US1338922A - Regulating combustion-furnaces - Google Patents

Description

1-, M. HOPWOOD. REGULATING COMBUSTION FURNACES.

APPLICAHON FILED JUNE Ii, I9l7.

Patented May 4, 1920.

3 SHEETS-SHEET! INVENTOH W g m R8 MW 6 MM' J. M. HOPWOOD.

REGULATlNG COMBUSTION FURNACES.

APPLICATION FILED Hm: H. 1917.

3 5HEETSSHEET 2. Q r n WITNESSES INVENTOR 11M: HOPWOOD.

REGULATING COMBUSTION FURNACES.

APPLICATION FILED JUNE 11, 19!? 1,838,922. n e May 4, 1920.

,3 SHEETS'-SHEET 3- JOHN M. HOPWOOD, 0F PITTSBURGH, PENNSYLVANIA.

v REGULATING COMBUSTION-FURNACES.

Specification of Letters Patent. I

Patented May 4, 1920.

Application filed June 11, 1917. Serial No. 174,039.

T 0 all whom it may concern:

Be it known that 1, JOHN M. Horwoon, residing at Pittsburgh, in the county of Allegheny and State of Pennsylvania, a citizen of the United States, have invented or discovered certain new and useful Improves ments in Regulating Combustion-Furnaces, of which improvement the following is a specification.

l't'has heretofore been the practice to regulate the rate of combustion in furnaces for boilers, etc, by and in accordance with the pressure of the steam in the boilers or gases in the combustion chamber, or both. These methods are lacking in efficiency for the Ma son that the pressure in the boiler does, to a considerable extent, depend upon the rate of use of the steam in engines and other motors, and hence in any system depending upon pressure, the operation of the regulating devices is due to what might be termed a secondary effect and not to a primary, 2'. e., the supply of steam or fluid which in itself produces this secondary effect. The pressure method of regulation is also inefficient as it is possible in the operation of a plurality of steam generators as a unit, that a number of the members of the unit will operate at full capacity and. supply sufficient steam at high pressure to maintain the desired pressure of steam in a boiler operating inefficiently, and the feed of fuel, etc, to such generator will not be suflicient to bring its effectiveness up to the desired point.

' The invention described herein relates to the regfiilation of the supply offucl and air for the combustion of the fuel by and in accordance with the rate of use of the steam.

-and by and in accordance with the flow of steam from the boiler and the pressure of steam in the boiler The invention is hereinafter more fully described and claimed.

In the accompanying drawings forming a part of this specification, Figure 1 is a diagrammatic view illustrating a boiler and its.

settings and having applied thereto apparatus and mechanical devices for the practice of the invention; Fig. 2 is a similar view illustratinga modified arrangement of the mechanism; Fig. 3 is a sectional view on a large scale of a form of differential mechanism operated by differences between the static pressure and the total pressure of. steam flowing along the steam'supplypipe and adapted to operate other devices or\ apparatus for controlling the feed of fuel and the forced draft; Fig. 4.- is a sectional view on an enlarged scale of the valve mechanism shown in Fig. 3; Fig. 5 is a detail view showing a portion of the compensating mechanism shown in Fig. 3; Fig. 6 is a sectional View of a balanced valve usable for controlling operations of stoking mechanism; Fig.

7 is a sectional View on an enlarged scale of a form of Pitot tube employed in the practice of the invention; Fig. 8 is a. sectional View of a device which can be used in lieu of the Pitot tube; Figs. 9 and 10 are dia igrammatic views showing the adaptability of the invention for controlling combustion when liquid or gaseous fuel is employed; and Fig. 11 is a detail. view of a modified form of mechanism for controlling the feed of fuel to the furnace.

In practice the improvements are applied to any form or type or construction of furnace for boilers and other purposes. Any suitable type of stoking mechanism indicated at 1 may be employed for feeding fuel into the. fire chamber 2, and the ash-pit 3 has connected thereto one end of an air conduit 4 extending from a blower 5 operative by any suitable form of motor such as the steam motor 6 as shown in Fig. 1. In the form of apparatus shown in Fig. 1,thc fuel is forced in upon the grates by a plunger 7, operated through suitable mechanism by the steam cylinder 8 which is connected through a balanced regulating valve-mechanism 9 of any suitable construction, to the boiler. A suitable construction of regulating valve is shown in Fig. 6. 1n the pipe 10 extending from the boiler to the engine -11 or other user of steam, is arranged what is known as the Pitot tube 12. the respective passages in such tube' being connected by pipes 13 and 14- to opposite sides of a shell 1:) across which is arranged a diaphragm 16 clearly shown in Fig. 3. This diaphragm motor may be of any suitable construction. The diaphragm 16 of this motor will be shifted in one or t 1e other direction in acco rd a ncc with var 1a t1 ons o f pressure due to changes in the rate of flow through the pipe 10, z. c the amount of steam used in the engine or otherwise. This diaphragm 16 is adjustably connected by an arm 17 to a pivotally mounted frame 18 as shown in Fig. 3. On the frame 18 is pivotally mounted a bell crank lever 19 having one end connected tothe, rod of the piston valve '20 arranged in the valve casing 21. The opposite end of this bell crank lever is connected by a rod 22 to a pin 23 on the pivotally mounted standard 24, as clearly shown in Fig. 3. I A. shoe 25 is pivotally mounted in the upper end of the rod 24- and is adapted to be engaged by and permit of the movement of an angle rod 26, which is so mounted on the frame 27 as to permit of its angular adjustment. The

