How to choose a spray booth with a water curtain. We paint cars in the premises of our own production

If you decide to do car repair, then you need to get a spray booth.

The safest and fastest way to get it is to contact the Ural Machine Tool Company in Yekaterinburg. Our experts will be able to quickly find the option that suits you at reasonable prices.

Of course, there is another way, but it is more complicated and, unfortunately, not entirely reliable.

We construct a water spray booth

Before starting work on the equipment of a spray booth in Yekaterinburg, it is necessary to sketch out sketches schematically, in which you will see a clear idea of which basic elements the main structure consists of.

In general, the spray booth is a sealed box equipped with supply and exhaust ventilation. To create such a ventilation system, electric motors are used. The main part of the equipment includes a heating element, which allows you to maintain a high temperature throughout the entire painting process.

The camera must be equipped with lighting devices that allow obtaining uniform illumination throughout the entire area of the box.

For a small amount of work, a private garage can be used as a box. If there is none, you can organize a small building, which, of course, will entail additional financial costs.

Manufacturing

After designing a spray booth with a water curtain, the next step is the technical calculations. They must be carried out with scrupulous accuracy, as incorrect calculations can lead to defective equipment functioning.

An approximate diagram of the camera arrangement is as follows:

Door installation. They must be sealed and insulated.
The floor structure consists of an opening and a pipe that extends outward for air outflow.
The walls are insulated and sheathed with corrugated board.
The air exchange system includes metal pipes and two electric motors.
Insulated ceiling, made of corrugated board. A metal grill is installed in the ceiling for air flow.
Air purification is carried out thanks to a three-level filtration system.
Lighting is provided by ceiling and side lights.

A water heat curtain is one of the types of climatic equipment designed to maintain a certain temperature in a room by preventing warm air from leaking outside and cutting off cold outside air. This is a kind of thermal barrier that separates the room and the outer space with a flat stream of air, which is supplied under pressure.

The equipment creating a thermal barrier is intended for installation in the plane of a door or gateway in places with a large flow of people: in industrial workshops, public and residential buildings, shopping centers, warehouses, restaurants.

How a water heating system works

The principle of operation is quite simple: a radial fan directs an air flow to the opening - a kind of barrier through which warm air cannot leave the room, and cold air cannot penetrate inside.

The fan turbine is located along the entire device - this ensures an efficient and uniform supply of hot air that is pumped through the housing. The air movement pattern is as follows: cold air is taken from the floor, blown through the heating circuit and discharged in a hot stream parallel to the plane of the door or gate.

The motor is attached to the side. If the length of the turbine exceeds 0.8 m, then the engine is located in the central part, and additional small turbines are installed on the sides.

The cut-off curtain heats up as the air passes through the hot water coil. The water curtain requires central heating or a hot water network to operate.

The fully assembled design looks like this:

heat exchange mechanism;
control system (electronic);
fan;
frame;
guide blinds;
brackets;
side covers and covers.

Classification

The water heat curtain can be presented in various models designed for use in buildings with various conditions. Equipment classification is carried out according to various characteristics, including:

by purpose: general, for car washes;
by air consumption: small, medium, large;
by location: vertical, horizontal;
by geometric parameters: by the cross-section of the body - round, elliptical, rectangular, others; according to the structure of the nozzle - semicircular, straight.

Control

The water curtains are controlled by two switches, which can be mechanical or electrified.

The fan - which can be two-speed - and the heating elements are switched separately. The control system can be equipped with additional 2 (3) step heating power regulators. If the fan is two-speed, then its speed is also controlled by the remote control.

If a thermostat is installed, the equipment can be turned off automatically when the set temperature is reached.

The control panel, depending on the model, has varieties:

built-in - for small curtains that are installed above door or window openings in small rooms;
wired - in large rooms where it is difficult to control the built-in button, and the remote control can be located in a convenient place.

In warehouses and hangars, limit switches are used, which bring the system into operation only if the door or gate is open.

