US1493552A - Damper regulator - Google Patents

Description

May 13 1924.

J. L. KIMBALL DAMPER REGULATOR Filed Jan. 8. 1923 2 Sheets-Sheet l Fig.1

INVENTOIE May :13, 192%, 93552 J. L. KEMBALL DAMPER REGULATOR Filed Jan. 8. 1923 2 Sheets-Sheet 2 Patented May l3, i924.

JAMES LEWIS KIMBALL, OF SALEM, MASSACHUSETTS, ASSIGNOR TO R'UGGLES-.KLINGE- NN MFG. (10., F SALEM, MASSACHUSETTS, A CORPORATION OF-MASSACHUSETTS DAMPER REGULATOR.

Application filed January s, 1923. seriaino. $11,390.

T 0 all whom it may concern:

Be it known that 1, JAMES Lew s KIM- BALL, a citizen of the United States, residing at 9 Dearborn St, Salem, in the county of Essex and State of Massachusetts, have invented certain new and useful Improvements in Damper Regulators, of which the following is a specification.

This invention relates to damper regulators for controlling the air supply to boiler furnaces from variations of steam pressure generated by said boilers, and particularly to improved means for variably compensating the movement of such regulators from the flue gas pressure.

My invention is a furtherdevelopment of the present art as in this invention I substitute flue gas pressure for mechanical means for variabl compensating the action of a regulator which is controlled primarily from steam pressure. 4 I

The object of this invention is to automatically correct a condition of furnace inefliciency due to the volume of gases -generated in the boiler furnace not being consistent'with the load on the boiler as indicated by the steam pressure, and to provide means whereby the variation in flue gas pressure may reverse or nullify the action of the damper regulator as controlled from thesteam pressure, but to provide certain limits in pressure under which the control of the damper will be placed under the control of the steam pressure regardless of the furnace conditions, or the volume of gases being discharged to the stack or chimney. It will be understood that where mechanical means is provided for variably governing the movement of the flue damper, thecompen sating elfect will not always be applied at the proper pointto check the draft, under light load conditions or when only a few of the total number of boilers are in use the damper is to be closed to a greater extentv before a grip is obtained on the draft than what would be the case when the load was eavy and all the boilers were in use.

In my invention an increase in steam pres-- bed, and from the point where the regulator commences to check the draft to a closed damper position, an increasingly counteracting force'is applied to the regulator. From its working position where it commences to check the draft any increase or decrease in the volume of gases generated will move 'the damper, and increase in gases slightly in the second case we avoid an excess of air passing through the furnace with corresponding losses due to excess heat in the flue gases.

A clear conception of my invention may be had by reference to the drawings accompanying and forming a part of the specifications, in which like reference characters designate the same or similar parts in the several views.

Fig. 1 shows the application of my invention to a main flue damper of two steam boilers. Fig. 2 shows a vertical section of my invention in which the weight levers of the steam pressure chamber andthe flue gas pressure. chamber are connected together. Fig. 3 represents an embodiment of my invention in which the weight leverso'f both the steam pressure chamber and flue gas pressure chamber operate directly on the controlling valve.

Referring to Fig. 1. The steam boilers are represented'by (1),and (2). (3) is the main flue, (4) the stack of chimney, (5) is the steam discharge pipe from the boilers. (6) is the main flue damper, (7) is a fluid pressure motor for operating the damper, the action being that: when fluid pressure is admitted to-the bottom of the motor, it raises weights (8) and allows weight (9) to close damper, and when fluid pressure is exhausted from motor (7), it allows weights (8) to become effective, and overcome weight (9) and open damper. (10) is a fine gas connection to pressure chamber (11), (12) is a steam pressure connection to pressure chamber (13). Pres-.

pressure to fluid pressure motor (7).

sure chambers (13) and (11) are closed by flexible diaphragms (14) and (15), weight. lever (16 is fulcrumed at (17), a pressure cap (18) is in contact with the atmospheric side of diaphragm (14) and en-' gages weight lever (16) at point (19). The steam pressure in chamber (13) is counteracted by wei hts (20) placed'on weight lever (16). ariation in pressure in chamber (13) operates controlling valve (21) throu h connection (22) controlling valve (21) as inlet for fluid pressure at (23), delivering to fluid pressure motor at (24) and exhaust at (25). The negative gas pressure acting in chamber (11) is counteracted by weights (26), the weight lever (27) being fulcrume'd at (28 a connection (29) being made between the left hand end of scale beam (27)-and arm (30) which is fulcrumed to weight lever (16) at point (22).

