A pump or a compressor is required to move hydraulic fluid through a system. Both achieve this purpose, albeit in unique ways. Pumps move liquids or gases. High pressure compressor in Pakistan only transport gas due to their intrinsic compressibility. They both have substantial pressure rises.

Compressor Types

Compressors are used to transport air into a chamber. Most compressors work by pumping air into a chamber to compress the air. Air is pumped into the cylinder chamber by pistons and one-way valves. Most commercial compressors are one- or two-stage. Single-stage compressors are utilised at pressures 70-100 psi. Two-stage compressors are utilised at pressures above 100 psi. Defined as using only one side of the piston, while double-acting uses both. When a compressor's pressure limit is reached, it shuts off. The air will be kept until it is needed for kinetic energy.

Compressors transform an electric or gas motor's power into compressed air. The compressor compresses air and raises tank pressure. (Air Compressor Geeks photo)

Helical screws guide air into rotary screw compressors. Much like a piston, the screw moves and compresses air. Most rotary-screw air compressors are single-stage helical or spiral-lobe oil-flooded. These oil-cooled compressors have no valves. The oil seals the internal clearances, and because the compressor is cooled internally, the operating temperatures are safe.

Friction causes heat loss in rotary screw compressors. Rotary screw compressors require regular cooling to function properly. (Image: Air Compressors Guru)

Centrifugal compressors are commonly seen in negative displacement air compressors. A rotating impeller creates centrifugal force to accelerate and decelerate collected air, pressurising it. A centrifugal compressor's inlet guide vanes can be changed for capacity. Closed guiding vanes lower volumetric flow and capacity.

Centrifugal compressors use shaft seals and vents to keep operating gears and mechanical parts from getting wet. (Photo: Direct Industry)

Pump Types

Positive displacement pumps and centrifugal pumps are the two main types. Positive displacement pumps force a constant volume of fluid into a discharge pipe. They produce consistent flow regardless of discharge pressure. For safety, positive displacement pumps incorporate a relief or safety valve on the discharge side. An open discharge valve causes a positive displacement pump's line to burst, causing damage to the pump. Positive displacement pumps include reciprocating, power, steam, and rotary pumps (gear, lobe, screw, vane, regenerative or peripheral, and progressive cavity).

The retract stroke forces suction valves to open, allowing fluid into the cylinder. The forward stroke forces liquid into the discharge valve. A single cylinder's flow spans from maximal in the middle to zero at the ends. Using two or more cylinders out of phase with each other reduces energy losses. Diaphragm pumps, on the other hand, flex the diaphragm in the pumping  Sublimation printer in pakistan cylinder via the plunger. Used for hazardous and poisonous fluids, diaphragm pumps