Thermal Gas Mass Flow Meter for Process Control Systems

Thermal Gas Mass Flow Meter for Process Control Systems

FLR Series Thermal Gas Mass Flowmeter

Description

A thermal gas mass flow meter is designed based on the principle of thermal diffusion and uses the constant temperature difference method to accurately measure gases. It features a compact size, high digitization, easy installation, and precise measurement.

The sensor section consists of two reference-grade platinum resistance temperature sensors. During operation, one sensor continuously measures the medium temperature T1; the other is self-heated to a temperature T2 higher than the medium temperature and is used to detect the fluid flow velocity, known as the velocity sensor.

The temperature difference is ΔT = T2 – T1, where T2 > T1. When fluid flows through, gas molecules collide with the sensor and carry away heat from T2, causing its temperature to drop. To maintain a constant ΔT, the supply current to T2 must be increased. The faster the gas flows, the more heat is carried away. There is a fixed functional relationship between the gas flow rate and the increased heat, which is the basis of the constant temperature difference principle.

Advantages

• It is a true mass flow meter that requires no temperature or pressure compensation for gas flow measurement, ensuring simple and accurate operation. It can provide gas mass flow or standard volumetric flow.

• It features a wide turndown ratio and can measure gas velocities from as high as 100 Nm/s to as low as 0.1 Nm/s, making it suitable for gas leak detection.

• It has excellent vibration resistance and a long service life. The sensor contains no moving parts or pressure-sensitive components, ensuring measurement accuracy is unaffected by vibrations.

• It is easy to install and maintain. Under appropriate field conditions, installation and maintenance can be performed without shutting down production (special customization required).

• It adopts a fully digital design, providing accurate measurement and easy maintenance.

• With RS-485 or HART communication, it supports factory automation and system integration.

Techanical Specification

Flow Range

Shanghai Cowell Machinery Co., Ltd.