The right hand end of arm (30 is con-' nected with operating valve yoke (31) which controls the admission and exhaust of fluilgl clearer conception of the operation of this valve will be had by referring to Figs. 2 and 3. It will be seen that the yoke (31) is connected to valve stem (32), valve stem (32) having cylindrical portions (33) which controls the admission and exhaust of fluid pressure to motor (7), when the stem is raised the pressure from connection (23) is admitted to connection (24), and when the stem is lowered, this pressure is closed ofl and the pressure in connection (24) is discharged through exhaust connection (25). The two pressure devices that, are acted upon by the pressure, are each balanced by counteracting weights placed on the weight levers, and each act independently of one another, to operate the controlling valve to actuate the fluid pressure motor to open and close the main damper.

We will now explain the operation of the regulator from steam pressure. An increase in steam ressure is communicated through pipe (12) to diaphragm chamber .(13) which forces pressure cap (18) downward and as weight lever (16) is fulcrumcd at (17) point (22) to which arm (30) is pivoted will be raised and as the left hand end of arm (30) for the time being is held stationary by connection (29). it will be apparent that the right hand end of arm (30) will be raised with scale beam (16), and as yoke (31) is connected to the right hand end of arm (30) and the upper end of the yoke connected to valve stem (32), it will be seen that the controlling valve will admit fluid pressure to the motor cylinder (7) and force piston (34) upward closing the damper and as the boiler pressure is reduced the. balancing weights (20) will overcome the pressure in chamber (13) masses andweight lever (16) will be moved down ward closing the admission of pressure to the operating cylinder and opening the same to exhaust, causing piston (34) to be forced downward by weight (8) and opening the damper. I

The operation thus far explained would be of the non-floating form, the damper would be opened and closed with only slight variation in steam pressure. We will now explain the operation from flue gas pressure and show how the regulator operated from steam pressure is compensated and becomes a variable floating device from the action of the flue gas pressure. The gas pressure in the main flue is usually negative to the amount of the chimney action, but may be increased to zeroor even become positive at times. The variation in pressure being due to the volume of gases being generated in the boiler furnace or to the position of the main damper. Assuming a fresh charge of coal to be placed in the furnace, the increased volume of gases will reduce the ne ative pressure and this reduction of negatlve pressure actin in chamber (11) will allow weights (26 to overcome the atmospheric pressure as exerted on the top of diaphragm (15) and diaphragm (15) will be raised, this movement of the diaphragm acting through connection (28) and arm (30) will give a downward movement to yoke (31) and valve stem '(32) which will exhaust fluid pressure from cylinder (7) and slightly open damper. The reason why damper is not opened wide is that as the damper Sttll'tS to open, the negative pressure in the boiler fine is increased by the chimmcy action and this change in pressure acting through pipe (10) allows the atmospheric pressure to overcome weights (26) and the controlling valve is at once/moved from an exhaust position to a neutral position. Assuming that the fuel in the boiler furnace has burned down so that the volume of escaping gases is materially lessened then the suction in the main flue is increased by increased chimncycaction, and this increased vacuum or negative pressure acting in chamber (11) will allow the atmospheric pressure to force diaphragm (15) downward which will operate motor piston (34) on the upward stroke slightly closing damper. which closing reduces the negative pressure and checks the further closing of the damper. From the above it will be seen that the fluid pressure motor can be operated indepen dentally from either variations in flue gas pressure or from variations in steam pressure.

