Commercial Dishwasher Case Study: 9,000 Meals a Day

A university campus ran one central canteen with four undercounter machines and eleven staff on wash-up. At each meal peak the backlog queued past the tray return, and clean stock ran out before the last sitting. Liangji supplied one commercial dishwasher running as a single pass-through line. Wash-up labour dropped to six people, and clean stock stopped being the limit on how many students the hall could serve.

Project Snapshot

The Problem: A Peak That Lasts Two and a Half Hours

Campus catering is a peak business. The kitchen may be open all day, but almost all of the work lands in two windows of about two and a half hours each. Everything about the wash-up has to be sized for that peak, not for the daily total.

The old arrangement used four undercounter machines placed close to the tray return. Each machine is capable on its own, but they shared a bottleneck: the operator loads a rack, closes the hood or door, waits, unloads, and starts again. Four machines meant four people standing still while the cycle ran.

Two consequences followed. Clean tableware ran out before the final sitting, so staff hand-washed bowls at a sink that was never meant for that volume. And water and chemical use scaled with the number of machines rather than with the number of items washed, because each unit heats its own tank and each door opening loses heat.

Why We Chose a Conveyor Line Over More Undercounter Units

Three options were on the table.

Add two more undercounter machines. Excluded. It repeats the same bottleneck six times, needs six sets of tanks and heating, and still depends on an operator standing at each machine. The peak problem stays unsolved.

A rack conveyor machine. Considered and then set aside. It is a real step up from undercounter units, but the campus layout puts the tray return and the clean shelf on opposite sides of a walkway, so racks would still be moved by hand between the two.

A tunnel conveyor line with heat recovery. Selected. Ware passes once, in one direction, on a single conveyor, so throughput is set by belt speed rather than by a person's pace. The heat recovery unit takes the energy out of the exhaust and the waste water and puts it back into the incoming rinse water, which matters in a kitchen that runs two hot peaks a day.

The Commercial Dishwasher We Built

The machine is a Long Dragon automatic conveyor unit built around the canteen's own tray and bowl sizes. That is the first thing we check in any project, because a line is only as fast as the widest item that has to travel through it.

The wash section runs over a dedicated tank, the rinse section uses water heated with recovered energy, and the drying section is sized so that ware leaves warm and dry enough to stack straight onto the clean shelf. Wash arms are removable without tools, which is what makes the daily end-of-shift clean practical for a crew that is already tired.

We build these units at our Zhangzhou Jiaomei base, a 10,000 m² production facility with ISO 9001 quality management and more than 100 patents across the range. The site was also looking at energy cost, so we proposed the heat recovery dishwasher variant that recovers rinse energy rather than dumping it.

Installation: How the Work Ran

Commissioning was planned around the canteen's opening hours, because a campus canteen cannot close for a week. Demolition, floor work and the new services ran during a term break, and the line was positioned, levelled and connected over five days.

The remaining days were spent setting the machine to the kitchen rather than the other way round. We set the belt speed against real trays, adjusted the rinse temperature and dwell, and then ran three full service simulations with the customer's own crockery.

Because this is a single-pass machine, the work is a sequence rather than a job. One person loads at the entry and one takes clean ware off at the exit.

Testing and Quality Control

On site we measured wash and rinse temperatures at the tank and at the ware surface, checked the final rinse pressure, and confirmed the drying result on the trays that stack deepest, because those are the items that leave wet.

Then we ran three consecutive peak simulations with a full load of used ware. Clean ware from each run was inspected for food residue and water marks, and the count of clean items per hour was recorded against the machine's rating. The venue's own hygiene checks were repeated on the same day, so the operator could compare the new line with the old method on its own paperwork.

Results: What the Numbers Show

One line now washes the tableware for 9,000 meals a day. The wash-up crew is six people instead of eleven, and clean stock no longer runs out during the last sitting, which was the original complaint.

Water consumption fell by roughly 40 per cent, because four separate tanks were replaced by one line that reuses rinse water through the heat recovery circuit. Electricity per item also dropped, since much of the rinse heat now comes back from the machine rather than from the boiler. The operator has since added a second service window in the same hall.

What This Case Means for Your Project

Peak volume, not daily volume, sizes a commercial dishwasher. Measure your busiest 30 minutes, count the pieces that must pass through in that window, and let the machine take the operator's pace out of the equation.

We build conveyor, pass-through, undercounter and heat recovery machines for canteens, hotels, hospitals and central kitchens, and we build them around your trays. Send us your peak counts and a drawing of the wash-up area, and see how our commercial conveyor dishwasher system was configured elsewhere, or contact the factory for a layout and a quotation.