Temperature control method and device for enrichment pipe

Abstract

The invention discloses a temperature control method and a temperature control device for an enrichment tube. In the method, when the temperature of the enrichment tube needs to be obtained, firstly, the platinum wire used as a heating element does not generate heat; The temperature value on the platinum wire serving as the temperature measuring element; then use the proportional integral differential algorithm to calculate the obtained temperature value on the platinum wire serving as the temperature measuring element and the temperature required by the enrichment tube to obtain the output control amount, when the output control When the output control value is less than or equal to 0, the platinum wire serving as the heating element will not generate heat until the next temperature control cycle begins; when the output control value is greater than 0, determine the heating power that needs to be loaded on the platinum wire as the heating element so The platinum wire that acts as a heating element heats the enrichment tube at this heating power until the next temperature control cycle begins; the advantage is that the platinum wire acts as both a temperature measuring element and a heating element, so there will be no Changing the temperature field near the temperature measurement point effectively improves the measurement accuracy.

Description

technical field [0001] The invention relates to an enrichment tube temperature control technology, in particular to an enrichment tube temperature control method and a temperature control device. Background technique [0002] When the concentration of the sample to be tested (such as indoor gas, etc.) is very low, the sample to be tested cannot be directly sent to the gas chromatograph with limited sensitivity for analysis, but the sample to be tested needs to be passed into the enrichment tube of the gas chromatograph first , and then use the enrichment tube to enrich the sample to be tested. After enriching to a certain concentration, the temperature of the enrichment tube is quickly raised to make the tested sample in the enrichment tube desorb quickly and enter the chromatographic column of the gas chromatograph. separate. However, due to the fast heating rate, whether the real-time value of the temperature can be accurately obtained when the enrichment tube is heated i...

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Problems solved by technology

[0003] 1) The temperature of the measurement point is lower than the actual temperature: due to the small volume of the enrichment tube, its pipe diameter is the same order of magnitude as the diameter of the temperature sensor that can withstand the conventional target temperature of thermal desorption of 300°C, so the introduction of the temperature sensor will affect the temperature of the measurement point. The nearby temperature field has a great influence, making the temperature of the measurement point lower than that of other positions in the enrichment tube, which will bring errors to the measurement, and the uneven temperature of the enrichment tube will affect the repeatability of the instrument

[0004] 2) The temperature of the measuring point is easily affected by the temperature of the heating wire: in order to correctly measure the temperature of the enrichment tube instead of the heating wire, it is required to keep a certain distance between the thermal element at the head of the temperature sensor and the heating wire, and this will also cause enrichment The problem of uneven header temperature

[0006] 4) The temperature sensor is difficult to install: due to the small volume of the enrichment tube, it is impossible to open a mounting hole for the temperature sensor, making it difficult to fix the temperature sensor conveniently

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