Vibration-sensing field unit

A vibration-sensing field unit includes a base with at least one accelerometer, and a body mounted to the base. The base is composed essentially of a first material, while the body is composed essentially of a second material that is more flexible than the first material to reduce a vibration at the accelerometer caused by a mass supported by the body. In another embodiment, a vibration-sensing field unit includes at least one accelerometer and at least one ultrasonic transducer.

BACKGROUND

Field of the Disclosure

The present disclosure relates generally to industrial facilities and, more particularly, to monitoring of machine parameters in industrial facilities.

Description of the Related Art

Industrial facilities, such as manufacturing facilities, laboratories, research facilities, refineries, other structures, and the like, often use sensors to monitor machine parameters. For example sensors may be used to measure machine parameters such as vibration, acceleration, velocity, sound, electric field, speed, torque, displacement, and the like. It is often desirable to combine multiple sensors into a single device to increase functionality without requiring the installation and maintenance of multiple devices. However, combining sensors may create additional issues. For example, vibration sensors are limited by their mass since larger masses have lower resonance frequencies. Consequently, the mass of vibration sensor devices is often kept below a threshold, limiting the size and amount of components including power source. This in turn limits the operational time of the sensor devices on a given battery charge, resulting in delays, transmission errors, sensor device failures, frequent battery replacement, inefficiencies, greater expense, and safety concerns.

DETAILED DESCRIPTION

FIGS. 1-6illustrate example implementations of a vibration-sensing field unit in accordance with some embodiments. The vibration-sensing field unit is used to monitor one or more machine parameters of at least one machine housed in a facility (which itself may be a machine). The machine parameters may include, for example, temperature, vibration, stress, acceleration, velocity, pressure, liquid level, gas level, gas concentration, sound, electric field, speed, torque, displacement, and any other information that may directly or indirectly indicate the status of a machine or a part of a machine, or an environment in which a machine is located.

The vibration-sensing field unit comprises a base comprising at least one accelerometer to sense vibrations, and a body mounted to the base. The body of the vibration-sensing field unit supports a mass, for example, a power supply, additional sensors, other electronics, and the like. The body is composed essentially of a flexible material, for example, polytetrafluoroethylene (PTFE) (commonly available under the tradename Teflon™), polypropylene, rubber, soft plastic, acetal resin (commonly available under the tradename Delrin™), or the like, while the base is composed essentially of an inflexible material, for example, steel, stainless steel, aluminum, hard plastic, or the like. In some cases the body and base may both be made of metal or plastic, where the body is substantially more flexible than the base. The flexible material of the body allows the field unit to isolate the mass from the accelerometer, such that the accelerometer is able to sense resonance frequencies higher than the resonance frequency of the mass. Such a mass damping structure allows for vibration-sensing field units with greater functionality, since additional mass can be added in the form of additional sensors, additional electronics, power supply, and the like without affecting the accuracy of accelerometer.

As used herein, the term “essentially” is defined as largely but not necessarily wholly that which is specified, and may include what is specified, as understood by a person of ordinary skill in the art. That is, if an object is composed essentially of a material, the object may be composed entirely of the material, or the object may be composed of a combination of the material and other materials such that the object is composed largely of the material.

As used herein, the term “machine” refers to a structure or combination of structures subject to environmental changes or mechanical forces, either self-generated or externally applied. Structures with self-generated mechanical forces include, for example boilers, compressors, generators, transformers, industrial robots, rotating bearings, mills, lathes, grinders, saws, welders, ovens, mining equipment, and the like. Structures with externally applied mechanical forces include, for example, bridges and other spans, buildings, cranes, boat hulls, highways, and the like. Moreover, it will be appreciated that some machines may comprise structures subject to both self-generated mechanical forces and externally-applied mechanical forces.

FIG. 1illustrates an industrial facility vibration-sensing field unit system100for wireless transmission of machine parameter data from a vibration-sensing field unit102detecting at least one machine parameter of a machine104in an industrial facility to a base station106in accordance with some embodiments. In some embodiments the vibration-sensing field unit102may detect any of a variety of machine parameters, including, for example, temperature, vibration, stress, acceleration, velocity, pressure, liquid level, gas level, gas concentration, sound, electric field, speed, torque, displacement, and any other information that may directly or indirectly indicate the status of a machine or a part of a machine, or an environment in which a machine is located.

