Disclosed herein is a plumbing spout that has back flow protection. The spout positions a check valve vacuum breaker underneath the pull up knob in a plug assembly. The spout provides back flow protection even though it has no fluid control valve for controlling flow through to the spout outlet....http://www.google.sh/patents/US6317905?utm_source=gb-gplus-sharePatent US6317905 - Spout with vacuum breaker protection
