double check valves
Double Check Valve, in control of the body and bonnet structure units sealed in a fluid channels for combined with seating fluid export activities of Check Valve closed structure, cover the transition in setting a structure and check the sealing structure under the direction of movement coaxial overhanging stem, which can make the Settings for axial positioning control structures under lock and the lower end of the stem and said check closed structure to make contact with the type, the upper and lower stem for control of the stem. The double check valve control can be realized as conventional stopped flowing pressure loss or close, in order to protect the function of measuring structure from the back of the damage caused, and may, according to needs, by human control on the mandatory open or closed, in order to meet the needs of the use of cases.
