48 



BULLETIN 906, U. S. DEPARTMENT OF AGRICULTURE. 



•-V.V. 



pig. 30.- 



-A distributing hydrant to reduce water pressure 

 on hillsides. 



type is that gates 

 must be regulated 

 very accurately 

 where a large num- 

 ber of orchard hy- 

 drants are fed simul- 

 taneously. As a rule 

 such construction is 

 best adapted to 

 grades that will al- 

 low enough orchard 

 hydrants between' 

 two successive 

 stands to take all 

 the water carried by 

 the pipe line. 



A third plan that 

 is also adaptable to 

 comparatively small pressures is to provide standpipes at intervals 

 high enough to back water from one to another (fig. 34). The stands 

 may be made of concrete pipe cemented together and set up verti- 

 cally. A slide gate is cemented to the discharge pipe at each stand, 

 leaving the inlet open. When the gate is closed, water will rise in 

 the stand until it is backed up to the one above it. If an excess of 

 water is turned in the pipe line, these stands will overflow and thus 

 relieve the pressure. This plan is advisable where the gate can 

 be easily manipu- 

 lated from the top 

 of the stands. If 

 the standpipe is too 

 high, it is possible to 

 install a gate valve 

 or irrigation valve 

 that is boxed in, 

 leaving the handle 

 of the gate to project 

 through a packing 

 box in the top. Some 

 companies have in- 

 stalled a short aux- 

 iliary stand imme- 

 diately below the 

 main standpipe. 



rillS Stand Contains f ig . 31.— Another type of hydrant shown in Fig. 30. 



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