Selection of electrodes and lining
Standard electrodes are used for media that do not produce non-staining electrodes such as crystals, agglomerates, and scales. Otherwise, a doctor blade electrode is used. In addition to the pure alkaline solution, the dosing solution (crystallization of boron and magnesium double salt), the washing liquid and other electromagnetic flowmeters that use the scraper electrode, the other uses the electromagnetic flowmeter of the standard electrode. Since the process pipes in the workshop are basically made of plastic insulation material, if the electromagnetic flowmeter with two electrodes is selected, the grounding ring must be configured to ensure the measurement accuracy. However, the common grounding ring is easy to corrode, and the corrosion-resistant titanium or 钽 grounding ring is high in cost, so the three-electrode electromagnetic flowmeter is selected to ensure measurement accuracy, reduce cost, and convenient installation and maintenance.
Flowmeter type selection
The types of electromagnetic flowmeters are divided into: integral type and split type. In Qinghai, the coldest temperature in winter is up to -30 °C. Many metered electromagnetic flowmeters are outdoors, and the environmental humidity of magnesium-lithium separation, pressure filtration and washing processes in lithium and boron systems is large. Exquisite, evaporation, conversion and other processes up to 90 °C. Therefore, the humidity of the high temperature, low temperature, high temperature fluid, vibration source and other working conditions select a split flow meter to effectively prevent the impact on the measuring components, to ensure measurement accuracy and the life of the electromagnetic flowmeter. However, it should be noted that the signal cable between the electromagnetic flowmeter sensor and the transmitter should not be too long, and the manufacturer-specific cable should be used, otherwise the measurement accuracy will be affected. The rest of the working conditions are more ideal.
Steam vortex flowmeter measurement requirements
Keywords: steam vortex flowmeter, saturated steam vortex flowmeter, superheated steam vortex flowmeter
What should I pay attention to when measuring vortex flowmeter? What is the best way to measure steam installation by vortex flowmeter? Can vortex flowmeters be used for steam metering? The vortex flowmeters are evaluated for their measurement performance under single-phase flow conditions. There is currently no single-phase flowmeter for measuring the system variation of two-phase flow. However, the two-phase flow exists objectively, and its influence on flow measurement is unavoidable. Despite the difficulties, people are still trying to study the mechanism of its influence on flow measurement, and take corresponding countermeasures to improve the accuracy of flow measurement.
First, steam flow measurement difficulties
During long-distance transportation, dry steam will partially condense due to heat loss, resulting in reduced steam dryness and become wet steam. The gas-liquid two-phase flow structure in the horizontal pipe is related to the gas-liquid two-phase volume ratio and the flow velocity. In the steam pipe, since the volume ratio of the condensed water in the wet steam is small, the drain pipe drawn from the bottom of the horizontal pipe is made. , can receive a good hydrophobic effect. When the flow rate is particularly high, it will also behave as a circular flow, that is, there is a liquid film on the pipe wall, and the central part of the pipe is a gas core with droplets. Due to the influence of gravity during horizontal flow, the lower liquid film is higher than the upper pipe. The thickness of the wall, in the vertical ascending pipeline, the basic structure of the gas-liquid two-phase flow has a fine bubble flow structure, a bullet-like flow structure, a block flow structure, a ring-shaped flow structure with fibers, and an annular flow structure.
Second, the gas turbine flowmeter projection operation steps
1. Open the bypass shut-off valve;
2. Open the flow upstream shutoff valve;
3. Slowly open the downstream shutoff valve of the flowmeter;
4. Slowly close the bypass shutoff valve.
Third, the gas turbine flowmeter stop table operation steps
1. Open the bypass shut-off valve;
2. Turn off the downstream shutoff valve of the flowmeter;
3. Close the flow upstream shutoff valve;
Fourth, gas turbine flowmeter use precautions
1. The newly installed or repaired pipeline must be purged. When purging the metering line, the flow meter must be removed and the corresponding short section replaced the flow meter for purging.
2. When the gas turbine flowmeter pipeline is put into production, it should be slowly boosted and gradually increase the flow rate. When the production is stopped, it should be slowly depressurized.
3. Check the sound of the gas turbine flowmeter or the vibration of the casing during operation to determine whether the turbine blades and bearings are working properly. At low flow rates, attention should be paid to the change in sound, and the vibration of the casing is observed at high flow rates.