Compressor For Pneumatic Impact Wrench What You Need

Additional equipment. what to consider?

Buying just one compressor does not mean that the connection to the instrument will be properly set up, and the work will be done well. The technical organization of the process often involves the use of special hoses, adapters and clamps. As practice shows, even a lightweight pneumatic tool, when connected to a compressor, requires the use of clamps with suitable dimensions. Personal protective equipment should not be ignored either. If the compressor for the pneumatic tool will spray abrasive materials, then you must take care of protective headphones, gloves and goggles. To work with paints and varnishes, it is also recommended to purchase overalls that will provide protection against chemically hazardous substances.

What kind of compressor should you prefer??

Segmentation of compressor types according to design also helps to make the right choice for inexperienced users. Models that are marketed as automobiles are suitable for most household needs. from painting surfaces to inflating rubber mattresses. A piston unit, which is used by workers in workshops and ordinary car owners, can also be a win-win solution. If the question is about which compressor is needed for professional pneumatic tools, then you should pay attention to screw and belt models. Such devices usually have high power ratings and pressure levels.

How to choose a compressor for pneumatic tools?

The compressor is a must for most air tool models. Such equipment is used both in private households and in specialized workshops. There is also a separate category of industrial equipment, whose representatives also require the connection of compressors. The variety of pneumatic units makes it difficult to select additional components, however, provided the correct equipment is used, the user can count on a quality result in the process. The question of how to choose a compressor for a pneumatic tool, of course, primarily involves a mention of functionality, reliability and durability. But even compliance with these characteristics does not always provide the expected effect of using the tool.

Basic selection parameters

An experienced technician evaluates compressors according to three main characteristics, including pressure level, capacity and receiver volume. For the first criterion, the starting point is 6 bar. This is the minimum pressure that a compressor has at its disposal for a pneumatic tool designed to perform simple household operations. Models with a pressure level of 10-15 bar are also common. This equipment is capable of working with more demanding units, including those from the industrial sector.

Compressor capacity is expressed in liters of working mixture sprayed per minute. So, for small-scale painting activities, 10-50 l / min is enough. But this range can be extended to 500 l / min when it comes to the use of equipment in the workshop. The volume with which the compressor for pneumatic tools for household use works is on average 7-10 liters. Of course, there are more spacious receivers, but they are mostly used in highly specialized areas.

Compressor manufacturers

Almost every manufacturer of construction or industrial equipment contains compressors in the line for different purposes. If we talk about domestic companies working in this direction, then Caliber and Elitech come to the fore. The products of these brands may not always be able to compete with the best foreign models, but for the price it is the most profitable acquisition. However, the question of how to choose a compressor for pneumatic tools with a high level of quality should be solved with the help of foreign products. The assortment in this segment is quite wide, however, the brands Fubag, Metabo, Senco and others are the most trusted by specialists.

Dimensions and design features

In addition to technical and operational indicators, it is important to take into account characteristics such as mobility and size. For example, if you intend to work with a spray gun for painting a fence, then you should turn to lightweight and ergonomic devices. Even if they provide a minimum level of performance, it is more likely to be sufficient for simple operations. These models include, in particular, the coaxial compressor for pneumatic tools. The choice in this direction can be guided by oil-free equipment, which does not have a receiver at all, but wins in compactness. If you need a powerful and efficient compressor with a massive casing, then it is recommended to purchase models equipped with comfortable handles and wheels.

How to choose a compressor for car painting

expert of the category “Construction equipment”

A compressor for painting a car is a guarantee that the painting will be at the highest level. It helps to carry out this process easily and without problems, that is. with a correctly applied layer of paint and evenly sprayed paintwork.

Each compressor works on the principle of a pump, only it does not supply liquid, but air. Air compressed under pressure is accumulated in the receiver, and from there, through the connectors, it is supplied to the spray gun.

What is the most important compressor parameter for painting:
air flow or pressure?

How to choose a compressor for painting in order to achieve the best result and what parameters should be paid attention to?

It is believed that the pressure of a compressor determines its class: the higher it is, the better the unit. I guess, yes. Although there are pitfalls here, not every compressor has a constant, high pressure, only more expensive models of equipment of well-known brands can boast of this, and this is an expensive purchase and not everyone can afford, and the average recommended pressure in a pneumatic tool is 6-8 atmospheres. so chasing this parameter is not always necessary. But if your paint shop air supply system is designed for multiple connections. this parameter is considered a priority.

Our recommendation. pay more attention to the air consumption indicator. Here’s why: Compressed air determines the performance of a compressor. It is he who sets the mechanism into operation. For this reason, the amount of compressed air and its consumption play a special role in the selection of pneumatic tools and vice versa. Pneumatic tools have no such thing as power. It is called the air flow and is indicated in the data sheet. That is, the same paint sprayer may require 150 liters of compressed air, or maybe all 400. If you connect a compressor with a capacity of 200 liters per minute to the second option, then there is no point in starting work. there will be no painting, and the device itself can quickly come out out of service

The most common compressor problems

Air compressor for painting, like any other technique, can break. Sometimes this happens due to problems with electricity, sometimes due to factory design defects, due to overload and overheating of the mechanism during operation, etc.