Unique advantages of the system

Water curtains have such design features that give them a number of advantages over electric heating devices:

Less energy consumption with equal heat dissipation. Cost savings can be up to 30%.
Possibility of installation in case of technical difficulties: insufficient power supply, high opening height (up to 12 meters).
Convenient maintenance due to the simplicity of the design.
Maintaining a stable temperature in the room and equalizing the temperature difference in the ceiling area and at the level of human height - this makes it more comfortable for people to be in the room and creates favorable conditions for storing any goods.
Neutralization of drafts, which leads to a decrease in the risk of colds.
Protection against the ingress of insects, small animals, dust into the building.
Possibility to use it as an air conditioner if you turn off the coolant circulation system.

The water curtain creates additional conveniences at car service stations, car washes, checkpoints and catering points, as it keeps the front door open at all times. In addition, it not only creates insulating protection, but also bears the function of a heater in the entrance to the warehouse.

The scope of its application depends on the functionality of the equipment: from air shielding of warehouses and hangars to preserving the interior of an office or shopping center from street dust.

Selection of a water heat curtain

Water curtains are needed, first of all, for air insulation of the interior of the room from the outside air. Performance, that is, efficiency, is the main characteristic of the equipment.

Other criteria are also important, which must be paid attention to when choosing a particular model:

type of premises;
is there a vestibule;
what are the usual weather conditions;
for what purpose the veil is acquired;
the desired type of installation;
control method;
dimensions (length) of the device required for high-quality overlap of the opening;
how much power is needed - this factor is most important if it is necessary to heat the room;
performance affecting air flow rate and unit height.

Heat curtain market

The most famous companies on the Russian market are:

Ballu (international holding) - products with minimum energy consumption. Among the models: horizontal BHC-H20-W45, BHC-H10-W18; vertical: Stella BHC-D25-W45, StellaBHC-D20-W35.
"Frico" (Sweden) - excellent design, excellent quality, versatility, but high cost. Model options: AR3515W, ADCSV25WL.
Tropic Line (domestic brand) - functional and efficient equipment at reasonable prices. However, only a few models (for example, X432W, X540W) are industrial water devices, the rest are household ones.
"Teplomash" (Russian manufacturer) - products are reliable, easy to use, affordable.

Serial Russian models "Teplomash"

As an example, we can take a closer look at the thermal power of the serial models of the Russian manufacturer - Teplomash:

... Shown here are the 100 series (opening: 1–2.5 m), KEV - P114E and P115E - with ceramic heaters with PTC self-regulation effect and temperature controllers.
Medium power. In this model range you can see the series: 200 (opening: 2–2.5 m); 300 (3–3.5m) and 300 ceiling series (recessed into false ceilings).
Interior. The 600 Series is available in elegant vertical columns and horizontal elliptical or segmented backlit versions.
Industrial thermal. Series 400 (opening: 3-5 m); series 500 (up to 6 m).

Heavy-duty structures - 700 series water curtain for openings up to 12 meters high. Usually made to order for special equipment (hangars for aircraft and helicopters).

Installation of models of the indicated series can be both vertical and horizontal - on the side of the door or gate. If necessary, can be installed on both sides of the opening.

In all designs, the casing provides a degree of protection - IP-21 (against vertical drops and large particles). If high humidity prevails in the room, IP-54 degree of protection can be provided on request (for some models).

Installation

Installation of a water heat curtain is laborious and requires the involvement of a specialized company - this will provide warranty service and subsequent maintenance.

The costs required for the installation of the equipment are fully paid off during operation due to the high power, efficient operation and low maintenance overhead.

There are 3 ways to position the system:

Horizontal installation - above the opening of a door or gate.
Vertical installation - on the side of the entrance opening.
Concealed installation - placement behind the suspended ceiling elements of the built-in unit with a cut-off flow outlet through the air supply grilles.

The height of vertical water heating curtains should be at least ¾ of the height of the heated opening.

Horizontal curtains should cover the entire width of the opening. Failure to comply with this rule will result in a failure in the air barrier.

