Dense Phase Pressure Conveying - Dense Phase

Dense phase pressure conveying systems use compressed air at above 1 Barg (0.8 - 0.9 possible dependent on powder and convey line) to push materials from a pressure vessel, sender unit or pressure pot through a pipeline to a destination where the air and product are separated.

The product extrudes through the pipeline, initially at a low velocity, and gradually accelerates towards the destination.

Specifications

  • Convey Rates:               high, up to 100 tonnes/h or higher. 
  • Convey Velocities:         1–10 m/s. 
  • Convey Distances:         from short distances to greater than 500 m. 
  • Air mover:                    compressor (screw, rotary, reciprocating). 
  • Operating Pressure:       <8 Barg. 
  • Material Air Ratios:         high, up to 150 kg/kg.

    NB: All values are approximate: please contact GEA for advice about how to convey your product.

Options

To optimize the system, various techniques can be used to reduce compressed air consumption and cost, and additional options for specialized applications are available: 

  • air injectors to fluidize materials to reduce friction 
  • pulsed air injection to break up the product flow into discrete slugs 
  • line boosters to assist conveying 
  • vibration to loosen cohesive powders prior to conveying 
  • twin vessels to provide continuous conveying 
  • inline sampling, delumping, metal detection and magnetic separation systems 
  • stepped lines to reduce terminal velocities, abrasion and degradation 
  • stainless Steel construction for sanitation or corrosion resistance 
  • demountable and polished designs to USDA 3A standards for ease of cleaning.
 

Application

Dense phase pressure conveying is particularly suitable for conveying high capacity materials over long distances to multiple destinations. Most systems include several air control valves and the high pressure compressed air supply — along with correct fluidization — is able to overcome any pressure drop that could be generated by difficult materials. Also providing controlled conveying for friable materials, the lower convey velocities can extend the service life for systems conveying abrasive materials as well.

Systems

Systems generally operate on a batch basis as follows:

  • fill the sender unit with product to be conveyed
  • pressurize with compressed air
  • open the discharge valve until the product has been conveyed out
  • close the discharge valve and refill the vessel.

Valves and sensors are used throughout the process to control the air pressure and velocity and ensure correct fluidization and trouble-free product conveyance.