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Laboratory Fume Hood And Exhaust System

Aug 25, 2018

Laboratory Ventilation and Exhaust During the chemical experiment, various unpleasant, corrosive, toxic or explosive gases are often produced. If these harmful gases are not excluded from the outdoor, it will cause indoor air pollution, affecting the health and safety of the experimental personnel; affecting the accuracy and service life of the equipment, therefore, laboratory ventilation is an indispensable part of the laboratory design. In order for laboratory personnel to inhale or inhale some toxic, pathogenic or toxic chemicals and organisms, there should be good ventilation in the laboratory. To prevent some vapors, gases and particulates (smoke, soot, dust and aerosols) from being inhaled, the pollutants must be removed by means of a fume hood, hood and partial exhaust.

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<br><div></div>1080/5000Huàxué shíyàn shì de tōngfēng fāngshì yǒu liǎng zhǒng, jí júbù pái fēng hé quán shì tōngfēng. Júbù pái fēng shì zài yǒuhài wùzhí chǎnshēng hòu lìjí jiùjìn páichū, zhè zhǒng fāngshì néng yǐ jiào shǎo de fēngliàng pái zǒu dàliàng de yǒuhài wùzhí, néngliàng shěng ér xiàoguǒ hǎo, shì gǎishàn xiàn yǒu shíyàn shì tiáojiàn kěxíng hé jīngjì de fāngfǎ, yě kěnéng shì shìyìng xīn shíyàn shì tōngfēng jiànshè de zuì hǎo fāngshì. Duìyú yǒuxiē shíyàn bùnéng cǎiyòng júbù pái fēng, huò júbù pái fēng mǎnzú bùliǎo pái fēng yāoqiú shí, cǎiyòng quán shì tōngfēng.
Tōngfēng guì shì shíyàn shì zhōng zuì chángyòng de yī zhǒng júbù pái fēng shèbèi, tā dì xìngnéng hǎo huài zhǔyào qǔjué yú tōngguò tōngfēng guì kōngqì yídòng de sùdù. Yǐngxiǎng zhèngmiàn sùdù hé kōngqì yùndòng de yīnsù shì wōliú, guì de rùkǒu xíngzhuàng, rè zǎi liàng, jīxiè zuòyòng, pái fēng kǒng shèjì hé zǔ níng wù děng. Cǐwài, shàng yú tā de fánghuǒ nénglì, nài fǔshí xìng, shìfǒu biànyú qīngxǐ yǐjí wūrǎn wù jìnrù pái fēng xìtǒng qián shōují mǒu xiē wūrǎn wù de nénglì děng xìngnéng yǒuguān. Yībān rènwéi, shíyàn shì zhōng de tōngfēng guì yīng néng shìyìng yì rán de yètǐ hé qìtǐ, érqiě jiégòu cáiliào yìng jùyǒu jǐ fēnzhōng de nàihuǒ nénglì, yǐ bǎochí tōngfēng guì de wánzhěng hé jíshí jiāng huǒ fēng xī.
Tōngfēng guì de pái fēng xìtǒng kě fēn wéi jízhōng shì hé fēnsàn shì liǎng zhǒng. Jízhōng shì shì bǎ yī céng lóu miàn huò jǐ céng lóu miàn de de tōngfēng guì zǔchéng yīgè xìtǒng, huòzhě zhěnggè shíyàn lóu fēnchéng yī'èr gè xìtǒng. Tā de tèdiǎn shì tōngfēngjī shǎo, shèbèi tóuzī shěng, érqiě duì tōngfēng guì de shùliàng shāo yǒu zēng jiǎn, yǐjí wèizhì de biàngēng, dōu jùyǒu yīdìng de shìyìng xìng. Rán'ér yóuyú xìtǒng jiào dà, fēngliàng bùyì pínghéng, jǐnguǎn měi gè tōngfēng guìshang dōu zhuāng yǒu tiáojié fá, dàn shǐyòng bù fāngbiàn, bìngqiě yě bù róngyì dádào yùdìng de xiàoguǒ. Rúguǒ xìtǒng fēng guǎn sǔnhuài xūyào jiǎnxiū shí, nàme zhěnggè xìtǒng de tōngfēng guì jiù wúfǎ shǐyòng. Suǒyǐ, yuánlái cǎiyòng jízhōng shì xìtǒng de shíyàn shì, xiānhòu dōu gǎi wèi yòng fēnsàn shì xìtǒng.
Fēnsàn shì shì bǎ yīgè tōngfēng guì huò tóng fángjiān de jǐ gè tōngfēng guì zǔchéng yīgè pái fēng xìtǒng. Tā de tèdiǎn shì: Kě gēnjù tōngfēng guì de gōngzuò xūyào lái qǐ bì tōngfēng jī, xiānghù bù shòu gānrǎo, róngyì dádào yùdìng de xiàoguǒ, érqiě bǐ jízhōng shì jiéshěng néngyuán, yīnwèi jízhōng shì xìtǒng, zhǐyào yīgè tōngfēng guì zài shǐyòng, jiù dé kāidòng dàtōngfēng jī. Fēnsàn shì yóuyú xìtǒng xiǎo, pái fēngliàng yě xiǎo, zǔlì yě xiǎo, suǒyǐ tōngfēng jī de fēng liàng, fēng yā dōu bù dà, zào shēng yǔ zhèndòng xiāngyìng yě jiào xiǎo. Fēnsàn shì hái yǒu yīgè tèdiǎn, shì duì páichū bùtóng xìngzhì de yǒuhài qìtǐ yìyú chǔlǐ. Quēdiǎn shì tōngfēng jī de shùliàng duō, xìtǒng duō, rúguǒ tōngfēng jī jízhōng yú tōngfēng jīfáng nèi, nàme tóuzī jiù huì zēng dà, rúguǒ tōngfēng jī fēnsàn bùzhì, érqiě jiù dì ānzhuāng, suīrán tōngfēng jī de tóuzī zēngjiā, dàn fēng guǎn de tóuzī kě jiéshěng, zuìhòu zǒng tóuzī bù yīdìng zēng dà. Jiànyì shǐyòng fēnsàn shì. Zài huàfēn xìtǒng shí, tóng yīgè fángjiān nèi rú yǒu liǎng gè yǐshàng de tōngfēng guì, yīng huà wéi yīgè xìtǒng, bìmiǎn yīgè tōngfēng guì zài shǐyòng, qítā de tōngfēng guì chǎnshēng dàoliú, shǐ shìnèi shòudào wūrǎn. Tóngyàng, yīgè fángjiān nèi chúle yīgè pái fēng xìtǒng wài, bùyí zài zhuāngzhì qítā pái fēng shèbèi.
