Apparatus for monitoring a fluid conduit system for leakage points

• US 5,062,442 A
• Filed: 01/08/1990
• Issued: 11/05/1991
• Est. Priority Date: 01/18/1989
• Status: Expired due to Fees

• Current Assignee: Danfoss A/S
• Original Assignee: Danfoss A/S
• Inventors: Molbaek, Jens J., Hyldig, Poul E., Straede, Bjarne, Stenstrom, Theiss
• Primary Examiner(s): Hepperle, Stephen M.
• Application Number:
  US07/461,685
• Time in Patent Office: 666 Days
• Field of Search: 137/110, 137/624.11, 137/624.12, 137/487.5, 137/486, 137/489, 137/579, 137/599.1, 73/202.5, 73/204.26, 73/197
• US Class Current: 137/110
• CPC Class Codes: F17D 5/02 Preventing, monitoring, or locating loss
• CPC Class Codes: Y10T 137/2562 Dividing and recombining
• CPC Class Codes: Y10T 137/7759 Responsive to change in rate of fluid flow

Abstract

The apparatus functions for monitoring small leakages in order to activate an alarm in the event that there has been more than a predetermined volume of small leakage through the water taps or other part of the system and to automatically turn off a main valve if flow continues therethrough more than a predetermined time and will allow the main valve to open if the discharge of fluid is temporary stopped. The system includes a main valve having a valve seat and a shunt circuit that bridges the valve seat. The shunt circuit includes a volume flow meter and a shunt valve for blocking fluid flow through the circuit. The main valve opens only when the volume in the shunt path exceeds a predetermined value. The shunt circuit includes a throttle that when fluid flows therethrough, provides a pressure drop in the shunt circuit which results in the main valve diaphragm opening when the shunt circuit predetermined value is exceeded. Control apparatus ascertains the volume of fluid flow through the measuring portion of the shunt circuit and controls the closing the shunt valve.

Claims

1. Apparatus for monitoring a fluid conduit system for leakage points, comprising a main valve having a housing that includes an inlet, an outlet, and a valve seat interposed between the inlet and outlet, and a fluid flow responsive valve member in the housing operable between an open and a closed position for controlling fluid flow through the valve seat, and volumetric flow meter shunt means for defining a flow shunt flow path that opens to the inlet and outlet, bridging the valve seat and opening to the main valve member for controlling the opening of the valve member as a function of the flow volume in the shunt path and maintaining the main valve member closed until the volume in the shunt path exceeds a predetermined value, the shunt means including a volumetric flow meter for measuring fluid flow through the flow path, an operable shunt valve connected in series with the flow meter between the inlet and outlet for selectively permitting and blocking fluid flow through the flow path, and control means connected and acting at least in part in response to the flow through the flow meter for controlling the operation of the shunt valve.

2. The apparatus according to claim 1, characterized in that the main valve is a power assisted valve controlled by pressure, the valve member being operable between its positions by fluid pressure, and that the shunt means includes a pressure section opening to the valve member for applying fluid pressure to the valve member to retain the valve member in its closed position until flow in the shunt path exceeds the predetermined value and a throttle section disposed between one of the inlet and valve member and the valve member and the outlet.

3. The apparatus according to claim 2 characterized in that the main valve member comprises a diaphragm having a first side abutable against the valve seat for blocking flow through the valve seat and an opposite side exposed to the pressure section in the shut path.

4. The apparatus according to claim 2, characterized in that shunt means includes a shunt valve disposed in the shunt path between the pressure section and the outlet.

5. The apparatus according to claim 1, characterized in that the shunt means includes a measuring section having laminar flow therethrough, a first heat source for heating fluid flowing through the measuring section, detecting means for detecting the temperature of the fluid prior to heating by the heat source, and evaluating means for determining the flow volume from the temperature detected by the detecting means and the amount of heat given off by the heat source.

6. The apparatus of claim 5, characterized in that the detecting means includes first and second temperature sensors, the sensors respectively comprising first and second thin-layer metal foil resistors adapted for having a constant voltage applied thereto with the first resistor being downstream of the second resistor and defining the first heat source, and the second resistor serves to determine the temperature of the fluid.

