Types of filters for spray booths. We organize indoor air purification

Sooner or later, every car needs an update paint coating. We are talking about 100 - 150 thousand km in the case of a domestic vehicle and 300 - 400 thousand km if the car is imported, not Chinese origin. You don’t have many options - use the services of a company service or garage technicians, or do everything yourself by building a paint booth. Even if you take into account the cost of renting equipment, a do-it-yourself paint booth will cost an order of magnitude cheaper than the services of painters.

Requirements for a spray booth

If a paint booth is installed in a garage, the room must meet the following requirements.

Mandatory insulation of walls and refusal to use flammable materials.
Achieving ultimate tightness.
A three-meter wall should be covered with a matte film to attract and retain dust particles. The resource of such a surface will be enough to paint 10 or more cars. Additionally, do not forget to treat the matte powder coating with a fire-retardant layer.
Two doors will ensure compliance fire safety. Tightness and ease of opening are the main requirements for these elements of the room.
The floor must be designed so that air flows freely. A coating in the form of a multilayer lattice will cope with this task, which will ensure optimal inflow and removal of air masses.
If the finished floor is metal, it should be installed 40 cm higher than similar surfaces in adjacent rooms. The bridge will soften the difference in floor surfaces.
Unimpeded entry into the box and optimal air exchange can be achieved using a concrete floor, the base of which will be on the same level as the adjacent rooms.
When settling in ventilation system pay attention to quality fastening elements. If the air intake passages become clogged, vapors from paint solutions will accumulate imperceptibly, which will lead to an explosion or local fire.
Be sure to consult with a specialist before carrying out construction work. It is also important to learn the principles of safe painting work.

What is it and how to produce it? You can find out about this from detailed material our specialist.

Interested in how to do it? Read about this in an interesting and informative article by our expert.

A DIY paint booth in the garage requires careful arrangement of a filter system with an exhaust pipe.

With a single-motor spray booth, the filter roll surface is laid around the perimeter of the entire ceiling. Removable pocket filters fixed in front of the ventilation system will ensure the retention of large debris.
If the room has two engines, you need to take care of an additional filter in the floor. To install the structure, you can choose a metal deck or an air duct system. Since the device takes on a significant load by lowering the paint spray mist down and drawing it out through the holes, the filter components used must be designed for rough cleaning. Alternatively, you can install a cassette grid fine cleaning in front of the device.

Sheathing and flooring

Also, a do-it-yourself paint booth for cars is made taking into account the requirements for floor arrangement. It is necessary to make trenches in finished floor and cover with a metal grid to raise its level by at least 15 cm. The ground cavity will become the place to install the ventilation motor.

If there is no suitable flooring in the room, you have two options.

If the flooring is solid, you can dig a rectangular hole with a recess a meter or two in size. If it is impossible to implement this stage, it is allowed to lay a second floor with an indentation of 20 cm. The hood for painting in the garage is installed in this space. It is also necessary to provide for the removal of air masses outside the paint box.
If inspection hole is already present, all that remains is to use a metal reinforcement grid to cover the recess. The boards must be laid under the sheathing in the form of wedges, and an acute angle must be formed at the garage entrance. The air duct pipe goes out from the underground cavity, and they will serve as bottom ventilation in the room.

Lighting organization

Technically correct lighting in the paint booth allows you to easily eliminate flaws in fresh paint and notice dust particles in the air. The best option fluorescent lamps will become visible to the human eye, which will ensure stable productivity of the work performed. Technological rules require illumination of 600 - 1000 lux. Fluorescent lamps It should be installed in two rows along the ceiling-wall perimeter. If it is impossible to achieve this option electrification can be limited to ceiling lighting.

Portable lighting is usually used when painting the lower elements of a vehicle.

Heating system

Requirements temperature standards must be taken into account, whether it is arranging a homemade professional or budget spray booth. Failure to comply with this category of requirements not only leads to a decrease in the quality of the paint coating, but also increases the risk of deterioration in the employee’s health:

local heating and electric heating elements enough in winter;
installing a heat gun will allow you to warm up the interior space and key ceiling points;
if large-scale operation is not expected, it is not economically feasible to buy a heat generator, since it will not pay for itself.

Consider the level of workload of the paint box when choosing a drying method, which is a mandatory step after applying paint to the surface of a car.

