Fans

fans
Fans are used to transport gases under low pressures (less than 0.5 psi). Fans can be separated into two major categories: centrifugal and axial flow. Air is discharged radially from centrifugal fans and axially from axial-flow fans.

Compressors

pictures of compressors
Compressors are used to increase the pressure of a fluid. The main type of compressor is the rotary compressor, meaning a rotary device is used to compress the fluid. Reciprocating and centrifugal compressors are the most common.

Aerators & Diffusers

Aerators & Diffusers on the water
Aerators and diffusers are used to increase the gas content of a liquid, typically oxygen in water. Diffusers are a specific type of aerator in which air is diffused through a surface and into the liquid itself. The name does not refer to the process of diffusion through the liquid.