Let's figure out what types of cameras there are for painting furniture parts. Depending on how many and what sizes the parts will be painted, what paint and varnish materials you will use, the required one is selected spray booth.

2.

• water spray booth without side walls and floor (front curtain only)
• water spray booth with active water floor
• water spray booth without floor with side walls
• water spray booth with active water floor and side walls
• water spray booth with active water floor and active water walls
• small painting booths, otherwise small-sized or laboratory ones for painting small products in piece production, instrument making, 1 and 2 meters long.

Spray booth with dry filters

Due to its design, when painting in a dry spray booth, excess paint mist and contaminated air are removed from the paint application area, while cleaning it. All this works when correct selection fan

What happens when using a spray booth with dry filters?

Dry when working spray booth the following processes occur:

• removing paint particles and dust from the spray area
• removal of paint aerosol, while preventing its spread into adjacent rooms
• conditions are provided for receiving paint coating High Quality
• the air that is removed from the painting area is cleared of mechanical paint particles that remain in the filters and released into the atmosphere.

How is air filtered in a dry spray booth?

The air flow, which is contaminated with paint and varnish products, with the help of a fan moves by inertia into the opening of the chamber where it is installed one or two filters.

What types of filters are there for a dry spray booth? Filters for dry spray booths are: Cardboard filter The principle of operation of a cardboard filter is as follows: particles of paint and varnish hit the inner wall of the filter several times and settle there, and the air continues to move by inertia, with no loss of air speed during suction. An example of calculating the filtering capacity of a dry filter For example, you have a dry spray booth 2 meters long with a suction area of ​​3.6 sq.m. This area corresponds to two pieces of cardboard filter 0.9 meters high and 2 meters wide. The filter holds about 15 kg of paint per 1 sq.m. It turns out that the filter of our spray booth will hold 54 kg of waste paint. To calculate, we simply multiply the holding capacity of the filter by its area: 15 kg/sq.m.*3.6 sq.m. = 54 kg. Glass fiber filter The fiberglass filter is made of fluffy interwoven glass fiber that is impregnated with a special compound. The filter retains paint mist particles. The fiberglass filter can be used as the only or second level of air purification from paint mist. In the version of the second level of filtration, this filter is installed behind the cardboard filter. Often, a fiberglass filter in a roll is installed on the floor of car cameras, hence its second name – “floor”. The service life of such filters is short, only 60 hours of coloring.

How long does a dry spray booth filter last? This question, undoubtedly, in addition to the technological part, also has an economic component. The basis for calculating the “lifetime” of a dry filter is the following components: How many kilograms paint and varnish materials You spray per day what kind of paint guns do you use, that is, what losses of paint materials occur due to fogging? what products are painted how they monitor the cleaning of spray booths and replacement of filters. Example of calculating the lifetime of a dry filter For example, you again have a 2-meter dry painting booth, paint consumption per shift is 20 liters per day (excluding solvent), you use a paint sprayer with a traditional spray system, the material transfer coefficient is 40-45%, that is, 8 liters out of 20 liters of paint flies into the fog. Ours showed that it can hold up to 54 kg of paint. It turns out that one filter replacement will last 54/8 = 6.8 days, that is, about a week of work. And if you bought a roll of filter, then it will last for a month, you can figure out how much money it will be for yourself.

Spray booth with water curtain

A spray booth with a water curtain ensures maximum cleanliness and dust removal in the painting area. All this allows you to create ideal conditions for obtaining a high-quality glossy paint finish.

The frontal water curtain captures paint mist, and the air flow created by the fan additionally draws in contaminated air.

Video. 2. Spray booth with water curtain

What happens when a spray booth operates with a water curtain?

When operating a water spray booth, the following processes occur:

• removing paint particles and dust from the spray area
• removal of paint aerosol and eliminating the possibility of its spread to surrounding areas
• security ideal conditions to create high quality coatings
• the removed air is cleaned of mechanical particles of paint and part of aerosol vapors and released into the atmosphere.

