Piezoelectric vibration sensor

A contact sensor for the repeatable detection of small, high frequency mechanical vibrations in external systems is presented herein. The sensor includes a metal housing with an attachment device at one end and an output at the other end. Inside the metal housing is a core assembly that includes a piezo transducer assembly suspended or isolated between an actuator and a biasing device. The actuator may be in the form of a ceramic sphere that sits at least partially within a recess on the inside of the housing and is in physical contact with the piezo transducer assembly. The biasing device may be in the form of a spring that causes the piezo transducer assembly to be pressed against the actuator at a contestant and known amount of tension.

FIELD OF THE INVENTION

The present invention is generally directed to a sensor, and in particular, a contact sensor for detecting vibrations present in mechanical, rotational, electrical, pressurized or other external systems or equipment. The sensor may be fixedly attached or removably mounted to the system or equipment that is to be measured, and in some cases, the contact or vibration sensor may be sensitive to a small or narrow range of vibration frequencies via a suspended or isolated piezoelectric transducer.

BACKGROUND OF THE INVENTION

Contact probes are used to detect the presence of vibrations or frequencies in various systems including, but certainly not limited to rotating equipment, for example. Many of these devices are handheld probes or wands that are sensitive to mechanical resonance via the use or incorporation of a transducer, such as a piezoelectric transducer. For example, a piezoelectric transducer will bend or deform in the presence of vibrations imparted by the piping or other system that is being tested. However, the piezoelectric transducer in many contact probes can be sensitive to a number of other extraneous vibrations or signals not generated by the system, which can, therefore generate false or misleading information.

For example, in addition to the vibrations that may be caused by or are present in the system or equipment being tested, sound waves or other vibrations in the surrounding air can have an impact on the piezoelectric transducer. In addition, the user holding or operating the contact sensor can potentially impart some vibrations or noise to the transducer. For example, the pressure with which the user holds the contact sensor against the system may have an impact on the piezoelectric transducer. Specifically, even if the user attempts to hold the sensor steady and at a constant pressure against the system or equipment, there will be some movement, variance or some degree of unsteadiness that can impact the piezoelectric transducer.

These, and many other extraneous vibrations or signals, can cause the contact sensor to generate false reads or misleading information.

Accordingly, there is a need in the art for a new contact sensor that can effectively isolate the piezoelectric transducer to minimize, reduce and in many cases, eliminate extraneous signals being imparted onto the transducer. It would also be beneficial for the proposed contact sensor to provide enhanced sensitivity to small vibrations, for example, those that may be in the range of 40-50 kHz.

SUMMARY OF THE INVENTION

The present invention is generally directed to a contact sensor or probe that includes a housing with an attachment bolt, or other attachment mechanism, at one end and an electrical connector, output or transmitter at the other end, for example. In some embodiments, the housing may be constructed of a metal, although other materials are contemplated. Inside the housing is a core assembly that includes a piezoelectric (or other like) transducer suspended or isolated between an actuator and a biasing device. For instance, the actuator, in some cases, may be in the form of a sphere or ball that sits at least partially within a recess on the inside of the housing and is in contact or engagement with the piezoelectric transducer assembly. In particular, the spherical configuration allows the actuator to be in small or minimal contact with the transducer assembly, although enough contact to transfer vibrations within the spirit and scope of the various embodiments of the present invention. In at least one embodiment the actuator may be constructed of ceramic, although other materials may be used within the scope of the present invention. Furthermore, as described herein, the biasing device may be a spring or foam backing, for example, that causes the piezo transducer to be pressed against the actuator at a constant and known amount of tension.

In this manner, the contact sensor of the various embodiments of the present invention allows for the repeatable detection of very small, high frequency mechanical vibrations in external systems to which the contact sensor is mounted or attached. For instance, the external system may be any mechanical, electrical, rotational or pressurized system or equipment, and the vibrations detected by the contact sensor may often correlate with or be determinative of the presence of undesirable conditions such as leaks, electrical discharges, or mechanical wear or failure.

