The selection of electric control valve caliber adopts the method of calculating the flow capacity C value
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2014-10-07
Selection of deaerating pressure regulating valve and Mode of action of pressure regulating valve: considering the safe operation of deaerator, the valve position of deaerating pressure regulating valve should be fully open in case of accident, so as to prevent steam from entering the deaerator. Therefore, the Mode of action of the regulating valve must be electrically open. The flow characteristics of the deaerator should choose equal percentage flow characteristics. Selection of structural form of pressure regulating valve: Due to the low working pressure of the pressure regulating valve, the general pressure before the valve is 200-300KPa, and the pressure of the regulating valve inside the deaerator is ZOKPa, so a single seat valve can be selected. In addition to using the method of calculating the flow capacity C value to determine the diameter of the electric regulating valve, empirical methods can also be used to determine the diameter of the regulating valve.
When using SW-1 type sensors, the range of the supporting differential pressure transmitter is selected from 0 to ZKpa, and the scale of the secondary meter can be O% -100%. 5.7 Measurement of coal supply quantity is very difficult in coal-fired boiler rooms, and there is currently no accurate measurement method. Most coal quantity meters produced in China are measured using the volumetric method, which uses the number of revolutions (grate length) x grate width x coal seam thickness x coal specific gravity to obtain the coal supply. Due to the fact that the width of the grate, the thickness of the coal seam, and the specific gravity of the coal are known and can be seen as constants, the coal supply quantity becomes a function of the grate speed, and the measurement of the coal supply quantity also becomes a measurement of the grate speed. Therefore, in the automatic combustion control system, the speed of the grate speed control motor is used to represent the coal supply quantity. The regulation system does not require high accuracy in coal supply, and requires the coal supply signal to change accordingly with the load. In the thermal inspection and control system of coal-fired boiler rooms, there are many types of instruments and equipment involved, including temperature, pressure, flow rate, and various control valves. With technological progress, various new detection instruments and equipment continue to emerge, especially the rapid development of computer technology, which has brought broad prospects for boiler thermal inspection and control. However, in the use, transformation, and maintenance process of some in-service boilers, Some conventional instruments and control devices still occupy a certain proportion in civil and industrial boilers. The above author only provides a superficial understanding of the selection of some conventional instruments and equipment in boiler inspection and control in work practice. Please correct any shortcomings.
