Clean Room Pressure Control with Adaptive Dead Zone Tuning
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Solution Overview
Problem
Existing room pressure control systems in clean rooms face challenges in maintaining constant pressure while reducing the operational load on pressure control valves, leading to reduced valve lifetime and compromised responsiveness to pressure fluctuations.
Innovation Solution
A room pressure control system that dynamically adjusts dead zone parameters based on pressure stability, using an air supply valve and an exhaust valve to maintain set pressure differences, with processing circuitry determining fluctuation and stability to optimize valve operations for either responsiveness or reduced operations depending on conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If a dead zone control function is implemented to reduce valve operations, then valve lifetime is extended, but responsiveness to pressure fluctuations is reduced
Solution Approach 1:
The dead zone width is made dynamically adjustable based on pressure stability assessment. When pressure fluctuations are detected, the dead zone width is reduced or eliminated, allowing rapid valve response. When pressure is stable, the dead zone width is increased to reduce unnecessary operations and extend valve lifetime.
Solution Approach 2:
The control parameters (dead zone width) are changed based on the assessed stability of room pressure. The system transitions between different parameter sets: a first parameter set with larger dead zone for stable conditions, and a second parameter set with smaller or zero dead zone for unstable conditions, optimizing both valve lifetime and responsiveness.
2Productivity
If a fixed dead zone parameter is used to reduce valve operations, then the number of operations is reduced, but controllability of room pressure is degraded
Solution Approach 1:
The dead zone parameter transitions from a fixed value to a dynamically adjustable parameter. The system continuously monitors pressure stability and adjusts the dead zone width accordingly, enabling the parameter to adapt to changing operational conditions and maintain optimal controllability.
Solution Approach 2:
The system implements feedback control by monitoring room pressure stability and using this information to adjust the dead zone parameter. When pressure deviations are detected, the feedback mechanism reduces the dead zone or eliminates it, ensuring timely corrective actions are taken to maintain pressure controllability.
Data Source
AI summary
A room pressure control system includes an air supply valve, an exhaust valve, and controller circuits. One of the controller circuits includes a room pressure correction control circuit that controls the valve operating as a room pressure control valve, between the air supply valve and the exhaust valve, so that the room pressure coincides with a set room pressure value; and processing circuitry that determines whether the room pressure easily fluctuates, determines whether the room pressure is stable, and sets parameters. In particular, the processing circuitry sets a dead zone parameter with which responsiveness of room pressure control is valued when it is determined that the room pressure easily fluctuates and otherwise sets a dead zone parameter with which reduction in the number of operations of the room pressure control valve is valued above the responsiveness of the room pressure control.