what does "air gap" mean?

[miamicuse]

I saw this soap/lotion dispenser on Ebay:

What does it mean by "air-gap"?

MC

[trader4]

An air gap is a device that can go into a spare sink hole. It gets inserted between a dishwasher and the sink drain. It's purpose is to provide an overflow and air break so that if the sink drain backs up, water can;t syphon back into the dishwasher. Most homes don't use them, instead they just loop the dishwasher drain hose up high under the counter. Some places may require an air gap per code.

That soap dispenser is a soap dispenser plus air gap so that you can get both into a single sink hole. If you don't need the air gap, it will still function as a soap dispenser.

[miamicuse]

Thank you for the explanation.

MC

[Sacramento Dave]

the possibility of contaminated waste from being pulled back up into the potable water system. If a city water main breaks it can cause a vacuum on your water system. That's also why they put those irritating vacuum breakers on hose bibs. Most commercial kitchen all the sinks drain into floor sinks The drain pipe from the sink is cut a minimum of 1" ( 1"air-gap) above floor sink. Well probably more information than you needed. Now if you are thinking of leaving the air gab out of you dishwasher drain. Some areas you can do a loop with the waste hose some areas the air gap its code. I think the air gap is a good safety factor.

[Pop]

I'd use Ask the Seller a Question if I were you; syntax can get pretty badly mangled by auction sellers. He might or might not mean what it really means.

Pop