How does the clean air ductless fume hood work?

Product principle

  The clean air fume hood does not require an external pipe, and the top comes with a fan and a filter. When the switch is turned on, the fan operates to create a negative pressure inside the cabinet to ensure that the chemical does not overflow. The wind direction of the main body is from bottom to top, so that the air in the cabinet is filtered through the filter, and the clean air is discharged from the top air outlet. On the one hand, it purifies the chemicals volatilized in the cabinet, and on the other hand, the air in the laboratory enters the cabinet, and the air in the laboratory can also be purified. Installation and commissioning is simple and convenient, energy saving and environmental protection, does not consume air conditioning, purifies the air in the laboratory, and protects the health of personnel.

Schematic

Technical advantages
1. No pollution to the environment
The activated carbon and auxiliary materials of the adsorbent material are derived from nature, and after being adsorbed by chemical chemicals, they are returned to nature after being harmlessly treated by a professional chemical waste treatment company.
2 , energy saving
The clean air after treatment by the ductless fume hood returns to the room, and the indoor air-conditioning wind will not be taken outside, which can save more than 90% of the air-conditioning loss.
And the ductless fume hood fan requires less power than the tubular power.
3 , easy to move
The ductless fume hood can be moved freely without an external pipe. Can be equipped with a roller cart.
4 , LED lighting
1 powerful power saving
The power 5w is equivalent to a fluorescent lamp of about 25w , and no heat is generated, which will not affect the experimental environment temperature.
2 long service life
Life of up to 100,000 hours, do not have to consider changing the lamp.
3 protect eyesight
LED lights are close to natural light, absolutely no flash, green and environmentally friendly.
4 protect the human body
No mercury harmful gases, no UV rays, infrared rays and heat radiation.
5 , electronic surface wind speed detection
Online display surface wind speed, high sensitivity probe for accurate measurement.
6 , the temperature display inside the cabinet
The temperature inside the cabinet is accurately displayed online.

Type of filter

Second, the performance parameters

Third, the use of clean air type ductless fume hood

It can effectively adsorb chemical gases, and there are many precautions when using a ductless fume hood.
1. Reduce scratches on the acrylic sheet.
2. When there is no experimental operation, the fume hood cannot be placed with chemical reagents. Always store the reagents in the medicine cabinet.
3 , always pay attention to whether the filter is saturated, such as saturation, contact the manufacturer for filter replacement, or the filter will lose its protection once it is saturated and not replaced in time.
4 , do not pile up debris in the fume hood, so as not to cause uneven airflow and not reach the proper surface wind speed, resulting in decreased adsorption efficiency.
5. Do not move the fume hood when using the fume hood. Do not probe the head into the fume hood for experiment.
6. After the end of the experiment, the fume hood should be kept running for a period of time to ensure that the residual gas in the cabinet is completely absorbed by the filter.

Fourth, the control part of Huafeng products

Huafeng online detection system - patented technology

1 , What is online monitoring system?
Huafeng Company's pipeline-free clean air fume hood and medicine cabinet come with an on-line monitoring system that can monitor the TVOC value of the filter outlet and display it on the LED screen, while monitoring the TVOC value in the chemical laboratory and displaying it in the LED. On the screen. This system allows users to know the saturation of the filter of the clean gas product they use, as well as to understand the air quality in the laboratory, to ensure the safety of users and to prevent unknown dangers and hidden dangers.

2 , background

Imported from Japan electrochemical probe of high sensitivity, combined with a chemical laboratories where complex software design, after numerous tests, when acetone as a reference substance, consistent with the PID data, an error of less than 5%.

A, a gas sensor sensitive material is a metal oxide, the most representative of SnO2, which is heated to a high temperature in air, the oxygen is adsorbed on a negatively charged surface of the belt, and then the surface of the crystal and the electron donor is Transferring to the adsorbed oxygen results in a positive charge in a space charge layer. This surface potential creates a barrier that blocks electron flow.
B. Inside the sensor, current passes through the bonding sites (grain boundaries) of the SnO2 crystallites. At the grain boundary, the adsorbed oxygen forms a barrier to prevent the carriers from moving freely, and the sensor's electricity is due to this barrier. When a reducing gas occurs, the surface concentration of the negatively charged oxygen decreases, resulting in a decrease in the barrier of the grain boundary. Thereby reducing the resistance of the sensor.

TVOC : Total   Votatile Organic Compound

It refers to a general term for various chemical organic compounds which can be volatilized into a gas at normal temperature, and the main components thereof are alkane, aromatic hydrocarbon, alkene, halogen, ester, aldehyde and the like. Irritating to the eyes, respiratory system, harming the liver, kidneys, brain and nervous system. The laboratory TVOC is very complex and usually contains many traces of chemicals that cannot be detected by existing detection methods.

5 , Alarm value setting

Huafeng Technology's online monitoring system uses dual probes, one probe to monitor the laboratory environment and the other probe to monitor filter saturation. OSHA ( American Occupational Safety and Health Association ) , ACGIH ( US Conference of Governmental Industrial Hygienists ) stipulates a TLV value of 300 ppm for acetone . For the saturation point setting of the filter, Huafeng Technology uses 1% TLV , or 3 ppm . For the laboratory environment, the recommended value is 3ppm, and the user can set it according to his actual situation and requirements.

6 , Huafeng product safety performance

•     The Huafeng product standard prepares a two-layer molecular filter, and the filter saturation monitoring probe is placed between the two-layer molecular filters.

•       When the on-line monitoring device detects that the filter is saturated and emits an audible and visual alarm, the trace amount of chemical gas will be filtered by the second layer filter, so the gas coming out of the product outlet is chemical-free.

•       When the first layer of filter is saturated, Huafeng Technology's second layer filter can continue to be used, and the newly replaced filter can be placed on the second floor, so the customer only needs to replace one filter at a time.

•     Huafeng Technology has developed a fully automatic calibration instrument with independent intellectual property rights. It uses PID as the benchmarking instrument and acetone is the calibration chemical. It performs point-to-point calibration with an error of less than 5% and good repeatability.

•       For the online monitoring system sold, in principle, it will be verified once every two years. The Huafeng technical engineer will replace the probe to be verified and issue a verification report.

•        Conditional customers can also use acetone as a volatile gas, using a gas chromatograph, PID for comparison.

8 , monitoring system stability

•     The probe supplier is a globally renowned brand.

•     The figure below shows the long-term stability data of the probe provided by the manufacturer.

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