Helical Rotor Flowmeters and Industrial Applications

Helical rotor flowmeters are a special type of positive displacement flowmeter. They operate based on the principle of axial helical rotors being rotated by the fluid flow. Each rotation of the rotor represents a fixed and known volume, ensuring high accuracy and repeatability. They are widely used in petroleum, chemical, pharmaceutical, and food industries, particularly for measuring high-viscosity fluids.

WORKING PRINCIPLE

As the fluid passes through the meter, it causes the helical rotors to rotate axially. The rotation displaces a fixed volume of fluid, which is measured to calculate volumetric flow.

Basic equation:
Qv = n · Vc
Qv: volumetric flow rate (m³/s)
n: rotor rotation frequency (Hz)
Vc: displaced volume per rotation (m³).

Helical rotor flowmeters are less affected by fluid density and viscosity, providing stable and accurate performance.

STRUCTURAL FEATURES

• Body materials: stainless steel, cast iron, aluminum
• Measuring elements: helical (screw-type) rotors
• Output signals: magnetic pickup, pulse, digital signals
• Low pressure drop
• Excellent performance with high-viscosity fluids

ADVANTAGES AND LIMITATIONS

Advantages:

• High accuracy (±0.2% – ±0.5%)
• Reliable performance at low flow rates
• Suitable for viscous and dense fluids
• Minimal pressure loss

Limitations:

• Moving parts require maintenance
• Reduced lifespan with abrasive fluids
• Less suitable for fluids containing solid particles

APPLICATION AREAS

• Fuel and oil measurement
• Polymer and solvent monitoring in chemical industries
• Syrup, molasses, and honey measurement in food industry
• Precise dosing in pharmaceutical applications
• Lubrication systems in energy and automotive sectors

STANDARDS AND CALIBRATION

• OIML R 117: Standard for liquid measuring devices
• ISO/IEC 17025: Calibration laboratory accreditation
• ATEX-certified models for explosive environments
• Regular calibration is necessary to maintain accuracy

CONCLUSION

Helical rotor flowmeters play a vital role in industries requiring precise measurement of high-viscosity fluids. With their robust design, low pressure drop, and reliable accuracy, they provide long-term and dependable solutions for demanding industrial applications.