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Square Body LoPro
Square Body LoPro
Square Body LoPro
Square Body LoPro
Square Body LoPro
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7.3.2 O-Ring Replacement
The bonnet o-rings may easily be removed without special fixture. With a
little stretch, the bonnet o-ring clears the bellows and drops off of the
actuator assembly.
Removal of the nosepiece o-ring usually requires a thin tool to pry it out of
its trapezoidal groove. Exercise care to avoid damaging the sealing surface
at the bottom of the groove. Start prying at the vent hole and carefully move
around far enough to allow grasping the seal with the fingers. Then pull the
seal from the remainder of the groove.
Be sure that no dust or other contamination is in the groove or on the o-ring.
To install the o-ring, nest the o-ring on the opening of the groove. With the
thumbs at points 180
o
apart, firmly press the o-ring into the groove. Move
90
o
and press again. Move 45
o
and press again. Alternately press the o-ring
into the groove until it is completely in the groove. Hand installation will
likely leave humps on the installed o-ring. As long as the o-ring has not
twisted during assembly, this will disappear after a small number of cycles,
after which the valve should function properly.
7.3.3 Actuator Assembly Installation
Before installing the actuator assembly, turn the manual knob so that the
assembly is not in the bottomed out position. Insert the actuator
assembly into the valve body. As with removal, take care to avoid
damaging the bellows. Be sure that the bonnet o-ring is in place. The
bellows flange is appropriately tapered to aid in retaining the o-ring in the
proper position during assembly. Insert the four bolts and tighten the
actuator to the valve body.
The actuator assembly is completely installed when the bottom of the
actuator is flush to the top of the valve body and the four attaching bolts are
tight. [Torque on bolts » 45-50 in. Lb. (5.0 Nm)]
It is highly recommended to check the assembly for leaks using a high
quality Helium mass spectrometer leak detector. The vent slot inbetween
the acuator cap and the bonnet flange is used for leak detection. With the
interior of the valve evacuated and attached to the He mass spectrometer,
insert the tracer gas probe into this slot. The bellows and bonnet seal are
accessed for leak detection through this slot. The nosepiece seal and port
flange seals may be tested through a variety of methods and will not be
detailed here.
Summary of Contents for HPS LPV1-25-AC Series
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