Tri valve backflow preventer

• US 7,121,293 B2
• Filed: 03/22/2004
• Issued: 10/17/2006
• Est. Priority Date: 03/22/2004
• Status: Expired due to Fees

• Current Assignee: Gail Patricia Walter, Guy Robert Walter
• Original Assignee: Gail Patricia Walter, Guy Robert Walter
• Inventors: Walter, Guy Robert, Walter, Gail Patricia
• Primary Examiner(s): Hepperle, Stephen M.
• Application Number:
  US10/805,646
• Publication Number:
  US 20050205139A1
• Time in Patent Office: 939 Days
• Field of Search: 137/599.09, 137/599.11, 137/599.13, 137/599.14, 137/599.15, 137/601.2, 137/15.01
• US Class Current: 137/15.01
• CPC Class Codes: E03B 7/077 Arrangement of backflow preventing devices
• CPC Class Codes: F16K 27/006 of hydrants
• CPC Class Codes: Y10T 137/0402 Cleaning, repairing, or assembling
• CPC Class Codes: Y10T 137/87338 Flow passage with bypass
• CPC Class Codes: Y10T 137/87555 Having direct response valve [e.g., check valve, etc.]

Abstract

A tri valve backflow preventer having parts and materials preferably consisting of steel nuts and bolts, ductile iron operating nuts, nitrile rubber O-rings, nitrile rubber gaskets, manganese bronze valve adjusting stems, valve wedge gates made of ductile iron encapsulated with EPDM rubber, and ductile iron valve bodies. Material and parts are constructed in accordance with ASTM standards and the requirements of the AWWAC-509 and AWWAC-504 for gate valves and butterfly valves. The tri valve backflow preventer is used with a temporary conventional backflow assembly between existing water main pipe and new/upgraded sections of water main pipe while they are under construction. It is left in place when the temporary backflow assembly is removed. Its use saves extra inspection hours, extra man hours, extra equipment hours, conserves large amounts of good water otherwise needed for flushing, and reduces the safety risk to the public during activation of new water lines.

Claims

1. A tri valve backflow prevention apparatus for use with a temporary conventional backflow prevention assembly between existing water main pipe and water main pipe under construction, and which permits activation of the water main pipe under construction and removal of the conventional temporary backflow prevention assembly without water in the water main pipe under construction being drained after its required pressure and bacterial testing is successfully completed, and also without the wasteful practice of additional water being needed to flush and refill the emptied water main pipe under construction, and without exposure of the emptied water main pipe under construction to contamination on the construction site and the need for flushing the emptied water main pipe with good drinking water to remove such potential contamination, said tri valve backflow prevention apparatus comprising:

a tri valve housing with a main valve body and two side valves, said main valve body configured for connection between existing water main pipe and water main pipe under construction, and both of said side valves configured for connection to a temporary backflow prevention assembly; and

easily accessible means for opening and closing said main valve and each of said side valves so that during water main construction said main valve body remains closed and said two side valves are allowed to remain open to provide water needed at the construction site via said temporary backflow prevention assembly, and when all construction and testing is completed, said easily accessible opening and closing means are used to close said two side valves and thereafter open said main valve for immediate activation of water main pipe for drinking water delivery to the public and removal of the temporary backflow prevention assembly without causing any water to be drained from the water main pipe under construction.

2. The apparatus of claim 1 wherein said main valve body and said side valves each have valve bodies made from ductile iron encapsulated with EPDM rubber.

3. The apparatus of claim 1 wherein said easily accessible means for opening and closing said main valve and each of said side valves comprises a top seated operating nut and wherein each of said valve bodies further comprises a plurality of nuts and bolts, at least one O-rings, at least one rubber gasket, a valve adjusting stem, and a valve wedge gate.

4. The apparatus of claim 3 wherein said nuts and bolts are made from steel.

5. The apparatus of claim 3 wherein said operating nuts are made from ductile iron.

6. The apparatus of claim 3 wherein said O-rings are made of nitrile rubber.

7. The apparatus of claim 3 wherein said rubber gaskets are made of nitrile rubber.

8. The apparatus of claim 3 wherein said valve adjusting stems are made of manganese bronze.

9. The apparatus of claim 3 wherein said valve wedge gates are made of ductile iron encapsulated with EPDM rubber.

10. The apparatus of claim 3 wherein said nuts and bolts are made from steel, said operating nuts are made from ductile iron, said O-rings are made from nitrile rubber, said rubber gaskets are made from nitrile rubber, said valve adjusting stems are made from manganese bronze, and said valve wedge gates are made of ductile iron encapsulated with EPDM rubber.

11. A method of protecting existing water main pipe and public drinking water during water main construction that allows for connection of water main pipe under construction to existing water main pipe and immediate delivery of good drinking water to the public after construction is complete subsequent to the successful completion of applicable pressure and bacterial testing of the water main pipe under construction without it being drained of water and exposed to possible bacterial contamination during the removal of a temporary backflow prevention assembly used with it during the construction process, said method comprising the steps of:

providing a tri valve backflow prevention apparatus with a main valve body and two side valves, said main valve body configured for connection between existing water main pipe and water main pipe under construction, and both of said side valves configured for connection to a temporary backflow prevention assembly, easily accessible means for opening and closing said main valve and each of said side valves, a temporary backflow preventer assembly, existing water main pipe, water main pipe under construction, and pressure and bacterial testing equipment;

connecting said main valve of tri valve backflow prevention apparatus between said existing water main pipe and said water main pipe under construction;

connecting said temporary backflow prevention assembly to said side valves of said apparatus;

using said opening and closing means to open said side valves and close said main valve body during water main construction;

after said water main construction is complete, using said pressure and bacterial testing equipment to test said water main pipe under construction;

after said pressure and bacterial testing are successfully completed according to applicable standards, using said opening and closing means to close said side valves;

using said opening and closing means to open said main valve body to activate said water main pipe under construction for drinking water delivery to the public; and

removing said temporary backflow prevention assembly without causing any water to be emptied from said water main pipe under construction, and also without the wasteful practice of additional water being needed to flush and refill said water main pipe under construction after being emptied, and without exposure of the emptied water main pipe under construction to contamination on the construction site and the need for flushing said emptied water main pipe with good drinking water to remove such potential contamination.

12. The method of claim 11 wherein the order of accomplishing said steps of using said opening and closing means to open said main valve body to activate said water main pipe under construction and removing said temporary backflow prevention assembly is reversible.

13. The method of claim 11 wherein said main valve body and said side valves each have valve bodies made from ductile iron encapsulated with EPDM rubber.

14. The method of claim 11 wherein said backflow preventer comprises a plurality of nuts and bolts, an operating nut, a plurality of O-rings, a plurality of rubber gaskets, a valve adjusting stem, and a plurality of valve wedge gates.

15. The method of claim 14 wherein said nuts and bolts are made from steel.

16. The method of claim 14 wherein said operating nuts are made from ductile iron.

17. The method of claim 14 wherein said O-rings and rubber gaskets are made of nitrile rubber.

18. The method of claim 14 wherein said valve adjusting stems are made of manganese bronze.

19. The method of claim 14 wherein said valve wedge gates are made of ductile iron encapsulated with EPDM rubber.

20. The method of claim 11 further comprising a step of providing plugging means adapted to seal said side valves, and a step of using said plugging means to plug said side valves after said step of removing said temporary backflow prevention assembly.