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1. Introduction In the design and operation of chemical installations, the choice of instrumentation is not only related to production efficiency but also to intrinsic safety. In hazardous areas such as Zone 2, the explosion protection type of field instruments becomes a key decision. This article compares Intrinsically Safe (IS) and Explosion-Proof (Ex-d) instruments from […]

1. Definition of Surge A surge (also called a transient overvoltage/overcurrent) refers to a short-duration pulse that appears on power or signal lines. Time scale: From nanoseconds to milliseconds. Amplitude: Peak values often exceed more than twice the steady-state voltage/current. Waveform: Typical waveforms include 1.2/50 μs voltage waves and 8/20 μs current waves. Essentially, a

Introduction High-risk process units in the chemical industry refer to facilities that involve highly reactive chemical processes (e.g., nitration, sulfonation, halogenation, strong oxidation, diazotization, and hydrogenation) or operate under extreme conditions such as high temperature (≥300 ℃), high pressure (≥10 MPa), and cryogenic environments (≤−29 ℃).In addition, high-risk storage units are facilities for storing toxic

Introduction Relays are essential components in modern industrial automation and power systems. They act as switching and protection devices, enabling safe and efficient control of electrical circuits. Depending on the application—whether for signal amplification, overload protection, safety shutdown, or high-frequency switching—different types of relays are used. This article provides a structured overview of the most