Introduction of limiting oxygen index instrument

1.1 test principle

The loi tester is a mixture of O2 and N2 that measures the low oxygen concentration (molar concentration) of zui required to maintain sample combustion. The mass flow controller is used to accurately control the flow rate of O2/N2. Mixing through the mixing chamber can fully ensure the accuracy of concentration control. The paramagnetic oxygen sensor is adopted in Britain to detect O2 concentration, and the performance is good. It can also meet the requirements of general users.

1.2 test standards

The glawing wire tester meets 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

1.3 related terms

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

1.4 composition and use of the instrument

Display screen: test operation, control and report inquiry;

Power switch: press the switch to switch on the power;

Emergency stop button: stop cutting off the power of the instrument in case of emergency;

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

Timing button: press the combustion timing button to start the combustion timing;

O2, N2 pressure adjustment switch: the external gas into the instrument can be used gas;

2, N2 pressure gauge: shows the gas pressure into the instrument;

Combustion tube: the place where the combustion test is conducted. The top tube cover provides stable gas flow.

Base: air is injected and the test sample is supported. Glass beads and metal mesh are installed.

Igniter: used to ignite gases

Samples should be taken according to the material standard and at least 15 samples can be prepared. Also available in GB/T 2828.1-2003 or ISO 2859-2:1985.

Note: for materials whose oxygen index is known to fluctuate within ±2, 15 samples are required. For materials with unknown oxygen index, or materials showing unstable combustion characteristics, 15 ~ 30 samples are required.