Only the standard brackets recommended by the manufacturer are allowed to mount the system. The distance from the surface (in case of horizontal installation - from the ceiling, in case of vertical installation - from the wall) must be at least 0.3 m. Otherwise, the air intake of the equipment will be difficult, which will lead to a decrease in performance.

The equipment is connected to the central heating or hot water supply system using quick-release parts. If necessary, due to the type of insulated room, a pump is installed that enhances air circulation to enhance heat transfer.

Due to the generation of an air insulating barrier, water curtains create a special microclimate in premises for various purposes: from offices to warehouses and hangars. Such structures require energy consumption, but the overall energy consumption is reduced by protecting the building from chilling out. Water curtains can be considered an optimized energy source, working by circulating hot water in the general heating system.

. on the organization of the supply of painted products, ─ to dead-ends and checkpoints. For individual production, dead-end spraying booths of periodic action are more often used, and for large-scale production, walk-through spraying booths.

. paint booths can be open and closed (open and closed). Closed spray booths provide complete isolation of the work area from the surrounding area. This allows, due to the coordinated operation of the supply and exhaust ventilation, to maintain a pressure inside the chamber that is different from atmospheric, thereby preventing uncontrolled emission of contaminants. The body of an open spray booth forms a partially enclosed space. The number of 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 products to be painted.

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

Chambers with a water curtain in regulatory documents

How important, and often necessary, a spray booth with hydraulic filters or a spray booth with a water curtain is stated in a number of current regulatory documents.

“The air sucked out of the painting chambers, the cabins of the floor grilles is cleaned from the resulting aerosol of the paint and varnish material. Cleaning should be carried out, as a rule, by the "wet" method in hydro-filters. " This provision contains “Sanitary Rules for Painting with Hand Sprayers. Sanitary and hygienic characteristics of working conditions " .

Resolution of the Ministry of Labor of the Russian Federation of 05/10/2001 No. 37 "On the approval of the Interindustry rules on labor protection during painting works" even more categorical. Clause 3.52 .: "Exhaust air from the premises for work with paintwork materials, local ventilation systems and local suction must be cleaned from paintwork aerosols by the" wet "method in hydro filters."

Not only the sanitary and hygienic aspect is important, but also the fire safety requirements. "PPBO-109-92. Fire safety rules for railway transport " : “Painting works by spraying paint and varnish materials should be carried out in painting booths made of non-combustible materials and equipped with hydro filters. It is not allowed to operate the local suction system of painting cabinets, chambers and booths without hydraulic filters or other effective devices for capturing aerosols of combustible paints and varnishes. "

Color is very important

Painting booths are a relatively young type of equipment, in contrast to paints or varnish-and-paint materials (LKM), which mankind has been using for more than tens of thousands of years.

At least, the oldest of the rock paintings are of this age, for the application of which they used mineral powders, charcoal, lime, clay, and later animal fats, the secret of the glands of living beings and other biomaterials. The chemical industry has expanded 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) played with all the colors of the rainbow. It happened yet. and because color, being an integral part of design, has become one of the most important tools for promoting many products, incl. industrial products. In addition, the thin layer of paint has become very important economically, protecting millions of tons of steel products and structures from corrosion.

How important color is, and therefore painting equipment in general and spray 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 painting are one of the main trump cards in the competition, and the functionality of the spray booths largely determines the economic efficiency of production.

Prerequisites for the appearance of spray booths

formed in the second half of the 19th century... In 1887, a spray paint method was invented in the United States. (This, by the way, stimulated the appearance of paintwork materials with unprecedented properties, for example, quick-drying). Furniture manufacturers were the first to adopt the new technology ... But soon, and on a much larger scale, it began to be used in the rapidly gaining momentum of the automotive industry.

The interest in spray painting on the part of many industries has given a powerful impetus to the development of enterprises producing such devices. But at the same time, he clearly set before them the task of providing acceptable working conditions for the personnel operating them. The answer to these challenges was painting chambers, with the help of which it was possible to localize the influence of paint fragments not fixed on the painted surface ─ the so-called. "Colorful fog". Mists, as a rule, are called aerosols, the dispersed phase of which is represented by liquid droplets ... Of course, the contaminants accompanying the staining process, often very toxic, are not limited to fogs, ─ suffice it to recall such a component of them as solvent vapors.