If a single painting is intended, you can give preference to air drying. Such a procedure will be quite long, and this factor acts as the main disadvantage.
If the paint booth is set up for commercial purposes, infrared equipment will become more smart choice, since complete drying can be achieved much earlier. Among the key advantages of infrared drying, it is worth highlighting the ability to dry any primer or putty, which becomes necessary during a full reconstruction vehicle. Electricity consumption is economical.

Often for interior decoration It is customary to choose a paint box covering with metal or plastic corrugated sheeting. Such a surface is easy to process; moreover, accumulated dust will be immediately noticeable on light-colored walls. Ideally, the color of the coating should be matte white. Decorative elements are allowed in this case; it is not necessary to adhere to the standard finish:

Cement-sand plaster is suitable for wall decoration small garage, reorganized into a painting booth. In this case, you should first moisten the surface with a spray bottle. The plaster will act like a sponge and will bind dust with water, which will ensure the cleanliness of the walls.
OSB boards or metal will contribute to the accumulation of dust, which can only be fully removed with a vacuum cleaner.
Plastic panels, in turn, accumulate 10 times more dust than wooden and metal surfaces.

Having calculated the ventilation in the allocated area Painting works indoors, the designer receives a static picture that gives a good approximation only in the first days of work. Filters tend to become clogged, disrupting circulation and reducing the efficiency of supply and exhaust fans. Therefore, the placement of ceiling and floor mats should allow for quick replacement, and the filtration system should allow for step-by-step particle screening.

Air from the street and air coming from spray booth, have different character pollution. Accordingly effective cleaning assumes different types filter materials at each screening stage. By functional characteristics There are three types of roll materials:

Coarse filter – installed externally, designed to separate large particles from the air.
Fine cleaning – protecting the room from dust, installed directly on the ceiling of the painting room.
Floor-standing – protection of the environment, as well as exhaust fan elements from waste associated with painting work.

According to European standards (EN 779 method), coarse cleaning can be considered the separation of particles up to 10 microns in size from the air flow (EU1 - EU4). Fine cleaning involves filtering particles up to 1 micron in size (EU5 – EU9). However, depending on how dust and material are separated, spray booth filters can last anywhere from a few months to a year. Filter elements are replaced at professional stations once every 8-12 months, but usually station owners do not skimp on expensive materials.

Large particles are separated using a conventional polypropylene mesh or a combination thereof. With internal filtration the situation is more complicated. Some craftsmen prefer to make do with a self-made non-woven filter, but it gets dirty very quickly, so the savings in this case are highly questionable. When purchasing a ceiling cleaner, you should pay attention to the following parameters:

Cleaning class (index EU or F).
Average holding capacity (indicated as a percentage for an air flow of 3400 m³/h).
The final and initial pressure difference created by the material (in Pascals).
Fire resistance.
Dust holding capacity.

A good filter material (dry cleaning), before the pressure drops to 80 Pa, is capable of retaining up to 0.3-0.5 kg of contaminants per 1 m². This result shows the most common material for filtering indoor air - polyester fibers. They are bonded to each other by heating, and the sides of the roll are strengthened reinforced mesh(sometimes the roll is stitched with mesh), the quality of which also affects the price. Anti-pilling impregnation, to which dust simply sticks, can increase the filtration efficiency.

Floor filters

Filtration paint and varnish materials contained in the air leaving the chamber requires other approaches, and the most effective of them is water curtain. Harmful substances from paint mist are easily retained by water, but designing a chamber with a built-in water curtain is quite problematic and costly, so a hydraulic filter for the spray booth is often used in paint booths. As the name implies, the active element of this design is a box with water. Most often it is a horizontal box made of polypropylene (sometimes made of galvanized steel), installed outside, on the ventilation outlet pipes.

Substances dissolved in water must be removed, otherwise their accumulation will lead to the fact that such a filter will not be cleaned or will simply become clogged with paint particles. To do this, a special substance – a coagulant – is added to the circulation system of the spray booth’s hydraulic filter. Chemical reaction with it leads to the precipitation of dissolved contaminants into sediment, which is removed mechanically.

Two other filtration methods are pocket filter systems (FYAC) and cardboard filter systems. The advantage of the former is their compactness and the ability to pass a large volume of air per m². Cardboard systems are an artificial labyrinth made of corrugated cardboard. The structure of the cardboard is such that the flow passing through it forms small vortices, from which heavy paint particles fly out by inertia and stick to the walls of the pockets (due to the principle of operation, such filtration is sometimes called inertial). The cardboard system is inexpensive (3-4 thousand for a roll of 10 m²), but often requires replacement. For comparison, a floor-mounted fiberglass filter, usually installed in a concrete chamber pit, costs approximately 1-2 thousand rubles per m².

