The LONN-GF gear flow meter is a precision positive displacement flow meter engineered for accurate volumetric measurement of high viscosity liquids. Utilizing advanced oval gear technology, this mechanical flow meter delivers exceptional repeatability across demanding industrial applications including petroleum, chemical processing, hydraulic systems, and fuel monitoring. With robust 316 stainless steel construction and multiple output options, the LONN-GF series ensures reliable performance in harsh operating environments.
Fluid Type: High viscosity liquids, oils, fuels, chemicals
The LONN-GF gear flow meter represents LONNMETER’s commitment to precision flow measurement technology. As a positive displacement flow meter, it operates on the fundamental principle of oval gear displacement—each rotation of the precision-machined gears corresponds to a fixed volume of fluid passing through the measurement chamber.
This mechanical flow meter design eliminates the need for external power in basic configurations while offering electronic output options for modern control systems. The oval gear flow meter architecture is particularly suited for high viscosity flow meter applications where other technologies struggle to maintain accuracy.
The gear flow meter technology has been refined over decades of industrial application, with the oval gear configuration representing the optimal balance between measurement precision, pressure drop characteristics, and long-term reliability. Unlike other positive displacement flow meter designs such as lobed impeller or nutating disc types, the oval gear mechanism provides consistent sealing contact across the full viscosity range, ensuring minimal slip and maximum accuracy.
The LONN-GF positive displacement flow meter employs a pair of precision oval gears housed within a close-tolerance measurement chamber. As fluid enters the meter:
This gear flow meter technology ensures measurement accuracy remains constant regardless of fluid viscosity variations, making it ideal for applications ranging from light diesel to heavy crude oil.
The measurement chamber of the LONN-GF positive displacement flow meter is precision-machined to tight tolerances, typically maintaining clearances of 0.02-0.05mm between gears and housing. These tight clearances minimize internal leakage (slip) while allowing thermal expansion across the operating temperature range. For high viscosity flow meter applications, the increased fluid resistance naturally reduces slip, actually improving measurement accuracy compared to low-viscosity service.
| Parameter | Specification |
|---|---|
| Flow Range | 0.5-150 m³/h (model dependent) |
| Accuracy | ±0.5% of reading (standard), ±0.2% (optional) |
| Repeatability | ±0.2% |
| Viscosity Range | 0.3-1000 cSt (standard), up to 2000 cSt (custom) |
| Temperature | -20°C to +120°C (standard), +200°C (high temp option) |
| Pressure Drop | <0.1 MPa at rated flow |
| Component | Standard Material | Optional Materials |
|---|---|---|
| Meter Body | 316 Stainless Steel | Aluminum Alloy, Hastelloy C |
| Oval Gears | PPS (Polyphenylene Sulfide) | PTFE, 316SS, PEEK |
| Bearings | Hard alloy / Ceramic | Tungsten carbide |
| Shafts | 316 Stainless Steel | Hastelloy C, Titanium |
| Seals | Viton (FKM) | PTFE, EPDM, Kalrez |
| Output Type | Specification |
|---|---|
| Analog | 4-20mA, 2-wire, loop-powered |
| Pulse | Open collector, 24V max, 50mA max |
| Digital | RS485 Modbus RTU, baud rate 9600-115200 |
| Display | Local LCD with totalizer and rate indicator |
| Power | DC 12-24V ±10% / AC 220V ±10% |
| Connection Type | Size Range | Standard |
|---|---|---|
| Flange | DN15-DN100 | ANSI 150LB / DIN PN16 / JIS 10K |
| Thread | 1/2″-4″ NPT / BSP / G | |
| Sanitary | Tri-clamp 1″-3″ | 3A standard |
The oval gear flow meter design delivers volumetric accuracy that remains constant across the entire viscosity range. Unlike turbine or electromagnetic meters, positive displacement flow meter technology measures actual fluid volume displaced, not inferred velocity.
Engineered specifically as a high viscosity flow meter, the LONN-GF maintains specified accuracy even with fluids up to 2000 cSt. This makes it superior to most alternative technologies for heavy oil, bitumen, and polymer applications.
As a mechanical flow meter at its core, the LONN-GF requires no straight pipe runs upstream or downstream. Installation flexibility reduces infrastructure costs and enables retrofit applications where space is constrained.
While functioning as a gear flow meter with mechanical roots, electronic output options include 4-20mA for analog systems, pulse for batching applications, and RS485 Modbus RTU for digital integration with SCADA and DCS platforms.
