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Axial piston pumps AKP (Micropumps)

BIERI Micro-Axial piston pumps AKP are very compact axial devices, with a very high volumetric efficiency, wide speed range and increased reliability, even under rough ambient conditions
We distinguish between two different designs:

  • Micropumps with 2 threaded ports, inlet and outlet
  • Micropumps with radial sealed outlet port and suction openings in housing to submerge the micropump for downhole applications
Operating pressure::up to 500 bar
Displacement:0,10 bis 0,36 cm3/rev
Speed Range:100 up to 5000 rpm  



Low piston clearance and optimized design of inlet and outlet valves:Very high and constant volumetric efficiency on a wide speed (100 up to 5000 rpm) and pressure range
Permanent lubrication and cooling through suction flow:Improved lifetime and low noise
Sturdy construction of bearings and optimal design of the suction valves:Improved reliability even in rough ambient conditions (high temperature, severe vibrations) and restricted space conditions
Modular pump system: Enables supply of standard pumps as well as special customized models

Segments & Applications

  • Directional drilling in oil & gas industry
  • Oceanographic survey devices - ROVs
  • Hydraulic tools
  • Ultra compact hydraulic systems
  • Portable power units and tools


  • Design with 3 or 5 pistons
  • Valve controlled on pressure and suction side (not usable as motor)
  • Swash shaft with large dimensioned rolling bearings
  • Rotating swash plate 

Technical Data

Hydraulic fluidMineral oil according to DIN 51524 (other fluids on request)
Fluid temperature range-20 to 80°C
Ambient temperature range-30 to 50°C
Viscosity range5 to 220 mm2/s
Max. operating pressure500 bar
Operation pressure at suction port-0.2 bar to +0.5 bar gauge pressure
Filtration (recommendation)According to NAS 1638 class 6 resp. ISO/DIN 4406 17/15/12
WeightSee table
Axial force onto driving shaftNot allowed
Radial force onto driving shaftOn request
Max. speed range100-5000 min-1
Direction of rotationAny
Installation positionAccording mounting drawing
MaterialHousing: aluminium anodised
Pump head: steel blued