Roots Type Liquid Flowmeter
Roots-type liquid flowmeter (also called lobe flowmeter) is a positive displacement flow meter that uses two precisely machined rotating lobes (resembling figure-8 or peanut shapes) to measure liquid flow.
Roots meters handle very high flow rates of low-viscosity liquids with extremely low pressure drop. They are perfect for fuel terminals, water distribution, and bulk liquid transfer.
| Product Standard | JB/T9242-2015 (General Technical Specifications for Positive Displacement Flowmeters) |
| Explosion-proof Mark | Exd II CT6 |
| Flange Standard | DN, ANSI, JIS |
| Protection Class | IP66 |
Related Products
Liquid Coriolis Mass Flow Meter
Electromagnetic Flow Meter for Corrosive Liquid
Key Features of Liquid Roots Flow Meters
- High Flow Capacity Handles extremely high flow rates from 50 to 10,000+ L/min, significantly exceeding the capacity of oval gear and other PD meter types.
- Extremely Low Pressure Drop Minimal flow resistance reduces pumping energy costs and enables gravity-fed system applications where pressure loss is critical.
- Precision Measurement Delivers accuracy of ±0.2% to ±0.5% with excellent repeatability, ensuring reliable volumetric measurement for custody transfer and billing applications.
- Low-Viscosity Optimization Specifically designed for thin liquids like water, gasoline, diesel, solvents, and light chemicals (typically <5 cP for optimal performance).
- Robust Construction Available in cast iron, ductile iron, or stainless steel bodies with hardened steel or stainless steel rotors for long service life.
- Wide Temperature Range Operates from -20°C to +120°C (standard models), with high-temperature versions available for specialized applications.
- Multiple Output Options Configurable with mechanical registers, digital displays, pulse outputs, 4-20mA analog signals, and digital communication protocols (Modbus, HART).
- Large Pipe Sizes Available in DN50 to DN300+ (2″ to 12″+) for high-volume transfer applications.
- Bi-directional Measurement Measures flow in both directions, useful for loading/unloading operations and reversible transfer systems.
- Minimal Maintenance Simple two-rotor design with few moving parts and no complex gearing reduces maintenance requirements and extends service intervals.
Flow Range:
Flow ranges vary depending on fluid viscosity and required accuracy grade. Flow Range Unit: m³/h
| Nominal Diameter (mm) | Fluid Viscosity (mPa·s) | |||||
| 2.0~150 | 0.6~2.0 | 2.0~150 | 0.6~2.0 | 2.0~150 | 0.6~2.0 | |
| 25 | 0.6~6 | 1.2~6 | 1.2~6 | 1.5~6 | 1.5~6 | 2~6 |
| 40 | 1.6~16 | 3.2~16 | 3.2~16 | 4~16 | 4~16 | 5~16 |
| 50 | 2.5~25 | 5~25 | 5~25 | 6~25 | 6~25 | 8~25 |
| 80 | 6~60 | 12~60 | 12~60 | 15~60 | 15~60 | 20~60 |
| 100 | 10~100 | 20~100 | 20~100 | 25~100 | 25~100 | 33~100 |
| 150 | 25~250 | 50~250 | 50~250 | 60~250 | 60~250 | 80~250 |
| Accuracy Grade | 0.5 | 0.3 | 0.2 | |||
Model Selection:
| tem | Code | Description |
| Series Type | LL | Liquid Roots Flowmeter |
| Shell Material | A | Cast iron |
| E | Cast steel | |
| L | Aluminum alloy | |
| Rotor Material | L | Aluminum alloy |
| Nominal Diameter | 25~150 | Flow meter sizes from DN 25mm to DN150mm |
| Pressure Rating | .06 | 0.6 MPa |
| .1 | 1.0 MPa | |
| .2 | 1.6 MPa | |
| .3 | 2.5 MPa | |
| .4 | 4.0 MPa | |
| Register | A | Mechanical pointer, 6 digits totalizer, no return to zero |
| A6 | Mechanical pointer, 6 digits totalizer, return to zero | |
| BELZ-0 | Digital indicator, instant and totalized flow, battery power, no output, Explosion proof | |
| BELZ-1 | Digital indicator, instant and totalized flow, 24V DC, Pulse output, 3-wire, Explosion proof | |
| BELZ-2 | Digital indicator, instant and totalized flow, 24V DC, 4-20mA output, 2-wire, Explosion proof | |
| BELZ-3 | Digital indicator, instant and totalized flow, 24V DC, 4-20mA output, 4-wire, Explosion proof | |
| BELZ-4 | Digital indicator, instant and totalized flow, 24V DC, 4-20mA output, Hart, Explosion proof | |
| Transmitter | BGF-I | Only for A or A6, Pulse output, 3-wire, Explosion proof 12V DC |
| BGF-II | Only for A or A6, Pulse output, 3-wire, Explosion proof 24V DC | |
| BMF | Only for A or A6, 4-20mA output, Explosion proof 24V DC power supply | |
| Accuracy | J | 0.2% |
| J2 | 0.3% |
Applications of Root Type Liquid flowmeter
Fuel Terminals & Loading Racks High-speed loading and unloading of gasoline, diesel, and jet fuel at distribution terminals. Accurate custody transfer measurement for truck and railcar loading operations.
Water Distribution Systems Municipal and industrial water metering where minimal pressure drop is essential. Large diameter pipeline measurement for water treatment plants and distribution networks.
Petroleum & Chemical Bulk Transfer Pipeline metering of light petroleum products, solvents, and chemicals. Tank-to-tank transfers and storage facility inventory control with high accuracy.
Aviation Refueling High-volume jet fuel dispensing at airports and military bases. Rapid aircraft refueling with precise measurement and low pressure loss.
Marine Bunkering Ship refueling operations requiring high flow rates and accurate measurement. Suitable for diesel, marine gas oil, and low-viscosity bunker fuels.
Industrial Process Applications Cooling water circuits, process water metering, and large-scale chemical dosing systems. Any application requiring high-volume, low-viscosity liquid measurement.