7. Apparatus for monitoring a fluid conduit system for leakage points, comprising a main valve having a housing that includes an inlet, an outlet, and a valve seat interposed between the inlet and outlet, and a valve member in the housing operable between an open and a closed position for controlling fluid flow through the main valve seat, and volumetric flow meter shunt means for defining a shunt flow path that opens to the inlet and outlet, bridging the valve seat and controlling the opening of the valve member as a function of the flow volume in the shunt path and maintaining the main valve member closed until the volume in the shunt path exceeds a predetermined value, the shunt means including a flow meter having a first shunt section, a valve actuating element having a second shunt section that includes a shunt valve, the shunt valve having a valve seat and a closure member for closing and opening the fluid flow path through the shunt valve seat, an actuating element for controlling the opening and closing of the closure member, and control means for controlling the actuating element, the control means being connected to the flow meter and the actuating element and including an integrator that intermittently integrates the flow through the first shunt section, a measuring section having laminar flow therethrough, a first heat source for heating fluid flowing through the measuring section, detecting means for detecting the temperature of the fluid prior to heating by the heat source, and evaluating means for determining the flow volume from the temperature detected by the detecting means and the amount of heat given off by the heat source, the detecting means including first and second temperature sensors, the sensors respectively comprising first and second thin-layer metal foil resistors adapted for having a constant voltage applied thereto with the first resistor being downstream of the second resistor and defining the first heat source, and the second resistor serving to determine the temperature of the fluid.

8. The apparatus of claim 7, characterized in that the control means includes a resetting circuit for at least one of setting the integrator back and through a predetermined value when the flow volume through the flow meter decreases by a predetermined value.

9. The apparatus of claim 7, characterized in that the control apparatus includes means for feeding the integrator the output value of the flow meter only when the output value exceeds a predetermined first value.

10. The apparatus of claim 7, characterized in that the control means includes means for locking the shunt valve closure member in its closed position when the integrator has detected a first predetermined flow value of the flow through the flow meter and then a second predetermined flow value of flow through the flow meter.

11. The apparatus of claim 7, characterized in that the control means includes means for operating the actuating element to operate the closure member to its closed position after a first predetermined flow value of flow through the flow meter has been determined, then a second predetermined flow value of flow through the flow meter has been determined and thence after a third predetermined flow value of flow through the flow meter that is higher than the second value has been determined.

12. The apparatus of claim 7, characterized in that the control means includes an actuatable display and means for actuating the display when the integrator has detected a predetermined first volume flow through the flow meter.

13. The apparatus of claim 12, characterized in that the control means includes means to reset the integrator to zero after the volume flow through the flow meter has exceeded a first predetermined value and renews an integration if the volume does exceed a predetermined second volume larger than the first volume.

14. Apparatus for monitoring a fluid conduit system for leakage points, comprising a main valve having a housing that includes an inlet, an outlet, and a main valve seat interposed between the inlet and outlet, and a main valve member in the housing operable between an open and a closed position for controlling fluid flow through the valve seat, and volumetric flow meter shunt means acting in cooperation with the housing for defining a shunt flow path that opens to the inlet and outlet for conducting fluid between the inlet and the outlet, bridging the valve seat and controlling the opening of the main valve member as a function of the flow volume in the shunt path and maintaining the main valve member closed until the volume in the shunt path exceeds a predetermined value, the shunt means including a first fluid passage opening to the inlet, a volumetric flow meter that includes a tubular measuring portion having a first end and an a downstream second end portion, a throttle for fluidly connecting the first passage to the measuring portion, a shunt valve that in part defines the flow path and has a shunt valve seat, a second passage fluidly connecting the shunt valve seat to the outlet, a third passage having a first end opening to the shunt valve seat opposite the opening of the second passage to the valve seat and a second end and a shunt valve member operable under fluid pressure for blocking fluid flow from the third passage to the shunt valve seat and thereby though the flow path, and a fluid pressure section fluidly connected to the third passage second end and the measuring portion second end for applying fluid pressure on the main valve member to retain the main valve member in its closed position until the flow through the measuring section exceeds a predetermined value and control means for measuring the volume flow through the measuring section for determining first and second predetermined values of volume flow through the flow meter and applying a pressure to the shunt valve member to move the shunt valve member to its closed position a predetermined interval after the second predetermined value has been reached, the second predetermined value being larger than the first predetermined value.

