Rotary compressor units have become widespread in enterprises and small workshops. Compressed air equipment of this type is characterized by a robust design that ensures high performance. To this should be added the practicality in the maintenance of the unit. At the same time, rotary compressors have a number of disadvantages that limit their use.
Compressor device
Rotary models represent a whole group of compressors that differ in design and performance. The main share of stations of this type are air rotary installations. In this case, the device of rotary compressors is based on the motor shaft, which provides the operating function. A rotor is mounted on the shaft, but during operation, the movement is carried out not from the center of the circle, but eccentrically. This is due to the fact that the shaft of traditional models has an offset.
The functional filling, in turn, is enclosed in a metal case - usually cylindrical. Without fail, a technological gap is maintained from the shaft with the rotor to the surface of the housing. Rotary during operationthe air compressor will shorten it according to the amount equal to the above shaft displacement. Also, special plates and dampers are used for additional protection and prevention of overflow of technical fluid.
Working principle
With each revolution of the rotor, a free zone will be formed between the cylinder wall and the working group. At this point, it is filled with dry superheated or saturated steam - these can also be varieties of refrigerants and oily liquids. On the other hand, the discharge valves begin the process of compressing this zone, which contribute to the suction of the same vapors from the evaporator. When performing a multiple cycle of revolutions, the optimum operating pressure is reached, allowing it to perform the main function of forcing compressed air, for which a rotary compressor is used. The principle of operation of rotary models also provides for automated oil supply. This is especially true for industrial units operating at high loads. Filling with liquid is carried out from a special tank - it enters the oil separator up to a certain level. If necessary, the oil can be cooled with water.
Design types
Usually allocate rotary type compressors with oscillating and fixed compression elements. The first model of the working group assumes the compression of the refrigerant by means of a rotary eccentric on the engine. It is in some way an independent element, providing a relatively high degree of compression. However, due to increased friction, suchaggregates are considered inefficient. At least costly in terms of maintenance. On the other hand, rotary vane compressors can eliminate the undesirable effect of intense friction. The compression of the refrigerant is realized by plates fixedly mounted on the shaft. They are stationary relative to the shaft itself, but they perform their compression function together with it.
Features of spiral models
Scroll models are more commonly used in small to medium power applications such as refrigerators. The working group is formed by two metal spirals - one is integrated into the other. In this case, the base spiral is stationary, and the outer one rotates around the axis. More importantly, in compressors, these elements have a special involute profile that allows them to roll but not slip. Assumes a scroll compressor and moving the point of contact of the working elements. It is in it that the cycles of compression and expulsion through the central hole occur. By the nature of the compression, spiral aggregates can be called softer and more gentle. Therefore, the output power allows them to be used in equipment of medium and low productivity. It is worth emphasizing the complexity of the technical implementation of such compressors, due to the need to maintain a snug fit of the scroll elements and the tightness of the ends.
Implement safety systems
The high quality of the element base and the carefully calibrated layout of functional parts are not enough forto ensure that the equipment regularly performs its tasks in the production environment. Therefore, modern models cannot do without additional protective systems. First of all, this is an automatic shutdown of the unit when network overloads are detected. Thus, the motor control unit is protected. Since rotary compressors are also prone to overheating of the mechanical part, the cooling system is also being introduced into the design. It minimizes thermal loads that affect both technical fluids and structural details. For models with electronic control, self-diagnosis systems are provided. Thanks to the sensors, the compressor can detect malfunctions of the components without the participation of the operator and, depending on the nature of the breakdown, either correct them on its own, or give the appropriate alarm signal through the indicators.
Key Features
Compressor performance determines which equipment a particular model can work optimally with. This characteristic is expressed as the ratio of the released volume of air to a unit of time - usually a minute. Household units most often have a capacity of about 100 l / min. This is quite enough for working with pneumatic tools like sprayers, grinders and hammers. But if, for example, the simultaneous use of several pneumatic devices is planned at the construction site, then the productivity should increase to 150-200 l / min and above. In addition, it is desirable to use a compressor with a rotating rotor with a margin of power potential. That is, to the total planned load you needwill add 15-20%. This increase is justified by a decrease in the load on the element base. An essential characteristic is the operating pressure, which varies on average from 6 to 15 bar. In this case, the selection is also made based on the requirements for a particular tool. For optimal performance, add 2 points to the pressure rating of the tool.
