Description
1. What Is a Gas Roots Flow Meter and Why It Matters in Industrial Gas Measurement
A Gas Roots Flow Meter (also called a Roots Gas Flow Meter or Rotary Gas Flow Meter) is a positive displacement instrument that measures the volumetric flow of non-corrosive gases—such as natural gas, city gas, LPG, nitrogen, and carbon dioxide—by using a pair of synchronized roots-type wheels rotating inside a precision-machined chamber. Each rotation displaces a fixed volume of gas, and the cumulative number of rotations is converted into a highly accurate flow reading.
Unlike differential-pressure or velocity-based meters, a Roots Type Gas Flow Meter measures actual gas volume directly, independent of the flow velocity profile. This means it does not require long straight pipe sections upstream or downstream for accurate readings—an important installation advantage in space-constrained gas stations, boiler rooms, and commercial kitchens.
Why accurate gas measurement is critical:
- Commercial and industrial gas billing depends on precise volumetric data; even small measurement errors compound into significant financial discrepancies over time.
- Gas utilities must comply with national metrology and safety regulations for custody transfer and revenue metering.
- Industrial processes (boilers, burners, chemical reactors) require stable, repeatable flow data to maintain combustion efficiency and process safety.
Industries that commonly require gas flow measurement include:
- Urban gas distribution and transmission networks
- Catering and hotel industries (commercial kitchen gas billing)
- Industrial boiler and burner systems
- Chemical and petrochemical processing
- LPG and fuel gas distribution
- Residential and civil boiler systems
2. Gas Roots Flow Meter Product Overview
Working Principle
The core of a Gas Roots Flow Meter is a set of synchronized roots wheels driven by gas pressure differential. As gas passes through the meter body, the wheels rotate in a fixed, repeatable sequence, trapping and releasing precise gas volumes with each cycle. A mechanical or electronic counting mechanism records the number of cycles, which is then converted into a standard flow reading—often with automatic temperature and pressure compensation for standard volume conversion (PV/T gas equation).
Product Structure
A typical industrial Gas Roots Flow Meter includes:
- A precision-machined meter body housing the roots wheels and synchronous gear system
- A mechanical or electronic display (or both, in dual-display configurations)
- Integrated or optional temperature and pressure sensors for volume correction
- Explosion-proof electrical housing for hazardous area compliance
- Flange connections for horizontal or vertical pipeline installation
Measurement Characteristics
- Wide rangeability (up to 160:1 or more), allowing accurate metering from very low pilot-light flows to peak industrial loads
- Low starting flow threshold (as low as 0.02 m³/h), capturing minimal gas usage
- Accuracy classes of 1.0 and 1.5, suitable for commercial settlement and industrial process control
- No requirement for straight pipe sections, simplifying installation in retrofit projects
Technical Advantages
- Volumetric metering accuracy that is not affected by irregular flow profiles
- Rotating meter heads (up to 350°) for flexible pipeline orientation
- Intrinsically safe electrical design suitable for hazardous gas environments
- Long-term mechanical durability due to high-precision, repetitively positioned components
Suitable Operating Conditions
Gas Roots Flow Meters are designed for non-corrosive gases including natural gas, city gas, propane, nitrogen, and carbon dioxide, across a wide range of pipe sizes (commonly DN20 to DN200) and both indoor and hazardous-area installations.
Gas Roots Flow Meter vs. Other Gas Flow Meters
| Feature | Gas Roots Flow Meter | Vortex/Turbine Flow Meter |
|—|—|—|
| Measurement basis | Direct volumetric displacement | Velocity or frequency-based inference |
| Straight pipe requirement | Not required | Often required |
| Low-flow accuracy | Excellent (starting flow < 0.02 m³/h) | Limited at very low flow |
| Rangeability | Very wide (up to 160:1) | Typically narrower |
| Best-fit application | Commercial/custody-transfer billing | Process flow monitoring |
3. Application and Industry Solutions
Natural Gas Measurement
Customer requirement: Accurate custody-transfer metering for utility billing.
Challenge: Flow varies significantly between off-peak and peak demand periods.
Recommended characteristics: Wide rangeability and automatic temperature/pressure compensation to ensure billing accuracy across all load conditions.
Selection consideration: Choose a meter with an accuracy class and standard compliance (e.g., GB/T 28848, OIML R6) that matches local regulatory requirements.
