Patent Application
20120326730
The present application relates generally to power systems and, more particularly, to a sensor assembly and a microwave emitter for use in a sensor assembly.
Known machines may exhibit vibrations and/or other abnormal behavior during operation. One or more sensors may be used to measure and/or monitor such behavior and to determine, for example, an amount of vibration exhibited in a machine drive shaft, a rotational speed of the machine drive shaft, and/or any other operational characteristic of an operating machine or motor. Often, such sensors are coupled to a machine monitoring system that includes a plurality of monitors. The monitoring system receives signals from one or more sensors, performs at least one processing step on the signals, and transmits the modified signals to a diagnostic platform that displays the measurements to a user.
At least some known machines use eddy current sensors to measure the vibrations in and/or a position of a machine component. However, the use of known eddy current sensors may be limited because a detection range of such sensors is only about half of a diameter of the eddy current sensing element. Other known machines use optical sensors to measure a vibration and/or a position of a machine component. However, known optical sensors may become fouled by contaminants and provide inaccurate measurements, and as such, may be unsuitable for industrial environments. Further, known optical sensors may not be suitable for detecting a vibration and/or a position of a machine component through a liquid medium and/or a medium that includes particulates.
In one embodiment, a microwave probe for use in a microwave sensor assembly is provided that includes an emitter body and an emitter coupled to the emitter body. The emitter includes a first portion, a second portion, and a connecting portion coupling the first portion to the second portion. The first portion and the second portion generate an electromagnetic field when at least one microwave signal is received, and a loading is induced to the emitter when an object is positioned within the electromagnetic field.
In another embodiment, a microwave sensor assembly is provided that includes an emitter body and an emitter coupled to the emitter body. The emitter includes a first portion, a second portion, and a connecting portion coupling the first portion to the second portion. The first portion and the second portion generate an electromagnetic field when at least one microwave signal is received. The microwave sensor assembly also includes a signal processing device coupled to the emitter for transmitting at least one microwave signal to the emitter and for calculating a proximity measurement based on a signal received from the emitter.
In yet another embodiment, a method for measuring a proximity of a machine component relative to an emitter is provided. The method includes transmitting at least one microwave signal to the emitter that includes a first portion, a second portion, and a connecting portion coupling the first portion to the second portion. The first portion and the second portion generate an electromagnetic field when at least one microwave signal is received. The method also includes generating an electromagnetic field from the at least one microwave signal, generating a loading signal representative of a disruption of the electromagnetic field, and calculating the proximity of the machine component to the emitter based on the loading signal.
In the exemplary embodiment, drive shaft 104 is at least partially supported by one or more bearings (not shown) housed within machine 102 and/or within load 106. Alternatively or additionally, the bearings may be housed within a separate support structure 108, such as a gearbox, or within any other structure or component that enables power system 100 to function as described herein.
In the exemplary embodiment, power system 100 includes at least one sensor assembly 110 that measures and/or monitors at least one operating condition of machine 102, of drive shaft 104, of load 106, and/or of any other component of power system 100 that enables system 100 to function as described herein. More specifically, in the exemplary embodiment, sensor assembly 110 is a proximity sensor assembly 110 positioned in close proximity to drive shaft 104 for measuring and/or monitoring a distance (not shown in
During operation, in the exemplary embodiment, the operation of machine 102 may cause one or more components of power system 100, such as drive shaft 104, to change position with respect to at least one sensor assembly 110. For example, vibrations may be induced to the components and/or the components may expand or contract as the operating temperature within power system 100 changes. In the exemplary embodiment, sensor assemblies 110 measure and/or monitor the proximity and/or the position of the components relative to each sensor assembly 110 and transmit a signal representative of the measured proximity and/or position of the components (hereinafter referred to as a “proximity measurement signal”) to diagnostic system 112 for processing and/or analysis.
In the exemplary embodiment, signal processing device 200 includes a directional coupling device 210 coupled to a transmission power detector 212, to a reception power detector 214, and to a signal conditioning device 216. In the exemplary embodiment, signal conditioning device 216 includes a signal generator 218, a subtractor 220, and a linearizer 222. Emitter 206 emits an electromagnetic field 224 when a microwave signal is transmitted through emitter 206.
