Pressure and temperature selection
The actual working pressure of the fluid in the pipeline should be less than the rated working pressure of the flowmeter. Pay attention to whether there is negative pressure in the pipeline, such as the evaporation process, and the negative pressure is up to -60KPa. Such working conditions should be communicated with the manufacturer's technicians when ordering. Strict requirements are imposed on the lining material. The actual temperature should meet the temperature requirements specified by the flowmeter.
Power supply selection
The choice of the electromagnetic flowmeter power supply should be selected according to the flowmeter itself and the environment of the site. If the site allows, the power supply is convenient, safe and easy to maintain. As a chemical company, more than 90% of the raw materials and process links are in the liquid phase. During operation, the internal humidity of the workshop is large, and no flammable gas is generated during the whole operation. It is safer to use DC24V for power supply. Outdoor dry environment, choose AC220V power supply, convenient lead wire, good maintenance and low cost.
Some explosion-proof occasions, such as flowmeters used in gas boilers, are ideal for battery-powered electromagnetic flowmeters.
The main technical parameters of ultrasonic external clamp flowmeter:
Measurement accuracy: better than 1%
Repeatability: better than 0.2%
Measurement period: 500ms (2 times per second, 128 sets of data collected per cycle)
Working power: 220VAC/8~36VDC
Maximum flow rate: 64m / s (flow rate resolution 0.001m / s)
Display: 2 × 10 Chinese characters backlit LCD can display instantaneous flow and positive, negative, net cumulative flow, flow rate, etc.
Operation: 4×4 touch keyboard (F4 main unit magnetic 4 button) operation
Signal input: 3 channels of 4-20mA analog input, accuracy 0.1%, can input pressure, liquid level, temperature and other signals
2-way three-wire PT100 platinum resistor
Signal output: 1 isolated RS485 output
1 way 4-20mA or 0-20mA output
1 channel isolated OCT (programmable between pulse width 6~1000ms, default 200ms)
1 relay output (pulse width 200ms)
Data storage: Optional built-in data storage (SD card) can store time, instantaneous flow, accumulated flow, signal status, etc., through special software, can import data into computer for statistical and management
Communication protocol: MODBUS protocol, M-BUS protocol, FUJI extension protocol, and compatible with communication protocols of similar products of other domestic manufacturers
Other functions: automatic memory before 512 days, the first 128 months, the first 10 years of positive / negative / net cumulative flow
Automatically remember the first 30 times of power-on and power-off time and flow rate, and can realize automatic or manual addition of traffic, which can be read by MODBUS protocol.
Programmable batch (quantitative) controller, fault self-diagnosis function
Software upgrade via code file transmitted via E-mail
Protection level: sensor IP68, F4 host IP68, remaining host IP65
Explosion-proof grade: EXdIIBT4 (JN-100F2 type)
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.