If you are having any concern related to hydraulic motors, you need to know about hydraulic gear pumps. The gear pump is a machine for the conveyance of liquids as well as for the power transmitting drive of hydraulic motors. It is a subspecies of the positive displacement pump. The gear pump basically consists of two components:
- Housing with inlet and outlet
- Two gears (one of which is driven).
These pumps are used extensively in the petrochemical industry, the chemical industry, paint and ink industries, etc.
Types of Hydraulic Gear Pumps:
Depending on the arrangement and size of the gears, a distinction is made between different types of Hydraulic Gear Pumps:
- External Gear Pump: In the case of the external gear pump with involute toothing, the medium to be pumped is transported in the spaces between the teeth and the housing. The pump is robust and inexpensive due to the simple construction.
- Internal and Gerotor Pump: In the internal gear and gerotor pump, the driving gear runs eccentrically in the internal toothing of a toothed ring. In the case of the gerotor pump, the medium is conveyed through the space- changing displacement space between the tooth spaces.
- Sickle Pump: In the sickle pump, the medium to be delivered is conveyed in 2 spaces between the tooth gaps of the two gears, whereby the teeth are sealed by a sickle. Both designs also differ in the size ratios of gear and ring gear. While the outer ring of a gerotor pump has exactly one more tooth than the inner wheel, the internal or sickle pump has significantly more teeth outside than inside.
- The Screw Pump: This is a positive displacement pump in which the shape of the rotating displacer is similar to a spindle screw. It is the helical variant of the gear pump and is one of the screw compressors.
Working Mechanism of Hydraulic Gear Pumps:
A hydraulic gear pump consists of two or more counter-rotating rotors and a housing that encloses the rotors. The rotors are formed with regular, thread-shaped profiling and engage gear-like in one another. The cavities, which are formed by these three construction elements, form the delivery chambers for the pumped medium. During rotor rotation, they migrate in one machine direction and convey the medium from the suction side (inlet) to the pressure side (outlet). Due to the helical design, the noise is lower compared to straight-toothed gear pumps. With a uniform thread pitch, the expression of the cavity (volume) is not changed during the rotor rotation. A change in volume (compression) can be achieved by continuously changing the thread pitch of the rotor profile over the rotor axis or by stepwise changing the thread pitches in sections on the rotors. This type of pump is particularly suitable for incompressible, also viscous media for generating high pressures. Applications include: Increasing the pressure of water to the back pressure osmosis or as a pump for the oil supply in hydrostatic bearings. Since the mid-1990s, this type of pump has also been used primarily for fuel pumps in the passenger car and commercial vehicle sector. For some years, this pump type (oil-cooled type) has also been used for vacuum generation.
Applications of Hydraulic Gear Pumps:
These pumps are used for the following purposes:
- Metering pump in the plastics industry for liquid color dosing under pressure.
- Drive means for hydraulic force transducers (hydraulic motors or single / double-acting lifting cylinders) in construction machinery, tractors and in craft and industry, in particular, vehicle construction.
- Circulation of cooling circuits.
- Conveying means as an oil pump in the internal combustion engine, common rail high pressure pump (automotive diesel injection) of the automobile and in oil burners; Promotion of highly viscous liquids (melts), which are to be conveyed at high temperatures and under high pressures.
It can be concluded that hydraulic gear pumps are highly significant and used extensively for a wide range of purposes.