I will give you two main problems. One of them concerns the incorrectly selected pneumatics. The other is partly due to the same reason, and partly due to factors that you are not even aware of.

First. breakdown due to incorrectly selected high-flow gun

All spray guns are divided into three groups:

• With HP high pressure technology. Pistols of this type require a pressure of 8-10 bar, but their air consumption is small. Such devices are considered obsolete, since a large loss of paint occurs due to the high pressure. But any compressors will suit them, even with a small capacity.
• HVLP pistols. This technology uses increased air consumption.
• With LVLP technology. This means: “a little pressure. some air. ” The most versatile, as even a low-power compressor will satisfy them.

Problems arise when attaching a gun that has HVLP technology that requires a lot of air. This technology is the most widespread, as the efficiency of painting increases up to 90-95%. But the air flow rate is a trap that many inexperienced users fall into. Be sure to read the need for air on the pistol. If it is 200 liters per minute, then the compressor must be selected with a capacity of at least 200, plus a margin of 30-40%. That is, the air blower should have a performance indicator of 250-300 liters per minute. Then he can easily pull out such a pistol.

If you missed such an important number, then the following happens when connecting: in order to supply a lot of air (to the maximum or even more), the compressor constantly turns on, because the pressure in the receiver is constantly dropping. Your device is trying to pump the right amount of air, working for wear. It turns out that the engine runs constantly, but the outlet pressure still “floats”. You start to stop work, pump up the pressure. And in vain. All the same, the required air flow will not work, since the compressor simply cannot provide the required performance. But the motor is working to the limit. It’s good if the automatics turn it off, but if not, there is a terrible wear of the piston group, and in the end, the mechanism breaks down.

The elimination of the problem is to select a different gun with a suitable air flow. If a breakdown occurs, replace the pistons, although this is already completely unnecessary money spending. They could have been avoided by carefully looking at and comparing two indicators before buying:

• compressor performance;
• gun air flow.

Ideally, the first should be 30-40% larger than the second.

The second reason. overheating of the compressor itself

By overheating of a compressor, I mean overheating of the windings of its electric motor. Again, if there is a thermal relay, this is very good. It will turn off the mechanism on its own, and the unit simply will not work. But if the situation repeats itself over and over again, then the relay itself will become unusable, then the working windings burn, solder and break. The engine needs repair. either a new motor, or winding the rotor and stator over a new one. Therefore, you definitely need to find out why overheating occurs. There may be several reasons:

• The most obvious one. your device is not powerful enough to compensate for the load. This situation arises, as I already described above, when connecting an incorrectly selected pneumatics (with a large air flow rate);
• Insufficient cooling. Inspect the cooling system. It is usually airy. There is a natural one. thanks to stiffening ribs on the cylinder heads, there is a forced one with a fan. The second is much more efficient, but the impeller can jam if not lubricated, clogged with dust and dirt. Lubricate, clean or after work blow out the compressor itself from dust.
• Insufficient engine oil. The rubbing parts (piston pair) feel increased resistance and begin to heat up. Cooling can’t handle the situation. Here the solution is simple. to carefully monitor the level of the filled oil. But if you overflow the recommended level, it can create the following problem;
• Too much oil. the pistons are operating in an overly viscous environment. This can also cause them to heat up;
• Poor mains voltage. The supply voltage is much higher than the norm (the norm is 220 Volts, deviations of 10% are allowed, but not more). Measure the voltage at the outlet. If more than 240 volts, install a voltage regulator.

How important is the type of compressor drive, and how it affects its operation

The choice of a compressor for painting a car is impossible without studying the features of the compressor drive. In modern units, 4 types of drives are used, but the most popular are:

• Straight
• Belt

With direct drive, the torque is directly transmitted to the crankshaft of the air-blowing part of the apparatus. In another case, with a belt type of drive, the torque is redirected from the driving pulley to the driven pulley using a belt.

Since the design of the drive is different, then their role in improving the operating parameters is also different. Professionals recommend using belt drive models, although they are more expensive.

Here are the main advantages of such units:

• High revs thanks to the direct transmission of torque. about 2800 rpm;
• Belt units are more resistant to overheating during long-term operation, since the structure has a large number of radiator sections to cool the air;
• The smaller diameter of the crankshaft drive pulley in the belt drive makes it easier to start the engine;
• And two and more cylinder engines are made of cast iron, which improves heat transfer and increases their resource and ability to withstand high temperatures.

That is, you work with a belt compressor for a long time, there is no overheating, and its resource is incomparably higher.