In many embodiments, the contact sensor of the present invention provides enhanced sensitivity for the detection of small vibrations, which in some instances may be in the range of 40-50 kHz, although other ranges, either higher or lower, may be detected. For instance, the contact sensor may be modified to enable a variety of frequencies to be detected, for example, by adjusting the size and/or thickness of the piezo element or wafer, and in some cases, the housing, too.

In particular, the vibrations or signals may be transferred through the housing of the contact sensor to the actuator, which, as mentioned herein, may, in some cases, be a ceramic sphere or ball. Since the ceramic sphere or actuator is in contact with and disposed between the housing and the piezo transducer (e.g., the transducer is held in tension against the ceramic sphere or actuator via a spring, foam backing or other biasing device or mechanism), any vibrations or signals transferred from the housing to the actuator will be imparted directly to the piezo transducer. The piezo transducer will then transmit the detected signal to a PCB (printed circuit board), control board, processor, and/or an output/connector extending out of the housing. In this manner, external processing equipment, wires, cables, etc. can be connected to the output in order to receive, store or further process the data detected by the contact sensor of the present invention. Alternate electrical connectors can be incorporated into the sensor to enable additional equipment to receive the signals. Also, some embodiments may include pre-conditioning electronics or modules, for example, to enable buffering, signal filtering, and/or amplification using signal conditioning methods or techniques.

These and other objects, features and advantages of the present invention will become more apparent when the drawings as well as the detailed description are taken into consideration.

DETAILED DESCRIPTION OF THE INVENTION

As shown in the accompanying drawings, and with particular reference toFIGS. 1 and 2, for example, the present invention is directed to a contact sensor, generally shown as10, for detecting vibrations or other movements in other systems or equipment.FIGS. 3A, 3B, and 3Cshow a top, bottom and side view, respectively, of at least one exemplary embodiment of the contact sensor10of the present invention. It should be noted that any dimensions, sizes or ratios illustrated or mentioned herein should be considered exemplary and not limited in any manner.

For instance, in some embodiments, the contact sensor10of the present invention may operate to detect a narrow range of vibration frequencies between approximately 40 kHz and 50 kHz, although other ranges higher or even lower than this are contemplated within the full spirit and scope of the present invention. In this manner, the contact sensor10can be used to accurately detect small mechanical vibrations, water leaks in a piping system, mechanical failure or wear, etc.

In particular, the contact sensor10of at least one embodiment of the present invention includes a housing12, which can be constructed of a durable and preferably rigid material such as metal, although other materials may be contemplated. Also, as shown in the embodiment ofFIGS. 1 and 2, the housing12may include a general cylindrical shape or configuration with an attachment piece or device7on one end and an output connector2on the other end. However, it should be noted that other shapes, sizes and configurations, as well as locations of the attachment piece or device7and/or the output connector2are contemplated within the scope of the various embodiments disclosed herein.

For instance, the attachment piece or device, represented as7, may be used to connect, mount or fixedly attach the contact sensor10, and in particular, the housing12, to the external system, such as any mechanical, electrical, rotational, or pressurized system or equipment (not shown) of which the contact sensor10will measure or detect vibrations or other movements. Particularly, the attachment piece or device7may attach or mount directly to the system or equipment to be tested. In some cases, however, the attachment piece or device7may attach or mount to an adapter, intermediate mount, screw, etc., that, in turn, attaches or mounts to the system or equipment. As an example, the adapter (not shown) may include a magnet such that the attachment piece or device7of the present invention screws into or otherwise attaches to the adapter, and the adapter is magnetically coupled to the system or equipment. Of course, other attachment devices, adapters, etc. are contemplated in the full spirit and scope of the present invention.

In this manner, and as just an example, the external system may be a piping system through which water or other fluid flows. In such a case, the contact sensor10of the present invention may be operable to accurately detect the presence of vibrations or movements commonly associated with or determinative of a leak in the system, for example.

