The Role of Gear-Type Flowmeter Technologies in the Chemical Industry and VSE Solutions

Summary
In the chemical and petrochemical industries, accurate flow measurement of polyurethane, epoxy, resin, paint, solvent-based coatings and heavy oils directly affects product quality, raw material consumption, reaction rate and process repeatability. High-viscosity fluids in particular (liquids with high resistance to flow) and non-Newtonian fluids (liquids whose viscosity changes according to flow conditions) can produce unstable results in standard flow measurement methods.

This study explains the importance of gear-type flowmeters (positive displacement flowmeters that count fluid in small fixed-volume packages) in the chemical industry; examines the role of gear-type flowmeter technologies in the chemical and petrochemical industries and VSE Volumentechnik solutions.

1. Introduction
In modern chemical industries, accurate flow measurement (measurement of the quantity of liquid passing per unit time), dosing accuracy and maintenance of mixing ratios are of critical importance. In polyurethane systems, the balance of polyol and isocyanate components; in epoxy resin applications, the resin-hardener ratio; and in paint production, the quantity of pigment and binder directly affect the final product quality [1].

The fundamental challenge encountered in these systems stems from rheology (the flow behavior of fluid). As viscosity (the resistance of fluid to flow) increases, flow becomes heavier, slower and more difficult to control. In non-Newtonian behavior, liquid can behave more fluidly or more thickly depending on mixing speed, pump pressure or shear effects. This can cause the flowmeter to exhibit different behavior in the same fluid at different process stages.

In turbine-type flowmeters (flowmeters that measure by the rotor being rotated by flow velocity), high viscosity can hamper the rotor's free rotation. In this case, the sensor detects not the actual flow rate but the rotor movement slowed by viscosity. In ultrasonic flowmeters (flowmeters based on sound wave propagation through flow), polymeric or high-viscosity liquids can attenuate the acoustic signal. In both cases, measurement is derived not from the volume passing directly but from the fluid velocity or signal behavior. Gear-type flowmeters operate on the positive displacement principle (counting by dividing fluid into defined volume segments). Two gears are positioned within the body with tight tolerances. Fluid fills small volume pockets created between the gear teeth and body; as the gears rotate, these volume pockets are transported from inlet to outlet. Thus liquid can be tracked not as continuous and indeterminate flow but as measurable volume increments [2,3].

Each gear tooth passage is converted to a pulse signal by magnetic or magnetoresistive sensors (electronic elements that detect gear movement without contact). As the number of pulses increases, the total volume passed; as pulse frequency increases, instantaneous flow rate is calculated. The K factor used in this calculation (the number of pulses generated per liter or unit volume) is the fundamental calibration information that introduces the flowmeter's volume measurement characteristic to the control system.

Another important parameter in calculations, interpolation (a method of digitally dividing a measurement step into smaller sub-steps), becomes even more important especially at low flow rates. When the sine-cosine signal obtained from a tooth passage is divided into smaller digital segments as indicated in Figure 2, the control system receives signals more frequently. This allows near-zero flow, short-duration doses and bidirectional flow changes to be tracked more clearly.

2. Application Areas in the Chemical Industry
The VSE product family does not consist of a single flowmeter model alone; it comprises mechanical measurement bodies, signal amplification units and digital communication layers. This structure enables the provision of the most suitable measurement solution according to the properties of the relevant fluid, process risks and automation requirements [4,5].

2.1 VSI Pre-Amplifier: Measurement Resolution at Low Flow
The VSI pre-amplifier is the signal processing layer that converts mechanical motion information from the flowmeter into high-resolution electronic signals. MR sensor technology is a sensor structure that precisely detects magnetic field changes and allows tracking of both flow velocity and flow direction through sine and cosine signals. The 1/4 tooth-pitch offset used in this structure, with the two sensors positioned 90 degrees out of phase, enables forward and reverse flow directions to be distinguished [6].

Through digital interpolation, each tooth passage is divided into smaller measurement steps and the flowmeter's resolution is increased. This characteristic provides an important advantage for micro-dosing—that is, controlled delivery of very small liquid volumes, tracking of near-zero flows, and more stable quality control in short-cycle production.

2.2 VS Series: High-Pressure and Viscous Resin Lines
The VS series is a heavy-duty gear flowmeter solution that stands out in processes requiring high pressure and mechanical durability. It can be used for measurement of polyurethane, epoxy resin, heavy mineral oil and similar clear but viscous liquids. Through its rigid body structure that maintains shape under pressure and precise gear tolerances that create repeatable volume pockets, it provides reliable and stable measurement performance [2].

