MACHINE

TECHNICAL FIELD

The present disclosed subject matter generally relates to the field of rotating machine sensing and evaluation and, in one particular example, to a rotating machine with a wireless interface for communicating with one or more internal shaft-mounted sensors and methods of accessing such sensors.

BACKGROUND in many situations, sensing of vibration, temperature, pressure, stress or fatigue on various items of rotating equipment, such as motors, pumps, compressors, etc, is desirable and sometimes required to determine the present condition of the equipment or structure and/or its remaining useful life, in one particular application, sensors installed on the equipment/structure may be periodically accessed and data obtained from accessing such a sensor may be evaluated for purposes of determining bearing wear or failure, shaft stress, fatigue or bending, pressure boundary integrity, etc.

Conventional sensor arrangements require multiple intrusive probes mounted on various locations within the machine and a distribution system for communicating the monitored parameters. The multiple penetrations give rise to increased likelihood of pressure boundary breaches, especially in high pressure subsea environments. Certain probes, such as Eddy-current sensors, are also susceptible to temperature-induced variation and may only be employed with particular shaft materials.

The present application is directed to a wireless shaft-mounted sensor for a rotating machine and methods of accessing such a sensor that may eliminate or at least minimize some of the problems noted above.

SUMMARY

The following presents a simplified summary of the subject matter disclosed herein in order to provide a basic understanding of some aspects of the information set forth herein. This summary is not an exhaustive overview of the disclosed subject matter. It is not intended to identify key or critical elements of the disclosed subject matter or to delineate the scope of various embodiments disclosed herein. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is discussed later.

A rotating machine (200) includes a housing (205), a shaft (230) supported in the housing (205) and having a bore (235) defined therein, and a sensor module (100) positioned in the bore (235). The sensor module (100) includes one or more sensors (1 10A-1 10D), a primary communication unit (135) mounted to the housing (205), and a secondary communication unit (130) coupled to the one or more sensors (1 10A-1 10D) and mounted to the shaft to communicate wirelessly to the primary communication unit data collected by the sensors (1 1 OA- H OD).

A method includes mounting a sensor module (100) at least partially in a bore (235) defined in a shaft (230) of a rotating machine (200). The sensor module (100) includes one or more sensors (110A-1 10D), a primary communication unit (135) mounted to a housing (205) of the rotating machine (200), and a secondary communication unit (130) coupled to the one or more sensors (1 1 OA- H OD) and wirelessly connected to the primary communication unit (135). Sensor data from the at least one sensor (1 10A-1 10D) is communicated from the secondary communication unit (130) to the primary communication unit (135). A condition metric associated with the rotating machine (200) is determined based on the received sensor data.

BRIEF DESCRIPTION OF THE DRAWINGS

Certain aspects of the presently disclosed subject matter will be described with reference to the accompanying drawings, which are representative and schematic in nature and are not be considered to be limiting in any respect as it relates to the scope of the subject matter disclosed herein:

Figure 1 is a cross-sectional view of a rotating machine with one or more wireless shaft-mounted sensors, according to some embodiments disclosed herein;

Figure 2 is a diagram of a sensor insert for interfacing with the rotating machine of Figure 1 , according to some embodiments disclosed herein; Figure 3 includes a simplistic block diagram of the condition monitoring unit of Figure 1 , according to some embodiments disclosed herein; and

Figure 4 is a flow diagram of a method for determining a condition of a rotating machine, according to some embodiments disclosed herein, While the subject matter disclosed herein is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the disclosed subject matter to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosed subject matter as defined by the appended claims.

DESCRIPTION OF EMBODIMENTS

Various illustrative embodiments of the disclosed subject matter are described below. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure.

The present subject matter will now be described with reference to the attached figures. Various structures, systems and devices are schematically depicted in the drawings for purposes of explanation only and so as to not obscure the present disclosure with details that are well known to those skilled in the art. Nevertheless, the attached drawings are included to describe and explain illustrative examples of the present disclosure. The words and phrases used herein should be understood and interpreted to have a meaning consistent with the understanding of those words and phrases by those skilled in the relevant art. No special definition of a term or phrase, i.e., a definition that is different from the ordinary and customary meaning as understood by those skilled in the art, is intended to be implied by consistent usage of the term or phrase herein. To the extent that a term or phrase is intended to have a special meaning, i.e., a meaning other than that understood by skilled artisans, such a special definition will be expressly set forth in the specification in a definitional manner that directly and unequivocally provides the special definition for the term or phrase. One illustrative example of a novel sensor module 100 will be described with reference to the attached drawings. With reference to Figures 1 and 2, the sensor module 100 is mounted in a rotating machine 200 in one illustrative embodiment. The sensor module 100 is illustrated in Figure 2, and the rotating machine 200 in which the sensor module 100 is mounted is illustrated in Figure 1. Figure 1 includes a simplistic illustration of the rotating machine 200. The rotating machine 200 may be a motor, a pump, a compressor, a generator, etc. Elements such as a motor stator, pump impellor, etc. are omitted from Figure 1 for ease of illustration.

