I. Definition of a cryogenic Globe Valve
A cryogenic globe valve is a force-sealed valve that ensures tight closure by applying pressure to the disc when shut. When open, the disc typically lifts 25%-50% of the nominal diameter, with maximum flow achieved at 30% lift (indicating full-open position). The full-open status is precisely controlled by the disc's travel.
II. Installation Key Points for Cryogenic Globe Valves
a) Support Requirements: Avoid subjecting the valve to pipeline weight. Large valves should be independently supported to prevent deformation or damage from system pressure.
b) Flow Direction: Align the medium flow with the arrow mark on the valve body for proper operation.
c) Orientation: Install vertically to ensure sealing performance and operational flexibility.
III. Working Principle
The valve's plug-shaped disc (with planar/conical sealing surfaces) moves linearly along the fluid centerline via a threaded stem. Pressure from the stem forces the disc against the seat to block flow.
IV. Common Issues & Solutions
① Damaged Sealing Surfaces
Cause: Residual welding slag or contaminants in unflushed pipelines.
Solution: Flush pipelines pre-commissioning and install filters.
② Internal Leakage
Cause: Damaged seals or embedded impurities.
Solution: Repair seals and clean thoroughly.
③ External Leakage
Cause: Seal failure, loose connections, or improper operation.
Solution: Regularly inspect seals, tighten connections, and follow protocols.
④ Additional Challenges:
Frequent cycling wears packing; cryogenic contraction occurs.
Solutions: Tighten packing nuts or replace damaged seals.
V. Installation, Operation & Maintenance Guide
Storage: Keep in dry conditions; handle gently to avoid contamination or surface damage.
Welding: Leave valves open during welding to prevent heat damage to seals.
Post-Welding: Purge pipelines with dry, oil-free gas to remove slag.