The mediums that need to be measured in the site are different. Now, a brief introduction is made on the selection of flow meters for different media.
The selection of large water flow meter: suitable for electromagnetic flowmeter, ultrasonic flowmeter. Other applications such as vortex flowmeters, orifice flowmeters, etc. have faded out of this application, and these two types of flow meters are the most important in the industry. In particular, it should be mentioned that the application of Kaifeng Shengda's plug-in flowmeter and electromagnetic flowmeter are better.
Sewage, pulp and other turbid liquid meter selection: electromagnetic flowmeter can be used. However, when choosing an electromagnetic flowmeter, consider that the liquid does not contain more air or bubbles.
The meter with more bubbles of liquid selection: Doppler ultrasonic flowmeter can be selected, using this type of flowmeter to measure the fluid with bubbles, the effect is very good.
Flow meter selection with low conductivity such as pure water and demineralized water: Turbine flow meter is very suitable for measuring such fluids.
Flow meter selection for strong corrosive media such as acid and lye: 1. Electromagnetic flowmeter with acid and alkali lining. 2. clamp type ultrasonic flowmeter.
Selection of flowmeters for mediums with large concentration and large solid particle content such as mortar and electric powder slurry: electromagnetic flowmeter.
Flow meter selection for oil media such as oil and diesel: turbine flow meter and ultrasonic flow meter.
Gas flow meter selection: vortex flowmeter.
First, the gas turbine flowmeter installation requirements
1. When the gas flowmeter is installed, it is strictly forbidden to directly conduct electric welding at the inlet and outlet flanges to avoid burning the internal parts of the flowmeter;
2. For the newly installed or overhauled pipeline, it must be purged to remove the debris in the pipeline before installing the flowmeter;
3. The gas turbine flowmeter should be installed in a place that is easy to maintain, has no strong electromagnetic field interference, no mechanical vibration and thermal radiation;
4. Gas turbine flowmeters should not be used in places where flow is frequently interrupted and there is strong pulsating flow or pressure pulsation;
5, the gas turbine flowmeter should ensure that the pipeline is coaxial, and prevent the gasket from protruding into the pipeline, otherwise it will disturb the flow profile;
6. The flow direction of the gas turbine flowmeter should be consistent with the direction marked on the casing. The upper and lower pipelines of the flowmeter should be guaranteed with 2DN and 1DN straight pipe sections;
7. When using external power supply, the flowmeter must have reliable grounding, but it should not share the grounding wire with the high-power system; when the pipeline is installed or repaired, the grounding wire of the welding system should not be overlapped with the flowmeter.
8. Since the flowmeter needs to be repaired and calibrated, in order to ensure normal gas supply, bypass piping should be set. The bypass pipe valve must be closed during normal use;
9. When constructing pipelines, it is advisable to install telescopic tubes or bellows to avoid serious stretching and causing breakage of the flowmeter;
10. When the gas turbine flowmeter is installed outdoors, the upper part should be covered to prevent the rainwater from immersing and the sun exposure affecting the service life of the flowmeter;
11. When installing the gas turbine flowmeter, it is advisable to add a filter to the flowmeter (filtering accuracy is recommended ≤20μm).
Second, gas turbine flowmeter requirements
1. When the gas turbine flowmeter is put into operation, the upstream valve of the flowmeter should be slowly opened (not less than 15 seconds), and then the downstream valve of the flowmeter should be slowly opened to prevent the instantaneous airflow from rushing to the turbine;
2. When the flowmeter needs to have a long-distance signal, it should be connected to the external power supply (+12~+24VDC) strictly according to the electrical performance index of the gas turbine flowmeter. It is strictly forbidden to directly connect 220VAC (or 380VAC) power supply at the signal output.
Selection of measurement types for special industrial and commercial users
2. Case 2: A heavy machine tool factory
The main gas plant of the heavy-duty machine tool factory is 13 production kiln, and there is also a machine repair workshop and 63 mobile burners. The total gas load of all gas facilities is 1837m3/h. See Table 1 for details. The customer promised that all gas facilities could not be fully activated at the same time, the maximum gas consumption required was 1200m3/h, and the minimum pressure required before the furnace was 0.055MPa. The pressure regulator used in the on-site pressure regulating metering box is opened and ready, and the flow meter is in the form of a G1600 turbine table plus bypass.
When debugging the kiln, it was found that the flowmeter in the pressure regulating metering box had a stop-and-go phenomenon. If only some of the kiln was opened or only some of the kiln was used, there would be a phenomenon that the flowmeter did not measure or the measurement error was large.