How to care for a spray booth with a water curtain?

The first thing to do when operating a chamber with a water curtain is replacing the water. They change it depending on the degree of contamination in the cabin.

How quickly the chamber gets dirty depends both on the intensity of painting, that is, how much paintwork is applied per shift, and on the paint guns used. In spray guns with a low material transfer coefficient, a lot of paint is spent on fogging, which means more paint settles in the cabin. If the water is dirty, it will be less able to capture paint mist and dust.

How do you clean water from paint in a spray booth with a water curtain?

In small factories, water is simply poured into the sewer, which is basically impossible, and the accumulated paint at the bottom is scooped out with shovels and other available means.

“Advanced” companies use coagulants and a collection of paint waste to remove paint. The addition of a coagulant allows the paint to turn into flocs, which precipitate or float to the surface as flakes. Flakes are removed manually or using a waste collector.

How is air purified in a spray booth with a water curtain?

Water spray booths have three levels of air purification from paint:

1. On the first level air cleaning performed using a frontal water curtain. A stream of water flows down this part of the chamber in a continuous and continuous stream.
2. At the second level, internal air purification occurs; here the main filtration and purification of the air from paint waste takes place. Depending on the design of the spray booth and the manufacturer, there are various internal air purification systems.
3. At the third level, dry filtration is carried out - the air is cleaned of remaining paint particles and protects the fan blades from paint sticking.

Water chamber design diagrams

U different manufacturers The filtration systems of paint booths differ; for example, here are several diagrams of water-based paint booths.

What length and width should I choose for a spray booth? If maximum length the parts to be painted are 2.7 meters, then the required length of the cabin is 3 meters, and if it is 1.8 meters, then 2 meters are needed. If you want two painters to work in the booth, then multiply the numbers by two, at least. The depth of the cabin depends on the size of the room in which the painting will be carried out. If the painter will be inside the cabin, then focus on maximum dimensions painted parts. If the room is, for example, 4 meters, and the cabin is 3 meters, then the cabin can be installed without side walls. Again, if two booths are installed side by side, then side walls are required so that there is no spray from the adjacent chamber.

Example of a paint booth from furniture production

Here are photos of a paint booth that were taken during a tour at a real operating enterprise.

Painting booth with a water curtain»>An excellent business solution is to paint cars at home. But in order to be able to paint cars, there is little experience and equipment for painting; you also need to have a room in which the vehicles will be painted. Organizations that paint cars have long carried out painting work in a chamber with a water curtain. It is no secret that such a device can be made with your own hands, only by making some effort and spending a small amount of money to purchase some equipment. You can buy a ready-made one, but its cost will be very high, and not everyone is ready to invest a large amount. In order to make a device with a water curtain with your own hands, you will also need some knowledge.

A spray booth with a water curtain is closed room, which is made from of stainless steel and has supply and exhaust ventilation. This ventilation is created using electric motors. The main part of the device is a heating element, which helps heat the room to the required temperature and maintain it during painting work. The chamber also includes lighting, which must be distributed evenly over the entire area and have sufficient luminous flux. It is best to place them not only on the ceiling of the room, but also on the side walls. The device also includes equipment for painting work and other auxiliary tools.

Layout of the painting booth

Knowing what the paint booth consists of, you need to decide on the location where the arrangement will be made, and make a project according to the location of the main structural elements. An excellent location for the construction of the device can be a garage, or build a new extension, which will take more time and, accordingly, finances. To make a device with your own hands, you will need structural elements from which it will be based, heating and ventilation systems, filtration and lighting.

Diagram of a spray booth with a water curtain

Making a painting booth

Having made the layout, you need to carry out everything technical calculations, and begin installation work.
First of all, a new room is built or a frame is assembled inside the garage. General dimensions should be: length 10 meters, width 8 meters, height 3.5 meters. The painting booth has a corresponding size: 4 meters wide and 6 meters long.