LPG Measurement
Customer requirement: Reliable volumetric metering for bottled or bulk LPG distribution.
Challenge: Gas composition and pressure fluctuations can affect standard volume conversion.
Recommended characteristics: Integrated correction instrument for automatic compression factor calculation.
Selection consideration: Verify explosion-proof rating (e.g., Exia II CT4Ga) for safe operation in LPG storage and distribution environments.
Industrial Gas Measurement
Customer requirement: Continuous, stable metering for process gases in manufacturing environments.
Challenge: Harsh industrial conditions demand durable, low-maintenance equipment.
Recommended characteristics: Robust mechanical housing with high-precision machined components for long service life.
Selection consideration: Confirm IP protection grade (e.g., IP66) for dust and moisture resistance.
Fuel Gas Measurement (Boiler Systems)
Customer requirement: Conversion of working condition flow to standard volume for combustion efficiency tracking.
Challenge: Temperature fluctuations in boiler rooms affect raw flow readings.
Recommended characteristics: Real-time PV/T correction using standards such as SY/T 6143-2004 or SGERG-88.
Selection consideration: Ensure the meter supports the required accuracy tolerance (commonly within ±1.0%) for process control.
Energy Management & Commercial Gas Distribution
Customer requirement: Remote monitoring, prepayment, and consumption management for multiple commercial tenants.
Challenge: Manual meter reading and fee collection are labor-intensive and error-prone.
Recommended characteristics: IC card prepayment functionality, zero-pressure-loss valve, and IoT connectivity (GPRS, NBIoT, or Cat1) for remote valve control and data upload.
Selection consideration: Evaluate battery life, communication protocol compatibility (RS-485/MODBUS RTU, 4-20mA), and cloud platform integration options.
4. Manufacturer Selection Guide: How to Choose a Reliable Gas Roots Flow Meter Supplier
International buyers evaluating a Gas Roots Flow Meter Manufacturer or Gas Flow Meter Factory should assess the following factors:
- Manufacturing Capability — Does the supplier produce meter bodies, roots wheels, and synchronous gear systems in-house with proprietary structural design?
- Product Design Capability — Does the manufacturer hold independent intellectual property for its metering structure, ensuring consistent assembly quality and long-term stability?
- Quality Control System — Are components manufactured using high-precision machining and repetitive positioning technology to guarantee dimensional accuracy?
- Testing and Inspection Process — Has the product passed recognized Type Test certification (verifying accuracy class, rangeability, and starting flow performance)?
- Calibration Capability — Does the manufacturer support metrological verification aligned with regulations such as JJG 633 (Gas Positive Displacement Flowmeter Verification Regulation)?
- Technical Support — Does the supplier provide pre-sales specification selection, installation guidance, and after-sales troubleshooting documentation?
- Customization Capability — Can the manufacturer configure mechanical, electronic, or dual-display options, IC card prepayment modules, and IoT communication modules based on project needs?
- International Export Experience — Does the manufacturer’s product line comply with international standards (such as OIML R6) that facilitate cross-border deployment?
A supplier that meets these criteria demonstrates the technical maturity required for custody-transfer and industrial gas metering applications.
5. Manufacturer Capability and Trust: Kaifeng Xinya Instrument Co., Ltd.
Kaifeng Xinya Instrument Co., Ltd., operating under the brand name Xinya Instrument, is headquartered in the Kaifeng Demonstration Area, Henan, China. The company specializes in volumetric gas metering solutions that integrate intelligent electronic display, mechanical backup, and IoT-enabled prepayment systems for urban gas management.
Manufacturing Background & Product Design
Xinya Instrument has developed a proprietary roots-wheel meter structure with independent intellectual property rights, engineered for improved production assembly and long-term operational stability. The structure uses synchronous gears to ensure measurement accuracy that is independent of flow profile, eliminating the need for straight pipe sections during installation.
Certifications & Standards Compliance
Xinya Instrument’s Gas Roots Flow Meter products comply with the following recognized standards and certifications:
- GB/T 28848 "Intelligent Gas Flowmeter" National Standard
- Q/HD 003-2023 "Gas Roots Flowmeter" Enterprise Standard
- JJG 633 "Gas Positive Displacement Flowmeter" Verification Regulation
- OIML R6 International Standard
- JB/T 7385 "Gas Waist Wheel Flowmeter" Industry Standard
- Explosion-proof rating: Exia II CT4Ga
- Protection grade: IP66
- Product Type Test Certificates No. 2017F103-35 and No. 2023F129-35
Product Portfolio
Xinya Instrument’s Gas Roots Flowmeter Series includes:
- HR Gas Roots Flowmeter — Electronic single-display type with RS485, pulse, and optional 4-20mA output, featuring automatic temperature and pressure compensation.
