Internal Gear Unit AP

The essential components of series AP external gear pumps are an aluminium alloy body and two gearwheels supported by plain bearings.

The front flange can be the SAE standard, or the British or German OEM patterns.

The various frame sizes can be combined with each other, enabling double and triple pumps to be assembled.


  • High overall efficiency thanks to optimised hydraulic compensation
  • Design and materials that guarantee excellent technical specifications and long life service
  • Optimum quality/price ratio
  • Customised models can be built for specific applications
  • Various components and accessories are available for radial/axial loads, pressure/flow control, etc.



High Pressure Internal Gear Pumps QX

The QX pumps are the 5th generation of Bucher internal gear pumps, which have proven themselves in thirty years of service around the world. The straightforward and rugged construction guarantees long service life without the need for extensive maintenance. Tandem and multiple pumps are available worldwide in more than 1000 variants.


  • High pressures
  • Low noise level
  • Long service life
  • Negligible flow and pressure
  • Insensitive to contamination


Internal Gear Pumps QXV
(for low-viscosity fluids)

The QVX is an internal gear pump for low viscosity. It can develope pressures of 300 bar with high efficiency at viscosities of around 1 mm²/s. The QXV is beeing used with great success to pump aviation jet fuels, paraffin oil/kerosene, brake fluids, Pentosin and HFA fluids.


  • Very low noise levels
  • 300 bar can be developed
  • Outstanding efficiencies
  • Long service life
  • Low pump wear
  • Low sceptibility to cavitation
  • Good emergency running


Internal Gear Pump QXP
Metering pump for polyurethane production

The QXP is an internal gear pump for metering isocyanates, polyols, additives and other fluids. Combined with a variable-speed drive, the QXP is being applied very successfully as a metering pump in the production of polyurethane.


  • precision metering with very low pulsations, even at high pressures.
  • can be used with high and low viscosities, and with variable-speed drives.



Internal Gear Unit QXM

The QXM drive unit can be used in open- and closed-loop hydrostatic drives, and can operate both as a pump and as a motor.

The QXM works as a pump to lift the load and it can recover energy when the load is being lowered.

Used as a bi-directional pump / motor (four-quadrant operation), the unit can control the complete motion cycle of a cylinder.


  • Very low noise levels
  • Negligible pressure pulsations
  • Long service life
  • Suitable for special fluids
  • 4-quadrant (fully bi-directional pump / motor) or
  • 2-quadrant operation is possible
  • Low susceptibility to cavitation