Oval Gear Flow Meter Solution for Lubricant and Fuel Oil Trade Metering
Addressing the accuracy loss of velocity-type meters, limited turndown and viscosity/temperature sensitivity in trade transfer and batch metering of high-viscosity oils such as lubricants, diesel and fuel oil, this solution uses the oval gear flow meter (positive displacement type) as the core metering element. With 0.5%/0.2% accuracy classes, wide viscosity adaptability and no special upstream/downstream flow requirements, combined with pulse/4-20mA/RS485 remote outputs, explosion-proof certification and temperature compensation, it covers oil loading racks, marine terminals, boiler fuel systems and lubricant dispensing, delivering custody-transfer-grade continuous metering with full data traceability, while RTU networking provides batch reports, inventory accounting and deviation alarms.
Overview
Summary
Addressing the accuracy loss of velocity-type meters, limited turndown and viscosity/temperature sensitivity in trade transfer and batch metering of high-viscosity oils such as lubricants, diesel and fuel oil, this solution uses the oval gear flow meter (positive displacement type) as the core metering element. With 0.5%/0.2% accuracy classes, wide viscosity adaptability and no special upstream/downstream flow requirements, combined with pulse/4-20mA/RS485 remote outputs, explosion-proof certification and temperature compensation, it covers oil loading racks, marine terminals, boiler fuel systems and lubricant dispensing, delivering custody-transfer-grade continuous metering with full data traceability, while RTU networking provides batch reports, inventory accounting and deviation alarms.
Key Advantages
Challenges
- Lubricating oil and heavy fuel oil have high viscosity that varies sharply with temperature; turbine and other velocity meters suffer severe discharge-coefficient drift and often fail to start at low flow, causing long-term fiscal metering errors
- Oil loading at racks and marine terminals is batch-based, requiring good repeatability, preset batching and automatic shut-off; plain indicating meters rely on manual supervision, leading to frequent over/under-filling disputes
- Fuel oils are flammable and explosive — field instruments must hold explosion-proof certification, otherwise they cannot be installed in loading racks, pump rooms and other hazardous areas
- Volume metering is significantly affected by temperature; without temperature compensation, parties settling by mass face deviations of several percent between summer and winter, and trade disputes are hard to arbitrate
- Metering points are scattered across racks, terminals and tank farms; manual reading is delayed and error-prone, leaving inventory reconciliation and batch traceability without continuous, trustworthy data
Results
- The positive displacement principle is insensitive to viscosity — internal slippage decreases with higher viscosity, holding accuracy stable at class 0.5 and reaching class 0.2 for custody transfer, significantly reducing metering disputes
- Batch controller plus solenoid valve enables preset loading with automatic shut-off; over/under-filling eliminated, loading efficiency per shift improved and manual supervision cancelled
- Full explosion-proof certification (Ex db IIC T6 Gb) meets deployment requirements in rack and pump-room hazardous areas, passing safety and fire inspections
- Temperature compensator corrects operating volume flow to standard mass flow; settlement data of both parties align and seasonal temperature-difference deviations are eliminated
- Metering data is centrally uploaded via RTU, automatically generating batch reports, cumulative totals and inventory reconciliation; oil loss investigation now has continuous data support and monthly stocktaking time is greatly shortened
Solution Details
Oval Gear Flow Meter Solution for Lubricant and Fuel Oil Trade Metering
In custody transfer and batch metering of oil products across petroleum storage and transport, chemical, power, marine and transportation industries, media such as lubricating oil, diesel and fuel oil are typically high in viscosity, high in density and sensitive to temperature. Velocity-type meters such as turbine meters suffer discharge-coefficient drift and signal attenuation at low Reynolds numbers, while electromagnetic meters cannot handle non-conductive hydrocarbons at all — neither meets the stringent accuracy and repeatability requirements of fiscal metering. The oval gear flow meter is a classic positive displacement (PD) design: a pair of meshing oval gears alternately rotates inside the metering chamber, dividing the fluid into fixed volumes and discharging them continuously. Its accuracy is essentially unaffected by viscosity changes; in fact, higher viscosity reduces internal slippage and improves accuracy, making it the classic choice for oil metering.
