Knowing which kind of elevator system you are working with is important, because this determines which kind of product the elevator will be most effective in moving. Today we’re looking at two common, slow speed bucket elevator designs: Continuous Discharge and Positive Discharge. Each system has its place in the industry, but you can only operate efficiently and effectively if you fit the right system to the right job. Let’s take a look.
Continuous discharge elevator systems operate at a range of speeds between 1 and 250 feet per minute and rely on gravity to discharge materials from their buckets. Buckets are designed to tilt as they top the head pulley to the down leg which allows the carried material to pour from the bucket at a natural rate. Generally, continuous discharge buckets utilize the design features of the bucket to guide material into the outlet. This is unlike Positive Discharge systems, in which the buckets use mechanical trippers to cause their payload to be dumped.
Continuous discharge bucket elevator systems are preferred for handling materials that are more inconsistent and need “gentler” handling, both to protect the material and to protect the buckets themselves from wear and tear. The discharge method is ideal for:
- Inconsistently sized or light materials
- Friable materials
Positive discharge elevator systems are also gravity in nature but use mechanical trippers to dispense materials. This is the primary difference from continuous discharge systems. The force needed is produced not by high speeds, but by a quick mechanical “flip” at the head that jolts the contents into discharge down the chute or onto a conveyor belt. Positive discharge systems move at very slow speeds, which make them ideal for use in food and pharmaceutical manufacturing. They can be used to compartmentalize finished foods into package sized lots for the packing process. This design is also suited for materials which may take extra time to discharge or are difficult to dislodge, such as:
- Sticky materials
- Fragile materials
- Aerated or “powdery” materials
Positive discharge systems also reduce loss in efficiency via back legging or down legging by holding buckets parallel to the floor and stable before being flipped.
Maxi-Lift has been leading the material conveyance industry with top-of-the-line elevator buckets and bucket elevator accessories and support for over 50 years. Contact our sales team for assistance, guidance and service that will get you up and running – the right way – fast!