1. Pre-installation Preparation
1.1 Inspect the valve and verify service conditions
Unpack the valve and carefully verify that the service conditions conform to the marking specifications. Check that the valve operates normally and inspect the sealing surfaces for scratches or other damage.
1.2 Prepare accessories and tools
Prepare accessories such as gaskets, bolts, nuts, plain washers and spring lock washers of matching nominal diameter, together with the installation tools.
2. Installation Procedures and Precautions、
Step 1: Allow sufficient clearance
Reserve a proper pipe end clearance.
Step 2: Position and align the valve
Place the valve between the pipe ends and align it with one end of the pipeline. Align the flange holes of the pipeline with those of the valve.
Step 3: Insert the gasket and fit the fasteners
Put the gasket between the valve and the pipeline at the aligned end. Fit the prepared bolts, nuts and gaskets of matching specifications into the flange holes.
Step 4: Tighten the first flange connection
Tighten all nuts evenly in a crisscross sequence.
Step 5: Connect the other end
Put the gasket between the valve and the pipeline at the other end, and insert the prepared bolts of matching specifications into the flange holes.
Step 6: Tighten the second flange connection
Tighten all nuts evenly in a crisscross sequence.
3. Notes on Installation and Commissioning
3.1 Valve orientation and piping alignment
Position the valve prior to pipeline installation. For horizontal pipelines, the valve handwheel shall face upward.
Piping shall be fitted naturally. Do not force the piping into alignment, as this may introduce residual pre-stress.
3.2 Flange alignment and fastener assembly
The perpendicularity of the piping flange face relative to the pipeline centerline and the tolerance of the flange bolt holes shall be within allowable limits.
Align the centerlines of the valve and pipeline.
Place the gasket between the two flanges and ensure that it is not offset.
Insert bolts through both flanges, then fit plain washers, spring lock washers and nuts in sequence. Tighten the nuts manually.
Install all bolts and nuts in this manner.
3.3 Final tightening and inspection
Use a wrench that matches the nut size when tightening.
If hydraulic or pneumatic tools are used, do not exceed the specified torque.
Avoid uneven force during flange tightening. Tighten in a symmetrical, crisscross sequence.
After flange installation, verify that all bolts and nuts are uniformly tightened.
Q1. Why is my resilient seated gate valve leaking when fully closed?
Leakage when closed may be caused by trapped debris, worn sealing surfaces or insufficient closing torque. Check the following:
Trapped debris: Flush the valve to remove dirt between the gate and seat sealing surfaces.
Damaged or worn sealing surfaces: Inspect the gate for damage or wear from long-term service and replace it if needed.
Insufficient closing torque: Increase the closing torque as appropriate, within the manufacturer’s specified limits.
Q2. How do I fix leakage between the gate valve body and bonnet?
Leakage at the body-to-bonnet joint may result from loose bolts, damage to the flange sealing surface or a damaged gasket.
Loose bolts: Tighten the body-to-bonnet fastening bolts.
Damaged flange sealing surface: Inspect for grooves, scoring or other damage and repair the affected surface.
Damaged gasket: Replace the gasket with a new one.
Q3. Why is my resilient seated gate valve hard to open or close?
Stiff valve stem operation may be caused by damaged threads, foreign matter around the threads or a damaged OXQ component.
Damaged stem or stem nut threads: Inspect and repair the mating threads.
Foreign matter around the threads: Disassemble the affected components and clean the stem and stem nut threads.
Damaged OXQ component: Replace the damaged OXQ.