In any event, the attachment piece or device7may include a threaded protrusion or extension as shown inFIGS. 1 and 2, for example, which may cooperatively attach or screw onto a corresponding mount or piece attached to the external system (not shown), or as mentioned above, to an adapter or other intermediate attachment device. As just an example, the attachment piece7may be a grease fitting or a ZERK fitting, although virtually any fitting, connection, or adapter may be used in order to facilitate the fixed or removable attachment of the contact sensor10to an external or other system or equipment. For instance, many embodiments may include any attachment piece(s) or device(s) that allow(s) the contact sensor10of the present invention to be mounted to the system, either removably mounted, fixedly mounted or permanently mounted.

Furthermore, as shown inFIGS. 1 and 4, the contact sensor10of at least one embodiment of the present invention includes a core assembly20which may include, for example, a transducer or transducer assembly1, an activator6, and a biasing device5. For instance, the transducer1of at least one embodiment may include one or more piezo or piezoelectric element(s), stack(s), wafer(s), etc. that is/are capable of generating a current or other electrical signal when the piezo element(s) is/are bent or deformed from vibrations or other movements. For example, the transducer or transducer assembly1may include one or more contact wafers or discs, represented as1a, as well as one or more structural support elements shows as1b,1c,1d. Collectively, the contact wafer or disc1aand the at least one structural or additional elements1b,1c,1d, are referred to herein as the transducer, transducer assembly, piezo, or piezo assembly, and referenced as1. As provided, the transducer assembly1is structured and configured to detect vibrations or other movements imparted thereto via the actuator6, which in some embodiments is a ball or spherical element. Furthermore, as described and shown herein, in at least one embodiment, the piezo element or transducer assembly1may be suspended, isolated or disposed between the activator6and the biasing device5in that the transducer assembly1only contacts the actuator6and the biasing device5. In such an embodiment, the transducer assembly1makes no additional contacts with the housing12or core mounting assembly4, as described herein.

Referring to the cut-away view ofFIG. 1, the activator6is disposed in contact with or between the housing12(such as an inner surface or a surface on an interior portion of the housing12) and the transducer or piezo element1. Specifically, in at least one embodiment, the housing12may include a recess, indent or dimple16within which at least a portion of the activator6is disposed. The recess, indent or dimple16may function to at least partially retain or hold the activator6in position. For example, in some embodiments, the activator6may be in the form of a sphere or ball bearing, and consequently, the recess, indent or dimple16may be similarly sized and shaped (e.g., a partial concave rounded configuration) in order to receive a portion of the activator6therein. In particular, the spherical configuration of the actuator6allows the actuator6to be in small or minimal contact with the transducer assembly1, although enough contact to transfer vibrations from the external system to the housing12and actuator6, and then to the transducer assembly1, within the spirit and scope of the various embodiments of the present invention.

In addition, it should be noted that the activator6of at least one embodiment of the present invention may, but need not necessarily, be constructed of ceramic or a substantially ceramic material such that the activator6, in some cases, may be a ceramic sphere or a ceramic sphere or ball bearing. However, it is contemplated that the activator6may be constructed of different materials and in a different shape or configuration.

It should also be noted that in some embodiments, the activator6or ceramic ball, as well as the corresponding recess16, may be positioned proximate to the mount or attachment device7, and in some cases, below or substantially in line with the mount or attachment device7, as shown inFIG. 1, for example. For instance, since the activator6is structured to transfer vibrations or other movements from the external system, through the mount7and/or housing12, through the activator6and to the transducer1(e.g., to the contact disc, wafer, or element1a, thereof), placing the activator6proximate the mount7or proximate the portion of the housing12that may be in contact with the external system can provide accurate results. However, in other embodiments, the location of the activator6and recess16may be further from the mount7.

