Method and apparatus for automatic remote testing of backflow preventers

Claim 1

An apparatus for testing a check valve transversely positioned within a housing, the valve defining an upstream chamber and a downstream chamber therein, said apparatus comprising: a) a flow detector, producing a test initiation signal when at least substantial absence of liquid flowing through the housing is confirmed; b) a first pressure switch in communication with the upstream chamber, said first pressure switch producing a first electrical output signal; c) a second pressure switch in communication with the downstream chamber, said second pressure switch producing a second electrical output signal; d) means responsive to said test initiation signal, for sampling said first and second electrical output signals, and producing a pass/fail report dependent upon a comparison of said signals with a predetermined standard.

Claim 2

An apparatus for testing a check valve transversely positioned within a housing, the valve defining an upstream chamber and a downstream chamber therein, said apparatus comprising: a) a flow detector, producing a test initiation signal when at least substantial absence of liquid flowing through the housing is confirmed; b) a first pressure switch in communication with the upstream chamber, said first pressure switch producing a first electrical output signal; c) a second pressure switch in communication with the downstream chamber, said second pressure switch producing a second electrical output signal; d) means responsive to said test initiation signal, for sampling said first and second electrical output signals, and producing a pass/fail report dependent upon a comparison of said signals with a predetermined standard.

Claim 3

An apparatus for testing a check valve transversely positioned within a housing, the valve defining an upstream chamber and a downstream chamber therein, said apparatus comprising: a) a flow detector, producing a test initiation signal when at least substantial absence of liquid flowing through the housing is confirmed; b) a differential pressure switch having a first port in communication with the upstream chamber, and a second port in communication with the downstream chamber, said switch having electrical contacts and producing an electrical output signal when a predetermined pressure differential exists between said chambers; c) means responsive to said pressure test initiation signal, for sampling said electrical contacts of said pressure switch and producing a pass/fail report depending upon the presence or absence of an output signal.

Claim 4

An apparatus for testing a check valve transversely positioned within a housing, the valve defining an upstream chamber and a downstream chamber therein, said apparatus comprising: a) a flow detector, producing a test initiation signal when at least substantial absence of liquid flowing through the housing is confirmed; b) a differential pressure switch having a first port in communication with the upstream chamber, and a second port in communication with the downstream chamber, said switch having electrical contacts and producing an electrical output signal when a predetermined pressure differential exists between said chambers; c) means responsive to said pressure test initiation signal, for sampling said electrical contacts of said pressure switch and producing a pass/fail report depending upon the presence or absence of an output signal.

Claim 14

An apparatus for testing a check valve transversely positioned within a housing, the valve defining an upstream chamber and a downstream chamber therein, said apparatus comprising: a) a flow detector, producing a test initiation signal when at least substantial absence of liquid flowing through the housing is confirmed; b) a first pressure transducer in communication with the upstream chamber, said first transducer producing a first electrical output signal; c) a second pressure transducer in communication with the downstream chamber, said second transducer producing a second electrical output signal; d) means responsive to said test initiation signal, for subtracting said first electrical signal from said second electrical output signals, and outputting any difference between said signals; e) comparator means, for determining whether said difference outputted from said subtracting means meets a predetermined standard.

Claim 15

An apparatus for testing a check valve transversely positioned within a housing, the valve defining an upstream chamber and a downstream chamber therein, said apparatus comprising: a) a flow detector, producing a test initiation signal when at least substantial absence of liquid flowing through the housing is confirmed; b) a first pressure transducer in communication with the upstream chamber, said first transducer producing a first electrical output signal; c) a second pressure transducer in communication with the downstream chamber, said second transducer producing a second electrical output signal; d) means responsive to said test initiation signal, for subtracting said first electrical signal from said second electrical output signals, and outputting any difference between said signals; e) comparator means, for determining whether said difference outputted from said subtracting means meets a predetermined standard.

Claim 17

An apparatus for testing a check valve transversely positioned within a housing, the valve defining an upstream chamber and a downstream chamber therein, said apparatus comprising: a) a flow detector, producing a test initiation signal when at least substantial absence of liquid flowing through the housing is confirmed; b) a differential pressure transducer having one port in communication with the upstream chamber and another port in communication with the downstream chamber, said transducer producing an electrical output signal corresponding to any differential in pressures between the upstream and downstream chambers; c) comparator means, for determining whether said electrical output from said pressure transducer meets a predetermined standard, and producing a pass/fail report based upon that determination.

