【2025 Instrument Valve Groups】Instrument valve groups (Group 1, Group 2, Group 3, Group 4, Group 5)
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This post was last edited by The one on 2025-11-10 06:42. Valve assemblies are key components that connect industrial automation instruments such as pressure transmitters and differential pressure transmitters to the process pipelines; they are used primarily for isolating, balancing, draining, or calibrating these instruments. Proper installation and operation of these valve assemblies have a direct impact on the accuracy of measurements and the safety of the equipment. I. Structure and purpose of a valve assembly (indicator valve): It usually consists of a single globe valve (such as a needle valve), which is used to control the flow of fluid to and from a single instrument (such as a pressure gauge or pressure transmitter), serving to provide isolation and protection.
II. Two-valve assembly: Structure and purpose: It consists of two stop valves (such as a valve on the high-pressure side and one on the low-pressure side), and is commonly used in situations where it is necessary to control the media on the high-pressure and low-pressure sides separately (such as for simple differential pressure measurement). It does not have a balance valve, and is suitable for low-pressure applications where high precision is not required.
III. Three-valve assembly: Structure and purpose – This is the most commonly used valve assembly, consisting of a \"high-pressure stop valve (HP)\\", a \"low-pressure stop valve (LP)\\", and a \"balance valve (BV)\“. It is primarily used for starting up, shutting down, and calibrating differential pressure transmitters; the balance valve helps to eliminate the pressure difference between the high-pressure and low-pressure sides, thereby protecting the instrument’s diaphragm from damage caused by excessive pressure in one direction.
IV. Four-valve assembly: Structure and purpose – A \"drain valve (DV)\\" is added to the three-valve assembly; it is used in situations where it is necessary to regularly drain the medium (such as accumulated liquid or impurities), especially in cases involving high-viscosity or particulate-containing media. The drain valve is usually connected to the low-pressure side or the common terminal.
V. Five-valve assembly: Structure and purpose: Two additional discharge valves are added to the three-valve assembly (the “High-pressure side discharge valve (DV-HP)” and the “Low-pressure side discharge valve (DV-LP)”), which are used for high-precision measurements or in situations where it is necessary to discharge the fluids from the high-pressure and low-pressure sides separately (for example, with corrosive or toxic fluids, to prevent cross-contamination).