Gas Sampling Pressure Control for Stable Methane Measurement

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Solution Overview

Problem

Gas analysis devices face challenges in maintaining a constant flow rate of sample gas due to variations in pressure and flow rate, leading to inconsistent methane concentration measurements.

Innovation Solution

Incorporating a pressure loss mechanism and a pressure control mechanism that controls pressure differences in the sample gas line by discharging a portion of the sample gas or supplying a predetermined gas, ensuring a constant flow rate and mixture ratio, thereby stabilizing the analysis of sample gas components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a sampling pump is used to capture sample gas, then the sample gas can be drawn into the analysis device, but the flow rate varies due to pulsations causing measurement inconsistency

Engineering Contradiction:
Improvesample gas capture capabilityVSAvoidmethane concentration measurement accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

A buffer tank is introduced as an intermediary component between the sampling pump and the analysis device. The buffer tank receives pulsating sample gas flow from the pump and provides a stabilized, continuous flow to the analyzer, thereby decoupling the pump's pulsations from the measurement system and improving measurement precision while maintaining productivity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The buffer tank acts as a cushioning element that absorbs flow variations beforehand. By providing a reservoir that smooths out pulsations before the gas reaches the analyzer, the system prepares a stable flow condition in advance, preventing measurement errors caused by flow variability

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Measurement precision

If pressure control mechanism is added to maintain constant flow rate, then measurement accuracy improves, but device complexity increases

Engineering Contradiction:
Improvecomponent analysis accuracyVSAvoidpressure control system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The buffer tank is designed as a passive, self-regulating component that automatically smooths flow variations without requiring external control systems. The tank's volume and geometry provide inherent flow stabilization, eliminating the need for complex active pressure control mechanisms while maintaining measurement precision

Inventive Principle:
Principle #25Self-service

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 approach allows for accurate analysis of sample gas components by maintaining a consistent flow rate and mixture ratio, even with variations in pressure, enhancing the precision of methane concentration measurements.

Implementation Method 1

a pressure loss mechanism that is provided on the sample gas line, a pressure control mechanism that controls pressure differences in the sample gas line between a front and a rear of the pressure loss mechanism

Methodology Applied
Scientific EffectPressure difference: Pressure Gradient

Implementation Method 2

one method of measuring methane contained in a sample gas such as exhaust gas or the like is to cause the sample gas to pass through a non-methane cutter so that hydrocarbons excluding methane that are contained in the sample gas are combusted inside the non-methane cutter

Methodology Applied
Scientific EffectCombustion: Combustion

Data Source

PatentEP3336539B1Gas analysis device, gas sampling device and gas analysis method
Publication Date: 2023.08.30 HORIBA LTD
  • EP3336539B1 patent drawingFigure 1
  • EP3336539B1 patent drawingFigure 2
  • EP3336539B1 patent drawingFigure 3

AI summary

A gas analysis device is provided that is able to accurately measure a concentration or a quantity of methane contained in a sample gas even if there are variations in the pressure in the sample gas line. This gas analysis device 1 has a sample gas line 11 through which a sample gas flows, a pressure loss mechanism 20 that is provided on the sample gas line 11, a pressure control mechanism 21 that refers to the pressure on the forward side of the pressure loss mechanism and, by either discharging a portion of the sample gas from the rearward side of the pressure loss mechanism 20, or by supplying a predetermined gas to the rearward side of the pressure loss mechanism 20, controls pressure differences in the sample gas line 11 between the front and the rear of the pressure loss mechanism 20, and an analyzer that analyzes the sample gas flowing through the sample gas line 11.