Motorized valve diagnosing method and device

• US 20080006101A1
• Filed: 03/10/2004
• Published: 01/10/2008
• Est. Priority Date: 03/10/2003
• Status: Active Grant

• Current Assignee: Shikoku Research Institute, Inc. (Shikoku Electric Power Company Incorporated)
• Original Assignee: Shikoku Research Institute, Inc. (Shikoku Electric Power Company Incorporated)
• Inventors: Nogami, Takeki, Yamaguchi, Shigeya
• Granted Patent: US 7,516,656 B2
• Time in Patent Office: Days
• US Class Current: 73/865.9
• CPC Class Codes: F16K 37/0083 by measuring valve parameters

Abstract

A diagnostic method and apparatus for diagnosing a motor-operated valve capable of continuously measuring a preload of a spring cartridge at low costs, with high accuracy, and with ease, so that the elastic characteristics of the spring cartridge may be easily calibrated in a simple manner. The method and apparatus is for diagnosing a motor-operated valve including a valve disc 25, a worm 12 rotatably driven by motor power, a link mechanism which opens and closes the valve disc 25 with the rotational driving force transmitted from the worm 12, and a spring cartridge 13 containing disc springs 15 which expand or compress in response to reaction force acting on the worm 12 in its axial direction from the link mechanism. The method and apparatus calibrates the torque curve representing the elastic characteristics the spring cartridge 13 based on the load corresponding to a specific compression condition of the spring cartridge 13, and based on the torque curve thus calibrated, produces a diagnosis of the motor-operated valve. Accordingly, an easy and quick diagnosis can be achieved on whether the torque-related characteristics of the motor-operated valve are appropriate or not.

Claims

1. A motor-operated valve diagnostic method for diagnosing a motor-operated valve comprising a valve disc for opening and closing a given passage, a worm rotatably driven by motor power, a link mechanism which opens and closes the valve disc with the rotational driving force transmitted from the worm, and a spring cartridge containing disc springs which expand or compress in response to reaction force acting on the worm in its axial direction from the link mechanism, said method being characterized in that a torque curve representing the elastic characteristics of the spring cartridge is calibrated based on a load corresponding to a specific compression condition of the spring cartridge and in that the motor-operated valve is diagnosed based on the torque curve thus calibrated.

2. The motor-operated valve diagnostic method as claimed in claim 1, characterized in that the load corresponding to the specific compression condition of the spring cartridge includes at least a preload of the spring cartridge.

3. The motor-operated valve diagnostic method as claimed in claim 1, characterized in that a condition of compression of the spring cartridge resulting from the reaction force is detected as a worm axial displacement, in that a given physical quantity corresponding to a load which corresponds to the specific compression condition of the spring cartridge is detected, and in that the load corresponding to the specific compression condition of the spring cartridge based on the given physical quantity is then detected.

4. The motor-operated valve diagnostic method as claimed in claim 3, characterized in that the worm displacement is detected by monitoring the position of the spring cartridge shaft end moving axially together with the worm or of the peripheral part thereof fixed thereto and moving together therewith.

5. The motor-operated valve diagnostic method as claimed in claim 4, characterized in that the worm displacement is detected by monitoring, by means of a worm position sensor, the position of the spring cartridge shaft end or of the peripheral part thereof fixed thereto and moving together therewith, the worm position sensor being mounted on the motor-operated valve with the use of an adaptor, the adapter being placed between the worm position sensor and the motor-operated valve, replacing the cover covering the spring cartridge and having an insertion length substantially identical to that of the cover.

6. The motor-operated valve diagnostic method as claimed in claim 3, characterized in that the aforementioned given physical quantity is the stress acting on the link mechanism or the reaction stress generated in an area subjected to the stress acting on the link mechanism when the spring cartridge is under the specific compression condition;

and in that a reference is made to the pre-established corresponding relation between the stress or reaction stress and the load acting on the spring cartridge so that the load corresponding to the specific compression condition of the spring cartridge can be detected based on the stress or reaction stress.

7. The motor-operated valve diagnostic method as claimed in claim 6, characterized in that an area subjected to the stress includes the yoke covering the link mechanism, the spring cartridge, or other area where stress changes integrally with that in the spring cartridge.

