US1423335A

US1423335A - Steam boiler with forced-draft furnace

Info

Publication number: US1423335A
Application number: US366659A
Authority: US
Inventors: Kohler Conrad
Original assignee: Individual
Current assignee: Individual
Priority date: 1920-03-17
Filing date: 1920-03-17
Publication date: 1922-07-18
Anticipated expiration: 1939-07-18

Description

C. KOHLER.

STEAM BOILER WITH FORCED DRAFT FURNACE.

APPLICATION FILED MAR. 17, 1920.

1 4233359 Patented. July 18,1922.

awa e es wr t en.

STEAM BOILER WITH FORGED-DRAFT FURNACE.

i'neass Specification of Letters lPatent.

Patented July 18, 1922.

Application filed March 17, 1920. Serial No. 366,659;

To all w 7mm it may concern Be it known that l, CONRAD KoHLnR, a citizen of the Republic of Switzerland, residing at Hardturmstrasse 19, Zurich, Switzerland, have invented certain new and useful improvements in Steam Boilers with Forced-Draft Furnaces; and I do hereby declare the following to be a clear, full, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reterence'being had to the accompanying drawing and to letters or figures of reference marked thereon, which form a part of this specification. l I

This invention relates to improvements in steam boilers with forced draft furnaces and particularly to draft-furnaces in which the air is admitted into the ash-pit under the grate for increasing the draft and promoting combustion. a I

Steam boilers with forced draft-furnaces of the type mentioned above present the disadvantage that the opening of the fire door is always dangerous, as flames or at least noxious gases may be driven out by the forced draft when the fire door is opened.

The object of the present invention is to eliminate the drawback referred to. To this end ahlast device is provided which is connected to the fire box previous to the opening of the fire door, whilst the air current from the blower to the ash-pit is cut off. The blast device may be worked by the compressed air from the under-grate blower, in which case a change-over device is provided that is adapted to efiect a connection between blower and blast-device and to close the connection between blower and ash-pit. The blastdevice may also be worked by means of the draft induced by the running speed of the vehicle on which the boiler is mounted. v

The accompanying drawing illustrates by way of example several modes of carrying out the invention. All these are a plied to steam-locomotives, in which the danger, that the flame or noxious gases on opening the furnace door are driven into the cab, exists in a higher degree because the air-current induced .by the speed of the locomotive produces a depression in the cab.

In the drawing:

Fig. 1 is a diagrammatic longitudinal section through a locomotive fitted with improvements according to the invention.

above described manner.

Fig. 2 is a modification of a detail of Fig. ,4.

Fig. 8 is a longitudinal section through a locomotive showinga modified arrangement.

Fig. 41- is a longitudinal section through the lower part of the fire-box illustrating special means for reducing the pressure in the box.

Fig. 5 is a view similar to Fig. 4, showing undenpressuro means for-the ash pit.

An eight wheel locomotive isshown diagrammatically in Fig. 1. It is driven by a steam-turbine lplaced on the front of the locomotive, the details of the drive are not shown. When working normally the exhaust steam from the steam turbine is led to a surface-condenser (not shown in the drawing). When the locomotive is stopping or when an increase of the draft in the boiler furnace is necessary, the exhaust steam is led to a blast-device 2, from where it passes through the stack and, acting as an ejector, causes the gases in. the smoke box 4 to escape through the stack. When working normally a blower 5 compresses air and forces it through pipe 6 into the ash-pit 7. From there itpasses through the gate 8 and the fuel. The gases of combustion flow from the fire-box 9 through the boiler tubes 10, into the smoke box 41 and escape through the chimney I In ord .r to prevent the noxious gases from passing through the door 11 of the fire box into the cab when the door 11 is opened, it is necessary to stop first of all the blower 5 or to stop at least its effect on the combustion by closing the conduit 6 by means of a flap valve 12. Then the flap valve 14 inserted in the conduit 13 which has beenclosed up till then, is opened to eliminate quickly any over-pressure in the fire box 9 and to generate an under-pressure in this box. Fig. 1 shows the connections between the parts arranged and set in the The compressed air from the blower 5 flows along conduit 13 into the blast device 2 arranged inside the smoke box 4, the combustion gases contained in the fire box 9, the boiler tubes 10, and the smoke box 4:, are carried away with the air into the stack 3 and the desired under-pressure is thus generated inside the fire-box 9. The door 11 may now be opened without fear that flames or noxious gases willburst into the cab. To ensure that flap valve 12 has been closed and flap valve 1 L opened before the door 11 is opened, a lever 15 may be arranged in front of the door 11 by means of which lever and connecting rods 16, 17 connecting said lever up to the valves 12 and 14:, the latter are actuated. In order to open the door 11, lever 15 has first to be rocked on its fulcrum 18 towards the left which movement brings the

