Pressure Control Device with Frequency Correction Circuit
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Solution Overview
Problem
Conventional pressure control devices struggle to maintain constant pressure within a chamber when the chamber volume is large relative to the gas flow or when the pipe between the pressure control device and the chamber is long, resulting in pressure fluctuations due to delay times.
Innovation Solution
A pressure control device equipped with a frequency characteristic correction circuit, which filters the pressure signal to raise the low-band frequency component, allowing for faster valve control and maintaining constant pressure by comparing the corrected signal with a set pressure signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If conventional pressure control is used with a large chamber volume or long pipe, then the system can handle large-scale applications, but pressure fluctuations occur due to delay time
Solution Approach 1:
The filter circuit performs preliminary correction on the pressure signal by amplifying low-frequency components before the comparison and valve control steps. This anticipatory signal processing compensates for the inherent delay in the control loop, allowing the system to respond more effectively to pressure changes despite the large chamber volume or long pipe length.
Solution Approach 2:
The invention changes the frequency characteristics of the pressure signal through the filter circuit, specifically boosting low-frequency components. This parameter transformation allows the control system to detect and respond to slow pressure changes more effectively, maintaining pressure stability in systems with large thermal/mass inertia caused by large chamber volumes or long pipes.
2Length of stationary object
If the pipe length between pressure control device and chamber is increased, then the system can accommodate larger distances, but the delay time increases causing pressure control instability
Solution Approach 1:
The invention replaces the mechanical/direct pressure transmission through long pipes with an electronic signal processing approach. The filter circuit electronically amplifies low-frequency pressure signal components, substituting the physical pressure wave transmission with an enhanced electrical signal that can be processed and acted upon more quickly, thereby reducing the effective delay time.
3Volume of stationary object
If the chamber volume is large relative to gas flow, then the system can accommodate large-scale processes, but pressure cannot be maintained constant due to control delay
Solution Approach 1:
The filter circuit performs preliminary enhancement of low-frequency pressure signal components before they reach the comparison circuit. This preliminary action ensures that even small pressure changes in large-volume chambers are amplified and detected early, allowing the valve control to respond more precisely and maintain pressure control accuracy despite the large chamber size.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively maintains constant pressure within the chamber by accelerating the valve opening time and correcting pressure signals based on the chamber volume and pipe length, preventing pressure fluctuations.
Implementation Method 1
The frequency characteristic of the filter circuit has a peak at a prescribed frequency, and corrects the pressure signal so as to raise a component of the prescribed frequency of the pressure signal
Data Source
AI summary
A pressure control device maintains a pressure within a target of pressure control at a set pressure. The pressure control device includes a correction circuit that corrects a pressure signal, which represents the pressure within the target of pressure control that is detected by a pressure sensor, such that the pressure signal approaches a set pressure signal representing the set pressure; a comparison circuit that compares the corrected pressure signal with the set pressure signal; and a valve drive circuit that controls an opening and closing of a flow control valve based on a comparison result from the comparison circuit. The correction circuit is a filter circuit. The frequency characteristic of the filter circuit has a peak at a prescribed frequency, and corrects the pressure signal so as to raise a component of the prescribed frequency of the pressure signal.