What is an Air Compressor?

Reciprocating Air Compressors

Reciprocating air compressors (also sometimes known as piston compressors) are compressors which achieve high pressure through the use of pistons controlled by a crankshaft. This works by way of air (or gas) entering the device, which is driven in a reciprocating motion via a crankshaft, and then discharged from the device. Pressures of up to 5,000 PSIG are commonly produced by multistage reciprocating compressors.

Applications include: oil refineries, gas pipelines, offshore platforms, refrigeration plants, etc. One specialty application is the blowing of polyethylene terephthalate (PET) plastic bottles. While rotary screw compressors are used for high volumes of air, reciprocating compressors are more typically used in high pressure requirements.

Rotary Scroll Air Compressors

A rotary scroll air compressor is a type of positive displacement compressor that uses two spiral-shaped scrolls, one fixed and the other moving in an eccentric orbit, to compress air. As the moving scroll orbits around the fixed scroll, it creates a series of gas pockets that gradually decrease in volume, causing the air to be compressed. The compressed air is then discharged through a port in the housing, while the low-pressure air is drawn in through another port.

Unlike other types of compressors, such as reciprocating compressors or rotary screw compressors, the rotary scroll compressor has a continuous, smooth compression process that results in very little pulsation or vibration. This makes it ideal for applications that require a steady flow of compressed air, such as in medical equipment, electronics manufacturing, and food and beverage production. Rotary scroll compressors are highly efficient and reliable, with low noise levels and minimal maintenance requirements. They are also oil-free, which makes them suitable for applications where clean air is critical, such as in the pharmaceutical industry.

Rotary Screw Air Compressors

In rotary screw air compressors, compression is achieved by way of two internal screws rotating in opposite directions, which trap and compress air between them. Equipped with an internal cooling system, these compressors require a low level of maintenance and therefore are commonly used in a number of applications. Because of this internal cooling system, these air compressors are designed for continuous use, and range in power from 5 HP up to 500 HP. Additionally, these devices can be lubricated with oil or can operate oil free for applications that require contaminant free air.

Rotary screw compressors are typically used when large volumes of compressed air are required; such applications include chilling or powering tools which require larger volumes of air to drive them e.g. jackhammers and impact wrenches. For higher pressure requirements, reciprocating compressors are typically used, which leads us to our next entry.

Rotary Vane Air Compressors

Rotary vane air compressors are a popular type of air compressor that can produce a high volume of compressed air while using relatively little energy. This makes them an ideal choice for businesses and industries that require a lot of compressed air but want to keep energy costs low. Rotary Vane Air Compressors have the lowest oil carry over (only 2 ppm). Before the vapor is introduced into the separators, a multilevel internal separation system is used. This means less downtime for your operations and more productivity overall.

These machines are compact, simple, robust and engineered to meet the most stringent of specifications. They are commonly used in a variety of applications, including manufacturing, automotive repair, construction, dentistry and packaging.

Oil Lubricated Air Compressors

Oil lubricated air compressors are machines that compress air using oil as a lubricant to help the internal parts move smoothly and reduce wear and tear. In an oil lubricated air compressor, the pump's internal components are coated in oil to reduce friction and heat, which helps to extend the lifespan of the compressor. The oil also helps to trap any contaminants that may be in the compressed air, which is important for applications that require clean, dry air. Oil lubricated air compressors often require regular maintenance to ensure that the oil is clean and at the correct level. Over time, the oil can become contaminated with dirt and debris, which can reduce the compressor's efficiency and lifespan.

Oil-Free Air Compressors

Oil-free air compressors are designed with special coatings and materials that help increase the efficiency of the compressor without requiring oil to be injected into the compressor. This eliminates the risk of oil contamination downstream. These compressors are ideal for applications where oil contamination is a concern such as in the manufacturing of food & beverages, pharmaceuticals, semiconductors, etc. Oil-free compressor technologies include rotary screw, rotary scroll and some reciprocating designs. Of these, both rotary scroll and some reciprocating are oil-less technologies.

Oil-Less Air Compressors

Oil-less air compressors are designed with special coatings that do not require lubricating oil. These compressors rely on dry compression technology, which eliminates the need for oil by using materials that are naturally self-lubricating, such as PTFE.

In terms of performance, both oil-free and oil-less air compressors can produce high-quality compressed air suitable for a wide range of applications.