. frame 27 is secured to a rod 28 having its upper end connected by an arm 29 to the piston rod-30 of a fluid pressure cylinder 31. In the operative mechanism just described, the movement of the diaphragm will shift the piston. valve 20 in the shell 21 so as to admit fluid pressure to one or the other of the pipes 82 or 33, connected respectively to the upper and lower ends of the cylinder 31 and thereby causing a movement of the piston 3-1 in said cylinder.

As the piston moves up or down, the angle rod 26 will also be shifted and by reason of itsinclination as indicated in Fig. 3 will rock the standard 24;, and by reason of the engagement of'this standard through the rod 22 with the bell crank lever 19, will shift the valve 20 in the opposite direction to that imparted to it by the movement of the frame 18, thereby cutting off any further flow of fluid under pressure to the cylinder 31. i

As clearly shownv in Fig. 4, the valve mechanismcontrolled, as above described, consists in an outer shell 21 within which is arranged a sleeve having rings forming a steam tight fit with inner wall of the shell 21 forming annular spaces for the flow of steam as hereinbefore described. The steam enters by the port through the pipe 36 to an annular space 37 and thence through port 38- into the interior of the shell and escapes in the shown position of the valve through the port 39 into the annular space to which the pipe 32 is conneeted. At the same time, the steam will flow from the lower end of the cylinder- 31 into the annulaspace 40 of the valve,

' thence by the port 41 to the interior of the sleeve whence it will escape from the valve casing. The position of the alve shown in Fig. 4: is effected by the movement of the valve imparted thereto by the diaphragm, but as soon as the piston 34 is shifted downwardly a distance predetermined by the angle rod 26, the lever 19 will be so shifted as to move the valve 20 down, closing the port 30 and thereby preventing the further movement of the piston 34.

To the piston 34- is connected, as before stated, a rod 30 and an oppositely arranged rod 30. A rope 50 or ether flexible means which is connected to '10 of the rods as 30*,

rod 53 projecting from the opposite end of the valve mechanism 9 is connected to a rope M which passes around guide pulleys 55, one or more times around a drum 56,

around a guide pulley "-7, one or more times around a drum 58, around a guide pulley 59 to the rod 30. The drum 56 is connected to the shaft of a damper-6O arranged in the air conduit 4 leading to the ash-pit, while the drum- 58 is secured to the shaft of a damper 61 arranged in the stack of the boiler.

It will be readily understood that upon a variation of the pressures exerted on opposite sides of the diaphragm 16, due to changes in the rate of flow of steam through the pipe 10, the piston in the cylinder 31 will be shifted and in accordance with such movement, will shift the piston of the valve in the mechanism 9 so as to vary the rate of feed of fuel on to the grate bars and will also change the position of the damper 60 in the air blast conduit 4:, so as to shift more or lessair into the under side of the grate. When a damper isemployed in a stack as described, it will also be shifted at the same time With the changes of the mechanism for feeding fuel and controlling the air blast so in accordance with the changes in the rate of flow or. use of the steam, the quantity of steam required under normal conditions being known, as also the quantity of coal necessary to be burned to produce such quantity of steam and the volume of air required for effecting such combustion of the fuel. Supposing for example it requires one thousand-(l000)-pounds of steam in a predetermined time to normally operate the engine 11 the amount of coal which must be fed on to the grate bars and con sumed in order to effect the generation of such quantity of steam in a given time can be readily determined as also the quantity of air required for such combustion. Having determined these factors, the setting of the apparatus to operate under normal conditions can be readily effected and any change with the quantity of steam passing through the outlet pipe 10.

As will be readily understood by those skilled in the art, the fluid pressure motor employed for feeding fuel as shown in Fig. 1, may be replaced by 'an electric motor 67, as shown in Fig. 2. In such case a rheostat 68 will be substituted for the regulating valve mechanism 9, shown in Fig. l and the controller armtli) of the rheostat will be connected to the motor 31.

