US1996230A - Fuel burning system - Google Patents

Description

April 2, 1935. R. E. BRESSLER FUEL BURNING SYSTEM Filed June 27, 1951 55km, mu w N n WH automatically proportioned to the requirement of the 'amount ofv fuel being: burned and in such. manner that' the volume or amountof coal to bev inuifned through any length of time willbe con trolled through control 'ofV the .volume of air..

Patented .Apn 2, 1935 BURNING SYSTEM .Robert E. Bressler. Oregon, *u u Aspiieauen .ma "27.1931, seringue; 547;:03" s zclaims. (01.., 1104445 My invention relatesto an improvedymethod and arrangement for economically' and efliciently burning 'fuel' such as coal and is particularly use-.-

lul and-efficient in :connection withrstoker fed.:

'furnaces'where a. power driven stokerandA a power driven blower delivercoal and air to a burner.. `orre'tort within a furnace. s

An important object-cf .the invention is to provide improved 'arrangementand' control whereby the volume ofair may be exactly and i thus making it possible to feed any given quantity 'of coal tofthe .fire'through the control cf the volume of air. '1. A further' yobject is to provide an arrangement andcontrol-whioh gives'a means for variable adjustment `of depth of fuel bedjon the Stoker to suit the demands of the-heating or-powe plant under 'all conditions. Another object is to provide a -method of con,-

trol of combustionconditions which are .entirely independent of the operator and which provides air in'only suflicient quantities for the proper and efilcient Vcombustion of the; vfuel fed .te the furnace, 1 A further object is to provide an arrangementand means `vliereby the. airpressure in 4the air path from the blowen tothe burner Vwill control the stolzer operation'in such a manner as to as'- sure a predetermined xed depth ci fuel bed.

A still further object is to provide controlling `apparatus for the stolzer .dri-ving motor circuit whose operation is controlled by the staticor back `pressure in the airline caused by theY resistance to the air iiow throughA the fuel bed,` together with manually adjustablemeans for limiting the volume of` air delivered by the .blower to the burn- 1er to thereby govern the ra-te of combustion and to assistiin governing the amount of time that-A the feeding motor .willoperate l A'still furtheriobject is to provide a system which the. coal feedingstokeris always .driven .at

thevsame rate .by the driving motor and in which 'the' operation of the motorv is automatically con.

' trolled 'bythe volume of air -deliveredto the burnerbytheblower.'.- In addition tothe abovespecically ref erredto features the invention includes other. `features, all

of which will becomezappa-rent from the following.

specification in connection with. the drawing,

on which drawing Figure 1 -isa plan view .more or less diagram-y plate 9 surrounding .the chamber.

matic of the system'involving the stolzer vmechanism, the blower, andthe driving motorandcontrol elements; 1 Y Figure 2.is anenlarg'eddiametral. section of the governor circuit controlling device.

On the drawing, I represents the .mbox'bf a furnace to. be .supplied by coal from the stoker structure A whichmay be iwanyfvfvell. kn'ovn design. rl'fhe structure .shown comprises a coal -hopper Z from which coal isffedto bereceived' by a feed screw or otherieed element (not ShOWn) operating .in the barrel 3 leading to theburner or retort 4 within thev re'box', a speed reducing gear structure indicated by 5 being connected A xr/'ith the feed elementaml beingadapted to driven by an electric motor 6." 1

The 1 burner l o1- retort f may be 'of .any'. suitable construction to provide the ,chamber j'fcr receive ing the coal from the feedelexnent. andhaving tuyreswor ports. .8 for conducting .faiif-"into'v the coal within the chamber 1 and fed overj'the dead .A blower structure B is connected by a duct "lll with the airspace formed below the b'urnerstruc- `ture by a wall IIandin this du'ct isinterposed an adjustabledamper l2. .Inthe arrangement of Figure 1;theblower. is` driven bythe motor 6 which serves also .to drive the gearing 5. for the stoker mechanism, and a magnetic clutchlllmay be interposed between vthe motor and thegearing. The current supply leads lj'and I 9 for the motor lare adapted for connection with tlie supply circuit 20 by asuitable magneticswitch indicated at'fll which may. be of any f well'. .known construction,

andthe operation oi the' magnetic switch to. connect the mctorcircuit with the 'supply circuit may `be controlled by adevice indicated at which is thermally or pressure controlled. Wherethe furnaceA is usedfor heatingpurposes the temperature of theheated space v vill determine the operation of the control device 22and where the'furnace is used for heating` a,boiler. jthe steam pressure may function to controbthe operation of the device. I The d evice fon automatically controlling the loperationfoi `the stoker mechanism by the motor 6 is clearly shown Figure 2.'. Itcornprises upper and lower housing sections 23 and!! which secure betweenthem theperipheral portion oi'"a diaphragm 2 5L The 'chamber above the diaq phragm is connected by a duct 28 with the'air delivery duct l0 fromthe .blower as' shown in the arrangement offFgures 1 and 2. A stem 21 is secured tothe diaphragm at the central part .thereotand has its upper Gnd guided by a spider 28 secured to the housing VM .xtdjacent to theduct 2U.

