In-Situ Gas Analysis Seal for Reduced Test Gas Consumption
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Solution Overview
Problem
Existing optical in-situ gas analysis apparatuses face challenges with high particulate loads in exhaust gases, leading to impaired measurements and high test gas consumption due to porous filters, which are costly and require frequent calibration.
Innovation Solution
The apparatus employs a seal that can be expanded to close openings in the measuring lance, allowing for a controlled introduction of test gas through a small leak, minimizing test gas consumption and ensuring even path filling, independent of measurement path length, with a gas-permeable filter to prevent particulates from entering the measurement path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a porous filter is used to keep particulates out of the measurement path, then measurement reliability is improved, but test gas consumption increases
Solution Approach 1:
The system is divided into a measurement mode with open filter and a calibration mode with closed filter. The seal divides the openings into sealed and unsealed portions, allowing selective operation modes that optimize both measurement reliability and test gas consumption
Solution Approach 2:
The seal is moved between first and second positions to periodically switch between measurement mode (filter open) and calibration mode (filter closed). This periodic switching allows the system to maintain measurement reliability while minimizing test gas consumption to only when necessary
2Measurement precision
If the measurement path is made longer to improve measurement precision, then measurement precision is improved, but test gas consumption increases
Solution Approach 1:
The seal position is dynamically adjusted between first and second positions based on operational requirements. During calibration, the seal closes the filter regardless of its length, and during measurement, the seal opens the filter. This dynamic positioning allows long measurement paths for precision while minimizing test gas consumption during calibration
3Loss of substance
If the seal closes the openings completely to minimize test gas consumption, then test gas consumption is reduced, but gas exchange between measurement path and exhaust gas passage is impaired
Solution Approach 1:
The seal is designed to close only a portion of the openings (first position) rather than completely sealing them (second position). This local sealing approach minimizes test gas consumption while maintaining sufficient gas exchange through the unsealed portions, balancing test gas reduction with measurement functionality
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 significantly reduces test gas consumption, maintains predictable and constant gas exchange, and extends the service life of the apparatus by minimizing mechanical wear and allowing for automatic or manual operation, while effectively preventing particulates from interfering with measurements.
Implementation Method 1
The seal comprises a strip of elastic material whose volume is variable and which increases its volume in order to close the openings
Implementation Method 2
a light transmitter that is arranged in the housing and whose light is conducted into the measuring lance and is reflected by a reflector arranged at the second end onto a light receiver
Implementation Method 3
reflected by a reflector arranged at the second end onto a light receiver
Implementation Method 4
a gas-permeable filter to prevent particulates from entering the measurement path
Implementation Method 5
Due to the porous structure, the gas to be measured can admittedly move into the measurement path; however, particulates such as smoke, dusts or aerosols can also be kept away depending on the pore size
Data Source
AI summary
An apparatus for optical in-situ gas analysis includes: a housing; a measuring lance a first end connected to the housing and a second end projecting into the gas to be measured; a light transmitter that is arranged in the housing and whose light is conducted into the measuring lance and is reflected by a reflector arranged at the second end onto a light receiver, and the optical path defines an optical measurement path within the measuring lance; and, an evaluation device for evaluating received light signals of the light receiver. In order to be able to reduce the consumption of test gas, the measuring lance has an outer tube, with the outer tube having openings for the gas to be measured. The openings can be closed by at least one seal for the test phase, with the seal searingly closing the openings by the enlargement of its volume.