Solex Thermal Science > Solex Products > SIGMA 400 Cooler > Product Details > Discharge Feeders

Sigma400 Series Bulk Solids Cooler

The feeder technology is a critical component of the heat exchanger design. The type of feeder that is selected by Solex is determined by the application.

The Solex design is based on the principles of mass flow, in which the product moves slowly at uniform velocity through the exchanger. The engineered mass flow discharge device regulates the product flow. The slow and controlled movement of the bulk materials provides two vital advantages for the final product; it results in uniform discharge temperatures and eliminates particle degradation.

Solex provides mass flow testing to ensure the optimal feeder technology is used for each individual application.

There are a number of alternative feeders that can be selected, depending on the flow characteristics of the material: the vibrating feeder, mass flow hopper and gate feeder.

Gate Feeder

The gate feeder is well suited for handling large flow rates of granular materials. It consists of a plane flow hopper with hinged gates that form two variable opening slots at the bottom of the hopper. A rotary actuator with pneumatic or electronic controls adjusts the size of the opening to modulate the discharge rate of the product.

 Gate feeder

Mass Flow Hopper

A mass flow hopper with a variable speed rotary valve is typically used when handling fine powders or discharging into a pneumatic conveying system. Hopper angles are designed based on the measured flow characteristics of the product. Mass flow tests are conducted using a Jenike Shear Tester. A vertical spool section is added between the hopper outlet and the rotary valve to alleviate any possibility of preferential flow to one side of the rotary valve.

 Mass Flow Feeder

Vibrating Feeder

The vibrating feeder operates effectively for a wide range of free-flowing bulk solids. A suspended rectangular tray with fixed internal louvers controls the material flow. Two counter-rotating vibrator motors, controlled by a variable frequency drive, apply a small amplitude of motion to the feeder. The material feed rate depends on the feeder’s vibration frequency—the higher the frequency of operation, the faster the discharge rate. When the feeder is turned off, the material’s natural angle of repose and the feeder’s louvers stop the material flow. There are no internal moving parts and therefore, no product degradation.

 Vibrating Feeder