We select the compressor for the spray gun

Painting cars is a rather complicated production process, the key role in ensuring good results is played by reliable tool operation. In a small garage and in a huge service station, almost identical spray guns can be used to work on the hulls and other assembly elements. However, different goals, the volume of operations produced, their nature impose the inevitable differences in the used blowers, strapping and other equipment. Therefore, choose a compressor for painting - a task that needs to be addressed very carefully.

What are the compressors

Spray guns, sandblasting machines, equipment for plastering and applying fine mixtures put forward certain requirements for the compressed air injection system. The pressure and pumping characteristics (for one device) are insufficient for the application of industrial units. At the same time, the required parametrics are serious enough to ensure that it was necessary to carefully select the compressor for the spray gun.

Today in paint shops, garages and workshops are widely used:

• screw devices;
• piston models of oil and oil-free type;
• constructions with coaxial and belt drive.

Each type of equipment has its own characteristics and disadvantages. And for everyone there is its own optimal scheme of application.

Oil-free piston compressor

Feature of piston oil-free models - full no lubrication in the system. Piston components and other construction details are made of special wear-resistant materials. Low mutual friction ensures the durability of the compressor as a whole.Devices of this class are capable of:

• create pressure up to 10 atm;
• provide good performance;
• offer compact size and low weight.

However, the unit of oil-free type, which is needed for the spray gun, will make you put up with:

• high heat generation;
• short term of continuous work;
• increased noise level.

Important! Oil-free models due to relatively high friction losses are characterized by low efficiency of the system as a whole.

Piston Oil Compressor

In a piston oil compressor, all moving parts are covered with a lubricant to reduce friction losses. This class of devices different durability. The oil is in the crankcase of the piston group. As a result of splashing and feeding gears it falls on all the details of the design. This technical solution has several advantages:

• friction losses are low, which increases the efficiency of the system as a whole;
• heat generation is insignificant;
• equipment can operate for a relatively long time.

Among the shortcomings, the need for maintenance can be noted: the compressor feeding the sprayer periodically needs topping up and changing the oil. However, this trifle did not prevent devices of this type to gain enormous popularity, primarily in small workshops and garages.

Screw compressor

Screw type supercharger - complex and technological design. It is quite expensive, difficult to regulate. If damaged, the rotors can not be repaired. When replacing worn bearings and other parts, it is recommended to contact specialists for work and reconfiguration of the device. \

Despite the listed shortcomings, screw models are very popular where the compressor spray gun used almost continuously. They are able to:

• supply large amounts of air under high pressure;
• work continuously for tens of hours;
• show the highest efficiency;
• fine-tune to the desired mode of operation through electronic control systems and regulation.

The screw-type compressor emits little heat, does not require periodic maintenance. Devices of this class are very popular in the paint shops and the service station. But in a small workshop or garage, they will take up too much space and load the wiring.

Coaxial and belt driven systems

Compressors coaxial drive familiar to all. In them, the shaft of the electric or internal combustion engine of the engine is connected directly to the piston unit. Such devices are distinguished:

• high engine speed;
• significant number of strokes per minute.

Important! As a result of the operation of the system, heat is generated, the engine suffers load surges due to the need to supply air with variable pressure. O-rings are erased in the piston group, which necessitates their periodic replacement.

The compressor looks much more attractive in terms of technological characteristics. belt driven. In it, the shafts of the piston group and the engine are not directly connected. The transmission of torque occurs through the pulleys and belt drive. The diameter of the wheel of the engine is smaller than the corresponding part on the piston shaft.

As a result of this technical solution is achieved:

• reduced number of strokes per minute;
• a sharp decrease in load spikes on the motor shaft;
• increase in time between replacements of sealing rings, other elements with a limited service life;
• system efficiency increase;
• increase in pumping without increasing engine power.

The main disadvantage of compressors with a belt drive is increased noise. This is easily explained: the engine is almost always running at maximum speed. However, this drawback does not seem important, given that the compressors with a belt drive are characterized by high stability, load capacity, overall reliability.

Where specific types of compressors are used

Based on the characteristics of individual types of compressors, their average statistical areas of use can be easily determined.

1. For small, one-time workFor example, painting a dismantled door or treating a small surface would be suitable for an oil-free piston compressor. His resource of continuous work is enough for the desired operation. In addition, the use of the receiver and other strapping (to be discussed later) will allow you to work comfortably and achieve excellent results.
   

