Valve controlling gas flow to burner - has expansion chamber between valve seat and outlet nozzle to reduce pressure dop

摘要

The solenoid (9) actuates the plunger (6) which lifts the pad (5) off the valve seat (4) in the valve body (2) which is provided with an inlet (1). The bore of the outlet below the valve seat (4) enlarges from a diameter (D) to a diameter (Dc) and is then reduced to a diameter (d) through the nozzle (15). The ratio of the diameter (D) to the diameter (d) lies between 1.8 and 2.2 whilst the ratio of the diameter (Dc) to the diameter (d) lies between 3.8 and 4.2 and the length (1) is between 7.5 and 8.5 times as great as the diameter (d). These proportions result in a very low pressure drop through the valve and a discharge co-efficient of almost 1.0 for the nozzle (15) and so maintains a constant gas to air ratio to the burner.