DRIVES AND CONTROLS 



231 



C 



m 



ELECTRICALLY OPERATED VALVES 



-o/ o- 



L 



■ Power 



■ lines 



Corrfrol swiVch 



U Ex.hausi 



Tank 

 supply 



Supply 



Fig. 464. — Straight-way solenoid valve as eoin- 

 monly connected for simple fluid control. Control 

 switch energizes solenoid, opening valve, and per- 

 mitting flow to begin. 



S 



^ 



Floal, 

 swilch 



D 



■ Power 



■ lines 



Tank level'' 



Fig. 465. — Straight-way valve applied to control 

 automatically liquid level. Float switch used as pilot 

 control device for valve. 



W 



K 



-Pilol 

 -circuil- 



m 



ExhausI 



li Delivery 



Supply 



First Condi+ion 

 A-open, B-closed 



Fig. 466. — Two straight-way valves, A normally 

 open and B normally closed, provide two-way fluid 

 control. Energizing the solenoids cuts off supply 

 and vents delivery through exhaust. 



Power 



lines 



Wafer 



Fig. 467. — Two straight- way valves offer means of 

 automatically controlling cycle of processing machine, 

 such as plastic molding press, having heating and 

 cooling coils. 



Compressor 



Mofor lines 



Fig. 468. — Single straight-way valve can be con- 

 nected across one phase of motor winding to start 

 flow of cooling water to compressor whenever motor 

 starts. 



■ Pilol 



■ circuil 



Pump 



mA 



_ Furnace 



Oil supply 



Fig. 469. — Straight-way valve of trip type inter- 

 locked with oil-furnace control system to cut off oil 

 supply upon loss of current to motor-driven pump or 

 to atomizing equipment, or upon occurrence of low 

 water, low stack temperature, or similar conditions. 



