Patent GB-190720907-A (GB)
Title: An Improved Door-controlled Draught Regulating Apparatus for Furnaces
Inventor: MEDERER ROBERT
Filed: 1907-09-20
Granted: 1908-09-21
Abstract: 20,907. Mederer, R. Sept. 20. Air supply, regulating; blast apparatus; doors; smoke - consuming.-The steam jets of a blast apparatus supplying air above and below the grate of a steam-generator or like furnace are automatically controlled by means of valvular devices on a combined steam and dash-pot cylinder, which forms the hinge or pivot of the fire-door. The apparatus is brought into action by the opening and closing of the door, and also, on a locomotive, by the movements of the regulator lever. Hit-andmiss air regulators on the door are operated respectively by hand and by the piston-rod of the cylinder. The door 20 is connected to the rotatable cap 50 of the combined steam and dash-pot cylinder 22, which forms the fixed part of the hinge. The cylinder 22 has a differential piston 26 connected by a piston-rod 27 to a dash-pot piston 26<a>, which operates the automatic air-supply regulator 28 by means of rods 45, 46, an arm 61, and a lever 64. The pistons are raised and lowered by steam supplied through the port 40, and the apparatus is arranged so that the air is injected into the furnace while they are uplifted, and is cut off by their descent. The duration of the injection is regulated by the dash-pot 26<a>. The upper part of the cylinder 22 is fitted with a cock 51, which rotates with the cap 50 as the door is opened, and controls the blast apparatus as follows. Steam at all times obtains access through the port 40 to the cylinder 22, beneath the piston 26. While the door is shut, the steam also passes through the passage 54, the groove 52, Fig. 8, in the cock 51, and the port 7 in the cylinder end to the top of the steam cylinder, so that the piston remains in its lowest position, as shown in Fig. 1. As the door is opened, the cock 51 rotates in its casing 53, and the groove 52 is moved away from the passage 54, and over to the exhaust passage 42 connecting it with the passages 7, 56, 6 in the cylinder end and valve casing. The steam above the piston 26 is thus exhausted, and the piston rises, operates the automatic regulator 28 on the door, and uncovers ports 55, 12 which admit steam to pipes leading to the blast nozzles. The port 12 conducts the steam to the pipe 70, and thence through the regulator 69 to steam jets attached to the upper part of the doorway. The port 55 conducts the steam to a passage fitted with a spring-loaded valve 59, Fig. 3, which closes when the nose 72 is withdrawn by the rotation of the cap 50, so that it is not until the door is shut again that the steam passes through the port 55 to nozzles 60, Fig. 1, at the sides of the doorway, and to other nozzles beneath the grate. When the firedoor is again closed, the exhaust passage 42 is shut, and steam is re-admitted to all parts of the cylinder 22, so that the piston 26 is forced downwards, and eventually closes the port 12 and wholly or partly closes the port 55. The cut-off of the port 55 may be adjusted by the screw 63, so as to afford a constant supply, if desired, of a small quantity of steam to the nozzles 60 &c. In a modification for locomotives, the steam -supply pipes 55<a>, 40<a>, Fig. 11, which have functions like the parts correspondingly numbered and shown in Fig. 1, are controlled by a valve 74, which is opened, when stopping the engine, by the heel 37 on the regulator handle. An additional pipe 9 admits steam to the hollow spindle of the cook 51<a>, Fig. 10. This steam, passing through the port 80, forces down the spring-lifted piston 75, and brings the groove 79, which is thus connected to the passage 56<a>, opposite the exhaust port 42<a>, so that the piston in the cylinder 22<a> is raised, and the apparatus operates as described above in connexion with the opening of the fire-door. When the locomotive is again started, the valve 74 closes and cuts off the steam, which condenses in the pipe 9 &c. The spring 77 next raises the piston 75, and connects the steam-supply pipes with the upper end of the cylinder 22<a> by means of the groove 78 and the passage 56<a>. The piston then descends as described above.