Operation and Maintenance Manuals for Gate Valves

1. General 
These serials Gate Valves are used in the pipe system to close or open the pipeline to keep system running normally.
2. Product descriptions
2.1 These serials valve are hand-driven, through handle. The valve closes when turning the hand wheel clockwise and the valve opens when turning counter clockwise.
2.2 These serials valve are designed in according with  API  600 & API  6D specification etc.
2.3 The brief drawings, the suitable working pressure & temperature and material  of the main parts are indicated in attached drawing and tables.
3. Storage, maintenance, installation & operation
3.1 Storage maintenance
3.1.1 Gate Valve shall be stored indoor with dry and well-ventilated environment. The ends of the passage shall be plugged with covers.
3.1.2 Gate Valve stored for a long-term shall be checked periodically and cleaned to be free from stain. Especially clean the seat ring to protect sealing surface against damage, and coat corrosion-resistant oil the machined surface.
3.1.3 If the stored times exceed 12 months valve should be tested to ensure structural and functional integrity, and make a record.
3.1.4 Valve should be checked and repaired periodically after installation. The maintenance point includes:
(1) The sealing surface
(2) Stem and stem-nut
(3) Packing, O-rings
(4) The stain on the inside surface of body and bonnet
3.2 Installation
3.2.1 Assure valve mark (e.g. type, nominal size, nominal pressure, material etc.) is in accordance with the requirements of pipe system before installation.
3.2.2 Checking the passage and sealing surface carefully before installation. Clean it with bleached cloth if there is any dirt.
3.2.3 Before installation, be sure the packing are compacted tightly. But the movement of bleached cloth if there is any dirt.
3.2.4 Valve can be installed wherever it is convenient for examination and operation. The best location is horizontal and stem is vertical.
3.2.5 For normal closed valves, it’s not suitable to install at the place where working pressure vary large so as to avoid seats fatigue failure.
3.2.6 Install natural to avoid large stress resulted from the supports, attachments, piping etc.
3.2.7 Valve must be full opening during pressure testing of the pipe system after installation.
3.2.8 Supporting: if the pipe has enough strength to resist the valve weight and the operation torque, the support point isn’t need. Otherwise, the valve should have support point.
3.3 Operation and usage
3.3.1 Valve must be full-opening or full-closing during using to prevent sealing surface of seat from damage due to high-speed medium. Partial-open to adjust flow is not permitted.
3.3.2 Use handles instead of other tools when opening or closing valve.
3.3.3 Working pressure should not exceed maximum allowable working pressure under working temperature. The maximum allowable working pressure is PN20 to PN250.
3.3.4 Assure the momentary pressure is lower than 1.1 times of maximum allowable working pressure under working temperature.
3.3.5 Safety device shall be installed in the pipeline to prevent working pressure from exceeding maximum allowance pressure under working temperature.
3.3.6 Hit and beat of valve during transportation, installation, operation and maintenance is banned.
3.3.7 Decomposition of unstable fluids (e.g. decomposition of some fluids) will create expansion of volume and lead to rise of working pressure will lead to factors leading to decomposition of fluids.
3.3.8 If fluids is condensate enough to affect performance of valve, the user should make suitable measures to reduce the degree of condensation of fluids (e.g. ensure suitable temperature of fluids etc.) or replace other valve.
3.3.9 For self-ignition fluids, the user shall ensure environment and working temperature don’t exceed its self-ignition point. (Specially attention to external fire).
3.3.10 In any case, Replacing packing under pressure is not permitted.
3.3.11 Be sure the fluids is not dirty to affect performance of valve and no including hard solid particles, otherwise, should apply some appropriate measure to clean the dirty and hard solid particles or replace other type valve.
3.3.12 Apply suitable means by user to eliminate or resist corrosion and erosion of fluids and environment. The valve body material and working temperature would be as follows:
Item No. Body Material Working Temperature
1 ASTM  A216 WCB -29℃-425℃
2 ASTM  A217 WC6 -29℃-595℃
3 ASTM  A351 CF8C ≤540℃
3.3.14 Checking the scaling performance periodically during using as follows:
Check points Leakage
Body-bonnet connection Zero
Packing sealing, O-rings sealing Zero
Seat sealing Zero

3.3.15 Regularly check the wear of sealing surface, aging and failure of packing, O-rings. If that’s the case, repair or replace it in time.
3.3.16 After repairing, valve shall be reassemble and adjusted. Then test the sealing performance and make a record. The maintainer should have relative knowledge and experience of valve.
4. Guarantee
Guarantee period of valve is 12 months after using, but not exceed 18 months after delivery.

Manufacturer will repair or provide spare parts free of charge on the occurrence of damage due to material, manufacturing or the damager under correct operation condition during the guarantee period.

Source: China Gate Valves Manufacturer – Yaang Pipe Industry (www.ugsteelmill.com)

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