Valve

When there is a significant deviation between the actual valve position and the DCS (Distributed Control System) display (i.e., the actual valve opening differs considerably from the DCS screen reading), process control can be affected. To resolve this, a systematic approach must be taken to investigate signal transmission, positioner calibration, actuator functionality, and DCS settings. […]

When using a differential pressure flowmeter to measure steam, where exactly should the shut-off valve on the pressure tap be installed — before or after the condensation tank? According to some literature, it should be installed after the condensation tank. However, in practice, most installations place it before the tank. Which of these is correct?

This seemingly simple question has caused confusion for many companies and designers. Some choose to install cut-off valves, while others don’t, with practices varying widely. But what do the standards say? Are there clear requirements in the regulations? In this article, we will clarify the principles for the installation of cut-off valves in safety valve

A Common Engineering Misunderstanding in Atmospheric and Low-Pressure Storage Tanks In the petroleum, chemical, energy, and pharmaceutical industries, atmospheric and low-pressure storage tanks are among the most widely used process equipment.Unlike pressure vessels, the safety of these tanks does not rely on shell strength, but instead depends heavily on the effectiveness of their venting systems.

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,