Belimo ultrasonic flow sensor

Belimo Releases New Ultrasonic Flow Sensors with Glycol Compensation

August 29, 2019

Belimo ultrasonic flow sensorBelimo releases new larger sizes inline flow sensors, 2½” to 6″ that offer automatic glycol measurement and compensation for optimal system performance. Trusted flow measurement is essential in maximizing HVAC system efficiency and ensuring occupant comfort. Belimo flow sensors utilize ultrasonic technology with glycol compensation to provide accurate and repeatable flow measurements of water and water/glycol mixtures without drift in any HVAC application.

Figure 1

The Belimo flow sensors use two offset transducers (refer to Figure 1) to determine the flow velocity by measuring the speed of sound in the heat transfer fluid. The downstream transit time is measured by passing an ultrasonic pulse from the lower transducer to the upper transducer; the process is then reversed to obtain the upstream time. Transit times differ based on the flow through the sensor tube; the downstream pulse is accelerated, the upstream pulse is impeded and slowed. The ultrasound pulses with the fluid temperature can be used to calculate the kinematic velocity (vmeas) and determine the measured volumetric flow.

The flow sensors have a patented automatic glycol compensation algorithm that selects the correct fluid properties for the flow and energy calculation eliminating manual input of glycol percentage for sensor setup. The algorithm can be applied to a range of heat transfer fluids, ensuring accurate and repeatable measurements. The automatic glycol concentration minimizes drift and provides trusted flow measurement by continuously compensating glycol concentration in a hydronic system. The Belimo inline flow sensors are an advancement in thermal energy with ultrasonic transit-time technology that automatically measures and compensates glycol concentration. ‘Fit and forget’ sensors to compensate variable and changing viscosities. The sensors have a rugged design with no moving parts, require no calibration, and provide accurate, repeatable measurements improving the control and efficiency of HVAC systems. All flow sensors are wet calibrated to simulate field operation and available with NIST traceable calibration certification. The 2½” to 6″ flow sensors now completes the FM series flow sensor offering. The new sizes will be available in August.

About Belimo

Belimo is the global market leader in the development, production, and marketing of field device solutions for controlling heating, ventilation, and air conditioning systems. Actuators, control valves, and sensors make up the company’s core business. Known for its direct-coupled actuator and innovations in pressure independent control valve technology, Belimo has solutions to maintain an efficient building environment. For 40 years, Belimo has provided innovations in comfort, energy efficiency, and safety solutions to customers through the world, all of which are backed by Belimo’s unsurpassed five-year warranty.

For more information, contact Belimo at 1-800-543-9038 or visit the website at