Sense and hold circuit for hose assembly

• US 9,535,024 B2
• Filed: 09/13/2013
• Issued: 01/03/2017
• Est. Priority Date: 09/14/2012
• Status: Active Grant

• Current Assignee: Danfoss A/S
• Original Assignee: Eaton Corp. (Wisconsin) (Eaton Corporation PLC.)
• Inventors: Burtyk, Nicholas Adam, Betsinger, James Dean
• Primary Examiner(s): He, Amy
• Application Number:
  US14/026,091
• Publication Number:
  US 20140076449A1
• Time in Patent Office: 1,208 Days
• Field of Search: 324/522, 324/525, 324/713
• US Class Current: 1/1
• CPC Class Codes: F16L 11/00 Hoses, i.e. flexible pipes
• CPC Class Codes: F16L 2201/30 Detecting leaks
• CPC Class Codes: G01M 3/18 for pipes, cables or tubes; for pipe joints or seals; for valves; for welds; for containers, e.g. radiators
• CPC Class Codes: G01M 5/0025 of elongated objects, e.g. pipes, masts, towers or railways G01M5/0058 takes precedence
• CPC Class Codes: G01M 5/0033 by determining damage, crack or wear
• CPC Class Codes: G01M 5/0083 by measuring variation of impedance, e.g. resistance, capacitance, induction
• CPC Class Codes: G01N 27/045 Circuits measuring resistance per se G01R27/00, e.g. G01R27/22
• CPC Class Codes: G01R 27/02 Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant by measuring phase angle only G01R25/00
• CPC Class Codes: G08B 21/182 Level alarms, e.g. alarms responsive to variables exceeding a threshold

Abstract

A monitoring circuit for detecting degradation of a hose assembly a hose assembly and a hose assembly incorporating such a monitoring circuit are disclosed. The monitoring circuit includes a voltage source connected to a first connection location of a hose assembly. A capacitor is electrically connected between the second connection location connected to the second conductive layer of a hose assembly and a ground. The capacitor is selected such that a change in resistance of the hose assembly changes a voltage carried by the capacitor. The monitoring circuit includes a voltage sampling circuit configured to periodically detect a voltage at the capacitor. Upon detecting a change in the voltage above a predetermined threshold, the voltage sampling circuit generates an alarm indicative of potential failure.

Claims

1. A monitoring circuit configured to detect degradation of a hose assembly, the circuit comprising:

a voltage source connected to a first connection location of a hose assembly, the hose assembly including a hose having a first conductive layer and a second conductive layer, the first connection location electrically connected to the first conductive layer, wherein the second connection location is electrically connected to ground;

a capacitor electrically connected to the hose assembly via a differential voltage detection circuit, wherein a difference between a voltage at the voltage source and a voltage across the hose is captured by the capacitor;

a voltage sampling circuit configured to periodically detect a voltage at the capacitor, wherein, upon detecting a change in the voltage above a predetermined threshold, the voltage sampling circuit is configured to generate an alarm indicative of potential failure of the hose assembly.

2. The circuit of claim 1, further comprising a differential amplifier electrically connected between the first connection location and the capacitor, the differential amplifier configured to scale the voltage differences on the capacitor based on changes in the resistance.

3. The circuit of claim 2, wherein the differential amplifier is configured to, in the event of a short duration lowering of the resistance of the hose assembly, provide a voltage to the capacitor such that the capacitor retains additional voltage thereon.

4. The circuit of claim 2, further comprising a diode connected between an output of the differential amplifier and the capacitor.

5. The circuit of claim 1, wherein the voltage sampling circuit is configured to, upon detection that the voltage is above the predetermined threshold, clear the additional voltage from the capacitor.

6. The circuit of claim 5, wherein the voltage sampling circuit is configured to clear the additional voltage from the capacitor after generating the alarm.

7. The circuit of claim 1, wherein the resistance comprises a resistance value during an event experienced by the hose.

8. The circuit of claim 7, wherein the event comprises an impulse event occurring at a time different from a time at which the voltage sampling circuit periodically detects voltage at the capacitor.

9. The circuit of claim 1, wherein the voltage sampling circuit comprises a microcontroller.

10. The circuit of claim 1, further comprising a communication circuit communicatively connected to the voltage sampling circuit and configured to, upon receiving a signal from the voltage sampling circuit regarding the alarm, communicate the alarm remotely from the hose assembly.

11. The circuit of claim 10, wherein the communication circuit comprises a wireless communication interface.

12. The circuit of claim 1, wherein the first connection location comprises a nipple of the hose assembly and the second connection location comprises a socket of the hose assembly.

13. A method of monitoring a hose assembly, the method comprising:

applying a voltage to a first electrical connection of a hose assembly, the hose assembly including a hose having a first conductive layer and a second conductive layer, the first conductive layer electrically connected to the first connection location and the second conductive layer electrically connected to a second connection location that is connected to ground, and wherein the first and second conductive layers are separated by an insulating layer;

periodically monitoring a capacitor electrically connected at the first connection location by a differential voltage detection circuit, the capacitor forming a portion of a sense and hold circuit;

upon detecting a voltage at the capacitor above a predetermined threshold, generating an alarm indicating a potential failure of the hose assembly.

14. The method of claim 13, further comprising communicating the alarm to a location remote from the hose assembly.

15. The method of claim 13, further comprising clearing the voltage at the capacitor to a level below the predetermined threshold.

16. The method of claim 13, wherein applying the voltage comprises applying a continuous voltage.

17. The method of claim 13, wherein the first connection location is at a nipple and the second connection location is at a socket.

18. An integrated hose assembly having a monitoring system, the integrated hose assembly comprising:

a hose assembly having a first conductive layer electrically connected to a nipple and a second conductive layer electrically connected to a socket, the first and second conductive layers separated by an insulating layer;

a monitoring circuit applied to the hose assembly and across the nipple and socket, the monitoring circuit including;

a voltage source connected to a first connection location of a hose assembly, the hose assembly including a hose having a first conductive layer and a second conductive layer, the first connection location electrically connected to the first conductive layer, wherein the second connection location is electrically connected to ground;

a capacitor electrically connected to the hose assembly via a differential voltage detection circuit, wherein a difference between a voltage at the voltage source and a voltage across the hose is captured by the capacitor;

a voltage sampling circuit configured to periodically detect a voltage at the capacitor, wherein, upon detecting a change in the voltage above a predetermined threshold, the voltage sampling circuit is configured to generate an alarm indicative of potential failure of the hose assembly.

19. The integrated hose assembly of claim 18, wherein the voltage source is applied continuously across a circuit including connections to the nipple and socket.

20. The integrated hose assembly of claim 18, wherein the differential voltage detection circuit comprises a differential amplifier.

21. The integrated hose assembly of claim 18, wherein the monitoring circuit further includes:

a first pair of contacts electrically contacting the first connection location of a hose assembly;

a second pair of contacts electrically contacting the second connection location of a hose assembly;

a circuit electrically connected to the first pair contacts and configured to obtain a first resistance between the first pair of contacts;

wherein the circuit is electrically connected to the second pair contacts and configured to obtain a second resistance between the second pair of contacts; and

wherein the voltage sampling circuit includes a control circuit configured to compare the first and second resistances to a threshold value.

22. The monitoring circuit of claim 21, wherein the control circuit is further configured to, upon detecting that the first or second resistances exceed the threshold value, generate an alarm.

23. The monitoring circuit of claim 21, wherein the control circuit is further configured to detect a resistance between the first connection location and the second connection location by detecting an overall resistance at the circuit and at least partially compensating for the first and second resistances.