Dry spray booth Thanks to the design and calculated technical proportions and parameters, it maximally removes excess paint mist and polluted air from the spray area, cleaning it.

It is very important to choose equipment with correct placement fan and power, because if:

The fan is weak - the suction power is insufficient, solvent vapors remain in the air and the paint settles on the floor and walls;

The fan is too strong - paint is removed that has not yet reached the product.

The noise load and the amount of power consumed by the equipment are also IMPORTANT.

Operating principle of a dry filtration spray booth:

1. Remove paint particles and dust from the spray area.

2. Removing the paint aerosol and eliminating the possibility of its spreading into surrounding areas.

3. Provision necessary conditions to create high quality coatings.

4. The removed air is cleaned of mechanical paint particles (remaining in the filters) and released into the atmosphere.

How is air filtered in dry spray booths?

The polluted air flow created by a fan (installed on the roof or diagonally), with paint particles, moves by inertia into the chamber opening where one or two filters are installed.

Filters are:

1. in rolls

The most popular is inertial action. Particles of paint, hitting the inner wall of the filter several times, settle, and the air continues to move by inertia. High filter holding capacity allows you to work without sweating the air suction speed. So in a dry painting booth 2 meters long, the suction area is 3.6 sq.m of surface (2 pieces of 2 meter rolls), the volume of paint retained is about 15 kg/sq.m. That is, it is capable of holding 54 kg of paint waste.

– used as the only filter level. Basically, preference is given in car cameras (specifics of placement). Provides the necessary degree of cleaning, however, when filling, the air flow rate decreases.

Air, cleared of mechanical paint particles, is released through ventilation into the atmosphere.

How long do filters last in a dry spray booth?

The question directly depends on many factors.

1. How much paint, varnishes, primers, etc. sprayed per day?

2. What kind of spray guns are used? (Which spray system?)

3. What products are painted?

4. How are cabins cleaned and filters replaced?

If you have a 2 meter dry paint booth, and you spray 20 liters per day (excluding solvent!!!), using a Chinese spray gun (with a traditional spray system, material transfer coefficient 40-45%), then (20 liters x 40 % = 8 liters per fog!), then taking into account the holding capacity of the filter is 15 kg/sq.m. (cabin suction area 3.6 sq.m.) – 1 filter replacement will last for – 7 days.

And one roll for 1 month!

What length should I choose for a dry spray booth?

We need to decide on maximum size products to be painted and similar or with a small margin, select the size. That is, if the product is 2.7 m, the cabin is 3 meters, if it is 1.8, then 2 meters. It also depends on how many painters will work in one booth.

What depth should I choose for a dry spray booth?

The depth of the cabin depends on the allocated room for painting; if it is planned that the painter will be inside the cabin, then you need to start from the size of the product. If the room is allocated 4 meters, and the cabin will be installed 3 meters, it is generally advisable to use a cabin with minimal side walls. Walls are also needed if there are two different painting stations nearby, to avoid problems with cross-pollination.

Scheme of a dry spray booth.

In diagram L1 - the depth of the spray booth ( working area)

Why do you need a dry spray booth? Can you work without it? We threw out the filters, we work like this!

Using open ventilation, without a cleaning system, violates all fire and sanitary safety requirements. The level of solvents and paint in the room is constantly accumulating. A stream of contaminated air, without first removing the paint, is released into the atmosphere through ventilation and settles on the surface around your building. In addition, there is a process of constant paint sticking to the air duct and fan. Any spark can lead to irreversible consequences! It is impossible to determine how long you can work in such conditions, it could be a month or a year or two, and when the day comes that will not allow you to change anything!

What is the working height of the spray booth (cabin)?

The cabin height is the entire height including the fan and roof. The working height is the suction area. The height of a standard cardboard filter is 0.9 m. Typically, cabins have 2 rows of filters with a total height of 1.8 m. There are models of increased height, in which filters are installed in 3 rows - 2.7 m in height.

Remember that for any task you can choose the optimal solution!

If you paint a car, you probably do it in a paint booth. To comply the right technology you have to make sure that everything auxiliary equipment At the same time, it worked as it should, including ventilation. The spray booth itself must be designed to ensure that the spray hood works properly.

