Types of Hydraulic Pumps | Mechanical | Piping

Understanding Different Types of Pumps

External Gear Pumps

• An external gear pump consists of two gears that rotate against each other, with one gear driven by a motor. The driven gear is known as the drive gear.

• As the gears rotate away from each other, they create a vacuum at the inlet port, allowing fluid to flow into the pump and be trapped in cavities formed by the gear teeth.

• Advantages include high speed, pressure capabilities, quiet operation, and compatibility with various materials; however, bushings can wear out over time.

Internal Gear Pumps

• Internal gear pumps feature an inner gear within an outer gear. The inner gear has outward-protruding teeth while the outer has inward-protruding teeth.

• Fluid is trapped between these gears and transported from intake to discharge through a crescent-shaped divider that separates these sections.

• They provide smooth flow but come with disadvantages such as higher costs and limited size range.

Rotary Vane Pumps

• A rotary vane pump operates using vanes mounted on an off-center rotor shaft. These vanes slide in and out to maintain contact with the housing as they rotate.

• This design creates varying chamber sizes for fluid entry and exit; larger chambers allow fluid intake while smaller ones force it out through discharge ports.

• Advantages include handling low viscosity fluids at higher pressures; however, they are complex and unsuitable for high-pressure or high-viscosity applications.

Piston Pumps

• Swash plate piston pumps convert rotational motion into reciprocating motion via a swash plate angled against pistons in a cylinder block.

• During rotation, pistons create a vacuum to draw fluid in during half of their cycle while expelling it during the other half due to spring action maintaining contact with the swash plate.

• Piston pumps are designed for efficiency across various pressures due to closer internal fits compared to other types.

Radial Piston Pumps & Hand Pumps

• Radial piston pumps have pistons arranged like spokes around a central cam that forces them down into a cylinder block for fluid discharge while springs assist retraction during intake strokes.

• These pumps operate quietly under high loads at low speeds and are highly efficient.

• Hand pumps serve where power sources aren't available; typically piston-type designs working between check valves offer double acting functionality for better efficiency.