42 BULLETIX S&4, U. S. DEPARTMENT OF AGRICULTURE. 
Table 8. — Capacity of drain pipe of various sizes based on a slope of 1 inch in 10 feet. 
Gallons Required 
per I diameter 
minute. in inches. 
50 
75 
100 
150 
200 
Increasing the slope increases the capacity. The graduation of 
drain pipe sizes to accommodate drainage from a battery of kilns 
may be figured according to general suggestions under "Size of 
PUMPS. 
The pump found to be most suitable for dry-kiln work isjthe direct- 
acting boiler-feed type, duplex-piston pattern, bronze or brass fitted 
with brass-lined cylinder, water pistons submerged, and composition 
valves. The piston should be packed with a high grade hot water 
packing. 
Pumps should be set in accordance with manufacturer's instructions 
and the hot well pump should be below the level of the water in the 
hot well to obviate loss of priming. No reductions should be made 
in the size of the inlet or outlet connections. Sufficient working space- 
should be allowed around the pump to permit the operator to oil 
and overhaul it without danger while it is in motion. 
The suction pipe should be as short and direct as possible and 
fitted with a foot valve and box strainer at the intake. 
Each pump should be equipped with a pump governor to regulate 
the discharge of water from the pump in accordance with the demand 
of the water mixer, the pressure in this way being kept balanced 
with that in the cold water main held by the pressure-regulating 
valve. A pressure gauge of the Bourdon type should be placed on 
the discharge, in a convenient place for observation. 
The discharge from each pump should be equipped with a self- 
cleaning strainer of the pot type, the full size of the discharge pipe 
and designed to withstand full pressure. Such a strainer should be 
provided with a drip connection to sewer, properly valved so that 
dirt and sediment can be removed from time to time. A by-pass and 
valves around strainer should be provided in order that the strainer 
may be removed for repairs if necessary without shutting down the 
kilns. 
The pumps should be equipped with a sight-feed mechanically 
forced oil lubricator. 
If the exhaust steam from the pumps is to be used in the heating 
coils the exhaust from all pumps should unite into a common 
exhaust main discharge, through an oil separator, and into the low 