valves

12 and 14 into the desired positions. The furnace door 11 is locked until after this movement has been carried out.

When the furnace door 11 is to be opened during the running of the locomotive at full speed, under-pressure is produced by a pipe 21 the axis of the opening ofwhich is arranged vertically as shown in Fig. 4-, or which is bent towards the rear as shown in Fig. 2. The current of air induced in the pipe 21 by the speed of the vehicle generates an under-pressure inside said pipe, whereby combustion gases are drawn from the fire-box 9, until an under-pressure is generated therein. The conduit 21 can be closed by means of a flap-valve 28. Instead of connecting a conduit 21 to the fireboX 9, a pipe 25 fitted with a flap valve 9A may be connected to the ash-pit 7, Fig. 5.

The modification of the invention shown in Fig. 3 consists in a conduit 29, that can be closed by means of aflap-valve 28, which connects the ash-pit 27 with the smoke box. This construction is based on the assumption that the lifting power, to which the heated gases are subjected by the draft action of the stack 80, suffices to cause a quantity of gas to be drawn out of the ash-pit by conduit E29 and to escape through the stack 30, whereby an under-pressure is generated in the ash-pit 27 and the fire-box 31, sufficient to allow the fire-box door 32 to be opened without any danger. Obviously the connection from the blower 83 to the ash-pit 27 has to be closed by flap-valve 34 a short time before the furnace door is opened.

I claim:

1. In a steanrboiler with forced draftfurnace, the combination of a furnace consisting of a fire-box with fire door and closed ash-pit, an under-grate blower, a conduit connecting the blower and ash pit, a blast device, means including said conduitconnecting the ash pit with the blast device, and means for opening and closing the conduit and said connecting means so that the pres sure above atmospheric inside the fire box is removed and an under-pressure is generated.

2. In a steam-boiler with forced draft furnace, the combination of a furnace consisting of a fire-box with fire-door and closed ash-pit, an under-grate blower, a conduit connecting blower t0 ash-pit, a blast device, a closing device inserted in said conduit, and means to set said closingdevice so that the pressure above atmospheric inside the firebox is removed and an under-pressure is generated by said blower to permit opening the fire-door without danger.

3. In a steam-boiler with forced draftfurnace, the combination of a furnace consisting of a fire-box with firedoor and closed ash-pit, an under-grate blower, a conduit connecting blower to ash-pit, a blast device, a conduit connecting blower to blast device, a closing device inserted in each of said conduits, and means to set said closing devices so that the pressure above atmospheric inside the fire-box is removed and an underpressure is generated which permits opening the fire-door without danger.

a. In a steam-boiler with forced draftfurnace, the combination of a furnace consisting of a fire-box with fire-door and closed aslrpit, an under grate blower, a conduit connecting blower to ash-pit, a blast device, a conduit connecting blower to blast device, a closing device inserted in each of said conduits, and means to set said closing devices so that the connections with the blower are changed over from the ash-pit to the blast device whereby an under-pressure is generated into the fire-box which permits opening the fire-door without danger.

5. In a steam-boiler with forced draftfurnace, the combination of a furnace consisting of a lire-box with fire-door and closed ash-pit, an under grate blower,- a conduit connecting blower to ash-pit, a blast device, a conduit connecting blower to blast device, a closing device inserted in each of said conduits, and means to prevent the fire-door from being opened until after said closing devices have been set by said means so that the pressure above atmospheric inside the fire-box is removed. and an under-pressure is generated.

In testimony that I claim. the foregoing as my invention, I have signed in name.

CONRAD nonnnn.