Principle: dai gaw direct action hte pilot principles hpe kahkyin gumdin ai, n-gun atsam ngut ai hpang, shang wa ai hte pru ai shara lapran hta n-gun shai hkat ai lam n nga ai shaloi, electromagnetic n-gun gaw pilot valve kaji de hkrak sha n-gun hte main valve pat da ai daw ni hpe galai shai wa ai, valve hpe hpaw dat ai.
N-gun shai hkat ai lam hpe hpang na matu shang wa ai hte pru wa ai shaloi, power ngut ai hpang, electromagnetic force pilot valve kaji, main valve a npu na chamber pressure rawt wa ai, ntsa na chamber pressure gaw hkrat sum mat ai, dai hku nna press shai hkat ai lam hpe jai lang nna main valve hpe ntsa de gang shadut na matu; Power off byin mat ai shaloi, pilot valve gaw, htum ai daw hpe gang je kau na matu, spring force (sh) medium pressure hpe lang nna, lawu de shamu shamawt ai, valve hpe pat kau na matu.
