Abstract:
Embodiments of the invention relate generally to the detection of anomalous or aberrant movement of a reciprocating element in a reciprocating device and, more particularly, to the analysis of one or more components of a vibration signal produced by such anomalous or aberrant movement of the reciprocating element. One embodiment of the invention provides a system for identifying an anomalous movement of a reciprocating element in a reciprocating device, the system comprising: at least one sensing device for sensing a vibration signal of the reciprocating element; a processing apparatus for separating the vibration signal into a first component having a first frequency range and a second component having a second frequency range different than the first frequency range; and an analysis device for analyzing, displaying, or both, at least one of the first and the second components of the vibration signal.

Description:
BACKGROUND OF THE INVENTION 
     Anomalous or aberrant movement of a reciprocating element in a reciprocating device poses a number of potential problems, ranging from decreased efficiency of the device to catastrophic failure of the device, with the potential for attendant harm to both people and property. While such anomalous or aberrant movement is known to produce vibratory signals, use of such signals to diagnose the cause, type, or extent of the anomalous or aberrant movement has, to date, been largely unsuccessful. 
     BRIEF DESCRIPTION OF THE INVENTION 
     One embodiment of the invention provides a system for identifying an anomalous movement of a reciprocating element in a reciprocating device, the system comprising: at least one sensing device for sensing a vibration signal of the reciprocating element; a processing apparatus for separating the vibration signal into a first component having a first frequency range and a second component having a second frequency range different than the first frequency range; and an analysis device for analyzing, displaying, or both, at least one of the first and the second components of the vibration signal. 
     Another embodiment of the invention provides a system for identifying an anomalous movement of a reciprocating element in a reciprocating device, the system comprising: a first sensing device for sensing a first component of a vibration signal of the reciprocating element, the first component having a first frequency range; a second sensing device for sensing a second component of the vibration signal of the reciprocating element, the second component having a second frequency range different than the first frequency range; and an analysis device for analyzing, displaying, or both, at least one of the first and the second components of the vibration signal. 
     Yet another embodiment of the invention provides a method of identifying an anomalous movement of a reciprocating element in a reciprocating device, the method comprising: sensing a vibration signal of the reciprocating element; separating the vibration signal into a first component having a first frequency range and a second component having a second frequency range different than the first frequency range; and analyzing, displaying, or both, at least one of the first and the second components of the vibration signal to identify an anomalous movement of the reciprocating element. 
     Still another embodiment of the invention provides a method of identifying an anomalous movement of a reciprocating element in a reciprocating device, the method comprising: sensing a first component of a vibration signal of the reciprocating element, the first component having a first frequency range; sensing a second component of the vibration signal of the reciprocating element, the second component having a second frequency range different than the first frequency range; and analyzing, displaying, or both, at least one of the first and the second components of the vibration signal to identify an anomalous movement of the reciprocating element. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features of this invention will be more readily understood from the following detailed description of the various aspects of the invention taken in conjunction with the accompanying drawings that depict various embodiments of the invention, in which: 
         FIG. 1  shows a cross-sectional side view of a system according to one embodiment of the invention in conjunction with a reciprocating device; 
         FIGS. 2-5  show cross-sectional views of reciprocating elements in conjunction with various components of systems according to embodiments of the invention; 
         FIGS. 6-7  show detailed cross-sectional views of a reciprocating device in conjunction with various components of systems according to embodiments of the invention; 
         FIGS. 8-9  show graphical representations of an illustrative analysis of different components of a vibration signal produced by a reciprocating element; and 
         FIG. 10  shows a flow diagram of a method according to an embodiment of the invention. 
     
    
    
     It is noted that the drawings of the invention are not to scale. The drawings are intended to depict only typical aspects of the invention, and therefore should not be considered as limiting the scope of the invention. In the drawings, like numbering represents like elements between the drawings. 
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows a cross-sectional side view of a reciprocating device  100  having a reciprocating element  110 , non-reciprocating elements  102 ,  104 , and a rod  112  or similar apparatus for moving the reciprocating element  110  along path A. The reciprocating device  100  may be any device having a reciprocating element. Such devices include, for example, engines, pumps, and compressors, although other devices having a reciprocating element will be known to one skilled in the art and are within the scope of devices subject to embodiments of the present invention. 
     As can be seen, the reciprocating element  110  assumes a distal position  110 ′ when fully displaced along path A by the rod  112 . It should be noted that while the non-reciprocating elements  102 ,  104  are shown and labeled as separate elements in the cross-sectional side view of  FIG. 1 , these may constitute a single non-reciprocating element through which the reciprocating element  110  passes. 
