Shielding Gas Flow Sensing for Mixed-Gas Welding Control
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Solution Overview
Problem
Existing methods for measuring shielding gas flow rates in gas metal arc welding are inadequate for continuous monitoring and require inconvenient intermittent measurements, especially when dealing with a wide variety of shielding gas mixtures, and lack integration with welding equipment.
Innovation Solution
A compact, mobile sensor apparatus using thermal mass flow sensors integrated into the shielding gas distribution system near the nozzle, which continuously measures flow rates by employing thermal mass flow sensors, a control unit, and calibration data to determine the flow rate of gas mixtures based on their composition and thermodynamic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If intermittent flow rate measurements are conducted with temporary flow sensors near the gas nozzle, then flow rate data can be obtained for different gas mixtures, but the measurements are inconvenient and yield much less information than continuous measurement would
Solution Approach 1:
The patent implements continuous flow rate measurement by integrating a flow sensor into the shielding gas distribution system, allowing uninterrupted monitoring of gas flow throughout the welding process. This eliminates the need for intermittent manual measurements and provides continuous data for process optimization.
Solution Approach 2:
The system automatically performs flow rate measurements and provides feedback without requiring manual intervention. The integrated sensor continuously monitors the gas flow and the control unit processes the data, enabling the system to self-regulate and provide information without operator involvement in the measurement process.
2Measurement precision
If flow rate measurements are conducted relatively close to the gas nozzle, then leakage of shielding gas can be detected, but the sensor apparatus should be relatively small and mobile without hindering the welding process
Solution Approach 1:
The flow sensor is integrated into the existing shielding gas distribution system at strategic points, segmenting the measurement function from the main welding apparatus. This allows the sensor to be positioned close to the nozzle for accurate measurement while maintaining the mobility and simplicity of the overall welding system.
Solution Approach 2:
The flow sensor is merged with the shielding gas distribution system, combining the gas delivery function with the measurement function. This integration allows the sensor to be positioned optimally for measurement while sharing the system infrastructure, reducing overall complexity and avoiding additional mobile equipment.
3Productivity
If continuous flow rate measurements are implemented, then shielding gas usage can be monitored and optimized, but equipment for continuous flow rate measurements must be integrated with the welding equipment
Solution Approach 1:
The flow sensor and control unit are designed to be universally compatible with the shielding gas distribution system, serving multiple functions including flow measurement, process monitoring, and optimization. This multi-functionality reduces the need for separate dedicated equipment and simplifies integration with existing welding systems.
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
Enables continuous, accurate monitoring and adjustment of shielding gas flow rates during welding, improving process control and reducing gas usage inefficiencies by accounting for the specific composition and properties of various gas mixtures.
Implementation Method 1
thermal mass flow sensors connected to one or more sensor channels
Data Source
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AI summary
The disclosure relates to a sensor apparatus and a method for measuring the flow rate of a shielding gas in a welding apparatus. The sensor apparatus comprises at least one inlet and at least one outlet in fluid connection with one or more bypass channels and with one or more sensor channels, and at least one input hose and one output hose. The apparatus also comprises one or more thermal mass flow sensors connected to the one or more sensor channels, and a control unit configured to retrieve sensor responses from the one or more thermal mass flow sensors and to determine the flow rate of the shielding gas through the sensor apparatus based on the retrieved sensor response and calibration data, wherein the calibration data comprises one or more characteristic curves comprising gas flow values and sensor response values. The control unit is configured to retrieve from a memory unit: the composition of the shielding gas; the number of active thermodynamic degrees of freedom which the molecules of each gas component in the shielding gas possess at the retrieved shielding gas temperature; a characteristic curve for each gas component separately, which consists of sensor response data as a function of gas flow rate, measured in a calibration experiment conducted with a pure gas consisting only of that gas component. The control unit is configured to calculate a new, mixture-specific characteristic curve for the gas mixture as a weighted average of the pure-gas characteristic curves, wherein the weight assigned to each value on a pure-gas characteristic curve is a product of the concentration percentage of that gas component in the shielding gas mixture and the number of active thermodynamic degrees of freedom which the molecules of that gas component possess at the retrieved shielding gas temperature; and to use the mixture-specific characteristic curve as the characteristic curve for the shielding gas mixture by retrieving from this characteristic curve the calibration gas flow rate which corresponds most closely to the retrieved new sensor response; and to identify this flow rate as the current flow rate of the shielding gas through the sensor apparatus. The sensor apparatus also comprises a display unit configured to display the determined flow rate of the shielding gas to a user and/ or a memory unit for storing the determined flow rate of the shielding gas.