US838338A - Apparatus for regulating combustion in furnaces. - Google Patents

Description

No. 838,338. PATENTED DEC. 11, 1906.

I T. w. JOHNSON. APPARATUS FOR REGULATING COMBUSTION IN FURNACES.

APPLICATION FILED JAN. 22. 1906.

2 SHEETS-SHEET 1.

No- 838,338. PATENTED DEO.11, 1906.

T. W. JOHNSON.

APPARATUS FOR REGULATING COMBUSTION IN FURNACES.

APPLICATION FILED JAN. 22, 1906.

2 SHEETSSHEET 2.

rm om "UNITED STATES PATENT OFFICE.

APPAFIATUS FOR REGULATING COMBUSTION IN FURNACES. v

Specification of LettersjPatezit.

, application filed January 22. 1906. Seria1No. 297.358-

Patented. Dec. 11,1906.

To all whom it may concern:

Be it known that I, Tnotms W. JOHNSON,

a citizen of the United States, residing insuch combustion will at all times be effected under uniform or substantially uniform conditions, such conditions being dependent upon gas-pressure in the combustion-chamber exerted against a normally constant counter-pressure and preferably against atmospheric pressure outside 'of the furnace; I

In the accompanying drawings, Figure 1 represents a steam-boiler furnace provided with one form of combustion-regulating apparatus in accordance with my invention, and Fig. 2 illustrates another form of such combustion-regulating a paratus. I

Fig. 1 illustrates an or 'nary t e of boilerfurnace, 1 representing the close ash-pit; 2, the pipe for supplying to said ash-pit air under pressure for supporting combustion; 3, the combustion-chamber; 4, thestack, and 5 I 1 the pivoted damper in said stack,'all of these parts being constructed in accordance with the present practice. 'Mounted at any available point upon a wall of the combustionchamber is a casing 6, which may be of any desired cross-sectional form and area, the

chamber 7 within this casing being in the present instance in communication with the combustion-chamber of the furnace through a neck 6", which passes through an opening 7 in. the rear wall of said combustion-chamber.

Wall of the casing.

Within the chamber 7 is a swinging-plate or diaphragm 8, which is pivoted adjacent to one wall of the casing 6, the pivot in the construction shown bein adjacent to the top his'diaphragm fits the casing 6 as closely as is com atible with its free swinging movement, an as the casing 6 is open at the outer end the di hragm is exposed at all times on its outer aceto atmospheric pressure and on its inner face'to the pressure maintained within the combustionchamber of the furnace. Hence as the latter pressure varies in respect to the normally fixed atmospheric pressure the diaphragm is caused to swing, and this swinging move ment is utilized for the purpose of operating the mechanism 'for controlling the air- .for this air into or from the supply :or draft of the furnace, or both. 1 Many forms of mechanism may be utilized urpose. Hence it should be understood that the mechanism which I have shown in the present instance is only for purposes of illustration and does not constitute an essential part of my invention. Projecting from the pivot-spindle 9 of the diaphragm 8 is an arm 10, which operates the stem 12 of a valve 13 for controlling the flow of water or other fluid under pressure to the lower portion of a damper-operating cylinder14, the latter having a piston 15', with weighted rod 16, which is connected by a cord 17, assing over a ids-pulley 18, to a weig ted lever19 on t e pivot-s indle of the stack-damper 5. Hence when t e piston 15 rises in the cylinder 14 said damperis moved in one direction, and when the iston descends in the cylinder 14 the am or is moved in the opposite direction, free ow, of

inder being permitte ow of fluid to .or from the lower. erid of the cylinder 14 therefore controls the movement of the piston therein and the consequentoperationof the damper, the cutting off of such flow serving to lock the damper in the'position to which it had previously been adjusted. The casing of the valve 13 has a fluid-inlet 20, a fluid-out .let 21, and a pi e 22, leading to thecylinder 14,-and. the vave-stem 12 has two disks 23 and 24, the former constituting the go verning element of the valve and the disk 24 being a pressure+equalizing disk. A

When the disk 23 is in the upperFportion of the cyl- Y in Fi 1, it closes the inlet en of the pipe 22,

and once locks the damper in the positionv previously assumed by-it, movement ofthe disk 23 in the -direction of the arrowmpljmitting flow of fluid under pressure from the inlet-pipe 20 into the pipe 22, and therefore to the cylinder 14, so as to raise the piston in.- the latter, while movement of the disk 23311. the direction of the arrom from the position shown in Fig. Lopens, 't e connection between the i e 22,-and the outletipe 21 and permits discharge of fluid from t e cylinder 14} and descent of the piston -therein.

The, parts are so arranged that when the p'ressuredn the combustion-chamber is less than r'atmospheric pressure the diaphragm 8-, swinging inwardlyunder such atmos heric loo to the damper 5, thereby checking the draft until the pressure within the combustion- 4 chamberagain equals or ap roaches atmospheric pressure and the iaphragm 8 returns to its vertical and normal position. When, on the other hand, the pressure within the combustion-chamber 3 is. greater than atmospheric pressure, the diaphragm 8 will swing outwardly, and thiswi-ll result in an opening of the damper 5, thereby providing a freer outflow from the combustion-chamher and lowering the-pressure therein until it again equals or approaches atmospheric pressure and causesthediaphragim to again assume its vertical and normal position.

It has been found in practice that the diaphragm 8 is so sensitive in its action that it is' affected by slight changes of pressure in the combustion-chamber, and a condition'corre spondi-ng closely to atmospheric pressure is constantly maintainedin said combustionchamber, substantially uniform combustion being maintained at all timesirrespective of variations in the depth or other conditions of the fuel-bed or in the pressure of the blast, the result being that when the furnace-door is open there will, on the one hand, be no inflow of cold air to the combustion-chamber and, on the other hand, no outward blast of hot gases therefrom.

