US2132980A - Stoker construction - Google Patents

Description

'r. R. WOOLLEY El AL 2,132,930

' Oct. 1-1, 1938.

STOKER CONSTRUCTION Filed Jan. 16, 1934 I 2 Sheets-Sheet 1 INVENTORS 720m 051?- 4 M a/ mi:

ATTORNEYS Oct'. 11, 1938. I T. R. WOOLLEY ET AL 9 STOKER CON TRUCTION Filed Jan. 15, 1934 2 h ets-She t 2 .47 L w 1 GL- 5 I INVENTORs ATTORNEYS Patented Oct. 11 1938 UNITED STATES PATENT OFFICE STOKER CONSTRUCTION Thomas R. Woolley and Fred Hammis, Detroit,

Mich.

Application January 16, 1934, Serial No. 706,880

3 Claims.

veyer is utilized for feeding fuel from a suitable source such as a hopper to the air feeding means. Another object is to provide a stoker wherein both the blower and conveyer aforesaid are operated by and driven from a single'source of power such as a suitable electric motor. I

Another object is to provide a stoker wherein the driving connection between the.motor and conveyer preferably includes an adjustment for varying the movement of the conveyer so that the quantity of fuel transferred from the hopper to the air feeding means may be varied as desired. Another object is to provide a stoker wherein adjustable means is provided in the air'feedingmeans for varying the volume of air used to feed the fuel into the furnace.

Another object is to provide a stoker which is aself-contained portable unit and may be convenientlvmoved to and from one or more furnaces as desired.

Another object is to provide a stoker wherein the conduit for the air used in feeding fuel into the furnace is so constructed that its withdrawal from the furnace upon movement of the stoker as aforesaid will leave the furnace intact so that it may be fired by hand.

Another object is to provide a stoker wherein the air feeding means is provided with an adjustment to compensate for any irregularities'in distance between the stoker and furnace when the stoker is moved from one furnace to another along the track. I

Another object is 'to provide a stoker wherein all of the working parts except a nozzle upon the air conduit aforesaid are outside the furnace and are readily accessible.

Another object is to provide a stoker wherein the spiral conveyer and its enclosing conduit are so constructed and arranged that a bed of fuel of suifieient depth 'is provided on the bottom of the conduit beneath the conveyer to receive and insulate the conduit from themain body of moving fuel and slate or other foreign matter carried by such body which otherwise might have an abrasive action or damaging effect upon the metal of the conduit,

(01. no -11o Another object is to' provide a construction wherein means in addition to the stoker is provided for feeding air into the furnace beneath the grates thereof while the blower aforesaid is operating or while it is idle to assist in the combustion of the fuel fedinto the furnace.

Another object is to provide a construction wherein the supply of air to the fumace is automatically controlled but may at will be manually controlled.

Another object is to provide a construction which is simple,practical, scientific, efficient and economical in operation and which produces practically smokeless combustion,

.Other objects, advantages and novel details of construction of this invention will be made more apparent as this description proceeds. especially when considered in connection with the accompanying drawings, wherein:

Figure 1 is a perspective view of a furnace and a stoker embodying'our invention applied thereto;

Figure 2 is a fragmentary vertical sectional view taken through the construction illustrated inji'igure 1;

Figure 3 is a sectional view taken on the line 3-3 of Figure 2;

Figure 4 is a sectional view taken substantially on the line 4-4 of Figure 1;

Figure 5 is a horizontal sectional view taken on the line B'-5 of Figure 2; v

Figure 6 is a sectional view taken on the line 6-6 of Figure 5;

Figure 7 is an enlarged fragmentary vertical sectional view through the juncture of the fuel 35 and air conduits;

Figure 8 is a diagrammatical view of the electrical system;

Figure 9 is a sectional view taken on the line 9 9 of Figure 4.

gure 10 is a sectional view of a detail on a larger scale.

Referring now to the drawings,' A is a furnace of conventional design and B is .a stoker embodying our invention for feeding fuel into the furnace. In this connection it is to be understood that the furnace may be any suitable type with which a stoker' embodying our invention may be associated.

As shown,'the furnace A has a flre box or combustion chamber I provided with a suitable fuel feed opening 2 and door 3, an ash pit 4 provided with a suitable opening 5 and door 6, grates I for supporting the-fuel'bed 8, a shaker mechanism 0 for the grates, a stack or smoke pipe trained around the pulleys 33 and 35.

