Dense Phase Conveying

Dense phase pneumatic conveying systems are used when the product quality is of highest interest. They minimize changes in bulk densitiy and particle size distribution and limit seggregation effects.

The absence of rotating parts in pressure vessels reduce maintenance cost, the advantageous ratio of product to conveying gas make our systems energy efficient.

Pressure vessels are utilized within dense phase conveying systems to introduce the bulk solids into the pipeline. Contrary to using rotary valves, the system has no leakage and is absolutely gas tight.

This allows a high pressure range from 1barg up to 6barg or more. The high loading and low velocity leads to gentle conveying and low wear of pipeline and receiver. 

With dense phase conveying systems, the transport of bulk solids is possible from short distances up to long distances of several hundred meters.

Principle of Operation

A pressure vessel is loaded from silo big-bag unloader or process equipment, i.e. mixer. The operation cycles include the refilling, applying of pressure and conveying of bulk material as plug or dune to the receiving hopper.

The solids are conveyed as a continous layer with the "DenseFlow" PHF conveying system operating at moderate gas velocities of 15-25 m/s.

The solids are conveyed in moving bed flow as a dune on the bottom of the pipeline with the "DenseFlow®" PHF conveying system operating at moderate gas velocities of 10-25 m/s.

The solids are conveyed as a pulsed plug with the "PulseFlow" PTA conveying system operating at low gas velocities of 4-12 m/s.

The solids are conveyed as a pulsed plug with the patented "PulseLine" PTA PL conveying system operating at low gas velocities of 4-12 m/s over an extended conveying distance and with maximum process safety with exernal air injectors equipped along the pipeline.



Area of application

  • Instant products from spray drier
  • Segregration free transport from mixer to filling lines
  • Gentle transport of chemical products from process to loading area
  • Reactor loading
  • Direct batch weighing on load cell into pressure vessel
  • High capacity material handling (e.g. 150 m3/hr)
  • Filter ash conveying
  • Conveying under nitrogen without recirculation
  • Slow velocity truck unloading with mobile dense phase air manifold


  • Very gentle handling of fragile products
  • Minimized wear of pipeline and bends
  • Minimized seggregation of mixed products
  • Absence of rotating parts eliminate the danger of metal contamination and reduce maintenance costs
  • Gas and dust tight system with no leakage air
  • Batch weighing of pressure vessel possible
  • High solids loading leads to smaller pipe diameter
  • Control of air volume with Gericke nozzle
  • Low gas consumption reduces the required filter area on receiver  leading to                                low operation costs
  • Long conveying distances up to 500m and capacity up to 150 m3/hr 
  • Ready to use graphical pneumatic conveying controller STP 61 with TCP/IP interface


  • Pressure vessels according PED 2014/68/EC
  • The pressure vessels are available in carbon steel or stainless steel
  • Available standard volumes are from 20 l to 2'700 l
  • Different executions available: Hygienic design for food applications, as well as robust design for abrasive products.
  • Different bottom cone angles suited for full discharge also for difficult flowing products
  • Abrasion resistant outlet cone