Electric control valve selection and installation of the product

Choose the point 1 a, electric control valve products. Choose the main control parameters of the electric control valve: nominal pressure, nominal diameter, design allowed temperature range, flow coefficient, etc. 2. Open for traffic and high proportional relationship of rigorous situation, should choose special regulator. High precision adjustment process to choose electric V regulator; Diameter > 200 optimizing electric butterfly valve series adjustment. 3. Examination is the sealing performance of the valve valve is one of the main indicators of quality. Valve sealing performance mainly includes two aspects, namely, internal leakage and leakage. Leakage refers to between the seat and closed on the degree of sealing medium to achieve. Leakage is refers to the stem packing parts of a leak, stem of the gasket leakage caused by casting defects of leaking, and the valve body. No leakage is allowed. 4. Regulating valve ideal flow characteristic have quick opening, parabola, linear, and other four percentage, need to choose according to actual work flow characteristic has the appropriate flow characteristic of regulating valve. Note: S = control valve fully open when the pressure loss/regulator series branch's total pressure loss. In order to avoid excessive water velocity of flow through valve and try to save the water pump power consumption, appropriate makes the working state of the valve S 0 or less. 7. 5. The selection of regulating valve nominal diameter should be determined according to the required valve flow capacity. Regulating valve nominal diameter should not be too big or too small. Increase the project cost is too big, and the valve is in low percentage range, accuracy is reduced, the control performance. Is too small, increase system resistance, can appear even open valve 100%, capacity requirements set by the system still cannot achieve. Pp ball valve type PVC ball valve pneumatic knife gate valve 1 second, construction installation points. Valve installation position, height, import and export direction must comply with the design requirements, the connection should be firmly connected. 2. Valves available various forms of end connected to the pipe. One of the main connection mode with screw thread, flange and welding connection. Flange connection, if the temperature exceeds 350 ℃, due to the creep relaxation bolts, flange and gasket, should choose high temperature bolt material. 3. A visual inspection must be conducted before installation of valve, the valve nameplate should be consistent with existing national standards GB12220 'universal signal valve' regulation. For the working pressure is greater than 1. 0 mpa and the valve with the function of cutting off on ZhuGanGuan, should carry on the strength and leak test, qualified rear must use. Other valves not tested alone, stay in the system pressure test. 4. Strength test, the test pressure for the nominal pressure of 1. 5 times, duration of not less than 5 min, shell and packing shall be no leakage of the valve. 5. Leak test, the test pressure for the nominal pressure of 1. 1 times; Test pressure constant, must be maintained in the duration of the test time shall comply with the provisions of the table 2, with no leakage for qualified for valve sealing surface. Table 2 electric control valve pressure test duration three executed standard electric actuator, electric valve standard: JB/T8219 - 1999 'industrial process measurement and control system using electric actuators standard' standard GB/T13927 - detection and execution 92 'general valve pressure test' JB/T5296 - 91 'general valve flow coefficient and flow resistance coefficient test method' (JB/T8528 - 1997 'the technical conditions of normal valve electric actuator GB12220 - 89 'general valve symbol' reference standard GB50243 - part of the project 2002 'ventilation and air conditioning engineering construction quality acceptance specification' GB50242 - 2002 the building water supply and drainage and heating engineering construction quality acceptance specification'