Method and apparatus for controlling gas flow via a gas shut-off valve assembly

• US 8,701,703 B2
• Filed: 08/09/2010
• Issued: 04/22/2014
• Est. Priority Date: 08/09/2010
• Status: Active Grant

• Current Assignee: Sensus USA Incorporated (Xylem, Inc.)
• Original Assignee: Sensus USA Incorporated (Xylem, Inc.)
• Inventors: Scott, Tim, Steckmann, Dirk, Peace, Daniel W., Vargas, Doug
• Primary Examiner(s): Schneider, Craig
• Assistant Examiner(s): CAHILL, JESSICA MARIE
• Application Number:
  US12/852,684
• Publication Number:
  US 20120031499A1
• Time in Patent Office: 1,352 Days
• Field of Search: 137/557, 137/38, 137/487, 137/488, 137/551, 137/553, 137/554, 137/559, 137/624.11, 137/624.13, 137/624.14, 251/129.04, 251/129.05, 251/68, 251/71, 73/190.5, 738/658, 73/12.3, 700/282, 700/283, 700/79, 700/80
• US Class Current: 137/487
• CPC Class Codes: F16K 31/046 with electric means, e.g. electric switches, to control the motor or to control a clutch between the valve and the motor F16K31/041 takes precedence
• CPC Class Codes: F16K 37/0083 by measuring valve parameters
• CPC Class Codes: F16K 37/0091 by measuring fluid parameters
• CPC Class Codes: Y10T 137/0396 Involving pressure control
• CPC Class Codes: Y10T 137/0753 Control by change of position or inertia of system
• CPC Class Codes: Y10T 137/776 Control by pressures across flow line valve
• CPC Class Codes: Y10T 137/7762 Fluid pressure type
• CPC Class Codes: Y10T 137/8242 Electrical
• CPC Class Codes: Y10T 137/8326 Fluid pressure responsive indicator, recorder or alarm
• CPC Class Codes: Y10T 137/86413 Self-cycling

Abstract

The present invention comprises a method and apparatus for controlling gas flow via a gas shut-off valve assembly. In at least one embodiment, the assembly is configured to drive its shut-off valve from an open position to a closed position, in response to detecting a valve closure condition. The assembly in one or more embodiments operates as an intelligent node in an AMR network, and it interprets a received closure command as a closure condition. Additionally, or alternatively, the assembly detects abnormal operating conditions as the closure condition. Advantageously, the assembly performs initial closure verification, based on detecting movement of the valve into the closed position, and performs subsequent closure verification, based on monitoring downstream gas pressure. In the same or other embodiments, the assembly provides enhanced stand-alone reliability and safety by incorporating one or more valve clearing/cleaning routines into its operations.

Claims

1. A gas shut-off valve assembly comprising:

a valve movable between an open position that permits gas flow through the gas shut-off valve assembly and a closed position that prevents gas flow through the gas shut-off valve assembly;

a motorized drive configured to move the valve between the open and closed positions; and

a control circuit that includes or is associated with a pressure detection circuit and a valve position detection circuit;

wherein said control circuit is configured to close the valve via the motorized drive in response to detecting a closure condition, and is further configured to initially verify valve closure based on directly or indirectly detecting movement of the valve into the closed position, and to subsequently verify valve closure based on monitoring gas pressure on a downstream side of the valve, after said initially verifying valve closure;

wherein the motorized drive includes a stepper motor, and wherein the control circuit is configured to generate stepper motor control signals, for moving the valve between the open and closed positions;

wherein the valve position detection circuit comprises a counting circuit to count stepper motor signal pulses applied to the stepper motor by the control circuit, a back electromotive force (EMF) sensing circuit to sense a back EMF of the stepper motor, and a position inferring circuit configured to infer the position of the valve based on counting stepper motor pulses applied to the stepper motor in conjunction with sensing characteristic changes in the back EMF of the stepper motor at count ranges that are associated with the open and closed positions of the valve; and

wherein the control circuit comprises a microprocessor that includes at least the counting circuit and the position inferring circuit of the valve position detection circuit.

2. The gas shut-off valve assembly of claim 1, wherein the control circuit is configured to communicate via a wireless communication transceiver as an intelligent node in an automated meter reading (AMR) network, including being configured to detect the position of the valve and send a corresponding valve position message, and receive a valve positioning command and position the valve responsive thereto.

3. The gas shut-off valve assembly of claim 1, wherein said control circuit is configured to monitor the gas pressure based on measuring gas pressure at different times and evaluating the measured gas pressure over time, to determine a valve closure status as closed or not closed.

4. The gas shut-off valve assembly of claim 1, wherein the control circuit is configured to send an alarm signal via a wireless communication transceiver of the gas shut-off valve assembly, in response to at least one of detecting an initial or subsequent verification failure, indicating that the valve is not fully closed.

5. The gas shut-off valve assembly of claim 4, wherein the control circuit is configured to interpret receipt of a valve closure command via the wireless communication transceiver as said closure condition, to thereby trigger valve closure.

6. The gas shut-off valve assembly of claim 1, wherein the gas shut-off valve assembly includes one or more environmental condition sensors, each configured to assert an unsafe operating conditions signal, and wherein the control circuit is configured to interpret the assertion of any one of the unsafe operating conditions signals as the closure condition, to thereby trigger valve closure.

7. The gas shut-off valve assembly of claim 6, wherein the one or more environmental condition sensors includes a tilt sensor configured to assert its unsafe operating conditions signal responsive to detecting that the gas shut-off valve assembly is tilted relative to a nominal orientation.

8. The gas shut-off valve assembly of claim 1, wherein the gas shut-off valve assembly includes a body member that is configured for mounting inline with a gas pipe, and wherein said body member defines a fluid passage between an inlet and an outlet of the body member and the valve is configured to act on gas flow through said fluid passage.

9. The gas shut-off valve assembly of claim 8, wherein the gas shut-off valve assembly is configured for horizontal or vertical installation, and wherein the control circuit includes or is associated with a tilt detector and is configured to close the valve responsive to detecting a tilting of the gas shut-off valve assembly away from the horizontal or vertical.

10. A gas shut-off valve assembly comprising:

a valve movable between an open position that permits gas flow through the gas shut-off valve assembly and a closed position that prevents gas flow through the gas shut-off valve assembly;

a motorized drive configured to move the valve between the open and closed positions; and

a control circuit that includes or is associated with a pressure detection circuit and a valve position detection circuit;

wherein said control circuit is configured to close the valve via the motorized drive in response to detecting a closure condition, and is further configured to initially verify valve closure based on directly or indirectly detecting movement of the valve into the closed position, and to subsequently verify valve closure based on monitoring gas pressure on a downstream side of the valve, after said initially verifying valve closure; and

wherein the control circuit is configured to take first and second gas pressure measurements responsive to detecting the valve closure condition, said first gas pressure measurement taken early in a closure cycle when the valve is substantially open, said closure cycle defined by moving the valve from the open position to the closed position, and said second gas pressure measurement taken late in the closure cycle, and is further configured to determine a pressure profile based at least in part on the first and second gas pressure measurements, said pressure profile reflecting an expected, post-closure gas pressure behavior, and wherein said control circuit is configured to monitor the gas pressure subsequent to said initially verifying valve closure based on evaluating measured gas pressures relative to the pressure profile.