How to Choose Electric Ball Valves? - Part One

When we purchase the electric ball valve, only the specification, category and working pressure can meet the purchasing requirements. Under the unified design concept of the electric ball valve, different innovations will be carried out, forming their own enterprise standards and product personality.

I. General requirements
1. The specification and category of electric ball valves shall meet the requirements of pipeline design documents.
2. The model of electric ball valves shall indicate the requirements of national standard number. If it is an enterprise standard, the relevant description of the model shall be indicated.
3. The working pressure of electric ball valves is required to be greater than or equal to the working pressure of pipelines. On the premise of not affecting the price, the working pressure that the electric ball valve can bear should be greater than the actual working pressure of the pipeline. Any side of the electric ball valve should be able to bear 1.1 times of the working pressure of the electric ball valve without leakage. When the electric ball valve is opened, the valve body should be able to withstand the requirement of twice the working pressure of the electric ball valve.

II. Gearboxes
1. The box material and internal and external anti-corrosion requirements are consistent with the valve body principle.
2. Sealing measures shall be taken for the box, which can withstand the immersion of 3M water column after assembly.
3. The adjusting nut of the opening and closing limiting device on the box should be inside or outside the box, but it can only be operated with special tools.
4. The design of transmission structure is reasonable. When the valve is opened and closed, the valve shaft can only be driven to rotate, so that it does not move up and down. The transmission parts bite properly, and there is no separation and slipping when the it is opened and closed with load.
5. There is no foreign matter in the box, and the gear engagement part should be protected by grease.

III. Standard quality of electric ball valves
1. The valve body material should be mainly nodular cast iron, and the brand and actual physical and chemical test data of cast iron should be indicated.
2. The valve rod material shall be stainless steel (2CR13), and large diameter electric ball valve shall also adopt stainless steel embedded stem.
3. The nut is made of cast aluminum brass or cast aluminum bronze, and its hardness and strength are higher than those of valve stems.
4. The hardness and strength of the valve stem bushing material shall not be greater than that of the valve stem, and there shall be no electrochemical corrosion with the valve stem and valve body under the condition of water immersion.
5. Valve shaft packing
① As the electric ball valve in the pipe network is usually opened and closed infrequently, it is required that the packing shall not be active for several years. The packing shall not be aged so as to maintain the sealing effect for a long time.
② The sealing effect of the valve shaft packing shall also be good under the condition of frequent opening and closing.
③ In view of the above requirements, the shaft packing shall not be replaced for more than ten years.
④ If the packing needs to be replaced, the electric ball shall be replaced and the replacement measures under the condition of water pressure should be considered for valve design.