Western Electric 407A-4, Инструкция по эксплуатации

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Crack R . H. valve and bleed air from top of R. H. vapor
trap . Close R. H. bleeder and R. H. valve .
Zero Adjus tment
Close all three valves on instrument manifold, circulate
water through the venturi .
Open center valve very slightly.
Crack L. H. valve unt il indicator shows approximately 5
to 10 per cent of full s cale .
Slowly clos e
(
not completely
)
center valve to caus e in­
dicator to rise to full s cale . Open c enter valve sufficient­
ly to allow indicator to return to z ero . Manipulate center
valve so that indicator sweeps from z ero to fu ll s cale
several times . This will s ettle the mercury in the instru­
ment . Clos e L . H. valve and open center valve . If indicator
returns below zero, there is t oo much mercury in instrument.
Carefully and slowly withdraw mer cury through needle drain
at the bottom of loop below the two chambers of the instru­
ment . See Fig. 10. Withdraw only enough mercury to cause
the indicator to move to z ero .
If indicator rests above z ero , there is not enough
mercury in chambers . Stop fl O\M of water through venturi and
drain that line . Drain mercury and water through bottom
valve, opening side valves and top bleeders to allow com­
plete drainage . Repeat operation of filling chambers with
mercury and water as described above .
To
Put
Meter in
S lowly open, in sequenc e mentione d, L.H. valve and
R . H. valve in instrument manifold. Close center valve .
The instrument is then in operati on.
To Put Meter Out of
S lowly close, in sequence mentione d, L.H. valve and
R.H. valve . Open center valve.
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