A reciprocating air compressor has many features, including a crankshaft, pistons, cylinders, valves, intakes, and outlets. The compressor works more like an internal combustion engine and has various design similarities. A reciprocating compressor is a positive displacement compressor that uses reciprocating piston action to compress air. You’ll encounter different types of compressors with slight differences in how they work.
Components of a Reciprocating Compressor
You need to know the components of a reciprocating air compressor to understand how it works. A standard compressor features an external motor, crankshaft, pistons, cylinders, and intake/outlet valves. The external motor drives the crankshaft, which drives pistons inside a cylinder. Intake valves let air into the piston cylinders.
The pistons move in a reciprocating fashion and compress the air. An outlet valve then releases compressed air. The compressed air will lose its pressurization and expand to normal volume if not used immediately. You can attach the compressor to a storage tank to keep the compressed air pressurized. Compressor motors can use electricity or fuel like gasoline.
How Reciprocating Compressors Work
Compressors work by drawing air into an enclosed cylinder with a piston. When a piston moves outward, it creates a vacuum that opens the air intake valve and draws air into the cylinder. The piston then moves inward, compressing the air and forcing it through the outlet for immediate use or storage. A typical air compressor has a crankshaft driving two or more pistons. You’ll encounter the following types of reciprocating compressors:
- Single-Acting Air Compressors: The compressor uses one side of the piston to compress air, while the other side is attached to a crankshaft.
- Double-Acting Air Compressors: Both piston sides are used to compress air. When the piston compresses in one direction, it draws air into the opposite chamber.
- Single-Stage Air Compressors: Air compression occurs in a single cylinder. The air is then released through the outlet for storage or immediate application.
- Double-Stage Air Compressors: Air compression occurs in two stages. The first piston compresses the air partway and pushes the air to the second piston for further compression.
Reciprocating Compressor Basics
Standard reciprocating compressors have five basic components that encapsulate how they work. The components include intake cycles, unloading processes, duty cycles, cooling, and lubrication. Intake cycles happen when the piston pushes downwards, creating a vacuum that opens valves at the top section to draw air from the atmosphere. The piston then moves up, pressing the air into a smaller space to build pressure and overwhelm the discharge valves.
Duty cycles are determined using the time your compressor stays loaded and how long the machine runs when unloaded or off. Manufacturers design reciprocating compressors to work at specific full-load times. The compressor should remain unloaded most of the time. Choose the right size compressor to avoid increasing the load time and reducing the efficiency and longevity of your machine. Compressors also use a pressure control device to control the unloading process.
The pressure governor senses if the storage tank has reached a predetermined threshold and signals the compressor to unload. If the air pressure falls below a predetermined threshold, the governor signals the compressor to restart the compression cycles. Reciprocating compressors also use cooling lubricants to regulate motor/engine temperatures. Moving parts may also need lubrication to reduce heat and friction. The lubricating fluid is recycled within the unit.
Heat, Pressure, and Noise
Reciprocating compressors feature moving parts and produce more heat than rotary air compressors. Lubricating oils can reduce friction and heat. Air compressors also feature a fan that helps to reduce the temperatures. Reciprocating compressors produce more pressure than rotary screw compressors but not as much as centrifugal compressors. Noise isn’t usually a factor, but double- or triple-acting reciprocating pistons can provide distracting decibels.
Reciprocating compressors are a tad louder than rotary screw models. Because of the touching parts, reciprocating compressors need careful monitoring and maintenance to slow down the wear and tear. The heat, pressure, and noise levels will depend on the type of compressor, material quality, and specifications like speed or operation. You should follow the manufacturer’s instructions and recommendations to keep your compressor in top shape.
Premium Reciprocating Air Compressor
A reciprocating air compressor suits many applications and offers more benefits than rotary screw and centrifugal compressors. You should stick to top models from reputable brands. Quality constructions and materials will give you more years of operation and less frequent breakdowns. Follow the best practices to keep your compressor working efficiently throughout the years.