US1338898A - Regulating combustion in furnaces - Google Patents

Description

F. H. BROWN.

REGULATING COMBUSTION IN FURNACES.

APPLICATION FILED Dsc. lo, 1917.

WITNESSES INVENTOR UNITED sTATEs PATENT OFFICE.

FRANCIS H. BROWN, 0F PHILADELPHIA, PENNSYLVANIA, ASSIGNOB TO JOHN M. y

HOPWOOD, 0F PITTSBURGH, `PENNSYLVANIA. y

REGULATING COMBUSTION IN FURNACES.

Specification of Letters Patent.

Patented May 4, 1920.

To all whom t may concern:

Be it known that I, FRANCIS H. BROWN, residing at Philadelphia, in thev county of Philadelphia and State of Pennsylvania, av

citizen of the United States, have invented or discovered certain new and useful Improvements in Regulating Combustion in Furnaces, (Case C,) of which improvement the following is a specilication. v

The invention described herein has for its object the maintenance of any desired substantially constant or uniform pressure ink a furnace or lire box of a boiler, regardless of the rate of combustion of the fuel in the re box. In general terms, the primary step or operation of the invention consists 1n regulating the flow of air to the fire box by and in accordance with the rateof flow of steam through the outlet pipe of the boiler to the engine or other point of use and controlling the escape ofgases or products of combustion from the 'lire box, and the rate of feed of fuel to the fire box by and in accordance with the pressure of the gases in the latter. The invention is hereinafter more fully described and claimed.

In the practice of the invention, sultable means operative by the ydifference in `pressure between the static pressure of steam flowing along the pipe 2 leading from the boiler 1 and such pressure as effected, posltively or negatively, by the velocity of flow of steam through such pipe, are employed as the V rimary agent in controlling operations a ecting the generation of steam. convenient means for utilizing such differences of pressure consists of a Pitot tube 3, or other equivalent means known in the art, arranged in the steam pipe 2 and having its nozzles connected by plpes 4 and 5 to opposite sides of the shell of a diaphragm motor 6, the point of connection of the pipes with the shell being on opposite sides of the diaphragm. While any suitable form or construction of pressure actuated motor, combined with suitable appliances whereby the motion of the movable element of the motor may be em loyed for controlling the How of air to the re box or combustion chamber, it-

is preferred to use the construction of apparatus shown and described in application Serial Number 184,260 filed August 3rd,

1917. As therein shown and described, the

diaphragm is connected to a lever 7 which has its free end connected by a turn buckle 8 to a pivotally mounted'frame 9. On this frame is pivotally mounted a bell crank lef ver 10 having one arm connected to a valve mechanism 11 adapted to control the flow of fluid ressure to opposite ends of a c linder 12. he other arm of the bell cran lever 10 is connected by a rod 13 to a pivotally mounted standard 14, having connected thereto a shoe adapted to engage an adjustable angularly arranged rod 15. This rod is. carried by a frame 16 secured to a bar 17, which is connected to the piston 18 of the cylinder 12 by an arm 19. As it will ben readily understood, a movement of the diaphragm of the motor will shift the frame 9 and operating through the bell crank 1ever 10 will so shift the valve mechanism 11 as to admit fluid pressure to one or the other end of `the cylinder 12. The movement of the piston of this cylinder by such admitted iuid pressure, will raise or lower the angularly arranged rod 15 and the latter operating through the shoe carried bythe standard 14 ywill shift the latter and such movement of the standard will so shift the bell crank lever 10 as to check further flow of` fluid pressure through the valve mechanism to the cylinder 12. By reason of the employment of this compensating mechanism, the movement of the piston is not total but only incremental and will correspond t0 the movement imparted to the diaphragm of the motor 6 by variations in the velocity of flow in the pipe 2.

Any suitable means may be employed for connecting the rod 18 with means controlling the 'flow of air under pressure through the conduit 20 tothe ashpit of the fire chamber or box 21. As will be readily understood by those skilled in the art, there are a variety of means for controlling the flow of fluid under pressure and while any of these well known devices and means may be employed, one of the simplest forms of apparatus is shown herein for that purpose and consists of the employment of a fan mechanism 22 operated at a constant speed to maintain a supply of air constant as regards pressure regardless of the rate of flow anterior to the damper 22 in the conduit 20, controlling the How of the air under pressure to the fire box. A convenient means for shifting this vdamper by the piston of tached to the around guide ulleys 24 and suitably atrum 25 on the shaft of the damper 22. By properly adjusting the connections to the drum 25 any desirable movement of the damper can be obtained from a given movement of the piston of the cylinder 12. In case of any change in the rate of flow of steam through the pipe 2, a corresponding change will, through the operation of the mechanism described, shift the damper 22 correspondingly, that is to say, if the rate of flow of steam through the pipe 2 is increased, the damper 22 will be shifted in crementally toward open position, but if the rate of flow of steam is decreased, the damper will be similarly shifted toward a closed position.

