Gas Turbine Flow Meter

1. Product Brief Introduction:

The HQ-LWQ gas turbine flow meter adopts advanced microprocessor technology, possessing advantages such as powerful functions, high calculation accuracy, and reliable performance. Its main technical indicators reach the advanced level of similar foreign products. It is an ideal instrument for gas metering in petroleum, chemical, power, metallurgical, industrial and civil boilers, as well as for metering urban natural gas, gas pressure regulating stations, and gas trading. Its working principle is as follows: When gas enters the flow meter, it is first accelerated by a special rectifier. Under the action of the fluid, the turbine overcomes resistance torque and friction torque and begins to rotate. When the torque reaches equilibrium, the speed stabilizes. The turbine speed is proportional to the gas flow rate. The rotating signal disk periodically changes the sensor's magnetic resistance, thereby causing the sensor to output a pulse signal proportional to the flow rate.

2. Product Features:

(1) It adopts imported German precision bearings, ensuring high accuracy, good stability, and a wide rangeability (20:1). Small-diameter flow meters require no lubrication for five years under normal operating conditions, while large-diameter flow meters only require occasional lubrication, making them easy to use.

(2) The carefully designed flow channel structure avoids airflow between the bearings, improving the medium adaptability of the turbine flow meter.

(3) The unique reverse thrust structure and sealing structure design ensure long-term reliable bearing operation.

(4) It uses a magnetoresistive element instead of a magnetic sensing coil, avoiding magnetic attraction, improving detection sensitivity, further reducing the starting flow rate, and enhancing product stability and reliability.

(5) The independent mechanism design ensures good interchangeability and convenient maintenance.

(6) It integrates temperature, pressure, and flow sensors with an intelligent flow totalizer, automatically tracking and correcting the temperature, pressure, and compressibility factor of the measured gas, directly measuring the standard volumetric flow rate and total volume of the gas.

(7) The main performance indicators reach international advanced levels and comply with ISO9951 standards. 8. Employing advanced low-power technology, it can operate with either internal or external power supplies; the internal battery can last for over five years.

(8) The HQ-LWQ model boasts powerful functions, offering four compensation methods, three pulse signal outputs, three historical data recording methods, and two standard current signal outputs.

(9) It can form a network communication system via an RS485 interface, facilitating automated management. The RS485 communication protocol conforms to the MODBUS standard.

(10) The meter head can rotate 180° freely for easy installation.

3. Technical Specifications:

Main Technical Parameters of the HQ-LWQ Gas Turbine Flowmeter
3.1 Model Specifications and Basic Parameters

3.2 Measured Media
Natural gas, city gas, and various other fuel gases, alkanes, and industrial inert gases.
3.3 Operating Conditions
◆ Ambient temperature: -30℃~+60℃; ◆ Medium temperature: -20℃~+80℃;
◆ Atmospheric pressure: 70kPa~106kPa; ◆ Relative humidity: 5%~95%.
3.4 Electrical Performance Indicators
      3.4.1 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 batteries, can be used continuously for more than five years.
      3.4.2 Pulse Output Mode (LWQ type can be selected from one of the following three options)
               a. Working condition pulse signal, opto-isolated amplified output, high level amplitude ≥20V, low level amplitude ≤1V.
               b. Frequency signal proportional to the standard volume flow rate, opto-isolated amplified output, high level amplitude ≥20V, low level amplitude ≤1V.
               c. Calibration pulse signal (compatible with IC card valve controller), high level amplitude ≥2.8V, low level amplitude ≤0.2V, the volume represented by a unit pulse can be set in the range of 0.01m³~10.00m³.
      3.4.3 RS485 Communication (using opto-isolated RS485 communication module), can be directly networked with a host computer or secondary instrument to remotely display current data and historical records.
      3.4.4 4mA~20mA standard current signal (using opto-isolated standard current module); two-wire or three-wire system.
      3.4.5 Control Signal Output
               a. Upper and lower limit alarm signals (UP, LP): Opto-isolated open collector (OC) output, in normal state the OC gate is off, in alarm state the OC gate is on, maximum load current 50mA, working voltage +12VC~+24VDC.

               b. Valve closing alarm (BC) and battery undervoltage alarm (BL) output (for IC card controller); logic gate circuit output, normal output is low level, amplitude ≤0.2V; alarm output is high level, amplitude ≥2.8V, load resistance ≥100kΩ.
3.5 Real-time data storage function
      a. Start/stop record: Records of the most recent 1200 start/stop times and total volume.
      b. Daily record: Records of the date, temperature, pressure, standard volume flow rate, and total volume at midnight for the most recent 920 days.
      c. Timed interval record: 920 records of 8 periods of time, temperature, pressure, standard volume flow rate, and total volume at timed intervals.
3.6 Explosion-proof rating: Flameproof type Exd II BT4. Intrinsically safe type Exia II CT4.
3.7 Protection class: IP65

4. Dimension:

Dimensions of the HQ-LWQ Gas Turbine Flowmeter

5. Selection:

HQ-LWQ Gas Turbine Flowmeter Selection
4.1 Applicable scope
      a. Applications requiring a flow range ratio less than 20:1 (see Table 1), and with high requirements for starting flow rate.
      b. No frequent flow fluctuations with short intervals and large amplitude.
      c. Can measure natural gas, city gas, compressed air, nitrogen, etc.
4.2 Specification determination
Calculate the flow range under working conditions based on the gas supply flow range, medium pressure, and temperature under standard conditions (refer to the selection of vortex flowmeters).
4.3 Pressure loss of the flowmeter
Calculate the maximum pressure loss △Pmax of the flowmeter at the maximum flow rate under working conditions using the following formula (1). The maximum pressure loss of the flowmeter must satisfy condition (2) to ensure normal operation. If the pressure loss does not satisfy formula (2), a larger size should be selected.

       a. Pressure loss can be calculated using the following formula:

P: Gas density under standard conditions (20℃, 101.325 kPa);
△Pomax: Pressure loss at maximum flow rate when the medium is normal dry air (density 1.205 kg/m³) (obtained from Table 1);
Pa: Local atmospheric pressure (kPa); Q: Operating flow rate (m³/h);
Qmax: Maximum operating flow rate of the instrument (m³/h); Pg: Gauge pressure of the medium (kPa).
Pn: Standard atmospheric pressure (101.325 kPa); Tn: Standard temperature (293.15 K);
Tg: Temperature under operating conditions of the medium (273.15 + t); where t is the operating temperature of the medium (°C);
Zn, Zg: Gas compressibility factors under standard and operating conditions, respectively.
       b. The pressure loss should satisfy the condition:
P1 - △Pmax ≥ Lmin................... (2)
Where: P1: Minimum operating pressure of the medium at maximum flow rate;
△Pmax: Maximum pressure loss of the flow meter at maximum flow rate under operating conditions;
PLmin: Minimum inlet pressure required for the gas appliance.

Selection Table

6. Installation:

On-site physical installation photo: