Air Compressors: Guide to Buying the Best Compressor

Transmission Types

The transmission in an air compressor refers to the mechanism used to transfer driving energy from the main engine to the compression unit that compresses the air. This transmission is necessary so that the engine can provide the power needed to operate the compressor.

• Belt Compressors
  Belt compressors are ideal for producing compressed air with non-constant peak loads. This type of compressor is designed for more professional uses and suits more demanding users.
  Belt compressors work via a belt that connects the engine to the pumping unit, allowing the engine to provide the energy needed to compress the air.
  These compressors are commonly used in various professional applications such as mechanical workshops, industrial plants, and commercial facilities.
• Coaxial Compressors
  Coaxial compressors are a type of compressor with direct engine transmission. In this type of compressor, the engine and the compression unit are arranged coaxially, meaning aligned one inside the other. In other words, the engine and the compression element are mounted on a single shaft, with the engine located inside the compression element or vice versa.
  This coaxial design allows for a compact construction of the air compressor, reducing the overall footprint of the unit and, consequently, its weight. These factors, along with easy maintenance and less wear, make this type of compressor commonly used for hobbyist and domestic purposes for small to medium jobs.

Difference Between Screw Compressor and Piston Compressor

Screw compressors and piston compressors differ in their operating principles and are suitable for different applications.

• Screw Compressors
  Screw compressors use two screw rotors that mesh together to compress the air. These compressors are known for their superior energy efficiency compared to piston compressors, especially for applications requiring a continuous and constant airflow. Additionally, screw compressors are generally more compact and require less maintenance than piston compressors. They are ideal for industrial applications that need a constant production of high-pressure compressed air.
• Piston Compressors
  Piston compressors use one or more pistons inside cylinders to compress the air. Although they are usually cheaper to purchase than screw compressors, they are suitable for applications requiring higher pressures or intermittent airflow. However, they tend to be noisier and require more maintenance than screw compressors.

Fundamental Features of a Compressor

When choosing the most suitable compressor for professional, semi-professional, or industrial use, depending on your needs, it is essential to analyze three main features: air pressure, airflow, and compressor power.

• Air Pressure
  The air pressure of a compressor is the maximum pressure at which it can operate and refers to the force per unit area with which the air or gas is compressed inside the compressor itself. This value is indicated in bar (or in psi or kPa) and is crucial as it determines the compressor's ability to power pneumatic equipment or other tools that require compressed air at a certain pressure to function correctly.
  Higher pressure means the air has been compressed more intensely and has greater potential energy, while lower pressure indicates less intense compression.
• Airflow
  Airflow is the amount of compressed air the compressor can generate or deliver in a given time interval. It is measured in volumes per unit of time, such as liters per minute (L/min) or cubic meters per hour (m³/h), and is influenced by several factors, including the compressor's power, its design, rotation speed, and the size of internal components.
  It is important to choose a compressor with airflow suitable for the specific application's needs, so it can provide enough compressed air to meet the demand of the devices or equipment being powered.
• Engine Power
  The power of an air compressor can be indicated in different ways, depending on measurement conventions and manufacturer specifications. The most common units of measurement are watts (W) and horsepower (HP).
  Choosing an air compressor with adequate power is essential to ensure optimal and reliable performance in various applications. The compressor's power directly affects its ability to generate and maintain the air pressure needed to power pneumatic tools or meet the specific application's requirements. If the compressor is undersized for the required workload, it may not be able to provide sufficient pressure or maintain the necessary airflow, compromising efficiency and productivity. On the other hand, an oversized compressor might be costly in terms of initial investment and energy consumption, as well as unnecessarily occupying space. Therefore, carefully evaluating the compressor's power based on the application's specific needs is essential to ensure efficient, economical, and reliable long-term operation.

Main Components

• Engine
• Pumping Unit
• Air Filter
• Cooling System
• Tank
• Pressure Switch
• Pressure Gauge
• Pressure Regulator
• Air Outlet Fitting
• Condensate Drain Valve

Among these, it's important to pay special attention to:

• Pumping Unit
  The pumping unit is the most important part of the machinery as it determines the pressure and air production capacity (L/min). Pumping units can be single-stage or two-stage.
• Air Tank
  Choosing a tank for an air compressor depends on several factors, including the compressor's size, the type of application, the required pressure, and the available installation space.
  Tanks can vary in size and configuration, but the two main types are vertical compressors, used when horizontal space is limited, and horizontal tanks. The latter are the most common and are often used in environments where a lower profile is preferred or when the tank needs to be mounted on a vehicle or mobile application.
  There are also tankless compressors, also known as "tank-free" compressors. In these compressors, the air is compressed directly and delivered to the user without being stored in a tank. Since there's no storage tank, the air is delivered immediately without needing to be accumulated first, making tankless compressors ideal for applications requiring a continuous supply of compressed air without interruptions.

Difference Between Single-Stage and Two-Stage Compressor

• Single-Stage Compressor
  have only one compression stage, meaning the air is compressed once before being discharged. This type of compressor is often used for less demanding applications in terms of pressure and airflow.
• Two-Stage Compressor
  have two compression stages. The air is initially compressed in the first stage and then passes through a second stage for further compression levels before being discharged. This type of compressor is typically used for applications requiring higher pressure and airflow, such as in industry, process applications, and larger compressed air systems. In general, two-stage compressors can achieve higher pressures than single-stage compressors but may also be more complex and costly to design, install, and maintain.

Types of Compressors

• Silenced Compressors
  A silenced air compressor is a type of compressor designed to significantly reduce the noise level produced during operation. This type of compressor is equipped with special noise-reduction devices, such as silencers, sound-absorbing coatings, and acoustic insulation, which help attenuate the sound generated by the compressor during air compression.

• Long Life Compressors
  "Long Life" air compressors are compressors designed and built with particular attention to the durability and reliability of their components and materials. Thanks to low speed, reduced oil consumption, and less friction, Long Life air compressors have greater longevity and resistance to wear. These compressors are designed to operate continuously or with a very high duty cycle without significant performance deterioration over time.
  These compressors are often chosen for applications where operational continuity is essential, such as in industry, crafts, mechanical workshops, and sectors where compressed air is a critical component of the production process.

• Oil Less Compressors
  An oil-less compressor is a type of air compressor designed to operate without the need for oil lubrication. This type of compressor is commonly used in environments where oil presence could contaminate the compressed air, such as in the food, pharmaceutical, or electronics industries.

• Compressors with Dryer
  The dryer is a device designed to remove moisture from the compressed air. This is important because moisture in compressed air can cause problems like corrosion, rust, excessive wear on pneumatic tools, and loss of application efficiency. Additionally, compressed air with high humidity requires more energy to compress and treat. By removing moisture with a dryer, you can improve the overall energy efficiency of the air compression system.

• Medical Compressors
  A medical compressor is a specific type of compressor designed and built to meet standards and regulations concerning compressed air used in medical and healthcare settings. These compressors are designed to ensure the highest purity of compressed air, eliminating any contaminants that could compromise patient safety or the sterility of medical equipment. The main distinguishing features of a medical compressor are advanced filtration systems, high-quality construction materials resistant to contamination, and quiet operation to minimize disturbance in sensitive environments.

• Compressors for Breathable Air
  Breathable air compressors are devices designed to produce high-quality compressed air that can be used with total safety for human respiration. These compressors are primarily used in environments where it's necessary to provide clean and safe air for breathing, such as diving centers for underwater diving, sea rescue operations, firefighting services, and rescue operations in hazardous environments.

• Engine Compressors
  Generally, compressors have single-phase or three-phase power supply, but there are also compressors powered by combustion engines specifically designed for use in areas where it's not possible to connect to the electrical grid. This type of compressor is called engine compressors.
  Engine compressors are designed for use in harsh conditions and where, as mentioned, there's no possibility of electrical connection. This type of compressor is ideal for professionals in the construction, industrial, craft, and even agricultural sectors.