Crate Washers and Washing Lines

Pohjaranta crate washers are flow-through washing lines: crates, trays and other items travel on a conveyor through prewashing, washing, rinsing and drying in a continuous flow. They are sometimes called tunnel washers, but unlike laundry tunnel washers they clean hard, reusable items. We design and build every crate washer and washing line at our own factory in Säkylä, Finland, sized to your capacity and hygiene requirements.

What our washing lines clean

Most of our lines clean returnable transport packaging for the food, beverage and logistics industries. In delivered projects the lines have washed plastic transport crates, beverage trays, steel bins, pallet boxes and pallets, food industry moulds and plates, footwear, tyres and deep-drawn metal parts.

The same technology works as a tray washer for beverage trays and as a crate washer for crates of different sizes. Wash programmes, nozzle angles and drying are matched to the item and the soil, and options such as label removal can be added.

Single-row or two-row crate washing line

In a single-row crate washing line the crates pass through the machine in one lane, and a narrow tunnel model is available for tight spaces. A two-row line washes two lanes side by side and doubles the capacity, so it is chosen for high production rates such as breweries and dairies.

The largest deliveries use two parallel washing modules: a beverage tray washing line washes 2,500 trays per hour, and a crate and pallet washing line for the cheese industry handles 1,000 crates and 100 pallets per hour. The High Capacity Crate Washing Line is rated at 2,000 crates per hour.

Washing line stages

Prewash removes loose soil and food residue before the main wash. Because the coarse soil stays in the prewash tank, the wash solution stays cleaner and less detergent is used.

Wash uses a heated wash solution with dosed detergent. The temperature is set per programme, and in units with a drum screen solids are separated from the wash water continuously.

Rinse removes detergent residue with clean water. Final rinse water can be recirculated to the pre-rinse, which saves both water and energy.

Disinfection is added as a separate stage when your hygiene requirements call for it.

Drying blows the water off so the crates return to production dry. In delivered lines the residual water has been 6–12 grams per crate, and below 2 grams at best.

Built from modular units

Each line is assembled from standard units, so it contains exactly the stages your items need: single-row and two-row prewash, wash and rinse units, drum screen units, a wash unit with oil separator for greasy and oily parts, a pump station that recirculates drying water, and single-row and two-row dryers. The washing units are listed on this page and the dryers on the Crate and Tray Dryers page.

Where needed, the line is connected to destackers, stackers, conveyors and palletizing robots, so one delivery covers receiving the dirty crates, washing, drying and stacking or storing the clean ones.

Sizing, manufacturing and commissioning

Capacity is sized to your peak production rate, not to the average. Mechanical, electrical and automation design are done in-house, the wash sections are made of stainless steel, and the line is test run at our factory before delivery and again with your own crates before handover. Installation is timed to a production shutdown.

Pohjaranta has designed and manufactured equipment in Säkylä since 1992, and our washing lines have been delivered to Finland, Estonia and Norway.