For household chores, it is quite possible to buy devices with a direct drive. They are not only cheaper, but also more compact in size. And their repair is much easier and inexpensive. But do not expect durability from such a device, as well as the ability to work for a long time.

Compressor types and their comparison

Before choosing a compressor for painting, I recommend that you decide for what purpose, and what type of painting you need it. Different types of painting require different technical parameters, which are determined by the class of the device.

Among the huge variety of compressors that are on the market today and are available for purchase and use in garages and professional service stations, there are three main types:

Household compressors (garage). These are relatively cheap units, piston and single-cylinder with a 20-25 liter receiver. They do an excellent job of minor painting and blowing jobs. The average air flow in such devices is 130 l / m. You cannot connect professional pneumatic equipment to them, but it is quite possible to paint a gate, fence or small parts slowly. They can also be used with efficiency when working with airbrushes, where more constant pressure is required from the compressor for even application of parts.
2. Semi-professional units. These are reliable and expensive units that can be used for more serious tasks. Two types can be distinguished here:

• Piston with a 50 l receiver, direct drive or two-cylinder, the average air flow rate of which ranges from 200 to 330 l / m and has a pressure of 8 atmospheres;
• Piston with a receiver of 100 l, single-cylinder with a belt drive, picking up a speed of 330 l / m and more, the pressure mark is kept within 10 atmospheres.

I advise you to use such units both in your home garage and for large-scale works. Without interruption, you can paint the whole side of the car. But such devices can also be overheated. When overloaded or operating for a long time, the piston compressor for painting a car can become very hot, which will lead to imminent damage. The first type overheats due to the fact that it has a direct motor drive, and the second, having an improved design, namely a belt drive, is equipped with one piston with an aluminum head, which also entails overheating and failure during prolonged operation.

Professional units. The most expensive and reliable units with sophisticated technological features. These are piston units with a receiver of 200 liters or more, with a belt drive, cast-iron engine heads, built-in filters for trapping oil and moisture, and an overheating protection system. The air flow in such devices can even be more than 1300 l / m, and the pressure is 10-16 atmospheres. These compressors easily cope not only with painting a car, but also a truck, and also enable several people to work. They are virtually immune to overload, making them ideal for professional painters.

Basic parameters required for painting

For a high-quality painting of a car, it is necessary that the compressor has certain operating parameters. The main technical characteristics are the air consumption, its pressure, the volume of the receiver (the more, the longer the work without interruption) and, accordingly, the engine power and the phase of the motor itself.

In order to bring the car to a practically new state (to paint it superbly), I recommend choosing a compressor with the following technical indicators:

• The volume of the receiver is from 100 to 270 liters (depending on technical features and purpose). Note that small compressors with a 25 liter receiver may be suitable for infrequent painting in a home garage;
• Productivity. from 200 to 500 l / m and more. 200-300 l / min for home, 500 l / min and more for service stations;
• Pressure. this parameter is adjusted on each compressor. If you do not need 10 atmospheres, you freely reduce it to 5.4 or even 2, depending on the work, the parts being processed or the spray guns with which you work.

The main mistakes a buyer makes when buying a compressor

In order to choose the right compressor and not make a mistake, it is necessary to study the technical documentation and determine the final purpose of such a unit. The main miscalculation when choosing a compressor is that in most cases the buyer incorrectly estimates the technical parameters of the device and their compliance with the intended operation. If you are not sure about something, it is better to ask professional consultants or consult with those people who are actively involved in painting. Also, there are often problems with the wrong selection of pneumatic tools. As I explained above, do not try to chase high pressure, because this is not the most important parameter for which you need to buy a compressor, only all parameters together will give effective operation.

Let’s summarize. if you are not going to do large-scale painting, but mainly you will pump up the wheels, paint some little things, or blow out small parts, choose small compressors with small receivers, they just belong in the garage. A service station often needs a large receiver volume, a powerful engine, preferably two-piston, then your work will be successful, and customers will be satisfied with the quality.

And finally, I will repeat myself. the efficiency of the model depends on the number of pistons. But it is worth noting that their volume and material of performance also play an important role. The best compressor is with a cast iron cylinder, so look for just such, and do not try to take the worst quality, but a two-cylinder.

Linear compressor

A linear compressor has a similar structure to an inverter compressor due to the fact that it also has no unnecessary points of friction, since the pistons of such a compressor work due to the electromagnetic field. This eliminates unnecessary noise during the operation of the compressor and, which is important, eliminates additional wear of the compressor parts. However, there are differences between a linear compressor and an inverter compressor. The main such difference is that, unlike an inverter compressor, a linear compressor, after reaching a predetermined temperature in the refrigerator chambers, turns off, and at the necessary moment resumes its work.

