The quality of ball valve material is an important determinant of the overall performance of the valve, so we should also have a certain understanding of the material of all its accessories when selecting the valve. Then, let's give you a detailed introduction to the purchasing skills of each accessory material:
1. Valve material: as gray cast iron pipe is recommended gradually, ductile iron shall be the main material of valve body, the brand actual physical chemical test data of casting shall be indicated.
2. Stem material: stainless steel stem (2Cr13), large diameter valve should also be stainless steel embedded stem.
3. Nut material: cast aluminum brass cast aluminum bronze, the hardness strength are greater than the valve stem.
4. Material of valve stem bushing: its hardness strength shall be greater than that of valve stem, electrochemical corrosion with valve rod valve body shall be formed under water immersion condition.
5. Material of sealing surface:
① There are different types of ball valves, different sealing methods material requirements;
② For ordinary wedge gate valve, the material, fixing method grinding method of copper ring shall be specified;
③ Physical, chemical hygienic test data of soft seal gate valve valve plate rubber lining material;
4. The butterfly valve should mark the material on the sealing surface of the valve body the material of the sealing cover on the butterfly plate; their physical chemical test data, especially the hygienic requirements, anti-aging wear-resisting properties of the rubber, usually adopt butadiene rubber three yuan ethylene propylene rubber, so on, strictly prohibit the addition of reclaimed rubber.
6. Shaft packing:
① Since the valves in the pipe network are usually opened closed infrequently, it is required that the packing should be inactive for several years, the packing should be aged to maintain the sealing effect for a long time;
② The packing of ball valve shaft should also have good sealing effect when bearing frequent opening closing;
③ In view of the above requirements, the shaft packing shall be replaced for life more than ten years; ④ if the packing needs to be replaced, the valve design shall consider the replacement measures under the condition of water pressure.
To sum up, is the valve material selection skills related to the introduction, so that you can use the above method in the selection process in the future, both time-saving labor-saving.