US2657742A - Combustion heating control system - Google Patents

Description

Nov. 3, 1953 F. B. AUBERT 2,657,742

COMBUSTION HEATING coNTor. SYSTEM Original Filed July 26, 1943 INVENTOR Jug, ATTORNEY Patented Nov. 3, 1953 UNITED STATES PTENT OFFICE Original application July 26, 1943, Serial No.

496,099, now Patent No. 2,484,602, dated October 11, 1949. Divided and this application September 10, 1949, Serial No. 115,063

2 Claims.

This invention relatesto new and useful improvements in heating apparatus and more particularly to a heating control system therefor.

An object of the invention is to provide a heating apparatus which is particularly adapted for the heating of enclosed spaces in aircraft such for example as the cabin or fuselage.

Another object is to provide a control system for initiating and controlling the burner operating cycle.

Another object is to provide a control by which the supply of fuel is increased upon an increase in the rate of supply of combustion air.

Another object is to provide a control system in which the combustion air pressure controls the starting and stopping of a combustion air blower.

Another object is to provide a control system including means assuring operation of the fuel igniting means prior to the supplying of fuel.

Another object is to provide a control system having a timed control for the heating apparatus.

The invention consists in the improved control system, the cooperative relation of parts and their agroupment in cooperative relation, to be more fully described hereinafter and the novelty of which will be particularly pointed out and distinctly claimed.

In the accompanying drawings, to be taken as a part of this specification, there is clearly and fully illustrated a preferred embodiment of this invention, in which drawing:

The figure shown is a diagrammatic view of an electric control system for heating apparatus.

Referring to the drawings by numerals of reference there is shown a heating control system having an electrically driven timing motor and control therefor. This control system is particularly adapted for use in connection with the heating apparatus shown in my copending application Serial No. 496,099, filed July 26, 1943, now Patent 2,484,602, issued October 11, 1949, of which this application is a division.

In this heating control system there is provided a fuel pump 43'! for supplying fuel to a burner which is not shown. The fuel is ignited in the burner by a hot wire resistance igniter 414. The combustion air for the burner is supplied by either a ram air duct (since this apparatus is designed for use in a moving vehicle) or a blower 430. The blower 430 is normally energized when insufficient ram air is being supplied and is stopped by a pressure responsive switch 43I responsive to ram air pressure.

There is a main switch 400, which is a double lows:

2 throw manual switch having an operating extension or lever 40! operatively connected to its switch arm 402 which is moved to the left, for starting the burner, to engage the switch arm contact with the fixed switch contact 403. The closing of switch 400 completes a circuit from the battery or source of current supply 404 through the lead wire 405 to and through the switch 400 and thence through lead wire 406 to one terminal of the coil 40? of the timing motor controlling relay switch 408. From the other terminal of coil 401, a lead wire 409 extends to the switch arm 4l0 of a normally closed snap acting cam operated switch 4! I. tact 4 l2 of the snap acting switch 4! l a lead wire 413 connects to one terminal of the hot wire igniting means 4 which has its other terminal connected to ground. Operation of switch 400 to close circuit through its contact 403 therefore energizes the igniter 4M and actuates the relay switch 400, provided the igniter circuit is complete and the current supply is suflicient to actuate the relay switch 408. The operation of relay switch 408 pulls the relay switch arm 4l5 into engagement with the fixed relay contact M6 to close the circuit of the timing motor 4!! as fol- From main switch lead wire 406 through lead wire M8, to relay switch arm M5 and its engaged contact M6 to lead wire 419, connected to the closed contact 420 of the normally closed cam operated snap acting switch 42!, having its movable switch arm 422 linked for movement in unison with switch arm 4|0. From the switch arm 422 a lead wire 423 extends to one terminal of the timing motor 4H, which has its other terminal connected to ground by a lead wire 424. Energization of timing motor 4!! drives its cam member 425 to move the cam clockwise, as indicated by the directional arrow, to move cam 420 out of holding relation to the cam follower thrust member 42! so that the snap acting switches 428 and 420 are moved to closed position. Closure of the blower control switch 428 completes a circuit to the combustion air supplying blower motor 430 through the combustion air pressure responsive or ram switch 43! as follows: From battery lead wire 405 through lead wire 432 to the fixed contact of switch 420, and from its cam operated switch arm 433 via lead wire 434, to the normally closed contacts of ram switch 43! and therethrough to the lead wire 435 connected to one terminal of the blower motor 430 having its other terminal connected to ground by lead wire 436. The main switch 400, upon engagement with its contact 403, also controls the motor of the fuel From the fixed conpump motor 431 as it is in series circuit with the low speed fuel pump switchearm-EMZ byziead-wvire 443, connected to lead wire 434. Closure of relay switch 438 engages the arm 442-witn fixed-contact 444, thereby completing the-lcircuit -to.:one

