Accumulation conveyor plays a critical role in warehouse automation systems in that it allows for the buffering and accumulation of product in preparation for downstream processes that may operate at a different speed than upstream functions.
Accumulation conveyor can be used to transport and regulate product flow to various warehouse processes including: order picking, packing, sortation, palletizing and truck loading, and wrapping, taping, and strapping of goods in preparation for shipping.
Types of Accumulation Conveyor
Accumulation conveyor works by temporarily buffering, or holding, product on a conveyor until the conveyor control system tells it to release product. This is accomplished by either having items coast to a stop by gently resting against the items in front of them, or by having items come to a stop without allowing any contact between them. The differences between these methods translate to the two categories of accumulation conveyor systems available today.
Accumulation Conveyor Categories
CONTACT ZERO-PRESSURE ACCUMULATION CONVEYOR allows products to gently rest against each other, minimizing the weight pushing against each item. This pressure is limited to one or two accumulation zones and consists of a gentle bumping as product comes to a rest.
Zones for a contact accumulation conveyor generally range between two and six feet in length, depending on the conveyor speed and the size and weight of the parcel being handled. Most often photo-eyes are used to sense that the product is in position and trigger the accumulation or discharge of product along the conveyor as needed. (See an example of this conveyor in the left two lanes of conveyor in the video above.)
NON-CONTACT ZERO-PRESSURE ACCUMULATION CONVEYOR accumulates product without allowing any contact between items. This is accomplished by dividing the accumulation conveyor into individual zones that each hold one item. (e.g. A 30″ zone might be used to hold a 24″ carton, allowing 6″ gap between cartons.)
A photo-eye is often used to determine the presence of an item within each zone and subsequently allow or disallow the movement of product along the conveyor. Zone lengths can be built from 18” to as much as 6 feet long.
Zero pressure accumulation conveyor buffers products without any buildup of line pressure between items or at the discharge end and works especially well with fragile products or products of varying weights and sizes. (See an example of this conveyor in the right lane of conveyor in the video above.)
Accumulation Conveyor Release Modes
- Singulation mode discharges each accumulation zone in sequence (i.e. one item at a time). It can be compared to cars moving away from a stoplight. The first one moves, then the next, and so on.
- Slug mode discharges all the zones at one time in a continuous stream of product. This mode allows higher throughput at lower conveyor speeds.
24 Volt Accumulation Conveyor
For throughput rates below 1,800 per hour on a single line, 24 Volt DC accumulation conveyor (also know as MDR conveyor) is Invata’s recommended choice for accumulation conveyor.
Available in roller or belt versions, 24 Volt DC conveyor is ideal for transporting and accumulating a variety of products for the following reasons:
- Safe for operators: Low torque rollers can be easily stopped with one hand.
- Inexpensive to install: Plug-and-play components don’t require wiring to centralized control panels savings substantially on electromechanical installation costs.
- Inexpensive to operate: Run on demand technology uses a fraction of the power used by conventional accumulation conveyors, while diminishing both wear and noise levels.
- Inexpensive to maintain: Cheaper to maintain than conventional conveyors like belt-driven live roller conveyor and line shaft conveyor.
- Controllable from a centralized point: Ethernet connectivity enables centralized control of all speed, direction, and operation, if desired.
- Easily reconfigured: Variable speed controls enable reconfiguration as requirements change with no need for expensive rewiring or replacing of motors, just simple programming changes.
- Long Life: Typical 24 Volt motor life is up to 20,000 hours, averaging over 8 to 10 years of use.