Valve

In process automation, control valves are the final elements responsible for executing the control signal. However, due to friction, fluid forces, actuator limitations, and other mechanical factors, the actual valve position often fails to match the input signal. A valve positioner—commonly referred to simply as a “positioner”—is the key device designed to eliminate this deviation. […]

1. Basic Principles: How Do Valves Cause Leakage? Valves operate by creating a seal between the valve plug (such as a valve disc, ball, or gate) and the valve seat, cutting off the fluid flow. Leakage typically occurs at two key locations: Seat Leakage: This happens when the valve plug and seat do not make

Explosion-proof junction box breather valves play a critical role in industrial environments, especially in areas where flammable or explosive gases are present. Below are the key functions of breather valves in explosion-proof junction boxes: 1. Maintaining Pressure Balance During operation, the internal pressure of an explosion-proof junction box may fluctuate due to temperature changes, heat

In chemical plants and automated control systems, selecting the correct drive voltage (220V single-phase vs. 380V three-phase) for electric valves directly impacts the stability of the equipment, energy consumption, and maintenance costs. This article explores how to determine the appropriate voltage based on key selection criteria and highlights the core advantages of each voltage level,

When operating a three-valve manifold for differential pressure instruments, two principles must always be observed: Never allow the condensate or sealing liquid in the impulse lines to drain. Never expose the measuring element (diaphragm or bellows) to sudden pressure or temperature stress. To achieve this, the three-valve manifold must be operated in the correct sequence

In tank farm piping design, both metal flexible hoses and emergency shut-off valves (ESVs) are critical safety components. However, when they appear on the same pipeline, engineers often ask: “Should the metal hose be installed upstream or downstream of the emergency shut-off valve?” This article explains the correct arrangement from the perspectives of functional requirements,

In process automation, the terms control valve, regulating valve, and instrument manifold (instrument valves) are mentioned daily.Although all of them are “valves,” they perform entirely different roles in a process control loop. This article provides a clear engineering-level comparison across system architecture, industry applications, sizing considerations, reliability, and safety. 1. A Simple Control Loop Perspective

In industrial fluid control systems, the velocity of the medium downstream of a control valve is a key factor affecting system stability, equipment service life, noise generation, and overall operating efficiency. Selecting an appropriate velocity range requires considering the fluid type, thermodynamic conditions, pipeline configuration, and valve design. There is no single universal value, but

The question of whether safety valves can forgo annual calibration depends on several factors, including regulatory requirements, equipment usage conditions, and risk management practices. Safety valves are critical components in ensuring the safe operation of pressure-containing equipment, and their reliability is paramount. Below is a detailed exploration of this issue. 1. Regulatory and Standards Compliance

Cryogenic valves are widely used in industries dealing with extremely low-temperature media such as liquid oxygen, liquefied natural gas (LNG), and others. These media are not only highly flammable and explosive, but they also vaporize rapidly upon warming, causing a volume expansion of several hundred times, which creates significant safety risks. So, why are high