Patent GB-189911458-A (GB)
Title: Improvements in Compressed Air Water Pumps or Elevators.
Inventor: MITCHELL MARCUS LAFAYETTE
Filed: 1899-06-01
Granted: 1899-07-29
Abstract: 11,458. Mitchell, M. L. June 1. Direct air-pressure apparatus.-C o n s i s t s chiefly of improved valves and valve mechanism by which it is ensured that the air supply shall not be shifted from one chamber to another until one chamber is completely filled and the other completely emptied, and by which also the air pressure in a chamber is raised gradually. The two chambers 21, 22, with valved inlets and outlets 24, 38, each have an independent primary valve 67, the two valves jointly controlling the double-ended piston 48, which is connected with the main valve 50 so that there is some lost motion between them. Pipes 70, 71 connect the primary valve casings with the opposite ends of the main valve casing 46, and, by means of the valves 67, are put in communication alternately with the exhaust and with a secondary air supply of higher pressure than that controlled by the valve 50. With the parts in the position shown, water is being forced from the chamber 21 and is entering the chamber 22. The connection between the floats and weights 93, 90 and the valves 67 is such that the weights move their connected valves on falling, and the floats on rising. Thus, on the chamber 21 becoming empty, its valve 67 puts the right-hand end of the casing 46 in communication with the secondary air supply through the pipe 70, thus moving the piston 48 to the left against the lower pumping pressure which, by reason of the passage 51<a>, exists in the left-hand end of the casing 46. On the piston covering the passage 51<a>, the pressure in both ends becomes equal, since the left-hand end of the casing 46 is connected by the pipe 71 with the secondary air supply. The valve 50 is thus stopped, so as to close the port 43<a> and leave the part 43<b> open to exhaust, until, on the chamber 22 being filled, the float 93 moves its valve 67 so as to connect the left-hand end of the casing 46 with the exhaust. This causes the piston 48 to open the passage 51<b>, and admit exhaust pressure from the chambers 22 to the right-hand end of the casing 46. The port of the passage 51<b> being bigger than that of the pipe 70, the pressure in the right-hand end of the casing 46 now falls, thus stopping the valve 50 with the port 43<b> closed, and allowing the gradual raising of the pressure in the chamber 22, until sufficient to give the piston 48 its final movement and open the port 43<b> to the main supply. If the chamber 22 had been filled before the chamber 21 had emptied, the piston 48 would make only one stop, viz., while the pressure rose in the chamber 22. In this case the passage 51<a> would be closed by its check valve 52 closing upwards. If the piston 48 becomes clogged after standing, the main supply is cut off, and the secondary supply, which is taken direct from the air reservoir, is admitted alternately to the opposite ends of the casing 46 by moving the valves 67 by hand gear provided for this purpose. The domes 100 in which the floats 93 fit have valves which are open while the chambers are filling, but are closed by the rush of high-pressure air. Slightly-modified valves for a single-chamber apparatus are described.