Inquiry (采购产品): Valve Hi, I am looking for a valve I can splice into a 1 1/2" PVC plumbing drain line to prevent backflow from the washer into the kitchen sink. Is there such a valve that doesn't require pressure (other than water drain flow) to function? Thank you very much for your help. **** Hidden Message ***** Joe Eckhaus 20905 Company: Consumer E-mail: jeckhaus@verizon.net **** Hidden Message ***** jeckhaus@verizon.net