Claim 18

An apparatus for testing a check valve transversely positioned within a housing, the valve defining an upstream chamber and a downstream chamber therein, said apparatus comprising: a) a flow detector, producing a test initiation signal when at least substantial absence of liquid flowing through the housing is confirmed; b) a differential pressure transducer having one port in communication with the upstream chamber and another port in communication with the downstream chamber, said transducer producing an electrical output signal corresponding to any differential in pressures between the upstream and downstream chambers; c) comparator means, for determining whether said electrical output from said pressure transducer meets a predetermined standard, and producing a pass/fail report based upon that determination.

Claim 24

An apparatus for testing a combined water flow meter and backflow preventer in which the backflow preventer includes a housing having an upstream check valve and a downstream check valve transversely positioned therein, the upstream check valve defining an upstream chamber and an intermediate chamber therein, and the downstream check valve further defining a downstream chamber therein, said apparatus comprising: a) means responsive to the water flow meter for producing a test initiation signal when at least substantial absence of liquid flowing through the housing is confirmed; b) a first pressure transducer in communication with the upstream chamber, said first transducer producing a first electrical output signal; c) a second pressure transducer in communication with the intermediate chamber, said second transducer producing a second electrical output signal; d) a third pressure transducer in communication with the downstream chamber, said third transducer producing a third electrical output signal; e) means responsive to said test initiation signal, for subtracting said second electrical output signal from said first electrical output signal, and said third electrical output signal from said second electrical output signal, and outputting any respective differences between said signals; f) comparator means, for determining whether said outputs from said subtracting means meets a predetermined standard.

Claim 25

An apparatus for testing a combined water flow meter and backflow preventer in which the backflow preventer includes a housing having an upstream check valve and a downstream check valve transversely positioned therein, the upstream check valve defining an upstream chamber and an intermediate chamber therein, and the downstream check valve further defining a downstream chamber therein, said apparatus comprising: a) means responsive to the water flow meter for producing a test initiation signal when at least substantial absence of liquid flowing through the housing is confirmed; b) a first pressure transducer in communication with the upstream chamber, said first transducer producing a first electrical output signal; c) a second pressure transducer in communication with the intermediate chamber, said second transducer producing a second electrical output signal; d) a third pressure transducer in communication with the downstream chamber, said third transducer producing a third electrical output signal; e) means responsive to said test initiation signal, for subtracting said second electrical output signal from said first electrical output signal, and said third electrical output signal from said second electrical output signal, and outputting any respective differences between said signals; f) comparator means, for determining whether said outputs from said subtracting means meets a predetermined standard.

Claim 26

An apparatus for testing a combined water flow meter and backflow preventer in which the backflow preventer includes a housing having an upstream check valve and a downstream check valve transversely positioned therein, the upstream check valve defining an upstream chamber and an intermediate chamber therein, and the downstream check valve further defining a downstream chamber therein, said apparatus comprising: a) means responsive to the water flow meter for producing a test initiation signal when at least substantial absence of liquid flowing through the housing is confirmed; b) a first differential pressure transducer having port in communication with the upstream chamber and another port in communication with the intermediate chamber, said transducer producing a first electrical output signal having an amplitude corresponding to any differential in pressure between the upstream and intermediate chambers; c) a second differential pressure transducer having one port in communication with the intermediate chamber and another port in communication with the downstream chamber, said transducer producing a second electrical output signal having an amplitude corresponding to any differential in pressure between the intermediate and downstream chambers; d) first comparator means responsive to the test initiation signal, for determining whether the amplitude of said first electrical output signal meets a first predetermined standard; e) second comparator means responsive to the test initiation signal, for determining whether the amplitude of said second electrical output signal meets a second predetermined standard.

Claim 27

An apparatus for testing a combined water flow meter and backflow preventer in which the backflow preventer includes a housing having an upstream check valve and a downstream check valve transversely positioned therein, the upstream check valve defining an upstream chamber and an intermediate chamber therein, and the downstream check valve further defining a downstream chamber therein, said apparatus comprising: a) means responsive to the water flow meter for producing a test initiation signal when at least substantial absence of liquid flowing through the housing is confirmed; b) a first differential pressure transducer having port in communication with the upstream chamber and another port in communication with the intermediate chamber, said transducer producing a first electrical output signal having an amplitude corresponding to any differential in pressure between the upstream and intermediate chambers; c) a second differential pressure transducer having one port in communication with the intermediate chamber and another port in communication with the downstream chamber, said transducer producing a second electrical output signal having an amplitude corresponding to any differential in pressure between the intermediate and downstream chambers; d) first comparator means responsive to the test initiation signal, for determining whether the amplitude of said first electrical output signal meets a first predetermined standard; e) second comparator means responsive to the test initiation signal, for determining whether the amplitude of said second electrical output signal meets a second predetermined standard.