III, a stack control switch II, a water gauge l2, a low water cut-off switch l3, and a steam pressure switch l4. It will be noted from Figure 8 that the thermostatic switch llnand steam pressure switch M are connected in parallel and that the low water switch 13 is connected in series with the two above switches.

The stoker B is a self-contained portable unit and is preferably movable upon a suitable track I5 in front of the funace A. If desired, this track |5 may extend in front of more than one furnace so that the stoker B may be moved thereon from one furnace to another, consequently it is possible for the same stoker to be used for firing several furnaces at different times.

Referring now in detail to the stoker B, I6 is a casing having legs l1 provided at their lower ends with casters or rollers l8 for engagement with the rails of the track |5. I9 is a blower or fan housing upon one side of the casing I6 and having a suitable inlet 28 and a suitable outlet 2| for air, 22 is a fan in the housing I9, and 23 is a shaft for the fan extending into the casing I6.

24 is'a sectional conduit extending from the air gitudinally of the conduit*28.. 30 is an electricmotor within the casing l6 connected directly to the fan shaft 23 and having a shaft 3|, 32 is a housing for suitable reduction gearing, 23 is a pulley rigid with the drive shaft 34 of the.reduction gearing, 35 is a spring pressed pulley-on the motor shaft 3|, and 36 is an endless belt 31 is a change speed mechanism for the belt drive, 38 is the conveyer 29.

the take-oil? shaft of the reduction gearing, $39 is a gear on the take-off shaft 38, 48 is a shaft for the spiral conveyer journaled in bearings 4| and 42 respectively at opposite ends of the conduit 28, 43 is a gear rigid with the conveyer shaft 40, and '44 is an idler gear between and meshing with the gears 39 and 43. Thus, it will be apparent that both the conveyer 29 and fan 22 are driven from the motor 38. Preferably the connection between the gear 43 and shaft 48 includes a .pin 45 whichis shearable' when subjected to undue strains or stresses. Likewise, the construction and arrangement of the spiral conveyer 29=-relative to the conduit 28 is such that a bed 46 of fuel of suflicientdepth is provided on 49 and 58 respectively therein through which-thev fuel from the'hopper passes when actuated by The conveyer 29 terminates short of the opening 50, consequently fuel from the hopper will ordinarily not be carried beyond said opening. However, if for any reason the fuel should be carried-or moved in the conduit 28 .beyond the opening 58, it will be returned to said opening by an auxiliary spiral conveyer 29' 28 aboutthe shaft 48 beyond the opening. .The section 5| carrying the nozzle 26 is detachably connected to the door-3 so that it may be readily withdrawn when it is desired .to move the stokerrelative to the boiler. Preferably this'is accomplished by providing a fixed collar 52 upon the section 5| for engagement with the outer side of the door and by threading a flange 53 of the nozzle 26 upon the free end of thesection 5| against the inner side of the door. The nozzle 26 may be of any suitable construction but preferably includes an elbow 54 and an adjustable deflector 55 which are so constructed and arparent that this section 56 may be uncoupled from either section 41 or 5| to permit the door 3 carrying the section 5| to be opened for access to the nozzle 26 when the stoker is to be moved relative to the furnace.

Preferably the air outlet 2| converges from the fan housing I 8 so that the pressure of air from the housing is built up before it reaches the conduit 24. Moreover, a baflie- 51 is provided in the section 41 of the conduit 24 which extends downwardly and forwardly of the fuel opening 49, and is constructed and arranged in such a way that it cooperates with the conduit 24 to form in effect a restricted orifice for the air. As a result, the air from the blower will rush with great velocity past the baflle 51 through the conduit 24 to the nozzle 26 and will serve efliciently mounted on a wall 58 of the conduit 28, hence may be raised or lowered at will relative to the bottom of the conduit 24. a result, the velocity of the airmay be varied as desired. It will' also be noted that a damper 68 is provided for closing the air outlet 2| when the fan 22 is not operating. Preferably the construction is "such that the damper 60 will be held in open raised position (full lines, Figure 2) by the air when the fan is operating and will fall by gravity to closed position (dotted, lines, Figure 2) when the fan 22' stops.

' In the present instance air is blown into the ash pit 4-beneath the grates I by means of a fan 6| within a suitable housing 62 so that the air will filter upwardly through the fire bed 8 and assist'in the combustion of the fuel. As shown. the housing 62 has an air inlet 63 at one side pro- 1 vided with a manually operable damper 63' to control the volume of 'air admitted, and has a damper controlled outlet 64, a spring 65 being provided to insure proper closing of the damper 66 when the fan 6| is not operating Preferably a separate motor 61 is used to drive the fan 6| and is mounted on a suitable base 68 beside the housing 62.

