Exhaust Gas Sampling System with Pressure Compensation
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Solution Overview
Problem
Existing exhaust gas sampling and analysis systems face challenges in maintaining measurement accuracy when dealing with high-pressure exhaust gases, as changes in flow rate and pressure are difficult to manage, leading to reduced analysis quality.
Innovation Solution
The system incorporates a main flow channel with a flow restriction mechanism, a measurement flow channel, a compensation flow channel, and a flow rate adjustment mechanism to depressurize the exhaust gas and adjust the compensation gas flow rate, ensuring the pressure and flow rate of the exhaust gas are within the analysis device's specifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a critical venturi and suction pump are used to maintain constant total flow rate of dilution gas, then the flow pressure stability is improved, but the system cannot cope with changes in exhaust gas flow rate, especially high pressure exhaust gas
Solution Approach 1:
The patent introduces a flow rate adjustment mechanism that dynamically adjusts the opening degree of a flow restriction valve based on the actual exhaust gas flow rate. This dynamic adjustment allows the system to adapt to changing exhaust gas conditions while maintaining stable flow pressure to the analysis device, resolving the contradiction between pressure stability and adaptability.
Solution Approach 2:
The system incorporates a flow rate detection mechanism that continuously monitors the exhaust gas flow rate and provides feedback to the flow rate adjustment mechanism. This feedback loop enables automatic adjustment of the flow restriction valve to maintain optimal operating conditions, allowing the system to handle both stable and variable exhaust gas flow rates effectively.
2Manufacturing precision
If a pump of constant volume type is used to keep total amount and pressure of diluted exhaust gas constant, then the flow rate and pressure control is improved, but the system cannot sample high pressure exhaust gas
Solution Approach 1:
The patent divides the flow control function into two independent segments: a flow rate adjustment mechanism that handles the variable flow rate control, and a separate pressure control mechanism that maintains constant pressure to the analysis device. This segmentation allows the system to independently optimize both flow rate adaptability and pressure control precision, enabling sampling of high pressure exhaust gas while maintaining measurement accuracy.
Solution Approach 2:
The patent introduces a flow restriction valve as an intermediary component between the exhaust gas source and the analysis device. This intermediary element provides a adjustable flow restriction that, when combined with the flow rate adjustment mechanism, enables the system to handle high pressure exhaust gas by controlling the flow rate through the restriction valve while maintaining downstream pressure stability.
3Stability of the object's composition
If atmospheric air path is connected to reduce flow pressure change in exhaust gas analysis device, then the flow pressure stability is improved, but the flow rate of sampled exhaust gas changes when atmospheric air flow rate changes
Solution Approach 1:
The patent extracts the atmospheric air path from the main exhaust gas flow path, creating a separate parallel pathway. This separation allows the atmospheric air to be introduced independently to control pressure fluctuations without directly affecting the exhaust gas flow rate measurement, thereby maintaining both pressure stability and flow rate measurement accuracy.
Solution Approach 2:
The system uses the flow rate adjustment mechanism to dynamically change the opening degree of the flow restriction valve based on detected exhaust gas flow rate conditions. This parameter adjustment ensures that the flow rate of sampled exhaust gas remains stable and accurate while the atmospheric air path handles pressure regulation, resolving the contradiction between pressure stability and flow rate measurement precision.
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 arrangement allows for accurate analysis of high-pressure exhaust gases without reducing measurement accuracy, enabling effective sampling and evaluation of filter performance, particularly in scenarios where upstream pressures are high due to clogging.
Implementation Method 1
a flow restriction mechanism arranged on the main flow channel, a measurement flow channel that extends from the main flow channel in the downstream of the flow restriction mechanism
Implementation Method 2
a first suction pump connected to the main flow channel in order to introduce the exhaust gas into the main flow channel
Implementation Method 3
a flow rate adjustment mechanism that is arranged on the compensation flow channel and that adjusts a flow rate of the compensation gas to be supplied to the main flow channel
Implementation Method 4
a measurement flow channel that extends from the main flow channel in the downstream of the flow restriction mechanism and that samples and circulates the exhaust gas flowing in the main flow channel
Data Source
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AI summary
This invention intends to analyze a component of an exhaust gas without a reduction in a measurement accuracy by sampling a high pressure exhaust gas. An exhaust gas sampling and analysis system of this invention is provided with: a main flow channel (2) in which a flow restriction mechanism (3) and a first suction pump (P1) are arranged; a measurement flow channel (4) in which an exhaust gas analysis device (5) is provided and that extends from the main flow channel (2) at a position downstream of the flow restriction mechanism (3); and a compensation flow channel (6) in which a flow rate adjustment mechanism (MFC3) is provided and that extends from the main flow channel (2) at a position downstream of the point from which the measurement flow channel (4) extends. The first suction pump (P1) further reduces the pressure of the exhaust gas having a pressure which is reduced when the exhaust gas passes through the flow restriction mechanism (3). The flow rate adjustment mechanism (MFC3) adjusts, in order that the pressure of the exhaust gas at the point from which the measurement flow channel (4) extends is a predetermined value, the flow rate of the compensation gas supplied to the main flow channel (2).