Flow Control Device Isolating Power Supply Circuits
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Solution Overview
Problem
Conventional flow controlling devices experience interference and stability issues due to shared power supply connections, leading to errors in flow setting values when multiple devices are connected, as the valve driving electric current affects the analog inputting circuit, causing complex interactions and instability in flow control.
Innovation Solution
The implementation of an isolating power supply circuit using an isolating DC-DC converter to separate the valve driving circuit from the analog inputting circuit and controlling device, along with a signal transmitting device like a photocoupler, to prevent interference and ensure accurate flow control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If multiple flow controlling devices are connected to a shared power supply without isolation, then device complexity and cost are reduced, but interference occurs between valve driving circuits and analog inputting circuits causing flow setting errors
Solution Approach 1:
The power supply system is segmented into two independent parts: an isolating power supply circuit for the analog inputting circuit and controlling device, and a non-isolating power supply circuit for the valve driving circuit. This segmentation prevents interference while maintaining separate power paths, resolving the contradiction between simplicity and reliability.
Solution Approach 2:
An isolating DC-DC converter is introduced as an intermediary component between the shared power supply and the analog inputting circuit. This intermediary provides electrical isolation, blocking interference from the valve driving circuit while still allowing power transmission, thus maintaining flow setting accuracy without requiring complete power supply separation.
2Reliability
If an isolating DC-DC converter is used to separate power supply circuits, then interference is eliminated and flow control stability is improved, but device complexity and cost increase
Solution Approach 1:
The isolating DC-DC converter is designed to serve multiple functions: providing electrical isolation, enabling bidirectional signal transmission through the isolated boundary, and maintaining power supply stability. This multi-functionality reduces the need for additional separate components, mitigating the increase in device complexity while achieving reliable flow control.
3Object-affected harmful factors
If high-capacity isolating converters are used to handle valve driving current, then interference is blocked, but device size and cost increase significantly
Solution Approach 1:
The harmful function of the isolating converter is extracted and separated from its power supply function. The converter is designed to block only the high-current interference path while allowing low-current control signals to pass through isolated channels. This extraction allows the use of smaller, lower-capacity isolating components that block interference without requiring high current handling capability.
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 solution eliminates self-interference and mutual interference between flow controlling devices, allowing for precise and stable flow control even when multiple devices are connected to a single setting device, reducing errors and costs associated with high-capacity converters.
Implementation Method 1
an isolating power supply circuit for isolating electrically the analog inputting circuit and the controlling device from the valve driving circuit
Implementation Method 2
a signal transmitting device like a photocoupler
Data Source
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AI summary
[Object] To provide a flow controlling device capable of providing an accurate flow set by a setting device without mutual interference between flow controlling devices. [Means of Resolution] A flow controlling device having a solenoid valve 20 for adjusting the opening of a flow path and a valve driving circuit 21 for driving the valve, comprising: an analog inputting circuit 23 for converting an inputted analog voltage value or analog electric current value into a specific digital value or analog value and then transmitting; a controlling portion 22 for nputting the digital value or analog value transmitted from the inputting circuit and outputting an instruction signal depending on the flow that has been set; a signal transmitting portion that electrically isolates the controlling portion and the valve driving circuit and sends, to the valve driving circuit, the instruction signal from the controlling portion; an isolating power supply circuit for electrically isolating the analog inputting circuit and the controlling portion and for supplying a power supply to the analog inputting circuit and the controlling portion; and a non-isolating power supply circuit for providing a power supply to the valve driving circuit.