Flowserve Cast Flex Wedge Gate Valve - Manual (Page 29)

Cast Flex Wedge Gate Valves FCD ADENIM0010-02
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7.0 ASSEMBLY
(Continued)
7.2 Pressure Seal Bonnet Valves
7.2.1 Disc - Stem Assembly
The procedure for assembling the disc to the stem in a pressure seal valve is identical to the one for flanged
bonnet valves included in section 7.1.1. Refer to it for instructions.
7.2.2 Bonnet
Once the stem-disc assembly is in place the bonnet (002) can be inserted into the neck. Care must be
taken in lowering the bonnet on the stem, so that neither the backseat nor any surface of the stem is
damaged. It is again very important to keep the bonnet from cocking as it is lowered into the body. If it does
bind, the bonnet must be straightened before insertion can continue. Measuring from the bonnet bolting
surface to the top of body is the simplest way to detect cocking. With the bonnet resting on the counterbore
in the neck, a new gasket (030) and the spacer ring (032) can be inserted. In that the gasket may also cock,
it must be inserted with care. Once these are in place, the four-piece gasket retainer (033) can be put into
place. It is important to remember that the piece with the drilled hole must be positioned last. If the valve is
installed in other than a stem vertical position, it may be necessary to orient or hold the retainer such that the
pieces stay in place until the bonnet is moved into its raised position. With the gasket retainer in its proper
position, the bonnet retainer (034) can be lowered over the stem and placed in its position on top of the body
neck. The bonnet should be brought to the fully raised position and held (either by hand or a hoist
depending on the size) until the capscrews can be threaded into their holes in the bonnet. Note that cocking
must be avoided in raising the bonnet. If the bonnet binds before it is fully raised, it should be checked for
squareness. Note that while the capscrews need not be torqued to a specific value to maintain a tight seal at
system pressures, they should be tightened with wrench to insure good gasket-body-bonnet seal contact
before the full pressure is reached.
7.2.3 Yoke
The same procedure detailed in 7.1.3 for flanged bonnet valves should be followed. However, with pressure
seal valves the yoke attachment interface is different. The following steps should be substituted accordingly.
With yoke in its proper position on the body neck, the halves of the yoke clamp (012) should easily fit over
the mating lips on the yoke and the body. The yoke clamp studs (204) can then be inserted, and the nuts
(233) threaded on and tightened.
7.3 ACTUATORS
7.3.1 Manual
Reassembly of both gear actuators and handwheels can be accomplished by reversing the instructions
provided in section 6.1.1.
7.3.2 Motor And Air Cylinder
Instructions pertaining to the assembly of specific power actuators are included in supplements to this
manual.