Self-powered wireless transducer
First Claim
1. A wireless transducer comprising:
- a housing adaptable to monitor an external physical condition of an external structure;
an 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, the power and characteristic signal having a characteristic of the external condition;
a transmitter mounted in the housing and connected to the energy conversion source to receive the power and characteristic signal and transmit a monitoring signal, the transmitter receiving power only from the energy conversion source as a source of power;
wherein the power and characteristic signal is an A.C. voltage signal and wherein the wireless transducer further comprises a rectifier circuit to rectify the A.C. power and characteristic signal;
an energy storage device and a energy level detector, the energy storage device is connected to the energy conversion source and the energy level detector is connected to the energy storage device, and wherein the energy storage device is capable of storing the rectified A.C. power and characteristic signal at least until the energy level detector detects a predetermined energy level; and
wherein the energy storage device is a capacitor, the capacitance of which is selected to set a pulse width of the monitoring signal such that a number of wireless transducers can each produce a unique monitoring signal, and the energy level detector comprises a voltage comparator having a hysteresis in which the monitoring signal is transmitted.
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Accused Products
Abstract
A self-powered wireless transducer is disclosed for monitoring external physical conditions, such as excessive vibrations in a bearing. The transducer includes an energy conversion source, such as a piezoelectric sensor to sense the external physical condition and create a power and characteristic signal that is used to power an RF transmitting circuit. A transmitter is provided to transmit signals indicative of the external physical condition, or changes in that physical condition, such as increased vibrations in a bearing to detect bearing faults before a breakdown. In this manner, the monitored machinery can be shutdown in an orderly manner and preventative maintenance can be completed. The self-powered wireless transducer includes an voltage storage device to receive electrical voltage from the piezoelectric sensor and a voltage detector to detect the level of voltage on the voltage storage device. Once the voltage detector detects a level of voltage at a predetermined level, an oscillating transmitting circuit is activated for a brief hysteresis period of the voltage detector. The information transmitted not only includes any fault detection, it also includes an address of the origin of the transmission.
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Citations
21 Claims
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1. A wireless transducer comprising:
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a housing adaptable to monitor an external physical condition of an external structure;
an 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, the power and characteristic signal having a characteristic of the external condition;
a transmitter mounted in the housing and connected to the energy conversion source to receive the power and characteristic signal and transmit a monitoring signal, the transmitter receiving power only from the energy conversion source as a source of power;
wherein the power and characteristic signal is an A.C. voltage signal and wherein the wireless transducer further comprises a rectifier circuit to rectify the A.C. power and characteristic signal;
an energy storage device and a energy level detector, the energy storage device is connected to the energy conversion source and the energy level detector is connected to the energy storage device, and wherein the energy storage device is capable of storing the rectified A.C. power and characteristic signal at least until the energy level detector detects a predetermined energy level; and
wherein the energy storage device is a capacitor, the capacitance of which is selected to set a pulse width of the monitoring signal such that a number of wireless transducers can each produce a unique monitoring signal, and the energy level detector comprises a voltage comparator having a hysteresis in which the monitoring signal is transmitted. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A fault detection system comprising:
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a plurality of self-powered wireless transducers, each comprising;
a housing adaptable to monitor an external physical condition of an external structure;
an 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, the power and characteristic signal having a characteristic of the external condition;
a transmitter mounted in the housing and connected to the energy conversion source to receive the power and characteristic signal and transmit a monitoring signal;
wherein each self-powered wireless transducer transmits a signal having a distinct address;
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;
an energy storage device and a energy level detector, the energy storage device is connected to the energy conversion source and the energy level detector is connected to the energy storage device, and wherein the energy storage device is capable of storing the power and characteristic signal at least until the energy level detector detects a predetermined energy level; and
wherein the energy storage device is a capacitor, the capacitance of which is selected to set a pulse width of the monitoring signal such that a number of wireless transducers can each produce a unique monitoring signal, and the energy level detector comprises a voltage comparator having a hysteresis in which the monitoring signal is transmitted. - View Dependent Claims (9)
a transmitter circuit containing the transmitter and connected to the energy storage device and the energy level detector, the transmitter circuit being activated when the energy level detector detects the predetermined energy level which thus activates the transmitter in response thereto.
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10. A method of detecting vibration faults comprising the steps of:
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mounting a housing on a structure to be monitored so as to receive vibratory motion from the structure on at least a portion of the housing;
converting power within the housing as a result of receiving the vibratory motion into electrical energy;
storing the converted electrical energy at least until the stored energy reaches a predetermined level;
using a singe piezoelectric sensor located in the housing for both sensing the vibratory motion and as a sole source of power generation;
activating an RF transmitter when the stored energy reaches the predetermined level; and
transmitting an RF signal indicative of a level of the sensed vibratory motion in the structure which the housing is mounted therein. - View Dependent Claims (11, 12, 13, 14)
receiving the RF signal at a remote location; and
processing the RF signal to determine a change in received vibratory motion in the structure being monitored.
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13. The method of claim 12 further comprising the steps of:
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displaying an indication of the RF transmitter'"'"'s identify; and
activating an alarm to indicate a fault condition.
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14. The method of claim 12 wherein the steps of processing the RF signal is further defined as comparing past RF signals to a present RF signal and if a present RF signal increases in frequency beyond a predetermined limit, then activating an alarm to indicate that vibratory motion has increased in the structure and that preventive maintenance is required.
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15. A wireless transducer comprising:
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a housing adaptable to monitor a vibratory movement of an external structure;
a single piezoelectric sensor mounted within the housing to sense the vibratory movement and provide a power and vibration level signal in response to the vibratory movement; and
a transmitter mounted in the housing and connected to the piezoelectric sensor to receive the power and vibration level signal and transmit a monitoring signal, the transmitter receiving power only from the piezoelectric sensor as a source of power. - View Dependent Claims (16, 17, 18, 19, 20, 21)
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Specification