Thus, the linear compressor combines all the advantages and disadvantages of both types of compressors. The main ideologist of the introduction of the linear compressor type in modern refrigerators is LG. Nevertheless, thanks to proprietary technologies from various manufacturers, refrigerators with linear compressors are not much inferior to those equipped with inverter compressors, and if we compare them with those that use conventional collector compressors in their design, then a clear advantage can be traced to linear counterparts. Linear compressors are most often used in refrigerators with a dry freezing system (No Frost) and have a separate temperature control system in different chambers of the refrigerator.

Inverter compressor

However, if we are interested in a more modern type of refrigerator, then we should pay attention to the inverter compressor. As a rule, a refrigerator is not bought for the short term, because such a device has been working in our homes for decades. Thus, if you decide to change your old refrigerator for some reason unknown to us, then most likely you may not be aware of the current trends in this direction and may not have heard anything about refrigerators with inverter compressors at all.

The main feature of such compressors is that during its operation, the inverter compressor does not stop, but simply reduces the speed of its compressor. The main advantage of such a system is that during switching on, a conventional compressor reaches its peak, and in one day of operation, a huge number of such switching can occur. When the compressor reaches its peak, it is subject to faster wear and tear, and its life is thus reduced. Unlike conventional compressors, inverter compressors do not stop working even when the temperature in the refrigerator chambers has reached the required level, but only decreases their speed. The wear of compressor parts is thus significantly reduced, and its service life is longer.

Today Samsung is considered the main developer of inverter compressors for its refrigerators. It was their refrigerators that were the first to be massively equipped with inverter compressors. Very often, refrigerator manufacturers using an inverter compressor give a 10-year warranty on the compressor. This can be further proof of the reliability of this type of compressor. The main advantages of inverter compressors can be considered the durability of their operation, the quietness of their operation, which is important in modern living conditions, and the economic efficiency of using this type of compressor.

Which compressor is better for the refrigerator.

The refrigerator is one of the most essential household appliances. Thanks to this device, we can keep our favorite foods fresh for longer.

What should you pay attention to when the question arises of what kind of compressor should be in our refrigerator? Do we really have to learn and memorize many different compressor manufacturers that we have never heard of or knew about before, or is it enough just to choose a compressor, for example, not made in China? These questions are undoubtedly important, but the more important issue in the compressor selection approach is understanding its technologies. Many modern manufacturers use compressors of a newer modern type in their refrigerators. They are considered to be more economical, quieter and, most importantly, more durable. Let’s try to figure out what kind of compressors we can find in modern refrigerators.

Refrigerator Bosch KGN36XL306

Refrigerator LG GA-B379SLUL

Refrigerator Samsung RB33J3000SA / UA

Manifold compressor

Receiving information about new modern refrigerators, we can hear or read information about refrigerators with a so-called conventional compressor on various sources. The question immediately arises if there are ordinary compressors, then there are unusual ones. A conventional compressor is the same collector compressor that is installed in most refrigerators. The collector compressor works according to the principle and technologies familiar to most of us, which were developed and applied in life many decades ago. Simply put, a refrigerator with a collector compressor works until the required temperature is set in the refrigerator chambers, after which the compressor turns off.

There can be one or two such compressors in the refrigerator. In the event that there are two of them, then one of them works for the refrigerator, and the second for the freezer. Nevertheless, in modern refrigerators, two compressors are used less and less at once due to the greater practicality of one unit. Compressors of this type are mainly installed in inexpensive or even budget refrigerators. In refrigerators with collector compressors, both drip (static) and dry freezing systems (No Frost) can be used. The main advantage of the collector compressor over the others is its low cost, because refrigerators equipped with a conventional compressor are much cheaper than others.

So which compressor is better??

Asking the question of which compressor is better, it is rather difficult to answer this question. It all depends on what kind of refrigerator you need, what parameters are paramount for you and which manufacturer of refrigerators is most attractive to you. The thing is that some refrigerator manufacturers are developing their own compressors for their refrigerators, the most popular and well-known manufacturers in this regard are the Samsung and LG companies we have considered today. Let’s try to summarize the advantages and disadvantages of certain compressors that are most common today.

Benefits of collector compressors:

Collector type compressors are also known as conventional compressors. They are installed in most modern refrigerators. Their main advantage is that refrigerators with this type of compressor are significantly cheaper than their counterparts with other types of compressors.

Advantages of inverter compressors:

Inverter compressors are a more modern type of compressor and are used in refrigerators with a No Frost freezing system. Such a freezing system does not require regular defrosting of the refrigerator, and the compressor itself successfully adjusts to the temperature regime of the environment and the one that is installed inside its chambers. Due to the fact that inverter compressors can regulate the power of their work, they are quieter than conventional compressors, but have a longer service life.

Benefits of linear compressors:

At first glance, it may seem that linear compressors have absorbed all the best that both types of compressors have in themselves. inverter and collector. They work just as quietly and accurately maintain the temperature regime inside the refrigerator chambers, and their cost practically does not differ from analogues with a collector compressor. However, a linear compressor, just like a conventional compressor, has a periodicity of its operation and those moments when it turns on and off.