The main danger to humans when working in a paint booth is the toxic gases released during the evaporation of the coloring substance. Vapors also come from the solvent. Thus, competent organization workspace is the most important task. Constant air circulation is necessary. For this purpose, provision must be made for the installation of supply and exhaust ventilation. At the bottom of the chamber you need to mount a hood with filters.

If you look at the paint booth from the point of view of organizing the hood, we can say that this is a complex system, since during operation it must ensure an even coating of the part, without drips or defects. Therefore, air flows must be carefully calculated. Extraction of paint vapors is necessary to clean the air inside the chamber, as well as to ensure sedimentation of the paint suspension and its filtration.

So, the hood for a paint booth in normal operation provides the following conditions of the internal environment:

Feeding at up to 30 degrees Celsius;
Removing exhaust air from the premises and discharging it outside;
Providing a supply of fresh oxygen.

To ensure that the air coming from outside is clean and does not interfere with the painting process, it passes through dust-retaining filters. Also, to prevent paint vapors from getting into environment and did not have a toxic effect on it, paint-retaining filters are used.

If we express the volume of circulating air in numbers, it can be represented as a multiple of the volume of the room to the supplied and exhausted air - then the figure will be 140-200 times per hour. Roughly speaking, this can be compared to continuous air circulation.

Types of ventilation systems and their comparison

Traditionally, there are several types of chamber ventilation:

Single-motor chambers are rooms that receive air from the top of the room. The created air flow puts pressure on the paint vapor, and it sits on the floor and then is discharged outside;
Dual-motor cameras, in addition to the motor at the top, have another engine that sucks air from the room through the bottom of the camera.

Both extraction methods have their pros and cons. However, there is one thing to consider. The choice of camera depends on the expected scope of work. Twin-motor exhaust systems, of course, provide much better air circulation, but they are quite expensive and very labor-intensive to install in a paint booth. An exhaust hood for a paint booth, through which dozens of cars will not pass a day, can also be single-engine: this is a more economically viable option. In any case, there must be some kind of hood.

The filter for the spray booth must be installed of high quality and, of course, it must be replaced in a timely manner if you do not want defects to appear on the part.

A fine filter is installed at the outlet of the air duct. The air box is traditionally installed under the ceiling and is the source of air injection into the room.

Speaking about the second ventilation option that we mentioned, we note that dirty air is removed through holes in the floor of the chamber. The holes are followed by trenches through which air is conducted. Grills should be placed over the openings to prevent them from becoming clogged. Trenches can be dug into the floor, but you can simply raise the floor itself.

Supply and exhaust ventilation

Meanwhile, human invention does not end with the two methods of ventilation already mentioned. There is another method that most painters prefer - this is an injected exhaust ventilation. It can work not in one, but in three different modes.

Active circulation of the flow passing through continuous filtration and returning back to the chamber. Such cleaning is necessary immediately before painting to clean the room and prevent dust from getting under the paint layer;
Air is taken from outside, filtered and heated or cooled to an acceptable temperature, then entered into the chamber. The air is then discharged outside without filtering. This mode is suitable for simply maintaining the desired temperature and suppressing fog;
Air is pumped from the chamber, passes through the filtration system and is heated to 60 degrees. It then flows back into the chamber, drying the surface of the car. Accelerated drying is necessary for large volumes of work.

When you design a ventilation system, pay due attention to how its inlets and outlets are located. Incorrect positioning can result in blind spots where air cannot circulate. A suspension of paint will remain there and then settle on objects.

This, of course, complicates the work and degrades the quality of painting. If necessary, you can install local hoods to increase the efficiency of the main system, but make sure that the operation of all these units does not interfere with each other and does not create air turbulence.

Filter for spray booth

Filters that are used to clean the air in paint booths quickly become clogged with dust and paint. Then the volume of circulating air is greatly reduced, and its renewal is not enough for comfortable work. This is not a tragedy, since the ventilation system necessarily has an air supply power regulator.

In addition, filters are usually very easy to replace if necessary. The problem can also be solved by using two-stage filters. They significantly increase the service life of air filters. While external filter prevents dust from entering the room (the filter holes are larger), the internal one is engaged in more fine cleaning.

It traps very small dust particles, flying drops of paint, as well as varnish compounds. If you clean the external filter in a timely manner, you will need to replace the main filter much less often. Large particles of dust are much easier to remove from the mesh so that it can be reused.

The air flow rate must be analyzed in real time. The painting booth must be equipped with special sensors. The flow speed should be within 20-25 cm/s. To the calculations, of course, it is necessary to add the volume of the car, or rather, subtract this indicator from the volume of the room.

