\ V I 



trom passing. As the student will be quit* familiar 

 * th the conim { such as U uneti in dwelling- 



house* we need nut illu .-re. 



70 shows * cock of considerable stxe, which mny be 

 used for water or steam under high pmun. The \>. 



prevented from coming on- 



cover which U Sfcuwl to the ca*t ;r Ktud boll \ 



.iniiul u- ri<lge of rectangular section projecting from the unl-r 

 tide of the cover, an i corresponding races* on th- 



top of the caning, serve* itf arv 



concentric, and prevent* leakage. Leakage at - 



a gland and The* t") 



Miade square to receive a handle for turn: 

 Hie size of a cock is tak lie bore ot 



draw the 

 views of this cock shown in fig. ?0 then draw a half end eh 



hr.uiKh the centre of the plug. Scale 6 inches 

 to afoot. 



Instead of dm pipe on the two sides of the 



> the same straight line as in fig. 70, one may be show; 

 ceeding from the bottom of the casing, so that the fluid will have to 

 pass througl : m of the plug and through one side. 1 



:tion arrangement. 

 All the parts of the valve and casing in this example are made 



! ve for regulating the supply 



f water to a tank is called a ball valve when it is operated 

 y a hollow ball which float* on tho watt r in flu- tank. 

 e water in thu tank i -i.-os t.> the highest level the ball is 

 ised and the valve is closed, and when the water-level falls 

 e ball is lowered, the valve opens and more water is ad* 

 1 shows Underhay's equilibrium ball valve. 

 ho back end of the vsl vr-spmdle carries a pi*' 

 orks inn Through the spin< : is a hole 



enables the water-pressure to act on the piston, and, as 

 e area of same as that of tl.- 



A balanced, and only a small force is necessary to open 



r close it. A Imd n pe is soldere.i rass union 



, aod the water in i through H into the tank when 