Thus, having considered all the best aspects of various refrigerator compressors, it will not be so difficult for you to choose the most optimal one for yourself.

What compressor is needed for a wrench?

The main purpose of the nutrunner is screwing and unscrewing any fasteners. A similar tool can be found in a modern auto repair shop offering tire fitting services, or in the suitcase of a specialist in various types of installation. Complete with a compressor, a wrench will significantly save operating time and reduce power costs.

Make sure the kit is effective:

• instant loosening / tightening of bolts and nuts,
• increased operator efficiency due to high compressor power,
• wide range of applications: used where conventional wrenches and electric wrenches are powerless; quickly unscrew the rusted and tightly “stuck” nut.

Design and working principle

The compressor for the impact wrench consists of a practical housing and a double-acting pneumatic cylinder. The body is equipped with a power lever with a square sonnet, which is necessary for installing interchangeable heads.
The compressor compresses the gases and supplies air under pressure to the wrench, making it work.

Types and purpose of the compressor for the wrench

A compressor for a wrench or other pneumatic tool must be suitable for the purposes of future use. Depending on the purpose, there are the following types:

• Reciprocating compressors for a wrench are the best option for a garage. Compact model suitable for servicing your car.
• Oil-free reciprocating compressors. installing a fence, fence or building facade are just a few of the tasks they can handle perfectly.
• Belt Compressors — Designed for long, hard work. Compressor endowed with a long service life thanks to the engine cooling system.
• Screw units. accurate and meticulous work. their strong point. Compressors like these deliver clean air and high performance.

When choosing a compressor for a wrench, it is important to consider:

• Torque indicator.
• Idling speed (selected depending on the required intensity of work).
• Fit Size (for Fitting Impact Sockets).
• Length of the working shaft of the tool.
• Air consumption (depending on the compressor available).
• Machine weight.
• Type of shell.

Another indicator that you should pay attention to when buying a compressor is performance, that is, the amount of air that the device can compress in 1 minute. It depends on how efficiently the pneumatic tool will work.

We recommend choosing models whose performance is 2 times higher than the wrench can spend. If the tool needs 100 liters of compressed air to work, the compressor should supply about 200 liters.

It is also important if the compressor has a cooling element. The case heats up during compression and the device may need to take a break. The presence of a cooling system will allow the compressor to work for a long time without rest.

Compressor selection for pneumatic impact wrench

Many motorists, buying a pneumatic wrench, are wondering what kind of compressor is needed for this unit. First of all, you should pay attention to its performance according to the passport. There is one caveat here: some companies that produce compressors, in order to increase sales, indicate the performance not at the outlet, but at the inlet. For example, the documentation for the unit indicates its productivity of 210 liters per minute. This means that this indicator should be interpreted as the speed of air injection by the compressor into itself, that is, into the receiver. At the exit, the productivity can drop by about 30-40%. And it turns out that the unit actually produces only 146-127 l / min.

Based on the foregoing, it can be understood that if the compressor indicates a capacity of 210 l / min, then you need to choose a wrench with significantly lower air flow rates. For example, if the operating speed of the air flow at the tool is 200 l / min, and the compressor, according to the documentation, is 210 l / min (in reality. 146-127 l / min), then you will not be able to unscrew or tighten anything with such a tool.

In addition, the volume of the receiver also plays an important role. In household appliances, a cylinder can have a volume of only 24-50 liters. Under these conditions, the impact wrench will not work properly. Even with a receiver volume of 50 liters, after a few seconds of operation of the tool, the pressure in it decreases significantly, and to continue working you have to wait until it recovers. Therefore, the compressor receiver must have a volume of more than 50 liters, and the unit itself must create a pressure in it of at least 6.2 kg / cm². Otherwise, the device will not be able to develop the required power.

But too high pressure in the system should not be allowed. Exceeding the recommended pressure indicator has a detrimental effect on the main units of the tool, leads to their rapid wear and, as a result, to the failure of the nutrunner.

The result of the above is this: if the tool is designed for an operating air speed of 119 l / min, and the compressor for the wrench produces 135 l / min in reality, then it can be used to unscrew and tighten the fasteners on the wheels without any problems. But do not forget that the tool must have a torque of at least 550 Nm.

The choice of oil for the wrench

The lubrication of this pneumatic tool should be taken very seriously. If the unit can work without purified air for some time, then without lubrication it will fail very quickly. Oil entering the moving parts of the machine reduces friction between them, and also removes wear products in the form of fine dust. This dust is able to fill the gaps between the blades and the rotor, which slows down their movement. As a result, the power of the tool is significantly reduced. The problem is solved by installing a lubricator in the system. The photo below shows its linear type.

But the installation of an “oiler” will help to extend the life of the nutrunner only if it is filled with a special grease intended only for pneumatic tools with the required viscosity.