Multiple material options for gears, bearings, and seals ensure chemical compatibility across diverse applications—from aggressive solvents to food-grade products.
Optimized oval gear profile minimizes pressure loss, reducing pumping costs and enabling installation in low-pressure systems.
| Model | Connection | Flow Range (m³/h) | Max Viscosity (cSt) | Typical Applications |
|---|---|---|---|---|
| LONN-GF-15 | DN15 | 0.5-3 | 1000 | Laboratory, sampling |
| LONN-GF-25 | DN25 | 1-10 | 1000 | Small process lines |
| LONN-GF-40 | DN40 | 3-25 | 1000 | Medium flow applications |
| LONN-GF-50 | DN50 | 5-40 | 1000 | Standard industrial |
| LONN-GF-80 | DN80 | 10-80 | 1000 | High flow transfer |
| LONN-GF-100 | DN100 | 15-150 | 1000 | Pipeline monitoring |
The LONN-GF gear flow meter can be installed in horizontal or vertical orientations. For vertical installation, flow direction should be upward to ensure complete chamber filling and air elimination.
Install 100-mesh filtration upstream to protect precision oval gears from damage. Clean fluids extend maintenance intervals and preserve accuracy.
No straight pipe requirements—positive displacement flow meter technology is immune to flow profile effects. Install directly after valves, pumps, or elbows.
For fluids above 80°C, specify high-temperature bearings and seals. Insulation may be required for viscosity-sensitive applications.
Install isolation valves and bypass loop to enable meter removal for calibration or maintenance without process interruption.
The mechanical flow meter design provides long-term stability. Recommended calibration interval:
| Symptom | Possible Cause | Solution |
|---|---|---|
| Low reading | Worn gears / bypass flow | Inspect gears, check clearances |
| No output | Electrical fault / blockage | Check wiring, verify flow |
| Erratic signal | Air entrainment / cavitation | Check suction conditions |
| High pressure drop | Viscosity too high / overspeed | Verify sizing, reduce flow rate |
Q1: What makes a gear flow meter different from a turbine flow meter? A: A gear flow meter is a positive displacement flow meter that measures actual fluid volume by trapping discrete volumes between rotating gears. Turbine meters infer flow from rotational speed, which varies with viscosity. The oval gear flow meter maintains constant accuracy regardless of viscosity changes.
Q2: Can the LONN-GF measure low viscosity fluids? A: Yes, the LONN-GF gear flow meter accurately measures fluids from 0.3 cSt (light solvents) to 2000 cSt (heavy oils). However, leakage past gears increases at very low viscosities, so sizing consultation is recommended for sub-1 cSt applications.
Q3: Is this suitable for custody transfer applications? A: Absolutely. The positive displacement flow meter design is widely accepted for custody transfer due to its inherent volumetric accuracy and repeatability. Optional ±0.2% accuracy and certified calibration meet most fiscal measurement requirements.
Q4: What maintenance does a mechanical flow meter require? A: The mechanical flow meter core requires minimal maintenance—primarily filter cleaning and periodic calibration verification. With proper filtration, gear wear is minimal even after years of continuous operation.
Q5: Can I use this for food-grade applications? A: Yes. Specify food-grade materials (316SS gears, PTFE seals) and sanitary connections. The LONN-GF high viscosity flow meter is ideal for honey, syrup, and edible oil applications.
Q6: How does temperature affect measurement? A: Temperature primarily affects fluid viscosity. The gear flow meter compensates for viscosity changes automatically. For temperature-varying applications, temperature compensation can be added to convert volume to standard conditions.
Q7: What is the typical lifespan of this flow meter? A: With proper filtration and maintenance, LONN-GF oval gear flow meter units operate 10+ years in industrial environments. Gear wear is the primary aging factor—clean fluids significantly extend service life.
The LONN-GF gear flow meter design and calibration procedures comply with international standards:
For detailed guidance on positive displacement flow meter selection and installation, refer to the Fluid Control Institute (FCI) technical resources.
Contact our technical sales team for pricing and configuration assistance:
Fill out our RFQ form 📧 Email: anna@xalonn.com 📞 Phone: +86-180-9211-4467 🌐 Website: www.smartmeasurer.com
Please provide the following information for accurate quotation:
LONNMETER — Precision Measurement Solutions for Industrial Applications
Please provide your application parameters for a technical assessment and formal quote.