Description

A positive displacement (PD) flowmeter is one of the most accurate instruments available for liquid flow measurement. Unlike velocity-based meters that infer flow from speed, a positive displacement flowmeter physically traps and counts fixed volumes of liquid as they pass through the meter — delivering high accuracy and excellent repeatability even with viscous or variable-flow media.

The PD-O Series uses intermeshing oval gear wheels that rotate with precision inside the meter body. As liquid flows through, it drives the gears and each rotation corresponds to a precisely known volume — making it inherently resistant to flow disturbances and independent of pipe installation conditions. With no straight pipe run requirements and a viscosity range from 0.3 to 20,000 mPa.s, the PD-O is particularly well suited to oil, fuel, and chemical metering applications. Sensors are calibrated in Singapore and are fully traceable to NIST and Singapore’s SPSB standards.

What can it measure?

The PD-O Positive Displacement Flowmeter measures:

• Instantaneous volumetric flow rate
• Accumulated total volume

Typical Applications

The PD-O Series is designed for clean liquids across a wide viscosity range. It is widely used in the following industries and applications:

• Lubricating oil and hydraulic oil — consumption monitoring and dosing
• Diesel and fuel oil — custody transfer, fleet fuelling, and bunker metering
• Chemical dosing — acids, solvents, and process chemicals
• High-viscosity fluids — heavy oils, resins, adhesives, and syrups
• Marine service — fuel flow measurement on vessels (Type X marine variant)
• High-temperature liquids — thermal oils, hot water, and heat transfer fluids (up to +280°C, Type Y)
• Micro-flow applications — small-bore metering for precision dosing (Type V, 6–8 mm)
• Custody transfer and batching — where high accuracy and repeatability are required

Key Advantages

• High accuracy: ±0.2% of reading over a 5:1 range; ±0.5% of reading over a 10:1 range
• Wide viscosity range: 0.3 to 20,000 mPa.s — handles thin solvents through very heavy oils
• No straight pipe runs required — greatly simplifies installation
• Available in cast iron, 316L stainless steel, and cast steel — matched to media and pressure requirements
• High-temperature version (Type Y) rated up to +280°C for thermal oils and hot liquids
• Marine service version (Type X) for vessel and offshore installations
• Micro-flow version (Type V) for precision metering of very small flow rates (2–500 L/h)
• Flameproof certified (Ex d II T4) for use in hazardous areas
• Pulse and 4–20 mA outputs available — integrates easily with PLCs, recorders, and SCADA systems
• Integral LCD display showing instantaneous flow rate and accumulated totals
• Calibrated in Singapore — traceable to USA NIST and Singapore SPSB standards
• Meets European EMC Conformity (EN 61326) and Pressure Equipment Directive (PED)

The PD-O Positive Displacement Flowmeter is sized based on pipe diameter, media viscosity, and the required flow range. Multiple material and flange configurations are available to match your process conditions.

Click here to contact our specialists for advice on selecting the right size and variant for your application.