Gas Turbine Flow Meter

Q: Working Principle of a Gas Turbine Flowmeter

The operating principle of a gas turbine flowmeter is based on the direct relationship between the rotational speed of the turbine impeller and the velocity of the fluid. According to basic kinematic principles, the turbine impeller's rotational speed is proportional to the volumetric flow rate of gas passing through it. The core component of a gas turbine flowmeter is a rotating turbine impeller, typically a multi-bladed structure, installed in a pipe. As gas flows through the pipe, the fluid causes the impeller to rotate at a speed proportional to the flow rate. A magnetic material is mounted on the turbine shaft, which interacts with an external magnetic sensor (typically a Hall effect sensor). The sensor measures the turbine impeller's rotational speed and converts it into an electrical signal. By measuring the turbine impeller's rotational speed, the volumetric flow rate of the gas can be calculated. This principle makes gas turbine flowmeters a reliable tool for accurately measuring gas flow. It is important to note that the density of a gas varies with temperature and pressure, affecting the accuracy of flow measurement. Therefore, temperature and pressure compensation is often required when using a gas turbine flowmeter. This compensation can be achieved by using sensors to measure temperature and pressure and then incorporating these parameters into the flow calculation.

Q: Gas Turbine Flow Meter Calibration

We share here the calibration steps of the Sino-Inst gas turbine flowmeter for your reference: The current output calibration affects the performance and accuracy of the meter, and the parameters in this menu do not need to be operated during normal use. Press the SET button (SET) to display the password setting on the LCD, press the shift button (SHT) and the add-key button (INC), set the value to “5000” from left to right, and press the SET button (SET) Enter the user parameter settings. When the current is calibrated and the current output is deviated, the current output can be calibrated through this interface. Calibration requires preparation of a related measuring instrument, such as a multimeter. If there is no measuring instrument, please do not calibrate the current. Calibration current: Select 4mA. At this time, input the measured data of the standard meter into the measured current value, and then press the SET button to select 20mA. At this time, input the measured data of the standard meter and press the (SET) key to confirm. I saw that the current calibration was successful.

A gas turbine flow meter is a velocity-type flow meter that accurately measures gas flow. It is widely used to measure gases such as natural gas, city gas, propane, butane, air, and nitrogen. With high accuracy and excellent repeatability, it is often used for trade measurement and industrial process monitoring.

The density of gas media varies with temperature and pressure. To ensure accurate measurement, a gas turbine flowmeter simultaneously tracks the temperature and pressure of the media being measured, performing temperature and pressure compensation. It also converts the volume flow rate under different operating conditions to that under standard or agreed conditions.

Diameter	DN25～DN300
Accuracy	Class 1.0, class 1.5
Protection	IP65
Explosion proof	ExdIIBT6 (explosion proof type)
Output	Pulse, 4-20mA analog output,RS485 (Modbus-RTU protocol), HART
Medium	ExdIIBT6 (explosion-proof type)

RFQ

Features

High accuracy and good repeatability; wide range ratio up to 1:20;
Low pressure loss and excellent vibration resistance;
Uses high-quality bearings. Low friction and excellent sealing;
Integrates a microprocessor, flow sensor, temperature, and pressure sensor. Directly measures the flow, temperature, and pressure of the gas being measured;
Automatically performs flow tracking compensation and compressibility factor correction calculations;
Provides pulse and analog signal outputs;
Can directly realize centralized computer data collection and real-time management via the RS485 communication interface or GPRS system;
Low power consumption, can be powered by internal batteries or an external power supply;
Provides real-time data storage, preventing data loss during battery replacement or sudden power outages.
Can be used with IC card prepayment systems to facilitate trade settlement.
Explosion-proof grades Exib II BT4 and Exib II BT6.

Specifications

Item	Data
Medium	ExdIIBT6 (explosion-proof type)
Accuracy	Class 1.0, class 1.5
Flange	Standard GB/T 9119-2010
Output	Pulse, 4-20mA analog output, RS485 (Modbus-RTU protocol), HART
Operation condition	Medium temperature: -30℃~+80℃
	Operation temperature: -20℃~+60℃
	Relative humidity: 5%~9%
	Atmospheric pressure: 86kPa~106kPa
Ingress protection	IP65
Explosion proof	ExdIIBT6 (explosion proof type)
Electrical connection	M20*1.5
Diameter and installation	Flange connection DN25-DN300
Power Supply	a. Internal Instrument Power Supply: One 3.6VDC lithium battery, capable of operating normally between 3.1 and 3.6V; b. Internal GPRS Power Supply: One 6.6VDC lithium battery, capable of operating normally between 5.0 and 6.6V; c. External Power Supply: +24VDC ±15%, ripple ≤±5%, suitable for 4-20mA output, pulse output, RS-485, etc.; d. External (solar) GPRS Power Supply: +5VDC to +7VDC.
Power Consumption	External power supply: <1W; internal instrument power supply: average power consumption ≤1mW. Continuous operation for over five years. Internal GPRS power supply: Continuous operation for one to five years, based on the average daily number of calls (2-12).