Still referring toFIG. 1, the transducer1or piezo element is connected or mounted (either directly or indirectly via one or more mounting structures) to a biasing device5, which in the embodiment illustrated includes a mechanical or other like spring, although other biasing devices such a foam backing or foam piece are contemplated. For instance, the biasing device5may be mounted to or otherwise engage a base3at one end and is structured to bias the transducer1such that the transducer assembly1or piezo element is held in constant tension against the ceramic sphere or activator6. In this manner, the piezo element or transducer1is suspended or mounted between the activator6and the spring or biasing device5.

Specifically, in at least one embodiment, the transducer assembly1(including the contact element1aand/or any additional transducer mounting structures or elements1b,1c,1d) is only in contact with the activator6, on one end, and the biasing device5, on the other end. For instance, the transducer1, in some embodiments, may not contact the housing12directly, but only indirectly, for example, through the activator6. Accordingly, the transducer1of such an embodiment is suspended between the activator6and the biasing device5and does not contact any other components, walls or surfaces. The biasing device5provides constant pressure against the transducer1, thereby minimizing or even eliminating potential interferences that can distort the transducer's effectiveness.

Furthermore, a printed circuit board (PCB) or other circuit board, controller, or like device may be part of the core assembly20, for example, as part of the base3or other component or core assembly. The PCB or other like device may be used to receive the signals from the transducer1, which can then be stored, processed and/or transmitted to external processing equipment (not shown) or a cable (not shown) via an output connector2. For instance, the output connector2may be in the form of a BNC connector, such as a Micro-BNC connector, or other like connector that can communicate the signals developed by the transducer1and/or the PCB to external equipment or devices. In some cases, the output2may be a wire, and in other embodiments, the output2may transmit the signal(s) wirelessly to external devices or equipment.

Still referring to the cut away view ofFIG. 1, at least one embodiment of the present invention may further include a core mounting assembly4structured to mount or attach the core assembly20to the housing12. In some embodiments the core assembly20may be fixedly attached or connected to the core mounting assembly4, whereas in other embodiments, the core assembly20may be connected to the core mounting assembly4via pressure, friction or other contact or engagement therewith.

Specifically, in the embodiment illustrated, the housing12includes an inner portion13with an inner wall having a threaded pattern14or other like feature(s) thereon. Similarly, the core mounting assembly4may include a corresponding threaded pattern4A on an outer wall thereof, such that the core mounting assembly4can be threaded or screwed into the inner portion13of the housing12, for example, through an open end, generally referenced as12a. The core mounting assembly4may engage, contact or be attached to the core assembly20(e.g., at or near the base3) such that as the core mounting assembly4is screwed into the housing12, the transducer1will be pressed against the actuator6or ceramic sphere that is seated in the recess16.

For instance, in at least one embodiment, the core mounting assembly4may include a contact ledge4B that may be attached to or otherwise engages or contacts the base3, such as a bottom surface3A of the base3. This will, therefore, mount the core assembly20within the inner portion13of the housing12while the transducer assembly1(e.g., piezo element) is suspended between the biasing device5(e.g., spring or foam material) and the actuator6(e.g., ceramic sphere), and therefore, the transducer assembly1will remain electrically isolated. In this manner, only the vibrations from the actuator6will impact the transducer assembly1, allowing the transducer assembly1to provide an accurate and precise reading, sometimes in the narrow range of 40-50 kHz. Extraneous vibrations, movements, or interferences, such as, for example, other impacts on the housing, pressure from a user's hand, or air vibrations, will not impact the transducer assembly1in any significant manner, and in many cases, in no manner at all.

Since other modifications and changes varied to fit particular operating requirements and environments will be apparent to those skilled in the art, the invention is not considered limited to the example chosen for purposes of disclosure, and covers all changes and modifications which do not constitute departures from the true spirit and scope of this invention. This written description provides an illustrative explanation and/or account of the present invention. It may be possible to deliver equivalent benefits using variations of the specific embodiments, without departing from the inventive concept. This description and these drawings, therefore, are to be regarded as illustrative and not restrictive.

Now that the invention has been described,