The vibration-sensing field unit102transmits information related to machine parameters of the machine104to the base station106over a wireless network via a wireless transmitter108at the vibration-sensing field unit102and a wireless receiver109at the base station106. In at least one embodiment, the wireless transmitter108and the wireless receiver109comprise wireless transceivers, such that the base station106may also transmit information over the wireless network to the vibration-sensing field unit102. In at least one embodiment, the wireless transmitter108is housed within the field unit102. Any of a variety of radio technologies may be implemented by the wireless transmitter108and wireless receiver109, such as an IEEE 802.11x (WiFi)-based technology, 900 megahertz (MHz), 268 MHz, or 2.4 gigahertz (GHz) technology, a Global System for Mobile Communications (GSM) technology, a General Packet Radio Service (GPRS) technology, and the like.

As can be seen in detail view112, the vibration-sensing field unit102comprises a body114mounted to a base116. In at least one embodiment, the body114and the base116comprise corresponding threads such that the body114is mounted to the base116by threading the body114onto the base116. In at least one embodiment, the vibration-sensing field unit102further comprises a mount118to facilitate mounting the vibration-sensing field unit102to the machine104. For example, in the illustrated embodiment, the mount118comprises three legs120,121,122oriented to support mounting to a variety of surfaces presented by machine bodies, including uneven surfaces and curved surfaces. In at least one embodiment, the base further comprises a hole at a bottom surface124of the mount118to receive a bolt or otherwise facilitate mounting of the vibration-sensing field unit102to the machine104. The mount118may be rotatable about the y-axis (in the z-x plane) to facilitate positioning of the legs120,121,122or other fasteners on the machine104. In the illustrated embodiment, a lock nut126fastens the mount118to the base116. In some embodiments, the lock nut126fastens the mount118to the body114. Further, in at least one embodiment, once the mount118has been positioned on the machine104, the lock nut126locks the position of the mount118by preventing further rotation of the mount118about the y-axis.

The body114houses a mass128comprising any of a variety of additional components. In the illustrated embodiment, the mass128comprises a power supply130and electronics132. While, in the illustrated embodiment, the power supply130comprises batteries, in other embodiments, the power supply130may comprise any power source. The electronics132may comprise, for example, one or more sensors, a circuit board (e.g., a printed circuit board (PCB)), a wireless transmitter, a radio, a memory store, or the like. In some embodiments, the mass128is supported by one or more boards134,136. For example, in the illustrated embodiment, the power supply130is supported by the battery board136, and the electronics132are supported by the electronics board138. In other embodiments, a single board may be used, or more than two boards may be used. Further in some embodiments, the electronics132and the power supply130may be supported by the same board, or each of the electronics132or the power supply130may be distributed among multiple boards. A standoff may be used, for example, a plurality of metal or nylon bolts140, to separate the boards136,138and create space for the electronics132(or in some embodiments the power supply130). In the illustrated embodiment, the body114further comprises a cover142that allows access to at least a portion of the mass128. For example, the cover142may be removable, or otherwise open to allow access to the power supply130or the electronics132to facilitate maintenance or replacement.

The vibration-sensing field unit102uses an accelerometer housed in the base116to monitor vibrations of the machine104. Vibration in a machine may indicate imbalances, meshing of gear teeth, uneven friction, worn out or failing components, or the like, and may result in unwanted noise, wasted energy, increased wear, machine or part failure, or the like. As such, it is advantageous to identify and remedy the cause of vibrations early. Generally, early signs of unwanted vibrations are much more subtle, having higher frequencies than when the vibration is allowed to continue. As such, the higher the frequency that the vibration-sensing field unit102is able to sense, the better chance of identifying early signs of vibration in the machine104. Accelerometers are only able to sense frequencies lower than the resonance frequency of the accelerometer. The resonance frequency is the frequency at which the accelerometer resonates or rings; that is, the point in frequency within an accelerometer's frequency response where maximum sensitivity is outputted.