Already at the beginning of the 20th century, tools such as an orderly air circulation system and air-purifying filters were involved in the implementation of an innovative technological concept for that time. As much as they look like modern spray booths, captured in photographs of the first half of the 20th century, they have changed a lot. Because as a result of scientific and technological progress, dry and hydraulic filters, fans, pumps, equipment for applying paintwork materials and paintwork materials themselves have changed (just remember about powder coatings, for which powder paint booths are used).

The range of tasks solved with the help of spray booths has expanded. As in the beginning of their existence, they help to minimize the harmful effects of paints and varnishes on the health of workers , only today against the background of stricter and more detailed regulations of national legislation in the field of labor protection. To this was added another important task, which at the beginning of the 20th century was not yet so acute, ─ reducing the burden on the environment .

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

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

How any spray booth works is to create a directed air flow... Outside air enters the work area. The quality of staining will be the higher, the better it is prepared, ─ it is cleaned of solid inclusions with the help of filters, has the required temperature and humidity. Already in "waste" form, contaminated in the working area as a result of contact with paintwork materials, it is cleaned by exhaust ventilation filters and discharged into the environment.

If some of this work is done by hydro filters, such devices are called water spray booths or water curtain booths. “Part of the job” ─ because the presence of hydrofilters does not preclude the use of dry filters working with them, usually located in front of the exhaust fan of the final fine filters.

Hydrofilters

Since the basis for the allocation of spray booths with a water curtain, in a separate class of equipment, was the use of hydrofilters, they (hydrofilters) have earned the full right to be presented first when considering the device of such chambers.

The term " hydrofilter »In this case means an air filter that cleans the air using water as a filter material. The disclaimer "in this case" is due to the fact that sometimes hydraulic filters are called hydraulic filters, that is, filters used to purify fluids in hydraulic systems.

The use of hydro-air filters is not a spray booth monopoly. They are, for example, installed in ventilation systems for air cooling, protection against sparks, removal of soot, soot, grease, and removal of extraneous odors.

Common to all hydrofilters ─ the purification of polluted air occurs when it interacts with water. Depending on the design, screen (cascade), nozzle and nozzleless hydraulic filters are distinguished. They differ in the principle of supplying air-purifying water and, as a result, in the peculiarities of their work.

In screen hydro filters, water curtains are created using overflow water distribution devices and shields. In spray nozzles, nozzles are used to form water curtains.

Pumping and non-pumping bubbling-vortex hydrofilters are also used, in which the air is purified as a result of its active mixing with water. Their name comes from the French barbotage - stirring. The principle of operation is the passing of gas or vapor (in our case, air) through a layer of liquid (in our case, water).

In a screen hydrofilter, an air flow containing particles of paintwork materials and solvent vapors is supplied to a screen covered with a continuous layer of water flowing down it, the circulation of which is ensured by the operation of the pump. Having collided with water, large particles lose their speed and together with it flow down into the bath located under the screen. Contaminants that have overcome this barrier are removed when the air flow passes through the water curtains located behind the screen. A droplet separator that can “handle” vertical and cross currents helps to make the air cleaner.

Side curtains can be installed along with front curtains. An active water floor (or an active water sump) - a bathtub covered with a grate, possibly buried in the concrete floor of the workshop - provides more efficient trapping of the ink mist.

In nozzle hydro filters, water is sprayed using nozzles. Typically screwed or tangential with a hole diameter of a few mm.

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

A sheet steel or plastic shield installed between the nozzle rows helps to create a directed air flow, preventing it from entering between the water torches.

The flow rate of water depends on the speed of its flow along the inclined shields or screen, 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 disposal of especially polluted waters, its supply has to be periodically renewed. The sludge of the spray booths with a water curtain is accumulated by a special water purification system from paint and varnish waste.

In order to prevent water constantly in motion from foaming, antifoam additives are added to it.

