RU2001393C1 - Method for determining oxygen and/or temperature indices of materials - Google Patents

Description

In the absence of ignition, the ignition process was repeated. The samples themselves were made in the form of rectangular plates measuring 150 x 10x4 mm. The presence of sustained combustion of such samples was established upon the continuous burning of 500 mm of their length.

A change in the oxygen concentration in the mixture near the limiting values was carried out according to the readings of oxygen and nitrogen flow sensors with a step of at least 0.2% of the total mixture, the flow rate of which at the same time remained constant and equal to 177 cm.s at room temperature, which corresponds to the speed established by GOST flow in the reaction chamber equal to 340 mm-s.

The test results are presented in table. 1, where, for comparison, the oxygen index values of the same materials obtained by the known method are also shown.

In the table. 1 also shows the results of measurements of the duration of the ignition process in each of the methods gz.

The range of oxygen index values indicated in the table is due to the scatter of the results of repeated measurements on 3 samples.

A specific determination of the temperature index of the material using the proposed method was carried out on the installation, which included all of the above elements of the installation for determining the oxygen index and was additionally equipped with devices for heating and holding at a given temperature the oxygen-nitrogen medium in which the samples were tested. and six

temperature sensors located three inlet from the reaction chamber. At 5, the test temperature is defined as the average value of the readings of all sensors, provided that the spread of these readings does not exceed 10 ° C. The upper limit of heating is 350 ° C.

The flow rate of the oxygen-nitrogen medium, regardless of its temperature, was set equal to 4 cm / s. Samples of 150 x 13 x 1.5 mm in size were made from new materials synthesized based on polypropylene.

The test results are given in 5 table. 2.

At temperatures above 100 ° C, plasticization of polypropylene is observed. Therefore, the experimental temperature dependence of 0 values of the oxygen index was processed on a computer and thus extrapolated based on the known extrapolation models to a value of 8, which made it possible to determine the value of the temperature index, which turned out to be 220 ° C.

As can be seen from the data in table. 1, the difference in the values of the oxygen index measured by the proposed and known methods is in the range of 0.5-0.7 units, which is 0 times three times the value of the possible hardware error of such measurements.

(56) Fire and explosion hazard of substances and materials, nomenclature of indicators and 5 methods for their determination. GOST 12.1.044-84 (CMEA 1495-79), 1895.

UK patent No. 1356023, CL G01 N25 / 00.

Table 1

table 2

7 20013938

Formula and zobreteniy and its effects on the sample. METHOD FOR DETERMINING OXYGEN AND / OR DIFFERENT THEM. that, with the aim of expanding the TEMPERATURE INDEX of MATERIALS in the range and increasing the accuracy by igniting the sample with a fuel flame by standardizing the gas in a given flow5, the temperature of the igniting flame, the combustible oxygen-nitrogen medium, and establishing the gas are pre-mixed with air - the limits of sustainable burning of the sample by suction until a stoichiometric oxygen concentration is formed and in temperature or lean mixtures, and the flame is shielded in this stream under standard conditions, so as to prevent penetration ix including limiting the size of the outer U-gaseous medium in front go- Gigue flame zone and continuously-rhenium.