Save Money: Things You Must Know Before Purchasing Valves!

8th October, 2024


Valve is an indispensable control element in the fluid transportation system, which is responsible for controlling the flow of fluids, including but not limited to cut-off, regulation, inflow, prevent backflow, stabilize the pressure, shunt or pressure relief and other functions. Valves are available in a wide variety of types, suitable for controlling a variety of fluids, such as air, water, steam, corrosive media, slurry, oil, liquid metals and radioactive media. Valves are also available in a variety of materials, including cast iron, cast steel, stainless steel, chromium-molybdenum steel, chromium-molybdenum-vanadium steel, duplex steel, plastics, etc., and can even be customized off-standard.


When purchasing and selecting valves, the following technical points should not be ignored:


Valve Specifications & Types: 

Must match the pipeline design documents.


  1. Valve type should follow the required national standard number, and if it is a non-standard product, it is necessary to provide a detailed description of the type.

  2. The working pressure of the valve should not be lower than the pipeline working pressure, and in the case of reasonable price, the valve should withstand pressure higher than the actual working pressure.

  3. Valve in the closed state, should be able to withstand 1.1 times the working pressure without leakage; in the open state, the valve body should be able to withstand twice the working pressure.


Valve Material Selection:


  1. As gray cast iron is gradually eliminated, ductile cast iron becomes the mainstream material.

  2. Stem material should be preferred to stainless steel (2CR13), large-diameter valve stem should also be wrapped in stainless steel.

  3. Nut material is recommended to use cast aluminum brass or cast aluminum bronze, hardness and strength should be higher than the valve stem.

  4. Stem bushing material hardness and strength should be no higher than the valve stem, and underwater does not produce galvanic corrosion with the valve stem or valve body.


Requirements for Variable Speed Transmission Box:


  1. The box material and anti-corrosion requirements should be consistent with the valve body.

  2. The box should have sealing performance and be able to withstand immersion in 3 meters of water column.

  3. The transmission structure should be reasonably designed to ensure that the valve shaft only rotates and does not move up and down when opening and closing.

  4. The inside of the box should be free of debris, gear parts should be protected by grease.


Valve Operating Mechanism:


  1. The opening and closing direction of the valve should be unified for clockwise closing.

  2. Considering the convenience of manual operation, the number of opening and closing turns should not be too much.

  3. Under the working pressure of the pipeline, the maximum opening and closing torque should be controlled within 240m-m.

  4. The operating end should be standardized for easy ground operation.



Valve Performance Testing:


  1. When mass production, the performance test should be entrusted to authoritative organizations.

  2. Internal pressure test and sealing performance test should be carried out before leaving the factory.


Anti-corrosion Treatment of the Valve:


  1. The inside and outside of the valve body should be shot blasted and sand blasted to remove rust, and sprayed with non-toxic epoxy resin.

  2. The internal anti-corrosion should be comprehensive to reduce the resistance to over-watering.


Packing and Transportation of the Valve:


  1. Both ends of the valve should be fixed with lightweight plugging plates.

  2.  Small and medium diameter valves are recommended to be bundled with straw ropes and transported in containers.

  3. Large diameter valves should be fixed with wooden bar frame to prevent damage during transportation.


Factory Instructions for Valves:


The supplier should provide the corresponding factory instructions, the instructions contain should contain all the key data of the valve, such as specifications, models, working pressure, manufacturing standards, materials, operating direction, number of revolutions, opening and closing torque.


EATHU is known for innovative technology, quality materials and strict quality control, providing customized solutions to meet specific customer needs. We focus on environmental protection, provide cost-effective products and ensure customer satisfaction with quick response and a global supply chain.



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