In order, that the supply of fuel and air to the furnace A'will be controlled automatically, we

have electrically connected the motors 38 and to both motors 38 and 61 and cause them to stop, and is operable when the steam' pressure falls upon the casing I.

to a predetermined low pressure to close the circuit to both motors and cause them to actuate the fans 22 and 8| and conveyer 29. The stack control switch II is a conventional thermostatic type which is operable'when the heat in the stack |8 reaches a predetermined high temperature to open the circuit'to both motors 38 and 61 and cause them to stop, and is operable-when the heat in the stack l8 falls to a predetermined low temperature to close the circuit to both motors 38 and 61 and cause them to actuate the fans 22 and GI. This stack control is primarily a night control and effectively prevents the fire from going out.

The low water linecut-oif switch 3 is also a conventional float actuated type-which. is operable when the water level falls below a predetermined point to open the circuit to both motors 38 and GI and cause them to stop, and is operable whenthe water level rises to a predetermined point to close the circuit to the motors 38 and- 61 and cause them to actuate the fans 22 and'G Preferably this switch I3 is located approximately one inch above the bottom of the water gauge |2 on the boiler.

In addition, we have provided three manually :operable switches 88, 8| and 82 respectively.

Preferably the switch 88 is in the shunt circuit tothe steam pressure switch l4. when opened. this switch 88 cuts, out the steam pressure switch H. When closed, the switch 88 permits the steam pressure switch ll to. function. The switch 8| is in the circuit to the motor 38, and the switch 82 is in the circuit to the :motor 81. Hence when the switch 8| is opened,the motor 38 will be stopped and the supply of both fuel and air overthe fire bed 8 will be stopped. When the switch 82 is opened, the motor 81 will be stopped, consequently the supply of air under the grates 1 will be stopped.

In operation, the hand switches 88, 8| and 82 respectively are normally closed, hence the stoker is normally automatic. As a result..fuel and air are supplied to the furnace over the fire bed 8 and air is supplied to the furnace beneath the fire bed simultaneously. However, at times the fuel bed is too thick for good combustion. We then open the manual switch 8| and allow the fan 6| blowing airbeneath the grates to continue operating until the fuel bed is the desired thickness for best combustion. The mechanism 31 and baflle 51' are then' adjusted properly to accomplish the desired results. In this connection it will be noted that the mechanism 31 is a change speed mechanism and comprises a pulley 31 engaging the belt 36 and carried by the forked head:31 of a supporting screw 81 extending upwardly through a block 31 mounted An adjusting wheel 31 threadedly engages the screw 31 above the block 31 and carries a pin 3l which engages an annular groove 31' in the block. Thus, rotation of the wheel 31 about the block 81 will cause the 'screw 31 and pulley 81 to be raised orlowered. I

. The pin-31 engaging the slot 81' in the block 31 will permit-such rotation of the wheel 31, but

'tached to such third furnace.

will prevent displacement of the wheel from said block. Referring to Figure 5, it will be observed that the pulley 35 has separate sections 35* and 35'. Section 35" is rigid with shaft 3|, while section 35 is splined upon said shaft and is urged toward section 35 by a coil spring 35 located between said section 35 and a block 35 anchored on said shaft 3|. Preferably the arrangement is such that the section 35 may be moved away from section 35 by the belt 36 when the pulley 31 is raised by adjustment of the wheel 31. Likewise when the pulley 31 is lowered, the

section 35' will be moved by the spring 35 toward in the furnace through holes in the fuel bed. We

then open the switch 82 controlling the motor 61 to cut ofl the supply of air beneath the grates, at the same time allowing the motor 38 operatingthe conveyer 29 and fan 22 to continue operating so that the supply of coal and air over the grates will continue until the desired thickness of fuel 'bed is obtained.- The mechanisnrfl and bailie 51 are then adjusted properly for efficientresults and following this, the switch 82 is closed so that the operation will again be fully automatic.

