Flow Rate Valve Control for Accurate Accumulated Volume Shutoff
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Solution Overview
Problem
Existing flow rate control devices face challenges in accurately closing valves with minimal accumulated flow rate error due to delays and variations in pressure and instantaneous flow rate, especially when the valve functions as both a flow rate regulating and closing valve, leading to inaccuracies and poor reproducibility.
Innovation Solution
A flow rate control device comprising a flow rate meter, a flow rate regulating valve, and a control unit that monitors the valve's opening degree and instantaneous flow rate, allowing for early closure based on a calculated 'early closing flow rate value' to minimize errors, and includes a low flow rate rapid valve opening function and overshoot suppression to enhance control precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the valve is closed after the accumulated flow rate value is reached, then the valve closing operation is simple, but the accumulated flow rate value error increases due to delay time
Solution Approach 1:
The control unit starts the valve closing operation in advance before the accumulated flow rate reaches the target value. By calculating the delay time based on the relationship between valve opening degree and closing time, the system predicts when the valve will fully close and initiates closing earlier, ensuring the valve is fully closed exactly when the target accumulated flow rate is reached, thus eliminating accumulated flow rate error.
Solution Approach 2:
The control unit continuously monitors the actual accumulated flow rate and compares it with the target value. Based on this feedback and the measured delay time, the system dynamically adjusts the timing of the closing operation, creating a closed-loop control that compensates for variations in valve closing time and ensures accurate flow rate control.
2Device complexity
If one valve functions as both flow rate regulating valve and close valve, then device complexity is reduced, but the time until valve is closed increases leading to larger accumulated flow rate value error
Solution Approach 1:
The patent employs a single valve that performs both flow rate regulation and closing functions. The control unit manages this multi-functional valve by measuring the delay time from closing initiation to full closure and using this information to predict and compensate for closing time variations, enabling accurate flow rate control despite the valve's dual role.
Solution Approach 2:
The control unit calculates the delay time based on the valve opening degree and starts the closing operation in advance. This preliminary action compensates for the longer closing time inherent in multi-functional valves, ensuring that the valve fully closes at the precise moment the target accumulated flow rate is reached.
3Adaptability or versatility
If the valve opening degree is adjusted according to pressure conditions and instantaneous control flow rate, then flow rate control flexibility is improved, but the accumulated flow rate error varies making accurate closure difficult
Solution Approach 1:
The control unit dynamically adjusts the valve opening degree based on pressure conditions and instantaneous flow rate requirements. Simultaneously, it measures the actual delay time for each opening degree and uses this dynamic information to calculate the appropriate early closing timing, ensuring accurate flow rate control despite varying operating conditions.
Solution Approach 2:
The system changes the valve opening degree parameter according to pressure conditions and flow rate requirements. The control unit compensates for the resulting variations in closing time by calculating delay time for each opening degree and adjusting the closing initiation timing accordingly, maintaining accuracy across different operating parameters.
Data Source
AI summary
Provided is a flow rate control device capable of improving accumulated flow rate error. The flow rate control device of the present disclosure includes: a flow rate meter that measures a flow rate of a fluid flowing through a flow path; a flow rate regulating valve that regulates the flow rate of the fluid flowing through the flow path; and a control part that controls an opening degree of the flow rate regulating valve based on a measurement result of the flow rate meter, includes: a closing function that controls the opening degree of the flow rate regulating valve with an instantaneous flow rate value and closes with a set accumulated flow rate value; and an accumulated value prediction function that monitors the current opening degree of the flow rate regulating valve and the instantaneous flow rate value all the time, and starts a closing operation of the flow rate regulating valve at a time point when the accumulated flow rate value reaches an early closing flow rate value.