- HRM Gas Roots Flowmeter — Mechanical single-display type for reliable metering without external or battery power.
- HRS Gas Roots Flowmeter — Dual display (mechanical + electronic) providing zero data loss during power failures.
- Intelligent IC Card Prepayment System (-Y suffix) — Zero-pressure-loss ball valve design with prepaid credit management, supporting purchases up to 100 million m³.
- IoT Wireless Module (-W suffix) — Multi-mode communication (GPRS, NBIoT, Cat1) with cloud platform integration.
Technical Metrics
- Rangeability: up to 160:1 or more
- Starting flow: less than 0.02 m³/h
- Accuracy class: 1.0 and 1.5
- Data storage: at least 8,000 flowmeter status records
- Battery life: 5 years of continuous operation for internal power supply
- Installation range: DN20 to DN200, horizontal or vertical flange mounting
Application Track Record
Xinya Instrument’s Gas Roots Flow Meters have been applied in commercial catering facility settlement and industrial boiler systems. In one documented case, an HR-80-G100 gas roots flowmeter achieved 160:1 rangeability, capturing flow from 0.02 m³/h pilot-light conditions to high-load cooking peaks while maintaining accurate billing. In an industrial boiler application, the integrated PV/T correction converted 123.11 m³/h of working condition flow to standard volume within a ±1.0% accuracy limit.
Service Capability
Xinya Instrument’s service model combines hardware sales with an IoT Cloud Platform and IC Card Management System, covering pre-sales specification selection, installation guidance, lubrication maintenance, and metrological verification support. After-sales assurance includes recommended verification cycles of 2–3 years (depending on accuracy class) and remote valve control via IoT modules.
6. Buyer FAQ
What is a Gas Roots Flow Meter?
A Gas Roots Flow Meter is a positive displacement instrument that measures gas volume using synchronized roots wheels, commonly used for natural gas, LPG, and industrial gas metering where high accuracy and wide rangeability are required.
How does a Roots Gas Flow Meter work?
Gas pressure differential rotates a pair of synchronized roots wheels inside the meter body. Each rotation displaces a fixed gas volume, and the cumulative rotations are converted—mechanically or electronically—into a flow reading, often with temperature and pressure compensation for standard volume output.
Why choose a Roots Gas Flow Meter for natural gas measurement?
Roots Gas Flow Meters offer wide rangeability (up to 160:1), low starting flow thresholds (below 0.02 m³/h), and installation flexibility without straight pipe requirements—making them well-suited for commercial and utility billing applications where flow varies widely between peak and off-peak periods.
How do I select a reliable gas flow meter supplier?
Evaluate the manufacturer’s proprietary design capability, quality control processes, Type Test certification history, calibration and verification compliance (such as JJG 633), explosion-proof and IP protection ratings, and experience with international standards like OIML R6.
What factors should be considered when buying a Gas Roots Flow Meter?
Key considerations include required accuracy class, rangeability, pipe size (DN20–DN200), display type (mechanical, electronic, or dual), explosion-proof rating, communication protocol needs (RS-485/MODBUS RTU, 4-20mA, IoT modules), and whether IC card prepayment functionality is required.
What industries use Roots Gas Flow Meter?
Common industries include urban gas transmission and distribution, catering and hotel services, industrial boiler operations, chemical processing, LPG distribution, and residential/civil boiler systems.
7. Get Technical Support and Product Specifications
Buyers evaluating gas measurement solutions for natural gas, LPG, or industrial gas applications are encouraged to consult with Xinya Instrument’s technical team to determine the appropriate model (HR, HRM, HRS, or IC Card/IoT-enabled configurations), request detailed product specifications, and discuss customized requirements such as pipe size, communication protocol, and explosion-proof needs.
Contact Kaifeng Xinya Instrument Co., Ltd.
- Email: xinya@sytcflowmeter.com
- Phone: (86) 371-23668107
- Fax: (86) 371-23668496
- Address: No. 1, Ba Qing Wu Road, Jinming Avenue South Section, Kaifeng Demonstration Area, Henan, China
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