The case is “classic” and not quite

An obligatory attribute of a spray booth is a body. It is not always a "classic" enclosure with a floor, walls and a roof. It can consist of only one front wall. There are tubeless technologies for applying paintwork materials, used, for example, for painting large-format products. And in many of these devices, the air is purified using hydro filters. They can have different designs. For example, tubeless installations with bottom suction, consisting of a hydraulic filter, an exhaust ventilation system and a pumping unit. For painting vertical surfaces, lifting platforms equipped with a hydraulic filter are used, ─ air contaminated with paintwork materials is drawn into the gap formed by the surface to be painted and the wall of the hydraulic filter of such a platform.

Side walls and a roof help to create a directional air flow and prevent contaminants from entering the workspace from spray booths located nearby.

Spray booth housings 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 an experience of using plastic with a release coating, with a thickness of 10 mm or more. The advantages of this solution are that paint residues are less likely to adhere to the camera surfaces and are easier to remove.

The dimensions of the spray booths are determined by the organization of work and the size of the products for which they are intended to be painted. Organization of work ─ is where, ─ inside or outside the chamber, ─ is the workplace located, 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 provides the required direction of movement and the uniformity of the flow of exhaust air to be cleaned ─ from the working area to the hydraulic filter.

Usually, centrifugal and axial fans of medium and low pressure are used, 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 "revolving" fans, it is necessary to prevent noise and vibration impact on the camera body.

In an open spray booth, all or most of the clean air enters through open openings directly from the workshop, and its lack in the room is compensated by the workshop supply 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 booth is in operation can be used. This is true for spray booths located in small spaces.

Trends in the development of painting technologies used in mechanical engineering, woodworking, the production of building and other metal structures ─ wherever spray booths with water curtains are used ─ are determined by the progressive tightening of requirements for environmental protection 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, improving the quality of work.

They can be met 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 have to change. More in content than in form. However, this is exactly what they have been doing for many decades.

In most cases, the search for information about the spray booth device begins when the need arises in a professional room, i.e. when a person is already working with car enamels, but the current state of affairs does not suit him. In this case, the principle of operation of ventilation and air purification is generally clear, but to implement the idea with your own hands, specific drawings and diagrams are required. There are countless nuances and traps in this business, but the main thing is to understand the processes of drying and painting, knowledge of the basic requirements for temperature conditions.

In no case should you limit yourself to ready-made solutions: having considered several typical projects, you can select elements that cannot be discarded, add your own details to the project, etc. funds. Some elements will probably have to be abandoned, but with an understanding of the basic processes, there is always an opportunity to save money.

Typical designs and operating principle of the camera

The main requirement for the chamber is clean air of the required temperature. The idea is simple, but it is quite problematic to achieve its implementation, given the commercial nature of the design. The first thing to consider when designing is the required service rate. The design should provide for the development of the business, which primarily refers to the ability to supplement the premises with your own color scheme (or a separate workshop) and install more powerful equipment. The photo of this camera shows that the painters have the ability to move on lifts, but first of all, you should pay attention to the competent combination of lamps and ventilation grilles.

It is difficult to attach a workshop to the camera or to allocate a room for tinting, but it can be equally difficult to transfer equipment to your own energy generators. The last condition directly relates to the wiring, but a place for the welding machine (compressor) may also be required. In terms of the volume of painting, two types of spray booth are distinguished:

Industrial - in the presence or in theory, rails and devices for lifting the machine and automation of movement, hydraulic baskets and powerful welding machines.
Commercial - a box made of sheet iron or a brick block, starting equipment from a standard power grid (in a rare case, welding power plants are used), the size rarely leaves the 5x10m limits sufficient for painting passenger cars.

Painting procedures should be carried out in an atmosphere completely free of dust and insects. Novice painters have to clean the room from dust with their own hands using rags and an artificial water curtain. However, the design of the chamber should include three stages of ventilation, the implementation of which is impossible without automation:

Initial air intake, filtration and warming up the room to room temperature.
Painting stage - continuous air injection and warming up to 25-30 ˚C.
Drying - circulation of air heated to 30-60 ˚C.

