How to Design and Size a Vibratory Feeder Conveyor Based on Application Requirements

David Strong

Similar to vibratory tables in their many uses and applications, vibratory feeders are also great problem solvers.  Well known for their ability to effective move material from point A to point B, a well-designed vibratory feeder offers flexibility to the end user to get the task done.

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Figure 1. Air Powered Vibratory Feeder Conveyor

Feeders can range from small base mounted CF-A, pneumatic powered feeders moving small quantities dry bulk material in a controlled manner to much larger base or cable supported EMF, Electro mechanical feeder, conveying literally tons of material an hour. Off the top of my head a short list of materials that Cleveland Vibrator’s vibratory feeders have worked with would include: almonds, crushed limestone, shelled corn, powdered metal, metal billets, various pipe fittings, scrap brass and bronze, crushed and shredded automobiles, hot dross and much more.

Typically, a feeder application will require the movement of some given amount of material with a known bulk density over a desired distance.

Parameters that influence the sizing and design of the equipment would include:

  1. The inlet and discharge conditions for that piece of equipment.
  2. How is the material being placed on the feeding surface?
  3. What are the dimensions of the incoming stream of material?
  4. Is the material being dumped a batch at a time or via a near continuous follow at a known rate?
  5. What’s happening at the discharge end of the unit?
  6. Does the unit feed another piece of equipment such as a belt conveyor, bucket elevator or perhaps a furnace?
  7. And of course, we look at the specific properties of the material including the bulk density and particle or part size.

A quote or design will typically start by addressing two main parameters:

  1. What is the material volume that must be moved?
  2. How far do we have to move it?
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Figure 2. EMF Electromechanical Vibratory Feeder Conveyor

How far to move obviously drives the length of the unit and may include some additional length to properly interface with the receiving equipment.  The volume of material moved per hour plus the materials bulk density will drive the width and depth of the vibratory tray.  If the equipment that passes the material onto the vibratory feeder doesn’t restrict the specification of the feeder’s width, we then look at the volume and density of the material. Using past experience and product testing, an estimated linear velocity for the material is used to calculate a cross sectional area for the material flow based on the rate per hour and bulk density.  Once we’ve calculated that cross sectional flow area, we factor in the tray width and see what happens to our depth of material on the vibratory tray.  If everything looks good and makes sense for the specifics of the application we’ve arrived at the final size and specifications for the vibratory feeder.

A well designed and properly installed vibratory feeder is a thing of beauty!  Simple and effective, it lives to move material from point A to point B.  These feeders are mechanically very clean and virtually maintenance free. Small air powered CF-A units are driven by a variety of appropriately sized robust and quiet air cushioned pneumatic piston vibrators.  Supply clean and lubricated air to these units and they’ll provide dependable service for a very long time.  If the feeder is powered by a pair of Cleveland Vibrator’s rotary electric vibrators, some of which are permanently lubricated, the equipment will perform its task of effectively moving material for years to come.

Without a doubt the most common use for a vibratory feeder is to move material as described above, but a number of our customers also use vibratory feeders to add or spread a dry material onto the surface of their products.

When conveying dry material of a consistent density and particle distribution, vibratory feeders can effectively be used to meter one product onto the surface of another product.

Figure 3. How to adjust eccentric weight on Rotary Electric Vibratory Motor

We have a number of customers who use our EMF units to apply a layer of dry product onto the surface of a moving product as it passes under the feeder.  By adjusting the operating speed of the vibratory motors and/or the eccentric weights, operators can dial in the right combination of frequency and force to apply a consistent and repeatable volume of material onto the surface of their product to successfully meet their rate requirements.

I recently visited a potential customer’s facility to review such an application.  The company is looking to improve on their current method of applying a granular product onto the surface of their raw product as it moves down a conveyor belt.  Currently, they have a hopper mounted above the conveyor and a rotating knurled cylinder on the bottom opening of the hopper.  Rotating the cylinder is intended to permit the material to drop onto the moving product.  Unfortunately, the material size varies a bit and that different sized material is important to the process, but it also creates a problem for the current process.  Jams and inconsistent spreading of the product have a negative impact on the finished product.

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Figure 4. Cable-Suspended Vibratory Feeder Conveyor

After looking at their current process, I suggested the use of a cable suspended vibratory feeder.  Due to the open nature of the feeder, different sized particles can be easily conveyed without concerns of jamming.  By adjusting the operating speed and force output of the vibrators, the feeder can spread a consistent layer of the secondary product edge to edge on to the material below.  Coupling the feeder with a small storage hopper would ensure that the feeder has a plentiful supply of material, critical in making sure the feeder maintains a consistent and repeatable thickness of material on the vibratory feeding surface, resulting in a well control and regulated volume of product conveyed by the feeder. We’ll see where this project goes with time.

It’s worth keeping in mind that a properly sized, designed and installed vibratory feeder is a real problem solver.  Feeders can successfully move a very wide variety of products from point A to B plus can be used to meter or spread one product onto another.  For more information on Cleveland Vibrator’s complete line of electric and pneumatic powered vibratory feeders, please contact our Sales Team.

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