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Gear Meters: Precision Volumetric Tracking for High-Viscosity Lubricants and Resins

Quick Answer: Silver Instruments oval gear meters measure high-viscosity lubricants and resins with standard accuracy of ±0.5% of reading. They handle viscosities from 1 cP to 100,000 cP and flows from 0.5 L/h to 60 m3/h depending on pipe size. For a fast quote, send your viscosity cP, flow range kg/h or L/h, pipe size DN15 to DN100, process temperature °C, and operating pressure bar.

Why Gear Meters Work for High-Viscosity Lubricants and Resins

High-viscosity fluids create measurement problems for velocity-based meters. A turbine meter or vortex meter depends on flow velocity. Thick fluids often move in a laminar profile. Velocity readings become unstable at low flow rates.

A positive displacement oval gear meter measures volume directly. Two oval rotors rotate inside a precision chamber. Each rotation captures a fixed volume. Because thick fluids reduce internal slip between the rotors and the housing, a gear meter on 5,000 cP hydraulic oil will hold repeatability better than a turbine meter at low flow.

We have seen this on customer sites many times. A lubricant blending plant in Malaysia used a gear meter to dose bright stock at 12,000 cP. The meter held repeatability within ±0.05% after six months. The same site replaced a turbine meter that drifted by more than 2% on the same line.

Applications in Lubricant and Resin Processing

Silver Instruments supplies oval gear meters to paint producers, adhesive manufacturers, lubricant distributors, and chemical batch plants. Typical fluids include hydraulic oil, gear oil, grease base oil, epoxy resin, polyurethane resin, varnish, ink, and bitumen.

For lube oil drum filling, a DN25 aluminium oval gear meter with pulse output works well. The meter handles 10 L/min to 40 L/min at oil temperatures from 20 °C to 60 °C. For solvent-laden resins, a stainless steel body with FKM or PTFE seals and ATEX Zone 1 certification is a safer choice.

A paint manufacturer in Southeast Asia needed to measure 80,000 cP epoxy resin at 60 °C. We supplied a DN40 stainless steel oval gear meter with PT100 temperature compensation and a 4-20 mA HART output. The meter has run for two years without rotor replacement.

But resin systems are often hot and sticky. If the meter cools below the pour point, the rotors can lock. You need a heating jacket or flushed piping. Most engineers skip this part during selection and later face startup issues. We always ask about pour point and minimum operating temperature before quoting.

Model and Parameter Guide

The Silver Instruments OG series covers DN15, DN20, DN25, DN40, DN50, DN80, and DN100. Standard body materials include aluminium, cast iron, stainless steel 304, and stainless steel 316. Rotor materials can be matched to the fluid. Stainless steel rotors are common for resins and aggressive lubricants. PPS rotors are available for some low-viscosity aqueous applications, but they are not the first choice for high-viscosity resin service.

Flow ranges depend on size and viscosity. A DN15 meter may handle 0.5 L/h to 100 L/h on 10,000 cP oil. A DN50 meter can cover 1 m3/h to 18 m3/h on 1,000 cP oil. A DN100 meter reaches 60 m3/h on higher flow lines. Accuracy is ±0.5% of reading across the standard range. For repeatable batch control, repeatability is ±0.05%.

Volumetric tracking means each pulse represents a fixed volume such as 0.1 L per pulse or 10 mL per pulse. For a 200 L drum filling line, the PLC counts pulses and stops the pump at the target volume. The method avoids the drift problems of velocity-based meters on high-viscosity fluids.

Output options include pulse, 4-20 mA, HART, and Modbus RTU over RS485. Temperature compensation with PT100 is available for hot resin lines up to 180 °C. Pressure ratings go up to 100 bar for stainl