WO2012087329A1

WO2012087329A1 - Corrosion detection for coated ropes or belts

Info

Publication number: WO2012087329A1
Application number: PCT/US2010/061967
Authority: WO
Inventors: Hong Yang; Xiaoyuan Chang
Original assignee: Otis Elevator Company
Priority date: 2010-12-23
Filing date: 2010-12-23
Publication date: 2012-06-28

Abstract

A system for detecting degradation of a wire in a coated rope or belt includes a reference electrode in electrical communication with the rope or belt and a probe in electrical communication with a wire of the rope or belt. An electrochemical measurement device is connected to the reference electrode and the probe and is configured to measure an electrical potential across the wire. The measured potential indicates a level of degradation of the wire. A method of detecting degradation of a wire in a coated rope or belt includes providing a probe in electrical communication with a wire of a rope or belt and providing a reference electrode in electrical communication with the wire of the rope or belt. A corrosion potential across the wire is measured via the probe and the reference electrode. A level of degradation of the wire is determined based on the measured potential.

Description

CORROSION DETECTION FOR COATED ROPES OR BELTS

BACKGROUND OF THE INVENTION

[0001] The subject matter disclosed herein relates to coated ropes or belts such as those used in elevator systems. More specifically, the subject disclosure relates detection of corrosion of coated ropes or belts for elevator suspension and/or driving.

[0002] Elevator systems utilize a lifting means, such as coated ropes or belts operably connected to an elevator car, and routed over one or more sheaves, also known as pulleys, to propel the elevator along a hoistway. Coated ropes or belts in particular typically include a plurality of steel wires at least partially within a jacket material. The plurality of wires are often arranged into one or more strands and the strands are then arranged into one or more cords. During normal elevator operation, steel wire or cord degradation is mainly caused by fretting between wires when the belts bend over the sheaves under tension.

[0003] Resistance-based inspection (RBI) is typically used to assess fretting-caused wire or cord degradation. This inspection correlates an increase in electrical resistance of the wires or cords to a strength loss of the wires or cords, and therefore the coated rope or belt.

[0004] In some environments, however, corrosion of the wires via oxidation may also be a large contributor to cord degradation. Conventional RBI systems may not have sufficient sensitivity to assess localized corrosion-caused degradation. In addition, the presence of water or moisture in the coated rope or belt, and/or in contact with one or more wires, can cause an incorrect resistance measurement or shorting resulting in a potential RBI malfunction.

BRIEF DESCRIPTION OF THE INVENTION

[0005] According to one aspect of the invention, a system for detecting degradation of a wire in a coated rope or belt includes a reference electrode in electrical communication with the coated rope or belt and a probe in electrical communication with a wire of the coated rope or belt. An electrochemical measurement device is operably connected to the reference electrode and the probe and is configured to measure a corrosion potential across the wire. The measured potential is indicative of a level of degradation of the wire.

[0006] Alternatively in this or other aspects of the invention, the electrochemical measurement device is a voltage meter. [0007] Alternatively in this or other aspects of the invention, wherein the reference electrode is in electrical communication with the coated rope or belt via an electrolyte material.

[0008] Alternatively in this or other aspects of the invention, wherein the coated rope or belt includes a plurality of wires at least partially enclosed in a jacket.

[0009] Alternatively in this or other aspects of the invention, the probe is configured to pierce the jacket and contact at least one of the plurality of wires.

[0010] Alternatively in this or other aspects of the invention, the system is operable in conjunction with a resistance based inspection system.

[0011] Alternatively in this or other aspects of the invention, the degradation is oxidation.

[0012] According to another aspect of the invention, a method of detecting degradation of a wire in a coated rope or belt includes providing a probe in electrical communication with a wire of a coated rope or belt and providing a reference electrode in electrical communication with the wire of the coated rope or belt. A corrosion potential across the wire is measured via the probe and the reference electrode. A level of degradation of the wire is determined based on the measured potential.

[0013] Alternatively in this or other aspects of the invention, the reference electrode is in electrical communication with the coated rope or belt via an electrolyte material.