1. 1. Gate installation.
      It is best to use insulated gates to avoid suction and loss of warm air; the outside is lined with corrugated sheeting. At the point of contact between the gates, it is insulated with a special adhesive tape. Places with cracks must be foamed with foam.
   2. Floor construction. The base of the floor is made of concrete, inside which a hole is made, and a metal pipe with a diameter of 150 mm is led out onto the street for air outflow. A metal grate is placed on the floor over the entire surface of the room to a height of 15-20 cm.
   3. Walls. The walls are sheathed with corrugated sheets, and the inside is insulated; sandwich panels can be made.
   4. Air exchange system. Components: two electric motors and metal pipes with diameters of 100 mm and 150 mm respectively. An electric motor with a power of 5 kW is used for supply ventilation, and at least 7 kW for exhaust ventilation.
   5. Ceiling. It is made of corrugated board, with insulation. Ceiling mounted metal carcass for air flow. An electric heater that will supply warm air indoors, installed outdoors.

1. Air cleaning. It is carried out using filters and has three-level cleaning.
   • Level 1 A frontal water curtain is created, which is carried out by flowing down uniform streams of water;
   • Level 2. Cleaning the air inside the device. Promotes filtration and purification of air from paint waste;
   • Level 3. Dry filtration. Helps completely clean the air from paint particles and protects the fan from paint sticking.
2. Lighting. Mounted LED or fluorescent lamps along the ceiling and walls of the room.
   Automatic control and monitoring sensors are also installed over the system of supply and exhaust fans and filters.
   After installing everything necessary for the water chamber, painting equipment is installed.

How the work is carried out

An electric heater pumps air from the atmosphere into a confined space in a room. As the air passes through the system, it is purified by filters, each of which provides a specific purification.
The temperature in the room rises due to the work of the heating elements. The painting process begins. Down on the floor, air begins to be sucked out of the chamber using an exhaust fan. Water curtains are installed in front of the main line, which help retain paint particles. Here the air goes through all three levels of purification, if such are pre-installed. Cameras with a water curtain and factory production work on the same principle.

Positive aspects of a DIY device

1. Free system planning.
2. Big savings.
3. Possibility to save on all components.
4. Ability to use the main parts of the structure.

Disadvantages of the device

1. There may be inaccuracies in calculations or imperfections in the installation of the device.
2. It is not possible to completely automate the process, since the elements of the device consist of separate parts.
3. There are no guarantees for the performance of such a device.

Price

The cost of constructing a water curtain chamber with your own hands can take a long time, but it will cost about $4,000. You can buy a factory one for $20,000 or more. To start a business, the best option There is a construction with your own hands, which is much more profitable for a start-up business.

Paint booths with a water curtain are perhaps the most advanced design option for painting systems. Equipment of this type is used for painting large-sized products, including car bodies, or individual body parts, various furniture structures, etc.

Any spray booth is based on the fact that air moves inside the system, which carries with it mist from the paint, which evenly settles on the surface to be painted. And if in a traditional paint booth there is a possibility that harmful substances or paint particles will come out of the chamber, then in chambers with a water curtain the paint particles are retained by water. Moreover, water molecules bind molecules of harmful volatile substances, which are found in excess inside the paint booth.

Thus, hitting harmful substances into the surrounding atmosphere is sharply reduced. But it cannot be said that a water curtain provides a complete guarantee that the emission of harmful substances into the atmosphere is completely excluded.

In addition, there are chambers that operate in a partially closed air movement cycle. In this situation, it turns out that the air that has already been in the chamber enters it in the next cycle. And if it is not sufficiently cleaned before reuse, paint particles that have already begun to polymerize will enter the chamber along with the air. And this can significantly affect the final quality of the coating. And the water curtain, which can have different designs, traps paint residues.

How do water curtain spray booths work?