     In moving along path A, the reciprocating element  110  may produce a vibration signal  120 . That is, anomalous or aberrant movement of the reciprocating element  110  may produce a measurable vibratory signal with respect to the non-reciprocating elements  102 ,  104  or some other non-reciprocating or fixed position. Often, such anomalous or aberrant movement occurs along one or more axes oriented substantially perpendicular to a longitudinal axis of the reciprocating element  110 . As used herein, the terms “anomalous” and “aberrant” are meant to be interchangeable and to refer to movement of a reciprocating element to a degree, in a direction, or of a kind that results in suboptimal performance or efficiency of the device of which it is a part. In some cases, such movement is outside the intended operational parameters of the reciprocating element and which may result in decreased efficiency and/or damage to the reciprocating element, the reciprocating device of which it is a part, or any other device, apparatus, or system with which it is associated. 
     Still referring to  FIG. 1 , a system  700  according to one embodiment of the invention is shown, the system comprising a displacement sensor  200 , a processing apparatus  300 , and an analysis device  400 . The displacement sensor  200  senses  202  the vibration signal  120  produced by the reciprocating element  110 . In most, if not all cases, the vibration signal  120  will be a multi-frequency vibration signal  210 . That is, the vibration signal  120  produced by the reciprocating element  110  contains a plurality of vibration signals, at least two of which have different frequencies. 
     The processing apparatus  300  splits the vibration signal  120  into a plurality of components  312 ,  314 , at least two of which have different frequency ranges. For example, a first component  312  may include “low” frequency vibrations (e.g., those vibrations below a particular frequency) and a second component  314  may include “high” frequency vibrations (e.g., those vibrations above a particular frequency). It should be understood, however, that “low” and “high,” as used in this example, are relative designations merely intended to distinguish the frequency ranges of the first component  312  and the second component  314 . In other embodiments, the frequency ranges of the components may be defined as being between two specific frequencies. In still other embodiments, the processing apparatus  300  may split the vibration signal  120  into more than two components, each having a different frequency range. In some embodiments of the invention, the frequency ranges of each component do not overlap. 
     Similarly, it should be understood that less than the entire duration of the sensed vibration signal  120  may be delivered to the processing apparatus  300  (or, as will be described more fully below, subject to analysis using the analysis device  400 ). That is, the vibration signal  120  may be sensed  202  over a particular period while the first  312  and/or second component  314  processed and/or analyzed is representative of a briefer period. Likewise, the periods reflected by the first  312  and/or second component  314  may be representative of different periods. 
     The processing apparatus  300  may include any number of known or later-developed apparatuses, as will be recognized by one skilled in the art. Such apparatuses include, for example, high-pass filters, low-pass filters, and bandwidth filters. In some embodiments, the processing apparatus  300  may employ heuristic or non-deterministic methods (e.g., wavelets or neural networks) to separate a vibration signal by frequency. As used herein, the processing apparatus  300  may be any apparatus capable of splitting a vibration signal into components based on vibration frequency. 
     The analysis device  400  permits a user to separately analyze the first and second components  312 ,  314  of the vibration signal or performs such analysis itself. Accordingly, the analysis device  400  may include, for example, a printing device for producing a representation of one or more components (e.g., a printer, plotting device, etc.), an electronic display (e.g., an oscilloscope, computer monitor, etc.), or a computing device or plurality of computing devices having hardware, software, or both, for analyzing a vibration signal. Other devices useful in analyzing one or more components of the vibration signal will be known to one skilled in the art and are intended to be encompassed within the term “analysis device.” 
     Referring now to  FIGS. 2 and 3 , a facing cross-sectional view of a reciprocating element  110  is shown. In the embodiment of  FIG. 2 , a displacement sensor  200  is oriented substantially along the Y-axis of the reciprocating element  110  and senses anomalous or aberrant movement of the reciprocating element  110  along both the Y-axis (i.e., along path B) and the X-axis (i.e., along path C). 
     In the embodiment of  FIG. 3 , two displacement sensors  200 ,  220  are employed, a first displacement sensor  200  being oriented substantially along the Y-axis of the reciprocating element  110  and a second displacement sensor being oriented substantially along the X-axis of the reciprocating element  110 . Here, the first displacement sensor  200  senses anomalous or aberrant movement of the reciprocating element  110  along the Y-axis (i.e., along path B) and the second displacement sensor  220  senses anomalous or aberrant movement of the reciprocating element  110  along the X-axis (i.e., along path C). In the embodiment of  FIG. 3 , each displacement sensor  200 ,  220  may sense a vibration signal that is then separated into two or more components. 
     Alternative embodiments of the invention are shown in  FIGS. 4 and 5 . In the embodiment of  FIG. 4 , a system  800  having a pair of displacement sensors  200 ,  210  is employed, each displacement sensor being oriented substantially along the Y-axis of the reciprocating element  110 , but sensing separate components of the vibration signal. Here, a first displacement sensor  200  senses a first component  212  and a second displacement sensor  210  senses a second component  214 , the second component having a higher frequency range than the first component. In such an embodiment, the first and second components  212 ,  214  need not be further separated into constituent components and may, instead, be fed directly to the analysis device  400 . In other embodiments, it may be desirable to further separate one or more sensed components. In such embodiments, as described above, a processing apparatus ( 300  in  FIG. 1 ) may be employed to separate one or more components into constituent components. 