The resonance frequency of an accelerometer may be modeled using Equation 1 (EQ. 1):

f=12⁢π⁢kmEQ.⁢1
where f represents the resonance frequency for the accelerometer device having a mass m, and a stiffness factor k. As is indicated by Equation 1 (EQ. 1), the greater the mass m, the lower the resonance frequency f. As such, vibration-sensing devices must maintain a low mass to avoid raising the resonance frequency, thereby reducing the sensitivity of the accelerometer. To achieve this, vibration-sensing devices are often kept very small in size, foregoing increased functionality provided by additional components to avoid additional mass.

The vibration-sensing field unit102of the illustrated embodiment allows for additional mass (and therefore additional functionality) while still maintaining a high resonance frequency at the accelerometer by employing a mass damping system144at the body114of the vibration-sensing field unit102. While the base116of the vibration-sensing field unit102is composed essentially of an inflexible material, the body114of the vibration-sensing field unit102is composed essentially of a flexible material (the flexibleness or inflexibleness of each material being relative to the other). For example, the base116of the vibration-sensing field unit102may be composed essentially of steel, stainless steel, aluminum, hard plastic, or the like, while the body114of the vibration-sensing field unit102may be composed essentially of PTFE, polypropylene, rubber, acetal resin, soft plastic, or the like.

The flexible material of the body114supports the mass128, so as to isolate the mass128from the accelerometer at the base116of the vibration-sensing field unit102. Further, in some embodiments, the mass damping system144employs one or more shock-absorbing pillars146composed essentially of the flexible material so as to absorb the vibration of the mass128, preventing the vibrations of the mass128from affecting the resonance frequency of the accelerometer at the base116of the vibration-sensing field unit102. While in the illustrated embodiment each of the plurality of bolts140extends into each of the one or more shock-absorbing pillars146, in other embodiments the plurality of bolts or other standoff and the one or more shock-absorbing pillars146may be arranged differently.

Conventionally, the resonance frequency of the accelerometer is affected by the total mass of the vibration-sensing field unit, including the power supply, electronics, other structures, etc. In contrast, in the illustrated embodiments, the accelerometer at the base116of the vibration-sensing field unit102will maintain a higher resonance frequency since it will be isolated from the lower resonance frequency of the mass128by the mass damping system144at the body114of the vibration-sensing field unit102. As such, the vibration-sensing field unit102may be customized to provide additional functionality without affecting the effectiveness of the accelerometer. For example, in some embodiments the vibration-sensing field unit102comprises an expansion port, an indicator light, an antenna connector, an ultrasonic transducer, or the like.

FIG. 2illustrates an exploded perspective view of a vibration-sensing field unit200comprising a body202mountable to a base204in accordance with some embodiments. The base204is configured to receive at least one accelerometer206and at least one ultrasonic transducer208. The addition of the at least one ultrasonic transducer208facilitates early detection of certain machine issues that often produce detectible sounds prior to detectible vibrations resulting from, for example, metal deterioration, early signs of bearing failures, fluid or air/gas leaks, and the like.

The accelerometer206and ultrasonic transducer208may be seated in the base204. In the illustrated embodiment, the accelerometer206and the ultrasonic transducer208are mounted to a plate210used in combination with an O-ring212to position the accelerometer206and the ultrasonic transducer208in the base204. The base204may comprise a shelf or other feature such that the O-ring rests on the shelf, and the plate210rests on the O-ring212, such that the accelerometer206is suspended within a cavity of the base204. In the illustrated embodiment, the base204comprises threads213corresponding to threaded opening214of the body202, such that the body202may be threaded onto the base. In other embodiments, the body202may be mounted onto the base204using any of a variety of mounting techniques and fasteners. Further, the base204and the mount236may include co-aligned acoustic channels (not shown) to focus ultrasonic noise onto the ultrasonic transducer208.

The base204is composed essentially of an inflexible material, while the body202is composed essentially of a flexible material (“flexible” and “inflexible” for each material being relative to the other material). For example, the base204of the vibration-sensing field unit200may be composed essentially of steel, stainless steel, aluminum, hard plastic, or the like, while the body202of the vibration-sensing field unit200may be composed essentially of PTFE, polypropylene, rubber, soft plastic, or the like. As another example, the base204may be composed of a relatively inflexible metal, such as stainless steel, while the body202may be composed of a relatively flexible metal, such as aluminum. The difference in flexibility between the base204and the body202allows the body202to serve as a mass damping system, isolating the accelerometer206from vibrations caused by a mass216.

