A safe and energy-saving perchloric acid fume hood

Abstract

The invention relates to a safe and energy-saving perchloric acid fume hood. The safe and energy-saving perchloric acid fume hood comprises a fume hood body, a variable air volume control system and an acid mist purification system, wherein the variable air volume control system comprises a variable air volume valve, an exhaust fan and an exhaust pipe; the acid mist purification system comprises a plurality of PP water distribution balls, nozzles, a PP upper water tank and a PP lower water tank; a plurality of water level probe control devices, a pH value adjustment metering pump and a corrosion-preventing pump are arranged on the PP lower water tank; the PP lower water tank is used for providing circulating spraying water for the nozzles through a circulating water pump and a circulating water pipe; the PP upper water tank is communicated with a PP lower water tank pipe; during use, acid mist gas flows upwards and water flows downwards to form counterflow exchange, so that the acid mist gas is in full contact with water mist, and lots of acid mist is dissolved in water to purify perchloric acid; when the pH value in the PP lower water tank is increased to a certain value, an alkaline reagent is automatically added into the PP lower water tank to realize neutral reaction, and then wastewater conformed with the discharge standards is discharged; after the wastewater is completely discharged, fresh water is injected into the PP lower water tank for continuous circuiting spraying use.

Description

technical field [0001] The invention relates to the field of laboratory equipment, in particular to a safe and energy-saving perchloric acid fume hood. Background technique [0002] The fume hood is the most important safety equipment in the modern laboratory. It uses the exhaust system to ensure sufficient negative pressure in the fume hood to ensure that the experimenters and the experimental environment are not polluted by chemical substances. The fume hood has a strict air volume control system. However, in addition to ensuring sufficient negative pressure safety factors in the fume hood for perchloric acid, there is another important risk factor that needs to be guaranteed, that is, crystals of perchloric acid will adhere to the inner wall of the fume hood during the experiment. and the inner wall of the exhaust duct. In many metal pretreatment experiments, perchloric acid HClO is often used 4 A chemical reaction occurs with alkali metals. This chemical reaction proce...

AI Technical Summary

Problems solved by technology

In many metal pretreatment experiments, perchloric acid HClO is often used 4 A chemical reaction occurs with alkali metals. This chemical reaction process will produce a large amount of acid mist. Perchloric acid diffuses to the deflector of the fume hood and the inner wall of the exhaust duct by the wind of the fume hood. Crystallization, after a period of accumulation, a perchloric acid crystallization layer will be formed inside the fume hood and the exhaust duct. When the crystallization layer reaches a certain thickness, the crystallization layer will burn and explode when it touches water or vibrates or hits, and the explosion intensity is very high. Big, in recent years, there have been casualties in this area. In order to eliminate this hidden danger, the experimenters carried out irregular manual water spray cleaning in the ventilation ducts. Although the experimenters made a lot of efforts, there were many corners inside the fume hood. The inside of irregular air ducts such as elbow tees of exhaust ducts cannot be cleaned in place. Perchloric acid crystal layers are prone to form in these places, and there are still great safety hazards. Moreover, this cleaning method that treats the symptoms but not the root causes wastes water resources. , labor-intensive, water leakage and other shortcomings

As attached to the manual Figure 7 , 8 As shown, the exhaust gas of the traditional fume hood is concentrated on the roof for treatment and discharge. The exhaust gas containing strong acid will first corrode the exhaust pipe and exhaust equipment, or some acid liquid will precipitate or stick to the exhaust pipe. After a long time, there will be waste liquid. Return to the experimental laboratory; and this kind of system consumes a lot of energy. Usually, the air volume range of the exhaust system is changed, and the amount of purified water is fixed. When the system only has part of the fume hood or even only one ventilation When the cabinet is in use, this external purification system must be fully turned on, resulting in waste

[0003] The medium of the fume hood is air and water. How to solve the problem of sufficient contact between air and water is the key technology of the perchloric acid fume hood. The airflow organization inside the fume hood is constantly changing. It is not realistic to make an air model. Continuously summarize the data, and many components and equipment are subject to relevant suppliers. We will design a water separation ball model with higher water separation efficiency, and the hydraulic characteristics of the circulating water system, so that the pump manufacturer can customize this type of water pump. Up and down Seat water tanks are mostly made of PP material. There is no such product on the market, so they can only be customized by making molds. All of these have brought technical difficulties to the development and production of perchloric acid fume hoods. We need to combine theory with practice, constantly sum up experience, and finally Developed a standardized perchloric acid fume hood with high efficiency, low energy consumption and low cost

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