Large diameter ball valves are commonly used in industries such as petroleum and chemical processing, power generation, long-distance pipeline transportation, and large-scale water treatment systems. If installation is not performed correctly, it may lead to sealing leakage, valve jamming, or structural stress damage. Therefore, proper installation practices are essential to ensure long-term stable operation.
If pre-installation inspection is insufficient, operational failures are more likely to occur during service. First, inspect the valve body for transportation damage. If scratches, impact marks, or deformation are found on the valve body or sealing surfaces, installation should be stopped and the supplier should be contacted.
Next, verify valve model, pressure rating, and connection standards. If the system design pressure does not match the valve pressure class, operational safety risks may occur. For example, if a low-pressure class valve is mistakenly used in a high-pressure pipeline system, the valve body may experience plastic deformation under water hammer impact.
It is also necessary to check the condition of the ball surface and sealing rings. If there are scratches on the ball surface, sealing performance will be reduced. This is especially critical in gas transmission systems where micro-leakage is more likely.
Large diameter ball valves usually have a flow direction marking. If the installation direction is incorrect, the following problems may occur:
If the fluid flow direction matches the design direction, the operating torque will remain more stable. If the valve is installed in reverse, the stem may experience increased mechanical load, which will accelerate stem wear during long-term operation.
For double-seal bidirectional ball valves, although bidirectional flow is allowed, installation according to the marked flow direction is still recommended to ensure more uniform sealing stress distribution.
In high-temperature or steam systems, if the installation direction is incorrect, thermal expansion may accelerate sealing ring aging.
Large diameter ball valves are heavy. If installed without proper support, additional bending moments may be transferred to flange connections.
If pipeline systems experience axial displacement, pipeline supports should be installed for segmented fixation. If support structures are not provided, the valve body may bear long-term gravitational tensile load, eventually causing flange seal failure.
It is generally recommended to install independent supports on both sides of large diameter ball valves. If the pipeline system is subject to thermal expansion and contraction, expansion compensation devices must be installed; otherwise, sealing surfaces may gradually fail.
Flange connections of large diameter ball valves usually require stepwise bolt tightening.
If bolts are fully tightened in a single step, uneven flange stress distribution may occur, causing gasket compression damage. It is recommended to use a cross-pattern tightening sequence and apply torque in 2–3 gradual tightening stages.
If spiral wound gaskets are used, torque uniformity must be controlled; otherwise, initial micro-leakage may occur.
Lubrication of bolt threads is also important. If threads are not lubricated, torque loss may increase and actual preload force may be insufficient.
Large diameter ball valves are not recommended to be opened or closed too quickly.
If the valve is opened suddenly, the pipeline fluid may generate instantaneous velocity shock. If the system contains gas-liquid two-phase flow, water hammer effects may be more severe.
During commissioning, it is recommended to conduct low-opening test operation first. If operation remains stable, gradually increase valve opening to the design working condition.
If the system operates under high differential pressure, staged opening and closing operations are recommended to reduce sealing surface impact wear.
Regular inspection is recommended for large diameter ball valves.
If leakage is observed at the stem sealing area, packing seals should be replaced in time.
If operating torque increases significantly, this may indicate insufficient lubrication or wear of sealing pairs.
If the valve remains in fully open or fully closed position for long periods, periodic small-range operation is recommended to prevent ball surface sticking to sealing rings.
In pipeline systems containing solid particles, regular flushing is required. Otherwise, contaminants may accelerate sealing surface wear.
If improper lifting tools are used, the valve body may deform due to uneven force distribution.
If the valve is used as a pipeline support point, additional structural stress may damage the valve body.
If the installation environment contains heavy dust without protection, sealing life will be significantly reduced.
Large diameter ball valves are heavy-duty industrial valves. Wild or improper installation practices must be avoided.
Q: Is flange support mandatory for large diameter ball valve installation?
A: If the valve weight exceeds the pipeline load-bearing capacity, additional flange support structures are required to prevent sealing misalignment.
Q: Can large diameter ball valves be installed vertically?
A: For floating ball structures, vertical installation is generally not recommended. For trunnion-mounted ball valves, vertical installation is possible if pipeline support conditions are satisfied.
Q: How long should the valve wait before commissioning after installation?
A: For normal temperature water systems, trial operation can start after tightening and inspection. For high-temperature or high-pressure systems, low-load preheating operation is recommended first.
Q: Why do large diameter ball valves tend to have higher operating torque?
A: Because larger ball diameters increase sealing contact area, resulting in higher sealing preload force and higher operating torque requirements.
Copyright © 2015-2026 DERVOS VALVE CO.,LTD.All Rights Reserved Blog / Sitemap / XML / Privacy Policy