The lower end of the stem extends through the headof a hollow plug 29 which has adjustable screw threaded support in the housing part 24. The plug receives a compression spring 2| whose one abutment is the head of the plug and whose other abutment may be a disc or collar 32 secured to the diaphragm I0. f

At its lower end the diaphragm stem connectsl with'the'end 'of a rocl; frame 32 pivoted on a bracket 24 and supporting a mercury switch tube 25. In the arrangement of Figure 1 the contacts of the switch 3l are connected in series in the supply circuit ll-I! which also includes the magnetic clutch l1, the motor 8 being connected directly with the supply circuit in advance of the switch contacts. To open or close the clutch circuit independently of the other switch contacts, a hand switch 28 may be included in the supply circuit Il-IS.' i y 'Ihe blower B is provided with air volume regulator means or air damper 42 which may be set for any desired volume of air supply for the burner.

Describing now the operation, when the pressure .above the diaphragm 25 is insuicient to de- `ect the diaphragm against the pressure of the 'spring Il, the mercury switch Il will be in its cirthereby. Suppose cuit closing position as indicated on Figure 2. However, when the spring is overcome by the pressure against the upper side of the diaphragm the diaphragm will be deflected downwardly and the mercury switch will open the circuit controlled that the system is at rest with the-thermal or pressure control device 22 holding the magnetic switch 2l open so that there will be' no current flow to the system. Then, in the 1, the motor t is disconclutch l1. Should the device 22 be now rendered eiective by heat or pressure to cause closure of me magnetic switch, the circuit lc-Is .will be connected with the current supply circuit and the motor will operate vto drive the blower so that air will be charged into the furnace below the burner. and the-mercury switch I5 being also closed, the

The hand switch $4 being closed magnetic clutch will also connect the motor 8 for I, drivingthe stoker mechanism.

`below the burner or retort or less resistance,

As the air from the blow'erenters the space and owa therefrom through the tuyre passages l, it encounters more depending upon the depth of the fuel bed through which the air must travel. 1f, when the system is started, there is very little coal onthe burner and the resistance to the air flow is correspondingly low, Ipressure created in the blower duct will be insumthe static or back cient to deflect the diaphragm and the switch 35 remains closed and the motor continues to drive the stoker. As the supply of coal to the burner increases the. resistance tothe ,air increases and eventually the static or back pressure will become suillcient to deflect the diaphragm and to cause movement of the mercury switch to open the magnetic clutch circuit so that the stoker will no longer be operated and coal feed will stop. As `the coal burns away on the burner, the resistance to air flow through the fuel body correspondingly diminishes and the reduced static or back pressure will no longer be able to hold the diaphragm against the pressure of the spring 2| and the diaphragm is therefore shifted to cause reclosure of the mercury switch and reconnection of the magnetic clutch inserted so that the motor may again drive the stolzer to feed fuel to the burner.

If the damper I2 is omitted or has been set to be full operation of the blower, the furnace will be operating at maximum capacity, the coal bed on the burner aording the only resistance to the air ow, the adjustment of the diaphragm spring being such that under these conditions the static or. back pressure will be suiflcient tc deflect the diaphragm to cause opening of the mercury switch only when the maximum amount of coal has been stoked to the burner. l

As soon as` some ofthe coal burns away and the back or static pressure is sufciently reduced the diaphragm device again closes the circuit so that the fuel feed to the burner will be automatically maintained in properproportion with thelair delivered, or vice versa., the amount of air delivered will be in proper proportion to the amount of fuel delivered to the burner so that the most efficient combustion will result.