In the illustrated embodiment, the mass216comprises power supply218, electronics220, and supporting structures. However, in other embodiments, the mass216may comprise any of a variety of components. To illustrate, the mass216further may include a piezoelectric, thermoelectric, or peltier cooling system on at least one of the boards, whereby the cooling system cools the field unit200so as to allow it to operate in high temperature environments. In such embodiments, the cooling system may use the body202as a radiator for dissipating heat. The electronics220rest on an electronics board222supported by one or more shock-absorbing pillars224formed in the body202. In the illustrated embodiment, a plurality of bolts226extend through holes in the electronics board222into the one or more shock-absorbing pillars, such that the heads of the bolts226create an offset from the electronics board222allowing space for the electronics220. The electronics220may comprise, for example, one or more sensors, a circuit board (e.g., a PCB), a wireless transmitter, a radio, a memory store, or the like. The electronics220may implement systems for processing signaling from the one or more sensors of the vibration-sensing field unit200or sensors externally coupled to the field unit200via an expansion port, as well as systems for transmitting wirelessly transmitting representations of such processing. For example, the electronics220may include a digital signal processing system, a decimation unit, an anti-alias filter, a fast Fourier transform (FFT) processor, and the like.

A battery board228rests on the heads of the plurality of bolts226, and supports the power supply218. While the power supply218in the illustrated embodiment depicts batteries, in other embodiments, the power supply218may comprise any power source. Additionally, while two boards222,228are depicted in the illustrated embodiment, other embodiments may include more or less boards. Further, the power supply218and the electronics220may rest on the same board, or may be distributed in any manner over multiple boards.

A cover230is removably coupled to the body202to protect the power supply218and electronics220. In the illustrated embodiment, the cover230comprises threads232corresponding to threads234of the body202, such that the cover230may be threaded onto the body202. A removable cover230allows the power supply218or the electronics220to be accessed for maintenance, replacement, or otherwise. While threads232,234are used to removably couple the cover230to the body202, in other embodiments, other fasteners may be used. In at least one embodiment, the cover230is coupled to the body202, such that the cover230may be opened (and the power supply218or electronics220accessed) while remaining attached to the body202.

The base204may be seated in, or otherwise coupled to, a mount236to facilitate mounting of the vibration-sensing field unit200to a machine. In the illustrated embodiment, the mount236is depicted as comprising three legs238and a hole240. The legs238allow the vibration-sensing field unit200to be mounted to any surface, including uneven surfaces and rounded surfaces. The hole240receives a bolt or other fastening component to secure the vibration-sensing field unit200to the machine. Additionally, in some embodiments, the mount236, or a portion of the mount236, is rotatable about the y-axis, such that the position of the legs238may be positioned according to the surface of the machine.

In the illustrated embodiment, an O-ring242and a lock nut244are fitted over the mount236and coupled to the base204. In at least one embodiment, the lock nut244prevents the mount236from rotating further about the y-axis. In at least one embodiment, the lock nut244is threaded to correspond to the threads213of the base204, such that the lock nut244may be threaded onto the base204. In other embodiments, the mount235may be coupled to the base204using any of a variety of fasteners or coupling techniques.

In the illustrated embodiment, the body202of the vibration-sensing field unit200additionally comprises an expansion port246, a light indicator248, and an antenna connector250. The expansion port246facilitates the use of additional components, channels, and features that may share the resources of the vibration-sensing field unit200, including the power supply218, and the electronics220. The light indicator248may be any indicator, for example, a light-emitting diode (LED) indicator to indicate one or more functioning states of the vibration-sensing field unit200. The light indicator may be used to indicate any of a variety of status information, such as through blink patterns indicating machine health, faults in the vibration-sensing field unit200, current battery life, as well as the on/off status of the vibration-sensing field unit200. The antenna connector250facilitates the connection of an antenna, transmitter, receiver, or transceiver. In other embodiments, the body202, and the vibration-sensing field unit200as a whole may comprise any variety of additional connections or components to increase functionality (thereby adding mass) without affecting the function of the accelerometer206.

