Gas Supply Device MFC Calibration via Pressure Increase Test
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Solution Overview
Problem
Existing coating systems face challenges in maintaining accurate dosing of process gases over time, leading to potential deviations in coating quality due to the degradation of Mass Flow Controllers (MFCs, with no simple methods for monitoring or correcting the delivery of desired gas mixtures, especially in high-production environments.
Innovation Solution
A device with two base gas lines and mixing means, equipped with MFCs upstream of a mixing agent and an evaporator to convert liquid starting components into gases, along with a reference device for conducting pressure increase tests to verify MFC calibration and adjust as needed, ensuring accurate gas mixture composition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If MFCs are used to meter base gases in coating systems, then gas dosing can be controlled, but dosing accuracy deteriorates over time due to MFC calibration loss
Solution Approach 1:
The patent implements preliminary action by performing regular pressure increase tests on MFCs to detect calibration drift before it significantly impacts coating quality. The system proactively monitors MFC performance through scheduled tests rather than waiting for coating defects to manifest, allowing early intervention and adjustment of dosing parameters.
Solution Approach 2:
The patent establishes a feedback mechanism where pressure increase test results are used to detect MFC calibration status and trigger appropriate responses. The system continuously monitors MFC performance through pressure measurements, compares results against expected values, and provides feedback for recalibration or replacement decisions, creating a closed-loop control system for gas dosing accuracy.
2Reliability
If coating quality is monitored to detect MFC dosing issues, then coating defects can be identified, but the effort and complexity increase significantly
Solution Approach 1:
The patent introduces an intermediary measurement approach by using pressure increase tests as a intermediate check between MFC dosing and final coating quality. Instead of directly monitoring complex coating properties, the system uses pressure measurements as an intermediary indicator of MFC performance, which is simpler to measure and provides earlier warning of potential quality issues.
Solution Approach 2:
The patent replaces complex coating quality measurement systems with a simpler pressure-based monitoring system. Instead of using sophisticated optical or chemical analysis to detect coating defects, the system substitutes a mechanical pressure measurement approach that is easier to implement and interpret, reducing overall system complexity while maintaining reliability.
3Measurement precision
If MFC calibration is verified through pressure increase tests, then dosing accuracy can be maintained, but additional monitoring equipment and procedures are required
Solution Approach 1:
The patent applies universality by designing the pressure measurement system to serve multiple functions: it monitors MFC calibration status, detects leaks in the gas delivery system, and provides data for troubleshooting coating issues. This multi-functional approach justifies the added monitoring equipment by demonstrating its broad utility across different system aspects.
Solution Approach 2:
The system implements self-service by using the existing gas delivery infrastructure and simple pressure measurements to automatically monitor MFC performance. The pressure increase tests utilize the MFC's own gas delivery capability to perform the calibration verification, eliminating the need for separate complex testing equipment and reducing overall system complexity.
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 enhances the monitoring and quality control of process gas delivery, allowing for timely adjustments to maintain desired coating properties, thereby improving the consistency and reliability of the coating process.
Implementation Method 1
at least one evaporator (131, 132) which is configured and designed to convert a liquid starting component into a gaseous base gas
Implementation Method 2
the reference device (180) is provided with a pressure sensor (190) for detecting a pressure within the reference volume (180)
Data Source
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AI summary
The invention relates to devices (100) for supplying a system (10) for coating workpieces (5) with the required process gases for the coating process taking place on the system (10), wherein the device has at least two base gas lines (124, 125; 102, 104) for separately guiding at least two base gases in one flow direction and at least one mixing agent (171, 172, 173) for combining and mixing at least two of the base gases to form a gas mixture.For metered supply of the base gases to the mixing medium (171, 172, 173), a mass flow controller (MFC; 141, 142, 143; 146, 147, 148) is arranged in the base gas lines (102, 104; 124, 125) in the flow direction of the supplied base gases upstream of the mixing medium (171, 172, 173), wherein the device for providing a first base gas has at least one evaporator (112, 114) which is set up and designed to convert a liquid starting fluid into the gaseous state. At least the MFC (141, 142, 143), which metered the base gas formed from a liquid starting fluid to the mixing agent (171, 172, 173), is kept at a condensation-preventing temperature greater than or equal to the boiling temperature.According to the invention, the device has a reference device (180) which provides a reference volume of known size and which is also kept at a condensation-avoiding temperature greater than or equal to the boiling point, wherein the reference device (180) has a pressure sensor (190) for detecting the pressure in the reference volume, wherein the reference volume is connected via a pump line (185) controlled by a switchable valve (187) to a pump device (160) for generating a vacuum in the reference volume, and wherein the MFC (141, 142, 143) kept at the condensation-avoiding temperature is connected to the reference volume via a reference line (195) controlled by a switchable valve (197).