Patent GB-190113357-A (GB)
Title: Improvements relating to Regulating Devices especially adapted for Apparatus for Operating Valves and Dampers.
Inventor: WRENN BEVERLY WELLFORD
Filed: 1901-07-01
Granted: 1901-08-03
Abstract: 13,357. Lake, H. H., [Wrenn, B. W.]. July 1. Relay motors.-Relates to regulators, and especially to regulating-devices for furnace valve and damper-operating apparatus. Broadly, the invention consists of relay apparatus in which the application of a comparatively large power may be controlled by means sensitive to variations of great delicacy. The apparatus comprises a power motor for operating the valve, damper, or other mechanism, a controlling-device operated by variations of pressure, temperature, or the like, and an actuating- device by which the motor distributing-valve or its equivalent is operated. The invention is shown in Fig. 1 as applied to the opening and closing of dampers in furnace uptakes. The motor 6 is preferably a hydraulic motor, the piston-rod 10 of which is connected by rods, levers, chains, or cords with the furnace damper. The strokes made by the motor are determined by an oscillating plug valve. This is worked through the medium of a rocking plate 21 by the actuating-device, which, in the example illustrated, is a pivoted falling weight 24. This weight is set in position upon each stroke of the motor piston in either direction bv means of tappets on a rod 44 acting on the arms 27, 28, and is tripped or released by the controlling-device, which in this example is in the form of a diaphragm 33, whenever the conditions in the furnace require the damper to be operated. As the weight falls first towards one side and then towards the other, the shank 24 operates the valve by striking the pins 22, 23. The weight of the diaphragm and its connected parts and the normal suction on it are counterbalanced by a weight 36. Suppose that, when the fire is drawing properly, the suction on the diaphragm is 20 oz., the counterbalance is adjusted so that, on a reduction of 2 oz., caused, say, by opening the furnace door, it overbalances and releases the actuating-weight, thereby operating the motor distributing-valve. The resulting stroke of the motor closes the damper, reducing the pull on the diaphragm practically to zero. The subsequent closing of the door raises this pull, say, to 2 oz. ; and thereupon, owing to the action of a second weight 54 brought into operation by the closing of the damper, the releasing-device is again tripped, and the damper is consequently opened. In order to ensure that, when the motor acts, it shall complete its full stroke, it is necessary to guard against premature operation of the motor distributing-valve. In this example, the valve-actuating weight is lifted only by the completion of a stroke, and therefore cannot act prematurely. In the modification shown in Fig. 10, a locking-device is applied which altogether prevents the tripping of the releasing-device except at the end of each full stroke. In this example, the valve-actuating device consists of two springs 68, 69 compressed during the movement of the motor piston, retained by latches 76, 77, and released by the tripping-lever 78. The tripping- lever, except at the end of each full stroke, is locked by a plate 73, which allows the lever 78 to move only when certain notches in it are brought into suitable position.