Method for detection of a malfunction related to a fluid affected component in a piston machine

• US 8,601,874 B2
• Filed: 04/21/2008
• Issued: 12/10/2013
• Est. Priority Date: 04/30/2007
• Status: Active Grant

• Current Assignee: Grant Prideco Incorporated (NOV, Inc.)
• Original Assignee: National Oilwell Norway AS (NOV, Inc.)
• Inventors: Kyllingstad, Age
• Primary Examiner(s): Williams, Hezron E
• Assistant Examiner(s): Redmann, Gregory J
• Application Number:
  US12/598,401
• Publication Number:
  US 20100189580A1
• Time in Patent Office: 2,059 Days
• Field of Search: 73/405.A, 735/87
• US Class Current: 73/587
• CPC Class Codes: F04B 2201/0802 Vibration
• CPC Class Codes: F04B 2201/1201 Rotational speed of the axis
• CPC Class Codes: F04B 51/00 Testing machines, pumps, or pumping installations
• CPC Class Codes: G01M 13/028 Acoustic or vibration analysis
• CPC Class Codes: G01M 15/12 by monitoring vibrations
• CPC Class Codes: G01M 3/24 using infrasonic, sonic, or ultrasonic vibrations

Abstract

A method for detection of a leak in a fluid affected component of a piston machine includes obtaining a vibration signal from a vibration sensor disposed proximate to at least one valve block of the piston machine. The vibration signal includes vibration generated by valves in the valve block. The method further includes presenting the obtained vibration signal for analysis by at least one of a human or a computer, analyzing the obtained vibration signal with respect to revealing a malfunction related to a fluid affected component of the piston machine, and selecting the obtained vibration signal emitted from the valve block during the closed periods of the valves for presentation.

Claims

1. A method for detection of a leak in a fluid affected component of a piston machine, the method comprising:

attaching a vibration sensor to a valve block of the piston machine;

obtaining a vibration signal from the vibration sensor, wherein the vibration signal comprises vibrations generated by an inlet valve and a discharge valve disposed within the valve block;

presenting the obtained vibration signal for analysis by at least one of a human or a computer;

analyzing the obtained vibration signal to identify a malfunction in the inlet valve or the discharge valve; and

selecting the obtained vibration signal emitted from the valve block during the closed periods of the valves for presentation.

2. The method according to claim 1, wherein the method further includes:

receiving at least one of a rotational speed signal and an angular shaft position signal from a sensor disposed on the piston machine;

calculating an angular shaft position of the piston machine; and

relating the vibration signals from the vibration sensor to the angular shaft position of the piston machine in order to determine at which angle sector of shaft rotation angle corresponds to the malfunction related to a fluid affected component.

3. The method according to claim 2, wherein the method further includes:

determining that the malfunction is a leak in the inlet valve when the vibration continues between an angle α and

an angle β

of a crankshaft of the piston machine.

4. The method according to claim 2, wherein the method further includes:

determining that the malfunction is a leak in the outlet valve when the vibration continues between an angle β and

an angle α

of a crankshaft of the piston machine.

5. The method according to claim 2, wherein the method further includes:

determining that the malfunction is a damaged valve spring in the inlet valve if the valve is closing at a delay after an angle α

respective β

of a crankshaft of the piston machine.

6. The method according to claim 1, wherein the method further includes:

processing the obtained vibration signal from the vibration sensor to suppress vibration signals originating from other sources than the inlet valve and the discharge valve prior to presentation.

7. The method according to claim 1, wherein the method further includes:

processing the obtained vibration signal from the vibration sensor to scale the amplitude prior to presentation.

8. The method according to claim 2, wherein the method further includes:

calculating a root mean square (“

RMS”

) value of the vibrations originating from a leak.

9. The method according to claim 8, wherein the method further includes:

setting an alarm if the RMS value of the vibrations originating from the leak change beyond a preset alarm value.

10. The method according to claim 9, wherein the preset alarm value is a function of the speed of the piston machine.

11. A piston machine, comprising:

a valve block having an inlet valve and a discharge valve disposed therein;

a crankshaft;

a vibration sensor disposed proximate to the valve block;

a computer in communication with the vibration sensor, wherein the computer is configured to select a vibration signal emitted from the vibration sensor during closed periods of the valves and, using at least the vibration signal, determine a leak in the inlet valve or the discharge valve of the piston machine.

12. The piston machine of claim 11, further comprising:

a position sensor configured to render a signal for calculating an angular shaft position and in communication with the computer, wherein the computer is further configured to calculate the angular shaft position of the piston machine and relate the selected vibration signals from the vibration sensor to the angular shaft position of the piston machine in order to determine at which angle sector of shaft rotation angle corresponds to the leak in the inlet valve or the discharge valve.