232 



HANDBOOK OF MECHANICAL DESIGN 



Supply 



Piloi- 

 arcu/^ 



J fxhausi- 

 i- Delivery 



Pilot 

 circuif 



Exhousi 



J Delivery 



First Condition Second Condition 



Fig. 470. — Single three-way solenoid valve cuts off supply and vents delivery through exhaust. Application similar 



to that, shown in Fig. 466, using two straight-way valves. 



Pllof 

 circuif 



rrrr\j(Load k> be 

 VtSlifMby 

 piston 



Supply 



Three-v^ay 

 valve 



Pilot . 

 circuif 



Down 



Supply 



Operating ^_»- _ 

 cylinder ' " 



Second Condition 



Operating 

 cylinder 

 First Condition 



Fig. 471. — Three-way valve provides convenient means of controlling single-acting cylinders or diaphragms. By 

 utilizing principle shown in Fig. 470, valve cuts off supply and vents delivery through exhaust, thus permitting return 

 stroke of piston to take place. 



Pilot ^ 

 circuit 



Supply 



First Condition Second Condition 



Fig. 472.— Three-way valve arranged for multiple control of pressure-operated valves. In the first condition 

 valve A is closed and valve B open. In the second condition, the reverse is true, with valve A open and valve n 

 closed. 



