GB2527942A

GB2527942A - Monitoring device

Info

Publication number: GB2527942A
Application number: GB1511809.4A
Authority: GB
Inventors: Ian Newby; Stephen Mottishead
Original assignee: AES Engineering Ltd
Current assignee: AES Engineering Ltd
Priority date: 2014-07-04
Filing date: 2015-07-06
Publication date: 2016-01-06
Also published as: GB201411995D0; US20160003668A1; GB201511809D0

Abstract

A condition monitor measures vibration and/or temperature of a piece of equipment and/or structure and comprises an enclosure, within which is at least one vibration sensor 16 sensing vibrations about axes of orientation, at least one temperature sensor 20, a processor 12 for analysing signals, and a power source 14; the analysed signals are stored, the monitor is mounted on the equipment or structure, and the monitor connects to another device wirelessly or with wires. Only statistically differing data readings based on the percentage mean or mode may be compared and stored. The axes of orientation may be horizontal or perpendicular to the mounting base or co-axial with the longitudinal axis of the shaft. Parameters such as peak or overall acceleration, velocity, or displacement, temperature or crest factor may be determined. The power source may be a battery and may generate power from the equipment or environment. The condition may be indicated by coloured LEDs 28a-28c or an alarm. A separate wall mounted device, modem, PDA, tablet or Smartphone may connect via Bluetooth, WiFi, or 3G to upload or download data from the monitor.

Description

Monitoring Device

Field of the Invention

This invention relates to monitoring devices for monitoring the condition of machinery through vibration and/or temperature readings.

Background to the Invention

Machinery, especially machinery with moving parts, can, overtime, develop problems during operation. This may be due to misalignment of parts, wear on parts or other issues, which may subsequently lead to further problems and failure.

Condition based maintenance (CBM) and condition monitoring (CM) is the detection of symptoms through the measurement of one or more parameters which may be indicative of a fault condition, either by an increase or decrease in the overall measured value, or by some other change to a characteristic value such as root-mean-square value (r.m.s.), peak value (pk), frequency component amplitude, paftern and/or distribution, etc. Vibration monitoring (VM) is a particular technique used in condition monitoring. Vibration is the mechanical movement of a machine or asset which may be periodic (regular) or random and contains characteristic symptoms of a wide range of machine faults, including: unbalance, misalignment, poor bearing lubrication, gear faults, motor winding & rotor faults, bearing damage, etc. It is particularly effective for monitoring rotating and reciprocating machines.

Vibration monitoring utilises vibration sensors or transducers to detect the vibration signal.

The vibration signal may then be conditioned, filtered and processed using analysis instrumentation and software.

Common sources of poor vibration measurements, which limits the efficiency of CM arrangements, include, poor sensor contact, faulty attachment, operator error, cable faults, ground loop, transducer fault, instrument fault, low instrument voltage and/or change of probe/magnet.

Various transducers are available for detecting vibrations in machinery and one particular system uses a portable digital assistant (PDA), which connects to a sensor device using a cable to download the information. The information can then be uploaded to a web-based server from the PDA. One of the problems with such an arrangement is that a user needs clear access to the device in order to upload information via a cable. Additionally, one not trained to interrogate the device is unlikely to identify any issues that may occur during use of the machines. Therefore, a problem may go unnoticed until a trained user is able to attend the site, interrogate the device and interpret the information collected. Furthermore, where a user needs access to the device, it may not be possible to locate the device in a position in which an efficient and effective reading may be taken, thereby limiting the use of the device.

Added to this, traditionally for accurate sampling and diagnostics to be achieved three vibration readings are taken near each bearing in an asset; for example readings would be taken at both ends of a motor as close to the bearing as possible, each indicating different potential faults. These three readings are commonly:- 1. Horizontal, where the accelerometer is in line radially with the mountings which can indicate imbalance in the machine, radial mis-alignment, and/or looseness 2. Vertical perpendicular to the mountings which can indicate bearing defects or failure 3. Axial, in line with the motor shaft which can indicate angular misalignment or thrust bearing problems Due to the number of readings potentially required on a site the time per reading can be limited affecting the accuracy of the reading and also the cost of the condition monitoring can be expensive.

