Patent GB-191403707-A (GB)
Title: Improvements in Pumps, Engines and the like.
Inventor: ZWICKY JEAN
IPC: F04B13/02
Filed: 1914-02-12
Granted: 1915-02-12
Abstract: 3707. Zwicky, J. Feb. 12. Double - acting piston pumps; combined liquid and air pumps; valves and valve seats, arrangement of.-In pumps and fluid-pressure motors of the kind comprising two pistons on a common rod between which are located the valves and working chambers, the valves are so arranged as to permit flow of the fluid throughout the whole circumference of the working chambers. In the form of pump shown in Fig. 1, the pistons 7 on the rod 5 work in open-ended cylinders 1, 2, which are connected at their inner ends to a casting 3 containing a ring of inlet ports 53 and two rings of outlet ports 51,52. Thecylindrical sleeve valve 11 is provided with a row of ports 54 always in register with the ports 53, and with spring-pressed lift valves 12 which control the entrance of the fluid to the working chambers. The valve 11 is moved by the fluid pressure in the working chamber. In another form, the valve 11 is in two overlapping parts, which are pressed apart by an intermediate spring, and the outer edges fit between the casting 3 and the cylinders 1, 2, thus cushioning the valve. In another form, the outer end of one of the cylinders 1, 2 is closed and provided with gas inlet and outlet valves, so that the outer end of the piston 7 acts as a gas compressor. The lower portion of the closed cylinder may be of different diameter from the upper portion, with a piston modified to fit it, so that the gas and liquid may be supplied in any proportion. In another form, the valves 12 are dispensed with, and the inlet and outlet ports are controlled by a modified cylindrical valve. The form shown in Fig. 7 is a motor adapted to serve as a water-meter. The valve is pushed half-over by the piston 7 near the end of its stroke, so as to close the inlet and outlet ports to the working chamber and permit pressure water to pass from the inlet 71 by way of the reduced portion 33<a> of the piston-rod and through a small port 33, to complete the movement of the valve. In the meter shown in Fig. 8, a fixed abutment 34 is provided between the outer and inner portions of the valve 35 to take the greater part of the water pressure. The valve is pushed half-over by the piston 7 at the end of its stroke, a spring 36 between a cap 37 and a member 38 carried by the piston being thereby compressed; the inlet being then cut off from the chamber 1, the spring is enabled to expand and complete the movement of the valve. The valve is cut away at 35 to allow part of the pressure in the chamber 2 during the upward stroke to be taken by the port 34. In the form shown in Fig. 9, a fixed cylinder 41 provided with a ring of inlet and outlet ports at each end coacts with two correspondingly ported cylinders 42 slidably connected to a sleeve 43, which is loose on the rod 5 and is moved by the piston at the end of its stroke. A pin 44 on the sleeve is thereby moved along an oblique slot 45 in the port 41, the sleeve, together with the valves 42, is thereby rotated, and the connexions between the ports in the valves 42 and those in the cylinder 41 are reversed at both ends.