Figs. 196, 197.
Armored pump valves. As represented in Fig. 193 this is a valve made by stamping a metal disc out of steel which is then plated with copper to protect the surface and secure the adhesion of the rubber. Marginal notches are left on the inside and outside edges of the plate and rubber is moulded around these, and vulcanized to the required hardness; a brass or copper plate may be used instead of steel and the plates may be corrugated radially to increase their stiffness when the area of the valve is large.
Experience proves that the water valve adopted together with its location, has a material bearing upon the efficiency of any pump; easy seating valves are subject to more or less slippage, owing to tardy seating; the location of water valves should be above the pump cylinder, inasmuch as in operation the pump is always primed, while if suction valves are placed below, any wear on the valves or valve seats, or obstruction under the valves, will cause the water to leak entirely out of the water cylinder, making it necessary to prime the pump before it can be started.
Note.—The screwed seat is shown in Fig. 194, Stud Fig. 195, Metal Valve Fig. 196, Spring Fig. 197, and all put together in Fig. 198.
Fig. 199.
Valve seats, bolts and springs should be of the best composition or gun-metal; and valves of composition, or hard or soft rubber, to suit the duty such pump is required to perform. These valve seats are screwed into the valve plate, and valves may be changed from composition to rubber by merely removing bolt, and substituting one for the other without removing the seat. This is of great advantage where a pump is to be used for hot water after being used for cold water.
Fig. 200.