Referring to Figure 2, the sensor module 100 includes a body 105 with one or more sensors 11 OA- HOD. In some embodiments, the sensors may include temperature sensors 11 OA, displacement sensors 110B, a pressure sensor HOC, or some other sensor HOD (MiSC) useful for shaft or bearing condition monitoring. The displacement sensors HOB may be of various types, such as vibration sensors, shock sensors (e.g. , accelerometers), stress sensors (e.g., piezoelectric), etc. The sensors 1 1 OA-H OD may comprise, for instance, microelectromechanical system (MEMS)-based sensors that provide combined sensor functionality (e.g., accelerometer, gyroscope, magnetometer, etc.) in a single sensor package. The sensors 11 OA- HOD may be arranged in various positions and configurations along the length of the body 105. The body 105 may be covered with an outer shell 120 (e.g. , tubular member, wrap, coating, etc.) The sensors 110A-110D may be coupled to a bus 125 (e.g., a serial bus), which communicates with a secondary communication unit 130. A primary communication unit 135 mounted to the rotating machine 200 communicates with the secondary communication unit 130 via a wireless link 140. The primary communication unit 135 may provide power to the secondary communication unit 130 via the wireless link and the communication units 130, 135 may exchange control and data signals. The secondary communication unit 130 may distribute power to the sensors Π 0A-H0D via the bus 125. Referring to Figure 1, the rotating machine 200 includes a housing 205 in which a penetration 210 is defined. The primary communication unit 135 may be mounted in the penetration 210, and a flange 215 may be provided to seal the penetration 210 and to allow a connection 220 to be made between the primary communication unit 135 and a condition monitoring unit 225. In some embodiments, the condition monitoring unit 225 is housed remotely from the rotating machine 200 (e.g. , in a surface facility when the rotating machine 200 is installed in a subsea environment). In other embodiments, the condition monitoring unit 225 may be positioned proximate the rotating machine 200 outside the pressure boundary of the housing 205. Although the connection 220 is illustrated as being a hardwired connection, wireless connections or a combination of hardwired and wireless connections may also be provided. The rotating machine 200 also includes a shaft 230 into which a bore 235 has been provided to receive the sensor module 100. Bearings 240 are provided for supporting the shaft 230 within the housing 205,

Figures 1 and 2 simplistic-ally depict an illustrative example of where the sensors 110A~ HOD in the sensor module 100 may be employed. In the example depicted, the temperature sensors 11 OA may be mounted proximate the bearings 240 to provide an indication of bearing failures. The displacement sensors HOB may be distributed along the length of the shaft 230 to measure shaft stress, bending, fatigue, etc. The displacement sensors HOB mounted proximate the bearings 240 may also provide indication of bearing failure. In one embodiment, the pressure sensor H OC is mounted at an end of the bore 235 to seal the bore 235 and to provide readings of the pressure within the housing 205 to assess cooling system integrity. Other pressure sensors HOC may be provided at different locations.

Figure 3 includes a simplistic block diagram of the condition monitoring unit 225. The condition monitoring unit 225, includes, among other things, a processor 300, a memory 305, a power supply 310 (e.g. , battery, solar unit, hardwire connection, etc.). The memory 305 may be a volatile memory (e.g. , DRAM, SRAM) or a non-volatile memory (e.g. , ROM, flash memory, hard disk, etc.). The processor 300 may execute instructions stored in the memory 305 and store information in the memory 305, such as the results of the executed instructions. The processor 300 may implement a condition monitoring model 315 that employs the outputs of the sensors 11 OA- HOD to determine a condition metric for the rotating machine 200 and perform portions of a method 400 shown in Figure 4 and discussed below.

Figure 4 is a flow diagram of a method 400 for determining a condition of a rotating machine 200, according to some embodiments disclosed herein. In method block 405, the sensor module 100 is mounted in the shaft 225 of the rotating machine 200. in method block 41 0, data from the sensor module 100 is received using a wireless shaft mounted communication unit 130, 135. In method block 415, a condition metric associated with the rotating machine 200 is generated based o the received sensor data. There are various techniques that the condition monitoring unit 225 may employ to determine a condition metric for the rotating machine 200, In some embodiments, the condition monitoring unit 225 may employ the outputs of the sensors 110 A- HOD in conjunction with the condition monitoring model 315 to identify conditions such as bearing wear, bearing failure, shaft wear, shaft bending, cooling system degradation, pressure boundary failure, etc. Machine learning algorithms may be employed to re-learn, optimize and adapt to changing process and environmental conditions to build new models in the field. In some embodime ts, the condition monitoring model may include a Remaining-Useful-Life (RUL) component that employs the measured and calculated parameters to estimate a RUL metric for the rotating machi e 200. The RUL metric may be employed to schedule replacement of or maintenance for the rotating machine 200.

