Backflow prevention device and relief valve control

• US 3,276,465 A
• Filed: 01/18/1963
• Issued: 10/04/1966
• Est. Priority Date: 01/18/1963
• Status: Expired due to Term

• Current Assignee: Fred K. Wyckoff
• Original Assignee: Fred K. Wyckoff
• Inventors: Wyckoff, Fred K.
• Application Number:
  US04/252,488
• Time in Patent Office: 1,355 Days
• US Class Current: 137/107
• CPC Class Codes: E03C 1/106 using two or more check valves
• CPC Class Codes: E03C 1/108 having an aerating valve
• CPC Class Codes: Y10T 137/2557 Waste responsive to flow stoppage
• CPC Class Codes: Y10T 137/262 Increasing pressure progressively closes then reopens by-pass or relief valve
• CPC Class Codes: Y10T 137/3149 Back flow prevention by vacuum breaking [e.g., anti-siphon devices]
• CPC Class Codes: Y10T 137/7848 Permits flow at valve interface

Claims

1. A BACKFLOW PREVENTION UNIT ADAPTED TO BE CONNECTED BETWEEN A SUPPLY MAIN AND A SERVICE PIPE, COMPRISING:

A FIRST CHECK VALVE AND A SECOND CHECK VALVE, SAID CHECK VALVES BEING CONNECTED IN SERIES, SAID FIRST CHECK VALVE HAVING AN INLET ADAPTED TO BE SUBJECTED TO THE PRESSURE IN SAID SUPPLY MAIN, AND SAID SECOND CHECK VALVE HAVING AN OUTPUT ADAPTED TO BE SUBJECTED TO THE PRESSURE IN SAID SERVICE PIPE;

A DIFFERENTIAL PRESSURE RESPONSIVE RELIEF VALVE COMMUNICATING WITH SAID CHECK VALVES AT A ZONE INCLUDING THE OUTLET OF THE FIRST CHECK VALVE AND THE INLET OF THE SECOND CHECK VALVE FOR EFFECTING DRAINING OF SAID ZONE;

AND MEANS CONTROLLING SAID RELIEF VALVE IN ACCORDANCE WITH THE DIFFERENTIAL PRESSURE ARCOSS