To ensure the measurement accuracy of the electromagnetic flowmeter, proper installation is very important.
The transmitter should be installed in a dry and ventilated place indoors. Avoid installation in places where the ambient temperature is too high, should not be subject to strong vibration, try to avoid equipment with strong magnetic fields, such as large motors, transformers, etc. Avoid installation in corrosive gases. The installation location is easy to overhaul. This is the environmental condition to ensure the normal operation of the transmitter.
In order to ensure that the measuring tube of the transmitter is filled with the measured medium, the stacker is preferably installed vertically, and the flow direction is from bottom to top. Especially for liquid-solid two-phase flow, it must be installed vertically. If the site is only allowed to be installed horizontally, it must be ensured that the two electrodes are at the same level.
The transmitter should be equipped with valves and bypass at both ends.
The millivolt AC potential measured by the electrode of the electromagnetic flow transmitter is based on the liquid potential in the transmitter. In order to stabilize the liquid potential and maintain the potential of the transmitter and fluid to ensure stable measurement, the transmitter shell and the metal tube should have good grounding at both ends, and the converter housing should also be grounded. The grounding resistance should not be greater than 10 and cannot be shared with the grounding wire of other electrical equipment. If the transmitter housing is not guaranteed to be in good contact with the metal pipe, connect them with metal wires. Re-reliable grounding.
In order to avoid interference signals, the signal between the transmitter and the converter must be transmitted with shielded wires. It is not allowed to place the signal cable and power cable in parallel in the same cable. The length of the signal cable should generally not exceed 30 m.
Converter installation site should avoid AC and DC strong magnetic field and vibration, ambient temperature is -20 to 50 ° C, does not contain corrosive gases, relative humidity is not more than 80%.
In order to avoid the influence of the flow rate on the relative measurement, the flow regulating valve should be placed downstream of the transmitter. For small-caliber transmitters, since the distance from the center of the electrode to the inlet end of the flowmeter is equivalent to several times the length of the diameter D, the upstream straight pipe may not be specified. However, for a flowmeter with a large diameter, generally there should be a straight pipe section of 5D or more in the upstream, and the downstream pipe section is generally not required.
Advantages of turbine flow meters
The pressure loss is small, and the impeller has anti-corrosion function;
1.Adopt advanced ultra-low power single-chip microcomputer technology, the whole machine has strong functions, low power consumption and superior performance.
2.Intelligent flow display with nonlinear accuracy compensation. Correction formula accuracy is better than ±0.02%
3.The meter factor can be set online by button and can be displayed on the LCD screen. The LCD screen is intuitive and clear, and the reliability is strong.
4.EEPROM is used to accumulate the flow and the meter coefficient is powered down. The protection time is more than 10 years.
5.Using high-performance MCU central processing unit to complete data acquisition and processing display output, cumulative flow instantaneous flow
6.The screen displays a convenient man-machine interface for data transfer in standard 485 format.
7.Fully hard alloy (tungsten carbide) shielded cantilever beam structure bearing, integrating rotary bearing and pressure bearing, greatly improving bearing life and working in medium with a small amount of sediment and dirt.
8.It adopts 1Cr18Ni9Ti all stainless steel structure (the turbine adopts 2Cr13) and has good anti-corrosion performance.
9.Easy to maintain, self-rectifying structure, small and light, simple structure, which can be combined in a short time.
10.Internal cleaning is simple.
11.Strong anti-magnetic interference and vibration capability, reliable performance and long life
12.The lower limit flow rate is low and the measuring range is wide.
13.The on-site display type LCD screen is clear and intuitive, with low power consumption. The 3V lithium battery can be operated continuously for more than 5 years.
Corrosion resistant, suitable for acid and alkali solutions
Third, the spiral vortex flowmeter measurement characteristics
The spiral vortex flowmeter is a flowmeter that began to appear in the 1970s. Its working principle is: the gas that enters the gas swirling vortex flowmeter is first forced by the spiral spinner to accelerate the rotation to form a vortex, the center of the vortex. For the vortex core. The accelerated vortex enters the enlarged section and then decelerates sharply. The pressure rises to produce a recirculation. Under the action of the recirculation, the vortex core makes a spiral precession around the axis of the flowmeter. The flow rate Q can be derived by measuring the vortex precession frequency f by sensing the sensitive component.
Fourth, gas turbine flowmeter and spiral vortex flowmeter measurement difference
The gas turbine flowmeter has a small pressure loss and can be suitable for gas metering in low pressure conveying applications. Gas-injected vortex flowmeters have a slightly higher pressure loss, and gas metering in low-pressure delivery situations sometimes has problems.
Gas turbine flowmeters require high media cleanliness and can be damaged if used improperly. The gas swirling vortex flowmeter gas swirling vortex flowmeter requires no gas turbine flowmeter and is not damaged.
Gas turbine flowmeters are highly accurate. It is the most accurate of all flow meters. The gas spiraling vortex flowmeter is not as accurate as the former.