Air heating, ventilation and insulation are parts of the equation that directly affect each other. It is impossible to change one of these elements without changing the other two. Inadequate insulation during the drying phase will require the elimination of continuously forming condensation. Therefore, it is necessary to calculate ventilation for both painting stages indicated in this diagram.

Filtration and distribution of air flows

In a correct spray booth, a continuous complete air renewal must be carried out. Therefore, it is more logical to place the hood at the bottom, and the supply fan at the top. It is incorrect to place the air outlet holes only above the painting area, however, using a correctly oriented supply plenum, the principle of which is shown in this drawing, will make it possible to better manage the space.

An adjustable gas burner can be used to heat the air, which is connected during the drying phase. The heating element is located after the filter and fan, sometimes outside the pipe. In any case, the design of the paint room must provide for reliable insulation of the heater from explosive gases, therefore, the air through the heater must move strictly in one direction, and through the attic space (pipes, plenums) must be blown at such a speed to prevent reverse movement. When the fan is turned off, the heater must stop functioning immediately. The location of the filter over the main area of the ceiling assumes a uniform distribution of air over the area, however, with a weak fan, it may simply not be enough - a preliminary calculation is important to determine the area of the grilles (plenums) and their location without the formation of turbulence zones.

The incoming air is cleaned by several filters, while the coarse filter should be located before the fan, and the fine filter should be located directly at the border of the box. As the latter, cotton filters are often used, which are sheet (roll) material placed on top of the ventilation grill. The longest service life is possessed by pocket (mesh) filters that comply with DIN 53438 (pre-filtration), European standard EN779 and DIN EN 779 (internal filter class F5). In the above project drawing, the primary filter is designated by number 2, and the air intake is designated by number 1.

Drying mode

Safety is the main condition when developing and assembling a spray booth structure with your own hands. Therefore, ventilation performs two functions at once: the elimination of toxic gases and the removal of dust from the air. Immediately after the end of the painting procedure, the maximum release of solvent vapors occurs. All types of enamels have their own distribution along the time scale of evaporation intensity, but in general, complete air cleaning takes only 10-20 minutes (otherwise a matte layer will form on the enamel surface).

After the end of the painting procedure, the chamber is ventilated for some time in a standard mode, but after that there is no direct need for clean air. In view of this fact and the cost of heating the room, an air recirculation system is used during drying, which saves 40-50% of energy. To do this, supply and exhaust ventilation are connected by a valve that allows 70-85% of the air to pass back. The principle of operation is demonstrated by this drawing, while it must be borne in mind that an update of 15-20% of the flow at each cycle is necessary even at the time of the end of drying.

Spray booth materials

A frequent solution to the issue is re-equipment into a chamber of a household car, but in this version it is difficult to organize the correct exhaust ventilation. Even at the design stage, the device of a box for painting should provide for an underground hood (second floor, trenches) and an attic space for organizing air distribution. Having provided for such an opportunity when laying a concrete base, in the future, you can easily transform the hood and inflow with your own hands already outside the room for painting work.

If the ceiling ventilation grille occupies less than 2/3 of the ceiling, then the ceiling must necessarily have slopes at the edges to eliminate dead zones. Most often, these slopes are combined with side lights. The exhaust ventilation must be less powerful, so the grille can occupy the entire floor or most of it, as can be seen in the photo of this spray booth.

Most amateurs have to be equal to the standard dimensions of the garage "6 × 4", but it should be noted that 20-40 cm will have to be "cut off" from the ceiling immediately in order to arrange supply ventilation. The walls are sheathed with sheet iron, mineral wool or other non-combustible insulation is laid in the gap between the wall and the galvanized steel (at least mineral wool - 60 cm thick). If you have the original brickwork in the project, you can limit yourself to PVC panels, however, it will be correct to use galvanized sheets offered in the device of any professional paint booths.

