How Are Bulk Bag Containers Discharged?

If you use bulk bag containers in your business, you may be wondering about the best way to get those bulk bag containers discharged. There are several methods for discharging bulk bags, each with their own advantages and disadvantages. Here’s a guide to discharging bulk bags for your operation.

What Is Discharging?

Before talking about how bulk bag containers are discharged, it’s important to understand what exactly discharging is.

Bulk bags are a tremendous boon to any operation involving the storing and transportation of dry goods. There are three stages of a bulk bag’s journey: the filling of the bag with goods, the transportation and the discharging, or emptying, of the bag at its final location.

The most conventional way to discharge bulk bags involves releasing its contents through a spout at the bottom of the bag. Because material tends to be packed very tightly in the bulk bag, some agitation may be required to get the product flowing out of the bag and into the container.

There Are a Number of Methods for Discharging Bulk Bags:

  • Gravity: The simplest method of discharging bulk bags is to let gravity do the work by lifting the bag up over the desired discharge area, opening the discharge spout and letting in flow. While this is a simple and inexpensive method, it’s difficult to control the flow of product from the bag.
  • Flexible Screw Conveyor: The flexible screw conveyor, or helix conveyor, is advantageous in that it’s a very versatile method of discharge that allows free-flowing and non-free-flowing materials without any separation of blended products.
  • Bottom Cut: If your bulk bag does not contain a discharge spout, as most do, the bag can be discharged using a C-shaped cut on the bottom to open the bag. This is an effective way to discharge your material if you don’t have a spout. However, you cannot stop the flow of product until the bag is nearly empty.
  • Full Dump: A full open dump is a method of discharge where the entire bottom of the bag is opened and all of the contents are dumped out at once. This is a simple and fast method of discharging your product, but you have no control at all over the flow of product — it all comes out immediately.

Types of Bulk Bags

There are a few types of bulk bags you can use. These include:

  • Duffel: A duffel-top bulk bag is one that has a duffel opening sewed to the top of the side panels, rather than a traditional top, which may make filling easier.
  • Flat: A flat-bottom bag is simply one where the base of the bulk bag is flat. They can come with a spout at the top, a duffel top or a full open top for filling.
  • Conical: Conical bulk bags, or full base discharge bags, are designed with a tapered base for faster and easier flow with product not getting stuck in corners.


Spout Discharging Tips:

Because product is often packed very tightly in bulk bags and needs to flow freely for optimum discharge, some form of agitation may often be called for. The right approach to agitation can be quite helpful in generating an effective discharge. There are two main types of agitation that have proven to be highly effective in this regard: spout agitation and side agitation.

  • Spout Agitation: In spout agitation, one applies an agitation force right at the discharge spout using paddles, pads and rods, or vibration. Agitating in this location tends to be effective because the bottom of the bag is where the material is usually the most compacted, due to the nature of filling and transportation. Spout agitation is most effective right as the bag is first discharging, when the bag is full and the head pressures from the material load are greatest.
  • Side Agitation: Side agitation is a method wherein the paddles, vibration or pads and rods are used to apply agitation force to the lower half of the sides of the bag. Side agitation can be very effective for a more complete discharge, forcing materials that may otherwise become trapped in the corners of the bag to make their way down the spout.

It’s important to use spout agitation or side agitation at the right time in the cycle. Fully agitating at the spout and side at the same time can result in greater compaction, while applying spout agitation first as the bag begins to discharge, followed by side agitation, is a good way to get a complete and fast discharge.

That being said, you may find that a different method — applying spout and side agitation perpendicular to each other alternatively at reduced force — may be most effective in some cases, effectively “massaging” the product through the spout. Your most effective method may vary depending on your type and amount of product, and your equipment.

However, you would never want to start with side agitation only as you begin the discharge, and then switch to spout agitation once some of the top material has worked its way down toward the middle of the bag, as this is likely to have the opposite of the desired effect.

Where to Find Quality Bulk Bags

Whatever your bulk bag needs are, contact Midwestern Bag & Supply to fill them. Midwestern Bag & Supply is a leading supplier of FIBC bags that manufactures its bags from virgin raw materials, customizable for your specific needs.

Whether your business requires FIBC bulk bags capable of holding between 500 and 4,000 pounds of product, GFSI-recognized food-grade bulk bags, bulk bags designed especially for food, chemical,  and agricultural products or some other type of bulk bag, Midwestern Bag & Supply can accommodate you.

Get in touch today for a free quote on strong, safe reliable bulk bags for your business.

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