Try to get the wrench oil recommended by the tool manufacturer. As a last resort, only synthetic oil should be used, which has good anti-wear and anti-corrosion properties and does not contain silicone.

It is impossible to pour gear or engine oil into the lubricator, since it has a higher viscosity than required, and successfully “glues” the blades of the pneumatic drive, due to which the unit loses power.

Special grease is also available from pneumatic tool companies.

Features of the operation of a pneumatic wrench

Any craftsman knows that the most laborious process when assembling structures or repairing mechanisms is loosening and tightening threaded connections. But if pneumatic wrenches are used for these purposes, then such work turns into an ordinary formality. This convenient tool has many advantages, but you should learn more about the nuances of its operation.

Rules for applying grease

If for some reason you are not able to install the lubricator on your unit, then you can get out of the situation in the following way.

• Immediately before starting the nutrunner, unscrew the hose from it and drip 3 to 5 drops of grease into the tool fitting.
• Next, you should return the hose to its original place and turn on the unit for a short time (thirty seconds will be enough). Thanks to this operation, the oil will be evenly distributed over all moving parts of the device.

Lubrication in this way must also be carried out before long-term storage of the tool. When using the unit in intensive mode, oil should be instilled into the fitting every 3-4 hours.

Although this method helps to extend the life of the wrench, it is very inconvenient. We have to interrupt work and spend time cleaning the tool from contamination in the area of ​​the fitting, preparing the lubricant. Also, during the procedure, you should carefully monitor that dust does not get into the unit. It is for these reasons that it is recommended to install a lubricator in the system, which will always supply lubricant to the tool in a timely manner.

Why does a compressor need a filter

The air leaving the compressor must be clean, that is, free of various impurities that can damage the wrench. Not everyone knows that condensation forms in the interior of the receiver during air compression. Also, oil can enter the receiver along with the forced air if the mechanical part of the unit is severely worn out. Oil, mixing with condensate (moisture), takes the form of an emulsion and enters the instrument through a hose connected to it. This emulsion can corrode all mechanical parts of the unit. For this reason, nutrunners filled with water and rust, with failed components, often end up in service workshops.

In order not to bring the tool to such a deplorable state, it is customary to install a filter-drier on the compressor. Inside it is a filter mesh made of bronze using a special technology.

The air passing through the filter gives off moisture and loses all impurities that enter the sump. Typically, the body of the moisture trap is made of a transparent material to track the amount of contamination accumulated during operation.

The sump also has a valve (located at the bottom) through which all impurities are easily removed.

Hose selection

You should be aware that the hose that comes with the compressor, especially the Chinese one, is not suitable for the effective operation of the wrench. Most often, these hoses have an internal cross-section of about 6 mm. This hose capacity will not be enough to supply the required amount of air to the pneumatic tool. They, perhaps, can blow off dust, apply for a spray gun, but no more. Even inflating tires with it takes a lot of time.

The device and principle of operation of the pneumatic wrench

In the figure below, you can see in detail the device of the pneumatic wrench. The unit consists of the following elements housed in a robust metal case.

• High performance air motor.
• Impact mechanism.
• Alloy steel chuck (stop).
• Torque regulator, and reverse.
• Start button.
• Fitting, for connecting a hose from the compressor.
• Air valve.

Due to the absence of a motor, this unit is much lighter than its electric counterpart. And the torque of the wrench has high performance. from 300 to 2200 Nm (Newtons per meter).

Inside the unit, 2 main power units can be distinguished, each of which is designed to operate in different modes. The first unit is an air motor that transmits rotary motion to the tool head. The second block is the node that creates shock loads. The pneumatic actuator rotates due to the passage of compressed air through it, supplied by means of a high-pressure hose from the compressor.

There are 2 channels in the body of the device. For each of them, air is directed in different directions relative to the turbine. In the first case, the air pushes the turbine in the clockwise direction, that is, for twisting, and in the second, against the clockwise arrow, for unscrewing the fasteners. Air flows are distributed by a special switch.

The principle of operation of a pneumatic wrench is as follows.

• After pressing the start button, the valve opens, and the air flow from the hose connected to the body of the device begins to move through the turbine, rotating it.
• From the turbine, the rotary motion is transmitted to the impact mechanism, which in its principle of action resembles a clutch. The mechanism includes 2 cams of complex configuration. The impact force is generated by the cams when there is not enough torque when the fastener is released.
• Further, the rotational movement is transmitted to the stop (chuck), on which the nozzle is put on for a certain size of the nut. As a result, the fasteners are twisted or unscrewed. Some air wrenches do not use the impact mechanism when tightening, the process takes place in a shockless mode.
• If the nut is stuck, then to unscrew it, more effort will be required, and at this moment the rotation of the stop stops.
• Hammers begin to tilt back while turning.
• At the next stage, the cams pass the engagement with the stop and, continuing to move, gain momentum.
• Continuing to turn, the cams again engage with the stop and strike it (in the direction of travel).
• Shock impulses continue until the fastener “breaks” from its place.