AES Engineering patent GB1400942 teaches of a device which can allow remote sensing to be possible thereby allowing effective readings to be taken. However it is limited to taking one reading per device thereby requiring multiple remote sensors to be fitted to the asset in the orientations listed above. This means it can be costly to implement and evaluate the data reducing the thoroughness of coverage of assets on a site. Furthermore, when used remotely, due to the amount of data storage being finite (often being limited to 50 readings before downloading is required) it is necessary to compromise on either the frequency of readings taken or frequency of downloading of data. Battery life is again finite and so can also be a limiting factor as the indication means, such as light emitting diodes, can reduce the time that the device can be left on the assets before it requires removing and recharging due to the power drawn from the battery being higher. Both of these factors therefore mean that a compromise is necessary to be found between the frequency of readings, downloads or the level of visual indication and this compromise potentially reduces the quality of readings taken and increases the amount of labour and investment in devices which is required.

Summary of the Invention

Accordingly, the present invention is directed to a condition monitor that monitors vibration and/or temperatures of a piece of equipment and/or a structure, the monitor comprising: an enclosure; at least one vibration sensor located in the enclosure wherein vibrations are sensed about more than one axis of orientation; at least one temperature sensor located in the enclosure; a processor located in the enclosure and being connected to at least one of said sensors for analysing signals produced therefrom; means located in the enclosure for storage of the analysed signals; a power source connected to the processor and located in or in close proximity to the monitor means for mounting the monitor on the piece of equipment or the structure; and means for connecting the monitor to a secondary device wirelessly or with wires.

Preferably, the monitor includes means for comparing analysed data and storing in the storage means only data readings are statistically different to previous readings that have been taken. Statistically different may, but not be limited, be a percentage mean or mode related difference to the previous readings. The device may include means for setting the difference which required to trigger the storage of data. The setting means may include an integral or remote control to alter the setting. The percentage difference may be at least 15%, preferably 10%.

Preferably, the monitor includes a read or write memory chip, allowing the finite storage resource, preferably capable of storing at least 50 pieces of data, to be used most efficiently.

This limitation of stored data has a number of benefits which include: reducing the time it takes to download the data to a secondary device, and reducing the size and power usage of the storage means. Furthermore, the increments between download to a secondary device can be increased allowing the monitoring device to be used in extremely remote locations that do not have permanent connection to a computer network.

Preferably, the axis of orientation that the device can measure vibration about are horizontal and perpendicular to the mounting base and along the axis of the shaft and can be analysed with or without simultaneous temperature readings to give a number of resultant parameters which include, but are not limited to overall acceleration, overall velocity, peak acceleration, temperature, peak displacement, overall displacement, peak velocity and crest factor.

The monitor may include an alarm feature allowing alarm to be automatically calculated based on statistical analysis of the readings collected or manually set. The calculations may make use of the historical readings for the particular application thereby allowing the alarm levels to be set specifically for the application. As a result, a lay-person may more easily interpret the readings and determine the appropriate course of action.

A power source for the device is preferably a battery but could also be a device that is capable of generating power from the equipment or environment or a combination of both. The benefit of this is that the battery could have an extended or infinite life, enabling the monitor continuously to take samples with no compromise on location or frequency of sampling.

Preferably, the monitor includes means for connecting it to a separate device which in turn is connected to a network wirelessly or with wires together with a number of other monitors.

This could be achieved by low energy Bluetooth wireless connection which allows the battery life of the monitor to be optimised not requiring a compromise on the frequency of data downloads to be necessary. Accordingly, the present invention further provides a condition monitoring assembly comprising one or more monitors of the invention and, connected or connectable thereto, a separate device which in turn is connected to a network wirelessly or with wires.

The separate device may be a wall mounted device, a modem, a handheld PDA, a tablet or a Smartphone which has a separate power source to the monitor and therefore can allow transfer of power to the monitor should it be connected through a wired connection. The separate device may be wirelessly connected to a network via WiFi or 3G allowing remote use of the monitor and the separate device.

The downloading of information between the separate device and the or each monitor may be carried out automatically allowing data to be sent remotely via an application or piece of software across the network for analysis thereby reducing human interaction with the devices.

In an embodiment of the present invention, data may be uploaded to the monitor remotely, via two-way wireless connectivity, allowing parameters in the sensor to be remotely configured.

These parameters may include but are not limited to alarm levels, time frequency and duration of the periods over which vibration and temperature readings are taken and stored. Updates and amendments can be made by an authorised user logging in to the monitor and making changes in a software-based control panel which updates parameters via an internet connection, through a local wireless gateway to each sensor. Examples of where remote configuration may be used include: on machine start-up or run-down where additional readings are required for a short space of time and where the alarm levels within the sensor are clearly too high or low for the operating environment and need to be adjusted.

The monitor may be provided with visual indication means which indicate the condition of the piece of equipment via one or more light emitting diodes. Preferably, the one or more diodes are capable of indicating at least three different equipment conditions via at least three different colours, thereby allowing a lay-person to visually interpret the condition of the equipment and take the appropriate action.

