Trace oxygen analyzer is divided into two analysis principles: fuel cell method trace oxygen analyzer and zirconia trace oxygen analyzer. The following editor will tell you some precautions.

Trace oxygen analyzer supporting pipeline

Sealing should be ensured. Small leaks will diffuse the oxygen in the ambient air, which will make the measured value higher.

Although in the measurement, the sample gas pressure is greater than the ambient pressure, the oxygen in the sample gas is at a trace level. According to Ferrari’s law, the partial pressure of oxygen is proportional to its volume content. The atmosphere contains about 21% oxygen, which is comparable to PPM The oxygen partial pressure of the calculated concentration of the sample gas differs by about 10,000 times, so the partial pressure of the trace oxygen in the gas sample is much lower than the partial pressure of oxygen in the atmosphere. When a leak occurs, the oxygen in the atmosphere will rapidly diffuse from the leaked part Come in.

In addition, the sampling pipeline should be as short as possible, and the number of joints should be as few as possible, and the joints and valves should be well sealed. After the pipeline is connected, the air tightness should be checked.

Airtightness inspection requirements: under 0.25MPAm test pressure, 30 minutes, the pressure drop is not more than 0.01MPA.

Micro oxygen analyzer pipeline material

Basically, copper or stainless steel pipelines are better, and PTFE pipes are the second choice. Forbidden to select latex tube, white rubber tube and other pipes, their air tightness and material permeability are too poor, and the error of measuring trace oxygen under standard measurement pressure is too large. The outer diameter of the pipeline is usually 6 mm or 1/4 IN, or 3 mm or 1/8 IN. In short, stainless steel pipe is preferred. Clean and degrease to keep the inner wall of the pipe smooth and clean. For the analysis of trace level (<1PPMV) oxygen, Stainless steel pipe with polished inner wall should be selected. The dead volume of the selected valve and joint should be as small as possible.

Trace oxygen analyzer sample

The moisture in the water condenses and condenses on the pipe wall, causing the dissolution and absorption of trace oxygen. The sampling pipeline should be insulated and heat-preserved according to the situation. When detecting trace oxygen in liquid nitrogen, special attention should be paid to heating measures. Otherwise, because the boiling point of oxygen is 13 degrees lower than the boiling point of nitrogen, the sample gas is not uniformly vaporized, which will seriously lower the measured value.

The sample gas should not contain oily components or solid particles, so as not to cause blockage and pollution of the permeable membrane.

The sample gas should not contain sulfide, phosphide or acid gas components. These components can cause harm to fuel cells, especially alkaline fuel cells.

Principles of trace oxygen analyzer

The measurement position of the trace oxygen analyzer should be as close as possible to the measurement unit to avoid excessively long pipelines and too many uncertain factors that affect the reliability of the measurement data.

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