Thus, with the help of a pneumatic impact tool, the process of loosening tight bolts and nuts is easy and quick.

What parameters should be used to choose a compressor for sandblasting?

When organizing a car body repair service, the question arises of cleaning metal from dirt, rust and old paintwork. To quickly remove all unnecessary components from the metal surface, use sandblasting. A jet of sand mixed with air will quickly remove all non-metallic materials. Before the creators of a small car repair business, the question arises: “What kind of compressor is needed for a sandblaster?”

Similar devices are used not only in the garage. When repairing bridges or building structures where old plaster needs to be removed, use high pressure abrasive blast attachments. Glazing of interior items has been a fashionable trend in the manufacture of furniture for many years. An additional option is the application of a pattern on glasses and mirrors using sandblasting. The scope of application of the device for abrasive processing is quite extensive. The heart of any of them is the compressor.

• Basic parameters for selection
• Why is excess pressure needed??
• Criterias of choice
• Compressors for work
• Compressor unit design
• How to operate compressors in winter?

Basic parameters for selection

Based on the experiments, it was found that for the treatment of a metal surface with an area of ​​several square meters, it is required to provide a continuous supply of an abrasive jet mixed with air weighing 0.05. 0.07 kg / s. The volumetric ratio between sand and air is (0.01. 0.012): 1. It turns out that to supply sand, you need 100 times more air in volume.

To provide this amount of compressed air, the compressor capacity must be 12. 15 l / s (720. 900 l / min). An important parameter will be the pressure generated by the pneumatic machine.

In the theory of gas outflow through a nozzle, the formula is used:

• k is the adiabatic exponent. For diatomic gases (a gas mixture of nitrogen and oxygen is a mechanical compound of diatomic gases) k = 1.4;
• pкр. critical gas pressure in front of the nozzle, bar;
• p₁ is the gas pressure of the environment where the outflow occurs, bar;
• v₁. specific volume of air, kg / m³.

To clarify the critical pressure, use the formula:

For diatomic gases, the critical value is βcr = 0.528. In a conventional expanding nozzle, it is impossible to achieve a speed higher than the speed of sound for a given gas at the appropriate temperature. Therefore, talk about the need to have high pressure at the nozzle inlet is unfounded.

Criterias of choice

When choosing a compressor unit, they are guided by a number of indicators:

• Air hose diameter. They use reinforced hoses, they are also called oxygen hoses. Their flow area is 15 or 19 mm.
• Abrasive material hose diameter. In practice, a reinforced hose with a diameter of 15 mm is used.
• Nozzle diameter. The size of the nozzle at its narrowest part is responsible for the air flow rate per second. The use of a large diameter nozzle is not justified, it will be quite difficult to hold the sandblast in your hands. Therefore, in practice, it has been established that the optimal use of a nozzle with a diameter of 4.0. 5.0 mm. Then the required jet of abrasive feed mixed with air will be obtained.

Based on the above, the requirements for the compressor are determined:

• Minimum minute feed. 1200. 1500 l / min.
• Developed pressure. up to 7. 8 bar.
• The power consumption of such devices is 2.0. 3.0 kW.

As a result of the analysis of the operation of several units, data on the performance of sandblasting plants were obtained. The range of acceptable parameters for a small car repair shop is highlighted in yellow. During the research, river sand was used with a density of 1600. 1650 kg / m³.

Main factors	Nozzle diameter, mm
	3.5	4.0	4.5	5.0	5.5	6.0	6.5	7.0	7.5	8.0	8.5
Abrasive consumption, kg / h	120	165	210	255	300	345	390	435	480	525	570
Air consumption, m³ / h	1.1	1,3	1.5	1.7	1.9	2.1	2,3	2.5	2.7	2.9	3.1
Productivity for surface treatment, m2 / h	3.5	4.2	4.9	5.6	6.3	7.0	7,7	8.4	9.1	9.8	10.5
Power consumption of the drive, kW	1.6	1.9	2.5	2.9	3.4	3.8	4,3	4.7	5.2	5.6	6.1

Compressor unit design

When choosing a compressor, it is recommended to decide which motor will be used for the drive. Usually use:

• Electric motors, they run on a 220 or 380 V network.
• Gasoline engines consume A-92 gasoline as fuel (usually four-stroke devices are installed, but some manufacturers also install two-stroke engines).
• Diesel power plants. Diesel oil is used as fuel.

