Particle Concentration Control in Clean Room Test Chambers
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Solution Overview
Problem
In environments like clean rooms in semiconductor manufacturing factories, accurately controlling the quantity of particles in the air is challenging for particle detecting device evaluations, as existing methods lack precision in replicating particle concentrations for consistent testing.
Innovation Solution
An environment providing device with a test chamber, spraying device, flow meter, flow rate controlling device, timer, and spraying-device-controlling device is used to supply a gas flow, measure and control the flow rate, and stop particle spraying after a prescribed quantity is reached, ensuring consistent particle concentrations for accurate device evaluations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If particle quantity is controlled by manual spraying methods, then device complexity is reduced, but manufacturing precision of particle concentration deteriorates
Solution Approach 1:
The system uses a flow meter to measure the actual flow rate of gas supplied to the spraying device, and a flow rate controlling device adjusts the gas flow rate based on this measurement to maintain it at a prescribed value. This feedback control ensures precise particle concentration control by dynamically compensating for flow rate variations.
Solution Approach 2:
The invention replaces manual mechanical spraying control with an automated system that uses electronic flow measurement and control. The flow meter and flow rate controlling device substitute for manual operation, providing precise and repeatable particle concentration control without human intervention.
2Manufacturing precision
If spraying continues for fixed time interval, then ease of operation is improved, but manufacturing precision of particle quantity deteriorates
Solution Approach 1:
The timer measures the actual spraying time interval, and the spraying-device-controlling device stops spraying when the prescribed time has elapsed. This feedback mechanism ensures that spraying duration is precisely controlled, preventing over-spraying or under-spraying that would occur with manual timing.
Solution Approach 2:
The system pre-establishes the prescribed time interval for spraying before the actual spraying begins. The timer is set in advance, and the spraying-device-controlling device is configured to stop spraying automatically when this predetermined time is reached, eliminating the need for manual monitoring during the process.
3Manufacturing precision
If gas flow rate varies during spraying, then ease of operation is improved, but manufacturing precision of particle concentration deteriorates
Solution Approach 1:
The flow meter continuously measures the gas flow rate supplied to the spraying device, and the flow rate controlling device adjusts the flow rate based on this measurement to maintain it at the prescribed value. This feedback loop compensates for any variations in gas supply conditions, ensuring consistent particle concentration throughout the spraying process.
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 setup allows for precise control and repeatability of particle concentrations in the test environment, enabling reliable evaluations of particle detecting devices by maintaining uniform conditions across multiple tests.
Implementation Method 1
a flow meter for measuring a measured value for a flow rate of the gas flow that is supplied to the spraying device
Implementation Method 2
a spraying device for receiving a supply of a gas flow and spraying, into the test chamber, a fluid that contains particles
Data Source
AI summary
An environment providing device having a test chamber; a spraying device for receiving the supply of a gas flow to spray, into the test chamber, a fluid that contains particles; a flow meter for measuring a measured value for the flow rate of the gas flow that is supplied to the spraying device; a flow rate controlling device for controlling to a prescribed value, based on the measured value, the flow rate of the gas flow that is supplied to the spraying device; a timer for measuring a time interval over which the fluid that includes the particles has been sprayed into the test chamber; and a spraying-device-controlling device for stopping the spraying of the fluid that contains the particles after spraying a prescribed quantity of particles into the test chamber.