the riser of 14-inch pipe, which | 
will make a strong support x | 
even if this is larger than the 
first section of nozzle line. An 

_ into the opposite side of the 7 
SPRAY IRRIGATION. 23 
The chief advantage in the suspension system is the reduction of 
obstruction in the field, and where it is well constructed the plant will 
be very durable. This type costs more than the others and is not as 
commonly used as the simple post supports., The cleaning of nozzles 
en highly supported lines is difficult, so pipe should be kept within 
reach. 
NOZZLE LINES. 
The pipe in the nozzle lines should be galvanized wrought iron or 
steel. The galvanizing not only makes the system longer lived, but 
reduces oxidation of the metal, which, if not prevented, tends to form 
scales that fill the nozzles. — 
A nozzle line is connected with the main feed pipe by means of a 
riser cut the proper length to act as the first post in the line. In the 
longer lines it is well to have 7 


elbow is placed on top of the | | 
riser, and into this is screwed 
a long nipple which terminates 
in a standard brass gate valve heme ea ee 
(ip 12)" Vo reduce friction 27.30 (eo 
“i \ \: Tus 
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this valve should be of the Ys 3 Yj Yj y iY 
same size as the. standpipe. c 27/ —Y A Vy DO 
The turning union is screwed i L 
mua 
valve. The union most com- Fic. 15.—Anchorage for suspended overhead 
monly used contains 4 sereen nozzle lines, showing location of ‘ dead- 
aig é man’ and turnbuckles. 
for catching sediment from the = 
passing water. A capped handle 2 feet long, made of 2-inch pipe, is 
screwed into the side of the union. This serves as a lever for turn- 
ing the nozzle line in its bearing as well as giving entrance to the 
union for flushing the screen. 
Reducing couplings, and not bushings, should be used for connect- 
ing the different pipe sizes. A 3-inch valve or a cap should be placed 
over the extreme end of the nozzle line. This permits flushing out 
the line at any time by opening the valve or removing the cap. 
(See fig. 13.) 
MAIN FEED PIPEs. 
There are several kinds of pipe adaptable for spray irrigation 
mains—steel or wrought iron with threaded joints, riveted steel with 
flanged or bolted joints, cast iron with lead or bolted joints, and wood- 
| stave pipe. 