)Ve' will now explain the compensating effect, the flue gas has on the regulator when operated from steam pressure. On an increase in steam pressure the damper is closed toa position where it commences to check the draft, and as the closing of. the damper commences to reduce the negative pressure in the boiler flue, the change in pressure is communicated to diaphragm chamber (11) which allows weights (26) to overcome the pressure of the atmosphere moving the diaphragm upward and controlling valve stem downward which move-.

ment is in the opposite direction to what the valve is being moved by. the steam pressure. The further the steam pressure closes the damper the less the negative pressure becomes and the more the gas regulator tries to open it. This conflict is continued for a certain range in pressure then the steam pressure device overcomes the gas device and the motor is moved to close the damper and prevent a further rise in pressure. On a decrease in steam pressure, the steam device will operate the controlling valve to open damper and the increase in negative pressure due to the opening of the damper will act to return the controlling valve to a neutral position checking the further opening until a further drop in steam pressure takes place. This conflict of pressure devices is continued until the damper is opened to a position where maximum draft is obtained and from this point to a wide open position the damper is freely moved without compensating eflect.

Referring to Fig. 2. we show a slight modification from what is shown in Fig. 3. While Fig. 3 shows an arrangement whereby the controlling valve is operated from either variations in flue gas pressure or variations in steam pressure, the ar-'- rangement in Fig. 2 permits variation in flue gas pressure to counteract the operation of the controlling valve as operated from steam pressure, the effect in both cases is the same.

In' the ordinary draft regulator with mechanical means for compensating its movement, theregulator will commence to compensate in closing: off the draft from its first movement, andwill compensate the same for light loads as for heavy loads, but with my invention no compensating action takes place until the damper reaches a position where it commences'to get-a grip on the draft. The benefit of such a device is that it at once on a change of pressure swings the damper to a posltion where it commences to regulate the draft, and the two extremes of excess air on one hand and insufficient air on the other is avoided, and this permits me to operate boilers at low ratings nearly as efficient as at maximum efficiency ratings. It also permits me to operate boilers at a much smaller pressure operating range between, minlmum and maximum 'air sup ly than what was formerly required. Wit my invention the draft regulator becomes self compensating and compensates at the point where'incre'mental action is required,fand willnot compensate at the other points where no compensating action is required.

In case of a single boiler when the load is light and the fuel bed is thin, the same amount of damper opening for agiven drop changed from flue gas pressure to correction variation in load or furnace conditions, where such variations have not affected the steam pressure.

I am well aware of the fact that others have devised means for limiting the action of a flue gas or furnace pressure regulator from the steam pressure of the boiler, but in such regulators (and I refer to Parker #575,849 of January 26, 1897, and T. Niell #526,510 of September 25, 1894) the damper is controlled primarily from flue gas or furnace pressure and the steam pressure device is used to block or limit the movement of the gas regulator In my invention the damper is moved primarily from steam pressure and the flue gas is used to variably compensate its action in accordance with the'rate of combustion.

It will be understood by those skilled in the art that I have devised novel and satisfactory means for correcting defects in damper regulation, when such regulation is effected solely from steam pressure, and it is to be understood that the various instrumentalit-ies of which my invention consists can be variousl arranged and organized without departing from the scope of the invention. I therefore, desire only. such limitations as are set forth in the appending claims.

I claim: p

1. In combination with a plurality of steam. boilers, a main draft flue for said boilers. a damper in said fine, a chimney or stack for creating a draft in the flue for discharging the gases generated in .the' furnaces of said boilers, means for operating said damper from variations in steam pressur'e generated by said boilers, and means for compensating the movement of said damper operating means from variations in draft caused by the movement of the damper from variations in steam pressure.

2. In combination with a flue damper for controlling the discharge of gases generated in the furnace of a steam boiler, a motor for controlling the damper, a valve for eon trolling the motor, means for controlling the valve, comprising two pressure motors, one of said motors being actuated by variations in steam pressure discharged by said boiler, and the other motor being actuated by variations in gas pressure discharged by said furnace.

3.1n a regulator for controlling comhustion in a boiler furnace comprising a motor for regulating the discharge of gases from said furnace from steam pressure generated by said boiler, means for varying the movement of said motor from variations in the rate of combustion independent of the steam actuating means. and means for compensating ,the movement of said motor from variations in flue gas pressure caused by the movement of said motor.

4. In combination with a fine damper for controlling the discharge of gases from a boiler furnace, a motor for primarily actuating said damper from variations in steam pressure generated by said boilers means to vary the movement of said motor from 'ariations in the rate of combustion independent of the steam actuating means. and means forcompensating the movement of said motor from variations in flue gas pressuren'hen said damper is movedt'rom variations in steam pressure.

JAMES LEWIS KIMBA IL.

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