Oxygen index tester

Abstract

The invention discloses an oxygen index tester which comprises an oxygen channel, a nitrogen channel, a controller module and a human-machine interface module, wherein the oxygen channel and the nitrogen channel are both connected with a gas mixing cylinder, and then connected with a combustion cylinder through a temperature controller and an oxygen sensor; the oxygen channel and the nitrogen channel are both provided with a flow switch valve and a quality flow controller; a temperature sensor is arranged in the temperature controller; the controller module is connected with a control input end of the temperature controller; the detection values of the temperature sensor in the temperature controller and the oxygen sensor are collected at the same time, and the detection values are output to the human-machine interface module; the human-machine interface module comprises a display part, an input part and a control part, wherein the input part inputs a control quantity related parameter value to the control part, and the control part respectively calculates the control quantity of oxygen and nitrogen according to the related parameter value and then outputs the control quantity to the controller module; and the controller module controls the quality flow controller according to the received control quantity so as to achieve the aim of automatically adjusting and controlling as well as improving the test precision.

Description

technical field [0001] The invention relates to the technical field of measuring the oxygen index required for material combustion, in particular to an oxygen index measuring instrument. Background technique [0002] Oxygen index meters can determine the oxygen index of a variety of materials such as plastics, rubber, textile fabrics, wood, foam and other polymeric materials. Oxygen index (LOI) refers to the minimum oxygen concentration required for a material to burn flamingly in an oxygen-nitrogen mixed flow under specified conditions. It is expressed as the numerical value of the volume percentage of oxygen. According to the national standard Gβ / T2406.2-2009 "Determination of Combustion Behavior of Plastics by Oxygen Index Method", the test principle is: a sample of a specified size is vertically supported in a transparent combustion cylinder of a specified size, and there is a certain concentration in it from bottom to top Use the igniter to ignite the upper end of the...

AI Technical Summary

Problems solved by technology

[0010] The shortcomings of these two test methods are: in the first method, the oxygen concentration of the mixed gas is determined by adjusting the flow rate of oxygen and nitrogen, and the purity of oxygen and nitrogen is ignored. This calculation method assumes that the initial oxygen and nitrogen are pure oxygen and pure nitrogen.

In the second method, the flow rate of oxygen and nitrogen is manually adjusted, the control accuracy is low, and both hands are required to operate at the same time. At the same time, the human eye also needs to observe the oxygen concentration value and flow value, which is difficult, the whole process is complicated to operate, labor-intensive, and the waste of gas and samples is serious.

At the same time, these two methods also have common shortcomings: the influence of the temperature of the mixed gas on the test results is ignored, and the temperature of the mixed gas cannot be stabilized within the range specified by the national standard

Moreover, the experimental process requires experienced operators to operate, and the equipment cannot guide users to conduct experiments automatically, and the calculation of later numerical values ​​is complicated and requires manual calculations, which requires high requirements for operators.

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