Overview

The pFlow QMF Inline Micro Flow Sensor is a high-precision instrument engineered for accurate and repeatable measurement of low-viscosity fluids in small-diameter piping. Designed for demanding industrial environments, the QMF series provides a robust and reliable solution for monitoring and controlling micro-flow applications where precision is paramount. Its compact inline design allows for easy integration into existing systems, minimizing installation complexity and footprint. This sensor is the ideal choice for system integrators, engineers, and facility managers in sectors such as high-performance computing, advanced agriculture, and chemical processing who require dependable flow data to optimize their processes, ensure product quality, and maintain operational efficiency. The QMF sensor’s ability to deliver precise measurements at flow rates as low as 0.1 L/min makes it an essential component for resource management and process automation in mission-critical systems.

Measurement Principle

The pFlow QMF Inline Micro Flow Sensor operates on a proven turbine-based measurement principle, which is optimized for high-accuracy readings in low-flow conditions. As fluid passes through the sensor’s DN10 body, it impinges upon a miniature, low-inertia turbine rotor, causing it to rotate at a speed directly proportional to the fluid velocity. This rotor is meticulously balanced and mounted on low-friction bearings to ensure an immediate and linear response to changes in flow rate, even at the lowest end of its operational range. An integrated Hall-effect sensor detects the rotation of the turbine blades, generating a high-resolution train of electrical pulses. Each pulse corresponds to a discrete volume of fluid. The onboard microprocessor then processes this pulse signal, converting it into a calibrated flow rate and totalized volume. This method provides exceptional linearity and repeatability across the sensor’s entire measurement range, from 0.1 to 35 L/min, ensuring that the data output is consistently accurate and reliable for process control and monitoring.

Engineering Design

The pFlow QMF sensor is engineered for durability and long-term performance in industrial settings. The sensor body is constructed from high-grade, chemically resistant materials, ensuring compatibility with a wide range of fluids, including deionized water, glycols, and mild chemical solutions. Its robust inline construction, with a nominal diameter of DN10, is designed to withstand the mechanical stresses of industrial piping systems. The internal wetted components, including the turbine and bearings, are selected for their low friction and high wear resistance, which contributes to the sensor’s extended service life and stable performance over time. The sensor’s electronics are housed in a sealed, IP-rated enclosure, protecting them from dust, moisture, and other environmental contaminants. This thoughtful design minimizes maintenance requirements and ensures reliable operation. The integration of both RS485 Modbus and 4-20mA/OCT outputs provides versatile connectivity options, allowing for seamless integration with a variety of industrial control systems, PLCs, and data acquisition hardware. This dual-output capability simplifies system architecture and reduces the need for additional signal converters, making it a cost-effective and flexible solution for modern industrial automation.

Key Features

• High-Precision Measurement: Delivers an accuracy of ±2% of full scale (FS) for reliable and repeatable flow monitoring in critical processes.
• Wide Measurement Range: Accurately measures flow rates from 0.1 to 35 L/min, making it suitable for a broad spectrum of micro-flow applications.
• Compact Inline Design: The DN10 body allows for straightforward installation in space-constrained environments without complex piping modifications.
• Robust Construction: Built with chemically resistant materials to ensure compatibility with various low-viscosity fluids and long-term operational durability.
• Dual Output Signal: Provides both RS485 Modbus and 4-20mA/OCT outputs for flexible integration with standard industrial control and data acquisition systems.
• Low-Inertia Turbine: A precision-engineered turbine ensures a rapid and linear response to changes in flow, enhancing measurement accuracy at low velocities.
• Integrated Electronics: Onboard microprocessor handles signal processing and conversion, providing a clean, calibrated output and simplifying system design.

Industrial Applications

The pFlow QMF Inline Micro Flow Sensor is engineered for a variety of industrial applications where precise flow measurement is critical for operational success. Its robust design and high accuracy make it an indispensable tool in several key sectors:

• Data Center Liquid Cooling: In high-density data centers, the QMF sensor is used to monitor and control the flow of liquid coolants to server racks and other critical IT infrastructure. Precise flow management ensures optimal thermal performance, prevents overheating, and reduces energy consumption by enabling dynamic cooling adjustments based on real-time load.
• Agricultural Drones and Precision Farming: The sensor is integrated into agricultural drones and automated irrigation systems to precisely measure the application of fertilizers, pesticides, and water. This enables farmers to implement precision agriculture techniques, optimizing crop yields, reducing waste, and minimizing environmental impact.
• Chemical Dosing and Blending: In chemical processing and manufacturing, the QMF sensor provides accurate measurement for dosing and blending systems. Its chemical resistance and high precision ensure that exact quantities of additives, catalysts, or reagents are dispensed, leading to consistent product quality and optimized use of raw materials.
• Laboratory and Research: The sensor is utilized in scientific research and laboratory settings for experiments that require precise fluid handling and measurement. Its compact size and accuracy are ideal for pilot plants, test benches, and analytical instrumentation.
• Water Treatment and Purification: In water purification systems, such as reverse osmosis and deionization, the QMF sensor monitors the flow of water through various stages of treatment. This ensures the system operates efficiently and that the final product meets required purity standards.

Technical Specifications

Frequently Asked Questions (FAQ)

What types of fluids are compatible with the pFlow QMF sensor?

The pFlow QMF Inline Micro Flow Sensor is designed for use with a variety of low-viscosity fluids. Its wetted parts are made from chemically resistant materials, making it suitable for deionized water, glycols, and a range of mild chemical solutions. We recommend consulting the datasheet or contacting our engineering team to confirm compatibility with specific fluids.

How does the dual-output feature benefit my application?

The dual-output capability, offering both RS485 Modbus and 4-20mA/OCT signals, provides significant flexibility for system integration. You can connect the sensor to modern digital control systems using Modbus for advanced diagnostics and data logging, while simultaneously using the analog 4-20mA signal for simple integration with legacy PLCs or local displays. This eliminates the need for external signal converters, reducing system complexity and cost.

Can the QMF sensor be installed in any orientation?

For optimal performance and to ensure the longevity of the turbine bearings, it is recommended to install the pFlow QMF sensor in a horizontal position with the flow direction arrow aligned with the fluid path. Installation in vertical lines is possible, but it is best to ensure the flow is directed upwards to keep the pipe full and prevent air pockets from affecting measurement accuracy.

What is the maintenance schedule for this micro flow sensor?

The pFlow QMF sensor is engineered for minimal maintenance. However, the frequency of inspection and cleaning will depend on the cleanliness of the fluid being measured. It is good practice to install a filter upstream of the sensor to prevent particulate matter from damaging the turbine. Periodic checks for any signs of wear or buildup are recommended, especially in applications with aggressive or contaminated fluids.

How does the sensor perform at the very low end of its measurement range?

The sensor is specifically designed for high performance in micro-flow applications. The low-inertia turbine and high-sensitivity Hall-effect sensor ensure a linear and repeatable response even at flow rates as low as 0.1 L/min. This makes the pFlow QMF an excellent choice for applications requiring precise control and monitoring of very small fluid volumes.

Request a Quote

Contact Seven Star LLC to request a quote (RFQ) or download the official pFlow QMF datasheet. Our engineering team is ready to assist with your flow measurement requirements.