Rejuva

Industrial warehouse racking

Gravity flow racking

In a gravity flow rack the goods do not wait in a fixed location. They are loaded at the high end of an inclined lane and travel under their own weight to the picking face at the other end, which removes the intermediate aisles a conventional layout needs and, more usefully, turns first in first out from an instruction into something the structure enforces on its own.

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Gravity flow racking with pallets on inclined roller lanes

How a gravity flow lane works

A flow lane is a steel structure fitted with rollers or wheels set at a shallow incline, running from the loading face down to the picking face. A load placed at the top travels the length of the lane without any drive, any power supply or any intervention from an operator, and stops against the load ahead of it.

The speed is controlled rather than left to the slope, usually with brake rollers or separators that hold each load back so that the one at the picking face can be taken without the weight of the whole lane behind it. That control is what makes the system safe with full pallets as well as with cartons, and it is the part of the specification that follows the weight and the depth of the lane rather than a catalogue.

Because loading and picking happen at opposite ends, the two flows never cross. A replenishment truck working the back of the block does not meet a picker working the front, which is a safety argument as much as a throughput one.

Pallet flow and carton flow

The same principle at two scales, and the choice between them follows the unit you actually move rather than the size of the building.

  • Pallet flow

    Full pallets on roller lanes, loaded by forklift at the back and taken from the front. Used where a line of stock moves in whole pallets and the depth of the block is worth more than access to every pallet.

  • Carton flow

    Cartons and totes on wheel beds, usually at pick height with pallet racking above. Used in order picking, where the point is that the next carton presents itself at the face without anyone walking for it.

  • Combined installations

    Carton flow at the picking levels and pallet racking or pallet flow above it, in one structure. This is the common shape in distribution, because the two jobs happen at different heights in the same aisle.

Where gravity flow earns its cost

Gravity flow is a dense system, so it repays where the same reference moves in quantity and where rotation matters. Food, drink, pharmaceutical and any stock with a date on it are the obvious cases, because FIFO stops being a procedure that a picker can shortcut on a busy afternoon.

It repays less where the range is wide and the depth per reference is one or two pallets. A lane holds a single reference along its length, so a catalogue of many slow lines fills the block with part-empty lanes and loses the density that justified it. That is a layout question rather than a product question, and it is what the survey is for.

How we specify and install it

Rejuva delivers the project from the survey to the handover, and the specification follows the building and the movement rather than a standard configuration.

  1. Survey

    Measurement of the building, the floor and the access, and a reading of what moves: references, unit loads, depth per line and the picking rhythm the lanes have to keep up with.

  2. Layout

    Lane depth, incline, braking and the split between pallet flow and carton flow, set against the loads that will actually run and priced so the options can be compared.

  3. Installation

    Assembly to the agreed drawings, with the lanes set and tested loaded rather than empty, because an incline that works without weight on it proves nothing.

  4. Handover

    Load notices, the loading and picking sequence written down, and the inspection regime the installation falls under from its first day.

Frequently asked questions

How deep can a flow lane be?

Depth follows the load, the incline and the braking rather than a fixed limit, and it is set at the survey. What decides it in practice is how many pallets of one reference you hold at a time: a lane deeper than the line it serves stands part empty and costs density instead of adding it.

Does gravity flow need power?

No. The load travels on its own weight, and the brake rollers that control the speed are mechanical. That is one of the reasons the system suits chilled and frozen rooms, where powered equipment is harder to maintain.

Can it be installed in an existing warehouse?

Usually, and it is often the reason to consider it, since the density gained can postpone a move. What has to be checked first is the floor and the clear height, which is part of the survey rather than something to assume.

How does this differ from drive-in racking?

Drive-in is also a dense block, but the truck enters the lane and the last pallet in is the first out, so rotation is LIFO. Gravity flow is loaded and picked from opposite ends, so rotation is FIFO and no truck ever enters the structure.

Racking is not only bought. It has to be installed to the design, inspected while it is in use, repaired when it is hit, and moved or sold when the operation changes.

Every system sits somewhere on one trade-off: selectivity, meaning you can reach any pallet at any time, against density, meaning how many pallets fit into the same floor area.

Have a project in mind?

Describe what needs to happen in the building and we will come back with a proposed approach, the specialist who would carry it out and a budget you can work with.

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