Flow Measurement Instruments

Accurate, Reliable Flow Measurement for Industrial Applications

Flow measurement instruments are essential for monitoring and controlling liquids and gases across industrial processes. From low-flow chemical injection to large duct and condenser monitoring, accurate flow measurement improves efficiency, safety, and process reliability.

Bionetics CESG provides a comprehensive range of Rheotherm thermal flow meters, flow switches, and multi-sensor instruments engineered for long-term accuracy, minimal maintenance, and dependable operation in demanding environments.

Thermal Flow Measurement Technology

Rheotherm instruments use thermal mass flow measurement technology to directly measure mass flow independent of pressure and temperature changes. With no moving parts, these instruments deliver stable, repeatable measurements with low pressure drop and minimal maintenance.

Rheotherm and RheoVac instruments are available with integral or remote electronics and support a wide range of industrial output signals and communication protocols.

Available Outputs and Interfaces

• Analog: 4–20 mA, 0–5 VDC, 0–10 VDC
• Digital: Serial, Modbus, HART
• Standard or custom process connections

Thousands of installations across multiple industries validate their long-term reliability and low life-cycle cost.

Key Benefits of Rheotherm Flow Measurement Instruments

• No Moving Parts – Eliminates mechanical wear and reduces maintenance
• Highly Repeatable Measurements – Ideal for control and monitoring applications
• Wide Turndown Ratio – Accurate measurement from very low to high flow rates
• Chemical & Temperature Resistance – Performs in harsh process environments
• Low Maintenance Operation – Reduced downtime and operating costs
• ISO 9001:2015 Certified – Manufactured under strict quality standards

Flow Measurement Products

Low Flow Liquid Meters
Rheotherm thermal mass low flow liquid meters are designed to measure extremely low liquid flow rates—from several gallons per minute down to 10 cc/day. These meters are well suited for chemical dosing, injection, and process control applications.

Applications include:

• Chemical injection and metering
• Corrosive and aggressive liquids
• Low- and high-viscosity homogeneous liquids

Compatible Materials
Stainless steel, Hastelloy, Monel, Titanium, Tantalum, Inconel, and Quartz.

These meters feature an unobstructed flow path and are rated for high temperature, high pressure, and hazardous environments. Learn more about Low Flow Liquid Meters

Low Flow Gas Meters
Rheotherm TU and TUL thermal mass gas meters provide accurate measurement of low gas flow rates, even in applications involving corrosive, dirty, or explosive gases.

Typical gases measured:

• Methane and natural gas
• Air and carbon dioxide
• Ammonia and sulfur dioxide
• Butane, ethanol, and specialty gases

Electropolished sensor options are available for ultra-high-purity gas applications. These meters are commonly installed in small lines (1″ and under) and support flow ranges from 25 SCFM to several hundred SCFM.

Optional backlit LCD displays provide real-time access to flow rate and temperature data. Explore Low Flow Gas Meter Solutions

Duct Flow Meters, Air & Gas
Rheotherm thermal mass insertion probes provide accurate air and gas flow measurement in pipes and ducts ranging from 1 inch to several feet in diameter.

Key applications:

• Stack gas monitoring
• Digester gas measurement
• Vent air and exhaust monitoring

Manufactured from stainless steel, titanium, or Hastelloy, these meters offer maintenance-free operation and compatibility with corrosive and explosive gases. The Rheovec™ flow conditioner improves accuracy in installations with limited straight-run piping. View Duct and Stack Flow Meters

Low Flow Controller
The Rheotherm Model 210 Low Flow Controller measures and controls extremely low gas or liquid flow rates with high precision.

• User-adjustable flow setpoints
• Local or remote configuration
• Analog flow output for process control

This solution combines measurement and control into a single, compact instrument. See Low Flow Controllers

Thermal Mass Flow Switches    
Rheotherm thermal flow switches provide reliable high- or low-flow indication for liquid and gas service.

Unlike flow meters, flow switches activate a relay output when a user-defined flow threshold is reached. Adjustable setpoints allow for flexible control and alarm functionality.

Flow switches are often used as a cost-effective alternative where continuous measurement is not required. Browse Flow Switch Options    

RheoVac Multisensor Flow Monitors 
The RheoVac family combines flow, pressure, temperature, and humidity measurement into a single advanced instrument.

Using an integrated calculation engine, RheoVac instruments separate air and water components to deliver outputs such as:

• Air mass flow rate
• Water mass flow rate
• Humidity and dew point
• Partial pressure

These instruments are widely used for:

• Power plant condenser performance monitoring
• Industrial drying and evaporation processes
• Vacuum pump capacity monitoring

Outputs are delivered via analog, Modbus, or OPC protocols for seamless system integration. Learn More about RheoVac Multisensor Instruments 

Custom Process Measurements   
With over 50 years of experience, Bionetics CESG specializes in solving complex flow measurement challenges that standard instruments cannot address.

Our engineering team designs custom flow measurement and control solutions for demanding applications, including:

• Specialized chemical processes
• Extreme temperature and pressure environments
• Aerospace, offshore, and research applications

If your application or process is not listed here, our team can work with you to develop a tailored solution.

Contact us to discuss your flow measurement requirements