Several problems of solutions
Recalculating the differential pressure scale
Temperature and pressure compensation can only reduce the measurement error, not only can not solve the problem fundamentally, but also the measurement signal exceeds 20mA, resulting in steam leakage measurement. The transmitter measurement signal exceeds 20 mA, indicating that the actual measured differential pressure signal ΔP exceeds the design differential pressure value.
Increase temperature and pressure compensation
When the temperature and pressure of the steam change, the density of the steam changes, and the steam flow measurement produces an error. Measurement error can be reduced by temperature and pressure compensation. Since the temperature of the saturated steam is a single-valued function of the pressure, the temperature and pressure compensation of the saturated steam can be pressure compensated or temperature compensated. Because the pressure signal detection is sensitive and the compensation accuracy is high, it is compensated by pressure and realized by DCS.
Conclusion
Steam is a special medium. As the pressure and temperature change, the density of steam changes. Therefore, it is necessary to compensate for temperature and pressure. When the pressure and temperature fluctuation of the steam are not large, that is, when the operating condition parameters deviate from the design parameters and the influence on the measurement is small, the temperature and pressure compensation measures can achieve the purpose of accurate measurement. However, when the operating parameters deviate too much from the design parameters or the operating parameters fluctuate frequently and are too large, even with the temperature and pressure compensation, it is difficult to meet the measurement accuracy requirements. At this point, only differential pressure or flow can be recalculated for a particular throttling element.
Third, gas turbine flowmeter daily inspection
1. Look at the display: Observe the total amount, instantaneous, temperature, pressure, and battery power. If the abnormality is reported in time.
2. Listen to the running sound of the flowmeter. (Method) The flowmeter should have no noise when it is running normally. If there is a large abnormal noise, it can be judged as damage to the movement of the movement (for example). It needs to be reported and processed in time.
3, data comparison, the output of the first 3 to 5 days before the statistics, if there is no major change, the flowmeter runs normally, such as the successive decrement phenomenon, the gas turbine flowmeter impeller (shaft, shaft core), filtration There is a problem with the device. Need to be reported in time for processing
4, gas turbine flowmeter filling lubricant
(1) Instrument refueling is an important part of the daily maintenance work of the instrument. Lubricating oil is mainly for instrument bearing; lubricating oil can protect the instrument bearing, reduce friction, reduce wear and prolong the operation cycle of the instrument;
(2) Regularly adding lubricating oil can effectively reduce the maintenance rate of the instrument and reduce the maintenance cost;
(3) Ensure the measurement accuracy of the flowmeter. "Measuring is counting money." why would you said this? The management of production and operation accounting, energy saving, cost accounting, etc. is an important production link of enterprise management. If the measurement is not in place, it will affect the economic efficiency and reputation of the enterprise. Therefore, the daily maintenance of the instrument is very important.
Installation of plug-in electromagnetic flowmeter
The plug-in electromagnetic flowmeter sensor installation upstream straight pipe section is not less than 5D (D means pipe diameter), the downstream straight pipe section is not less than 2D:
1. Vertical installation. When the sensor is inserted into the pipeline, it should be less than 5° from the vertical diameter of the pipeline section. It is suitable for measuring the cleaning medium with small vibration of the pipeline.
2, inclined installation, the axis of the sensor and the axis of the pipe to be tested is 45 °, suitable for large pipe diameter and measuring the flow of liquid containing other impurities in the medium, the installation method is small, not suitable for entanglement.
There are two ways to insert the insertion point of the electromagnetic flowmeter sensor: one is inserted into the central axis of the pipe to be tested (ie 1/2 times the diameter of the pipe); the other is inserted into the inner wall of the pipe at 1/4 of the pipe.
Sensor installation:
1. Clean the welding slag and burrs of the base of the pipe to be tested.
2. Turn off the upstream flow control valve or use low pressure water supply.
3. Install the DN50 ball valve on the mounting base. Pay attention to the long cavity of the ball valve. Check whether the ball valve can be fully open and fully closed. Install the screw seat, compression nut and rubber sealing ring onto the ball valve and loosen the positioning nut. Insert the sensor into the rod through the ball valve and insert it into the pipe to be tested. At the same time, it should be noted that the direction of the sensor direction indicator rod should be consistent with the flow direction of the fluid. Ordering Information Please specify the name of the tested medium, working pressure, medium temperature, flow rate (flow rate) range, pipe diameter and the pipe network to be tested.