CRANE. | Pumping Machinery. 307 
Most of the Cornish pumps are provided with these heads, 
but occasionally the upper or funnel-shaped portion is want- 
ing. 
THe Cotumn Pipn.—The column pipe may be made of 
wrought iron, with flanges riveted to or screwed on the ends, 
or, what is probably better, cast iron, with flanges cast with 
the pipe. Both kinds are, however, used. A rubber gasket, 
or aring, cut out of rubber belting, serves to make both an 
air- and water-tight connection between the two flanges. 
Pipes from eight to ten and twelve inches in diameter are 
used, while wooden pipes are occasionally employed, espe- 
cially for short lifts. 
THe Worxkinc Barret.—The working barrel consists 
of a short length of pipe (figure 81), generally seven to 
eight feet, and one inch less in diameter than the column 
pipe, which is to allow the working valve or wheel to be 
withdrawn. The barrel is either an extra-well-made piece of 
pipe, or is especially made, and often turned smooth and to 
an even diameter inside, or lined, to prevent too much fric- 
tion between the barrel and the moving valve; also to pre- 
vent leakage. The clack valve rests on top of the suction, 
which is fastened to the lower end of the working barrel. 
Cuack VAaLtvEs.—The forms of clack valve used are: First, 
a common form, consisting of a lid, hinged at one side, which 
is lifted by the rising currents of water on the up stroke and 
falls on the down stroke, closing the valve; another form is 
shown in figure 82, at Z, and consists of a disk or cap, which 
slides on a central pin, thus opening and closing the valve 
with the rise and fall of water. The vertical movement or 
play of the cap should be from 1% to 2 inches. 
A top view of the valve complete is shown at /, Z, a section 
at 2, Z, and a bottom view at 3, Z. The pin, X, is adjust- 
able, usually being keyed or fastened with a lock nut, so that 
the lift of the cap or lid, Y, may be varied. 
The advantage of this form of valve is that the discharge 
area is the same on all sides. 
THE SUCTION AND SLEEVE.—The suction consists of a 6-foot 
length of pipe, which is fastened to the lower end of the work- 
