Nitrogen Dioxide Sterilization System Sequential Gas Filling
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Solution Overview
Problem
Existing sterilization methods using nitrogen oxide gas are not effective for sterilizing large, wide spaces with low concentrations of nitrogen dioxide, particularly in environments with people, as they require high concentrations and long times, and lack uniformity.
Innovation Solution
A sterilization system that includes a gas supply source for nitrogen dioxide gas, a piping system with valves, and a concentration sensor to control the gas filling process, allowing each space to be filled sequentially with nitrogen dioxide gas for a predetermined time, with the system excluding spaces that reach the target concentration from further filling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high concentration of nitrogen dioxide gas is used for sterilization, then sterilization effect is improved, but safety deteriorates due to harmful effects on humans
Solution Approach 1:
The sterilization process is divided into multiple sequential cycles, with the space being filled with nitrogen dioxide gas in stages rather than all at once. The control device manages multiple filling cycles, allowing concentration buildup while maintaining safety through controlled exposure levels in each cycle.
Solution Approach 2:
The sterilization is performed through periodic cycles of gas filling and concentration monitoring. The control device repeatedly fills the space with nitrogen dioxide gas, monitors concentration, and pauses when target concentration is reached, creating a periodic action pattern that achieves sterilization while managing safety.
2Productivity
If nitrogen dioxide gas is filled continuously into multiple spaces, then filling speed is improved, but concentration uniformity deteriorates
Solution Approach 1:
The gas filling process is segmented into multiple sequential cycles rather than continuous filling. Each cycle fills the space for a predetermined time, then pauses for concentration monitoring, ensuring uniform distribution before the next filling phase.
Solution Approach 2:
Before each gas filling cycle, the system performs preliminary concentration monitoring to determine the current state of the space. This preliminary action allows the control device to adjust subsequent filling cycles to achieve uniform concentration distribution.
3Reliability
If long exposure time is used for sterilization of wide spaces, then sterilization completeness is improved, but productivity deteriorates
Solution Approach 1:
The sterilization process uses periodic cycles of gas filling and concentration monitoring. Each cycle fills the space for a predetermined time, then pauses to monitor concentration levels. This periodic approach achieves complete sterilization through cumulative exposure while improving productivity by avoiding unnecessary continuous filling.
Solution Approach 2:
The control device monitors nitrogen dioxide gas concentration and uses this feedback to control the filling cycles. When the target concentration is detected, the system adjusts subsequent cycles accordingly, ensuring complete sterilization while optimizing the total exposure time for productivity.
Data Source
AI summary
The sterilization system includes a plurality of spaces to be sterilized by a sterilization process; a gas supply source generating nitrogen dioxide gas; a piping system and a valve device; a nitrogen dioxide gas sensor; and a control device. The control device performs a gas filling process in which each of the plurality of spaces to be sterilized is connected to the gas supply source one by one for a first predetermined length of time and successively filled with the nitrogen dioxide gas by controlling the valve device, and when the concentration of the nitrogen dioxide gas in a space to be sterilized that is being filled with gas is detected by the sensor to have reached a predetermined level, the control device performs control such that the subsequent gas filling process is performed with this space to be sterilized being excluded from the gas filling process.