The bubble dishwasher uses rising air bubbles to move
water and abrasive
coffee grounds, to clean dishes.
As with all of my dishwasher ideas, this one is not meant to
save water. I have no shortage of water. It is meant to save on electricity.
One of the simplest ways to get water to circulate within a vessel, is to use fish tank air bubblers. As the bubbles rise, they drag water from the bottom of the tank, toward the surface. If the water contains soap and something abrasive, they will be moved about the tank as well. Coffee grounds are only slightly heavier than water. There are some plastic abrasive pads which are almost the same density as water. These could be chopped into small pieces, and allowed to circulate with the water. This would tend to abrade soft material from the dishes.
I could see doing this in a large Rubbermaid type container. A diffuser could allow bubbles to escape around the perimeter and center of the tub, at the bottom. Water with a suitable amount of soap and abrasive material will be placed in the tub. Then the bubbler is turned on for an hour or so. Most dishwashers run for about an hour. They consume a lot of electricity. A 12 volt fish tank bubbler, uses very little electricity.
A 20 watt unit moves 45 liters of air per minute. That's 2700 liters per hour. That's a lot of bubbles. It consumes 20 watt hours of electricity in an hour . This means that it could be run for 50 hours on one kilowatt hour of electricity. In my area that amounts to roughly one tenth of a cent per wash cycle, in electrical usage.
I am ordering a small air pump, to test this idea. Two batches of equally dirty dishes will be washed. The water temperature and quantity of soap for each batch will be equal. One batch of dishes will be placed in the water for 1 hour, with no attempt to circulate that water. The second batch will be subjected to one hour of bubbles.
That's about it. I will post photos and results soon.
Let me know if you think of anything that could improve the bubble dishwasher.