If it is not desired to work thefurnace at full capacity, the regulator 42 is set to reduce the air volume delivered per unit oi' time to the burner, and under these conditions the back or static pressure will become effective on the diaphragm before the maximum amount of fuel has been fed to the burner and the circuit controlling the operation of the stoker will be opened and held open until the fuel has been burned away sumciently to reduce the resistance to the air flow to a point where the back or static pressure can no longer hold the diaphragm down. After setting of the regulator 42, the operation of the system will be entirely automatic, the volume of air being exactly and automatically proportioned to the requirement of the amount of fuel being burned and in such manner that the volume or amount of coal to be burned through any length of time will be automatically controlled through control of the volume of air, thus making it possible to feed any given quantity of coal to the nre through the control of the volume of air by means of the regulator 42. If a very low fire is desired, as for example, during the night, the regulator 42 is set for the necessary restriction of air delivery, and thereafter the diaphragm device will control the system so that the stoker will supply coal in proper proportion to the admitted air for eillcient and complete combustion. Should the furnace or boiler deliver too much heat or too much pressure, the automatic controlling device 22 will function to disconnect the supply circuit until the heat or pressure has been properly reduced and it will cause reclosure of the circuit and the system will then proceed to operate under control of the diaphragm device in the manner explained.

Instead of using only the regulator 42 for controlling the air volume delivery by the blower B, the damper l2 could be used for accomplishing the same end, or both the damper and the regulator might be utilized. The regulator 42 may be set for a maximum air delivery under which the system is to be operated and the damper I2 then adjusted for the desired modification of the air delivery. When the damper is wide open, the system will operate at maximum capacity determined by the setting of the regulator 42, and if the damper is partially closed its resistance to the air delivery will be added to the resistance of the fuel bed to the air flow therethrough and the back pressure will be built up more rapidly and the diaphragm will be deflected and the stoker driving motor disconnected from circuit with a shallower fuel bed on the burner than would be'the case if the damper had not been adjusted to restrict the air flow, so that by adjusting the damper the volume of fuel delivered tothe burner will be diminished and in accordance with the damper restricted air ow.

The volume of air delivered to the burner will control they amount of coal burned, and the operation of the diaphragm structure will determine the depth 'of the fuel bed on the burner. By adjusting the plug 29 and thereby the resistance effort of the spring 3| against deflection of the diaphragm 25, setting is readily made for the maximum static or back pressure at which the stoker motor is allowed to operate. Adjustment to increase this pressure will result in a deeper fuel bed and adjustment to decrease the pressure will result in a shallower bed. As more or less air is delivered to the burner, it will be necessary to readjust the spring tension on the diaphragm in order to maintain the same or a different depth of fuel bed due to the fact that as more air is admitted to the burner or forced through the burner, a greater resistance will be caused-by the attempt to force a greater amount of air through the same depth of fuel bed, and conversely, less resistance will be created by forcing a smaller volume of air through a certain depth of fuel bed.

It will be noted that with my improved arrangement and control no adjustment is required for the speed reducing mechanism 5 but the stoker is always driven at the same rate of speed whenever the motor operates. Likewise the blower is always driven at the same rate of speed when the driving motor therefor is connected in circuit. If it is desired to stop the stoker at any time during operation of the system, the hand switch 3i (Figure 1) may be opened.

My improved system and method of burning fuel is very simple, and being entirely automatic it requires very little attention, and it effects considerable saving in fuel and in operation costs.

I have shown practical and efficient embodiments of the features of my invention, but I do not desire to be limited to the exact details shown as changes may be made in arrangement and operation without departing from the principles and scope of the invention as defined in the appended claims.

I claim as follows:

1. In combination, a retort adapted to have a bed of fuel thereon, an air chamber beneath said retort, a blower, a conduit connecting said blower and the air chamber to supply air through the fuel bed, a stoker, an electric driving motor operatively connected with said stoker, an electric circuit operatively connected with said motor, and means responsive to the resistance to air flow through the fuel bed adapted to start and stop said driving motor, said means including a diaphragm chamber operatively connected with said conduit, a spring-pressed diaphragm in said diaphragm chamber, and a switch in the electric circuit operatively connected with said diaphragm to be opened and closed thereby.

2. In combination, a retort adapted to have a bed of fuel thereon, an air chamber beneath said retort, a blower, a conduit connecting said blower and the air chamber to supply air through the fuel bed, a valve in said conduit movable to variably impede air flow through said conduit, a stoker, an electric driving motor operatively connected with said stoker, an electric circuit operatively connected with said motor, and means responsive to the resistance to airflow offered by the fuel bed and by said valve adapted, to start and stop said driving motor, said means including a diaphragm chamber operatively connected with said conduit at a point between said blower and said valve, a spring-pressed diaphragm in said diaphragm chamber, and a switch in the electric circuit operatively connected with said diaphragm to be opened and closed thereby.

ROBERT E. BRESSLER.

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