Application of Siemens Electric Valve in Steam Decompression

After the boiler outputs steam, the pressure in the pipeline is generally higher. After reaching the client, it needs to be decompressed for the load to use. At present, most users adopt the installation of mechanical pressure reducing valve on the front of the sub-cylinder. Although this method is simple, there are some shortcomings that can not be overcome and the price of the imported pressure reducing valve is not high. Mechanical pressure relief valve generally has the following disadvantages: 1, the steam load flow or no flow case back-end steam pressure will gradually rise, can not maintain the set pressure. 2, the condensate in the pipeline more circumstances, there will be unreliable movements. 3, the pressure setting adjustment is not intuitive, inconvenient, in the case of higher installation position, according to changes in load demand is not easy to adjust, can not be adjusted remotely. 4, can not turn off steam automatically. Some loads in the power outage or safety potential need immediate stop steam, mechanical pressure reducing valve can not do it. 5, mechanical pressure reducing valve pressure regulating range is limited, some of the pressure requirements are particularly low load can not meet the requirements. 6, higher failure rate. Easy to appear capillary or balance hole blockage, membrane deformation, rupture, leakage and so on. In view of the above problems, I specially designed a Siemens steam valve for steam decompression program, the use of this program for steam pressure regulation implementation of two years of operation and stability, in order to have a fault, a very good solution to the above problems. The detailed plan is as follows: 1. Piping connection diagram: ① P steam source ② SF1 2 3 manual shut-off valve ③ GLQ filter ④ DF Siemens electric steam valve VVF45.504 ⑤ P1 2 3 Pressure gauge ⑥ FQG steam sub-cylinder ⑦ L1 2 3 steam load 2, the circuit diagram components list: ① K1 circuit breaker 2P 5A ② K2 circuit breaker 1P 3A ③ KZQ digital loop regulator RKC CD901 ④ CGQ pressure sensor Siemens OBE2000-P16 ⑤ T transformer 220VAC / 24VAC 150AV ⑥ ZXQ electric valve implementation Siemens SKD653, RKC controller parameter settings ①, PID can only be manually set according to the actual load, but also have automatic calculation (ATU) function to complete. ②, SL1 input type selection voltage 0 ~ 5V voltage input (1110). ③, SL4 The first alarm mode selection uses the upper deviation alarm (0001). ④, SL6 control output type selection 4 ~ 20mA continuous output (0111). ⑤, SL7 alarm relay status selection is set to 01, that is, when the alarm 1 alarm NC has become NO. ⑥, SLH set the maximum measurement range of 8.00, which corresponds to 0.8Mpa. ⑦, SLL set the lower limit of the measurement range of 0.00, which corresponds to 0Mpa. ⑧, PGDP set to 2 decimal places. ⑨, other parameters can use the default value. 4, Matters needing attention ①, pay attention to the choice of electric valve actuator to reference steam pressure and set pressure, actuator size and pressure to match the size, otherwise, may be lax or open. ②, the pressure sensor should be installed in the sub-cylinder, there must be a bend and a section of the export pipe, to avoid the impact of the sensor and the temperature is too high, reducing service life. ③, 4 ~ 20mA control signal into the AL1 and then to the actuator is in the pressure relative to the set value is too high, when the alarm value exceeds the AL1 action disconnect the control signal to fully close the motor valve. ④ The existing settings SL1, SLH, SLL determine the measurement range between 0 ~ 8Mpa, the sensor can measure to 1.6Mpa, if you need a larger measuring range, the need to convert the input signal through an external line, and the SLH, SLL set again. ⑤, the measurement shows a slight error can be calibrated by PB value. The program pressure shows that the settings directly on the controller, the adjustment easy to use, small pressure fluctuations, reliable operation, to save steam energy consumption also has some help. The price is slightly lower than the imported mechanical pressure reducing valve, which is a worth promoting method. The disadvantage is that you must need power, no power can not be used.