Vaporizer Valve Integral Gain Switching for Faster Settling
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Solution Overview
Problem
Existing vaporization devices face issues with prolonged settling times and instability in fluid control due to temperature-related thermal contraction and expansion of control valves, leading to offset and overshoot, which cannot be effectively addressed by increasing integral gain without causing hunting or turbulence.
Innovation Solution
Implementing an integral gain switching mechanism that transitions from a reference integral gain to a corrected integral gain during transient response periods, considering temperature changes in the control valve, to stabilize control and reduce settling time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the integral gain is increased to eliminate offset caused by thermal contraction, then the settling time is reduced, but hunting and turbulence occur causing control instability
Solution Approach 1:
The patent applies dynamics by making the integral gain adjustable rather than fixed. The system dynamically switches between a first integral gain (for normal operation) and a second integral gain (for transient response), allowing the control parameters to adapt to changing thermal conditions. This resolves the contradiction by enabling high gain only when needed for offset cancellation while maintaining stability during normal operation.
Solution Approach 2:
The patent changes the control parameter (integral gain) based on system state. By detecting transient response conditions and switching the integral gain value accordingly, the system optimizes performance for different operating conditions. This allows rapid offset cancellation during transients while preventing hunting during steady-state operation.
2Loss of time
If a high integral gain is constantly set to cancel offset rapidly, then the settling time is reduced, but the flow rate control becomes unstable due to overshoot and turbulence
Solution Approach 1:
The system dynamically adjusts the integral gain based on whether the system is in transient or steady-state operation. During transient response, a higher second integral gain is used to rapidly cancel offset. Once steady-state is achieved, the system switches to the first integral gain to maintain stable flow rate control. This dynamic adaptation resolves the contradiction between fast settling and stability.
Solution Approach 2:
The patent implements periodic switching between different integral gain values based on the system's operational phase. The controller periodically evaluates whether transient response is occurring and switches gain values accordingly, creating a rhythmic pattern of high-gain correction followed by low-gain stabilization that achieves both rapid settling and long-term stability.
3Reliability
If the integral gain is kept at reference value during transient response, then control stability is maintained, but offset cancellation is slow and settling time exceeds allowed time
Solution Approach 1:
The system dynamically switches to a second, higher integral gain specifically during transient response periods. This temporary increase in gain accelerates offset cancellation without compromising overall stability, as the system reverts to the reference gain once transient conditions subside. This resolves the contradiction by applying high gain only when and where it is needed.
Solution Approach 2:
The patent prepares multiple integral gain values in advance (first and second gains) and selects the appropriate one based on the system's operational state. By having the second higher gain ready for transient conditions, the system can immediately apply aggressive correction when needed, rather than gradually increasing gain during the transient period.
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 enables rapid cancellation of offset, reduces overshoot, and maintains control stability by adapting integral gain based on temperature fluctuations, thus shortening settling time and preventing hunting.
Implementation Method 1
a vaporizing portion (3) that vaporizes the liquid material by means of heating or decompression
Implementation Method 2
the temperature of the control valve decreased from the point in time when there was a rise in the flow rate of the liquid material, so that the required aperture could not be achieved due to thermal contraction of the metals forming the valve body and valve seat
Data Source
AI summary
A vaporization device is provided with a control valve on a flow path along which flows a liquid material, a vaporizing portion in which the liquid material is vaporized by decompression or heating, a liquid flow rate sensor that measures a flow rate of a liquid material flowing along the flow path, and a valve controller that controls the control valve using PI control or PID control that is based on a set value showing a set flow rate and on a measurement value of the flow rate that is measured by the liquid flow rate sensor. The vaporization device is configured to, during a transient response period of the flow rate that is measured by the liquid flow rate sensor, switch the integral gain set in the valve controller from a reference integral gain to a corrected integral gain that is different from the reference integral gain.