Ordinary seawater butterfly valve, in order to adapt to the corrosion of chlorine ion in water, the valve body, disc and other accessories used duplex stainless steel, titanium alloy and aluminum bronze material, such as using the above materials seawater butterfly valve has its own defects, and can't fully meet the needs of the working condition of sea water.Such as titanium alloy butterfly valve, although various aspects performance is superior, but the titanium and titanium alloy smelting technology is difficult to access to the titanium alloy castings is more difficult, difficult to machining, and the price is very expensive.For duplex stainless steel butterfly valve, resistance to chlorine ion corrosion, but resistance to erosion ability is bad, port and vulnerable to erosion and damage on sealing surface, causing leakage butterfly valve sealing surface.

Seawater butterfly valve compared with ordinary water, has the following features:
    1. The butterfly plate after optimization design, can effectively increase the butterfly valve flow area, reduce the fluid resistance;
    2. According to different conditions, choose appropriate butterfly plate sealing ring, to ensure that the valve in a maintenance cycle won't produce leakage;
    3. The valve body, disc, ring and other components for the carbon steel materials, effectively reduce the manufacturing cost, all contact with the medium parts spraying ceramic wear-resisting corrosion resistant coating, such as to increase the valve of sea water corrosion and erosion resistance;
    4. The valve sleeve for duplex stainless steel materials, and with the shaft hole on the body USES the interference fit, effectively prevent the corrosion of the valve shaft hole position by the sea;
    5. Between the stem and the shaft sleeve in sha-lu, its purpose is: to prevent water infiltration between the stem and shaft sleeve, eliminate the seawater corrosion of stem and shaft sleeve.At the same time prevent mud sand in the water infiltration in the clearance between the sleeve and the valve stem, valve stem and shaft sleeve occlusion phenomenon, effectively improve the service life of the valve;
    6. Valve seat sealing surface welding duplex stainless steel, wear-resisting, resistance to erosion, effectively improve the valve seal reliability;

    7. The live load combination packing, PTFE namely V + V EPDM packing, ensure that the valve does not produce leakage in a maintenance cycle.

Keywords:butterfly valve ,knife gate valve,ball valve,globe valve,slurry gate valve