CONSTRUCTION AND WORKING PRINCIPLES
The VQ400 combination gas valves are 2 x class "A" fail
safe shut--off valves.
The valve is opened by energizing the direct ON/OFF
The direct ON/OFF operator consists of a coil and stop sleeve
assy. Inside the top sleeve assy is a plunger which is able to
move up and down and thus opening or closing the valve.
flow rate adjustment nut
Fig. 11. Construction drawing VQ420/425
The plunger is gliding on two anti--friction bearings.
Flow regulation is done by adjustable plunger stroke.
A strainer made out of steel AISI 303 is incorporated between
inlet flange and main body.
Valve closing spring is made out of steel AISI 302.
Seals and gaskets are manufactured out of hydrocarbon
resistant NBR according to DIN 3535 and EN291.
gas flow direction