Hermetically-sealed formaldehyde extractor

Abstract

A hermetically-sealed formaldehyde extractor comprises: 1. an electric heating sleeve, 2. a round-bottom distilling flask, 3. No.1 sand core filter plate, 4. an extracting part, 5. a sintering sealed division board, 6. a condensing part, 7. a condensed water outlet, 8. a ground glass plug, 9. a pressure balancing tube, 10. a condensed water inlet, 11. a steam liquid outlet pipe, 12. an absorption liquid outlet, and 13. a distillation and siphon pipe. The operation method comprises the following steps: weighing 105 to 110 grams of a sample, putting the sample into the round-bottom distilling flask 2, adding 600 mL of toluene into the distilling flask, opening the ground glass plug 8 in the extractor, adding 300 mL of water extract liquid, covering the ground glass plug 8, starting the cooling circulation water, starting to heat, heating until the toluene reaches the boiling point, then carry out refluxing for 2 hours, in this period, cooling the evaporated mixed liquid of toluene and formaldehyde in the condensing part 6, subjecting the condensed liquid to go through the extracting part 4, then subjecting the extract residual liquid to go through the distillation and siphon pipe and reflux to the round-bottom distilling bottom 2, keeping on the continuous reflux of toluene, distilling for 2 hours, washing the extract liquid into a 1000 mL volumetric flask through the absorption liquid outlet 12, and finally diluting the extract liquid to 1000 mL for later detection.

Description

technical field [0001] The invention relates to a testing device, in particular to a fully-sealed formaldehyde extraction device. Background technique [0002] As we all know, at present, the main basis for the determination of formaldehyde in wood-based panels by perforation extraction at home and abroad is EN 120-1992 Determination of formaldehyde content in wood-based panels. The perforation extraction instrument mainly includes four parts: distillation bottle, extraction tube, and condenser tube And the triangular flask and straight tube anti-siphon ball for liquid seal. The instrument takes up a lot of space. A set of perforated extractors will occupy a set of fume hoods. The extraction tube is about 80 cm long. After connecting the condenser tube, distillation bottle and heating device, the height can reach about 200 cm. It cannot be placed in a general laboratory fume hood. use. According to the standard, the formaldehyde content of a board is the arithmetic mean of...

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Problems solved by technology

The instrument takes up a lot of space. A set of perforated extractors will occupy a set of fume hoods. The extraction tube is about 80 cm long. After connecting the condenser tube, distillation bottle and heating device, the height can reach about 200 cm. It cannot be placed in a general laboratory fume hood. use

According to the standard, the formaldehyde content of a board is the arithmetic mean of the formaldehyde emission of two test pieces in the same board, and a sample needs to be extracted at least twice, and once there is an unqualified sample, it is necessary to extract another sample that can represent the sample Two plates are re-inspected, that is, when an unqualified sample needs to be re-inspected, the three plates of the sample need to be fully extracted six times, the workload is heavy, and the detection cycle is long; there are many extraction instrument interfaces specified in EN 120-1992 , a set of devices has a total of six interfaces, the sealing is difficult, and it is easy to have air leakage, which will affect the test results; EN 120-1992 requires that the temperature of the water extract should not exceed 40°C, but there is no line in the instruments required by the standard. The effective temperature control measures cannot control the temperature of the extract, and it is easy to cause the extract to be heated by the refluxed toluene to exceed 40°C during the extraction process, which will affect the extraction effect and make the measured result low; adding and transferring the toluene solution If it is carried out in an open space, it is very easy to cause environmental pollution, and the requirements for the ventilation facilities of the experimental environment are relatively high. General laboratories cannot carry out the test of this project; the extraction tube is too high, and a large part of the distillate directly flows back into the distillation bottle, which cannot be completed. The entire extraction process affects the measurement results; the entire extraction device has a large heat loss, low extraction efficiency, and cannot accurately control the distillate flow rate

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