Pái fēng xìtǒng de tōngfēng jī, yībān dōu zhuāng zài wūdǐng shàng, huò dǐngcéng de tōngfēng jīfáng nèi, zhèyàng kěbù zhànyòng shǐyòng miànjī, érqiě shǐ shìnèi de pái fēng guǎndào chǔyú fù yā zhuàngtài, yǐmiǎn yǒuhài wùzhí yóuyú guǎndào de fǔshí huò sǔnhuài, yǐjí yóuyú guǎndào bù yánmì ér shènrù shìnèi, cǐwài, tōngfēng jī ānzhuāng zài wūdǐng shàng huò dǐngcéng de tōng fēng jīfáng nèi, jiǎnxiū fāngbiàn, yìyú xiāo shēng huò jiǎn zhèn.There are two types of ventilation in chemical laboratories, local exhaust and full room ventilation. Local exhaust is discharged immediately after the generation of harmful substances. This method can remove a large amount of harmful substances with less air volume, and the energy is saved and the effect is good. It is a feasible and economical method to improve the existing laboratory conditions, and may also It is the best way to adapt to the new laboratory ventilation construction. For some experiments, local exhaust should not be used, or local exhaust should not meet the requirements of exhaust ventilation.
The fume hood is the most commonly used local exhaust device in the laboratory, and its performance depends mainly on the speed of air movement through the fume hood.Factors affecting frontal speed and air movement are eddy currents, cabinet inlet shape, heat load, mechanical action, venting hole design, and condensate. In addition, it is related to his ability to fire, corrosion, ease of cleaning, and the ability to collect certain contaminants before they enter the exhaust system. It is generally believed that the fume hoods in the laboratory should be able to accommodate flammable liquids and gases, and that the structural materials should have a few minutes of fire resistance to keep the fume hood intact and in a timely manner.
The exhaust system of the fume hood can be divided into two types: centralized and decentralized. Centralized is a system of one or two floors of fume hoods, or the entire experimental building is divided into two systems. It is characterized by fewer ventilators, less equipment investment, and a slight increase in the number of fume hoods, as well as changes in location, have a certain degree of adaptability. However, due to the large system, the air volume is not easy to balance. Although each fume hood is equipped with a regulating valve, it is inconvenient to use and it is not easy to achieve the intended effect. If the system duct is damaged and needs to be repaired, the entire system's fume hood cannot be used. Therefore, laboratories that used centralized systems have been replaced with decentralized systems.
Decentralized is the integration of a fume hood or several fume hoods in the same room into an exhaust system. His characteristics are: the fan can be turned on and off according to the working needs of the fume hood, mutual interference, easy to achieve the desired effect, and more energy-saving than centralized, because the centralized system, as long as a fume hood is in use, Start the big fan. Due to the small size of the system, the air volume is small and the resistance is small. Therefore, the air volume and wind pressure of the fan are not large, and the noise and vibration are correspondingly small. Another feature of the decentralized type is that it is easy to treat harmful gases that discharge different properties. The disadvantage is that the number of ventilators is large and the system is many. If the ventilator is concentrated in the ventilator room, the investment will increase. If the ventilator is dispersed and installed on site, although the investment of the ventilator increases, the investment of the duct Can save, and finally the total investment does not necessarily increase.Decentralized is recommended. When dividing the system, if there are more than two fume hoods in the same room, it should be divided into one system to avoid one fume hood being used, and the other fume hoods to reverse flow, so that the indoors are polluted. Similarly, in addition to an exhaust system in a room, it is not appropriate to install other exhaust devices.
The ventilator of the exhaust system is generally installed on the roof or in the ventilator room on the top floor, so that the occupied area is not occupied, and the indoor exhaust duct is under negative pressure to avoid harmful substances due to corrosion or damage of the pipeline, and Because the pipeline is not tight and penetrates into the room, in addition, the ventilator is installed on the roof or in the ventilator room on the top floor, which is convenient for inspection and easy to eliminate or reduce vibration.