Two conveyors can both be described as stainless steel and IP66, and only one of them can be cleaned in twenty minutes without a tool. The difference is in the details that do not appear on a datasheet.

IP rating: what it does and does not tell you

IP66 means dust-tight and protected against powerful water jets. It says nothing about whether the water that hits the conveyor can drain away, whether the frame has crevices, or whether the belt can be lifted for cleaning.

For washdown areas, specify IP66 as the minimum for motors and sensors, IP69K where high-pressure, high-temperature cleaning is used, and stainless enclosures with sloped tops so water does not pool. Then stop relying on the rating and design the drainage.

Drainage and slope

Water has to leave the frame. A square tube with welded ends holds water until it rusts from the inside, and a pool of standing water under a belt is a microbiological risk that no cleaning programme will fix.

Use open profiles, or square tube with drain holes at the lowest point of every section and at every low point created by a support. Slope the frame 0.5 to 1 degree towards the drain. Fit a removable drip tray under the belt return and slope that too.

Check the floor drain position before designing the frame. A conveyor that drains onto the floor on the far side of the room is a slip hazard and an audit finding.

Frame and fasteners

  • 304 stainless for dry and low-chloride environments, 316 for salty, acidic or high-chloride cleaning chemicals.
  • Continuous welds, ground flush, on all food-contact surfaces. Stitch welds trap product.
  • No exposed threads, no hex sockets facing upwards, no rivets.
  • Sanitary fasteners or captive bolts; a dropped nut in a food line is a recall risk.
  • Rounded corners and a minimum radius of 6 mm on all product-contact edges.

Belting and belt support

Choose a belt that is approved for direct food contact and for the cleaning chemicals in use. A belt that is fine with alkaline foam may degrade with chlorine, and the failure appears as surface cracking after three months.

Support the belt on a low-friction slider bed with drainage slots, not a solid plate. A solid plate holds water and product debris against the underside of the belt. Where the product is wet, consider a mesh belt over a spray bar, which cleans itself.

Field noteA ready-meal plant replaced a stainless conveyor because of Listeria found in a frame crevice. The replacement had the same square tube and the same welded end caps. The organism returned within a year. The problem was the profile, not the material.

Motors, gearboxes and sensors

Mount drives above the frame, not below it, where drips and cleaning water collect. Use a washdown-duty gearbox with a breather that does not ingest water during cooling, or a sealed drum motor inside the head pulley.

Sensors should be stainless or fully encapsulated, with cables routed in open trays that drain, not in conduit that fills. A cable entry that points upwards is a water trap.

Access for cleaning

Every surface that a cleaning brush can reach will be cleaned; every surface it cannot reach will be visited by an auditor. Design for access:

  1. The belt can be lifted or removed without tools.
  2. The frame ends are open, so a hose can be passed through.
  3. Guards are hinged or quick-release, and stored on the machine, not in a cupboard.
  4. There is 300 mm of clearance between the conveyor and the wall for cleaning.

Validation

After installation, clean the conveyor to the written procedure and swab the frame, the belt underside and the drip tray. If the swab results are acceptable, write the procedure down with the actual times and chemical concentrations. The next auditor will ask for exactly that document.