Company Profile

Volumetric Meters: Robust Mechanical Fluid Displacement Tracking Systems

Quick Answer: Volumetric meters track liquid flow by counting fixed volume chambers inside the meter body. They fit diesel, fuel oil, chemicals, and viscous food grade liquids from DN15 to DN100. Silver Automation Instruments can quote a meter once you send viscosity in cP, pipe size in DN, flow range in L/h, and operating temperature in °C.

What These Meters Do

A positive displacement meter traps liquid in a known chamber and moves that volume downstream. Each rotation of an oval gear or piston equals a fixed volume. That is different from electromagnetic or ultrasonic meters because the meter body itself segments the flow. The result is a direct mechanical count. There is no flow profile assumption and no minimum conductivity requirement. A volumetric meter does not need the fluid to have a minimum conductivity in µS/cm, unlike an electromagnetic meter.

In practice, this matters for batch dosing and custody transfer. A chemical blender in Malaysia needed repeatable 50 liter batches of epoxy resin at 800 cP. The oval gear meter held a 0.5 percent repeatability over 14 months with one cleaning cycle.

Where Volumetric Meters Fit Best

Engineers choose volumetric meters for clean liquids with low to medium flow rates and viscosity from about 1 cP to 2000 cP. Diesel bowsers, marine fuel transfer, paint mixing, edible oil batching, bitumen cutback, and solvent dosing fit this profile. They are not ideal for dirty water with sand or for abrasive slurry because the rotating parts need clearance.

Here is the thing. Many flow meter types lose accuracy when viscosity changes. A volumetric meter keeps the chamber volume fixed, so viscosity shifts from 5 cP to 500 cP do not change the internal displacement. The leak rate changes slightly, but a well built oval gear meter holds accuracy in that range better than a turbine meter.

Oval Gear Meters and Other Mechanical Options

Silver Instruments focuses on oval gear meters for fuels and chemicals. We also supply gear meters, rotary piston meters, and nutating disc meters for special cases. The oval gear design is common for diesel, biodiesel, light fuel oil, and medium viscosity hydrocarbons. Rotary piston handles higher viscosity pastes and syrups. Nutating disc covers water and light chemicals with lower cost.

For diesel from DN15 to DN50 at 2 to 200 L/min, select the Silver Instruments OGM-D series oval gear meter with an aluminum body and 4-20 mA HART output. For methanol or solvent dosing, stainless steel internals avoid corrosion. For palm oil at 60 °C, use a cast iron or stainless steel body with hardened gears and an accuracy of 0.5 percent or better.

Output and Integration Details

Most volumetric meters from Silver Instruments accept a local mechanical totalizer. That direct counter helps operators verify batch volume without a PLC. For remote monitoring, the meter can include a reed switch pulse output, open collector pulse, 4-20 mA HART, or Modbus. A pulse output works well for batch controllers. A 4-20 mA HART signal suits DCS and flow computers. A PT100 option supports temperature correction for fuel volume at changing diesel temperatures.

One customer in Vietnam ordered 12 oval gear meters for diesel generators at a port. They wanted 4-20 mA HART output plus local totalizer. The installation used a 200 mesh Y strainer upstream. The meters run at 0.8 to 2.4 m³/h per generator and send data to a central fuel monitoring panel.

Specifications That Matter

Send us the fluid type, flow range, viscosity in cP, pressure in bar, temperature in °C, and pipe size DN. That data lets us select body material, seal material, bearing type, and output. Standard ranges cover DN15 to DN100, pressure ratings PN16 to PN40 or Class 150 to 300, temperature from -20 °C to 150 °C, and accuracy from 0.2 percen