WOOD PIPE FOR CONVEYING IRRIGATION WATER. 



17 



metal, thus leaving it subject to decay. It is considered better prac- 

 tice to insert the wood pipe into the metal pipe and calk with lead 

 and oakum. To do this usually requires a special coupling either of 

 cast iron or steel. An example of a cast fitting illustrating this 

 method of joining wood pipe and cast-iron pipe is shown by figure 



5, and another of steel for uniting wood pipe and steel pipe by figure 



6. An important fea- 

 ture in both of these 

 designs is the thim- 

 ble or flange which 

 fits inside the wood 

 staves to prevent 

 them from being 

 forced in by the 

 calking. 



If continuous 

 stave pipes are built 

 above ground it is 

 usually best to sup- 

 port them in. " cra- 

 dles " or " chairs." 

 In the design and 

 spacing of supports 

 of this kind the ideas 

 and judgment of en- 

 gineers differ and as 

 yet there is no stand- 

 ard practice. 



Cradles of the 

 general type shown 

 by figure 7, A, were 

 used on several large 

 pipe lines of the 

 Kings Hill irriga- 

 tion system in Idaho, 

 and they appear to 

 be well designed. 



On some pipe lines the 2 by 12 inch mudsills are continuous; on 

 others, blocks 18 inches long are used. The use of short blocks in 

 this way is more economical of material, and requires less grading. 

 The cradles of the type shown by Plate IV, figure 1, were spaced 6 

 feet center to center under a 54-inch pipe, and to support a pipe 100 

 inches in diameter cradles of the same type of 8 by 8 inch material 



61133°— Bull. 155—14 3 



gad Btft Circle 43 



K- 