15. The apparatus of claim 14 further characterized in that the throttle comprises a check valve oriented in a direction to permit fluid flow from the inlet to the measuring portion.

16. Apparatus for monitoring a fluid conduit system for leakage points, comprising a power assisted main valve controlled by pressure and having a housing that includes an inlet, an outlet, and a valve seat interposed between the inlet and outlet, and a valve member in the housing operable under fluid pressure between an open and a closed position for controlling fluid flow through the valve seat, and volumetric flow meter shunt means for defining a shunt flow path that opens to the inlet and outlet, bridging the valve seat and controlling the opening of the valve member as a function of the flow volume in the shunt path and maintaining the main valve member closed until the volume in the shunt path exceeds a predetermined value, the shunt means including a pressure section opening to the valve member for applying fluid pressure to the valve member to retain the valve member in its closed position until flow in the shunt path exceeds the predetermined value and a throttle section disposed between one of the inlet and valve member and the valve member and the outlet, the throttle section comprising a check valve between the inlet and pressure section that opens under fluid pressure in a direction toward the pressure section.

17. Apparatus for monitoring a fluid conduit system for leakage points, comprising a main valve having a housing that includes an inlet, an outlet, and a valve seat interposed between the inlet and outlet, and a valve member in the housing operable between an open and a closed position for controlling fluid flow through the valve seat, and volumetric flow meter shunt means for defining a shunt flow path that opens to the inlet and outlet, bridging the valve seat and controlling the opening of the valve member as a function of the flow volume in the shunt path and maintaining the main valve member closed until the volume in the shunt path exceeds a predetermined value, the shunt means including a measuring section having laminar flow therethrough, a first heat source for heating fluid flowing through the measuring section, detecting means for detecting the temperature of the fluid prior to heating by the heat source, and evaluating means for determining the flow volume from the temperature detected by the detecting means and the amount of heat given off by the heat source, the detecting means including first and second temperature sensors, the sensors respectively comprising first and second thin-layer metal foil resistors adapted for having a constant voltage applied thereto with the first resistor being downstream of the second resistor and defining the first heat source, and the second resistor serving to determine the temperature of the fluid, the measuring section comprising a bent pipe section having an exterior surface, the temperatures sensors being mechanically and thermally connected to the pipe bend exterior surface and being at a predetermined spacing along the pipe section from one another.

18. Apparatus for monitoring a fluid conduit system for leakage points, comprising a main valve having a housing that includes an inlet, an outlet, and a valve seat interposed between the inlet and outlet, and a valve member in the housing operable between an open and a closed position for controlling fluid flow through the valve seat, and volumetric flow meter shunt means for defining a shunt flow path that opens to the inlet and outlet, bridging the valve seat and controlling the opening of the valve member as a function of the flow volume in the shunt path and maintaining the main valve member closed until the volume in the shunt path exceeds a predetermined value, the shunt means including a measuring section having laminar flow therethrough, a first heat source for heating fluid flowing through the measuring section, detecting means for detecting the temperature of the fluid prior to heating by the heat source, and evaluating means for determining the flow volume from the temperature detected by the detecting means and the amount of heat given off by the heat source, the detecting means including first and second temperature sensors, the sensors respectively comprising first and second thin-layer metal foil resistors adapted for having a constant voltage applied thereto with the first resistor being downstream of the second resistor and defining the first heat source, and the second resistor serving to determine the temperature of the fluid, the upstream temperature sensor being an electric resistance that is about 10 times as great as that of the downstream resistor.