Method and apparatus for diagnosing a pump system

• US 6,330,525 B1
• Filed: 08/02/2000
• Issued: 12/11/2001
• Est. Priority Date: 12/31/1997
• Status: Expired due to Fees

• Current Assignee: Innovation Management Group, Inc.
• Original Assignee: Innovation Management Group, Inc.
• Inventors: Lenz, Gary A., Hays, Coy L.
• Primary Examiner(s): Shah, Kamini
• Application Number:
  US09/631,094
• Time in Patent Office: 496 Days
• Field of Search: 702/183, 702/182, 376/245, 376/246, 376/247, 376/249, 73/540.1
• US Class Current: 702/183
• CPC Class Codes: F04D 15/0088 Testing machines
• CPC Class Codes: G05B 23/0235 based on a comparison with predetermined threshold or range, e.g. "classical methods", carried out during normal operation; threshold adaptation or choice; when or how to compare with the threshold

Abstract

An apparatus and method for diagnosing rotating equipment commonly used in the factory and process control industry are provided. The apparatus and method are intended for use in assisting a maintenance engineer in the diagnosis of turbines, compressors, fans, blowers and pumps. The preferred embodiments are an apparatus and method for diagnosing pumps, with a focus on centrifugal pumps. The apparatus and method are based on the comparison of the current pump signature curves resulting from the acquisition of process variables from sensors monitoring the current condition of the pump and the original or previous pump performance curve from prior monitoring or knowledge of the pump geometry, installation effects and properties of the pumped process liquid. The diagnostic apparatus and method can be applied to any rotating machine, but the apparatus and method for pumps are described herein.

Claims

1. An apparatus for diagnosing a power system which includes a rotating machine, the apparatus comprising:

process sensors for generating process variables, said process sensors including;

an outlet pressure sensor positioned proximate an outlet of the rotating machine for determining rotating machine outlet pressure; and

a flow meter for determining a flow rate of product downstream of the rotating machine;

said apparatus further including;

an input/output device in communication with said process sensors for receiving process variables from said process sensors; and

a computing device in communication with said input/output device, said computing device having a memory, said memory for storing data from said input/output device, said computing device for receiving original data including tables of machine geometry, machine installation parameters, original performance curves and fluid properties of said pumped product, said computing device for comparing said process variables with said original data and for generating an output based upon said comparison.

2. An apparatus according to claim 1, including machine sensors for generating condition monitoring variables, said machine sensors comprising:

a rotating machine vibration sensor mounted on the rotating equipment for determining vibration of the rotating machine, said vibration sensor in communication with said input/output device for providing condition monitoring variables thereto; and

said computing device for comparing said condition monitoring variables with said original data for diagnosis of rotating equipment degradation and for generating an output based upon said comparison.

3. The apparatus according to claim 2, wherein said machine sensors further comprise:

a gear box vibration sensor mounted on a gear box for determining gear box vibration; and

a motor supply sensor mounted on electrical power supply service for determining electrical power to a motor;

an alignment sensor mounted on the motor for determining coupler alignment;

wherein said motor vibration sensor, said alignment sensor, said gear box sensor and said motor supply sensor are for providing condition monitoring variables to said input/output device for providing said computing device with condition monitoring variables to diagnose the rotating machine and alert an operator of impending rotating machine maintenance.

4. The apparatus according to claim 2, wherein said machine sensors further comprise a rotating machine seal leakage sensor mounted proximate a shaft seal on the rotating machine for detecting seal leakage, said rotating machine seal leakage sensor for providing condition monitoring variables to said input/output device for providing said computing device with condition monitoring variables.

5. The apparatus according to claim 2, wherein said machine sensors further comprise an oil contamination sensor mounted in a gearbox or on an oil sump for detecting oil contamination, said oil contamination sensor for providing conditioning monitoring variables to said input/output device for providing said computing device with condition monitoring variables.

6. The apparatus according to claim 2, wherein said machine sensors further comprise a viscosity degradation sensor mounted proximate a gearbox for detecting oil viscosity degradation, said viscosity degradation sensor for providing condition monitoring variables to said input/output device for providing said computing device with an oil condition monitoring variable.

7. The apparatus according to claim 2, wherein said machine sensors further comprise a dynamic sensor mounted on a pump casing for measuring pressure noise in said pump casing for providing condition monitoring variables to said input/output device for providing said condition monitoring variables to said computing device for diagnosing pump recirculation and cavitation.