Flow Range:

Model	Nominal Diameter DN(mm)	Flow Range(m3/h)	Max pressure loss （kPa）	Initial flow （m3/h）	Connection type
LWQ-25	25	2.5-25		1	Flange (thread)
LWQ-25	25	4-40		2
LWQ-40	40	5-50		1.8
LWQ-50	50	6-65	0.7	2.5	Flange
LWQ-50	50	10-100	0.7	2.5
LWQ-80	80	13-250	0.3	6
LWQ-80	80	20-400	0.8	6
LWQ-100	100	20-400	0.2	8
LWQ-100	100	36-650	0.5	8
LWQ-125	125	35-700	0.5	12
LWQ-150	150	32-650	0.4	15
LWQ-150	150	50-1000	1.7	15
LWQ-200	200	80-1600	0.2	35
LWQ-200	200	130-2500	0.9	35
LWQ-250	250	130-2500	0.2	40
LWQ-250	250	200-4000	0.5	50
LWQ-300	300	300-6000	1.5	50

Order Guide

S1–3201							Note
Diameter	DNXX						DN20–DN150 (mm)
Accuracy		A					Class 1.0
		B					Class 1.5
Flow range		S					Standard range
Flow range		E					Extended range
Flange and Housing material			S4				SS304
Flange and Housing material			S6				SS316
Temperature and pressure compensation				A			With temp. and pressure compensation
Temperature and pressure compensation				N			Without temp. and pressure compensation
Power supply					1		24VDC
Power supply					2		Lithium battery
Output					A		4-20mA
					M		Pulse
					R		RS485
					H		HART
Explosion Proof					BT		Exd II BT6
					CT		Exia II CT4
					NA		None
Connection						THM	Male Thread; Available from DN20-DN50
						THF	Female Thread; Available from DN20-DN50
						DXX	DN16:DIN PN16 Flange;
						AXX	A15:ANSI 150# Flange;
						JXX	J10:JIS 10K Flange;

Note for type selection:

Gas turbine flow meter is mainly applicable for intermediate and low velocity gas without impurities. Please install a filter to ensure medium cleaning and note that the product cannot measure moisture. The product is not suitable for liquids and steam.

Type selection process:

Select the main model and structure first, then ensure the other specifications according to requirements.

i.e., main model + nominal diameter + accuracy + installation method + flange and housing material + temperature and pressure compensation + power supply + output.

Featured Applications of Gas Turbine Flowmeters

Natural Gas

As a clean energy source, natural gas holds a vital position in both industrial and civilian sectors. Efficient flow measurement is essential for natural gas trade measurement, transportation, and use. Monitoring pressure and temperature is also essential.

Advantages of using a gas turbine flowmeter for natural gas measurement:

Gas turbine flowmeters offer significant advantages in accuracy, repeatability, zero drift, and rangeability. Their bearings and guide vanes are specially designed to reduce wear, ensuring reliable measurement under challenging conditions.

Gas turbine flowmeters integrate a microprocessor, flow sensor, and high-precision temperature and pressure sensors to directly measure gas flow, temperature, and pressure. They also automatically perform flow tracking compensation and compressibility factor correction.

Other commonly used natural gas flowmeters include gas turbine (Roots) flowmeters and vortex flowmeters.

Waste Gas Measurement

Renewable resource development is a key path to achieving sustainable development, encompassing multiple sectors, including waste gas recovery, biogas utilization, wastewater treatment, and cogeneration. Accurate gas flow measurement in these processes is crucial for optimizing energy recovery and utilization efficiency, improving treatment outcomes, and ensuring efficient system operation.

In a large-scale waste gas recovery project, precise flow measurement from the waste gas source to the recovery system is required to ensure efficient operation and regulatory compliance.

Gas turbine flowmeters, with their high-precision measurement capabilities, accurately record waste gas flow and transmit this data in real time to a central control system for analysis. Operators use this real-time flow data to adjust waste gas recovery and treatment parameters, optimizing system efficiency, increasing energy recovery and utilization, and reducing operating costs.

Techincal Support

The operating principle of a gas turbine flowmeter is based on the direct relationship between the rotational speed of the turbine impeller and the velocity of the fluid. According to basic kinematic principles, the turbine impeller’s rotational speed is proportional to the volumetric flow rate of gas passing through it.

The core component of a gas turbine flowmeter is a rotating turbine impeller, typically a multi-bladed structure, installed in a pipe. As gas flows through the pipe, the fluid causes the impeller to rotate at a speed proportional to the flow rate. A magnetic material is mounted on the turbine shaft, which interacts with an external magnetic sensor (typically a Hall effect sensor). The sensor measures the turbine impeller’s rotational speed and converts it into an electrical signal.

By measuring the turbine impeller’s rotational speed, the volumetric flow rate of the gas can be calculated. This principle makes gas turbine flowmeters a reliable tool for accurately measuring gas flow.

It is important to note that the density of a gas varies with temperature and pressure, affecting the accuracy of flow measurement. Therefore, temperature and pressure compensation is often required when using a gas turbine flowmeter. This compensation can be achieved by using sensors to measure temperature and pressure and then incorporating these parameters into the flow calculation.

We share here the calibration steps of the Sino-Inst gas turbine flowmeter for your reference:

The current output calibration affects the performance and accuracy of the meter, and the parameters in this menu do not need to be operated during normal use.

Press the SET button (SET) to display the password setting on the LCD, press the shift button (SHT) and the add-key button (INC), set the value to “5000” from left to right, and press the SET button (SET) Enter the user parameter settings.

When the current is calibrated and the current output is deviated, the current output can be calibrated through this interface. Calibration requires preparation of a related measuring instrument, such as a multimeter.

If there is no measuring instrument, please do not calibrate the current.

Calibration current: Select 4mA. At this time, input the measured data of the standard meter into the measured current value, and then press the SET button to select 20mA. At this time, input the measured data of the standard meter and press the (SET) key to confirm. I saw that the current calibration was successful.

SI-3201 GAS Turbine Flow Meter