terminal of the pump motor 431-via5 leadrwire1 445 having therein the low speedrresistance flfi, the other terminal of the pump motor beingconnected to ground by lead wire 44?. The heating apparatus will now be in operation at low fuel consumption to supply the desired amount of heat in accordance with the-combustion=air supplyprovided by the blower. Upon increase in' 'the pressure of the combustionair above the-pressure provided by the blower, such-aswvill occurwvhen the vehicle is in rapid movement, theram-switch ,43 I will break circuit betweemthe-blowe'r motor supplying lead Wires '434 and" 435-an-d-willmake circuit from the lead'wireto the lead 446 connected to the switch':arm449 of relay switch 433 arid movable in unison with the-switchar-m 442. Since thesWitch-arm" 449 is in engagement with fixed relay contact 458, the ciscuit=will-becompleted from;1ead wire 448*to the lead'wire '45! which connects to the adjustable contact 452 of the resistance 446,- thereby'shunting out-a por- ;tion of :the:resistance-446 to increase thespeed of. the' fuel pump motor 431, in'order to provide the necessary-quantity-of fuel'for a proper'fu'el airmixture with the increased combustion air upply.

":The 'cam;member 425 has been'rotating 'at 1 a predetermined-rate, preferably a -minute cycle, and when the cam 426 has been-rotated through T90 it will, at "the end-of the five-minute period,

engagellthe followerthrust member 453 to operate the arms 422 and lii'iltoithe'swit'ches'fl I' and-4H respectively to break the tcircuitof *the timer .motor 4!! and of the igniter M4. Although the circuit to the timing "motor' 4l'Tisioroken at-the ,r'elay switch 4&8 upon .opening of "switch 4H which deenergizes the. relay coil 40?, theswitch '42 l provides a safety:control toassure-stopping of the timing motor 4!! inxthe event relay switch 408 should fail to open. .Upon operationasabove described, either at low or'highfuel, consumption vwill not .be aifected by the.time ofoperation of follower member 453 by cam426. Whenit is desired to stop operationo'f the burner,"the-switch operating member 4'lll'is-inoved totheposition .shown in the drawing inwhich switch'arm'4fl2 engages the fixed contact 454 so thatthetimin'g motor MT is reenergized from thebattery'404 through the'following'circuit: From switch contact 454, through lead wire 45'5'toilthe closedcam iswitch 429ian1d thencewiallead-wire 4'56*to"the timinglmotonlea'd wire 423. Accordingly, ifjduringthe. interval of reinstateditimermotor opera- ;tion Lthe combustion air ;pressure ihas decreased below I the predetermined "blower pressure at which ram switch 343I -remakes circuitbetweeni lead wires 434 and 435; the blower'motor43c will ,again' vbe placedin operation to provide scavengingair'forthe combustion chamber. Upon the .termination of the reinstatedoperating'periodof will engage the follower member 421 to open the cam switches 428 and 429 to break the circuits of and stop the blower motor 430 and the timing motor 4H respectively and halting or stopping the cam 426 in its position for the start of an otherlburnerlheating period when desired.

What isrclaimed and zris desiredptol'be secured by'Letters Patent is:

1. A heating apparatus comprising an electric'ally driven blower for supplying combustion air, EaGCiYCllitF'fOT'TSaidTbIOWBI, an electrically driven pump forlsupplying fuel for combustion, a circuit for"said pump; an electrically driven timing motorpzamcircuit for-said timing motor. a cam oper gated rby saidzvmotor, hot wire ignition means for :Tthe supplied fuel, a circuit for said ignition amea-ns;arrelaysswitch controlling the circuit of said motor and having its coil in series circuit with said ignition means, a pump controlling relay switch having an operating coil, a blower and '-'-pum-p --sv;r'itch opera-ted -"by sai'd cam 1 :upon stai'ting of ==said 'motor aanidccontrolling :the-l' circuits of said "pump and said blower, said I cam acting upon predetermined running of said'motcr to open "said" blower and pumpswitch, arpairr:of normally closed switches controlling the-"circuit of said motor-and the=:circuit rofisaid-ignition means arid- -movable:to open position byisai'dcam upon predetermined 'running :of said "motor, :a double-throw switch operable in one positionzto close the circuits 0f said r-elay'coiland :saiot oper- -dting 'coil-::arid :operable in the :other position .to close a circuitin 'shuntavithzsaid =cam'opened 'motor switch f thereby to frein'state operation of said timing motorfor predeterminc'd Lclosure :of the-blower circuitp and a switch ropened'vbys'said cam' to deenergize saidtiming motor: upon:o.pen-

ing of said blower-"switch by" said :cam.

'2. A heating apparatus *comprisingcanfelectri- "caliydriven blower 'fon supplyingccmbustion;air, a circuit i for" said blower, an :electrically r-driizan pump for supplying fuel for combustion, low and high-speed 'circuitsTorsaid 'pumppan electrically driven timing motor, "a circuit for 1 said :timing *motor, a cam operated :by' said motor, rhot'wire ignition means 'for the supplied :fuel, ea :circuit "for said ignitionmeans,aa'irelayrswitchcontrolling the circuit of said motor and:having its'coil *in seiies circuit with said ignition 'means,:a relay switch having an'oper-ating' coilrearrdhavingnormally open contacts controlling the lower speed circuit of said pHmpE'fQr low specd operationand having normally 'open xcontacts :controiling "the highspeed circuit of said pumpfforhighspeed operation, a 1 pressure "responsive switch fhaving i normally closed r contacts controlling the circuit 'of saidblower'and having normally openicontacts controlling the circuit to: said high speed: pump open contacts; said responsivetswitch 'acting-zat predetermined increased combustionair pressure to open its normally'close'd contacts and "to :close its normally open-contacts, 9a xblower'and pump switch operated by SZiClECEJm uporrstarting. of said nrctcr an'clucontrollingcthe circuitszof said pump and said blcwenasaidmam acting'lipongpredetermined runningro'f; sai'dimotorrto .opensaidzblower and ipump switch, zay pair of normally closed zswitchesmontrol'lingithenircuitioisa-idzmotoraand thei'circuitzofzsaid. ignition means-and movableto *open position I-by :said :cam upon predetermined "running 'of sisaid :motor, .a fiouble-lthrow ."switch roperableinwne position ;to ;,close..the:.-circuits of --s-aid-relay1coil anrlzsaidz-operatingc coil and; operable in the other positionatovclose-aicircuitlin 15 minutes of the timing *mQtor'M-"I; the cam' 426" ?Shimt with.saidicam;cpenedrmo on wi v y to reinstate operation of said timing motor for by said cam.

FRED B. AUBERT.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date Carlson July 12, 1927 Number 6 Name Date DArche June 12, 1928 Booth Dec. 4, 1928 Parker Sept. 13, 1932 McCabe Nov. 29, 1932 Fox Sept. 25, 1945 Bower Mar. 25, 1947 Smoot Aug. 17, 1948 Aubert Oct. 11, 1949

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