The present invention also provides a method of monitoring vibration and/or temperatures of a piece of equipment and/or a structure, the method mounting a monitor of the invention on a piece of equipment or a structure, using the monitor to sense vibrations and produce signals relating thereto and analysing the signals to produce data and storing the data within the monitor.

Brief Description of the Drawing

The accompanying drawing is a diagram showing the arrangement of components in a monitor of the present invention.

Detailed Description of the Invention

An embodiment of the invention will now be described, by way of example only, and with reference to the accompanying drawing.

The drawing shows a condition monitor 10 having a central processor 12 connected to a power supply 14 in the form of a battery. The device comprises a MEM5 accelerometer 16, which is connected to the processor 12 via an analogue to digital converter 18. The processor 12 is also connected to an input in the form of a temperature sensor 20.

A transmitter 22 and a receiver 24 are provided and are in communication with the processor 12. The device is provided with memory 26 connected to the processor 12 and a visual indicator in the form of a plurality of LEDs 28 is also connected to the processor 12. The LEDs 28 each correspond to a particular measured or calculated parameter.

When in use, the device 12 is connected to machinery to be monitored and the MEMs sensor 16 monitors vibration levels. The received signal is passed through the analogue to digital converter 18 to the processor 12, where it can be analysed. The processor 12 is given a default setting to provide the following information from the signal received: vibration overall velocity amplitude (r.m.s.) derived from a power spectrum in units of mm/s; vibration overall acceleration amplitude (r.m.s.) derived from the vibration acceleration waveform in units of g (where g = 9.81 mIs2); and vibration peak acceleration amplitude (pk) derived from the vibration acceleration waveform in units of g (where g = 9.81 mIs2).

The calculated values are then compared to predetermined limits and an appropriate level of concern attached to that value. The processor 12 then sends a signal to the visual indicators 28 according to the level of concern assigned to the parameter. For example, different colours may be displayed according to where the parameter is located on a scale; the colour displayed may vary according to whether the measurement or calculated value is below the predetermined safe' range, within range, above the range (warning) significantly above the range (alarm) and alarmingly above the range (alarm).

The temperature sensor 20 may be provided with a visual indicator in order to indicate when the temperature of the machinery is above a predetermined threshold.

The information received by the processor 12 from the sensor 16, and any values calculated from that data, may be recorded in the memory 26, which is non-volatile memory. The arrangement may be such that data storage only occurs when data differs from previously stored data by more than a predetermined amount. The data stored can t be accessed as and when required and the data for the machinery over time can be available to a user. The data may be undeletable so that it stays with the machinery and anyone needing to review the machinery will have access to the data over the lifespan of the machinery, or at least from when the monitor 10 was installed. Where machinery fails, the memory 26 can be recovered and interrogated to provide information on the cause of the failure.

The memory 26 may be used to store a time trace, especially a vibration acceleration time trace, which allows processing of acceleration, velocity and displacement spectra. The sampling frequency and rate and the number of samples can be configured to suit the application.

The transmitter 22 and the receiver 24, which are powered by the battery 14, allow a user to communicate with the processor 12 and to access the memory 26. The user can download information from the monitor 10, or can programme the processor 12 to adjust the predetermined values or to configure/reconfigure it to calculate different parameters. The transmitter 22 and receiver 24 may be in the form of a short-range radio transmission device, for example Bluetooth®, or another form of wireless transmission or wireless data exchange.

Where the system forms part of a commonly used form of wireless transmission, it can send and receive information to and from a PDA, a smartphone, a laptop computer and/or a tablet.

Where a wireless network is set up, the monitor 10 may be connected to that network to allow the transmission and reception of information in real time.

The device allows for the post mortem storage of multiple dynamic and static measurements, full waveform (time trace) storage for vibration measurements, ISO vibration alarms and configurable alarm sets, frequency ranges (for example, 2 to 250 Hz, 2 to 1000 Hz or 10 to 1000Hz), and a unique sensor ID (GUID).

The sensor device may be an integrated Electronics Piezo-Electric accelerometer (IEPE).

An audible alarm system and/or an automatic signal transmission programme may be incorporated into the device and, where the measured parameter and/or calculated value is above a particular pre-set level, the device may issue an alert.

A plurality of sensors may be incorporated into the device in order to calculate or measure more than one parameter. Further indicators (visual or otherwise) may be provided to show whether the machinery is operating as expected.

The units in which the data is recorded and the calculated parameters can be adjusted according to the user's requirements using the transmitter and receiver to programme the processor.

