are flow measurement instruments used to measure the mass flow rate of air and gases directly. The flow meter is available in high temperature and pressure designs usually built by special materials including PFA, ceramic .They use the thermal properties of the fluid to measure the flow of a fluid in a duct or pipe. Thus, thermal flow meters are mainly used in the gas and air measurement applications.
What is the thermal mass flow meter?
A thermal flow meter is also known as a thermal dispersion flow sensor
is an instrument used for measurement of the total mass flow rate of gases and fluids flowing through conduits that are closed. The meters comprise of a probe and gas flow transmitter used with temperature sensors situated at the bottom of the probe in the pins. They operate either by maintaining the temperature probe constant and measuring the temperature required to do so or by measuring an associated temperature change by introducing a known amount of heat into the flow stream.
Where to use a thermal flow meter
Thermal flowmeters are widely used in measuring the mass flow of industrial gases and clean gases such as nitrogen, air, hydrogen, argon, ammonia, and helium. They can also be used and applied in measuring pure gases which are used in semiconductor production and laboratory experiments. They are also used in petrochemical and chemical plants when the thermal properties of the gases are identified. The flow of corrosive gases such as hydrogen sulfide and hydrogen chloride can be measured with proper attention to the materials of construction.
Mass flow meters can also be used in measuring combustion air in large boilers, sampling air in nuclear plants, gas chromatography, filter testing and in the development and research applications. Thermal flowmeters are suited in measuring the high rangeability of very low flows and measuring large flows such as natural gases and compressed air.
Advantage of thermal flow meters
One of the advantages of thermal flow meters is that it works independently of density, pressure and viscosity. It also offers high accuracy and has a very low drop in pressure. Thermal flowmeters also have a large span and also do not require temperature and pressure compensation. It also has a short response time, rugged in construction and can be easily sterilized. Used for measurement of direct gas flow and can be used in the food, paper, mining, textile and pharmaceutical industries.
Why we use a thermal flow meter to measure gas
Therma mass gasl flowmeters are used because of their robust and compact design that provides excellent repeatability of continuous measurement of mass flow. It is used in various applications and different industries since it’s extremely versatile. It is also used in measuring high flow rates of gasses where the technical efforts of a by-pass measurement with a laminar flow element and a capillary sensor are exceeded. It is also preferred in applications such as aeration processes, burner control, environmental air sampling and leak rate tests at atmospheric conditions. They are also used since they enlarge the scope of measurement solutions for low-pressure requirements, high flow rates, and creating suitable conditions in a local working environment.