US1480988A

US1480988A - Mechanical stoker for forced-draft furnaces

Info

Publication number: US1480988A
Application number: US628364A
Authority: US
Inventors: Bronold Johannes
Original assignee: Babcock and Wilcox Co
Current assignee: Babcock and Wilcox Co
Priority date: 1923-03-28
Filing date: 1923-03-28
Publication date: 1924-01-15
Anticipated expiration: 1941-01-15

Description

Jan. 15 1924.

J. BRoNoLD MECHANICAL STOKER FOR FORCED DRAFT FURNAGES Filed March 28 1923 2 Sheets-Sheet l Jan. 15 1924. 1,480,988

J. BRONOLD MECHANICAL STOKER FOR FORCED DRAFT FUBNACES Filed March 28 1923 2 Sheets-Sheet 2 @J4 Mee Fatented dan. l5, i924.`

JOHANNES BRONOLD, 0F STEIERMUHLE, GERMANY, ASSIGNOR TO THE BABCOCK W'ILCOX COMPANY, OF NEW YORK, N. Y.

' MECHANICAL STOKER FOR FORCED-DRAFT FURNACES.

Application led March 28, 1923. Serial No. 628,364.

To all whom it may concern:

Be it known that I JOHANNES BRoNoLD, a citizen of Bavaria, Germany, and residing at Steiermuhle, Saxony, Germany, have invented a certain new and useful Im provement in Mechanical Stokers for Forced-Draft Furnaces, of which the following is a specification.

The invention relates to mechanical stokers with forced draft furnaces, in which the draft is supplied only to the rear part of the grate while the front part of the grate is freely accessible, the sealing of the two parts of the grate from one another being effected by means of a box arranged between the upper and lower runs of the grate.

In accordance with the inwention, the front part of the grate is also enclosed, but is connected with suction means such as the suction inlet of the fan or the chimney or an injector-like device operated by the forced draft arranged in such manner that a partial' vacuum is formed in the front part of the grate.

Byvthis arrangement the following advantages are obtained. In the first place, if there is an excessive pressure in the combustion chamber, smoke or dust flowing out at the front of the grate is drawn off, so that there is no inconvenience caused to the staff attending to the Stoker. In the second place, owing to the partial vacuum at the iront of the grate the fire is drawn towards the front part of the grate, so that good combustion of the fuel is ensured and the fire cannot breakl up. Furthermore, the

y front part of the closure can be easily opened, Without, in any way, aecting the working of the forced draft so that the front part of the grate is actually accessible.

The invention is illustrated in the accompanying drawing in which Fig. l is a section of part of a furnace showing one embodiment. Fig. 2 being a similar view of a second embodiment 'adapted for use where the forced draught is supplied to anumber of boilers from a common air supply pipe.

Fig. 3 is a View looking down on the up per run of the grate, everything above the upper run being removed and part of the grate gear being also removed. In this view, parts are broken away and other parts beneath the grate are shown dotted.

arrangement The furnace chamber l is bounded in front by a fuel'hopper 2 and below by means of the upper run 3 of the mechanical grate. A box 4 is arranged below the fuel inlet, between-the upper and lower runs, which box for practical purposes, seals off the front part of the grate from the rear part. elow this box is a sealing arrangement 5 which bears against the lower run. The whole portion of the grate which is underneath the furnace chamber is, therefore, cut 0H from the front part by means of the fuel lying on the front of the grate and by the two seals 4 and 5. Below the rear part of the grate, forced draft is introduced through a'duct 6.

The front part of the grate is closed in by means of a casing 7 provided with a door 7 adapted to open outwardly. When the door is opened, access can be had to the front part of the grate, so that a fire slice can be used. The space thus closed 1n at the front part of the grate is connected, in the embodiment shown in Figs. 1 and 3, to a duct 8 by means of openings 81 in the floor beneath the grate. Leading upwardly' from duct 8 is the inlet conduit` 82 of the fan 83. An opening 84 is arranged in the wall 85 to admit air to the conduit 82. The air thus entering the fan 83 is forced out and down and is admitted in duct 86 through opening' 87, whence it flows into l duct 6 and beneath the rear ortion of grate 3. In the duct 8 is arrange a pivoted damper operable by means of a spindle 10 with a crank 11. The arrangement is such that, when the damper 9 is closed the crank engages the door1 7', so that the latter cannot be opened before the damper 9 is opened.

