Commercial Dishwasher Case Study: A Hospital at 82 °C

A hospital central kitchen washes for 4,500 patients, staff and visitors a day, and its hygiene audit does not accept a warm rinse. The kitchen was running four undercounter machines and a manual sink line, with water consumption, labour and rinse temperature all drifting at peak. We installed a long dragon line with heat recovery and a monitored final rinse. Throughput rose, water use fell, and the audit record is now printed from the machine.

Project Snapshot

The Problem: A Peak That Lasts Three Hours

Hospital catering is not a restaurant shift. Lunch arrives as a wall: 14,000 items in under three hours, from ward trolleys, staff canteen and visitor service. Undercounter machines cannot stack that work, so the kitchen held crockery in sinks and ran a manual pre-wash line on top.

Hygiene was the harder problem. A final rinse that starts hot and cools under load is difficult to prove afterwards, and the audit wants a record rather than an assurance. The kitchen also had to keep a pot-wash station and a separate tray route, because ward trays cannot share a wash with catering crockery.

Two site limits fixed the layout: a fixed fresh water supply, a steam line already serving the cooking suite, and a wash-up room that is a corridor of about 11 m rather than a hall.

Why We Chose a Long Dragon Line Over Undercounter Units, a Pass-Through Machine and a Batch Box Washer

A fifth undercounter machine. Excluded. It adds capacity in the wrong place, because the bottleneck is the drying bench, not the wash cycle.

Pass-through machines in a bank. Excluded. Each unit still needs its own rinse and operator, so water and labour scale with volume, not load.

A batch box washer. Excluded. Excellent for trays, pots and mixing bowls, and far too slow for 14,000 items arriving inside three hours.

A long dragon conveyor line with heat recovery. Selected. Racks enter at one end and exit dry at the other, rinse temperature is held on the machine, and the heat recovery unit takes warmth out of the exhaust before it leaves the room.

The Machine We Supplied

The line runs a pre-wash, a main wash at 55 to 60 °C and a final rinse held between 82 and 85 °C, with the tank temperature logged rather than only displayed. Throughput is set at 4,500 items per hour, which matches the client's published capacity band and leaves headroom over the 18,000-item peak day.

The heat recovery unit sits on the exhaust and pre-heats the incoming rinse water, which is where most of the fresh water saving comes from. The line is electrically driven for the conveyor and rinse booster, with the steam connection used to hold tank temperature at low cost.

Liangji machines are built at the Jiaomei production base in Zhangzhou, and the same platform is offered in shorter body lengths, so the 11 m room did not need structural work. The long dragon automatic dishwasher is the model installed here, and our heat recovery models cover the same duty in a shorter footprint.

Installation: How the Work Ran

The kitchen could not close, so the work ran over nine days with the old machines kept alive to the last one.

Days one and two were plant and drainage: the conveyor dropped into the existing floor channel, and the rinse booster was connected to the steam line already in the room. The heat recovery unit went on the exhaust duct above the line, keeping the floor clear.

Days three to five were commissioning. Racks were run empty to set conveyor speed and rinse temperature, then loaded with the kitchen's own crockery mix, including heavy stoneware that behaves differently from light items.

The last four days were operator training on rack loading, on the pre-wash station and on reading the temperature log. Loading is where a conveyor line is won or lost: an overloaded rack comes out wet and gets washed twice.

Testing and Quality Control

Each machine is assembled and run at the plant before shipment, and the rinse temperature, tank temperature and conveyor drive are recorded on the test sheet that travels with the unit.

On site, the rinse temperature was verified with a calibrated probe at the final rinse nozzle on three separate days, at start-up, mid-shift and at peak. The kitchen's hygiene team also ran swab checks on crockery straight off the line.

Results: What the Numbers Show

Lunch peak now clears without a backlog in the sinks, and the manual pre-wash line is now kept only for pots.

Fresh water use fell by roughly a third against the four-machine routine, most of it from the heat recovery unit and from not refilling four tanks a day. Chemical cost per item also fell, because dosing is set against two tanks rather than four. The final rinse now holds at 82 °C or above all the way through service, and the audit is answered with a printed log.

The engineering team has since specified the same platform for a second kitchen block and used the hotel and canteen conveyor installations as a reference layout for its own consultants.

What This Case Means for Your Project

Warewashing capacity is not a machine count. It is a decision about where the bottleneck sits: wash, dry, or the bench where someone stacks racks.

If your kitchen peaks hard, sends mixed crockery and trays, or has to prove rinse temperature after service, send us the item mix, the peak hour and the room dimensions. We will propose a line length, a tank configuration and a heat recovery option, state the water and steam demand in writing, and quote the installation with the commissioning days included. Talk to our engineering team about your kitchen or start from the automatic commercial dishwasher range.