The detection components of differential pressure flowmeters can be classified into the following major categories according to their working principles

       A differential pressure flowmeter is based on the throttling principle of fluid flow and measures flow by utilizing the pressure difference generated when fluid passes through a throttling device. It is currently one of the mature and commonly used methods for flow measurement in production. It typically consists of a throttling device that converts the measured flow into a differential pressure signal, a differential pressure gauge that converts this differential pressure into a corresponding flow value for display, and a display instrument. In modular instruments, the differential pressure signal generated by the throttling device is often converted by a differential pressure transmitter into a corresponding standard signal (electrical or pneumatic) for display, recording, or control purposes.

　　Application composition:

　　A differential pressure flow meter consists of a primary device (the sensing element) and a secondary device (the differential pressure transmitter and flow display instrument). Differential pressure flow meters are typically classified by the type of sensing element, such as orifice plate flow meters, Venturi flow meters, averaging pitot tube flow meters, and pitot tube principle-based flow meters such as the Verabar flow meter.　

　　Secondary devices include various mechanical, electronic, and electromechanical integrated differential pressure gauges, differential pressure transmitters, and flow display instruments. They have developed into a major category of instruments with a high degree of three-fold standardization (serialization, generalization, and standardization) and a wide variety of types and specifications. They can measure not only flow parameters but also other parameters (such as pressure, level, density, etc.).

　　According to their operating principles, the sensing elements of differential pressure flowmeters can be classified into several major categories: throttling devices, hydraulic resistance type, centrifugal type, dynamic pressure head type, dynamic pressure head gain type, and jet type.

　　Test pieces can also be divided into two major categories according to their degree of standardization: standard and non-standard.

　　A standard test piece is one that, as long as it is designed, manufactured, installed, and used in accordance with standard documents, allows its flow rate value to be determined and its measurement error to be estimated without the need for actual flow calibration.

　　Non-standard test pieces are less mature and have not yet been included in international standards.