How does the Q-type partial rotary valve electric device achieve fault tolerance?

In process industries such as petroleum, chemical industry, and electric power, valve electric devices are key actuators for controlling medium flow and pressure. If the valve loses control under high pressure, high temperature, or flammable and explosive conditions, it may cause catastrophic accidents such as medium leakage and explosion. Taking the leakage of ethylene pipeline as an example, the damage radius of its vapor cloud explosion (VCE) can reach hundreds of meters, and the direct economic loss can reach tens of millions of yuan. Therefore, the fault tolerance of valve electric devices has become a core indicator of industrial safety.

The Q-type partial rotary valve electric device (hereinafter referred to as Q-type electric device) achieves 10ms automatic switching when the main switch fails through the coordinated redundant design of mechanical limit and electrical feedback, successfully preventing many major accidents. This article will deeply analyze its technical principles and engineering practices, and reveal how it achieves the goal of "zero loss of control" through redundant architecture.

The fault tolerance of Q-type partial rotary valve electric device comes from its dual closed-loop control architecture, that is, the mechanical limit is used as the physical hard limit, and the electrical feedback is used as the dynamic adjustment layer. When the mechanical limit fails due to vibration or jamming, the electrical feedback system becomes the last line of defense.

The system consists of three parts: the main switch group, the backup switch group, and the emergency cut-off switch:

The main switch group: undertakes conventional opening and closing control, monitors the cam position through micro-contacts, and has an accuracy of ±0.5°;

The backup switch group: is independent of the electrical circuit of the main switch, adopts redundant logic design, and the response threshold is set in a staggered manner with the main switch;

The emergency cut-off switch: is directly connected to the safety instrument system (SIS) and forces power off when abnormalities such as overspeed and overload are detected.

When the main switch fails due to vibration or contact oxidation, the switching process of the backup switch group can be divided into three stages:

Fault detection: The backup switch group continuously monitors the contact status of the main switch and identifies contact resistance abnormalities through dynamic impedance analysis;

Logic judgment: The redundant controller completes fault diagnosis within 1ms and starts the backup switch group;

Fast switching: The contacts of the backup switch are closed with zero contact resistance through preloaded springs, and the signal transmission delay is less than 10ms.

Redundant architecture: engineering implementation of quadruple protection

The redundant design of Q-type electric equipment is not only reflected in the electrical level, but also runs through the multi-dimensional collaboration of mechanics, electronics, and software.

In terms of mechanical structure, the Q-type electric system adopts a dual-cam design. The main cam and the backup cam are driven by independent transmission shafts to ensure that a single point failure will not affect the other system. The travel switch also adopts a dual-contact structure. Even if a single contact fails, the other contact can still maintain signal transmission.

At the electrical level, the Q-type electric system is equipped with dual power supplies (main power supply + UPS backup power supply) and dual controllers (main controller + redundant controller). When the main controller fails, the redundant controller takes over control within 5ms through heartbeat signal detection to avoid signal interruption.

At the software level, the Q-type electric system adopts a dual-mode control algorithm:
Main mode: conventional control based on PID regulation;
Redundant mode: robust control based on fuzzy logic, automatically switching when the main mode fails.
In addition, the system has a built-in self-healing mechanism. When contact wear or poor contact is detected, the contact pressure is automatically adjusted or switched to the backup contact to extend the life of the equipment.