US1783821A - Heater control - Google Patents

Description

Dec. 2, 1930. G. D. BARKER 83, 1

HEATER CONTROL Filed June 15, 1929 YW'Q 57 m 9 M N Patented Dec, 2, 1930 GALEN n, BARKER, or DOWAGIAO, MICHIGAN;

HEATER common Application med June 15 This invention relates to controlsfor heaters and more especially to a furnace or boiler control utilizing damper mechanism for regulating the combustion in the boiler or furnace.

One" of the principal objects of the present invention isto provide a control of this character which exercises positive and effective associated.

control over the draft through the fire and in the stack thereby providing for such comblistion as may be needed to meet the require ments of the system with which the heater is Another object of the present invention is to provide a device of this character which is of simple and durable construction, reliable and effective in operation and easy and com-- paratively inexpensive to manufacture.

In carrying out the present invention an automatic check draft damper is built into the stack or chimney and is so constituted as to automatically open and close in response to the draft through. the stack. Thus, if the draft through the stack exceeds a predetermined point it sucks the checkdraft damper open with the result that cold air feeds directly into the stack, coolsoif the gases and cuts down the draft thereby retarding combustion in the heater. The" check draft damper is'preferably in theform of a freely ivoted. balanced damper biased by an ad uStabIe weight to" closed position. 'In conjunction with the weight, an additional or auxiliary biasing means is employed and is-under the control of a room thermostat so that when the room thermostat is calling for heat the auxiliary biasing means will'cooperate yith the check draft damper to apply an additional yieldable bias thereto which tends to hold the same closed notwithstanding the influence ofa draft through the stack that tendsto open'the' same. However, if the draft through the stackattains such proportions as "to be liable to generate in the heater'more heat than can'be absorbed with safety and efficiency in the system then the check draft damper will open notwithstanding the action of its weightand of its auxiliary biasing means, the. auxiliary biasing means yielding 1929. Serial No. 371,075.

to permit openingof the check draft damper under such circumstances.

Organized'with the check draft damper is a I positively controlled direct draft ,dam er. This 'direct draft damper is incorporate in the ash pit structure and is suitably biased to closed position as by a weight. For opening the check draft damper a conventional regulator, such as a diaphragm regulator, is

provided, the regulator being connected'to the dome of the furnace and acting to swing)a weighted lever havingan arm connected a chain to the weighted arm of the direct draft damper. In this way the condition of the heating medium in the boileror furnace regulates the opening and closing of thedi- .I'ect draft damper and does this positively.

. This is especially advantageouswith banked or slow burning fires where positive opening of the direct draft damper is desirable in order to accelerate combustion.

I Other objects andad'vantages reside in certain novel features of the construction, arran'gement andcombination of parts which will 'be hereinafter, more fully described and particularly pointed out inthe appended claims, reference being had to the accom panying drawings forming specification, and in which: Figure lis a view illustrating one embodiment 9f the invention partly in side elevation and partly in vertical section taken on line a part of this 11-. of Figure 2 andwith parts broken away and parts omitted for the sake of illustration Figure 2 is a View in front elevation of the check draft damper andits controls;

Figure 3 is a fragmentary view in section taken on line 33 of Figure 2; and

Figure 4 is a similar view taken on line of Figure 2. o

Referring tothe drawings, the'numeral ,1

designates a heating lant which may be of any conventional or own type, such as a hot air furnace, a'hot. water, a steam or va or boiler, a gas fired furnace or an oil fired uruse on any of the various types of heating plants. The combustion space of the heater connects by a smoke-pipe 2 to a stack or chimney 3. 7

race. The present invention/is adapted for An opening 4 is cut in the stack 3 and receives and supports a reduced extension 5 of a box-like casing 6, the casing 6 being suitably secured in the position shown in Figure 1. Both ends of the casing are open, the inner end having direct and unobstructed communication with the interior of the chimney and the outer end communicating with the atmosphere under the control of a check draft vane or damper 7. When the damper 7 is open air freely flows into the stack 3 to provide a check draft thereinto which, because of its venting action and also because of its cooling action on the gases in the stack, cuts down the draft through the stack and the amount of air pulled through the fire and consequently retards combustion in the heater.

The damper 7 is freely pivoted on the end wall of the casing 6 by means of offset -01 eccentric pivot pins or trunnions 8v threaded through the end walls of the-casing and extending into sockets or bearings 9 provided on the damper. Because the damper 7 is so pivotally mounted, the draft acting on the larger area thereof below the pivots or trun nions 8 tends to swing the lower portion of the damper inwardly and the outer portion thereof inwardly, as shown in Figure 1. In order to restore the static balance of the damper disturbed by the offset or eccentric pivoting thereof, a symmetrically distributed enlargement or weighted portion 10 is provided along the upper edge thereof.

For the purpose of biasing the damper to closed position, in which position its lower edge engages a stop lug 11, an adjustable weight 12 is provided and is fixed to and supported upon the inner end ofa screw 13-adjustably fitted in a bearing provided on the damper 7 and disposed with its axis intersecting the axis of swing of the damper and in a plane at right angles to the plane of the damper and passing through its axis. A nut 14 is threaded on the screw 13 and is held against axial movement and releasably secured in any angular adjustment by a flat spring 15 fastened to the damper and bearing on the nut. The end of the spring 15 also constrains the screw 13 to axial movement in that it engages a fiat 13' provided on the screw. The weight 12 may be adjusted to maintain the damper 7 closed until the draft through the stack exceeds a predetermined value.