Painting box - a room equipped for painting cars. One of the key factors affecting the usability of the spray booth is the ventilation system.
The size of the hood directly depends on the size of the paint spraying

In the process of painting a car, fumes, toxic to the human body, are released from the paint and the solvent added to it, a painting fog is formed, which impairs visibility and settles on the body of the vehicle. The supply and exhaust air replaces the exhaust air with fresh air, providing optimal conditions for painting the machine.

In this article, you will learn what a spray booth hood is, what filters it comes with and how to calculate ventilation yourself. We will also provide instructions, following which you will be able to equip the hood in the spray booth with your own hands.

Types of ventilation systems and their comparison

Painting a car is work involving the use of toxic substances, the application technology of which requires compliance with the temperature regime and maintaining the cleanliness of the air at a given level. The hood is not only for the safety of the painter, but also for the quality of the painting process and the polymerization of the applied coating.

The paint garage hood must meet the following requirements:

Air supply temperature during painting - 20-30 degrees, air temperature during coating drying - 50-85 degrees;
The speed of the air flow is 1.3-1.5 m / s (at excessive speed, the paint sprayed with a spray gun is carried away by the air flow, which interferes with the work);
The frequency of air renewal in the box is 5-150 volumes / hour (to accurately determine the required frequency, the ventilation of the production room is calculated);
The air pressure in the box is 20-30 kPa higher than the natural atmospheric pressure of the environment;
The flow injected into the chamber is clean, without dust and mechanical impurities (an air filter is used for cleaning);
Air flow movement - from top to bottom, or with minimal vertical deviation.

Based on the type of ventilation, spray booths are classified into two groups:

Single-engine;
Twin-engine.

A single-engine ventilation chamber that forcibly blows fresh air into the box, while exhaust air is pumped out naturally due to the pressure difference inside and outside the chamber. The supply holes are located in the upper part of the room, the air flow entering the box settles the paint mist downwards, then the vapors enter the hood nozzle and are discharged outside.

In twin-engine boxes, ventilation provides forced supply and intake of air from the chamber, which provides effective circulation and a high frequency of air exchange.

It is rational to choose a specific type of ventilation based on the size of the box and the amount of work carried out in it. If the chamber is operated during a whole working day, and dozens of cars pass through it, it makes sense to install a twin-engine ventilation. In small-sized boxes, it is advisable to use single-engine systems - there will be enough productivity, in addition, you will save on the initial cost of equipment and subsequent maintenance.

Supply and exhaust ventilation

A type of twin-engine systems is a supply and exhaust hood that operates in 3 operating modes:

Circulation inside the chamber - air is pumped out of the box, passes through the filter layer and is pumped back into the room. It is used when cleaning the chamber before starting painting work;
External supply - the supply compressor takes air from the outside of the box, filters it and passes it through the heat generator, where the air is given the required temperature. The stream is fed into the chamber, after which the exhaust compressor pumps the exhaust air out. It is used in the process of painting a car to eliminate paint fog;
Recirculation with heating - the air taken from the chamber is filtered, passed through a heat generator with heating to a predetermined temperature and fed back to the box. It is used to maintain the temperature regime when drying the surface of the body after painting.

Supply and exhaust ventilation requires precise positioning of the inlet and outlet ducts, since if the ducts are not correctly located in the box, "blind zones" are formed in which there is no air circulation. Suspended paint particles remain in them - paint fog, which subsequently settle on the surface of the body, which negatively affects the quality of the final coating.

The calculation of the supply and exhaust ventilation consists in determining the volume of air supply that provides the rate of air exchange required to reduce the concentration of toxic paint vapors (MPC) in the room to the standard level.

Industrial spray booth

The amount of paint evaporation depends on the type of added solvent composition:

The calculation of supply ventilation by the rate of air exchange is carried out according to the formula K = d* S * H, wherein:

d is the required rate of air exchange in the room;
S is the area of the box (m2);
H - box height (m).

The current regulatory documents do not provide standards for the frequency of air exchange in the spray booths, however, experts recommend calculating the supply ventilation of the room based on the frequency of 5 (with partial painting) and 150 (with complete repainting of the body).

