Communications: electrical – Condition responsive indicating system – Specific condition
Reexamination Certificate
1999-01-22
2001-07-10
Tong, Nina (Department: 2632)
Communications: electrical
Condition responsive indicating system
Specific condition
C340S539230, C340S679000, C340S691100
Reexamination Certificate
active
06259372
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to wireless transducers, and more particularly to the self-powered wireless transducer for monitoring physical conditions in external structure, such as excessive vibrations in a bearing.
In many present day industrial settings, machinery is run 24 hours a day and seven days a week, thereby making it imperative that maintenance be performed at specified intervals and non-orderly shutdowns must be avoided. Any breakdown of such machinery, or a non-orderly shutdown because of a part defect, can result in expensive downtime. One of the largest failure classifications in such industries is motor failure, and motor failure is most commonly associated with internal bearing failures and/or electrical over-heating resulting in insulation breakdown and shorting. Many maintenance personnel and plant managers realize that preventive maintenance is a necessity in such applications, and therefore, periodically replace components, such as entire motors in critical areas with new motors, whether or not they actually need replacement. Such regularly scheduled maintenance may very well be more costly than necessary, but most maintenance personnel and plant managers are willing to pay the cost of replacing an adequately functioning motor, rather than take the risk of a non-orderly shutdown during peak production periods.
Therefore, it would be desirable to have a system and method that could monitor such machinery well in advance of a failure so that maintenance can be performed at scheduled downtimes, while at the same time avoiding replacing perfectly good functioning components. Even a system that can predict a non-orderly shutdown within an hour, allows an orderly shutdown to be accomplished in a period of time in which maintenance personnel can be available with the necessary components that need to be replaced.
Further, each machine may have several motors, and each motor may have several bearings that need to be monitored. It would therefore be desirable to also have a system that could not only detect that there is a problem in a bearing, but to also pinpoint which bearing in which motor needs to be replaced.
It would also be desirable to have such a system that is wireless, which not only makes installation easier, it also avoids unnecessary wires in remote locations that are typically hard to get to and do not have existing low voltage wire harnesses to run the wires thereto. Additionally, it would be desirable to have such a system that is self-powered to avoid scheduled battery replacement.
SUMMARY OF THE INVENTION
The present invention provides a method and apparatus that solves the aforementioned problems and provides information about the well being of the machinery being monitored so that predictive or preventive maintenance can be done in an orderly manner.
In accordance with one aspect of the invention, a wireless transducer includes a housing adaptable to monitor an external physical condition, such as vibrations, of an external structure, for example bearings. The wireless transducer includes a self-contained energy conversion source mounted within the housing to sense the external physical condition and create a power and characteristic signal in response to the external physical condition. This signal is used not only to self-power the circuit and the transmitter, it also contains characteristic information of the external condition. A transmitter is mounted in the housing and connected to the energy conversion source to receive the power and characteristic signal and transmit a monitoring signal that is indicative of the external physical condition. The transmitter receives its power solely from the energy conversion source.
In accordance with another aspect of the invention, a fault detection system includes a plurality of the aforementioned self-powered wireless transducers, wherein each of the self-powered wireless transducers transmits a signal having a distinct address so as to identify which transmitter transmitted that particular signal. The fault detection system also includes a receiver and processor to receive each of the distinct transmissions from the plurality of self-powered wireless transducers and differentiate which self-powered wireless transducer produced each distinct transmission so as to determine a location of a fault detection, if one should occur.
In accordance with yet another aspect of the invention, a method of detecting vibration faults is disclosed which includes mounting a housing within a structure to be monitored so as to receive vibratory motion from the structure on at least a portion of the housing and converting power from vibratory motion to electrical energy within the housing as a result of receiving the vibratory motion. The method next includes storing the converted energy at least until the stored energy reaches a predetermined level, then activating an RF transmitter when the stored energy reaches the predetermined level, and then transmitting an RF signal indicative of vibrations in the structure which the housing is mounted in.
REFERENCES:
patent: 4237454 (1980-12-01), Meyer
patent: 4581572 (1986-04-01), Yoshiyuki et al.
patent: 4630465 (1986-12-01), Hatton
patent: 4642618 (1987-02-01), Johnson et al.
patent: 5212421 (1993-05-01), Hatton et al.
patent: 5791494 (1998-08-01), Meyer
patent: 5854994 (1998-12-01), Canada et al.
Kinsella James J.
McClanahan David L.
Taranowski Michael G.
Totten David S.
Eaton Corporation
Tong Nina
Ziolkowski Timothy J.
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