The invention integrates a CF2 A-D card and an IEPE transducer power interface board into a combined A-D and IEPE power board. This also includes a Bluetooth interface to the PDA, thus obviating the requirement for a cable and plug FDA data connection. a

In a further embodiment of the present invention, the battery of the above-described condition monitor is replaced or supplemented by means for connecting the monitor to a mains power supply.

Claims

Claims 1. A condition monitor that monitors vibration and/or temperatures of a piece of equipment and/or a structure, the monitor comprising: an enclosure; at least one vibration sensors located in the enclosure of the monitor whereby vibrations are sensed about more than one axis of orientation; at least one temperature sensor located in the enclosure; a processor located in the enclosure and being connected to at least one of said sensors for analysing signals produced therefrom; means located in the enclosure for storage of the analysed signals; a power source connected or connectable to the processor and located in or in close proximity to the monitor; means for mounting the monitor on the piece of equipment or the structure; and means for connecting the monitor to a secondary device wirelessly or with wires.
2. A monitor according to Claim 1, wherein the device includes means for comparing analysed data and storing in the storage means only statistically differing data readings.
3. A monitor according to Claim 2, wherein the statistically differing data reading are percentage mean or mode related differences to the previous readings.
4. A monitor according to Claim 3, where the percentage means or mode related difference is at least 15%.
5. A monitor according to Claim 4, wherein the percentage mean or mode difference is at least 10%.
6. A monitor according to any of Claims 3 to 5, where the device includes means of setting the difference to the previous readings which will result in data storage.
7. A monitor according to any of previous claims, wherein the storage means is capable of storing at least 50 pieces of data.
8. A monitor according to any of the preceding claims, wherein the axes of orientation are two or more of axes horizontal and perpendicular to the mounting base and co-axial with the longitudinal axis of the shaft.
9. A monitor according to any of the preceding claims, wherein the processor is arranged so that three vibration readings can be analysed with or without temperature readings to give one or more resultant parameters.
10. A monitor according to any of the preceding claims, wherein the processor is arranged to process both vibration and temperature readings and to calculate parameters therefrom for simultaneous recordable.
11. A monitor according to Claim 107, wherein the parameters include one or more of overall acceleration, overall velocity, peak acceleration, temperature, peak displacement, overall displacement, peak velocity and crest factor.
12. A monitor according to any of the preceding claims, wherein the monitor includes means for automatically calculating alarm levels based on statistical analysis of readings collected or manually set.
13. A monitor according to any of the preceding claims, wherein the storage means has read and write capability.
14. A monitor according to any of the preceding claims, wherein the power source is a baftery.
15. A monitor according to any of the preceding claims, wherein a separate device is provided to download data from and/or upload data to the monitor.
16. A monitor according to any of the preceding claims, wherein the power source generates power from the equipment or the environment or a combination of both.
17. A monitor according to any of the preceding claims, wherein the mounting means is a threaded or magnetic component.
18. A monitor according to any of the preceding claims, wherein the monitor includes means for automatically downloading data via an application or piece of software remotely to a remote network for analysis of the data
19. A monitor according to any of the preceding claims, wherein the monitor is arranged for data to be uploaded to it wirelessly or with wires from a separate device.
20. A monitor according to any of the preceding claims, wherein the monitor is arranged so that parameters on the monitor can be configured remotely.
21. A monitor according to Claim 20, wherein the parameters include one or more of alarm levels, time frequency and duration that vibration and temperature readings are taken and stored.
22. A monitor according to any of the preceding claims, wherein the monitor includes visual indication means which indicate the condition of the piece of equipment via one or more light emitting diodes.
23. A monitor according to Claim 22, wherein the light emitting diodes are capable of indicating at least three different equipment conditions via at least three different colours.
24. A condition monitoring assembly comprising one or more monitors according to any of the preceding claims and, connected or connectable thereto, a separate device which in turn is connected to a network wirelessly or with wires.
25. An assembly according to Claim 24, wherein connection or connectability is by a low energy Bluetooth wireless connection, by WiFi or by 3G.
26. An assembly according to Claim 24 to 25, wherein the separate device is a wall mounted device, a modem, a handheld PDA, a tablet or a Smartphone.
27. An assembly according to any of Claims 24 to 26, wherein the separate device has a separate power source to the one or more monitors and can allow transfer of this power to the monitors.
28. A method of monitoring vibration and/or temperatures of a piece of equipment and/or a structure, the method mounting a monitor as claimed in any of Claims 1 to 23 on the piece of equipment or the structure, using the monitor to sense vibrations and produce signals relating thereto and analysing the signals to produce data and storing the data within the monitor.