Types of drives for domestic and industrial compressors:

Compressor equipped with a diesel engine. Power is 12 kW, equipped with a 350 l receiver:

Heat engines allow compressors to operate in an autonomous mode. Such installations are operated when performing work at a distance from power sources. They are used to work on remote construction sites:

• During the repair and construction of bridges and overpasses. There it is necessary to clean the reinforcement from various impurities before the subsequent pouring with concrete.
• With the destruction of decommissioned objects. The country is undergoing extensive renovation of the housing stock. We have to carry out the destruction of buildings unsuitable for habitation. They contain significant volumes of metal frames. For the removal of construction waste, the reinforcement must be removed. Cleaning is assisted by sandblasting machines.
• If it is necessary to use high-performance equipment, compressors based on diesel or gasoline engines can produce tens of cubic meters per minute.

The household compressor uses a single cylinder device. It is driven by a V-belt. It is these installations that have become widespread in small car repair shops:

• Electrical equipment with a power supply of up to 3.0. 3.5 kW is usually operated from a 220 V. They are connected with ordinary plugs. At the same time, the consumed current does not exceed 15 A. Such installations are used in small industries or by individual entrepreneurs engaged in car repair.
• If it is necessary to use more efficient installations, a 380 V network is used for power supply. It is capable of connecting compressors that consume up to 90. 100 kW of electricity. Such installations can produce up to 5. 10 m³ / min. Such devices are installed in industrial plants.
• In factories or workshops, they try to place power equipment in a separate room. Then the sound from working devices will be less tiring for the hearing of workers. The supply of compressed air from the compressors is carried out through pipes.
• Polypropylene pipes are widely used in modern enterprises. They are easy to weld together, it is not difficult to organize branching and distribution to different consumers.
• In order to evenly load the network with compressed air, receivers are installed near the consumers. They smooth out pressure pulsations. The available reserve allows you to operate the technological equipment in optimal modes.
• For sandblasting work, they try to place a 500. 800 liter receiver near the object. Then, during operation, a performance margin will be provided. The work will be performed in a stable mode.

compressor for sandblasting.

Why is excess pressure needed??

Compressors in operation develop a pressure of 4… 8 bar. It cannot be used, but it must be created. The reason is simple: you need to have a supply of compressed gas in the receiver. After the pressure is built up, regulated by the regulator, the machine is automatically turned off. It will turn on when the value in the receiver drops below the set minimum.

Therefore, when selecting compressors, they are guided by the possibility of creating an overpressure of up to 6. 8 bar. The bigger, the better.

Compressors for work

Modern compressors for process equipment are manufactured in piston or screw design. During the operation of screw compressors, the process of gas compression occurs due to the rotation of two screws.

Screw compressor design:

Screw compressor device: 1. housing; 2. rotor screw; 3. roller bearing; 4. ball bearing; 5. bearing support; 6. sealing gland; 7. end cover; 8. a pair of gears of the reducer.

Piston compressor working process: 1. suction valve; 2. discharge valve

The compressor operation process is easiest to understand by considering the diagram of the piston device. There are:

• cylinder;
• piston;
• crankshaft;
• intake and discharge valves located in the cylinder head.

• When the crankshaft rotates, the piston reciprocates. In this diagram, they move up and down.
• When the piston moves downward, a vacuum is created inside the cylinder. This opens the suction valve. Air from the environment enters the cylinder.
• When the bottom dead center is reached, the volume expansion process stops. The piston starts moving up.
• The pressure inside rises. As a result, the intake valve closes.
• When the pressure rises above a certain value, the discharge valve opens. Pressurized air is pushed into the exhaust pipe.
• At the end of the push cycle, the valves close. In the future, all the work is repeated.

Structurally, industrial plants have not one, but several cylinders. Therefore, during their operation, the work takes place in a smoothed mode. Flywheel balances vibration.

Multi-cylinder reciprocating compressor design:

During operation of the screw compressor, air is sucked in from the environment. The profiles of the screw pair are made in such a way that when the gas is pushed in the spaces between the screws, the volume constantly decreases. There is a gradual compression of the working fluid.

The cycle takes place without abrupt reciprocating movements. The wear in this design is minimal. Therefore, most users consider using screw compressor machines. Their higher reliability has been proven over time. Therefore, if it is possible to choose one or another type, then it is better to opt for screw systems.

For normal operation of the compressor units, cooling must be carried out. Industrial units have a water jacket for cooling. Small units are cooled by a fan that blows around the ribbed surface of the cylinder and cylinder head.

How to operate compressors in winter?

When operating the unit in winter, it must be remembered that condensation forms in the pipelines. If it is not removed regularly, it may freeze. Therefore, industrial enterprises establish regulations for the maintenance of compressor stations. Every day before starting work, drain the oil-water condensate. For powerful devices, for 8. 16 hours of operation, up to 20. 35 liters of a similar mixture is recruited.

For sandblasting installations, the presence of moisture in the system is unacceptable. The abrasive material gets wet. Traces of oxidation remain on steel surfaces. Equipment is damaged.

What Size Air Compressor Do You Really Need?

Attention! An emergency pressure relief valve must be installed when using abrasive cleaning plants. Shut off the compressed air supply and open the safety valve. Air leaves the receiver quickly.