How to choose a dehumidifier or make it yourself


The air compressed by the compressor often contains particles of moisture or oil, which are not desirable to enter the system. To remove impurities from the compressed air, a compressor dehumidifier is installed. In some cases, without this element, work using pneumatic tools becomes impossible.

The purpose of the dehumidifier in compressors

For the organization of the correct operation of the pneumatic tool, a very important indicator is the purity of the compressed air that is supplied to it. First of all, it must be cleaned of dust. Used to remove mechanical contaminants air filter, installed at the inlet to the unit. Also, moisture must be removed from the air masses, which, when compressed, condenses in the receiver and in the system itself. An air dryer is installed to remove moisture from the compressor outlet.. In addition to moisture, compressed air can have oil particleswhich inevitably fall into it.

On a note! The mixing of oil with air during its compression is typical for an air piston and rotary (screw) compressor, since the operation of these units requires the presence of lubrication.

If the air is not cleaned of moisture, then the following happens:

  • when moisture is mixed with oil, an emulsion is formed, which is capable of clog pneumatic channels;
  • at low temperatures, moisture in the pneumatic channels freezes, which can cause blockage or damage;
  • rust accumulates in the air ducts, which over time can completely block the air supply;
  • when moisture gets into the pneumatic tool, it parts start to rust and quickly fail;
  • the resulting air-oil mixture in its composition cannot meet the requirements for its use in the food, electronic, pharmaceutical and chemical industries;
  • in the presence of moisture high-quality painting becomes impossiblesuch as automobiles, as the paint will not adhere tightly, causing bubbles to form and cause it to peel off.

The device and principle of operation of the part

Standard water separator device vortex type for pneumatic systems shown in the figure below.

Swirl Type Standard Dehumidifier Device

This node consists of the following elements.

  1. Frame. It is attached to the pneumatic line and is the basis for the entire moisture separator.
  2. Cup. Forms an internal cavity in which the deflector (3), filter (4), damper (5), plug (7) and impeller (8) are placed.

Working principle of the dehumidifier simple enough. After entering the housing (1) of compressed air, it moves towards the impeller (8). Once on the impeller, which has guide vanes, the air swirls. Under the action of centrifugal force, all particles in the air move to the walls of the glass (2), where they condense and roll down. A damper (5) is provided to separate the quiet zone in which the dirt (6) is located. Further, the air flow enters the deflector (3) with a filter (4) installed, which traps fine solid particles of contaminants. Accumulated impurities are removed through the stopper (7) installed at the bottom of the glass.

Varieties of air purification systems

To clean compressed air, both for industrial and domestic purposes, several types of dehumidifiers are used: vortex dehumidifiers, adsorption dehumidifiers and modular cleaning systems.

Vortex filters

The vortex-type moisture-oil separator has a cylindrical shape (the device was discussed above) and cleans the air due to its swirling in the chamber (glass). The vortex oil separator is the most common device for cleaning compressed air from moisture and grease particles.

Moisture-oil separators adsorption

To remove oil and moisture from compressed air, substances with active absorbent properties are used, for example, silica gel, aluminum gel, calcium chloride etc. The following figure shows an adsorption type oil and moisture separator.

air currents

Modular cleaning systems

The best results in removing condensate, oil particles and dust from the air are provided by a modular cleaning system.. It consists of several elements: a cyclone (vortex) separator, a fine filter and a carbon filter. The following figure shows a modular type oil/water separator.

Modular apparatus

Important! Modular systems provide at the last level of purification almost one hundred percent purity of technical air that enters blow guns, pneumatic tools, spray guns and respirators (without a carbon filter).

Key Equipment Features

The scope of moisture-oil separators is quite wide, therefore, when choosing a model, it is worth immediately identifying its specific goals and objectives: maintenance of MAZ / KAMAZ class vehicles, pneumatic tools or other devices where high-quality filtration is required.

If we take into account the technique for work with paints and varnishes on pneumatics, then the need for an extended throughput is eliminated. Here it is much more practical to look towards equipment with fine filters.
While for production needs it is precisely good patency that is required, and the micron indicator for cleaning fades into the background. The latter depends on the fraction size. Industrial options are more logical to use for high-quality water treatment. In this case, small particles with a size of about 5 μm are cut off. Classical solutions are mostly equipped with filter systems, the fraction of which fluctuates around 15 microns.

industrial dehumidifier

Industrial dehumidifier

Special attention should be paid pressure rating. Separators for compressor equipment of the medium budget segment offer a level of 7 bar. This parameter affects the final result to a lesser extent, but the filter must correspond to the output of the unit, otherwise the efficiency will decrease markedly, as well as labor costs will increase.

When choosing a separator, it is imperative to compare the load and power indicators at the moment of compressed air movement inside the equipment. It is also necessary to take into account the features of a particular instrument, namely, connection diameter. It can be 1/8, 3/4 or more rare — 3/8. There are also exotic options for some specific needs.

