Gate Valves Installation & Maintenance

Gate Valve Installation & Maintenance Instructions

Gate Valves of all materials and seat types are easy to use and long lasting when they are installed and maintained correctly. The installation technique varies slightly for different end connections (eg. flanged vs rolled groove vs victaulic) but the other instructions remain the same.

Storage Conditions 

• To protect the seat and seals do not unpack the valves until they are ready for installation. By doing this you are protecting the valve from dust and debris which may eventually cause seat leakage.

• Keep in a cool well ventilated space if storing for a longer period of time.

Valve Installation 

• Valves can be installed in any orientation however it is best if it can be installed upright especially in bigger sizes for ease of hand wheel access.
• Verify the material of the gate valve, seat and disc before installation. Ensure that there are no defects caused by storage or transportation.
• Complete all welding works before valve installation and be sure the flange has cooled to ambient temperature before installing the gate valve using the appropriate gasket.
• Make sure there is no welding residue, waste, rust, pickle paste or other debris in the pipe before installation. Wash with water or a mild detergent if needed.
• Make sure there is no warpage of the flange or misalignment of the gate valve in relation to the flange. This is the most common cause of valve problems where it is not aligned with the flange/pipe correctly. Support the valve where necessary to reduce load on the piping assembly.
• Install the spacing bolts taking care not to damage the valve seat and adjust the face to face of the two flanges so there is space when the piping is spread open (enough space to slip the valve in or out for service).
• Once the pipes are centered, insert the bolts so that the bottom of the valve can rest upon them to prevent the valve from falling through.
• Tighten the bolts one at a time doing it in stages so even pressure is applied and a seal is formed between the valve, gasket and flanges.
• Once the installatiion is complete, operate the valve several times to ensure it has not moved during installation.

Field Testing 

• Rubber seated gate valves are designed to hold rated pressures only. Test pressures above rated working pressure in the closed position can cause damage to the valve.
• With the valve in the open position the pipeline can be tested up to the valve hydrostatic test pressure.
• Seat leakage can occur when foreign material is wedged between the seat and the body. If this occurs, open the valve 10% to 15% to obtain high velocity flushing action. Close and repeat if necessary.

Operation 

• Do not use the valve at pressures above its working pressure.
• If the valve is jammed in a position between open and closed check the valve face and seat. Remove and check for foreign objects (see maintenance).
• Excessive torque from actuators can damage internal valve parts.

Maintenance 

• Cycle the valve at least once a month if not used regularly.
• Relieve the system pressure before performing any maintenance.
• To remove from pipework reverse the installation sequence (above).
• Replace valve gate by removing the top body (bonnet) and stem. Screw out the gate and replace with new part. Install top of body and refit into line.
• See video link under each gate valve model for further instructions.

Design Guidance and Product Advantages 

• When sizing the valve always consider available space for handwheel operation.
• Consider valve supports to carry excess weight.
• Extensions shafts in 316 Stainless Steel are available upon request. This will allow for the valve to be mounted in a pit with above ground operation.
• These valves have Ductile Iron bodies for added strength. High finish moulded seats give low torque operation for long maintenance free working life.