Normally. switch 88 is closed during operation of the stoker so that the steam pressure switch M will operate. However, when normal conditions are not required, for example, during the night, this switch 88 is opened so that the steam pressure switch ll'will be cut out. The

stack control switch. functions to maintain a certain stack temperature and in doing so controls the circuits to the motors so that sumcient combustion takes place to prevent the fire from going out. When the, water gets too low in the boiler, then the low water cut-off switch will function to open the circuits to the motors and cause the fans and conveyer to stop operating. In the evenfiof failure of the electric service,

or damage to the stoker, the latter may be moved away from the furnace so that the furnace may be med by hand. This is an important factor in greenhouse work, power plants, schools, apartments, etc. Moreover, it is a big advantage to be 'able to move the stoker from one furnace to another for any reason such as failure of any one furnace. In this way only one stoker is required for several furnaces. For example, where two furnaces are necessary to carry the load and a third is used as a standby, then only two stokers of the type herein describedv are required. When the third furnace is wanted in service, one of the two 'stokers mentioned can be moved and at- When the circuit to the motor 88 is closed, air at sumcient velocity, volume and pressure from the fan 22 passes through the conduit 2| be- .neath the baflle51, picks up the fuel dropped from the conduit 28 and carries it,to the nozzle 28 where it is projected in spray form into all parts of the fire'box upon the fuel bed. The fine particles of the fuel' are to a large extent burned in suspension. The larger particles fall onto the fuel bed. Inasmuch as the mechanism. 31 controls indirectly the speed of rotation ofv 'tion thereof. In this connection it should be noted that the nozzle and/or deflector 55 can be turned relative to the section 5| to throw fuel down one side orpthe other of the flre box, as desired. Actually thenozzle is so shaped that it functions to throw the fuel and air to all parts of the fire-box. The high vele-cityof the airprodnces the necessary turbulence within the flre box to cause thordugh commingling of the air and fuel for the most eflileient combustion. Thus, it is possible with our stoker to feed simultaneously the correct amount of fuel and air at the correct volume and pressure above the grates and t the same time to feed the correct amount of at the correct volume and pressure beneath the grates. v

What we claim as our invention is:

1. The combination with a furnace having a heating chamber, of apparatus for feeding fuel into the heating chamber comprising a blower located exteriorly of the chamber means establishing communication between the blower and heating chamber including a conduit, a fuel hop= per located between the blower and said chamber I and communicating with said conduitto discharge fuel into the air stream passing through the conduit, means located between the blower and 'point of communication of the hopper with said conduit for varying the rate of flow of air through said. eonduit, said last named means including a damper having a portion extending into the conduit and inclined from one side wail. of the conduit in a direction toward 'said. chamher, and means supporting the damper for sliding movement relative to the, conduitto vary the clearance between one edge of the damper and the side wall of the conduit opposite the wall aforesaid and effective to' maintain the angle of inclination of said portion of the damper with the air stream substantiaily. constant in several of the adjusted positions of the damper.

2. The combination with a furnace having a heating chamber, of apparatus for feeding fuel into the heating chamber comprising. a blower located exterlorly of the chamber, means establishing communication between the blower and heating chamber including a conduit, a fuel hopper having a discharge opening communicating with the conduit at a point between the blower and heating chamber for discharging fuel into the air stream passing through the conduit. means located within the conduit adjacent the discharge opening of the fuel hopper for varying the rate of flow of air through the conduit and for directing the fuel into the air stream, said last named means including a damper having a portion inclined from one side wall of the conduit in a direction toward the heating chamber and positioned with respect to the discharge opening of the hopper to direct fuel into the air stream flowing past said damper, and means for adjust ing' the damper relative to the conduit to vary the clearance between the side wall of the conduit opposite the side wall aforesaid and effective to maintain the angle of inclination of said portion with the axis of the hopper discharge opening substantially constant in several of the adjusted positions of the damper.

3. The cornbinationwith a furnace having a heating chamber, of apparatus for feeding the fuel into the chamber comprising, a blower' located exteriorly of the chamber, means establishing communication between the blower and heating chamber including a conduit, a fuel hopper having a ,discharge opening communicating with said conduit at a point between the blower and heating chamber, means located between the blower and hopper discharge opening for varying the rate of flow of air-through said conduit,

said last named means including-a damper hav-.

ing a portion inclined downwardly from the upper side of the conduit in the direction of flow of air through said conduit and located in said conduit adjacent the hopper discharge opening to provide a chute for directing fuel into the conduit in the air stream flowing past the damper,

and means supporting said damper for sliding movement in a direction parallel to the axis oi the discharge. opening for varying the clearance between the iower edge of the damper and adjacent of the conduit without changing'the angle of inclination of the portion aforesaidof said THOMAS R. WOOLLEY.

FRED HAMMIS.

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