In many instances, however, it is desirable to have the combustion in the boiler or furnace accelerated even after the draft in the medium or the desired rise in the room temperature. Frequently rapid or accelerated combustion must be sustained over a considerable period to bring the temperature of the heating mediumor the room temperature up to the desired point.

V In order to provide for sustained acceleration of combustion and yet prevent combustion from progressing or continuing beyond the point where the heat generated can be absorbed with safety and efliciency in the system, the check draft damper 7 may be further regulated in its action by means of an auxiliary control. \Vhile this auxiliary control may take several forms only one type is illustrated, and, as shown, comprises an electromagnet 20 supported in a casing 21 fixed to one of the end walls of the damper casing 6. The excitation of the windings of the magnet 20 is controlled by an ordinary room thermostat 22, the terminals. of the windings 20 of the magnet being connected in circuit with the thermostatic switch of the room thermostat, as illustrated in Figure 3 or in any appropriate manner. An armature 22 of laminated iron is secured between carrier plates 23 of insulating material by means of bolts and nuts 24. The plates 23 are pivotally or rockably supported on a supporting pin 25 extending loosely through openings in the plates and secured to the back wall of the casing 21. The armature 22 is curved slightly so that in one position its ends lie in close proximity to the pole pieces 20' of the electromagnet. A yieldable arm 26 which may be of fiat resilient metal has one end secured to a screw or bolt 27 extending between and fastened to the plates 21 at one corner of the carrier and has its other end weighted as indicated at 28. The weight 28 and the weight of the arm'26 biases the armature 22 to the position shown in Figure 3 wherein its ends are moved a slight distance away from the pole pieces of the magnet.

As shown in the drawing the arm 26 extends through a slot in the casing 21 and projects into adjacent proximity to the damper 7. A pin or projection 29 is secured to the damper 7 along the line of its axis of rotation and has an offset outer end 29' adapted to be engaged by the yieldable arm 26 when the yieldable arm is rotated or shifted up to the position shown in dotted lines in Figure 3. It is obvious that the plates 23 in their connecting parts constitute a shiftable sup-g port orshiftable carrier for the biasing-arm 26 and that shifting of the support controls the coaction of the biasing arm with the damper. Excitation of the magnet will attract the ends of the armature 22 into close proximity to the pole pieces and in so doing will rock the armature and its carrier and consequently rock the arm 26. When the will complete the electrical circuit in which room thermostat calls for heat its contacts 3 tioning the arm in engagement with the projection 29. When the arm 26 engages the projection 29 it tends to'hold the check draft damper 7 closed and any opening of the. damper at such times is against not only the action of its biasing weight 12 but. also against the yieldable resistance afforded by the arm as to be liable to accelerate combustion beyond the point where the heat eneratedcan be absorbed with safety and e ciency'in the system the increased suction on the damper 7 will cause it to swing inwardly, the arm 26 flexing under-the pressure of the projection 29 to permit of the opening of the damper 7. This maintains the amount of air pulled through the fire at the desired value. When the temperatureof the room rises to the selected point the room thermostat breaks the circuit in which the electromagnet islin corporated and the arm 26 drops down to the position shown in Figure 1 in which position the draft must overcome 'merely the force of the biasing weight 12 to effect opening of the check draft damper. Reference is made to my copending' a plication for Heater controls (Case A Serial No. 371,074, filed under even date herewith for a full disclosure of the details of construction of this electromagnetically controlled auxilregulator 36.

iary biasing means. I

, A direct draft opening 30 is provided in the ash pit of the furnace and is controlled by a direct draft damper 31 having a weighted arm 32 fixed to its axis of rotation and connected by a chain 33 to a lever 34 d fulcrume d as at 35 on a regulator casing 36. Adjustable weights 37 and 38 may be provided on the lever 34. Just beyond this fulcrum the lever 34 is operatively connected as at 39 to the dia hragm (not shown) of the e regulator 36 may be of any conventional construction and as these regulators are widely known and used no detailed disclosure thereof is deemed necessary.

Where a banked or slow fire is to be maintained it is advantageous to have a positively and automatically controlled direct draft damper in combination with the balanced and .variably biased check draft damper for, with a slow burning fire, the draft through the stack is at times, ver slight and it is desirable to accelerate the raft by positively o ning the direct draft damper when more hzat is desired and-combustion is to be increased. When the" temperature or pressure of the heating medium rises to the point for which damper casing having its ends 0 n and having one end communicating w th the stack for the heater and the other end communicating with the atmosphere, a balanced damper supported on said casing for free movement under the influence of a draft, an adjustable bias for the damper operating to prevent movement thereof until the draft has reached a predetermined value, a direct draft 26. In the event that the draft so increases check draft damper freely supported so that the draft through the stack tends to open the same, an adjustable overbalance mounted on the damper and tending to close the same while permitting the damper to open when the draft in the stack exceeds a predetermined maximum, room'thermostat controlled means for applying an additional yieldable bias to the check draft damper, a direct draft damper, and means responsive to conditions in the heater for positively controlling the opening and closing of the direct draft damper. 3 A control for heaters comprising acheck draft damper freely supported so that the draft through the stack tends to open the same, variable biasing means for urging the check draft damper to closed position, room thermostat controlled means for varying the action of the biasing means, a direct draft damper, and means responsive to conditions the heater for positively controlling the opening and closing. of the direct draft am r.

In witness whereof, I hereto aflix my sig nature.

' GALEN D. BARKER.

the regulator 36 is set the lever 34 is v a counter-clockwise direction as viewe Figure 1 to ermit the damper 30 to close under the i uence of its weight 32.

The invention claimedis: 1. A control for heaters comprising a

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