In order that changes in the rate of flow of air under pressure to the re box may not materially affect or change the pressure of gases desired in the fire box 21, provision is made for changing the position of the damper 26 in the gas outlet pipe 27, in such direction and to such extent as to maintain the pressure substantially uniform in the fire box.

While any suitable form or construction dated November 20th, 1917, and diagrammatically shown herein. Generally stated,

.the fire box 21 is connected by a conduit 27 to the interior of a tank arranged in an inverted position Within a body of liquid, so that said tank will rise and fall with changes of pressure in the fire box. This tank is connected as shown in said patent, to the Valve mechanism controlling the flow of fluid pressure through opposite ends of a Huid pressure cylinder 28. The' piston rod 29 of said cylinder has its upper end connected by a cord 30 to thedrum 31 on the shaft of the damper 26, and has attached thereto a suitable counterbalance so thatthe downward movement of the piston rod will shift said damper to open position, the reverse movement being preferably effected by a weight 32. It will be understood that the dampers 22 and 26 will be so shifted that a tendency to an increase of pressure in the fire box due to opening of the damper22 will be at once counterbalanced and corrected by a sufficient opening of the damper 26 in the conduit 27. l

Any changes or variations in the rate of oW of steam through the pipe 2 and consequent changes of supply of air under pressure should be accompanied by` a corresponding change in the rate of feed of fuel to the fire box so as to maintain the proper relation in the supply of fuel and air for combustion for all variations in the rate of combustion or load on the furnace. Such adjustment ofthe rate of feed of fuel is preferably controlled by and in accordance with changes of pressure in the fire box 21. This adjustment of the feed of fuel can be conveniently effected by connecting the lower end of the piston rod 29 of the pressure actuated device -by a lever 33 to the valve rod 34 of the valve mechanism 35 which is adapted to control the flow of steam lthrough the pipes 36 and 37 to the motor of the fuel feeding mechanism indicated at 38. In addition to changing the rate of feed of fuel and air for combustion in accordance with changes of rate of flow of steam through the pipe 2, provision is made for regulating the flow of feed Water to the boiler which is also controlled by and in accordance with changes of pressure in the fire box. A convenient means to this end consists in connecting a piston rod 29 by a cord 39 to an arm 40 y of the valve 41 controlling the flow of Water through the feed pipe 42.

It is characteristic of the invention described herein that difl'erences of pressure Idue to differences in rates of flow of steam sure to the fire box and consequently the rate of combustion in the fire box d ue to such changes in the rate of flow of air thereto. are utilized for controlling other opertions, z'. e., the feed of fuel and the feed Water to the boiler or generator.

I claim herein as my invention:

1. The method herein described which consists in regulating the flow of air under pressure'to the fire box of a boiler by and in accordance with the rate of flow of steam from the boiler-to a point of use and rebulating the flow of products of combustion from the fire box by and in accordance with the pressure of gases in the fire box.

2. The method herein described which consists in regulating the loW of air to the fire box of a boiler by and in accordance With the rate of flow of steam from the boiler to a point of use, and regulating the feed of fuel to the fire box by and in accordlance with the pressure of gases in the fire consists in regulating the flow of air to the fire box of a boiler by and in accordance with theflow of steam from the boiler and regulating the feed of Water to the boiler by and in accordance With the pressure of gases in the furnace.

4. The method herein described which consists in regulating the flow of air tothe fire box of a boi-ler by and in accordance with the flow of steam from-the boiler and regulating the discharge of gases from the 3. The method herein described which re box by. and in accordance with thepressure of gases in the fire-box.

5. The methodherein described which consists in regulating the How of air to the fire box of a boiler by and in accordance with the flow of steam from the boiler and regulating the discharge of gases from the gases in the fire-box.

In testimony whereof, I have hereunto set lny hand.

FRANCIS H. BROWN.

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