An oil scroll air compressor is defined as equipment that applies a scroll air compressor mechanism to compress air. This type of air compressor is made out of two helically configured helices, which gives it the common name scroll air compressor. Here is an overview of what an oil scroll air compressor is and how the scroll mechanism works to compress air:
Oil Scroll Air Compressor
A scroll air compressor consists of two scroll members; one is stationary while the other rotates in the shape of a spiral. The scrolling bar moves around the stationary scrolling bar. In its operation, the distance between the scrolls narrows little by little, squeezing the gas (in this case air) between the scrolls. The compressed air is then discharged through the center of the wheel as it is illustrated in the figure below.
Some of the varieties of compressors include the piston type and scroll type of compressors, and the scroll type of compressors comprises fewer parts compared to the piston type, as well as operates more quietly and in some instances, do not vibrate. They are also easier to build and operate since they are simpler, more reliable and require less maintenance. There are so many air compressor manufacturers but Dehaha is one of the most reliable air compressor manufacturers who focus on energy saving.
Lubricant Role
On the other hand, oil is introduced into an oil scroll air compressor to act as the lubricant and a sealant. The oil helps to keep the scrolls in contact and prevents them from wearing out with time due to constant friction. It also acts as a seal between the scrolls as well as other internal parts to ensure efficiency of the appliance. This in turn enables the compressor to reach higher pressure levels without concomitant loss through leaks.
Lubricating oil does not come into contact with the compressed air, it is removed from the discharge air through an oil separator. This results in an oil-free airstream being delivered in the working environment. While a small amount of oil does remain within the air that exits the compressor, an aftercooler further condenses what little oil vapor remains after the compression stage.
Internal Compression Process
The internal compression process in an oil scroll air compressor works as follows:
- The air is forced into the compressor through an inlet valve and fills the gap formed between the stationary and the orbiting scrolls.
- The orbiting scroll starts to orbit while the interval between the scrolls reduces the space between them, squeezing the air in a smaller space. This rotary motion is caused by the drive shaft of the compressor in the engine of the automobile.
- The scrolls, the air pressure and temperature are at their greatest near the center of the scrolls before the air is released through the center to the discharge port.
- The swirling motion of the scroll helps reconstruct the gap between scrolls and thus draws in more air through the intake valve which helps in the repetition of the cycle.
Oil Free Air Compressor
While the oil-free air compressor operates, the piston in the cylinder compresses the air, thus raising its pressure to the desired level. As with most oil free air compressors, they are usually piston compressors or rotary screw compressors but in an oil-less design.
Piston compressors employ piston cylinder combinations to compress air, the seals of which may be piston rings and other restricted gaps between moving parts rather than the splashed oil. Due to the absence of oil, it is impossible for it to foul the compressed air stream in any way. Rotary screw compressors use two rotors that operate in a manner where they compress the air as well as transport it. High precision rotors and the high level of accuracy in the production of the rotors and the housing allow the system to run without any oil for lubrication. Certain types of rotary screw compressors even use a small amount of clean water for cooling purposes in order to minimize wear to the rotors.
Advantages of Oil-less Air Compressors
There are several significant benefits that oilless air compressors offer over traditional oiled units:
Oil-Free Air
There is no requirement for de-oiling of the air and hence, the presence of oil carryover or oil contamination is not an issue. This makes less units of oil more suitable for use in applications that need very clean, oil-free air like food and beverages, medicine manufacturing, electronics, hospitals, artwork preservation and laboratory.
Reduced Maintenance
As there is no oil present in the system it means that the amount of maintenance work that needs to be done is less in total. The problems, which come with the use of oil lubrication such as oil change, oil filter change, the formation of sludge on lubricated components, and other service problems, are done away with.
Better Air Quality
Besides having no oil in the medium, the air stream is also likely to be purer and less moist due to lack of oil to attract moisture or particulate contaminants. This leads to improved quality of the compressed air as mentioned below.
Lower Operating Temperatures
Lower operation temperature without contact with oil makes less contact with components and therefore gives more service time to the compressor.
Environmentally Friendly
Oil free units are less risky environmentally than those that use oil since it poses the danger of contaminating the environment, spilling over, creating difficulties in disposal as well as posing other associated risks. It is also environmentally friendly since their operation does not emit any pollution into the environment.
Flexible Installation
From this point of view, an oil free compressor does not require oil to leak or spill and as a result, it can be mounted in any position and at any place without posing any threat of polluting the floor or the space. They are designed to be user friendly and easy to install in different ways and positions.
Conclusion
It is important to note that with the engineering and fabrication techniques involved in precision manufacturing, non-lubricated compressor designs are capable of delivering high levels of reliability and clean, dry air that is free of oil. Their first-dollar cost proves to be less costly in terms of operating expenses and contaminate threat as opposed to compressor styles utilizing oil.
