Ball valve pump KOV 
    Highly Reliable Piston Pump with Indirectly Operating Balls
    Part of the KOV series which is characterized by its straightforward
  design and high reliability; the suction and delivery cylinders of
  this piston pump are connected by indirectly operating balls. Omission
  of actively driven elements results in a good value pump with the
  maximum availability. Pasty materials such as mortar or Bentonite,
  even with a content of foreign substances up to 1” (20 mm) in size can
  be conveyed without any difficulty with a pumping pressure up to
  1305 psi (90 bar) and an output of up to 78.5 yd³/hr (60m³/hr).
Depending on specific individual demand, the balls and valve seats
  can be supplied in different materials and coatings and a maintenance
  aperture permits easy and rapid replacement of the valve balls.
  