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Why Dense Phase Conveying

When considering the transfer of dry bulk materials (powdered or granular), dense phase pneumatic conveying offers an option with low energy consumption, minimal installation costs, low maintenance requirements, and minimal downtime if maintenance is required.

Dense phase systems convey material at velocities slower than any other form of pneumatic conveying, and the minimal moving parts within a Dense Phase system means less downtime, and lower maintenance costs.  The material velocity in a Dense Phase system averages between 500 and 1000 Ft. / Min., that’s up to 10 Times slower than other forms of pneumatic conveying (ie. Dilute Phase).  Low average material velocity means pipeline components in a Dense Phase system will have much longer lifespans, and overall wear and tear on the system will be minimized.

 

Dense Phase vs. Dilute Phase Pneumatic Conveying

When comparing dense phase to dilute phase, the greatest difference from a component wear standpoint is that the material within a dilute phase system moves at a significantly higher velocity.  The material being conveyed in a dilute phase system relies on material suspension, which means that the material within a dilute phase system must be conveyed at a velocity fast enough to insure the material remains “suspended” throughout the convey pipeline.  The high volumes of air/gas needed to insure the material remains suspended in a dilute phase system can correlate to material velocities 10 times faster in a dilute phase system than those in a dense phase system.  Higher material velocities in a dilute phase system translate into increased wear and tear on all components within the conveying system.  Also, a dilute phase system has a valve that is constantly moving in order to feed material into the conveying pipeline.  The constant movement of the valve (rotary air lock) feeding the dilute phase system means that it will wear much faster than a valve in a dense phase system that might only open and close 5 times per hour of operation.

Advantages of Dense Phase over Dilute Phase Pneumatic Conveying

  • Lower Material Velocities

Because material within a dense phase system does not rely on suspension, material velocity is often 10 times lower in a Dense Phase system.  Lower velocity in a dense phase system translates to less wear and tear on pipeline components, which in turn means less downtime, lower maintenance costs, etc.

  • No Constant Moving Parts

Typically the only moving part within a JDB Dense Flow system is the Dense Flow Cone Valve used to fill and seal the pressure vessel.  Depending on a systems conveying rate the cone valve will open and close 5-45 times per hour.  In a dilute phase system a rotary valve is constantly moving during a convey cycle to feed material into the convey pipeline and air stream.  The constant movement of the rotary valve in a dilute phase systems means that it will wear and need replacement much more often than the Cone Valve in the JDB Dense Phase System.  Because the Cone Valve in a the Dense Flow system needs replacement less often maintenance costs, downtime, and spare parts inventory  are lower in a Dense Phase system.

  • Less Material Degradation

As explained previously the material velocity in a Dense Phase system is significantly lower than that in a dilute phase system.  The low velocity in a dense phase system translates into minimal to no material degradation during a convey cycle.  Minimal degradation during a convey cycle means that friable materials like Almonds, or coated materials can be conveyed pneumatically in a Dense Phase system.

  • Lower Air Consumption

While a Dense Phase system uses a higher pressure to convey material it uses a significantly lower volume of air (typically less than 25 CF of air to move 1 CF of material).  In many cases the horsepower requirements for a Dense Phase system are less than those in a Dilute Phase system conveying material at the same rate.  The lower horsepower requirement in Dense Phase system makes them more energy efficient in most cases, and the low volume of air used means less dusting and dust collection requirements.

 

Dense Phase vs. Mechanical Conveying

The advantages of dense phase conveying over mechanical conveying are seemingly endless.  A typical JDB Dense Flow dense phase system has only one moving part, compared to mechanical conveying systems like belt conveyors and bucket elevators that may have hundreds or thousands of moving parts.  The minimal moving parts in a Dense Phase system versus up to hundreds of moving parts in a mechanical system means less spare parts inventory, less mechanical breakdown which in turn will lower maintenance costs and downtime.  Dense phase conveying systems are also fully enclosed so there are no issues with dusting.  Most mechanical conveying systems are only partially enclosed or open to atmosphere; this can cause dusting and cleanliness issues throughout a facility, as well as possible red flags to the EPA.  Installation of a dense phase system is also significantly less involved when compared to most forms of mechanical conveying.

Advantages of Dense Phase over Mechanical Conveying

  • Less Moving Parts

In most JDB Dense Flow Dense Phase systems the Dense Flow Cone Valve is the only moving part within the entire system vs. a mechanical conveying system that can have hundreds.  Less moving parts means less breakdowns, less spare parts inventory, lower maintenance costs, and downtime.

  • Fully Enclosed Dust Tight Material Transfer

Dense Phase conveying systems are fully enclosed and theoretically could operate under water if all electrical components were waterproof.  This allows for safe material transfer with no dusting.

  • Lower Initial Installation Cost

A typical dense phase system consists of a pressure vessel, air and electric controls, pipeline, and pipeline components.  Routing and installation of the convey pipeline is typically the most difficult and time consuming installation process.

 

Contact our engineering department at eng@jdbdenseflow.com, 727-785-8500 x203 to speak with an engineer about the advantages of a Dense Phase conveying system.

 

J.D.B Dense Flow, Inc. ©2014 all rights reserved

P.O Box 38, Palm Harbor, FL 34682 | P: 800-822-3569