Evoqua WALLACE & TIERNAN S10k, Instruction Manual

Page: 19 / 104

S10k
Description
3.
19
3.3.2 Heater (optional)
An optional heater unit (W3T162239) is available for installations
where reliquefaction of the gas within the valve is a problem due
to low external temperatures. Reliquefaction can occur if the tem-
perature in the vacuum demand valve is below the temperature in
the gas cylinder.
This unit comprises a bolt on capsule which attaches to the check
valve housing of the vacuum demand valve. The thermostatatical-
ly controlled heater is designed to operate on any single phase
supply of 115 volts or over, up to a maximum of 230 volts.
Electric connections must be made by electric specialists accor-
ding to the corresponding rules, e.g. EN 60204.
The LED on the unit is on when the unit is under tension.
The unit can be hot (ca. 60°C).
3.3.3 Pressure relief valve
The pressure relief valve fits into a recess in the back housing of
the regulating valve. The relief valve comprises a spring, stem and
diaphragm. The face of the diaphragm is spring loaded against two
openings, one opening connects into the main chamber of the val-
ve and the other connects to the vent line. Should either of the
check valve stems fail to seat when the operating vacuum is shut
off, gas will pass into the main chamber of the valve where its pres-
sure acts against the underside of relief valve diaphragm. The re-
lief valve diaphragm is forced against its spring until it unseats at
which point gas is allowed to pass to atmosphere via the vent line.
3.3.4 Flowmeter assembly
The flowmeter assembly is fitted with a graduated glass tube and
a control knob. The tubes inner surface is tapered towards the bot-
tom and contains a free moving float. The gas forces the float up
the tube until it can flow round it thus indicating gas flow by the po-
sition of the float in relation to the graduations. The control knob
screws a variable orifice V-notch plug in or out to adjust the volume
of gas passing through the assembly.
Mounted heater unit