Claim 28

An apparatus for testing a check valve transversely positioned within a housing, the valve defining an upstream chamber and a downstream chamber therein, said apparatus comprising: a) a flow detector, producing a test initiation signal when at least substantial absence of liquid flowing through the housing is confirmed; b) a first pressure sensor in communication with the upstream chamber, said first transducer producing a first electrical output signal; c) a second pressure sensor in communication with the downstream chamber, said second transducer producing a second electrical output signal; d) means responsive to said test initiation signal for sampling said first and second electrical output signals, and producing a pass/fail report dependent upon a comparison of said signals with a predetermined standard.

Claim 29

An apparatus for testing a check valve transversely positioned within a housing, the valve defining an upstream chamber and a downstream chamber therein, said apparatus comprising: a) a flow detector, producing a test initiation signal when at least substantial absence of liquid flowing through the housing is confirmed; b) a first pressure sensor in communication with the upstream chamber, said first transducer producing a first electrical output signal; c) a second pressure sensor in communication with the downstream chamber, said second transducer producing a second electrical output signal; d) means responsive to said test initiation signal for sampling said first and second electrical output signals, and producing a pass/fail report dependent upon a comparison of said signals with a predetermined standard.

Claim 30

An apparatus for testing a backflow preventer in which the backflow preventer includes a housing having an upstream check valve and a downstream check valve transversely positioned therein, the upstream check valve defining an upstream chamber and an intermediate chamber therein, and the downstream check valve further defining a downstream chamber therein, said apparatus comprising: a) a water flow switch or meter in communication with liquid flowing through the housing, said switch producing an output in response to the flow of water; b) a first differential pressure switch having one port in communication with the upstream chamber and another port in communication with the intermediate chamber, said switch producing a first electrical output signal providing a first predetermined pressure differential exists between the upstream and intermediate chambers; c) a second differential pressure switch having one port in communication with the intermediate chamber and another port in communication with the downstream chamber, said switch producing a second electrical output signal providing a second pressure differential exists between the intermediate and downstream chambers; d) means responsive to the output from said water flow meter or switch, and producing a test initiation signal when the water flow is substantially zero; and, e) means responsive to said test initiation signal, for sampling said first and second electrical output signals, and producing a pass/fail report in response thereto.

Claim 31

An apparatus for testing a backflow preventer in which the backflow preventer includes a housing having an upstream check valve and a downstream check valve transversely positioned therein, the upstream check valve defining an upstream chamber and an intermediate chamber therein, and the downstream check valve further defining a downstream chamber therein, said apparatus comprising: a) a water flow switch or meter in communication with liquid flowing through the housing, said switch producing an output in response to the flow of water; b) a first differential pressure switch having one port in communication with the upstream chamber and another port in communication with the intermediate chamber, said switch producing a first electrical output signal providing a first predetermined pressure differential exists between the upstream and intermediate chambers; c) a second differential pressure switch having one port in communication with the intermediate chamber and another port in communication with the downstream chamber, said switch producing a second electrical output signal providing a second pressure differential exists between the intermediate and downstream chambers; d) means responsive to the output from said water flow meter or switch, and producing a test initiation signal when the water flow is substantially zero; and, e) means responsive to said test initiation signal, for sampling said first and second electrical output signals, and producing a pass/fail report in response thereto.

Claim 32

An apparatus for testing a backflow preventer in which the backflow preventer includes a housing having an upstream check valve and a downstream check valve transversely positioned therein, the upstream check valve defining an upstream chamber and an intermediate chamber therein, and the downstream check valve further defining a downstream chamber therein, said apparatus comprising: a) a water flow detector in communication with liquid flowing through the housing, said detector producing an output in response to the flow of water; b) a differential pressure sensor having one port in communication with the upstream chamber and another port in communication with the intermediate chamber, said sensor producing an electrical output signal providing a predetermined pressure differential exists between the upstream and intermediate chambers; c) a pressure relief valve having a first inlet and a second inlet, said relief valve including an inlet line interconnecting said first inlet and said upstream chamber, said second inlet being in communication with said intermediate chamber, said relief valve further including a discharge port in communication with the atmosphere; d) a by-pass test line interconnecting said upstream chamber and said intermediate chamber, said test line including an electrically actuated valve selectively operable from a first closed position in which said test line is obstructed, to a second open position in which pressure from said upstream chamber is introduced into said intermediate chamber; e) means responsive to the output from said water flow detector, and producing a test initiation signal when the water flow is substantially zero; f) means responsive to said test initiation signal, for sampling said electrical output signal and comparing it to a predetermined value, and producing a pressure relief valve pass/fail report in response thereto.