If desired, this chain grate of the stoking mechanism may hefpperated step by step, as shown in Fig. 11: by securing a ratchet wheel 7% to one of the shafts of the stoking mechanism. This ratchet wheel is shifted by the oscillations of the lever 71, carrying the pawl 72 adapted to engage the ratchet wheel. The lever is reciprocated by a constantly rotating shaft 43 through suitable mechanism, such. as an eccentric mounted on I the shaft and having its strap connected by a pitlnan 44 to a sleeve 45 slidable along the lever. The position of the sleeve on the lever and consequently the movement of the grate, is controlled by the motor 31.

It is characteristic of the methods and mechanisms heretofore employed for combustion, that regulation was effected by or in accordance with variations in what has been termed herein, secondary or resulting effects, 2'. 6., pressure in the boiler, pressure in the combustion chamber and the flow of products of combustion or by or in accordance with combinations of such secondary effects; but the main characteristic of the invention described herein is the regulation of the fuel supply and the supply of air to effect combustion by-and in accordance with the quantity of steam drawn from the boiler and entirely independent of any variations of pressure in the boiler resulting fr om the flow of steam to the point of use.

In the form of apparatus shown in Fig. 1, the fan is operated to give a constant volume of air in a given period of time, the operation of the engine being controlled by a Mason or other type of regulating mechanism 62. It may at times happen that the adjustment of the mechanism hereinbefore described may not be such as to maintain the desired supply of steam and consequently the pressure in the boiler may drop even with the fuel and air feed open to the widest extent to which they have been adj usted. In such contingency, the Mason regulator as it is operative in accordance with. changes of pressure in the boiler and controls the operation of, the fan will permit of an increased operation of the fan. In order to effect an increased feed of coal under such abnormal conditons. provision is made for increasing the rate of fuel feed.

. A convenient means to this end consists in trolling the fan engine by a rope (36 to thepressure reducing valve so that when the Mason regulator operates, to permit of the operation of the fan at a higher speed, the reducing valve 433 will be correspondingly adjusted so as to permit a. higher pressure to flow to the stoking mechanism and thcrcl'iy increase the feed of fuel. ()n the return of the hlason regu lator to conditions to which it had been set for normal operation, the reducing valve may be returned to normal position by a weight or other suitable means.

In lieu of the litot tube, shown in Figs.

1 and 7, a disk 66 with an orifice less than the diameter of the pipe 10 may be arranged therein and the pipes 13 and 14 connected to the pipe 10 on opposite sides of this disk, as clearly shown in Fig. 8.

As shown in Figs. 9 and 10, the invention described herein may be applied for controlling the flow of liquid or gaseous fuel to a burner (37 and also .he flow of air necessary for supporting the combustion of such gaseous or liquid fuel.

I claim herein as my invention:

1. The method herein described of controlling combustion in furnaces which consists in regulating the supply of fuel in accordance with the flow of steam from the boiler and varying the feed of said fuel in accordance with variations in the static pressure of the steam.

2. The method. herein described of controlling combustion in furnaces, which consists in regulating the feed of fuel and the flow of air to support combustionin accordancef'with the flow of steam from the boiler and varying the supply of air in accordance with variations in the static pressure of the steam.

3. The method herein described of controlling combustion in the furnace of a boiler which consists in forcing air into the fuel and simultaneously regulating such feed of air and the discharge of gases from the furnace in accordance with the flow of steam from the boiler.

4. The method herein described of controlling combustion in furnaces which consists in normally regulating the supply of fuel and air to the combustion chamber in accordance with the rate of flow of steam from the boiler, and varying the supply of fuel and air in accordance with the variations of pressure of steam in the boiler.

The method herein described of controlling. combustion in furnacesiwhich consists in regulating the feed of fuel and the I trolling combustion m {furnaces which consists in regulating'the supply of air to the combustion chamber and escape of products of combustion from the furnace by and in from the accordance with'the flow of steam boiler, and Varying the supply of air by and in accordance with variations of the static pressure of the steam.

7 The method of flow of steam herein described of con- "the rate of flow of steam trolling combustion in a furnace which consists fin-regulating the escape of gases from the furnace'andthe supply -of air and fuelv 1,aas,o22 I ing the supply of air and fuelin accordance with thevariations of static pressure. m: -8. The methodherein described ofreg u lating the combustion in furnaces iwhleh consists in regulatingthe fuel and air supply by and ht accordance with changes in the rate of flow of steam-from the boiler and changes" in the pressure of steam flowing from the boiler. i I v '9. The 'method herein described which consists'in utilizing the Vapor in a boiler at a pressure somewhat below the'normal boiler pressure to the furnace of the boiler, varying the rate ofsuch feed' by'and in accordance'with" and speeding up such feed on a drop of pressure below a predetermined minimum.

In testi JOHN M; riorwoo'n.

to control the feed of fuel and air from the boiler,

p mony whereof I have hereunto set 40 v, hand."

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