Choice of protection level
The protection level of the electromagnetic flowmeter should be selected according to the actual situation. If the sensor is required to be installed below the ground and is often flooded, IP68 should be selected. If the sensor is installed above the ground, IP65 and IP67 should be selected. In any case, the display area of ??the electromagnetic flowmeter cannot be used with water or enter the water, which may cause damage to the electromagnetic flowmeter. As a chemical company, the workshop produces high humidity, but IP65 (IP65 is a water-proof type. The electromagnetic flowmeter sensor housing allows the faucet to spray water from the sensor in any direction of the sensor of the electromagnetic flowmeter. The pressure of the water spray is 30Kpa, the water output It is 12.5L/S and the distance is 3 meters.) The electromagnetic flowmeter of the protection grade fully meets the requirements of on-site measurement.
Choice of connection method
Electromagnetic flowmeters have threaded connections, flanged connections, clamps, etc. In the chemical industry, flange-connected electromagnetic flowmeters are generally used. The selection must be consistent with the process-flange engineering pressure and standards.
Conclusion, with the maturity of the domestic instrument industry, chemical companies such as lithium carbonate, boric acid and potash will also enter the market in line with the domestic market. As an important industrial flow measuring instrument, electromagnetic flowmeter should play its role in DCS control. The right selection is especially important to provide accurate measurement data, reduce labor costs and increase production efficiency.
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)
Second, gas turbine flowmeter measurement characteristics
1. Gas turbine flowmeter is one of the main types of flowmeters. Its working principle is: the gas entering the gas turbine flowmeter is accelerated by the fluid, and the accelerated gas acts on the blades of the turbine through the inlet passage. The impulse causes the turbine of the flow meter to rotate in the flow path, and within a certain flow range, the number of revolutions of the turbine is proportional to the volume of the gas flowing therethrough. By mechanical or electromagnetic induction, the number of revolutions f of the turbine can be obtained, so that the flow rate Q of the gas flowing through the flow meter can be obtained.
2. Gas turbine flowmeters are widely used in the measurement of gas flow or total gas volume, and are widely used in natural gas flow measurement at home and abroad. The theoretical research and practical experience of gas turbine flowmeters are very mature, and there are corresponding international standards. Countries also have corresponding national standards. China also adopts international standards. In Europe and the United States, gas turbine flow meters are the most important gas flow meters, and the Netherlands alone uses more than 2,600 gas turbine meters on natural gas pipelines.