8. The motor-operated valve diagnostic method as claimed in claim 3, characterized in that the aforementioned given physical quantity is the elapsed time between a given reference time and the starting time of the worm displacement;

and in that a reference is made to the corresponding relation between the elapsed time and the load acting on the spring cartridge so that the preload of the spring cartridge can be detected based on the elapsed time.

9. The motor-operated valve diagnostic method as claimed in claim 8, characterized in that the aforementioned given reference time is the time of the valve disc-to-seat contact.

10. The motor-operated valve diagnostic method as claimed in claim 9, characterized in that the time of the valve disc-to-seat contact is detected based on a change in stress acting on the link mechanism or a change in reaction stress generated in an area subjected to the stress acting on the link mechanism, for example, the yoke covering the link mechanism, the spring cartridge, or an area where stress changes integrally with that in the spring cartridge.

11. The motor-operated valve diagnostic method as claimed in claim 1, characterized in that the elastic characteristics of the spring cartridge is further determined by an externally-attached torque sensor, a spring pressing device, or a spring cartridge calibrator.

12. The motor-operated valve diagnostic method as claimed in claim 1, characterized in that when a hysteresis exists in the elastic characteristics of the spring cartridge between the valve disc closing movement from the full open position and the valve disc opening movement from the full close position, a spring pressing device added with the function of an externally-attached torque sensor is used to determine the elastic characteristics of the spring cartridge in such a manner that the elastic characteristics of the spring cartridge for the valve disc opening movement from the full close position are determined by means of the spring pressing device, while the elastic characteristics of the spring cartridge for the valve disc closing movement from the full open position are determined by the function of an externally-attached torque sensor, with the motor-operated valve in operation.

13. A motor-operated valve diagnostic apparatus for diagnosing a motor-operated valve, the motor-operated valve comprising a valve disc for opening and closing a given passage, a worm rotatably driven by motor power, a link mechanism which opens and closes the valve disc with the rotational driving force transmitted from the worm, and a spring cartridge containing disc springs which expand or compress in response to reaction force acting on the worm in its axial direction from the link mechanism, the apparatus being characterized by comprising a diagnostic device which calibrates the torque curve representing the elastic characteristics of the spring cartridge based on a load corresponding to a specific compression condition of the spring cartridge and including at least the preload of the spring cartridge and which then produces a diagnosis of the motor-operated valve based on the torque curve thus calibrated.

14. The motor-operated valve diagnostic apparatus as claimed in claim 13, characterized by further comprising a worm position sensor for detecting a condition of compression of the spring cartridge, which results from the aforementioned reaction force, as a worm axial displacement, and a stress sensor for detecting stress acting on the link mechanism or reaction stress generated in an area subjected to the stress acting on the link mechanism, wherein the aforementioned diagnostic device is configured to detect a load corresponding to the specific compression condition of the spring cartridge based on the stress detected by the stress sensor when the spring cartridge is under compression condition, the load including at least the preload of the spring cartridge, and the compression condition including at least a compression condition at the starting time of the spring cartridge deformation detected by the worm position sensor.

15. The motor-operated valve diagnostic apparatus as claimed in claim 14, characterized in that the stress sensor is configured to detect the reaction stress generated in the yoke covering the link mechanism, in the spring cartridge, or in an area where stress changes integrally with that in the spring cartridge.

16. The motor-operated valve diagnostic apparatus as claimed in claim 13, characterized by comprising a worm position sensor for detecting the starting time of the spring cartridge deformation, caused by the act of compression thereon resulting from the aforementioned reaction force, as the starting time of the worm axial displacement, and a timer for measuring an elapsed time between a given reference time and the starting time of the spring cartridge deformation, wherein the aforementioned diagnostic device is configured to detect the preload of the spring cartridge based on the elapsed time measured by the timer.

17. The motor-operated valve diagnostic apparatus as claimed in claim 16, characterized in that the aforementioned given reference time is the time when the valve disc contacts the valve seat, and in that the apparatus comprises a stress sensor which detects the time of the valve disc-to-seat contact based on a change in stress acting on the link mechanism or a change in reaction stress generated in an area subjected to the stress acting on the link mechanism, such as the yoke covering the link mechanism, the spring cartridge, or an area where stress changes integrally with that in the spring cartridge.