Claim 33

An apparatus for testing a backflow preventer in which the backflow preventer includes a housing having an upstream check valve and a downstream check valve transversely positioned therein, the upstream check valve defining an upstream chamber and an intermediate chamber therein, and the downstream check valve further defining a downstream chamber therein, said apparatus comprising: a) a water flow detector in communication with liquid flowing through the housing, said detector producing an output in response to the flow of water; b) a differential pressure sensor having one port in communication with the upstream chamber and another port in communication with the intermediate chamber, said sensor producing an electrical output signal providing a predetermined pressure differential exists between the upstream and intermediate chambers; c) a pressure relief valve having a first inlet and a second inlet, said relief valve including an inlet line interconnecting said first inlet and said upstream chamber, said second inlet being in communication with said intermediate chamber, said relief valve further including a discharge port in communication with the atmosphere; d) a by-pass test line interconnecting said upstream chamber and said intermediate chamber, said test line including an electrically actuated valve selectively operable from a first closed position in which said test line is obstructed, to a second open position in which pressure from said upstream chamber is introduced into said intermediate chamber; e) means responsive to the output from said water flow detector, and producing a test initiation signal when the water flow is substantially zero; f) means responsive to said test initiation signal, for sampling said electrical output signal and comparing it to a predetermined value, and producing a pressure relief valve pass/fail report in response thereto.

Claim 36

A method for testing a backflow preventer in which the backflow preventer includes a housing having an upstream check valve and a downstream check valve transversely positioned therein, the upstream check valve defining an upstream chamber and an intermediate chamber, and the downstream check valve further defining a downstream chamber therein, said method comprising the steps of: a) sampling the interior of the housing and producing a test initiation signal when at least substantial absence of liquid flowing through the housing is confirmed; b) sampling the liquid pressure within the upstream chamber, and producing a first electrical output signal in response thereto; c) sampling the liquid pressure within the intermediate chamber, and producing a second electrical output signal in response thereto; d) sampling the liquid pressure within the downstream chamber, and producing a third electrical output signal in response thereto; e) determining whether said first and second electrical output signals and said second and third electrical output signals, bear a predetermined relationship, to at least one predetermined standard; f) producing a pass/fail report for at least one of said valves, based upon the determinations of step e.

Claim 37

A method for testing a backflow preventer in which the backflow preventer includes a housing having an upstream check valve and a downstream check valve transversely positioned therein, the upstream check valve defining an upstream chamber and an intermediate chamber, and the downstream check valve further defining a downstream chamber therein, said method comprising the steps of: a) sampling the interior of the housing and producing a test initiation signal when at least substantial absence of liquid flowing through the housing is confirmed; b) sampling the liquid pressure within the upstream chamber, and producing a first electrical output signal in response thereto; c) sampling the liquid pressure within the intermediate chamber, and producing a second electrical output signal in response thereto; d) sampling the liquid pressure within the downstream chamber, and producing a third electrical output signal in response thereto; e) determining whether said first and second electrical output signals and said second and third electrical output signals, bear a predetermined relationship, to at least one predetermined standard; f) producing a pass/fail report for at least one of said valves, based upon the determinations of step e.

Claim 38

A method for testing a check valve transversely positioned within a housing, the valve defining an upstream chamber and a downstream chamber therein, said method comprising the steps of: a) producing a test initiation signal when at least substantial absence of liquid flowing through the housing is confirmed; b) sampling the liquid pressure within the upstream chamber, in response to the test initiation signal; c) sampling the liquid pressure within the downstream chamber, in response to the test initiation signal; d) producing a pass report or a fail report, depending on whether or not a pressure differential exists between said samples of said upstream and downstream chambers, which differential meets a predetermined standard.

Claim 39

A method for testing a check valve transversely positioned within a housing, the valve defining an upstream chamber and a downstream chamber therein, said method comprising the steps of: a) producing a test initiation signal when at least substantial absence of liquid flowing through the housing is confirmed; b) sampling the liquid pressure within the upstream chamber, in response to the test initiation signal; c) sampling the liquid pressure within the downstream chamber, in response to the test initiation signal; d) producing a pass report or a fail report, depending on whether or not a pressure differential exists between said samples of said upstream and downstream chambers, which differential meets a predetermined standard.