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Unloader Mechanism


The mechanism is operated by oil pressure  from  the  capacity  control  valve.  The  oil pressure pushes the unloader spring against the unloader piston. This action moves the unloader rod to the left,thereby  rotating  the  cam  rings.  As  the  cam  rings  arerotated, the lifting pins are forced upward, raising thesuction valve off its seat. The suction valve is held in this  position  until  the  compressor  is  started  and  oil pressure of approximately 30 psi is reached. At that time,the oil pressure from the capacity control valve pushesthe unloader piston back to the right against the unloader spring.  The  motion  transmitted  through  the  push rod rotates  the  cam  ring.  This  lowers  the  lifting  pins  and allows the suction valve to close or operate normally and the  cylinder  to  become  loaded  .
 

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