The principle of operation of a waterproof spray booth is very similar to traditional spray booths. Air is sucked from the atmosphere into the enclosed space of the chamber. Air is sucked in due to the operation of the fan. The air enters through a system of filters, each of which provides a certain level of purification. How smaller hole in the filter material, the finer the purification.

During the painting stage, the air heats up when passing through special heating elements. The temperature in the chamber begins to rise.

There are exit holes at the bottom of the spray booth. Moreover, they can be located in different places in the chamber (depending on the hole). Through these openings, air leaves the enclosed space of the chamber due to the operation of suction fans. And it is in front of the main line, which works to remove air from the chamber, that water curtains are installed, which can also have a different design. Essentially, the air mixed with paint that comes out of the chamber passes through a thin wall of water. And all suspended particles remain in this water.

The water curtain can be considered as a water filter. Although there are options when the air does not pass through a wall of water, but through a special container with water. In this case, solid particles gradually accumulate at the bottom of the container, which then fall out as sediment to the bottom of the container.

In order to activate the process of binding harmful substances in the air with water, a special reagent is added to the container, which is a catalyst for chemical reaction cleaning.

The most advanced water curtain spray booths support multiple levels of air purification. The first level is when air passes through the front water curtain. The water flows solid wall, and the speed of water movement is the same all the time. Water covers the entire surface of the front part of the curtain.

At the second level, a more subtle cleaning of the air from paint particles occurs. This is the so-called internal cleaning level. According to experts, it is at this stage that the most complete purification of the air from paint impurities occurs.

The finest cleaning occurs on final filters, which can be made on the basis of hydrocarbon technologies (carbon filters) or dry filters, which are made on a different basis. Here literally all remaining paint particles are removed. This protects the fan blades from paint residues sticking to them.

Spray booth with water curtain mod. W3000 is designed for:

• significant improvement in the quality of paint and varnish coatings;
• significant reduction in maintenance time for painting areas;
• increasing the productivity of painting areas;
• ensuring acceptable sanitary and hygienic working conditions for painters and support staff;
• immediate removal of solvent vapors from working area, in order to prevent the formation of explosive concentrations;
• significantly reducing emissions of paint and varnish sludge into the environment;
• reducing the fire hazard of the paint job.

Areas of use

The W3000 water curtain spray booth is successfully used for painting metal, glass, wood, plastic and products made from them.

The range of painted products is very wide:

• painting wheel rims
• painting of large metal structures
• painting of garden and agricultural equipment
• painting drills
• painting pipes and poles
• painting piles
• painting welded air ducts
• painting formwork
• painting elements of building structures
• painting cement-fiber boards and other building and finishing materials
• painting (varnishing) of electronic boards and components
• painting aircraft parts
• painting elements of boats and boats
• car bumper painting
• restoration of furniture and antiques
• painting furniture
• painting MDF facades
• painting tables
• painting chairs
• window painting
• painting doors
• painting molded products (door moldings, skirting boards)
• painting parquet and floor boards
• painting of other furniture and joinery products

Principle of operation

Some of the paint and varnish material sprayed by the painter does not fall on the product. At the same time, fine dust from the quick-drying components of the varnish is formed in the air - dust, which, thanks to the painting booth is removed from the working area by an air flow parallel to the floor.

A significant part of the varnish dust is deposited on the water curtain (up to 85%).

Additional filtration systems (optional) - a labyrinth of barrier panels that repeatedly change the direction of air flow, as well as quick-release cassettes with an inexpensive replaceable element - a fiberglass filter - allow achieving a degree of purification from solid particles of up to 99%.

A “side effect” of using water in the filtration system is the absorption of solvents when the chamber begins to operate. After the water is saturated with solvent molecules, the absorption of “odors” stops, and the illusion of their filtration disappears.

Basic equipment

Prefabricated body and settling tank made of galvanized steel with a large number of longitudinal, transverse and vertical stiffeners.

Provides durability and reduced vibration during operation.

Double cascade of water curtains.