[0014] Alternatively in this or other aspects of the invention, the coated rope or belt includes a plurality of wires at least partially enclosed in a jacket.

[0015] Alternatively in this or other aspects of the invention, the method includes piercing the jacket with the probe to bring the probe into contact with at least one of the plurality of wires.

[0016] Alternatively in this or other aspects of the invention, the method is operable in conjunction with a resistance based inspection system.

[0017] Alternatively in this or other aspects of the invention, the determining step determines a level of oxidation of the wire based on the measured potential.

[0018] Alternatively in this or other aspects of the invention, differences in measured potential are indicative of differences in levels of degradation.

[0019] Alternatively in this or other aspects of the invention, an increase in measured potential indicates a greater degree of degradation.

[0020] Alternatively in this or other aspects of the invention, the electrical potential is measured via a voltage meter. [0021] Alternatively in this or other aspects of the invention, the system is utilized in combination with an elevator system.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] FIG. 1 is schematic of an embodiment of a corrosion detection system;

[0023] FIG. 2 is a cross-sectional view of an embodiment of a wire for an elevator tension member;

[0024] FIG.3 is a graph illustrating corrosion potential versus level of corrosion; and [0025] FIG. 4 is a schematic view of another embodiment of a corrosion detection system.

[0026] The detailed description explains the invention, together with advantages and features, by way of examples with reference to the drawings.

DETAILED DESCRIPTION OF THE INVENTION

[0027] Shown in FIG. 1 is an embodiment of corrosion detecting system 10. The system 10 is configured to interface with a tension member for an elevator, such as a coated rope or belt 12. To avoid repetition, all instances of belt below shall refer to a rope or belt. The belt 12 includes a plurality of metallic (e.g. steel) wires 14, which in some belts 12 are grouped into cords 16. The cords 16 are at least partially enclosed in a jacket 18.

[0028] The detection system 10 utilizes an electrolyte 20, which may be a gel or solid electrolyte 20, placed along an outer surface 22 of the belt 12. A reference electrode 24 is placed in contact with the electrolyte 20. One or more probes 26 are put into contact with a cord 16 or individual wires 14 of the belt 12. The probes 26 may pass through the electrolyte 20 and pierce the jacket 18 to contact the cord 16, or may contact the cord 16 or wires 14 at an open end of the belt 12. Cords 16 or wires 14 may be contacted individually as shown in FIG. 1 , or a plurality of probes 26 may be utilized to contact some or all of the cords 16 or wires 14 simultaneously. The probes 26 and the reference electrode 24 are connected to an electrochemical measurement device, such as a voltage meter 28, which in some embodiments is a high impedance voltage meter 28, and a potential, referred to as a "corrosion potential" is measured across the cord 16 or cords 16.

[0029] As an example, the detection system 10 could be a permanent fixture of an elevator system or a temporary/portable unit. The detection system 10 could also contact the cords/wires at a free end of the belt 12, such as an unloaded portion of the belt that extends from a termination that secures the belt 12 to the elevator system (e.g. a car and/or a counterweight) or structure within a hoistway (e.g. machine bedplate or rails) or at any other suitable location.

[0030] The level of corrosion potential measured by the voltage meter 28 or other electrochemical measurement device is indicative of a level of oxidation or corrosion of the cord 16 or wires 14. For example, referring to FIG. 2, in some embodiments of belt 12, the wires 14 utilized include a steel portion 30 coated or encapsulated in a coating layer 32, of for example, a zinc material. As the coating layer 32 corrodes, a level corrosion potential is measured by the voltage meter 28. When the corrosion reaches the inner steel portion 30, the measured corrosion potential is at a level different than that measured during coating layer 32 corrosion.

