Usage of oxygen index tester

Usage of oxygen index tester

We know that oxygen index tester is mainly used to determine the combustion performance of wire and cable wire testing equipment, according to GB2406 "plastic combustion performance test method, the oxygen index method" regulation, we know that the oxygen index test of each step, the requirements of the sample, the burning time and so on are all have certain rules, will share with you today about the oxygen index apparatus of method of use:

According to GB2406, measure and clamp the plastic that can stand upright at the lower end, the sample combustion time is 3min, and draw a standard line from the wide surface of the sample to 50mm from the ignition end. When the sample's combustion time exceeds 3min or the flame front exceeds the standard line, the oxygen concentration will be reduced; when the sample's combustion time is less than 3min or the flame front is less than the standard line, the oxygen concentration will be increased, and so on, until the difference between the oxygen concentration obtained by the two is less than 0. 5.

Preparation before the operation of the oxygen index experimental instrument:

1. The operator is required to calibrate the oxygen index tester before the test to ensure the accuracy of the test data. Conduct the test after calibration, and the test requires at least 15 standard samples, mark 50mm at either end of the sample, and insert the other end into the combustion tube inside the sample clip for the test (different forms, different thickness of the sample, the test results can not be compared).

2. Determine the concentration of primary oxygen before the oxygen index tester is tested. If uncertain, the sample can be ignited in the air, pay attention to observe the combustion. If the sample burns quickly, the initial concentration of oxygen is selected to be 18. If the sample ignites in the air and immediately goes out from the fire, the oxygen concentration of 25 or higher is selected according to the difficulty of ignition.

Operation steps of oxygen index tester:

Firstly, open the valve doors of oxygen and nitrogen bottles and adjust the pressure reducing valve to 0.2~0.3Mpa. Adjust trace regulator, to stable the velocity of oxygen and nitrogen gas flow through the rotor flowmeter instructions, see the float on the surface, and adjust to the work place, at the same time check whether instrument gauge at 0.1 Mpa, otherwise, shall, in accordance with the provisions of regulation to the pressure, the N2 + O2 pressure gauge is not greater than 0.03 Mpa or does not display the pressure is normal, more than the pressure should check whether there is burning the column charcoal, gas road jams phenomenon, until meet the requirements. Before testing or changing the oxygen concentration, the system must be flushed for 30s.

After washing the oxygen index tester system, ignite the sample with propyl, butane or natural gas, and the flame length is 6~25mm. After lighting the upper end of the sample, remove the ignition source immediately and start timing immediately.

In the process of sample combustion, observe the combustion of the sample. If the sample burns more than 180s or 50mm, it indicates that the oxygen concentration is too high and must be reduced. If the sample is extinguished before 180s or 50mm, the oxygen concentration must be increased. The volumetric percentage concentration of oxygen must be measured when the sample is extinguished exactly at 180s or 50mm. And you do it three times, and you take the average of the three times.

This is oxygen index apparatus of experiment operation steps, small make up mainly from experiment before and after an interpretation for everyone to do, here small make up remind everyone's attention, at the time of calculating oxygen index should be average, accurate to one decimal places, computation formula is as follows: (OI) = O2 / (O2 + N2) * 100, among them, the volume percentage of oxygen index, gets the experimental value in oxygen index value of reference materials, it is concluded that the experimental results.

If you encounter any problem when operating the digital oxygen index tester, please contact us, and our after-sales engineer will help you solve it in the first time!

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