Patent GB-166163-A (GB)
Title: Improvements in and relating to chaingrate, and the like stokers
IPC: F23H11/12
Filed: 1917-05-09
Abstract: 166,163. Bennis, A. W. May 9, 1917. Grates; air supply, regulating; ash-pits; mechanical stoking; furnace fronts; liquid-fuel furnaces.-In connection with an automatic stoker means are provided for sealing the furnace to allow the use of greater internal pressure, for cooling parts of the stoker and the framework, and for preventing emission of flames and hot gases through joints between the stoker and adjacent parts of the furnace structure. In the inclined chain-grate furnace shown, air under pressure is supplied beneath the grate by a trunk 21, and is distributed under control of dampers 28 to chambers 22 - - 27, of which the first and the last are around the front and rear sprockets respectively, while the remainder are beneath the fuel-burning portion of the grate. The chambers 23 - - 26 are separated from one another by swinging plates 87, and from the end sprocket chambers by plates 81, 82, 85, 86, Fig. 12. The plate 81 is loosely mounted so that it can rise and fall with the movement of the links of the chain, and a tight joint between it and the cross plate 85 is maintained by a roller 84. Similar sealing-devices may, if desired, be used between the chambers 23 - - 26 instead of the swinging plates 87. Air from the chamber 22 is passed through external ducts to a chamber at the rear of the hopper, closed at the top by a removable cover 39, and to the chamber 3 between the hopper outlet and the gate 4, which regulates the thickness of the fuel bed. The cover 39 fits into a sand or similar seal, and is provided with an adjustable relief valve 41 for preventing excessive air pressure in the neighbourhood of the hopper. The gate 4 is formed with passages, through which air from the chamber at the rear of the hopper is delivered to promote the ignition of the fuel. The whole of the front of the stoker is enclosed bv a casing having doors giving access to the fuel chamber 3, the front sprocket chamber 22 and the space beneath the grate, and the housing enclosing the sprocket chamber is provided with a hopper 51 for the collection of ashes &c. The side jamb columns 54, Fig. 4, of the stoker are hollow and are connected at the top by a casing 57 having air guiding and cooling ribs 58 and a relief valve 68. Air enters the columns from the space beneath the grate through ports 53, and is delivered through ports 62 in the casing 57 to the hollow front plate 63, from which it leaks through spaces between the front plate and the brickwork 56 and the back of the gate 4. Air is also admitted from the front plate to the space 66 beneath the casing 57. The air may be passed up one jamb column, through the casing 57, and down the other column, from which it may escape to the atmosphere, or may be utilized for combustion purposes. The rear sprocket chamber 27 is supplied with air by leakage through the grate links and from adjacent air seals, and from it air may pass into a channel 69, Fig. 8, between the dumping-plate 70 and an air-guiding plate 71. The dumping-plate bearer 74 is hollow and is fitted with a hinged door 75. At the sides the bearer 74 connects with air boxes 78 leading to hollow cill plates 79, Fig. 10, of channel, Z, or other suitable section, having depending flanges 116, which form with troughs 115 sand seals at the sides of the grate. Between the side grate frames 100 and the walls of the furnace are chambers 99, sealed at top and bottom bv rollers 106, 107 resting on bevelled surfaces, and at the rear end by a plate 98, Fig. 12, supported between ribs in the frames 180 and on a shoe 96 which seals the rear end of the main air chamber beneath the grate. The front end of each chamber 99 its sealed by a strip 104, Fig. 4, clamped by bolts 105 to a flange on the grate frame and a plate forming a continuation of the side walls 55. If desired the chambers 99 may be divided by sealing-plates into compartments corresponding with the air chambers beneath the grate. If desired, oil-fuel burners may be fitted in the side walls of the furnace.