FIGS. 3-5illustrate a top view, bottom view, and cross-section view of the vibration-sensing field unit200ofFIG. 2in accordance with some embodiments. As illustrated inFIG. 3, the top view depicts the cover230covering the power supply218, and the power supply218resting on the battery board228. The expansion port246and antenna connector250are also depicted in the top view. The vibration-sensing field unit200is depicted inFIG. 3with cutline300-300, the cross-section of which is described in detail below with reference toFIG. 5. As illustrated inFIG. 4, the bottom view depicts the mount236, including the legs238, and the hole240to facilitate mounting of the vibration-sensing field unit200to a machine. Also depicted is the lock nut244for coupling the mount236to the base204. Finally, a perimeter of the body202is depicted, along with the expansion port246, the light indicator248, and the antenna connector250.

FIG. 5is a cross-section view along cutline300-300of the vibration-sensing field unit200ofFIG. 3in accordance with some embodiments. As illustrated, the at least one accelerometer206and the at least one ultrasonic transducer208are mounted to the plate210, which rests on the O-ring212within the base204. The lock nut244and its O-ring242secure the mount236to the base204. While a machine is not depicted in the illustrated embodiment, if the vibration-sensing field unit200is mounted to a machine, the legs238would come in contact with a surface of the machine, and a bolt or other fastener would secure the vibration-sensing field unit200to the machine via hole240.

The base204is coupled to the body202, which supports the mass216(seeFIG. 2) comprising the electronics board222, the electronics220, the plurality of bolts226forming a standoff, the battery board228, and the power supply218. The body202additionally supports the expansion port246, the light indicator248, and the antenna connector250. The one or more shock-absorbing pillars224absorb vibrations caused by the mass216providing additional mass damping. While the shock-absorbing pillars224are depicted as hollow columns, any of a variety of formations may be used to provide the shock absorption. Further, the placement and location of the mass216may differ in different embodiments. Additionally, the location within the base204of the at least one accelerometer206and the at least one ultrasonic transducer208may differ in different embodiments. Finally, the shape of the body202, base204, and vibration-sensing field unit200as a whole may differ in different embodiments, along with the location of any extension (e.g., expansion port246, light indicator248, antenna connector250).

FIG. 6is another example of a vibration-sensing field unit system600in accordance with some embodiments. A vibration-sensing field unit602is mounted to a machine604via a mount606. The vibration-sensing field unit602further comprises a base608housing at least one accelerometer610, and a body612coupled to the base608. The body612supports a mass614, for example, electronics, a power supply, or additional structures or components. The base608is composed essentially of an inflexible material, while the body612is composed essentially of a flexible material (“flexible” and “inflexible” for each material being relative to the other material). For example, the base608of the vibration-sensing field unit602may be composed essentially of steel, stainless steel, aluminum, hard plastic, or the like, while the body612of the vibration-sensing field unit602may be composed essentially of PTFE, polypropylene, rubber, soft plastic, or the like. The difference in flexibility between the base608and the body612allows the body612to serve as a mass damping system, isolating the accelerometer610from vibrations caused by the mass614.

Due to the mass damping effect of the body612, the power supply and other resources may be increased without affecting the resonance frequency, and therefore the function, of the accelerometer610. As such, additional external components616,617,618,619,620,621may use the resources of the vibration-sensing field unit602via an expansion port624and flexible cable613or other flexible wiring. The additional external components616-621, may each comprise a sensor, a circuit board (e.g., a PCB), a transmitter, a receiver, or the like. While the illustrated embodiment depicts six components616-621connected to the vibration-sensing field unit602via the expansion port624, other embodiments of the vibration-sensing field unit system600may include less or more components. Further, in other embodiments, the vibration-sensing field unit602may comprise less or more expansion ports624than depicted in the illustrated embodiment. Such external components can include, for example, radio systems, additional sensors such as accelerometers or ultrasonic probes, a vibration-harvesting system for generating power from vibrational energy, or an external solar panel or other power source.