Hydraulic pumps convert mechanical energy and movement into hydraulic fluid. The basic idea is very simple: a force that is applied in one position is transferred to another position using an incompressible fluid, such as oil, which cannot be compressed, but rather is shifted when pressure is applied.
The tank, hydraulic cylinder and pump comprise the three main parts of the hydraulic pump. The injection of hydraulic fluid from the reservoir into the lower cavity of the cylinder causes the piston rod to rise, which forces the fluid into the other cavity back into the reservoir. This procedure creates pressure in the chamber and extends the piston to full length. A hydraulic fluid pump in the upper chamber of the cylinder pushes the piston rod down, pushing oil into another chamber back into the reservoir, completing the cycle.
Popular types of hydraulic pumps
- Roller pumps, piston pumps and gear pumps are the first types of hydraulic pumps.
- Gear pumps - use gears to pump fluid by moving. Hydraulic gear pumps are one of the most common types of pumps. There are several advantages and disadvantages of gear pumps. Advantages: high speed, high pressure and silent operation. The disadvantages are: the use of four bushings in the liquid area and fixed end gaps.
- Rotary vane pumps are positive movements. They include a ring mounted inside a cylindrical body. There are a number of radial slots in which the sliding blades are located. A ring is attached to the case, and the blades are designed to be pressed against the inner wall of the case. Hydraulic pressure or spring force or centrifugal force while rotating the ring will cause the blade to be pressed against the wall.
- Axial piston pumps are a positive displacement. In the cylinder block there are several pistons in a ring arrangement.
- Radial piston pumps - a circular arrangement of hydraulic pistons and valves that allow you to create pressure of more than 650 bar (~ 10 000 pounds per square inch).
- Screw pumps - pumps with a volumetric working volume. Take one or more screws that rotate to carry a high or low viscosity fluid along the axis.