Top Models

The market offers a wide range of solutions of different formats and brands, which is very easy to get confused. The list below includes the most popular representatives of the segment, which received a large number of flattering responses from consumers.

Wester 816-002

This is an air filter with a working pressure of 10 atmospheres and a full-fledged air preparation unit. The diameter of the input connections at both ends is 1/4F. For visualization of readings manometer provided. The system also includes a lubricator and a gearbox.Wester 816-002

The device holds the pressure well, and the pressure gauge does not lie, as with more affordable solutions. The build quality is also at a high level: there were no gaps, backlashes or other structural flaws. The cost of the separator is in the region of 2500 rubles.

Zitrek SAW 3000-02 D FR 1/4 M

The model can be used as a moisture-oil separator or filter. This solution worked out great. in tandem with a pneumatic tool. The air filter copes well with fine cleaning, and if necessary, is easily replaced with a new one.Zitrek SAW 3000-02 D FR 1/4 M

Universal connection diameter — 1/4M. There is a fairly accurate pressure gauge, as well as automatic condensate drain. The device holds pressure well, but in the absence of it, it starts to rattle a little. The cost of the device is about 1000 rubles.

Pegas EC5000-06

This is a serious model with good returns and a corresponding cost. The device effectively cleans the incoming air from solid particles and condensed moisture. Device in automatic order maintains pressure at a user-specified levelwhile simultaneously removing accumulated condensate.

Pegas EC5000-06

The system includes an oil sprayer, a moisture separator and a pressure gauge. The latter boasts high accuracy. Connection diameter — 3/4. The device withstands pressure of 15 bar and temperatures up to +60⁰С. The quality of cleaning is within 25 microns. The cost of the model is a little more than 6000 rubles.

Licota PAP-C207B

it three-level separator with fine cleaning. The device filters compressed air, effectively removing oil and moisture.

The degree of purification for each level is different — 5, 0.3 and 0.01 microns. This approach does not leave a chance for pollution, allowing you to achieve air purity of almost 100%.

Licota PAP-C207B

The system includes a pressure regulator with an accurate sensor and an automatic condensate cleaning valve. The need to replace the filter elements will be indicated pink colored granules. The cost of the device is appropriate — more than 9000 rubles.

AIST 91030354

The block includes a separator, a lubricator and a pressure regulator. The model has proven itself well in tandem with a pneumatic tool, filtering the air coming from the compressor. The operating pressure is within 10 bar with a flow rate of 4500 l/min.

AIST 91030354

Additionally there is oil flow rate adjustment, as well as the removal of accumulated condensate in an automatic manner. There are no complaints about the quality of the assembly: all elements are tightly fitted to each other and do not play. The model fully justifies its cost, which is almost 7000 rubles.

How to make a dehumidifier with your own hands

Since the design of the dehumidifier does not include high-tech elements, it is quite possible to make an air dryer for compressors with your own hands from improvised materials.

Cyclone (vortex) dehumidifier

A cyclone type dehumidifier can be made from a liquefied gas cylinder, an unnecessary fire extinguisher, or trimming metal pipe of suitable diameter. The length of the pipe can be arbitrary.

The fixture is made in the following order.

  1. Drill a hole in the bottom of the body and weld on a conventional faucet. It will serve to drain the condensate accumulated in the tank. Below is a drawing of a homemade vortex dehumidifier, according to which this device can be made from a metal pipe.
    Unit drawing
  2. An outlet fitting should be welded in the upper part of the body.
  3. A hole is made in the lower part of the pipe (cylinder) (not lower than 150 mm from the bottom) and an inlet fitting is welded so that air enters the container tangentially. Due to this, a swirl will occur in the tank, which helps to clean the stream from contaminants.
  4. Further, it is necessary to weld 3 legs equipped with nickels (for stability) to the body.
  5. If desired, the resulting fixture can be painted.

Homemade unit

Advice! For proper operation of the device, it must be installed vertically.

Homemade adsorption dehumidifier

A homemade dehumidifier is easy to make from a water filter and silica gel cat litter.

Cat litter

You will also need a small metal or plastic tube and a glue gun.

The filter for cleaning the air from condensate is made as follows.

  1. Cut the tube long enough to fit into the lid and reach the bottom of the filter.
  2. It is necessary to drill several holes in the tube through which compressed air from the compressor will pass.
    Holes in the pipe
  3. A plug should be inserted at one end of the tube so that it does not clog when lowered into silica gel.
  4. The upper end of the tube must be inserted into the filter cover and sealed with a glue gun.
    Sealing the joint with a glue gun
  5. At the top of the tube or in the cap, set gridwhich will prevent the filler from entering the duct.
  6. Next, you should pour the silica gel filler into the flask, insert a tube with a lid into it and tighten it well.

Now you can connect a hose from the compressor to the inlet fitting of the dehumidifier, and a hose leading to some pneumatic tool, for example, to an airbrush, to the outlet.

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