Gas Turbine Flowmeter Overview
The gas turbine flowmeter adopts advanced microprocessing technology and has the advantages of strong function, high calculation accuracy and reliable performance. Its main technical indicators have reached the advanced level of similar foreign products. It is an ideal instrument for gas measurement in petroleum, chemical industry, electric power, metallurgy, industrial and civil boilers, urban natural gas, gas pressure regulating station measurement and gas trade measurement. Its working principle is: when the gas enters the flow meter, it is first accelerated by a special rectifier. Under the action of the fluid, the turbine overcomes the resistance torque and friction torque and starts to rotate. When the torque reaches balance, the rotation speed is stable, and the rotation speed of the turbine is proportional to the gas flow rate. Proportional to the sensor, the magnet on the rotating transmitter plate periodically changes the sensor's reluctance, so that the sensor outputs a pulse signal that is proportional to the flow rate. The product has the following features:
1. It adopts special precision bearings imported from Germany, with high accuracy, good stability and wide range (20:1). Small diameters can be exempted from refueling for five years under normal use conditions, while large diameters only need occasional refueling. convenient.
2. The carefully designed flow channel structure avoids the flow of air between the bearings and improves the medium adaptability of the turbine flowmeter.
3. Unique reverse thrust structure and sealing structure design ensure long-term reliable operation of the bearing.
4. The use of magnetoresistive elements instead of magnetic sensitive coils not only avoids the existence of magnetic attraction, but also improves detection sensitivity, further reduces the initial flow rate, and improves the stability and reliability of the product.
5. Independent movement design, good interchangeability and easy maintenance.
6. It integrates temperature, pressure, flow sensors and intelligent flow totalizer into one, which can automatically track and correct the temperature, pressure and compression factor of the measured gas, and directly measure the standard volume flow and total amount of the gas.
7. The main performance indicators have reached the international advanced level and comply with ISO9951 standards.
8. Adopting micro-power consumption high technology, it can work with both internal and external power sources, and the internal battery can be used continuously for more than five years.
9. Powerful functions, four compensation methods, three pulse signal outputs, three historical data recording methods, and two standard current signal output methods are optional.
10. The network communication system is formed through the RS485 interface, which can facilitate automatic management. The RS485 communication protocol complies with the MODBUS specification.
11. The meter head can be rotated 180° at will and is easy to install.
Main technical parameters of gas turbine flowmeter
2.1Measurement medium
Natural gas, city gas and other gases, alkanes and industrial inert gases.
2.2 Conditions of use
◆Ambient temperature: -30℃~+60℃; ◆Media temperature: -20℃~+80℃;
◆Atmospheric pressure: 70kPa~106kPa; ◆Relative humidity: 5%~95%.
2.3 Electrical performance indicators
2.3.1 Working power supply and power consumption
a. External power supply: +24VDC±15%, suitable for 4mA~20mA output, pulse output, RS485, etc.;
b. Internal power supply: 1 set of 3.6V lithium battery, which can be used continuously for more than five years.
2.4.2 Pulse output mode (LWQ type can choose one of the following three by setting)
a. Working condition pulse signal, photoelectric isolation amplification output, high level amplitude ≥ 20V, low level amplitude ≤ 1V.
b. The frequency signal proportional to the standard accumulation flow rate is amplified and output through photoelectric isolation. The high-level amplitude is ≥20V and the low-level amplitude is ≤1V.
c. Calibrated pulse signal (matched with IC card valve controller), high-level amplitude ≥ 2.8V, low-level amplitude ≤ 0.2V, unit pulse represents the volume that can be set in the range: 0.01m~10.00m.
2.4.3 RS485 communication (using photoelectric isolation RS485 communication module), which can be directly connected to the upper computer or secondary instrument network, and the current data and historical records can be displayed remotely.
2.4.4 4mA~20mA standard current signal (using photoelectric isolation standard current module); two-wire or three-wire system.
2.4.5 Control signal output
a. Upper and lower limit alarm signals (UP, LP): Photoelectric isolation opens the collector (OC) output, the OC gate is cut off in the normal state, and the OC gate is turned on in the alarm state. The maximum load current is 50mA, and the operating voltage is +12VC~+24VDC.
b. Valve closing alarm (BC) and battery undervoltage alarm (BL) output (for IC card controller); logic gate circuit output, normal output low level, amplitude ≤ 0.2V; alarm output high level, amplitude ≥ 2.8V ,Load resistance≥100k0.
2.5 Real-time data storage function
a. Start and stop records: the latest 1,200 start and stop times and total volume records.
b. Daily records: Dates of the last 920 days, temperature, pressure, standard volume flow and total volume records at zero time.
c. Scheduled time interval records: 920 8-period time, temperature, pressure, standard accumulated flow and total volume records of scheduled time intervals.
2.6 Explosion-proof grade: Explosion-proof Exd II BT4. Intrinsically safe Exia II CT4.
2.7 Protection level: IP65
