01Why gravity at all
No motor, no drive, no inverter, no controls. Product moves because the run falls, which makes gravity the cheapest conveyor to buy, effectively free to run and close to free to maintain. It suits packing stations, accumulation buffers, manual sort areas and the in-feeds and out-feeds either side of labelling, vision, strapping and wrapping machines. The trade you accept is line pressure: boxes touch and push on each other. Where that is not acceptable, you need powered.
02It has to fall, and the fall gets tested
A gravity run needs a gradient, typically 2 to 5 per cent, and where you land in that range depends on the product, its weight and the roller type. This is the number most worth getting right, because too little fall stalls product mid-run and too much delivers it faster than an operator can handle. We test on site or simulate the run to confirm the gradient rather than applying a default and hoping.
03Roller pitch and the three-roller rule
At least three rollers should be under the product at all times, which means the pitch comes from your shortest item rather than your average one. That is why the Mini Roller 100 Series exists: a tight enough pitch that short items stay supported instead of dropping into the gaps. Cartons, totes, trays and pallet bases with flat, rigid undersides all run well. Very soft or irregular bottoms are the exception and need either a tighter pitch or a short belt section to carry them across.
04Speedtrack, for layouts that are not straight lines
The Speedtrack modular system covers straight sections, bends, spiral bends, gates and merges, so a gravity line can follow the shape of the building rather than forcing the building to accommodate a straight run. Spiral bends are the useful one: they drop product through a level change in a small footprint, which is often the difference between gravity working in a space and not. Gates let people through the line without climbing over it, which sounds minor until you watch a picker do it forty times a shift.
05Load, frames and hygiene
Roller diameter, wall thickness and side frame are sized to your load and support span rather than picked from a standard build. Side frames come in aluminium, stainless steel and other materials, so a hygienic or food-grade area gets stainless frames, rollers, bearings and finishes specified for the standard required. Worth raising at enquiry, because the standard build is not stainless.
06Controlling product without powering the line
Brake rollers slow product at the discharge, side guides keep it tracking, and roller pitch itself changes how freely product runs. Between them you have more control than the absence of a motor suggests. What gravity cannot give you is exact spacing or timed release, so where the next machine needs product presented at a fixed interval, a short powered zone goes in at that point rather than powering the whole line.
07Mixing gravity and powered
Most real layouts are hybrids. Gravity handles the stretches where product only has to travel, and powered handles the parts that need control. The range integrates with 24V motorised roller, lineshaft conveyor, belt and modular belt conveyors. If you need zero-pressure accumulation, precise speed control, long horizontal runs where no slope is available, or heavy throughput with complex merges and diverts, powered is the right answer and zero line pressure conveying is where to start.
Where else to look
For small-product transfer lines with roller direction switchers for merging and branching, see very light duty conveyors. For a run that has to move around the building or fold away between jobs, flexible conveyors are the answer, and for loading containers and trailers use vehicle loading conveyors. Maintenance across the whole gravity range is periodic cleaning, a visual check of rollers and bearings, and confirming that gradients and stops are still set where they were commissioned. LVP Automation specify, supply and install these from Finglas, Dublin 11 as part of our wider automation services.