An example of calculating air exchange in a spray booth with an area of 4 * 7 m and a height of 4 m according to the multiplicity formula (taking into account the maximum value - 100) is as follows:

K = 150 * 28 * 4 = 16800 m 3 / hour;

Manufacturers of spray booths take into account an air supply of 25-30%. Factory chambers of the same size have an air exchange rate of 20-25 thousand m 3 / hour (800 m 3 / hour for each m 2 of the boxing area).

The calculation of air exchange, which ensures a decrease in the MPC to the norm, is carried out according to the formula: , wherein :

W - the amount of harmful fumes from the paint for 1 hour of operation (mg / h);
Kv - maximum permissible concentration of vapor in the air inside the box (mg / m3);
Kp - MPC of vapor in the supply flow (with air intake outside the chamber = 0).

Harmful fumes for 1 hour of work are determined by the formula: W = 1 * Kv * V, where:

1 - constant;
Kv - normative MPC of the material (mg / m3 per hour);
V is the volume of the box.

Ventilation is carried out according to the formula: U = d * V, where d is the rate of air exchange, V is the volume of the box. The amount of air pumped out and injected into the chamber is always the same.

After determining the air exchange, an aerodynamic calculation of the ventilation system is carried out, during which the required cross-section of the air ducts and the air flow rate are calculated, taking into account the resistance of the filter materials.

Filters for spray booth

The absence of dust and mechanical particles in the air supplied to the box is a factor that determines the suitability of the camera for use, since the dirt that gets on the car body during the painting process cancels out all the efforts of the painter.

Depending on the filtering method, the boxes are classified into two groups:

Dry spray booths equipped with roll or panel filters for coarse and fine cleaning;
Spray booth with water curtain - when supplied, the air flow passes through a water cascade or a reservoir with an irrigation system. Water filtration in them replaces the primary coarse filter.

Filters for spray booths are classified according to their functionality into:

Coarse cleaning - mounted on the external air duct of the supply ventilation, cleans the flow from large mechanical particles;
Fine cleaning - installed on the ceiling of the box or on the internal supply air duct, cleans the air from dust;
Floor filter for spray booth - installed on the exhaust fan, cleans the pumped out air from toxic paint fumes.

Filters for painting chambers are consumables that get dirty during operation, as a result of which their throughput and the quality of cleaning are reduced. When servicing the box, consumables are replaced, the frequency depends on the filter material:

Camera carton filters are changed every 2 weeks;
Fiberglass - once every 40 days;
Ceiling EU5 standard - every 1000 hours;
Floor standing - every 150 hours.

Supply and exhaust ventilation with your own hands

The capacity of the hood is selected separately, depending on the size of the spray booth

The hood in the spray booth is equipped with its own hands upon completion of the installation of the boxing box. The first stage of installation is to create a raised subfloor and place an air intake duct in it, through which air is discharged to the outside of the chamber.

The raised floor is equipped by pouring concrete into the formwork, in which grooves for laying the air ducts are provided, or formed on an existing floor. With this approach, a grating floor with a height of 20-40 cm is welded from reinforcing rods, an air intake is laid inside the grating and connected to an exhaust compressor.

The supply duct box is located on the ceiling of the chamber, a compressor is connected to it, coupled with a heat generator or electric heating elements, due to which the flow entering the chamber is heated to the required temperature.

To prevent "blind spots" along the side contours of the chamber, 8 air ducts (2 for each wall) are placed from the supply duct along the perimeter of the box walls, providing horizontal air supply.

Hood safety

The spray booth is a room with a high level of fire hazard. For its equipment, it is permissible to use exclusively explosion-proof ventilation units.

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The safe operation of the box is achieved due to the following factors:

The heat exchanger that heats the supply air is equipped with a safety thermostat;
The thermal insulation of the chamber is made of fire-resistant materials - mineral or basalt wool;
The box is completed with an autonomous fire extinguishing system;
Heating heating elements of ventilation are grounded on
Air ducts are equipped with explosion-proof air shut-off valves and check valves;
In places where fire-hazardous paint vapors accumulate (particles settle in the lower part of the box), additional air intakes are installed if necessary.