Introduction of SRT Limiting Oxygen Index Tester

1. Test Principle

The limiting oxygen index tester measures the minimum oxygen concentration (molar concentration) required to maintain the combustion of the sample after mixing O2 and N2. This instrument uses a mass flow controller to accurately control the flow of O2/N2, and mixes through a mixing chamber to fully ensure the accuracy of concentration control. It uses a British paramagnetic oxygen sensor to detect O2 concentration and has good performance. It is manufactured for test users with high accuracy requirements and can also meet the needs of general users.

2. Test Standards

This tester complies with but is not limited to the following standards:

GB/T 2406.2-2009, GB/T 5454-1997, GB/T 10707-2008, ISO 4589-2-2006, ASTM D2863-2000

3. Related terms

Oxygen index: The minimum oxygen concentration that just maintains the combustion of the material when a mixed gas of oxygen and nitrogen at 23±2℃ is introduced, expressed as a volume fraction.

4. Composition and use of the instrument

Display screen: for test operation, control and report query;

Power switch: Press the switch to turn on the power;

Emergency stop button: stop and cut off the power supply of the instrument in an emergency;

Ventilation switch: press to start ventilation, press again to stop ventilation;

Timing button: Press the burning timing button to start the burning timing;

O2, N2 pressure regulating switch: reduce the pressure of external gas to gas that can be used by the instrument;

O2, N2 pressure gauge: displays the gas pressure entering the instrument;

Combustion tube: The location where the combustion test is carried out, the top tube cover provides a stable gas flow;

Base: gas is introduced and the test sample is supported, equipped with glass beads and metal mesh;

Igniter: used to ignite the gas

Sampling should be carried out according to the material standard, and at least 15 specimens can be prepared from the samples taken. It can also be carried out according to GB/T 2828.1-2003 or ISO 2859-2:1985.

Note: For materials with known oxygen index fluctuations within ±2, 15 specimens are required. For materials with unknown oxygen index, or materials showing unstable combustion characteristics, 15 to 30 specimens are required.