One type of model that may be used to determine a condition metric is a recursive principal components analysis (RPCA) model. Condition metrics are calculated by comparing data for all parameters from the sensors and derived parameters generated based on the sensor readings to a model built from known-good data. The model may employ a hierarchy structure where parameters are grouped into related nodes. The sensor nodes are combined to generate higher level nodes. For example, data related to bearing health (e.g. , vibration, temperature, etc.) may be grouped into a higher level node, and nodes associated with the other condition parameters (e.g. , related to shaft bending) may be further grouped into yet another higher node, leading up to an overall node that reflects the overall condition or RUL of the rotating machine 200. The nodes may be weighted based on perceived criticality in the system. Hence, a deviation detected on a component deemed important may be elevated based on the assigned weighting. For an RPCA technique, as is well known in the art, a metric may be calculated for every node in the hierarchy, and is a positive number that quantitatively measures how far the value of that node is within or outside 2.8-σ of the expected distribution. An overall combined index may be used to represent the overall maintenance condition of the rotating machine 200. The condition monitoring model 315 may also employ data other than the data from the sensors 11 O -H OD in determining the intermediate or overall condition metrics. For example, real time production data and/or historical data may also he employed. The historical data may be employed to identify trends with the rotating machine 200. in some embodiments, certain aspects of the techniques described above may be implemented by one or more processors of a processing system executing software. The method 400 described herein may be implemented by executing software o a computing device, such as the condition monitoring unit 225 of Figure 3, however, such methods are not abstract in that they improve the operation of the rotating machine 200. Prior to execution, the software instructions may be transferred from a non-transitory computer readable storage medium to a memory, such as the memory 305 of Figure 3. The software may include one or more sets of executable instructions stored or otherwise tangibly embodied on a non-transitory computer readable storage medium. The software can include the instructions and certain data that, when executed by one or more processors, manipulate the one or more processors to perform one or more aspects of the techniques described above. The non-transitory computer readable storage medium can include, for example, a magnetic or optical disk storage device, solid state storage devices such as Flash memory, a cache, random access memory (RAM) or other non-volatile memory device or devices, and the like. The executable instructions stored on the non-transitory computer readable storage medium may be in source code, assembly language code, object code, or other instruction format that is interpreted or otherwise executable by one or more processors.

A computer readable storage medium may include any storage medium, or combination of storage media, accessible by a computer system during use to provide instructions and/or data to the computer system. Such storage media can include, but is not limited to, optical media (e.g. , compact disc (CD), digital versatile disc (DVD), Blu-Ray disc), magnetic media (e.g. , floppy disc, magnetic tape or magnetic hard drive), volatile memory (e.g., random access memory (RAM) or cache), non-volatile memory (e.g., readonly memory (ROM) or Flash memory), or MEMS -based storage media. The computer readable storage medium may be embedded in the computing system (e.g. , system RAM or ROM), fixedly attached to the computing system (e.g. , a magnetic hard drive), removably attached to the computing system (e.g. , an optical disc or Universal Serial Bus (USB)-based Flash memory), or coupled to the computer system via a wired or wireless network (e.g. , network accessible storage (NAS)). As will be appreciated by those skilled in the art after a complete reading of the present application, the novel sensor systems and methods disclosed herein can be employed to monitor accumulated fatigue on equipment/structures even when the equipment/structures are located or positioned in environments that make access to equipment/structures difficult if not impossible for a human inspector. That is, the methods, devices and systems disclosed herein may be employed to periodically inspect items, such as pressure vessels (and the like), to make sure that stressed areas (the areas of interest) of the vessel are not exhibiting any fatigue cracks that could compromise the future integrity of the pressure vessel. As noted in the background section of this application, in the case where a pressure vessel was in an environment where it could not be inspected for fatigue cracks, the assumed safety factor used in designing the pressure vessel was raised with the net result being that the pressure vessel was taken out of service much sooner than its predicted service life. By using at least some aspects of at least portions of the presently disclosed subject matter, such vessels may be inspected periodically and the owners of such equipment do not have to assume an increased safety factor for such equipment with the net result being that the pressure vessel does not have to be taken out of service prematurely, i.e., the vessel may be used for its entire predicted service life. Thus, the difference in safety factor on allowable design life can be of huge commercial advantage without changing the equipment design, just by adding a monitoring feature to the equipment, such as using the embodied sensors, systems and methods disclosed herein.

The particular embodiments disclosed above are illustrative only, as the disclosed subject matter may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. For example, the process steps set forth above may be performed in a different order. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the claimed subject matter. Note that the use of terms, such as "first," "second," "third" or "fourth" to describe various processes or structures in this specification and in the attached claims is only used as a shorthand reference to such steps/structures and does not necessarily imply that such steps/structures are performed/formed in that ordered sequence. Of course, depending upon the exact claim language, an ordered sequence of such processes may or may not be required. Accordingly, the protection sought herein is as set forth in the claims below.