Solex Thermal Science > Solex Products > SIGMA 400 Cooler > How It Works > Dried Biosolids

Sigma400 Series Bulk Solids Cooler

1 SLOW & CONTROLLED PRODUCT FLOW
Dried biosolid pellets pass slowly downward between a series of vertical hollow heat exchange plates.
Why It's Better

2 INDIRECT PLATE COOLING
Cooling water flows through the plates to cool the material by conduction.
Why It's Better

3 MASS FLOW TECHNOLOGY
The mass flow discharge feeder creates uniform product velocity through the cooler and regulates the product flow rate.
Why It's Better

4 VERTICAL CONFIGURATION 
Dried biosolids pass through the vertical cooler by gravity.
Why It's Better

Sigma 400: How It Works

Why It's Better

The slow and controlled movement of the pellets by gravity through the heat exchanger prevents product breakage and the generation of fines in the final product going to storage which reduces the potential for smoldering.

Why It's Better

The unique indirect plate cooling design means air is not used in the cooling process. This design is superior and results in many important benefits for cooling dried biosolids.

  • Emissions, dust, fines and odors are eliminated because air is not used to directly cool the product. There is no need for additional dust removal or odor control.
  • Installed capital costs are reduced due to the elimination of costly and unnecessary air handling equipment such as large diameter air ducting, motors, fans, scrubbers, chillers, etc.
  • The plates are configured to enable easy access for inspection and cleaning. The design includes large access doors that provide easy entry and make it possible for single plates to be accessed, repaired or replaced.
  • It is ultra efficient, using up to 90% less energy than technologies requiring the use of air

Why It's Better

Mass flow design means the pellets move with uniform velocity through the heat exchanger. This feature, combined with long residence times (typically 5-10 minutes), enables even temperature distribution as the product passes through the heat exchanger, producing remarkably stable and uniform final product temperatures.

Why It's Better

The vertical configuration makes this design both compact and modular.  

  • The compact installation footprint makes this design easy to integrate into dryer systems. The Solex cooler can discharge directly to a dense-phase pneumatic conveying system.
  • The clever modular design means that additional heat exchanger plate banks can be stacked if increased cooling capacity is required in the future