Control valve for water heater gas supply - contains differential pressure membrane utilising magnetic force to ensure rapid opening at threshold pressure

摘要

The valve comprises upper and lower shells between which is a differential pressure membrane defining two chambers. A disc on the upper surface provides rigidity and acts on a shaft for a gas inlet valve which is normally closed by a spring. The differential pressure created by a water pump is fed by small connecting tubes to act on the membrane. An adjusting screw in the lower shell opposite the shaft is sealed by a ring and supports a magnetic disc fixed to a base. This attracts a magnetic disc of the lower surface of the membrane until a threshold value of differential pressure is achieved when the membrane moves rapidly to open the gas inlet valve. This allows all sections of the burner to ignite the gas.