Flowserve 1888 Parallel Slide Gate Valve User Manual
Page 9
(b)
Check the seating surfaces to determine that scratches or
minor imperfections do not exist on the discs or seat rings. If
any are evident, lap these surfaces until none are visible.
(Reference Para. 9.3.)
(c)
Insert the stem (025) into the “T” slot in the disc carrier (178).
The disc carrier (178), spring (269), and discs (004) can now
be positioned onto the stem. As the stem and disc pack are
lowered into the valve body, they should be contained to
reduce the possibility of falling and becoming damaged.
(d)
Once the stem / disc pack assembly is positioned into place,
the bonnet (002) can be lowered into the body neck. Care
must be taken in lowering the bonnet onto the stem to prevent
possible scoring.
(e)
With the bonnet resting inside the body neck, a new pressure
seal gasket (030) can be inserted. Because of tolerances
are close and the gasket may cock, it must be inserted with
care.
(f)
Thread the gasket retainer (033) into the body; tighten to the
bottom of the threads and back out enough to align the
packing gland bolts onto the valve body. With the gasket
retainer in the proper position, the gland retainer (131) can be
lowered over the stem and threaded onto the bonnet (002).
The bonnet will be raised squarely until it is firmly in contact
with the pressure seal gasket.
(g)
Note that it is not necessary to torque the gland retainer. The
bonnet is truly sealed by pressure. The only function of the
retainer is to hold the bonnet in contact with the gasket until it
is deformed by pressure, locking the joint together and
insuring a tight seal. Since the bonnet is sealed by pressure,
constant cycling may compress the gasket and necessitate
tightening of the gland retainer setscrews.
(h)
Once the bonnet is in the proper position, the gland retainer
may require backing off to align the slots for the gland bolts.
Once this has been accomplished, the gland retainer
setscrews (220) should be installed and tightened.
(i)
Install the packing into the bonnet in accordance with Section
9.2.