' In Fig. 2 I have illustrated my invention in connection with an electromagnetic controlling device, the arm 10 of the swinging damperin this case terminating in a switchfinger 10*, which vibrates between the opposite terminals 25 and'26 of an electric circuit containing two electromagnets 27 and 28,

rovided with a solenoid-core 29, the latter aving a cross-head 30, whose opposite ends are contained between collars 31 on rods 32, suitably guided on opposite sides of the magnets and normally maintained in mid-positionby means of up er and lower coiled sprin s33, interposed between the collars 31 and t e fixed guides 34 for the rods 32. The lower ends of the rods 32 carry a cross-head 35, which is connected to the stem 36 of a valve 37, the latter having an inlet 38 for water or other fluid under pressure, two outlets 39- and 40 communicating, res ectively, with the up er and lower ends of a amper-op'erat ing cy inder 14 and a discharge-outlet 41, communicating directly with one end of the valve-chest 37 and through a pi e 42 with the opposite end of the same. he valvestem 36 has two disks 43 and 44, which normally close the outlets 39 and 40 and cut off communication between the cylinder 14 and the inlet-port 38 or discharge-port 41 0f the valve-chest. i

When the swinging diaphragm 8 occupies its normal or vertical position, the switchfinger 10 is free from contact with either of the terminals 25 and 26.. Hence neither of the electromagnets27 or 2 8 is energizedfanjd the solenoid-core 29 occupies a mid-position corresponding with the normal or like position of the valve-disks 43 and 44. When, however, the diaphragm 8 swings outwardly, the switch-finger 10 is caused to contact with the-terminal 25, the upper magnet 27' is en ergized, the solenoid-core is raised, and corresponding movement is imparted to the valve-stem 36, thereby opening the upper end of the cylinder 14 tothe fluid-inlet 38 and the lower end of said cylinder to the fluid-outlet 41 and causing a descent of the piston 15 in the cylinder and a movement of the stack-damper to increase the draft of the stack. When, on the other hand, the diaphragm 8 swings inwardly, the switch-finger 10 is moved so as to contact with the terminal 26, the lower magnet 28is energized,

the solenoid-core 29 is depressed, and there is alike movement, of the valve-stem36, so as to open communication between the lower end of the cylinder 14 and the fluid-inlet 38 and between the upper 'end of said cylinder and the outlet 41, thus causing a rise of the piston 15 in the'cylinder and a movement of the damper 5 to check the draft in the stack.

While I prefer in all cases to use the swinging diaphragm 8 because of the sensitiveness of the same, it will be evident that a flexible diaphragm or a sliding piston might be used in place of the same, any of these devices -be ing intended to be covered by the term SSS ferred to therein, and instead of controlling the movement of the stack-damper alone the movements of said primary member may be caused to control a damper in the pipe 2, which supplies the air-blast to the closed ashpit .of the furnace, such a damper being illustrated at 46 in 2, or the movement of the primary member 8 may be transmitted both to the stack-damper and to a valve in the steam-pipe which supplies the blast-fan-driving en ine, such a valve being illustrated at 47in ig. 1, or either the blast-pipe damper or the engine-regulatingvalve may be used in connection with an open stack or with a stack having a normally fixed damper, or my invention may be employed for regulating either the air-supply orstack-draft, or both, in a furnace having natural draft instead of forced draft, what I consider to be the essentially novel feature of my invention being the utilization of varying pressures within the combustion-chamber of the furnace for effecting controlv of the combustion.

Any normally fixed pressure, such as that i of a weight or a body of water .or other fluid acting against the primary element ofvthe regulating apparatus, may be employed in place of atmospheric pressure as the agent: opposed to the combustion-chamber pressure; but atmospheric pressure is preferred, as it dispenses with all means-for preventing leakage and permits the use of the swinging diaphragm or other freely-moving body as the primary element.

No attempt has been made to show in the drawings the relative proportions of the parts, as this would necessitate too small a scale for some of them. 7

I claim' Y 1. Combustion-regulating apparatus for fiurnaces having as elements a regulating device actuated by fluid under pressure, a valve governing the operation of said device, and a swinging plate supported so as to tend to re main in a neutral position under the action of gravity and placed" to govern the movement of said valve, said plate being acted upon in one direction by a normally fixed pressure and in the other direction by the pressure in the combustion-chamber.

2. Combustion-regulating apparatus for furnaces having as elements a regulating device actuated by fluid under pressure, a balanced valve governing the operation of the same, and a swinging plate connected to said valve and supported so as to tend to maintain the valve in its closed position under the action of gravity, said plate being acted upon in one direction by atmospheric'pressure and i in the other direction by the pressure in the combustion-chamber. I i

3. Combustion-regulating apparatus for furnaces having as elements a regulating device actuated by fluid uiider ressure, a valve governing the operation 0 said device, a swinging plate su ported so as to tend to remain in a neutral position under the action of gravity, and provided with a pair of contaots, a movable member connected to the plate and coacting with said contacts, and electrical apparatus connected to the valve so as togovern the operation of the same and included in the circuit with said contacts, the plate being placed to be acted on in one direction by a normally constant pressure and in the other direction by the pressure in the combustion-chamber.

In testimony whereof I have signed my name to this specification in the presence of two subscribing Witnesses.

THOS. w. JOHNSON.- Witnesses I 1 WALTER OHIsM, Jos. H. KLEIN.

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