Flowserve Cast Flex Wedge Gate Valve Manuel d'utilisateur télécharger pdf (Page 25)

Cast Flex Wedge Gate Valves FCD ADENIM0010-02

6.0 DISASSEMBLY (Continued)

6.3.2 Bonnet: (Figs. 16 & 17)

The following instructions assume the yoke has been removed as explained above.

a. Unbolt the gland nuts (234) and remove the gland flange (130) and gland (107). Put them in a safe place and

thread the nuts back on the gland studs to prevent loss. Remove the packing.

b. Unbolt the capscrews (bonnet) (216) and remove the retaining ring (bonnet) (034). Set aside for use later.

c. Tap the bonnet sharply to break the seal between it and the pressure seal gasket (030). The bonnet will drop

downward against its stop, uncovering the retaining ring (gasket) (033).

d. The retaining ring (gasket) (033) is comprised of four segments, one of which has a small drilled hole. Remove this

piece first. The groove in the top of the retaining ring gasket permits the use of a pry bar or screwdriver in removing

the segments. In some cases, it may be necessary to loosen the segments by tapping with a hammer or bar.

e. The bonnet is now ready for removal from the body. The tight clearances between the body bonnet and gasket,

necessary for a reliable seal, require that the bonnet be withdrawn squarely from the neck bore. The slightest cocking

of the bonnet during withdrawal can cause it to bind. Therefore, it is recommended prior to removal, that the

squareness of bonnet and gasket with respect to the body be checked. This is most easily accomplished by

measuring the distance between the top of the gasket and top of the body neck. If the gasket is not square, it should

be tapped with a brass rod until it is. With large bonnets, it is a good idea as well, to periodically check the

squareness of bonnet as it is being withdrawn. Binding any time during withdrawal indicates the bonnet has cocked.

Further efforts to force the bonnet will generally make the situation worse. At the first sign of binding, stop and check

the squareness of the bonnet.

Figure 16 Figure 17

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Flowserve Cast Flex Wedge Gate Valve Manuel d'utilisateur Page 25