Structure of a dust-free spray booth for furniture
Principle and structure of the dust-free spray booth designed and manufactured by Jinan Tiansheng Environmental Protection: The entire structure is assembled. The body uses a plug-in type insulation wall panel with good sealing and insulation performance. The aluminum alloy clad door has an observation window in the center, allowing for real-time observation of the interior; a work door is installed on the side of the body for easy access by personnel; filter cotton and low-noise, high-volume fans are selected to ensure perfect spray painting results.
During spraying, the outside air is pre-filtered through the air intake, then sent into the paint room's static pressure chamber by the blower. After secondary filtration through the top filter cotton, it flows evenly into the paint room's working space. The airflow forms an air curtain around the workpiece from top to bottom. At this time, the air velocity inside the paint room is >0.3m/s, and the paint mist produced by spraying will not stay in the operator's breathing zone but will quickly descend with the airflow. After bottom water filtration, the airflow is discharged at high altitude through the exhaust duct, and the paint waste gas can also be discharged through environmental protection equipment for waste gas treatment.
Furniture spray booths mainly refer to places where the surface of objects is sprayed with paint and the paint is allowed to dry. Different objects, such as furniture and sheet metal, have their surfaces coated with color or gloss.
Spray Booth Classification by Airflow Direction
Crossflow Spray Booth
Airflow moves from one end of the booth to the other. This type is low cost and easy to install. The downside is that the mist moves along the sides of the object, and the mist cannot be removed from around the operator's face, resulting in a less-than-ideal work environment.
Side Down-Draft Spray Booth
Air enters the spray booth through the ceiling filter and is exhausted from the side walls near the floor. This is a mid-range priced spray booth. Because the mist is away from the object itself and the mist can be removed from around the operator, both the spray effect and the work environment are quite ideal.
Full Down-Draft Spray Booth
Represents the most advanced technology today. Air enters from the ceiling and is exhausted to the outside through a pit or basement. This exhaust method provides a cleaner spraying process and a safer working environment. However, it is expensive and takes up a lot of space.

Classification by Treatment Method
It can be divided into two main categories: dry spray booth and wet spray booth (water treatment).
Dry treatment is most commonly used in normal spray booths, so the filter system (mainly referring to primary and secondary filter cotton, etc.) needs to be regularly inspected and replaced. Otherwise, it will affect the paint quality at best, and may cause a fire at worst. With the further development of science and technology, the methods for handling excess paint mist are becoming more and more advanced. Many high-end cars use water treatment spray booths, dissolving excess paint mist in water, making significant progress in paint mist treatment.
Three Key Aspects of a Draft Spray Booth
(1) Ventilation - The key to the operation of a draft spray booth
(2) Filtration - Filtering small particles from the air
(3) Exhaust - Exhausting waste air and introducing fresh air
(4) Odor Removal - Effectively removing odors from the spray booth
Principle
Air (outdoor air) - spray booth door filter cloth - spray table - using spray equipment for spray painting - exhaust fan (exhausting the paint mist produced). This spray booth still has weaknesses:
(1) The filter cloth is easily scratched, and dust easily enters.
(2) Easily allows unclean outdoor air to enter.
(3) Unenvironmental, wasteful of paint.
(4) Requires frequent cleaning and regular removal of dirt from the filter cloth. A new type of spray booth has emerged - the full-pressure spray booth, which has been widely used in China's furniture industry. The basic principle of the full-pressure type is the same as that of the draft spray booth, but it utilizes the directionality of pressure, using pressure to vertically spray from top to bottom, making spraying more precise. In addition, in terms of hardware, there is a main room, which replaces the filter cloth with "multi-layer filter cotton", resulting in high air cleanliness; infrared baking lamps are used to save drying time; when discharging excess paint mist, water curtains are used for better environmental protection, and environmental protection equipment can also be added to the spray booth. Commonly used environmental protection equipment on the market includes catalytic combustion equipment and secondary activated carbon adsorption equipment, which greatly improves the efficiency of meeting current environmental protection requirements for paint waste gas from spray booths.