2.3 VHM Series: Abrasive and Cleaning-Requiring Fluids
The VHM series is a gear flowmeter solution that stands out for measurement of paint, varnish, ink, solvent-based coatings and particle-containing fluids. In such applications, not only measurement accuracy but also the flowmeter's cleanability is of critical importance. When measurement areas and inner cavities where flow slows and residue can accumulate are excessive, resin or paint residues can dry; this can lead to cross-contamination of color, degradation of product quality and risk of mechanical locking. The VHM series is reliable against such risks.
VHM architecture is positioned as a solution that, through its optimized internal geometry, supports cleaning fluid to sweep the measurement chamber more effectively. For this reason, the VHM series can be evaluated not merely as a flowmeter but as process equipment that helps reduce maintenance time and preserve process continuity in lines with frequent product changes, color changes or solvent cleaning [2].

2.4 EF Ecoflow Series: Economic and Compact General Chemistry Solution
The EF Ecoflow series can be evaluated as an economical gear flowmeter option for general chemistry applications where heavy-bodied solutions in high-pressure classes are not required, low-pressure solvent transfer, simple spray coating systems and central lubrication lines. The fundamental value of this series is its ability to reduce costs arising from high technical specifications that are not needed, making gear-type measurement principle more accessible and applicable [3].

2.5 ATEX Standards and Safety Architecture in Explosive Areas
In chemical and petrochemical facilities, lines containing volatile fluids such as toluene, hexane, alcohol derivatives and light hydrocarbons can present explosive atmosphere risk. ATEX (European safety regulations for equipment to be used in explosive atmospheres) defines safety requirements for electrical and electronic equipment to be used in such areas. The availability of VSE flowmeter technologies with ATEX-certified options enables the measurement solution to be positioned not only in terms of performance but also in terms of field safety [1].

2.6 Industry 4.0, Digitalization and IO.flow® Integration
The IO.flow® module can be evaluated as a converter layer that connects the VSE flowmeter signal in the field to IO-Link-based digital automation infrastructure. IO-Link is an industrial communication structure that enables bidirectional data exchange between sensor and control system; it can transfer not only instantaneous measurement values but also device information, parameter settings and status data to the automation system.

This structure provides an important advantage for retrofit applications, digitalization efforts of existing systems without major mechanical modifications. Legacy-generation flowmeter infrastructure operating in the field can be made more traceable, parameterizable and data-capable through use of an appropriate electronic intermediate layer. Total operating time, total volume passed and device status data can be evaluated for predictive maintenance—an approach that estimates maintenance needs before failure occurs [1,7–9].

3. Conclusion
In the chemical and petrochemical industries, accurate flow measurement is regarded as a critical engineering element in terms of final product quality, process stability and production reliability. High viscosity, non-Newtonian flow behavior, abrasiveness and low-flow measurement requirements encountered in polyurethane, epoxy, resin, paint and solvent-based processes can limit the performance of conventional measurement methods based on velocity or acoustic signal interpretation. Gear-type flowmeters offer a powerful alternative in such demanding applications because they measure fluid in fixed and repeatable volume increments. The VSE product family offers an integrated solution structure that extends this measurement principle according to different process requirements.

The VS series stands out in heavy-duty and high-pressure applications, the VHM series in cleanability and abrasive fluid conditions, the EF Ecoflow series in economical general applications, the VSI pre-amplifier in measurements requiring high signal resolution, and the IO.flow® module in digital integration and predictive maintenance-focused automation infrastructure. These solutions examined in this study enable measurement equipment to be evaluated not merely as a technical component but as a strategic investment that supports process efficiency, product quality and operational continuity.

4. References
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[4] "Applications - Fluid Technology Group." [Online]. Available: https://www.e-holding.de/en/applications.html?company=vse. [Accessed: 16-Mar-2026].
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[7] "IO.Flow® Converter - VSE Volumentechnik GmbH." [Online]. Available: https://www.vse-flow.com/en/io-flow-r-converter.html. [Accessed: 15-Apr-2026].
[8] "Cal.Flow Calibration System - VSE Volumentechnik GmbH." [Online]. Available: https://www.vse-flow.com/en/cal-flow-calibration-system.html. [Accessed: 15-Apr-2026].
[9] "Electronic Evaluation Devices - VSE Volumentechnik GmbH." [Online]. Available: https://www.vse-flow.com/en/electronic-evaluation-devices.html. [Accessed: 15-Apr-2026].