[0031] Referring to FIG. 3, for a wire 14 having an inner steel portion 30 and a coating layer 32 of a zinc material, the corrosion potential measures at a baseline level 34 for wires 14 or cord 16 having no corrosion. For wires 14 or cord 16 with corrosion of the coating layer 32 the corrosion potential increases to a zinc corrosion level 36. The system 10 detects corrosion potential at a steel corrosion level 38, greater than the zinc corrosion level 36, when the steel portion 30 begins to corrode. The level of corrosion potential detected by the system 10 equates with the level of corrosion of the cord 16 or wires 14. Detecting corrosion of the cord 16 or wires via the system 10 allows for the monitoring of belt 12 degradation so that degradation can be addressed before further damage to the belt 12 or an elevator system in which the belt 12 is utilized.

[0032] While utilization of the detection system 10 is described herein as used to detect corrosion in a wire 14 having a steel portion 30 and having a coating material 32 of a zinc material, it is to be appreciated that the detection system 10 may be utilized to detect corrosion in a wire 14 of a variety of suitable materials subject to corrosion, which may be coated or uncoated. Further, in some embodiments, the coating material 32 may be metallic, while in others, the coating material 32 is nonmetallic. For embodiments having nonmetallic coating material 32, deterioration of the coating material 32 is detected by measuring parameters other than corrosion potential, for example, impedance or capacitance. As shown in FIG. 4, the detection system 10 may be used in conjunction with a resistance-based inspection (RBI) system 40 which detects degradation of the wires 14 or cord 16 by flowing a current through the wires 14 or cord 16 and comparing a measured resistance to a baseline. Since measurement of corrosion potential is performed without flowing a current through the wires 14 or cord 16, measurement of corrosion potential via the detection system 10 may be done between pulses of current flowed through the wires 14 or cord 16 via the RBI system 40 or before or after completion of the RBI operation. When measuring parameters other than corrosion potential, such as capacitance or impedance as stated above, measurement via the electrochemical measurement device may occur during current flow through the wires 14 or cord 16, allowing for measurement during RBI operation.

[0033] While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.

Claims

) WO 2012/087329 PCT/US2010/061967 CLAIMS:

1. A system for detecting degradation of a wire in a coated rope or belt comprising: a reference electrode in electrical communication with the coated rope or belt; a probe in electrical communication with a wire of the coated rope or belt; and

an electrochemical measurement device operably connected to the reference electrode and the probe and configured to measure a corrosion potential across the wire;

wherein the measured potential is indicative of a level of degradation of the wire.

2. The system of Claim 1, wherein the electrochemical measurement device is a voltage meter.

3. The system of Claim 1, wherein the reference electrode is in electrical communication with the coated rope or belt via an electrolyte material.

4. The system of Claim 1, wherein the coated rope or belt comprises a plurality of wires at least partially enclosed in a jacket.

5. The system of Claim 4, wherein the probe is configured to pierce the jacket and contact at least one of the plurality of wires.

6. The system of Claim 1 operable in conjunction with a resistance based inspection system.

7. The system of Claim 1, wherein the degradation is oxidation.

8. A method of detecting degradation of a wire in a coated rope or belt, the method comprising:

providing a probe in electrical communication with a wire of a coated rope or belt; providing a reference electrode in electrical communication with the wire of the coated rope or belt;

measuring a corrosion potential across the wire via the probe and the reference electrode; and

determining a level of degradation of the wire based on the measured potential.

9. The method of Claim 8, wherein the reference electrode is in electrical communication with the coated rope or belt via an electrolyte material. )

WO 2012/087329 PCT/US2010/061967

10. The method of Claim 8, wherein the coated rope or belt comprises a plurality of wires at least partially enclosed in a jacket.

11. The method of Claim 10, further comprising piercing the jacket with the probe to bring the probe into contact with at least one of the plurality of wires.

12. The method of Claim 8 operable in conjunction with a resistance based inspection system.

13. The method of Claim 8, wherein the determining step determines a level of oxidation of the wire based on the measured potential.

14. The method of Claim 8, wherein differences in measured potential are indicative of differences in levels of degradation.

15. The method of Claim 14, wherein an increase in measured potential indicates a greater degree of degradation.

16. The method of Claim 8, wherein the corrosion potential is measured via a voltage meter.

17. The system of Claim 1 , in combination with an elevator system.