System for monitoring backflow preventer condition

Patent metadata

Field	Value
Publication number	US-11427992-B2
Application number	US-202017115872-A
Country	US
Kind code	B2
Filing date	Dec 9, 2020
Priority date	Dec 10, 2019
Publication date	Aug 30, 2022
Grant date	Aug 30, 2022

Abstract

A backflow preventer including a body having an inlet for connection to an upstream portion of a plumbing system and an outlet for connection to a downstream portion of the plumbing system, a first check valve and a second check valve located in the body for preventing the reverse flow of water between the outlet and the inlet. An inlet pressure zone is positioned between the inlet and the first check valve, an outlet pressure zone is positioned between the outlet and the second check valve, and an intermediate pressure zone is positioned between the first and the second check valves. Position sensors sense the positions of the check valves, and pressure sensors sense the pressures in the zone. A controller in communication with the position sensors and the pressure sensors calculates the opening and closing pressures of the check valves.

First claim

The invention claimed is:

1. A backflow preventer for preventing a reverse flow of water in a plumbing system, comprising:
a body having an inlet for connection to an upstream portion of the plumbing
system and an outlet for connection to a downstream portion of the plumbing system;
a first check valve and a second check valve located in the body for preventing the reverse flow of water between the outlet and the inlet;
an inlet pressure zone positioned in the body between the inlet and the first check valve;
an outlet pressure zone positioned in the body between the outlet and the second check valve;
an intermediate pressure zone positioned in the body between the first and the second check valves;
a first position sensor for determining a position of the first check valve; a second position sensor for determining a position of the second check valve;
a first pressure sensor located in the inlet pressure zone;
a second pressure sensor located in the intermediate pressure zone;
a third pressure sensor located in the outlet pressure zone; and
a controller in communication with the position sensors and the pressure sensors,
wherein the controller generates a leak error signal if pressure in the intermediate pressure zone rises while both check valves are in a closed position.

2. The backflow preventer of claim 1 , wherein the controller determines a cracking pressure for each check valve upon opening based upon communications received from the position sensors and the pressure sensors.

3. The backflow preventer of claim 2 , wherein the controller generates an error signal if either cracking pressure is outside a predetermined range.

4. The backflow preventer of claim 2 , wherein the cracking pressure of the first check valve is equal to a difference between the first pressure sensor and the second pressure sensor when the first position sensor detects the first check valve moves from a closed position to an open position.

5. The backflow preventer of claim 1 , wherein the controller determines a closing pressure for each check valve based upon based upon communications received from the position sensors and the pressure sensors.

6. The backflow preventer of claim 5 , wherein the closing pressure of the second check valve is equal to a difference between the third pressure sensor and the second pressure sensor when the second position sensor detects the second check valve moves from an open position to a closed position.

7. The backflow preventer of claim 1 , wherein the controller monitors stiffness of seals of the check valves based upon communications received from the second pressure sensor when the position sensors communicate that the check valves are both in a closed position.

8. The backflow preventer of claim 1 , wherein the controller detects leaks in the downstream portion of the plumbing system based upon communications received from at least one of the pressure sensors and the position sensors.

9. The backflow preventer of claim 1 , wherein:
the first check valve includes a valve seat and a slidably mounted valve disc for sealingly engaging the valve seat to close the first check valve; and
the first position sensor includes a sensor lead having a piezoresistive composite ring sandwiched between two current collector rings, the sensor lead being coupled to the valve seat so that upon closing, pressure from the valve disc transmitted to the sensor lead actuates the first position sensor.

10. The backflow preventer of claim 1 , further comprising a relief valve assembly located between the check valves.

11. A system for monitoring a backflow preventer valve assembly, comprising:
a first position sensor for determining a position of a first check valve of the backflow preventer valve assembly;
a second position sensor for determining a position of a second check valve of the backflow preventer valve assembly;
an intermediate pressure sensor for determining pressure between the check valves;
an outlet pressure sensor for determining pressure at an outlet of the backflow preventer valve assembly; and
a controller in communication with the position sensors and the pressure sensors,
wherein the controller generates a leak error signal if the intermediate pressure sensor indicates a rise in pressure between the check valves while the position sensors communicate that both check valves are in a closed position.

12. A system as recited in claim 11 , further comprising an inlet pressure sensor for determining pressure at an inlet of the backflow preventer valve assembly.

13. A system as recited in claim 11 , wherein the controller determines a cracking pressure for each check valve based upon signals from the position sensors and the pressure sensors.

14. A system as recited in claim 13 , wherein the controller generates an error signal if either cracking pressure is outside a predetermined range.

15. A system as recited in claim 11 , wherein the first position sensor includes a sensor lead having a piezoresistive composite ring sandwiched between two current collector rings.

16. A system as recited in claim 11 , wherein the controller monitors stiffness of seals of the check valves based upon communications received from the pressure sensors when the position sensors communicate that the check valves are both in a closed position.

17. A system as recited in claim 11 , wherein the controller detects leaks in a downstream portion of a plumbing system connected to the outlet of the assembly based upon communications received from at least one of the pressure sensors and the position sensors.

18. A backflow preventer for preventing a reverse flow of water in a plumbing system, comprising:
a body having an inlet for connection to an upstream portion of the plumbing system and an outlet for connection to a downstream portion of the plumbing system;
a first check valve and a second check valve located in the body for preventing the reverse flow of water between the outlet and the inlet;
an inlet pressure zone positioned in the body between the inlet and the first check valve;
an outlet pressure zone positioned in the body between the outlet and the second check valve;
an intermediate pressure zone positioned in the body between the first and the second check valves;
a first position sensor for determining a position of the first check valve;
a second position sensor for determining a position of the second check valve;
a first pressure sensor located in the inlet pressure zone;
a second pressure sensor located in the intermediate pressure zone;
a third pressure sensor located in the outlet pressure zone; and
a controller in communication with the position sensors and the pressure sensors,
wherein: the first check valve includes a valve seat and a slidably mounted valve disc for sealingly engaging the valve seat to close the first check valve; and the first position sensor includes a sensor lead having a piezoresistive composite ring sandwiched between two current collector rings, the sensor lead being coupled to the valve seat so that upon closing, pressure from the valve disc transmitted to the sensor lead actuates the first position sensor.

19. A system for monitoring a backflow preventer valve assembly, comprising:
a first position sensor for determining a position of a first check valve of the backflow preventer valve assembly;
a second position sensor for determining a position of a second check valve of the backflow preventer valve assembly;
an intermediate pressure sensor for determining pressur

Assignees

• Watts Regulator Co

Inventors

• Burke Joseph Michael
• Simon Kevin
• Baynes Ian David

Classifications

• F16K15/066

  with a plurality of valve members · CPC title

• E03B7/077 Primary

  Arrangement of backflow preventing devices · CPC title

• E03C1/106 Primary

  using two or more check valves · CPC title

• F16K37/0025

  Electrical or magnetic means (F16K37/0075 takes precedence) · CPC title

• F16K37/0041

  for measuring valve parameters (F16K37/0033 takes precedence) · CPC title