Why Oval Gear Flow Meters Excel in High-Viscosity Oil Metering
This solution is built around the oval gear flow meter, with cast iron, cast steel or stainless steel housings and rotors selected by media viscosity, temperature and pressure. Nominal sizes cover DN10 to DN200, pressure ratings 1.6/2.5 MPa, and media temperature from -20°C to +200°C. Accuracy class 0.5 is standard, with class 0.2 available for custody transfer. The meter supports mechanical register local indication plus pulse, 4-20mA and RS485 (Modbus RTU) remote outputs, and carries explosion-proof certification (Ex db IIC T6 Gb / Ex tb IIIC T85°C Db) for direct installation in hazardous areas such as loading racks, marine loading arms and boiler fuel pump rooms.
Key Technical Specifications of the Oval Gear Flow Meter
DN10–DN200
Nominal Sizes
1.6 / 2.5 MPa
Pressure Ratings
-20°C to +200°C
Media Temperature
Class 0.5 / 0.2
Accuracy
<0.1%
Repeatability
Ex db IIC T6 Gb
Explosion-Proof
Integrated Metering Skid for Fuel Oil Fiscal Metering
For fuel oil fiscal metering, the solution integrates a standard metering skid with upstream/downstream filters, gas eliminator, check valve and control valve; wax-bearing oils that congeal at low temperature are handled with heat tracing and insulation. A temperature compensator continuously corrects volume to mass flow, and a batch controller enables preset loading with automatic shut-off. Metering data is uploaded via RTU to the supervisory platform, automatically generating batch reports, cumulative totals and inventory reconciliation, with instant alarms on deviation or flow loss — satisfying the data traceability requirements of both trading parties.
Product Features of the Oval Gear Flow Meter Solution
- High-accuracy positive displacement metering: oval gear meshing divides fixed volumes, accuracy class 0.5/0.2 selectable, repeatability better than 0.1%, meeting custody transfer requirements
- Wide viscosity and temperature adaptability: media temperature from -20°C to +200°C, accuracy for high-viscosity lubricants and heavy oils improves rather than degrades, with wide turndown
- Multiple housing and rotor materials: cast iron, cast steel and stainless steel selected by media corrosivity, nominal sizes DN10-DN200, pressure ratings 1.6/2.5 MPa
- Diverse signal outputs: mechanical register local indication, pulse, 4-20mA and RS485 (Modbus RTU) remote outputs, compatible with batch controllers, PLCs and RTU networking
- Full-unit explosion-proof certification: Ex db IIC T6 Gb / Ex tb IIIC T85°C Db for direct installation in oil loading racks, marine pump rooms and other hazardous areas
- Integrated metering skid: filter, gas eliminator, temperature compensator and batch controller supplied as a complete set, with heat tracing available for wax-bearing oils — install and commission
? 参考来源
- Oval gear flow meter positive displacement principle and custody transfer metering standards
- Industrial flow measurement guidelines for high-viscosity hydrocarbon media
- Explosion-proof certification standards for hazardous area oil metering installations
Approach
How we implement intelligence into your infrastructure step by step.
Survey and metering class definition
Review oil product types, viscosity-temperature curves, operating pressure/temperature and batch flow ranges; define accuracy requirements (class 0.2/0.5) for fiscal or internal accounting, classify hazardous area zones, and produce a metering point list.
Sizing and metering skid configuration
Select oval gear meter size by media viscosity and flow range, and housing material by corrosivity; configure upstream filter (protecting the gear pair), gas eliminator (removing vapor phase to ensure volumetric accuracy), temperature compensator and batch controller into a standard metering skid.
Installation and piping work
Install horizontally per requirements with specified straight pipe runs and a bypass line; apply heat tracing and insulation for wax-bearing oils, fit check valves on lines with large elevation differences to prevent backflow, and perform cable entry and grounding in hazardous areas per explosion-proof codes.
Calibration, verification and batching commissioning
Verify factory wet-calibration certificates and, where required, submit the meter to legal metrology authorities; configure batch presets and automatic shut-off logic on the batch controller, set deviation alarm thresholds, and complete loading commissioning with the full batch loop.
Data networking and periodic maintenance
Upload pulse/RS485 signals via RTU to the supervisory platform, automatically generating batch reports, cumulative totals and inventory data; establish a maintenance plan for gear-pair wear inspection, filter cleaning and periodic re-verification to keep fiscal metering trustworthy long term.
❓ Related FAQs
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