Before we bought our house, the washer and dryer were relocated and put on a drain line shared by the kitchen sink, Anytime that the washer drains it backs up into the sink. This is my wife's #1 "Honey do". does anyone know of a one way valve that could be put between the sink and the joint so that everything goes into the drain and not into the sink? I know that I could install a shut off valve but my wife is not going to turn that valve before and after each load of wash.

Thanks in advance,

e.j.