8. The apparatus according to claim 2, further comprising a valve position sensor mounted on said control valve and in communication with said input/output device, said valve position sensor for determining a position of a shaft of said control valve.

9. The apparatus according to claim 2, wherein said machine sensors further comprise an corrosion sensor mounted on a rotating machine casing for measuring the degradation of the rotating machine casing from corrosion, pump cavitation or erosion, said corrosion sensor in communication with said input/output device for providing condition monitoring variables thereto.

10. The apparatus according to claim 2, wherein said machine sensors further comprise an ultrasonic thickness sensor mounted on a rotating machine casing for measuring the degradation of the rotating equipment casing from corrosion, pump cavitation or erosion, said ultrasonic thickness sensor in communication with said input/output device for providing condition monitoring variables thereto.

11. The apparatus according to claim 2, wherein said machine sensors are integrated with said input/output device and said computing device for comparing measured performance signatures of the rotating machine at a second time with an original condition signature at a first time, for diagnosing degradation of the rotating machine.

12. The apparatus according to claim 2, wherein said machine sensors further comprise:

a torque sensor mounted on a shaft of said rotating machine, said torque sensor in communication with said input/output device for providing said computing device with torque data;

an angular velocity sensor mounted on a shaft of said rotating machine, said angular velocity sensor in communication with said input/output device for providing said computing device with angular velocity data for computing input power to the rotating machine, speed of the rotating machine, and rotating machine efficiency.

13. The apparatus according to claim 2, wherein said computing device serves as a host, said host in communication with a controller proximate the rotating machine for controlling the rotating machine, said microcontroller having firmware for providing control set point to said rotating machine.

14. The apparatus according to claim 2, wherein said computing device is positioned proximate a rotating machine, said computing device for providing a control set point for said rotating machine.

15. The apparatus according to claim 2, further comprising a communication port for importing condition monitoring variables from a portable handheld data logging device.

16. The apparatus according to claim 2, further comprising a process variable digital bus in communication with networked intelligent devices.

17. The apparatus according to claim 2, further comprising a monitoring system digital bus in communication with intelligent network devices with a computing device for collecting said condition monitoring variables.

18. The apparatus according to claim 2, further comprising condition monitoring subsystems for the rotating machine, said condition monitoring subsystems interfaced with the computing device via standard communication network interfaces for transmitting subsystem data over a standard communication network.

19. Apparatus according to claim 18, further comprising an external processed data storage device for storing the subsystem data wherein the apparatus is a network client having a memory database for storing data from a networked rotating machine subsystem.

20. The apparatus according to claim 2, further comprising a co-processor in communication with said computing device for providing spectral signal reduction of said condition monitoring variables from said vibration sensor, said motor vibration sensor, said dynamic pressure sensor and said bearing vibration sensor.

21. An apparatus according to claim 1, wherein said process sensors further comprise:

an inlet pressure sensor positioned proximate an intake of the rotating machine for determining rotating machine inlet pressure; and

a temperature sensor positioned upstream or downstream of the rotating machine for determining temperature of a process fluid.

22. The apparatus according to claim 1, further comprising an alert device for indicating when undesirable equipment conditions occur.

23. The apparatus according to claim 22, further comprising a contact closure for shutting down the apparatus when said alert device indicates an undesirable equipment condition.

24. An apparatus according to claim 1, further comprising a final control element, said final control element responsive to said output for adjusting the rotating machine and motor system for operating the rotating machine in a recognized recommended operating design regime.

25. An apparatus according to claim 24 wherein said final control element is a control valve downstream of said rotating machine for regulating back pressure.

26. An apparatus according to claim 24, wherein said final control element is a variable speed drive coupled to the motor, said variable speed drive for adjusting motor speed.

27. The apparatus according to claim 1, further comprising a real time clock in communication with said computing device for time stamping process variables and said original data for time based comparison.

28. The apparatus according to claim 1, further comprising a display for representing a performance signature at a first time and a second time.

29. The apparatus according to claim 1, further comprising a co-processor with a spectral analysis engine for processing signals from frequency domain sensors.

30. The apparatus according to claim 1, further comprising a network communication port in communication with said input/output device, said network communication port for communicating said output to a network.

31. An apparatus according to claim 1, further comprising a communication device for communicating data from said computing device to a networked host.

32. The apparatus according to claim 1, wherein said computing device is powered by and communicates over two wires.

33. The apparatus according to claim 1, wherein said computing device is powered by and communicates with either 3-wire or 4-wire networks.

34. The apparatus according to claim 1 including multiplexer inputs in order to diagnose more than one said rotating machine.