Pressure Control Device with Signal Subtraction for Chamber Stabilization
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Solution Overview
Problem
Conventional pressure control devices face challenges in maintaining constant pressure within a chamber, especially when the chamber volume is large or the pipe length between the pressure control device and the chamber is significant, leading to delayed pressure stabilization and repetitive pressure fluctuations.
Innovation Solution
A pressure control device with a controller that adjusts the gas flow rate by subtracting or adding a signal related to the gas supply or outflow from the set pressure signal, allowing for precise control of the flow rate control valve to maintain constant pressure within the chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If conventional pressure control is used with a large chamber volume or long pipe length, then the system structure is simple, but pressure stabilization is delayed and pressure fluctuations occur repetitively
Solution Approach 1:
The controller performs preliminary action by subtracting a predetermined value from the set pressure signal before comparison with the detected pressure signal. This anticipates the pressure delay caused by large chamber volume or long pipe length, allowing the system to compensate in advance and achieve faster pressure stabilization without repetitive fluctuations.
Solution Approach 2:
The controller applies preliminary anti-action by preemptively adjusting the set pressure signal downward (subtraction) to counteract the expected pressure delay and potential overshot. This prevents the repetitive pressure fluctuations that would otherwise occur due to the time lag between valve actuation and actual pressure change in the chamber.
2Manufacturing precision
If the chamber volume is large or pipe length is long, then the system can handle larger gas flows, but the pressure control responsiveness decreases
Solution Approach 1:
The controller changes the parameter of the set pressure signal by subtracting a predetermined value to account for the delayed pressure response. This parameter adjustment compensates for the sluggish responsiveness caused by large chamber volume or long pipe length, enabling accurate pressure control without sacrificing responsiveness.
Solution Approach 2:
The controller uses feedback from the detected pressure signal combined with the predetermined subtraction value to continuously adjust the flow rate control valve. This feedback mechanism with preemptive adjustment maintains high pressure control accuracy and responsiveness even with large chamber volumes or long pipe lengths.
3Stability of the object's composition
If the flow rate control valve is switched on/off rapidly to maintain pressure, then pressure stability improves, but pressure oscillations increase
Solution Approach 1:
By subtracting a predetermined value from the set pressure signal in advance, the controller prevents pressure overshot and subsequent oscillations. This preliminary anti-action allows for smoother valve modulation rather than rapid on/off switching, maintaining pressure stability while eliminating harmful pressure oscillations.
Solution Approach 2:
The predetermined subtraction value acts as a cushioning factor that prevents excessive pressure rise. This beforehand cushioning allows the system to maintain pressure stability through gentler control adjustments rather than aggressive valve switching, thereby reducing pressure oscillations.
Data Source
AI summary
A pressure control device controls a flow rate of gas supplied to a pressure control target to maintain an inside of the pressure control target at set pressure. The pressure control device includes a controller that is configured to: subtract, at a predetermined ratio, a signal related to the supply of gas from a set pressure signal indicating the set pressure, when gas is being supplied into the pressure control target in order to bring the inside of the pressure control target to the set pressure; compare a detected pressure signal indicating pressure within the pressure control target with the set pressure signal subjected to the subtraction; and control, on the basis of a comparison result obtained by the controller, a flow rate control valve which controls a flow rate of gas supplied to the pressure control target.