During operation, in the exemplary embodiment, signal generator 218 generates at least one electrical signal having a microwave frequency (hereinafter referred to as a “microwave signal”) that is equal or approximately equal to the resonant frequency of emitter 206. Signal generator 218 transmits the microwave signal to directional coupling device 210. Directional coupling device 210 separates the microwave signal and transmits or directs at least a portion of the microwave signal to transmission power detector 212 and transmits or directs the remaining portion of the microwave signal to emitter 206. As the microwave signal is transmitted through emitter 206, electromagnetic field 224 is emitted from emitter 206 and out of probe housing 208. If an object, such as a drive shaft 104 or another component of machine 102 (shown in
In the exemplary embodiment, reception power detector 214 determines an amount of power based on and/or contained within the detuned loading signal and transmits a signal representative of the detuned loading signal power to signal conditioning device 216. Transmission power detector 212 determines an amount of power based on and/or contained within the microwave signal and transmits a signal representative of the microwave signal power to signal conditioning device 216. In the exemplary embodiment, subtractor 220 receives the microwave signal power and the detuned loading signal power, and calculates a difference between the microwave signal power and the detuned loading signal power. Subtractor 220 transmits a signal representative of the calculated difference (hereinafter referred to as a “power difference signal”) to linearizer 222. In the exemplary embodiment, an amplitude of the power difference signal is proportional, such as inversely or exponentially proportional, to a distance 226 defined between the object, such as drive shaft 104, within electromagnetic field 224 and probe 202 and/or emitter 206 (i.e., distance 226 is known as the object proximity). Depending on the characteristics of emitter 206, such as, for example, the geometry of emitter 206, the amplitude of the power difference signal may at least partially exhibit a non-linear relationship with respect to the object proximity.
In the exemplary embodiment, linearizer 222 transforms the power difference signal into a voltage output signal (i.e., the “proximity measurement signal”) that exhibits a substantially linear relationship between the object proximity and the amplitude of the proximity measurement signal. Further, in the exemplary embodiment, linearizer 222 transmits the proximity measurement signal to diagnostic system 112 (shown in
In the exemplary embodiment, emitter body 300 includes a front surface 302 and an opposing rear surface 304. Emitter 206 is coupled to, and/or is formed integrally with, front surface 302. More specifically, in the exemplary embodiment, emitter body 300 is a substantially planar printed circuit board, and emitter 206 includes one or more traces or conductors (not shown in
In the exemplary embodiment, data conduit 204 includes an inner conductor 306 and an outer conductor 308 that substantially encloses inner conductor 306 such that conductors 306 and 308 are coaxial. Data conduit 204, in the exemplary embodiment, is a semi-rigid cable 204 that couples emitter 206 to signal processing device 200 (shown in
During operation, at least one microwave signal is transmitted to emitter 206 through inner conductor 306 and outer conductor 308. As the microwave signal is transmitted through emitter 206, an electromagnetic field 224 (shown in
In the exemplary embodiment, emitter 400 includes a first portion 406, a second portion 408, and a connecting portion 410 that couples first portion 406 to second portion 408. Emitter 400 also includes an inner portion 412 that is substantially enclosed by first portion 406, second portion 408, and connecting portion 410. In the exemplary embodiment, first portion 406, second portion 408, connecting portion 410, and inner portion 412 are substantially coplanar with front surface 302 such that emitter 400 does not extend a substantial distance axially outward from front surface 302. Alternatively, emitter 400 and/or emitter body 300 may include any number of emitter portions and/or may be any shape that enables microwave sensor assembly 110 to function as described herein.
First portion 406, in the exemplary embodiment, includes a plurality of substantially arc-shaped segments 414 that are concentrically aligned with each other about center 402. Alternatively, segments 414 may have any other shape or configuration that enables emitter 400 to function as described herein. In the exemplary embodiment, segments 414 include a radially outermost segment 416 and a radially innermost segment 418. In the exemplary embodiment, segments 414 also include at least one middle segment 420 coupled to radially outermost segment 416 and/or to radially innermost segment 418. Each segment 414 is radially aligned with center 402 and is coupled to a neighboring segment 414 by at least one segment end 422. Each segment end 422 is alternately spaced with respect to each other segment end 422. More specifically, a first radius 424 extends through center 402 along a first edge 426 of first portion 406, and a second radius 428 extends through center 402 along a second edge 430 of first portion 406. In the exemplary embodiment, segment end 422 at a radially inner end 432 of first portion 406 is positioned substantially against first radius 424, and the next radially outer segment end 422 is positioned substantially against second radius 428. Subsequent radially outer segment ends 422 are positioned alternatingly against first radius 424 and second radius 428.
