Insertion type thermal gas mass flow meter

The insertion type thermal Gas Mass Flowmeter is a Mass Flowmeter, just adopting an insertion structure to install conveniently , and the gas mass flowmeter ,also known as an inertial flowmeter, is a device that measures the mass flow rate of a fluid traveling through a tube. The mass flow rate is the mass of fluid traveling past a fixed point per unit of time.

The mass Flow Meter does not measure the volume per unit time (e.g. cubic meters per second) passing through the device; it measures the mass per unit time (e.g. kilograms per second) flowing through the device. Volumetric flow rate is the mass flow rate divided by fluid density. If the density is constant, then the relationship is simple. If the fluid has varying density, then the relationship is not simple. For example, the fluid density may change with temperature, pressure, or composition. The fluid may also be a combination of phases such as a fluid with entrained bubbles. Actual density can be determined due to the dependence of sound velocity on the controlled liquid concentration.

The thermal gas mass flowmeter is designed based on the principle of thermal diffusion.

The meter uses the constant temperature difference method to accurately measure gas. It has the advantages of small size, high digitization, easy installation and accurate measurement.

The sensor part is composed of two reference level platinum resistance temperature sensors. When the instrument is working, one sensor can continuously measure the medium temperature T1; the other sensor’s temperature rises to higher than the medium temperature T2 through self-heating, it is used to sense the flow rate of the fluid,  so it’s known as velocity sensor. The temperature △ T =T2-T1, T2˃T1, when there is a fluid flowing, gas molecules collide with the sensor and take away the heat of T2, which makes the temperature of T2 reduction. If to keep △ T unchanged, it is necessary to increase the supply current of T2. The faster the gas flows, the more heat will be taken away.

There is a fixed functional relationship between gas flow velocity and incremental heat, which is the principle of constant temperature difference.