Home Appliance

There is an infinite variety of dishwashing machine that cater to the foodservice operator’s special problems of dish volume, labor shortage and lack of space. The major machines will be described briefly. Most machines are designed around the 20-inch dish rack, 22-inch hospital tray and 28-inch banquet tray.

Single Tank Stationary Rack Door Type ( dishwashing machine )

Stationary Rack Door - Dishwashing Machine

Single tank, stationary rack door type machine consists of a tank of wash water and detergent at a set temperature which is circulated by an electric motor-drive pump through spray nozzles above and below a rack of dishwashing machine. It may have a hood, cover or door through which the rack of dishes is inserted. Final rinsing is done by fresh hot water introduced by a separate set of pipes or nozzles. If set in a counter, it may be known as a “counter-type machine”. If rinse water uses the same nozzles as the wash water and both wash water and rinse water are dumped after each cycle “single temperature” may be added to the above title. If chemical sanitizer in the water is used in place of 180F water for rinsing, the machine title includes “chemical sanitizing” machines. Doors may be on one or more sides.

Conveyor-Rack Dish Machine ( dishwashing machine )

Conveyor rack dish machine in its simplest form, the single-tank, contains one tank of hot wash water with detergent spray on the dishes top and bottom, driven by a power pump. A final rinse of fresh 180F-plus water from the hot water line is used to remove wash water and sanitize. A new feature is a conveyor that carries the dishes over the
sprays and through the machine at a timed rate of speed. A variation of this is the two-tank machine where the final rinse is preceded by a pumped rinse through nozzles above and below the rack after it his passed over the wash-water tank. The second tank holds the rinse water at a thermostatically controlled temperature. This is followed by the usual final rinse.

Rack Conveyor Dishwasher - Dishwashing Machine

To obviate the need for extensive prescraping of the soiled dishes, some dishwashing machine have a third tank with water
below 120F for prerinsing the gross soil from the dishes before they go over the washwater tank. The addition of each tank adds to the length of the machine. Also, there should be table space at the entrance to the dishwashing machine to line up two or three racks of dishes (approximately 40% of the table space) and space for three to five racks of dishes (approximately 60% of the table space) at the exit end of the dishwashing machine to permit the dishes to air dry before stacking in carriers. Usually some type of conveyor is desirable for returning the racks from the clean end to the soiled dish end of the dishwashing machine to eliminate excessive walking.

There are two common variations of the rack machine. One permits the loading of the rack into the side of the loading end of the machine rather than through the end. After washing and rinsing the dishwashing machine discharges
the racks through the same side at the exit end of the dishwashing machine. This permits placing the machine across the narrow end of a small room and having the soiled dish table and clean dish table come down the sides with the operators in the center aisle.

The other type of rack machine is the carousel dishwashing machine where the exterior part of the rack conveyor forms a
continuous loop from exit to entrance end of the dishwashing machine. It may form two semi-circles in and out of the machine and then run parallel to the machine, but it is not limited to that configuration. Some machines have the racks fixed to the conveyor; others have the racks removable. While it is not desirable to have one person handle both soiled and clean ware ‘this machine allows one person to both load and unload the machine during stack times if he washes his hands between handling the soiled and the clean dishes. While it is expensive, the carousel machine obviates the need for a rack return conveyor from the clean to the soiled end of the dishwashing machine. Freshwater and Steckler rate carousel type dishwashing machine into three types based on rack capacity per hour-Type 1, 180 racks; Type 11, 387; and Type 111. 480 racks per hour.

Flight Dishwasher ( dishwashing machine )

Flight Dishwasher - Dishwashing Machine

The flight dishwashing machine operates on the same principle as the conveyor rack machine except that the dishes and trays are hand-placed between rows of plastic-tipped pegs to make up a continuous conveyor that travels around through the machine in a vertical plane. The width of the conveyor and the distance between the crosswise rows of pegs varies between makes and models of machines. Racks of glasses, cups and silverware are placed on top of the pegs. These machines are necessarily long to allow sufficient space to hand load them and to permit the ware to dry after rinsing before removal.

There are other types of dishwashing machine. Some are modifications of those described. Some tank types wash the dishes either by forceful movement of water or application of ultrasonics while the dishes are immersed in the water. Then there are various types of glass-washers and silverware washers. The most prevalent are flatware washers that tumble the ware as it washes. Some also perform a sorting function. Silverplate is burnished by tumbling it in a rotating cylinder of small steel balls.

Reference : Dishwashing Machine