In the exemplary embodiment, radially outermost segment 416 has a width 434 that is greater than a width 436 of each other segment 414. In addition, segments 414 increase in length as segments 414 are spaced at an increasing radial distance from center 402. More specifically, radially innermost segment 418 has an arc length 438 that is smaller than an arc length 438 of middle segment 420, and middle segment arc length 438 is smaller than an arc length 438 of radially outermost segment 416.
Second portion 408, in the exemplary embodiment, is substantially similar to first portion 406. Accordingly, segments 414 and segment ends 422 of second portion 408 are substantially similar to segments 414 and segment ends 422 of first portion 406.
It should be recognized that modifications may be made to the shape and/or configuration of first portion 406 and/or second portion 408. For example, first portion 406 and/or second portion 408 may include any number of segments 414 and/or segment ends 422. Further, first radius 424 and second radius 428 divide front surface 302 into a first quadrant 440, a second quadrant 442, a third quadrant 444, and a fourth quadrant 446. While first portion 406 is illustrated as being positioned within first quadrant 440, first portion 406 may alternatively extend into second quadrant 442, third quadrant 444, and/or fourth quadrant 446. In addition, while second portion 408 is illustrated as being positioned within fourth quadrant 446, second portion 408 may alternatively extend into first quadrant 440, second quadrant 442, and/or third quadrant 444.
In the exemplary embodiment, connecting portion 410 is substantially circular and/or substantially arc-shaped, and is positioned about center 402. Connecting portion 410 electrically couples radially inner end 432 of first portion 406 to radially inner end 432 of second portion 408.
Inner portion 412, in the exemplary embodiment, is substantially circular and is positioned about center 402. Inner portion 412 is coupled to inner conductor 306 of data conduit 204 (both shown in
During operation, at least one microwave signal is transmitted to emitter 400 through data conduit 204. The microwave signal is transmitted to inner portion 412 by inner conductor 306. As the microwave signal is transmitted through inner portion 412, a capacitive coupling occurs between inner portion 412 and first portion 406, second portion 408, and connecting portion 410. The capacitive coupling across gap 448 induces a current through first portion 406, second portion 408, and connecting portion 410 such that an electromagnetic field 224 (shown in
In the exemplary embodiment, emitter 500 includes a first portion 506, a second portion 508, and a connecting portion 510 that couples first portion 506 to second portion 508. In the exemplary embodiment, first portion 506, second portion 508, and connecting portion 510 are substantially coplanar with front surface 302 such that emitter 500 does not extend a substantial distance axially outward from front surface 302. Alternatively, emitter 500 and/or emitter body 300 may include any number of emitter portions and/or may be any shape that enables microwave sensor assembly 110 to function as described herein.
First portion 506 includes a radially inner end 512 and a radially outer end 514. First portion 506 also includes a plurality of radially spaced, substantially circular segments 516 that extend in a substantially spiral shape in a first, or clockwise, direction from radially inner end 512 to radially outer end 514. Second portion 508 includes a radially inner end 518 and a radially outer end 520. Second portion 508 also includes a plurality of radially spaced, substantially circular segments 522 that extend in a substantially spiral shape in a second direction different from the first direction (i.e., a counter-clockwise direction) from radially inner end 518 to radially outer end 520.
In the exemplary embodiment, radially inner end 512 of first portion 506 is coupled to inner conductor 306 of data conduit 204 (both shown in
Connecting portion 510, in the exemplary embodiment, is substantially linear. Connecting portion 510 electrically couples radially outer end 514 of first portion 506 to radially outer end 520 of second portion 508. In addition, connecting portion 510 separates first portion 506 from second portion 508 such that a gap 524 is defined between first portion 506 and second portion 508.
In an alternative embodiment, segments 522 of second portion 508 extend in a substantially spiral shape in the first direction (i.e., the clockwise direction) from radially inner end 518 to radially outer end 520. In such an embodiment, connecting portion 510 extends substantially diagonally across front surface 302 (with respect to a centerline (not shown) bisecting first portion 506 and second portion 508) to couple radially outer end 514 of first portion 506 to radially outer end 520 of second portion 508.
