Common Thermal Mass Flow Measurement Applications

Thermatel® TA2 thermal mass flow meters are up to the challenge of your most demanding applications.

TA2 thermal mass flow meters will help optimize your green energy initiatives by improving measurement of greenhouse gases and making processes less energy intensive and more energy efficient.


Activated sludge processes (and similarly an aerated basin) require air flow to allow the microorganisms to efficiently break down the waste materials. There needs to be enough air to the basin for the microorganisms to successfully consume the waste but not too much air where energy is wasted in running blowers. Flow meters are typically used to insure that the air flow is balanced to the various sections of the aeration basin. The amount of air needed can be optimized by the measurement of dissolved oxygen (DO) and the air flow can be measured by the TA2.

  • Low installation cost
  • Direct mass flow measurement
  • High reliability

The TA2 is also used for aeration flow measurement in froth flotation applications in the mining industry.



Digesters treat the remaining sludge; the process of microorganisms breaking down the materials in the absence of oxygen (anaerobic) gives off a mixture of methane and carbon dioxide. The digester gas can be used as an energy source (methane) or burned off, each requiring flow measurement. The facility can reduce greenhouse gas emissions or obtain carbon credits in the process. The TA2 has successfully been used in these applications involving moisture, low flow rates, and low pressures.

  • Excellent low flow sensitivity
  • High turndown
  • Both mass flow measurement and flow totalization
  • No moving parts
  • Retractable probe if cleaning required.


Landfill Gas (LFG)

Landfills produce a gas mixture composed primarily of methane and carbon dioxide. The EPA has specified the amount of carbon dioxide equivalent necessary for reporting greenhouse gas emissions and thousands of landfills fall under this rule. Landfills are also now incorporating programs to capture the LFG and use it as a fuel in electricity generation. It can also be monitored to obtain carbon credits. The gas can be moist and characterized by low flow rates.

  • Excellent low flow sensitivity
  • “Hot tap” assemblies available
  • Mixed gas calibrations

The TA2 is also used for biogas measurement.


Compressed Air Systems

A key role in energy and facilities management is making compressed air systems more reliable and efficient. The TA2 can be used to determine air usage at different parts of a plant or in leak detection. Valuable resources are wasted when a leak goes unnoticed or cannot be located. It is estimated that 30% of compressed air usage is due to leakage which can account for thousands of dollars of wasted air. The first step to reducing utility costs is to measure the usage.

  • Easy installation with use of an insertion probe with compression fitting
  • Accurate flow measurement under varying pressures
  • High turndown and good sensitivity at low flow rates


Flare Gas

Many flare applications exist that need to be monitored and measured. Flares can arise from burning exhaust gases or during upset conditions at a chemical plant or refinery. At wastewater treatment plants and landfills flares are used to burn the excess digester gas or LFG. Natural gas can also be burned in the gas field at the wellhead. All of these applications can require emissions reporting. As the composition of the gases will vary depending on application the method of calibration becomes critical.

  • High turndown with strong signal at low flows
  • Retractable probe assembly available
  • Calibration can be verified in the field


Combustion Air Flow

Combustion air flow to a furnace (boiler, etc.) is important to maintain a stoichiometric ratio with the amount of fuel being supplied. Too little air flow can result in incomplete combustion along with additional carbon monoxide or smoke depending on the fuel being burned. On the other hand too much air flow can cool the furnace and waste heat out of the stack. The repeatability of the air measurement is essential to obtaining the most efficient air to fuel ratio.

  • Repeatability of ±0.5% of reading
  • Direct mass flow measurement
  • Easy to install in an air duct


Natural Gas Measurement

Flow measurement of natural gas is important for energy management to improve combustion efficiency. Additionally, facilities that emit over 25,000 metric tons of carbon dioxide equivalent (CO2) per year must report these emissions to the U.S. Environmental Protection Agency (EPA). Formulas have been provided by the EPA for converting the natural gas usage into CO2. Monitoring the fuel to individual combustion sources can be a less expensive alternative than using a CEM system.

  • Strong signal at low flow rates with high turndown
  • Verify calibration in the field
  • Easy installation with low pressure drop
  • Direct mass flow measurement


Tank Blanketing

Tank blanketing is frequently used to maintain an inert environment in the vapor space of a tank. This is frequently found in tanks containing hazardous (explosive) chemicals for safety concerns. In addition, tank blanketing can be used to prevent oxygen from coming in contact with the product in the tank; this is often found with food products to prevent oxidation of the product. Nitrogen is typically used to provide the inert environment. While the addition of nitrogen is done by pressure in the tank, consideration should be given to monitoring the flow of nitrogen to identify leakage in the system.

  • Mass flow measurement
  • Easily installed in the pipe
  • Ability to measure very low flow rates


Thermal Flow Switch Applications

Pump Protection

Pump Protection: Installed on the discharge of a pump, a THERMATEL switch provides rapid indication of a low flow or no flow condition to prevent pump damage. No moving parts, excellent low flow sensitivity, and low hysteresis between alarm and reset points are all important features in this application. Enhanced temperature compensation minimizes set point drift due to varying process temperatures.


Cooling Water / Cooling Air

Maintaining the flow of cooling air or water is essential to protect heat generating equipment. A reliable flow switch will ensure that sufficient cooling media is flowing in the pipe. A low flow alarm will provide indication of inadequate cooling prior to overheating of the device being protected.



A THERMATEL switch can be calibrated to detect the difference between two media based upon the difference in thermal conductivity. This can include wet/dry, oil/water interface, air/foam and foam/liquid. The sensitivity of the switch can easily be adjusted for a wide range of conditions. Probes can be mounted from the top or side of the tank.


Chemical Feed Pumps

Monitoring the addition of chemicals into a process is vital for good performance. The TD1/TD2 with the low flow body can handle extremely low flow rates of both liquids and gases. With the TD2, time delay can be added.

Chemical Feed Pumps

Relief Valve Monitoring

When installed downstream of a relief valve, the switch can detect when flow occurs. The low flow sensitivity of the sensor permits the switches to be calibrated to detect minor valve leakage.


Lubrication Systems

The flow switch with the low flow body can be used to ensure that sufficient quantities of lubrication oil are flowing throughout the entire lubrication system. No moving parts and large openings prevent buildup or plugging which can occur with mechanical switches.

Other Applications:

• Exhaust Flow Monitoring• Seal Leakage         
• Safety Showers/Eyewash Stations• Leak Detection
• Vacuum Pumps Seal Fluid• Paint Flow
• Sampling Systems

• Analyzer Flow