Fluid Flow Rate Output Switching for Closed-to-Open Valve Transitions
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Solution Overview
Problem
Conventional fluid control devices exhibit unnatural behavior, such as negative flow rates, when switching from a closed to an open state, due to factors like backflow and pressure changes caused by seat leaks or sensor failures.
Innovation Solution
A fluid control device with an actual flow rate calculation unit, a flow rate output unit, and a switching unit that outputs a zero value when the fluid control valve is closed and switches to the calculated flow rate when the valve is open and a pressure difference exceeds a predetermined threshold, preventing negative outputs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the output is simply switched from zero value to calculated flow rate when the fluid control valve transitions from closed to open state, then the device responds quickly to valve opening, but the output behaves unnaturally with negative flow rates immediately after switching
Solution Approach 1:
The patent applies preliminary action by checking the pressure difference between upstream and downstream sides before switching from zero output to calculated flow rate output. The switching unit verifies that the pressure difference exceeds a predetermined threshold before allowing the transition, ensuring that the fluid path is properly established and preventing negative flow rate outputs that would occur with simple immediate switching.
2Reliability
If the zero output function is continuously applied when the fluid control valve is closed, then negative outputs are prevented, but abnormal values caused by seat leaks or sensor failures cannot be detected promptly
Solution Approach 1:
The patent applies dynamics by making the zero output function dynamic rather than static. The switching unit continuously monitors the pressure difference and automatically switches between zero output mode and calculated flow rate output mode based on real-time pressure conditions. When the pressure difference exceeds the threshold, the system transitions to calculated output, enabling detection of abnormal values while maintaining reliability under normal closed-valve conditions.
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
This configuration prevents unnatural behavior by ensuring a smooth transition from zero to calculated flow rate, while also allowing abnormal values to be detected promptly by stopping the zero output function under specific conditions.
Implementation Method 1
an upstream pressure sensor, and a downstream pressure sensor on a flow path
Implementation Method 2
an actual flow rate calculation unit configured to calculate a flow rate based on measured pressures of the upstream pressure sensor and the downstream pressure sensor
Data Source
AI summary
In order to prevent unnatural behavior of a calculated flow rate, provided is a fluid control device in which a fluid control valve and upstream and downstream pressure sensors are provided on a flow path. The device includes a calculation unit configured to calculate a flow rate based on measured pressures; and an output unit configured to output the calculated flow rate, and exhibit a zero output function of outputting a zero value regardless of the calculated flow rate when the valve is in a closed state. The device is further configured to switch between execution and stop of the zero output function, and when the valve is in an open state and a difference between the measured pressures of the pressure sensors is larger than a threshold, stop the zero output function and cause the flow rate output unit to output the calculated flow rate.