The front curtains of both cascades (those through which water flows) have a quick-release design. Thanks to this, not only is full access to the interior of the chamber for maintenance provided, but it also makes it technically possible to narrow the gap between the lower edge of the curtain and the water in the bathtub located below. For the upper cascade, this is the bath of the lower cascade, and for the lower cascade, this is the settling bath.

This design has a number of advantages, the main ones being:

• due to the absence of long sections of free fall of water, the formation of splashes in both the upper and lower parts of the working area is eliminated;
• water rushing off the lower edge of the water curtain creates a dense flow that additionally cleans the air of suspended particles, which eliminates the need to install water sprinklers;
• the speed of air flow after entering the painting booth is reduced by 4-5 times, which allows suspensions to settle into the settling bath, increasing the degree of purification of the emitted air.

1. Attached bath to accommodate the pump>

   The location of the bath is universal (to the left or to the right of the camera). In this way, the service side can be selected during installation.

   The location of the service area outside the chamber allows for visual control operation and avoid external contamination of the pump, which leads to its overheating and premature failure.

   Valves located outside make it easy to regulate the water flow in the water curtains, as well as to quickly drain water from the chamber using a standard pump during its scheduled maintenance.

   A stainless steel pump that pumps lumps of coating sludge with a diameter of up to 35 mm, as well as a built-in overheating protection system.

2. A system of circulation water lines, including a water circulation valve, an automatic water drain valve, all necessary hoses, passage units, flanges, clamps and other installation materials
3. Mounting kit including bolts, nuts, washers, sealant, etc. according to camera configuration
4. Packaging for transportation by road
5. Passport and instruction manual
6. CD with diagram and photo illustrations of the assembly

Additional options

Explosion-proof exhaust fan.

Explosion-proof design, with an explosion-proof motor (optional - with a general industrial motor or not explosion-proof).

1a- Fan with a wafer-type supporting body. Thanks to installation via rubber gasket directly on the roof of the chamber and the placement of additional amplifiers in the fan installation area, the vibration resulting from clogging of the fan blades during intensive operation of the spray booth is minimized.

The fan motor together with the impeller is completely removed from the housing. To do this, you do not need to caulk the air ducts or disconnect the electric motor from electrical network and so on. This fan design minimizes maintenance time.

1b- Fan with supporting frame. The fan can be installed in any convenient location, incl. outdoors, and is connected to the chamber by an air duct (the air duct is excluded from the supply).

The design provides the ability to remove the motor together with the impeller from the fan housing without caulking the air ducts. This ensures ease of maintenance and minimizes technological downtime of the painting chamber.

Additional air filtration devices

The combined use of devices allows achieving a degree of solid particle removal of up to 99%.

2a- A labyrinth of barrier panels that repeatedly change the direction of air flow. At the same time they serve as additional diagonal stiffeners. Recommended for installation when placing the fan on the roof of the chamber.

2b- Quick-release filter cassettes with an inexpensive replaceable element - a fiberglass filter.

Electrical control panel

3a- Shield in a plastic case with automatic switches– for placement outside the hazardous area

3b- Shield in a metal case with on/off/emergency shutdown buttons – for placement outside the hazardous area.

Explosion-proof fluorescent two-lamp lamp, 2x36W. The lamp is supplied with 2 lamps.

Increasing the depth of the working area by 500 mm

Set of two side panels and a roof panel.

Water floor

The water floor bath is integral with the settling bath of the paint booth and has a height of 300 mm from the workshop floor level. Thus, no gangways are required, making it easier for the operator to move around. The large volume of water filling the bath allows you to increase the interval for cleaning paint materials from accumulated sludge, reducing process downtime. Galvanized gratings covering the water floor can withstand a footprint load of at least 200 kg and 450 kg/m2.