During operation, at least one microwave signal is transmitted to emitter 500 by data conduit 204. The microwave signal is transmitted to radially inner end 512 of first portion 506 by inner conductor 306. The microwave signal is transmitted through first portion 506 in the clockwise direction, through connecting portion 510, and through second portion 508 in the clockwise direction. As the microwave signal is transmitted through emitter 500, an electromagnetic field 224 (shown in
In the exemplary embodiment, emitter 600 includes a first portion 606, a second portion 608, and a connecting portion 610 that couples first portion 606 to second portion 608. In the exemplary embodiment, first portion 606, second portion 608, and connecting portion 610 are substantially coplanar with front surface 302 such that emitter 600 does not extend a substantial distance axially outward from front surface 302. Alternatively, emitter 600 and/or emitter body 300 may include any number of emitter portions and/or may be any shape that enables microwave sensor assembly 110 to function as described herein.
First portion 606 includes a first end 612 and a second end 614. First portion 606 extends in a substantially circular shape in a first, or counter-clockwise, direction from first end 612 to second end 614 to form a first loop. Second portion 608 includes a first end 616 and a second end 618. Second portion 608 extends in a substantially circular shape in a second direction different from the first direction (i.e., a clockwise direction) from first end 616 to second end 618 to form a second loop. Further, a diameter 620 of first portion 606 is different than (e.g., is greater than) a diameter 622 of second portion 608.
In the exemplary embodiment, first end 612 of first portion 606 is coupled to inner conductor 306 of data conduit 204 (both shown in
Connecting portion 610, in the exemplary embodiment, is substantially linear. Connecting portion 610 electrically couples second end 614 of first portion 606 to first end 616 of second portion 608.
During operation, at least one microwave signal is transmitted to emitter 600 by data conduit 204. The microwave signal is transmitted to first end 612 of first portion 606 by inner conductor 306. The microwave signal is transmitted through first portion 606 in the counter-clockwise direction, through connecting portion 610, and through second portion 608 in the clockwise direction. As the microwave signal is transmitted through emitter 600, an electromagnetic field 224 (shown in
Emitter 700 has a similar shape as emitter 600 except that emitter 700 includes a first portion 702 and a second portion 704 that each includes a plurality of substantially linear segments 706. Linear segments 706 of first portion 702 form a substantially polygonal loop that has a first diameter 708. Linear segments 706 of second portion 704 form a substantially polygonal loop that has a second diameter 710 that is different from first diameter 708. Further, linear segments 706 of first portion 702 and of second portion 704 facilitate emitting additional radiation as compared to emitter 600. In addition, first portion 702 extends in a substantially circular shape in a first, or clockwise, direction from first end 612 to second end 614 to form a loop with linear segments 706. Second portion 704 extends in a substantially circular shape in a second direction different from the first direction (i.e., a counter-clockwise direction) from first end 616 to second end 618 to form a loop with linear segments 706. In other respects, emitter 700 functions substantially similar to emitter 600.
The above-described embodiments provide an efficient and cost-effective sensor assembly for use in measuring the proximity of a machine component. The sensor assembly energizes an emitter with a microwave signal. The emitter includes a first portion and a second portion that are coupled together by a connecting portion. When an object, such as a machine component, is positioned within the field, a loading is induced to the emitter due to a disruption of the field. The sensor assembly calculates a proximity of the object to the emitter based on the loading induced to the emitter. The shapes and/or configurations of the microwave emitters described herein facilitate providing a frequency stable electromagnetic field for use in measuring the proximity between the object and the emitter.
Exemplary embodiments of a sensor assembly and a microwave emitter are described above in detail. The sensor assembly and emitter are not limited to the specific embodiments described herein, but rather, components of the sensor assembly and/or the emitter may be utilized independently and separately from other components and/or steps described herein. For example, the emitter may also be used in combination with other measuring systems and methods, and is not limited to practice with only the sensor assembly or the power system as described herein. Rather, the exemplary embodiment can be implemented and utilized in connection with many other measurement and/or monitoring applications.
Although specific features of various embodiments of the invention may be shown in some drawings and not in others, this is for convenience only. In accordance with the principles of the invention, any feature of a drawing may be referenced and/or claimed in combination with any feature of any other drawing.
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.