     In the embodiment of  FIG. 5 , a system  802  also having a first displacement sensor  200  and second displacement sensor  220  is employed, but here the second displacement sensor  220  is oriented substantially along the X-axis of the reciprocating element. As described above, in the embodiment of  FIG. 5 , the first component  212  and second component  214  need not be further separated and is instead fed directly to the analysis device  400 . In other embodiments, either or both components may be further separated into constituent components using a processing apparatus. 
     In  FIG. 6 , a detailed view of an embodiment of the invention similar to the embodiments of  FIGS. 3 and 5  is shown. A first displacement sensor  230  and second displacement sensor  240  are integrated into a non-reciprocating element  602  of the reciprocating device  600 . The first displacement sensor  230  senses a vibration signal produced by changes in the distance  232  between the reciprocating element  610  along the Y-axis (i.e., along path B) while the second displacement sensor  240  senses a vibration signal produced by changes in the distance  242  between the reciprocating element  610  along the X-axis (i.e., along path C). That is, each displacement sensor  230 ,  240  measures a change in the clearance  606  between the reciprocating element  610  and the non-reciprocating element  602  caused by anomalous or aberrant movement of the reciprocating element  610 . 
     In the embodiment of  FIG. 7 , the displacement sensors  230 ,  240  are integrated into the reciprocating element  610  rather than the non-reciprocating element  602 . As in the embodiment of  FIG. 6 , each displacement sensor  230 ,  240  measures a change in the clearance  606  between the reciprocating element  610  and the non-reciprocating element  602  caused by anomalous or aberrant movement of the reciprocating element  610 . 
     Referring now to  FIGS. 8 and 9 , graphical representations  900 ,  902 , respectively, are shown, as might be used in analyzing components of the vibration signal. In  FIG. 8 , the graphical representation  900  shows the displacement of the reciprocating element between its proximal  910  and distal  910 ′ positions and a “low-pass” component  912  of the vibration signal. As can be seen, the low-pass component  912  exhibits increased amplitude  912 A as the reciprocating element reaches its distal position  910 ′ (i.e., as the reciprocating element is fully extended by the rod ( 112  in  FIG. 1 )). It is possible that the increased amplitude  912 A is expected at this point of the path of the reciprocating element. It may also be possible, of course, that the increased amplitude  912 A is indicative of anomalous or aberrant movement of the reciprocating element, which may portend decreased efficiency or even impending failure of the reciprocating device. 
     In  FIG. 9 , the graphical representation  902  shows a “high-pass” component  914  exhibiting two areas of increased amplitude  914 A,  914 B, each at approximately the same point between the proximal  910  and distal  910 ′ positions of the reciprocating element. The areas of increased amplitude  914 A,  914 B may indicate, for example, an obstruction or defect along the path of the reciprocating element, which the reciprocating element encounters during both the proximal-to-distal stroke and the return distal-to-proximal stroke. 
     Comparing the low-pass  912  and high-pass  914  components of  FIGS. 8 and 9 , it can be seen that the separate analyses of these components affords much greater diagnostic potential than would analysis of an unseparated vibration signal. If the low-pass component  912  and high-pass component  914  were to be overlaid, for example, the resulting signal may appear to exhibit three periodic increases in amplitude. By separating the vibration signal into components having different frequency ranges, or by separately sensing such components, it is possible, as shown in  FIGS. 8 and 9 , to better detect and diagnose anomalous or aberrant movement of the reciprocating element. 
       FIG. 10  shows a flow diagram of an illustrative method according to the invention. At D, a vibration signal is sensed. As described above, this may include sensing the vibration signal as a whole or a component thereof. At E, it is determined whether the vibration signal sensed at D is to be separated into two or more components. If not (i.e., “No” at E), as may be the case where a component of the vibration signal was sensed at D, an additional component is sensed at F. It should be noted that, in such a case, both components may, and often would, be sensed simultaneously. 
     If the vibration signal is to be separated (i.e., “Yes” at E), the signal is separated into first and second components at G. As noted above, the vibration signal sensed at D may be separated into more than two components, the use of only two components here being for the sake of simplicity. In some embodiments of the invention, the frequency ranges of the first and second components are substantially non-overlapping. Finally, at H, the components are analyzed. Such analysis occurs irrespective of whether a “raw” vibration signal was sensed and subsequently separated into the components to be analyzed or the components themselves were separately sensed. 
     Analysis may, in some cases, include comparing the sensed vibration signal and/or its component(s), or data reflecting some manipulation thereof, to one or more reference signals or patterns of movement. Similarly, analysis may include storing some form of the vibration signal and/or its component(s), or data reflecting some manipulation thereof, for comparison to vibration signals and/or components sensed at another time. 
     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 related or 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.