Necessary calculations

In order for your spray booth to work correctly, you must calculate required volume ventilation in the room. If you make the calculation correctly, toxic gases and dust will not accumulate in the room. This will not only protect the paint operator, but will also improve the quality of the painted surface. You will also comply with fire safety requirements, since the accumulation of toxic volatile gases in a small space is a fire hazard.

There are, of course, difficulties. The volume of circulating air depends on the size of the part to be painted. So, to paint a small part, the air exchange rate should be five times per hour. Naturally, painting a car requires, as already mentioned, more than 140 times.

We see that in large chambers it is unprofitable to paint very small parts - this is quite logical. But the circulation should not be set too low, otherwise it may negatively affect the health of the painter. Modern paint booths are often automated, so workers don’t have to worry about ventilation.

However, if the hood is not automated, you will have to select it yourself required quantity revolutions for each fan separately - for the upper and lower. At the same time, you must know their performance and the pressure created.

You can rely on the sensor readings harmful substances or at own experience. The fan pressure is calculated depending on the area of the ceiling filter - for the upper motor - and depending on the area of the floor filter - for the lower one.

An ordinary painting booth is traditionally characterized by a certain air exchange capacity - on average, 20 thousand cubic meters per hour. Such performance can guarantee not only high quality parts after paint treatment, but also safe conditions for the operator.

Do-it-yourself supply and exhaust ventilation

If you have already built a box yourself in which you will paint parts or entire cars, you can make a hood yourself. Please note that the installation of the hood can only be done after you have completely finished decorating the room: you have lined the walls, installed light.

Traditionally, walls are sheathed in this case with sheets of metal or plastic lining. It is better to use fluorescent or LED bulbs: they are economical and safe to use, this is especially important in a flammable room, such as a paint booth.

Provide a light output of at least 600 lumens. Insufficiently powerful lighting can fail if there is too thick a fog of paint around. But this will not happen if you properly equip the ventilation: place the hood in the floor of your garage, and the air intake with a heat gun in the ceiling.

However, as you have probably already noticed, hood designs can be very different, and you can experiment more or less freely. A self-made hood in a paint booth will work no worse than a factory one if you use high-quality components.

People often face the problem of uneven ventilation. To avoid this I like experienced master, I advise you to equip air ducts so that they distribute air flows from the heat gun evenly over the entire surface of the garage.

Probably everyone knows the structure of a heat gun, so you can also make it yourself. A heat gun is a large fan that drives air from outside through high-temperature heating elements. If you undertake to do heat gun yourself, instead of heating elements you can use nickel-chrome wire.

You will need to install about seven to eight heating elements or their substitutes. Then the air in the chamber will be heated to the desired temperature. If you have neither tens nor the required wire, use a heat generator. He runs on diesel fuel.

After installing the system, be sure to test it. Based on the calculations, adjust the exhaust power to paint parts of a particular size or to process an entire car. Painting in a booth should be done by an experienced painter; There should also be a partner who monitors the serviceability of the ventilation system in order to prevent the paint booth from filling with gases if it breaks down.

Hood safety

Finally, pay attention to how secure the system is. Development effective system ventilation helps not only to achieve excellent quality painting, but also maximum safety during work. There are three ways to do this important system as safe as possible:

Install explosion-proof check valves on the air ducts;
Keep records of those impurities that are formed as a result of work;
If necessary, install additional local exhaust motors to help improve the atmosphere in the box.

Consider in advance whether the impurities and vapors released during painting will be heavier or lighter than air. In the first case you need more attention give exhaust holes near the floor. It is necessary to design the hood in such a way that only a third of the total circulating air is removed from the upper chamber, and the main part from the lower part. You need to do the opposite if the expected vapors are lighter than air and, accordingly, will mainly accumulate at the top.

If you additionally install jet painting units, you will even need local explosion-proof hoods. It's a good idea to install a couple of these hoods above the painting table, stand or near the paint bath.

We see that calculating a ventilation system is a responsible job that may be better entrusted to a professional. From proper operation ventilation affects people's lives and the quality of painting.

And if you intend to perform work for other people, your reputation as an expert and professional depends on the hood. After reading the tips outlined here, you could choose some ready-made system hoods, of which there are a lot in specialized stores.

If your choice is to create your workshop from scratch, on our own, then make sure that you have sufficient competence in this matter, read more professional books, look through the World Wide Web. And then you will definitely succeed.

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