12-Inch Positive Displacement Flow Meter: Precision, Durability, and Performance

12-Inch (DN300) Helical Gear Positive Displacement Flow Meter for Oil & Fuel

While smaller positive displacement (PD) flow meters such as 2-inch, 3-inch, or 4-inch models are common, a 12-inch (DN300) positive displacement flow meter is far harder to source. Only a few manufacturers can build large-capacity PD meters with reliable performance. Silver Automation Instruments is one of them. Our 12-inch helical gear flow meter is engineered for fuel, oil, crude oil, and diesel, delivering accurate volumetric measurement for demanding industrial applications.

Working Principle: How a Helical Gear PD Flow Meter Measures Flow

A positive displacement (PD) flow meter divides fluid into fixed, repeatable volumes. In a helical gear flow meter, two precisely machined helical rotors spin within a measuring chamber as the liquid passes through. Each full rotation displaces a fixed base volume, so the total number of rotations is directly proportional to the volumetric flow.

Because the rotors do not contact each other or the chamber walls, mechanical wear is minimal and service life is extended. The helical profile ensures smooth, low-pulsation flow, reducing vibration/pressure ripple that could affect downstream instruments or control valves. This yields lower noise, more stable signals, and precise data for automated control—ideal for oil and fuel metering where stable readings and long-term repeatability are critical.

Key Features & Advantages

1. High accuracy & repeatability — Up to ±0.2% accuracy with excellent repeatability; suitable for custody transfer and process control.
2. Wide viscosity capability — Handles liquids up to 3500 cP, covering heavy oils/bitumen/lubricants (oval gear meters typically suit lower viscosity; selection depends on process conditions).
3. Low pressure drop & low noise — Helical gears minimize flow resistance and mechanical vibration for quieter, stable readings.
4. Temperature & pressure resistance — Up to 250 °C (with heating jackets) and pressure ratings up to 900 psig (model-dependent).
5. Flexible outputs — Mechanical register or electronic transmitter with pulse, 4–20 mA, MODBUS RTU or HART.
6. Robust materials — Stainless steel, cast steel, or aluminum alloy (by model) to fit different fluids, corrosion levels, and budgets.
7. Easy maintenance & calibration — Simple mechanism and precision machining reduce downtime and lifecycle cost.

These strengths make the 12-inch PD meter a versatile choice for petroleum refining, chemical processing, power generation, marine fueling, and bulk liquid logistics.

12-Inch Mechanical Flow Meter for Fuel & Oil Measurement

A 12-inch mechanical flow meter is ideal for high-volume transfer of diesel, fuel oil, crude oil, and other hydrocarbons. Its helical gear chamber provides smooth, low-pulsation measurement even at high rates (up to ~900 m³/h, viscosity-dependent). The mechanical register gives a direct visual display—reliable for sites lacking external power. Built with carbon steel and stainless steel, the meter is engineered for long life in harsh environments, from loading terminals to fuel depots and oil distribution systems.

Applications Across Industries

• Oil flow measurement in pipelines, terminals, and refineries
• Fuel metering for diesel, kerosene, aviation fuels
• Chemical batching & blending (viscous liquids, heating jacket options)
• Lubricant & hydraulic oil monitoring
• Custody transfer between suppliers and end users
• Bitumen/asphalt with jacketed versions

Construction & Materials

Each unit comprises a precision flow sensor, an accuracy adjuster, a mechanical or digital register, and a signal transmitter. Timing gears are located outside the measuring chamber to synchronize the rotors without internal contact. Optional heating jackets (hot water/oil/steam, typically ≤200 °C) help keep viscous liquids at optimal conditions without damaging the meter body. Available pressure classes include PN16, PN25, PN40, and 6.3 MPa (model-specific). Single-body or double-body designs are available to match flow and installation needs.

Installation Guidelines

• Install an upstream filter to prevent debris ingress.
• Use a gas separator if entrained gas/bubbles are present.
• Match flow direction to the arrow on the meter body.
• Avoid rapid valve changes that cause pressure shocks.
• Operate at 40–80% of maximum flow for best accuracy.
• Provide a bypass line if continuous measurement is required during maintenance.
• Avoid water calibration for cast-iron/cast-steel meters unless specifically approved.

Technical Performance Summary

• Size: 12-inch (DN300) — designed for DN300 pipelines to measure large liquid flow rates.
• Flow range: up to ~800–900 m³/h (typical; depends on viscosity and configuration).
• Accuracy: ±0.2% or ±0.5% (model/configuration dependent).
• Repeatability: ≤ 1/3 of basic error.
• Temperature: −41 °C to +250 °C (with high-temperature radiator/jacket options).
• Viscosity capability: up to 3500 cP.
• Outputs: Pulse, 4–20 mA, HART, or mechanical display.
• Pressure rating: up to 6.3 MPa (model-specific).
• Explosion-proof: options for hazardous areas.

Viscosity vs. Typical Flow (12-Inch)

The following values are examples based on common applications and do not represent all industry conditions.

Why Choose Silver Automation Instruments

As an experienced flow meter manufacturer in China, Silver Automation Instruments supplies positive displacement, turbine, Coriolis mass, and magnetic flow meters worldwide. We focus on cost-effective, high-performance products with responsive technical support. Every meter is tested prior to shipment, and our quality system complies with international standards (e.g., ISO 9001, CE).

Conclusion

The 12-inch (DN300) helical gear PD flow meter from Silver Automation Instruments delivers accurate, stable volumetric measurement for oil, fuel, and other bulk liquid applications. With rugged materials, flexible I/O, jacket options, and simplified servicing, it offers the reliability and total cost of ownership industrial users expect.

Whether you manage an oil distribution network, a fuel storage facility, or a chemical transfer line, our 12-inch PD meter ensures every drop counts—accurately and efficiently.

FAQ — 12-Inch (DN300) Positive Displacement Flow Meter

1) What is the flange-to-flange (face-to-face) length of a 12-inch PD flow meter?

The typical face-to-face length for a 12-inch (DN300) positive displacement flow meter is 800 mm.

2) How much does a 12-inch positive displacement flow meter weigh?

The approximate net weight is about 890 kg. Final shipping weight may vary with options and materials.

3) Does a 12-inch PD flow meter require straight run (straight pipe) for installation?

No straight run is required. Unlike many velocity-type meters, a helical gear PD flow meter does not need upstream/downstream straight lengths.

4) Can the 12-inch PD meter use a mechanical register (no external power)?

Yes. A mechanical register is available for power-free local indication. Electronic transmitters are also optional.

5) Are pulse, 4–20 mA, or MODBUS RTU outputs available?

Yes. We can provide pulse, 4–20 mA, and MODBUS RTU outputs. Please specify your I/O requirements when ordering.

6) Can you provide a pressure drop (ΔP) curve for the 12-inch PD flow meter?

Yes. Pressure drop charts/curves can be supplied upon request to match your viscosity, flow rate, and fluid temperature. Below is pressure loss curve for your reference.