The pilot valve recuates the outlet nressure of the main valve The outlet pressure does not change due to the change of the inlet nressurand the inlet fow The outlet pressure does not change due to the change ofthe import pressure and the import fiow rateand the outlet pressure is maintained at the set value safely and reliably, and the set value can be adjusted according tothe situation. The valve has the advantages of accurate decompression, safety and reliability, convenient installation ancadiustment, and long service life.