Monitoring Method and Apparatus Using Asynchronous, One-Way Transmission from Sensor to Base Station

• US 20080252475A1
• Filed: 10/02/2007
• Published: 10/16/2008
• Est. Priority Date: 10/04/2006
• Status: Active Grant

• Current Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Original Assignee: Space Adm, The Government Of The United States Of America, As Represented By The Secretary Of The Navy
• Inventors: Drouant, George J., Jensen, Scott L.
• Granted Patent: US 8,618,933 B2
• Time in Patent Office: Days
• US Class Current: 340/683
• CPC Class Codes: F16K 37/0083 by measuring valve parameters

Abstract

A monitoring system is disclosed, which includes a base station and at least one sensor unit that is separate from the base station. The sensor unit resides in a dormant state that uses no power, until it is awaked by the triggering of vibration-sensitive switch. Once awakened, the sensor may take a measurement, then transmit to the base station the measurement along with a time stamp of when the measurement was made. The sensor may optionally store the measured quantity and the time stamp for a particular length of time in a suitable storage device, such as with compact flash memory. The sensor transmits the measured quantity and the time stamp to the base station in an asynchronous manner. The transmission is initiated by the vibration-sensitive switch, not by the base station. The time stamp is encoded in a suitable manner, such as with an IRIG-B timing module. Once data is transmitted from the sensor to the base station, the sensor may return to its dormant state. Transmission between the sensor and the base station is one-way, so that the sensor does not receive any information from the base station. There may be multiple sensors for each base station, and the various sensors may optionally measure different quantities, such as current, voltage, single-axis and/or three-axis magnetic fields, that may correspond to physical quantities such as torsional strain, linear strain, temperature, ball valve cycles and linear voltage displacement transducer signals. The sensor may optionally include an energy harvester, such as a solar panel, for reducing and/or eliminating the drain on its battery.

Claims

1. A monitoring system, comprising:

a base station;

a first sensor separated from the base station and in wireless, one-way communication with the base station; and

a first vibration-sensitive switch for triggering the first sensor;

wherein the first sensor remains dormant unless triggered by the first vibration-sensitive switch; and

wherein upon being triggered by the first vibration-sensitive switch, the first sensor transmits a first measured quantity and a first time stamp to the base station.

2. The monitoring system of claim 1, wherein the first vibration-sensitive switch is a piezoelectronic laminate.

3. The monitoring system of claim 1, wherein the first vibration-sensitive switch uses no power when the first sensor is dormant.

4. The monitoring system of claim 1, wherein the base station records the first measured quantity and the first time stamp, and wherein the first time stamp corresponds to the time at which the first measured quantity is measured.

5. The monitoring system of claim 1, wherein after transmitting the first measured quantity and the first time stamp to the base station, the first sensor becomes dormant.

6. The monitoring system of claim 1, wherein the first vibration-sensitive switch is separate from the first sensor.

7. The monitoring system of claim 1, wherein the first vibration-sensitive switch is integral with the first sensor.

8. The monitoring system of claim 1, wherein the first sensor transmits along a line of sight within a radius of 250 feet.

9. The monitoring system of claim 1, wherein the first sensor transmits along a line of sight within a radius of 35 feet.

10. The monitoring system of claim 1, wherein the time stamp is encoded with an IRIG-B timing module.

11. The monitoring system of claim 1, wherein the first sensor fits within a clearance of 2 by 3 by 2 inches.

12. The monitoring system of claim 1, wherein the first measured quantity is a current signal.

13. The monitoring system of claim 1, wherein the first measured quantity is a voltage signal.

14. The monitoring system of claim 1, wherein the first measured quantity is a discrete digital signal.

15. The monitoring system of claim 1, wherein the first measured quantity is a single-axis magnetic field.

16. The monitoring system of claim 1, wherein the first measured quantity is a three-axis magnetic field.

17. The monitoring system of claim 1, wherein the first sensor includes a microprocessor, a transmitter, a regulator and a battery.

18. The monitoring system of claim 1, further comprising:

a second sensor separated from the base station and in wireless, one-way communication with the base station; and

a second vibration-sensitive switch for triggering the second sensor;

wherein the second sensor remains dormant unless triggered by the second vibration-sensitive switch; and

wherein upon being triggered by the second vibration-sensitive switch, the second sensor transmits a second measured quantity and a second time stamp to the base station.

19. The monitoring system of claim 18, wherein the base station includes a first microprocessor and a first receiver for the first sensor, and a second microprocessor and a second receiver for the second sensor.

20. The monitoring system of claim 1, wherein the sensor further includes an energy harvester.

21. A monitoring system, comprising:

a base station;

a sensor separated from the base station and in wireless, one-way communication with the base station; and

a piezoelectronic laminate vibration-sensitive switch for triggering the sensor;

wherein the sensor remains dormant unless triggered by the vibration-sensitive switch;

wherein upon being triggered by the vibration-sensitive switch, the sensor transmits a measured quantity and a time stamp to the base station; and

wherein the sensor measures at least one of a current signal, a voltage signal, a discrete digital signal, a single-axis magnetic field, and a three-axis magnetic field.

22. A method of monitoring a valve, comprising:

measuring a number of cryogenic cycles of the valve;

measuring a number of total cycles of the valve;

measuring an inlet temperature of the valve;

measuring an outlet temperature of the valve;

measuring a body temperature of the valve;

measuring a torsional strain of the valve;

measuring a linear strain of the valve;

measuring a preload position of the valve;

measuring a total travel of the valve;

measuring a total direction change of the valve; and

predicting a valve life in response to at least one of the number of cryogenic cycles, the number of total cycles, the inlet temperature, the outlet temperature, the body temperature, the torsional strain, the linear bonnet strain, the preload position, the total travel, and the total direction change of the valve.