Check-valve—a valve placed between the feed pipe and the boiler to prevent the return of the water, etc.
Brine-valve—a valve which is opened to allow water saturated with salt to escape. In marine service it is “a blow-off valve.”
Ball-valve—a valve occupying a hollow seat. These valves are raised by the passage of a fluid and descending are closed by gravity.
Angle-valve is one which forms part of an angle, see [Fig. 137].
The double-seat valve or double-beat valve presents two outlets for the water. In the Cornish steam engine this is called the equilibrium-valve, because the pressure on the two is very nearly equalized.
Three-way cock is one having three positions directing the fluid in either of three directions. This is illustrated in [Fig. 138]. The three-way valve is also illustrated on page 259, [Fig. 136].
Four-way cock is one having two separate passages in the plug and communicating with four pipes.
Gate-valve—a valve closed by a gate. This is illustrated in [Fig. 140].
Swing or straight-way valve—this is shown in [Fig. 141], page 261.
Throttle-valve.—This is the valve used to admit steam to the engine and so termed to distinguish it from the main stop-valve located near the boiler—to throttle means to choke—hence the throttling of the steam.