1. The supply fan and set of filters for the “economy project” include:

   • Supply fan of general industrial design. To create in a paint job overpressure, the performance of the supply fan is selected to be 10-20% higher than the exhaust fan, taking into account the fact that additionally the resistance of both the pocket filter and the filter of the air distribution device must be overcome.
   • A pocket filter in its own housing, designed for connection with the supply fan. The filter design is quick-release. The filter is designed for repeated use. Its regeneration is carried out manually, mechanical cleaning and purging.
   • A roll of fine filter (20x2 meters) for the buyer to independently sew an air distribution hose.

. on organizing the supply of painted products, ─ on dead-end and through passages. In individual production, periodic dead-end spray booths are more often used, and in large-scale production, continuous spray booths are used.

. spray booths can be open and closed (open and closed type). Closed spray booths ensure complete isolation of the working area from the surrounding area. This allows, due to the coordinated operation of the supply and exhaust ventilation, maintain a pressure inside the chamber that is different from atmospheric pressure, thereby preventing the uncontrolled emission of contaminants. The body of the open spray booth forms a partially enclosed space. The number of open openings depends on the painting technology, the location of the workplace (outside the chamber or in the chamber) and the method of loading and unloading the painted products.

. features of the filtration system design give reason to distinguish two large classes of spray booths ─ dry spray booths And chambers with hydrofilter.

Chambers with a water curtain in regulatory documentation

A number of current regulatory documents speak about how important, and often necessary, a spray booth with hydrofilters or a spray booth with a water curtain is.

“The air sucked from the painting booths, booths and floor grilles is cleaned from the resulting aerosol of paint and varnish material. Cleaning should be carried out, as a rule, by the “wet” method in hydrofilters.” This provision contains « Sanitary rules during painting work using hand sprayers. Sanitary and hygienic characteristics of working conditions" .

Resolution of the Ministry of Labor of the Russian Federation dated May 10, 2001 No. 37 “On approval of inter-industry rules for labor protection during painting work” even more categorically. Clause 3.52.: “Exhaust air from rooms for working with paintwork materials, local ventilation systems and local suction must be cleaned from paint aerosols using a “wet” method in hydrofilters.”

Not only the sanitary and hygienic aspect is important, but also the requirements fire safety. "PPBO-109-92. Fire safety rules for railway transport» : “Painting work by spraying paints and varnishes must be carried out in spray booths made of fireproof materials and equipped with hydraulic filters. Without hydrofilters or other effective devices for catching aerosols of flammable paints and varnishes, it is not permitted to operate the local suction system of paint cabinets, chambers and booths.”

Color is very important

Paint booths are a relatively new type of equipment, in contrast to paints or paints and varnishes, which humanity has been using for tens of thousands of years.

At least, this is the age of the oldest rock paintings, for which mineral powders were used, charcoal, lime, clay, and later animal fats, the secretion of the glands of living beings and other biomaterials. The chemical industry has added to this arsenal with a variety of synthetic paint compounds that have made the world much brighter. Of course, the brightness of the sky, water, minerals and plants remained the same, but the noosphere (or anthroposphere) sparkled with all the colors of the rainbow. This happened again. and because color, being integral part design, has become one of the essential tools promotion of many products, incl. industrial products. Besides thin layer paints have acquired important economic importance, protecting millions of tons of steel products and structures from corrosion.

How important color is, and therefore painting equipment in general and paint booths in particular, can be judged by the example of the automotive industry and the huge car service industry, which creates hundreds of thousands of jobs. For them, the quality and cost of coloring are one of the main trump cards in competition, A functionality paint booths largely determine the economic efficiency of production.

Prerequisites for the appearance of paint booths

have developed in the second half of the 19th century. In 1887, the method of spraying paint compositions was invented in the USA. (This, by the way, stimulated the emergence of paints and varnishes with previously unprecedented properties, for example, quick-drying ones). First new technology adopted by furniture manufacturers . But soon, and on a much larger scale, it began to be used in the rapidly growing automotive industry.

