Electromagnetic flowmeter features
Using intelligent judgment, the measurement correction setting is not used, and the air traffic control alarm and electrode detection application are more convenient;
Advanced "rough error handling" technology, which can remove fluids such as slurry to measure sharp disturbances, reduce output runout, maintain high precision measurement and make output more stable;
With a fluid density setting, it can display mass flow;
Constant current excitation current range, 125mA, 250mA optional, can be used with different manufacturers, different types of electromagnetic flow sensors;
Control function with remote reset of the totalizer, with contact signal input for starting and stopping accumulation, suitable for total inspection and batch processing applications;
With self-test and self-diagnosis function;
Advanced non-volatile memory for higher circuit reliability and effective protection of setup and measurement parameters;
The meter can be equipped with an unpowered clock and memory for recording the power down time, power-on time and power-down time;
The meter has an optional hour recording function that can store flow and electrode resistance measurements for more than 30 days.
The new keyboard processing method avoids the keyboard operation affecting the measurement, and can enter and return the operation menu to make the parameter setting more convenient;
The total display uses 10-bit decimal 9999999999 full-value carry, which solves the practice of double-word full value 4294967285 (hexadecimal FFFF) carry-in habit;
With wireless transmission, the mesh network is organized by the wireless HART protocol.
Vortex flowmeter selection
(1) Selection of vortex flow transmitter
In the measurement of saturated steam, VA type piezoelectric vortex flow transmitter is adopted. Because of the wide range of vortex flowmeter, in practical applications, it is generally considered that the flow of measuring saturated steam should not be lower than that of vortex flowmeter. The lower limit, that is to say, the fluid flow rate must not be less than 5 m/s. According to the size of the steam, the vortex flow transmitters with different calibers are selected, and the caliber of the transmitter cannot be selected by the existing process pipe diameter.
(2) Selection of pressure compensation pressure transmitter
Since the saturated steam line is long and the pressure fluctuates greatly, pressure compensation must be adopted. Considering the corresponding relationship of pressure, temperature and density, only pressure compensation can be used in the measurement, because the saturated steam pressure of Mingtong Company is 0.3-0.7MPa. Range, the range of pressure transmitter can be selected 1MPa.
(3) Display instrument selection
Display instrument intelligent flow display instrument with voltage regulation compensation, instantaneous flow display and cumulative flow accumulation function.
Vortex flowmeter analysis and solution
Summarizing the main causes of these problems, mainly related to the following aspects:
1. Problems with selection. Some vortex sensors are selected on the caliber selection or after the design selection, due to the change of process conditions, so that the selection is larger, the actual selection should be as small as possible to improve the measurement accuracy. The main reason for this is the same. Questions 1, 3, and 6 are related. For example, a vortex pipeline is designed for use by several equipment. Because some of the equipment is not used, the actual actual flow is reduced. The actual design results in too large an original design, which is equivalent to an increase in measurable flow. The lower limit, when the process pipe has a small flow rate, the indication cannot be guaranteed. When the flow rate is large, it can be used, because it is sometimes too difficult to re-engineer. Changes in process conditions are only temporary. The re-tuning of the parameters can be combined to improve the indication accuracy.
2. Installation problems. The main reason is that the length of the straight pipe in front of the sensor is not enough, which affects the measurement accuracy. The reason for this is mainly related to the problem 1. For example, the straight pipe section in front of the sensor is obviously insufficient. Since the FIC203 is not used for measurement, it is only used for control, so the current accuracy can be used equivalent to the downgrade.