In the embodiment shown in Fi 2 the space enclosed in the front part of t e grate is connected by means of a duct 18 with a chamber 19 which is tapered to form a nozzle leading to a duct 16, which leads to the rear part of the grate.

Similarly to the embodiment previously described. a furnace chamber 1 is bounded in front by fuel hopper 2 and below by means of the upper run 3 of the mechanical grate. A box 4 is arranged below the fuel inlet between the upper and lower runs, to seal ofi' the front part of the grate from the rear part. Below this box is a sealing 5 which bears against the lower run. In this manner as in the'previously described embodiment, the entire portion of the grate 3 beneath the furnace chamber 1 is effectively sealed from the front part by means of the fuel lying upon the front part of the grate and by the two seals 4 and 5. The front part of the grate is closed in by. means of a casingl provided with a door 72 by means of which access may be had to the front part of the grate when it is necessary to lbar the grate or for any other purpose.

The nozzle formed as above described is connected to distributing piping 21, which serves to supply forced draft for several boilers. The wall-forming plates 2O can be adjusted by; means of levers indicated in dotted lines, to vary both the amount of the constriction in duct 16 and the effective cross-sectional area of the duct 18, so that it is possible4 to work under the most favourable conditions.

The modus operandi is as follows Forced draft is forced through the duct 16 (from the distributinn piping 21 in the arrangement shown in `ig. 2) under the rear part of the grate. As soon as there is a pressure in the combustion chamber 1, the flue gases forced into the front closed-in space are drawn off. At the same time, however, owing to the partial vacuum in the closed-in space, a. suction action is exerted on the fuel in the front part of the combustion chamber so that the lire is drawn to the front and cannot break up.

As the part of the stoker under pressure is sealed from the front part of the grate, the opening of the door 72 has no prejudicial effect on the. working of the furnace.

1. In combination With a chain grate stoker, means for supplying forced draft to the rear part of the grate, sealing means between said rear part and the front part of the grate, an enclosure for said front part, said enclosure, together with the sealing means, defining in part achamber enclosingthe end of the grate, and means for maintaining Said chamber under diminished pressure.

2. In combination with a chain grate Stoker, means for supplying forced draft to the rear part lof the grate, sealing means between said rear part and the front part of the grate, an enclosure for said front part, said enclosure, together with the' sealing means, defining in part a chamber enclos* neeoeee ing the end of the grate, means for maintaining said chamber under diminished pressure and means for regulating said suction action.

3. ln ,combination with a chain grate stoker, means for supplying forced draft to the rear part of the grate, sealing means between said rear part and the front part of the grate, an enclosure for said front part, said enclosure, together with the sealing means, defining in part a chamber enclosing the end of the grate, and means for maintaining said chamber under diminished pressure, said means comprising an injector device operated by the forced draft.

Il. ln a. furnace, a mechanical grate, a duct having a constricted portion for supplying forced draft to the rear o f said grate, sealing means between said rear part and the front part of the grate, an enclosure for said front part, such enclosed region having passage communicating with said duct at said constricted porJA whereby a suction may be created in said enclosure by the forced draft.

i5. ln a furnace, a mechanical grate, a duct having a constricted portion for supplying forced draft to the rear of said grate, sealing means between said rear part and the front part of the grate, an enclosure for said front part, such enclosed region having .a passage communicating with said duct at said Constricted portion. whereby a. suction may be created in said enclosure by the forced draft and means for varying the amount of said constriction.

6. ln a furnace, amechanical grate, a duct having a constricted portion for supplying forced draft to the rear of said grate. sealing means between said rear part and the front part of the grate, an enclosure for said front part, such enclosed region having-a passage communicating with said duct at said constricted portion, whereby a suction may be created in said enclosure by the forced draft, means for varying the amount of said constriction and independent mea-ns for regulating the effective size of said passage.

ln testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.l

JOHANNES BRGNOLD. l-itnesses AoAri'roN SoMoN, nnnnrn Fincas.