Consumables
Oil plays a special role in the working process of rotary compressors. The main function of compressor fluids is to maintain the wear resistance of parts, prevent depressurization and the formation of deposits. But modified compositions with certain improved properties are also on the market - for example, it can be frost resistance, anti-corrosion protection, etc. As for the type of base, a scroll compressor operating at temperature loads up to 100 degrees can be charged with synthetic means. If this threshold increases, then you should turn to more expensive, but high-quality mineral oils. Technical accessories are also a necessary addition. In this group of consumables, hoses, adapters, fittings, valves, filters and fasteners are distinguished. Thanks to the component equipment, the infrastructure for the interaction of the compressor with the working tool or equipment is organized.
Producers and prices
Although the compressor segment as such is very extensive and offers products from almost all major manufacturers of the construction and industrialequipment, the category of rotary models is the least popular, and therefore the offers are significantly limited. The most popular are the installations of manufacturers of refrigeration equipment Matsushita, Galanz, Toshiba, etc. They cost from about 20 to 50 thousand rubles. For building and industrial use, the firms Abac, FUBAG and COMARO are recommended. These companies offer mainly high-performance units designed for operation in large enterprises. In terms of price, rotary compressors of this type also differ markedly - on average they cost 200-300 thousand. By the way, one of the most expensive stations is offered by Abac in its GENESIS line. This is a model with a capacity of 3320 l/min and an operating pressure of 8 bar, available for 650k
What to consider when choosing?
Rotary compressors are typically chosen by users who need a low cost, low noise yet high performance source of compressed air. Therefore, the industry with all its operating features will be the main area where this type of compressor is used. A rotary engine most often focuses on a mains voltage of 380 V. If there is no three-phase line at the site of use, then you will have to make allowances for performance, focusing on 220 V. In addition to the main operating values, the design is also taken into account. Usually it is stationary, but even large-sized modifications in some versions provide for the possibility of movement. This point must be kept in mind ifthe facility is planned to serve several technological points located in different locations.
Maintenance
Under regular operating conditions, preventive inspection sessions should be performed according to the schedule. An oil change and an inspection of the connecting parts are performed before each procedure for using the equipment. If critical deformation of elements or wear of consumables is detected, air compressors are repaired, which can be expressed by replacing faulty components. Technical restoration of the same deformed elements is undesirable, since their service life will be lower in any case.
Special attention is paid to the channels for the supply of oil and coolants. Filters, membranes, seals and hoses interact with them - this infrastructure should be regularly cleaned, flushed and also replaced if necessary. By the way, the repair of air compressors in the form of restoration of fan blades and a radiator grille is carried out just in those cases when the maintenance personnel paid insufficient attention to the fight against blockages and contamination of the structure.
Application areas
It has already been said that compressor units are often used to service construction tools on a pneumatic basis. But this is only part of the tasks that units of this type are capable of performing. Their specialized niche is still refrigeration equipment. Moreover, it can be directly industrialrefrigerators with refrigerators, and home air conditioners. In the second case, compact and low-power rotary compressors are used. Application in industry is also focused on the possibility of operating the unit with refrigerants - the equipment is used at the technological stages of processing slaves, meat, semi-finished products and other food products.
Conclusion
With all the differences with reciprocating compressors, rotary units work on the same principle of displacement of the serviced medium. The differences are already determined by the structural implementation of mechanics, which ensures the entire process. Among the advantages that rotary compressors have against the background of reciprocating analogues, one can note the possibility of connecting to the engine, the balance of the stroke with the reduction of vibrations, the uniform supply of gaseous media and the absence of a group of valves. But there are also disadvantages. So, for example, the close interaction of mechanical parts contributes to their rapid physical wear. There are also weaknesses in rotary models in terms of manufacturing technology - they require high-precision assembly, otherwise the unit will not be able to meet the declared performance.