2. For full-color paintingFor example, one car will need an oil piston compressor. The receiver is an essential part of the air supply system.Which compressor model to give preference (with a coaxial or belt drive) depends on the master's needs, the time of using the equipment and the ability to conduct periodic maintenance.
3. Large workshop where held average amount of paint work, and compressed air is used for pneumatic tools, can not do without a powerful piston oil compressor with a belt drive or a screw model. Such equipment, complete with a system of receivers, is able to satisfy large needs for compressed air.
4. For the workshop where it is held wide range of car operations (painting, removing rust with sandblasting machines, applying protective coatings, using pneumatic tools) you will definitely need a screw compressor of an industrial type with belt drive. Only such equipment in conjunction with compensator receivers is able to ensure uninterrupted operation during the working day or around the clock.

How to equip a workstation

The choice of the compressor is made, first of all, according to the characteristics of spray guns and other pneumatic equipment used.For this purpose, the nominal limit of the pressure indicator is determined from technical data sheets, as well as the requirements for pumping. Based on these figures, the choice of a supercharger is made.

Important! For piston-type equipment, it is necessary to lay a 15% margin for both indicators.

However, the fact that the compressor fully satisfies the needs of the tool used does not mean that the device will ensure comfortable operation. First of all, it is connected with the impossibility of functioning of any type of equipment in a continuous mode. This is especially true for reciprocating compressors.

Why do you need a receiver, and how to choose its volume

So that the air supply system does not force to put up with restrictions, a system of receivers is created. In the simplest case, it is large metal tankequipped with pressure switch. A reducer is installed at its outlet, which stabilizes the output pressure. The system works as follows:

• the compressor turns on and forces air into the receiver;
• when the pressure reaches the maximum configured relay, the indicator - the compressor power is turned off;
• during air extraction by the spray gun, the pressure in the receiver drops;
• when the pressure drops below the configured limit relay, the compressor starts.

Thus, the receiver allows you to automatically turn off the compressor to cool it. At the same time at the inlet of the spray gun remains sufficient pressure for high-quality work.

When creating a receiver, two rules should be followed:

• choose a cylinder that can withstand a pressure of at least 1.5-2 times greater than the maximum rate generated by the compressor;
• ensure receiver capacity of 33% of the nominal capacity of the supercharger.

How not to spoil the painting: removing impurities

Each type of compressor has its own characteristics of forming the air flow at the outlet. In particular, oil-free it contains moisture droplets. In oil piston - grease particles.The ingress of unnecessary impurities can disrupt the characteristics of the paint mixture and spoil the final result of the work. To prevent this from happening:

• in the compressed air supply system, at the receiver outlet or at the spray gun inlet water traps are installed;

• at the receiver inlet or outlet of the oil piston compressor mounted special oil traps.

Type of power supply of the main supercharger

The average user imagines a compressor as a device that plugs into a 220V outlet. However, an analysis of the market, on the condition of careful selection of equipment for specific needs, shows that it is more profitable to choose a supercharger for the existing power grid. Today on sale are offered:

• 220V compressorssingle phase network;
• devices with attractive features oriented to a 380V three-phase network;
• superchargers capable of operating with two types of power networks.

When choosing a compressor, it is convenient to focus on the existing power distribution structure.

Equipment options for various fields of activity

In numerous variations, sets of components for building an effective air supply system can get lost. Therefore it is worth giving a few simple recommendations, patterns of average decisions.

1. For domestic use in the periodic mode the piston oil compressor perfectly will approach. Today, there are many variants of ready-made stations on sale that supply air with pressure up to 8 bar. Such kits are equipped with a receiver with a volume of from 6 to 100 liters (it is recommended to choose at least 50 liters), able to work at a rate of 20 minutes every hour.
2. Compressor stations semi-professional class built on oil piston compressors with coaxial or belt driven, equipped with a receiver with a volume of at least 50 liters. They also cannot be operated non-stop, but the effective operating time is up to 40 minutes every hour.The average pressure maximum is up to 16 bar.
3. Equipment industrial (professional grade) has no clear gradation of parameters. As a typical feature, huge volumes of receivers can be noted - up to 1 cubic meter. Such stations can operate continuously, you can purchase equipment with characteristics that satisfy any needs.

For especially single, garage works the compressor station can be collected the hands. To do this, you will need to purchase moisture and oil separators, a gearbox, a pressure switch and find an empty gas cylinder in good condition. The main supercharger in the homemade station is the compressor from the refrigerator. This device belongs to the oil piston class.

After dismantling the refrigerator, the old oil is drained from the unit and modern synthetic is poured. After that, the output tube is connected to the receiver, and the power system is switched through a thermal switch. Mini compressor of this class is able to meet the minimum garage needs.

Conclusion

In the process of painting, the stability of the compressed air preparation system and its ability to provide the desired flow parameter is of great importance.One supercharger without strapping not able to meet the needs of the workshop or allow to paint the whole car, acting without interruption. However, carefully analyzing the needs, it is easy to find a set of equipment that will ensure a comfortable and convenient operation.