Bulkflow Heat Exchanger: How It Works
The Bulkflow Heat Exchanger heats or cools powder and bulk solids by combining a welded plate heat exchanger with mass flow design.
The equipment includes a vertical assembly of welded stainless steel heat exchanger plates called the ``plate bank,`` and a mass flow discharge feeder mounted below the plate bank. Free-flowing bulk solids pass slowly through the vertical channels between the heat exchanger plates. Heat transfer fluid flows inside the welded stainless steel plates to heat or cool the material as it passes through. A control system maintains product level in the inlet hopper for even distribution during operation.
Mass Flow of Powder and Bulk Solids
The product moves slowly through the equipment to achieve uniform heating or cooling. The heat exchanger plates are spaced to ensure reliable flow. With our mass flow design, all of the material is in motion with uniform velocity over the full cross-section of the heat exchanger. A specially designed discharge feeder is mounted below the plate bank to control the discharge rate of the product and to achieve mass flow through the pressure equipment. This results in a ``first-in-first-out`` sequence, an important element in the design of the Bulkflow Heat Exchanger.
Heating or Cooling: Powder and Bulk Solids
For cooling, water or glycol heat transfer fluid is circulated through the heat exchanger plates. For heating, steam is commonly used, but hot water or thermal oil can also be used effectively as a heat transfer fluid. For maximum efficiency, the heat transfer fluid flows counter-current to the product flow. The vertical configuration of heat exchanger plates provides a large heat transfer surface in a compact unit. Unlike rotary drum or fluid bed processors where air is in contact with the product, this indirect method of heat transfer maintains product quality while eliminating the need for costly air handling equipment.
Multiple plate banks can be mounted in a single piece of equipment. This configuration operates with a higher thermal efficiency by offsetting the heat exchanger plates in each bank.
In warm climates with high relative humidity, low volume dry air is injected to prevent condensation. This reduces the dew point of the entrained air inside the heat exchanger.
Mass Flow Discharge Feeder
The Bulkflow Heat Exchanger is engineered with a mass flow discharge feeder that regulates the product feed rate through the equipment. The discharge feeder is mounted directly below the plate bank and material is fed uniformly over the entire cross section of the heat exchanger.
There are a number of alternative discharge feeders that can be selected, depending on the flow characteristics of the material: the vibrating feeder, mass flow hopper and gate feeder.