3.3. 2 Extension stem disassembly
3.3.2.1 Remove the bolts between gearbox and top flange of the protection tube.
3.3.2.2 Remove the gearbox.
3.3.2.3 Remove the bolts between flange of the protection tube and valve top flange
3.3.2.4 Remove the protection tube.
3.3.2.5 Remove the extension stem and key (If have).
3.3.2.5 If there are two pieces or more extension stem, remove the bolts between two flanges of the protection
tube.
3.3.2.6 Remove the protection tube.
3.3.2.7 Remove the extension stem and connector. Repeat 3.3.2.5 to 3.3.2.7 until remove the extension stem from
the valve bare stem
3.3. 3 Importance Notice.
To check if the matching flange surface in good status, no trash in the wedge, no damage during the delivery, and
the pipeline is already clear.
3.3.3.1 Ensure the distance between end flanges of two pipelines enough for installation.
3.3.3.2 Ensure the seats and the flanges are clean when installing the gate valve.
3.3.3.3 Select the correct type of gasket. Gaskets with the correct flange size must be used.
3.3.3.4 When valves are provided with lifting lugs, plates or eye nuts, there must be used to lift the valve.
3.3.3.5 Place valves between pipe flanges and insert the bolts..
3.3.3.6 Tighten the bolt loosely..
3.3.3.7 Tighten the bolt in diagonal sequence to make sure flanges are pulled parallel.
3.3.3.8 To fasten the bolts in cross direction with proper torque.
4 Operation
General
The gate valve is suitable for use with water or neutral liquids from 0°C to 80°C. Insulation is essential for external
temperature from 0°C to -10°C. The gate valve can be operated by either hand wheel, gearbox or electrical
actuator.
4.1 Operation Direction
4.1.1 Valve closing: Operate the stem in clockwise direction.
4.1.2 Valve opening: Operate the stem in counter clockwise direction.
4.2 Possible risk:
4.2.1 Mechanical: If operate the valve manually, ensure there is enough space to operate the valve to avoid hand
clamping.
4.2.2 Electric: Since the static electricity could cause the explosion, the valve should be ground connection.
4.2.3 Temperature: If the outside temperature is below 5 ℃ or above 40 ℃, the valve surface will be very cold or
hot, should take shield to protect the internal components of the valve, like O-ring, rubber kits, etc. People who
operate the valve should be with protection.
4.2.4 Operational: If close the valve too fast, there will be water hammer come from the upstream. And the the
water hammer may damage the valve. In any case, should avoid the water hammer.
5