18. The motor-operated valve diagnostic apparatus as claimed in claim 13, characterized by further comprising an externally-attached torque sensor, a spring pressing device, or a spring cartridge calibrator for detecting the elastic characteristics of the spring cartridge.

19. The motor-operated valve diagnostic apparatus as claimed in claim 13, characterized in that when a hysteresis exists in the elastic characteristics of the spring cartridge between the valve disc closing movement from the full open position and the valve disc opening movement from the full close position, the spring pressing device added with the function of an externally-attached torque sensor is used to determine the elastic characteristics of the spring cartridge in such a manner that the elastic characteristics of the spring cartridge for the valve disc opening movement from the full close position are determined by means of the spring pressing device, while the elastic characteristics of the spring cartridge for the valve disc closing movement from the full open position are determined using the function of an externally-attached torque sensor, with the motor-operated valve in operation.

20. The motor-operated valve diagnostic apparatus as claimed in claim 18, characterized in that the spring pressing device is installed to the motor-operated valve exchangeably with the worm position sensor.

21. The motor-operated valve diagnostic apparatus as claimed in claim 14, characterized in that the worm position sensor is mounted on the motor-operated valve with the use of an adapter, the adapter being placed between the worm position sensor and the motor-operated valve, replacing the cover covering the spring cartridge and having an insertion length almost identical to that of the cover.

22. The motor-operated valve diagnostic apparatus as claimed in claim 13, characterized in that the worm position sensor comprises a laser sensor which detects the position of an object by irradiating a laser beam onto the object and detecting light reflected therefrom.

23. The motor-operated valve diagnostic apparatus as claimed in claim 13, characterized by further comprising an output device for outputting acceptance criteria relating to the diagnostic results or for the diagnostic data together with the diagnostic results and/or diagnostic data.

24. A motor-operated valve diagnostic method for diagnosing a motor-operated valve, the motor-operated valve comprising a valve disc for opening and closing a given passage, a worm rotatably driven by an electromotive force, a link mechanism which opens and closes the valve disc with the rotational driving force transmitted from the worm, and a spring cartridge containing disc springs which expand or compress in response to reaction force acting on the worm in its axial direction from the link mechanism, the method being characterized in that the start of the worm axial displacement resulting from the reaction force is detected, in that a given physical quantity corresponding to the preload of the spring cartridge at the starting time of the worm displacement is detected, and in that a preload of the spring cartridge is detected from the detected physical quantity.

25. The motor-operated valve diagnostic method as claimed in claim 24, characterized in that a torque curve representing the elastic characteristics of the spring cartridge is calibrated based on the detected preload of the spring cartridge, and in that a diagnosis of the motor-operated valve is made based on the torque curve thus calibrated.

26. A motor-operated valve diagnostic apparatus for diagnosing a motor-operated valve, the motor-operated valve comprising a valve disc for opening and closing a given passage, a worm rotatably driven by motor power, a link mechanism which opens and closes the valve disc with the rotational driving force transmitted from the worm, and a spring cartridge containing disc springs which expand or compress in response to reaction force acting on the worm in its axial direction from the link mechanism, the apparatus being characterized by comprising a worm position sensor mounted on the motor-operated valve for detecting the start of the worm axial displacement, a stress sensor attached to the link mechanism for detecting stress acting on the link mechanism, a diagnostic device or diagnostic means for diagnosing the motor-operated valve based on the preload of the spring cartridge, the preload being detected based on the stress detected by the stress sensor at the starting time of the worm displacement detected by the worm position sensor, and an output device or output means for outputting the diagnostic results and/or diagnostic data obtained by the diagnostic device or diagnostic means.

27. The motor-operated valve diagnostic apparatus as claimed in claim 26, characterized in that the aforementioned diagnostic device or diagnostic means calibrates the torque curve representing the elastic characteristics of the spring cartridge and, based on the torque curve thus calibrated, produces a diagnosis of the motor-operated valve.