfileof this patent

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