Eco-friendly dishwasher uses superheated steam instead of soap to clean dishes

New dishwasher technology could soon save you money on water, electricity and detergent, a study reveals.

Researchers performed simulations of a dishwasher system that uses superheated steam instead of soap to clean dishes.

Superheated steam is extremely high temperature steam generated by heating saturated steam obtained from boiling water.

Results of computer simulations suggest that such a dishwasher would be able to kill 99% of bacteria on a plate in just 25 seconds.

For now, the dishwasher only exists as a computer model, not a physical object, but the researchers say their study provides a foundation for the development of next-generation dishwashers.” .

The dishwasher, which has not yet been built, looks like a box with solid side walls, an upper opening and a nozzle at the bottom

The dishwasher, which has not yet been built, looks like a box with solid side walls, an upper opening and a nozzle at the bottom

SUPERHEATED STEAM

Superheated steam is extremely high temperature steam generated by heating saturated steam obtained from boiling water.

Superheated steam is obtained by adding heat to saturated steam, which raises the temperature above the saturation temperature at constant pressure.

The use of superheated steam allows more efficient operation of devices that convert heat into mechanical work.

It is also used in food processing for cooking and drying, and for cleaning surfaces such as hard and tiled floors, industrial processing equipment and furniture.

Source: Germann et al/Encyclopaedia Britannica

The study was conducted by researchers from the Technical University of Dortmund and the Technical University of Munich, Germany.

“The use of superheated steam in dishwashers as a means of reducing water consumption and cleaning time without the use of chemical cleaning agents has great future potential for restaurants, hotels and hospitals,” they state in their paper published in Physics of Fluids. .

“In these sectors in particular, hygienic safety is an important concern in addition to the disposal of food residues.”

Conventional dishwashers often do not kill all harmful microorganisms left on plates, bowls and cutlery.

They also require long cycle times that use large amounts of electricity, and the soap pumped in and out is released into water sources, polluting the environment.

Superheated steam dishwashers could be a more efficient and environmentally friendly solution, the researchers say.

Their proposed superheated steam dishwasher would initially cost more, but would pay off in the long run with savings in water, electricity and detergent.

It would be ideal for use in restaurants, hotels and hospitals, which must meet high hygiene standards.

Concentration of bacteria on the plate inside the dishwasher over time.  Superheated steam kills bacteria in 25 seconds

Concentration of bacteria on the plate inside the dishwasher over time. Superheated steam kills bacteria in 25 seconds

For their study, the team modeled the flow pattern and shape of the high-temperature steam jet in the proposed machine.

The team says the next-generation dishwasher would essentially be a box with solid sidewalls, a top opening, and a nozzle at the bottom.

A plate covered in bacteria would be placed directly above the nozzle, and once the plate reaches a threshold temperature, the microorganisms are inactivated.

“Steam comes out of the nozzle at a very high speed,” said study author Natalie Germann from the Technical University of Dortmund.

As the steam expands in the dishwasher, shock waves and eddies develop near the nozzle outlet, around the perimeter of the plate, and on the side walls of the dishwasher.

“These waves and vortices allow a long interaction time with the superheated steam to release its latent heat and increase the temperature promoting bacterial deactivation,” explain the authors.

Current dishwashers in homes and businesses circulate soap and water to clean dishes (file photo)

Current dishwashers in homes and businesses circulate soap and water to clean dishes (file photo)

While the team focused on bacteria, the steam jets could also be used to inactivate other microorganisms, as well as remove food debris.

The researchers admit that it takes 25 seconds to wash a single plate, so real-world applications – like in a restaurant – would require a system that washes multiple plates at once.

“In the future, we will simulate a full-size dishwasher with multiple plates and we can give more quantitative results,” Germann said.

“We will have to check how fast the steam can reach all places in the dishwasher.”

A ROBOTIC DISHWASHER CAPABLE OF WASHING HUNDREDS OF PLATES COULD REPLACE HUMANS IN RESTAURANT KITCHENS

A robotic dishwasher capable of washing hundreds of dirty plates could replace human workers.

Dishcraft, a cleaning service in San Carlos, Calif., developed the system in an effort to spare humans grueling shifts in restaurant kitchens.

Dishcraft’s robot currently only works with plates and bowls the company develops itself, with metal parts attached to the bottom.

Workers place a stack of plates in a slot, where the robot scoops them up each before hanging them over a food scraper that removes leftovers before rinsing off the rest of the dirt using recycled water .

The robot uses cameras and sensors to detect when the plate has been cleared.

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