Section 10
10. A Valve for a Pump.
The following is the
construction of the valve referred to.
Take two rectangular plates of
bronze of the thickness of a carpenter's rule, and measuring about one
finger's breadth (7/10 of an inch) on each side. When these have been
accurately fitted to each other, polish their surfaces so that neither
air nor liquid may pass between them. Let A B C D, E F G H,(fig. 10) be
the plates, and in the centre of one of them, A B C D, bore a circular
hole about 1/3 of a finger's breadth (1/4 of an inch) in diameter. Then,
applying the side C D to E F, let the plates be attached by means of
hinges, so that the polished surfaces may come together. When the valve
is to be used, fasten the plate A B C D over the aperture, and any air
or liquid forced through will be effectually confined. For by the
pressure exerted the hinges move, and the plate E F G H opens readily to
admit the air or liquid; which when inclosed in the air-tight vessel,
presses on the plate E F G H, and closes the aperture through which the
air was forced in.
Section
11.
Index.