Knowledge centre · Application

Filling high-viscosity products with particles

Chilli sauce, bean paste, fruit fillings and prepared-dish sauces are the products where filling equipment is most often blamed for a problem that is really a pump-principle problem.

Why piston machines struggle here

  • A narrow valve seat: solids bridge across it, so the fill is short — then a purge passes a slug.
  • Piston compression: large particles are crushed, changing both the product and the dose.
  • Dead corners: product accumulates and later releases in clumps.
  • Cleaning: disassembly to remove trapped solids adds downtime to every product change.

How rotor pump filling differs

A rotor pump moves product through a cavity that opens and closes as the rotor turns. There is no valve seat to bridge across and no piston to compress against. Displaced volume per revolution stays known, so the dose is controlled by rotation count — with a servo providing the correction.

ProductViscosityConfiguration notes
Bean paste / red bean fillingup to ≈300,000 cStSauce cut-off valve; agitated hopper
Chilli sauce with pieces20,000–120,000 cStSauce cut-off valve; low-shear transfer
Fruit jam with seeds10,000–60,000 cStGentle handling to preserve particle integrity
Prepared-dish sauce5,000–50,000 cStHeated hopper where the product sets when cool

Practical notes from application work

  • Set the hopper diameter and agitation to keep solids uniformly suspended — stratification is the most common cause of dose variation.
  • Use a cut-off valve rather than relying on nozzle geometry to stop the flow string.
  • Keep transfer distances short and avoid pumps that shear the product before filling.
  • Validate accuracy with check-weighing on the actual product, not on water.
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