Working Principle of Furniture Spray Booth
During spraying, the outside air is pre-filtered through the air intake, then sent into the paint room's static pressure chamber by the blower. After secondary filtration through the top filter cotton, it flows evenly into the paint room's working space. The airflow forms an air curtain around the workpiece from top to bottom. At this time, the air velocity inside the paint room is >0.3m/s, and the paint mist produced by spraying will quickly descend with the airflow. After bottom water filtration, the airflow is discharged at high altitude through the exhaust duct.
Paint Booth Air Purification System
The filter system uses two layers of filtration and catalytic combustion equipment or secondary activated carbon adsorption equipment. The coarse filter layer effectively captures dust particles larger than 10um in diameter, and the precision-grade high-efficiency filter layer has a multi-layer structure that can effectively capture dust particles larger than 4um in diameter. The entire filter system has a large dust holding capacity, low resistance, long life, and a filtration efficiency of over 98%, meeting emission standards.
Air Circulation System
The air circulation system consists of a complete set of units. The unit's matching fan is determined by the size of the spray booth, ensuring an air velocity of >0.3m/s, thus ensuring rapid air circulation in the room, no paint mist residue, and ensuring the health of operators and the spray painting effect. The fan uses a spray and baking paint booth-specific air conditioner fan produced using Siemens technology, with a compact structure, low power consumption, and stable performance.
Paint Mist Treatment System
Paint mist treatment uses water/dry filtration, with low operating costs, ideal paint mist adsorption, and good results. Indoor noise complies with GBJ87-85 "Industrial Enterprise Noise Control Design Specifications", not exceeding 85 decibels. The current development status and working structural principle in China
Domestic low-to-mid-range prices range from 22,000 to 60,000, while high-end prices range from 60,000 to 150,000. There is a wide variety of products. Main types in circulation include: outdoor rainproof paint booths, fuel-fired high-temperature paint booths, teaching spray paint booths, large passage-type paint booths, environmentally friendly paint booths, infrared paint booths, and standard paint booths, etc., each with different functions; general paint booths adopt a prefabricated structure, the body uses a plug-in type heat-insulating spray-painted wall panel, with good sealing and insulation performance, the side of the body is equipped with a work door for easy access for staff, aluminum alloy edged doors, and an observation window in the center of the door to observe the interior dynamics at any time. The auxiliary equipment in the paint booth is also emerging, and those with higher usage rates include: fans, burners, lighting, bottom plates, filter cotton, control boxes, generation rooms, paint lamps, high-efficiency heat exchangers, etc. Of course, the specific configuration and model depend on the overall planning of the automotive service institution.
Workpiece Spray Painting Provided
(1) A clean working environment;
(2) Thorough collection of paint mist.
The configuration of spray paint booths can vary depending on the size, shape, weight, and production schedule of the workpiece: there are open and closed types; continuous and intermittent types; workpiece self-rotation or fixed types; single-sided and double-sided spraying types. In recent years, oil curtain spray booths and under-spray paint booths have also been developed. The structure should include: air supply and filtration system, workpiece hanging (conveying, self-rotation) device, water curtain system, water washing system, exhaust system, water tank, lighting device, and chamber body.

Precautions
(1) Shellac cannot be used as a sealing primer for the PE series, otherwise it will affect the adhesion and heat resistance of the primer.
(2) The amount of blue water, white water, and thinner should be adjusted according to temperature, humidity, and seasonal requirements. If the ambient temperature is low and the construction requirements are fast, the amount of blue water and white water can be appropriately increased, and vice versa. When the humidity is too high and the temperature change is not large, increasing the amount of blue water has a significant effect.
(3) The amount of blue water and white water added is also limited. If too little is added, the paint film will not be sufficiently cross-linked, hardening will be slow, grinding will be difficult, and the overall performance will be poor. If too much is added, the cross-linking of the paint film will be accelerated, the usable period of the mixed paint will be short, the spray gun will be easily blocked, and cracks are likely to appear after film formation.
(4) The addition of thinner should be adjusted according to different important construction conditions to achieve the ideal spraying effect.
(5) During continuous construction, the spray gun, spray pot, and pipes should be frequently cleaned with thinner to remove old paint and re-mix the paint for use. After construction, the entire set of equipment must be thoroughly cleaned to ensure that the equipment can be used normally for a long time.
(6) When using PE series paints, blue water and white water cannot be mixed directly, otherwise a strong explosion and fire will occur. They must be mixed separately into the paint according to the regulations and stirred evenly before being mixed together for use.
(7) The mixed paint should be used up within 15 minutes at normal temperature to avoid waste or clogging of equipment.