Interest in spray painting from many industries has given a powerful impetus to the development of enterprises producing such devices. But at the same time, he definitely set them the task of ensuring acceptable working conditions for the personnel operating them. The answer to these challenges was painting booths, with the help of which it was possible to localize the influence of paint fragments that were not fixed on the surface being painted - the so-called. "colorful fog" Fogs, as a rule, are called aerosols, the dispersed phase of which is represented by liquid droplets . Of course, the pollution that accompanies the dyeing process, often very toxic, is not limited to mists; it is enough to remember such a component as solvent vapors.

Already at the beginning of the 20th century, means such as an orderly air circulation system and air purifying filters were used to implement a technological concept that was innovative for that time. No matter how outwardly similar the installations depicted in photographs of the first half of the 20th century were to modern paint booths, they have changed a lot. Because as a result of scientific and technological progress, dry and hydrofilters, fans, pumps, equipment for applying paintwork materials and paintwork materials themselves have changed (just remember powder coatings, for the application of which powder painting booths are used).

The range of tasks solved using paint booths has expanded. As at the beginning of their existence, they help minimize harmful effects paint and varnish compositions for the health of workers , only today against the backdrop of more stringent and detailed requirements of national legislation in the field of labor protection. To this was added another most important task, which at the beginning of the 20th century was not yet so pressing: reducing the burden on the environment .

And of course, the use of spray booths allows ensure modern standards of painting quality , thanks to filtration systems supply air, removing even the finest dust. And due to automation technological processes and increasing energy efficiency, it is possible to increase productivity and make the painting process more economical.

Water spray booths successfully cope with these tasks. They are convenient to use, since the presence of hydraulic filters simplifies the cleaning of fans, filters, pipelines and air ducts from paint particles. The presence of water improves fire safety and minimizes the possibility of increased concentrations of explosive substances. Water curtains with high efficiency clean air contaminated in the working (painting) area from solid particles of paint and glue, solvent vapors, aerosols and other contaminants.

The principle of operation of any spray booth is to create a directed air flow. Outside air enters the work area. The quality of coloring will be higher, the better it is prepared, ─ using filters it is cleared of solid inclusions, it has desired temperature and humidity. Already in a “spent” form, contaminated in the work area as a result of contact with paintwork materials, it is cleaned by exhaust ventilation filters and discharged into the environment.

If part of this work is performed by hydrofilters, such devices are called water spray booths or water curtain booths. “Part of the work” ─ since the presence of hydrofilters does not negate the use of dry filters working together with them, usually located in front exhaust fan final fine filters.

Hydrofilters

Since the basis for separating painting booths with a water curtain into a separate class of equipment was the use of hydrofilters, they (hydraulic filters) have earned the full right to be presented first when considering the design of such chambers.

The term " hydrofilter " in this case means air filter, purifying the air using water as a filter material. The “in this case” clause is due to the fact that hydraulic filters are sometimes called hydraulic filters, i.e. filters used to purify liquids in hydraulic systems.

The use of air hydraulic filters is not a monopoly of paint booths. For example, they are installed in ventilation systems to cool air, protect against sparks, remove soot, soot, grease, and eliminate foreign odors.

What is common to all hydrofilters is that polluted air is purified when it interacts with water. Depending on the design, screen (cascade), nozzle and nozzle-less hydraulic filters are distinguished. They differ in the principle of supplying air-purifying water and, as a result, in their operating features.

In screen hydrofilters, water curtains are created using overflow water distribution devices and panels. In nozzle systems, nozzles are used to form water curtains.

Pump and pumpless bubble-vortex hydrofilters are also used, in which air purification occurs as a result of its active mixing with water. Their name comes from the French barbotage - stirring. The principle of operation is passing gas or steam (in our case, air) through a layer of liquid (in our case, water).

In the screen hydrofilter air flow, containing paint particles and solvent vapors, is fed onto a screen covered with a continuous layer of water flowing over it, the circulation of which is ensured by the operation of the pump. When faced with water, large particles lose speed and flow with it into the bath located under the screen. Contaminants that have overcome this barrier are removed when the air flow passes through water curtains located behind the screen. A drop eliminator capable of “processing” vertical and cross air flows helps make the air cleaner.

Along with the front ones, side curtains can be installed. More effective capture of paint mist is provided by an active water floor (or active water pan) ─ a bath covered with a grid, possibly buried in the concrete floor of the workshop.

In nozzle hydrofilters, water is sprayed using nozzles. As a rule, screw or tangential with a hole diameter of several mm.

Screw nozzles form a more stable spray, but tangential nozzles are easier to manufacture and less likely to clog. The pitch of the nozzles is set depending on the angle of the jet cone (usually 70-75º) and effective length torch.

A shield made of sheet steel or polymer materials installed between the rows of nozzles helps create a directed air flow, preventing it from getting between the water jets.

Water consumption depends on the speed of its flow along inclined panels or screens, as well as the number of curtains and their cross-sectional area (i.e., the thickness of the water layer, which is usually several mm). The water circulation is almost closed. Almost ─ because due to losses due to evaporation and removal of particularly polluted waters, its supply has to be periodically renewed. Sludge from hydraulic filters of paint booths with a water curtain is accumulated by a special system for purifying water from paint waste.

To prevent constantly moving water from foaming, anti-foaming additives are added to it.

The case is “classic” and not quite

A mandatory attribute of a spray booth is the body. This is not always a “classic” building with a floor, walls and roof. It may consist of only one front wall. There are tubeless coating technologies used, for example, for painting large-format products. And in many such devices the air is purified using hydrofilters. They may have different design. For example, tubeless installations with bottom suction, consisting of a hydraulic filter, an exhaust ventilation system and a pump unit. For coloring vertical surfaces lifting platforms equipped with a hydrofilter are used, ─ air contaminated with paint particles is drawn into the gap formed by the surface to be painted and the wall of the hydrofilter of such a platform.

The presence of side walls and a roof helps create a directed air flow and prevents entry into working space contamination from painting booths located nearby.

Paint booth bodies can be solid or modular. The most common material for their manufacture is sheets (panels) of galvanized or stainless steel with a thickness of 0.8-1.5 mm. There is experience in using plastic with an anti-adhesive coating, with a thickness of 10 mm or more. The advantages of this solution are that paint residues adhere less easily to the camera surfaces and are easier to remove.

The dimensions of painting booths are determined by the organization of work and the size of the products for which they are intended for painting. Organization of work ─ this is where, ─ inside or outside the chamber, ─ located workplace, whether it is necessary to rotate the products during the painting process, whether overhead conveyors with a swing amplitude are used for their transportation, etc.

Ventilation system

The ventilation system ensures the required direction of movement and uniformity of the flow of exhaust air to be cleaned ─ from the working area to the hydrofilter.

Typically centrifugal and axial fans middle and low pressure, the parameters of which are determined based on the amount of air that must be removed from the spray booth per unit of time. The fan can be installed on its roof. But at the same time, especially in the case of powerful and high-speed fans, it is necessary to prevent noise and vibration effects on the camera body.

Into the open spray booth fresh air or the main part of it comes through open openings directly from the workshop, and its deficiency in the room is compensated by the workshop forced ventilation. To increase the amount of air used by the spray booth, an air inlet pipe equipped with a valve that opens when the spray equipment is operating can be used. This is relevant for paint booths located in small rooms.

Trends in the development of painting technologies used in mechanical engineering, woodworking, the production of building and other metal structures, ─ wherever painting booths with water curtains are used, ─ are determined by the progressive tightening of protection requirements environment and sanitary and hygienic requirements, as the most important segment of labor protection. And also the need to increase economic efficiency by increasing labor productivity, energy and resource conservation, and improving the quality of work.

You can comply with them by increasing the efficiency of filters, using new construction materials, energy-saving ventilation and pumping equipment, increasing automation and robotization of technological processes. This means that spray booths with water curtains will have to change. More in content than in form. However, this is exactly what they have been doing for many decades.