Monitoring system for a mobile storage tank

• US 6,922,144 B2
• Filed: 10/17/2003
• Issued: 07/26/2005
• Est. Priority Date: 10/17/2003
• Status: Active Grant

• Current Assignee: Praxair Technology Incorporated (Linde Plc)
• Original Assignee: Praxair Technology Incorporated (Linde Plc)
• Inventors: Bulin, Tom, Langton, Gerard W., Gallagher, Tom, Gray, Scott E.
• Primary Examiner(s): Hofsass, Jeffrey
• Assistant Examiner(s): Bugg, George A.
• Application Number:
  US10/686,662
• Publication Number:
  US 20050083198A1
• Time in Patent Office: 648 Days
• Field of Search: 340/539.1, 340/539.22, 340/539.26, 340/603, 340612-614, 340/618, 340/438, 340/439, 340/825.36, 340/825.49
• US Class Current: 340/539.22
• CPC Class Codes: F17C 13/02 Special adaptations of indicating, measuring, or monitoring equipment measuring in general G01
• CPC Class Codes: F17C 2205/0326 electrically actuated
• CPC Class Codes: F17C 2221/011 Oxygen
• CPC Class Codes: F17C 2221/012 Hydrogen
• CPC Class Codes: F17C 2221/014 Nitrogen
• CPC Class Codes: F17C 2221/017 Helium
• CPC Class Codes: F17C 2223/0161 cryogenic, e.g. LNG, GNL, PLNG
• CPC Class Codes: F17C 2223/033 Small pressure, e.g. for liquefied gas
• CPC Class Codes: F17C 2250/034 using wireless transmissions
• CPC Class Codes: F17C 2250/0408 Level of content in the vessel
• CPC Class Codes: F17C 2250/043 Pressure
• CPC Class Codes: F17C 2250/0482 Acceleration
• CPC Class Codes: F17C 2250/072 Action when predefined value is reached
• CPC Class Codes: F17C 2270/0168 by vehicles
• CPC Class Codes: G08C 17/02 using a radio link
• CPC Class Codes: H04Q 2209/40 using a wireless architecture
• CPC Class Codes: H04Q 2209/883 where the sensing device enters an active or inactive mode
• CPC Class Codes: H04Q 9/00 Arrangements in telecontrol or telemetry systems for selectively calling a substation from a main station, in which substation desired apparatus is selected for applying a control signal thereto or for obtaining measured values therefrom
• CPC Class Codes: Y02E 60/32 Hydrogen storage

Abstract

A remote monitoring system for a mobile storage tank having a product container in which a remote telemetry unit gathers liquid level and head space pressure data and global position data. The remote telemetry unit effects a wireless transmission of a standard message structure containing the pressure and level data and the global position data. In addition, in case of a storage tank having a thermal shield fluid, pressure and level data for the shield fluid itself may also be in the standard data record as well as acceleration data from an accelerometer to indicate tank damage. If upset conditions of pressure and liquid level are reached in the thermal shield and/or product container, vapor may be vented in accordance with preset programming in order to attempt to reestablish liquid level and vapor pressure above set points.

Claims

1. A remote monitoring system for a mobile storage tank having a product container for storing a liquefied gas at cryogenic temperatures, said remote monitoring system comprising:

a sensor system to generate level signals referable to a liquid level of a liquid phase of said liquefied gas and pressure signals referable to vapor pressure of a vapor phase of said liquefied gas within said product container;

a global positioning system connected to said mobile storage tank to generate global position signals referable to a global position of said mobile storage tank in global latitude and longitude coordinates; and

a remote telemetry unit on board said mobile storage tank and responsive to said level signals, pressure signals and global position signals to store data records containing data referable to the liquid level and vapor pressure within said product container and the global latitude and longitude coordinates and to effect a wireless transmission of said data records and a unique remote telemetry unit identification in a standard message structure.

2. The remote monitoring system of claim 1, wherein:

said remote telemetry unit has a control program programmed to periodically activate said sensor system and said global positioning system and to store a plurality of said data records at predetermined time intervals and to effect said wireless transmission of said plurality of said data records after the storage thereof is complete; and

each of said data records contains time data indicative of a particular time interval in which said remote telemetry unit, said global positioning unit and said sensor system were activated.

3. The remote monitoring system of claim 2, further comprising:

an accelerometer to generate acceleration signals referable to a change in motion of said mobile storage tank;

said remote telemetry unit is response to said acceleration signals; and

said data records also comprise acceleration data referable to the change in motion of said mobile storage tank.

4. The remote monitoring system of claim 3, wherein:

said level signals, said pressure signals, and said acceleration signals are analog signals and said global position signals are in a digital format; and

said remote telemetry unit further has an analog to digital converter to convert said level signals, said pressure signals, and said acceleration signals to the level data, the pressure data and the acceleration data.

5. The remote monitoring system of claim 2, further comprising:

said mobile storage tank further having a cryogenic shield fluid contained within a shield fluid tank;

said sensor system being a first sensor unit;

a second sensor system to generate shield fluid level and shield fluid pressure signals referable to a cryogenic shield fluid liquid level and a shield fluid vapor pressure of said cryogenic shield fluid within said shield fluid tank; and

said remote telemetry unit is also responsive to said shield fluid level and shield fluid pressure signals and said data within said data records are also referable to the shield fluid level and the shield fluid pressure.

6. The remote monitoring system of claim 5, further comprising:

a remotely activated valve to respectively discharge shield fluid vapor from a thermal blanket configured to intercept radiant heat energy otherwise passing into said product container;

said remote telemetry unit having a controller to activate said remotely activated valve; and

said control program having pre-programmed setpoints of unacceptably high vapor pressure and low liquid level within said product container and at least one subroutine activated by the control program upon at least one of the vapor pressure and liquid level reaching at least one of the setpoints and deactivated by the control program when upon each of the vapor pressure being below the unacceptably high vapor pressure and the liquid level being above the unacceptably low liquid level;

the subroutine being responsive to the clock to intermittently signal said controller to activate at least said remotely activated valve to assume an open position and thereby allow shield fluid vapor to escape from said thermal blanket to be replaced by shield fluid liquid from said shield fluid tank.

7. The remote monitoring system of claim 6, wherein:

said remotely activated valve is a first remotely activated valve to discharge said shield fluid vapor from the thermal blanket;

a second remotely activated valve discharges vapor of said vapor phase;

the controller is configured to activate said first remotely activated valve and said second remotely activated valve; and

said at least one subroutine is a first subroutine to intermittently signal said controller to solely activate said first remotely activated valve and at least a second subroutine to intermittently signal said controller to activate said first remotely activated valve and said second remotely activated valve to assume said open position to respectively allow shield fluid vapor to escape from said thermal blanket to be replaced by shield fluid liquid from said shield fluid tank and said vapor of the vapor phase.

8. The remote monitoring system of claim 6 or claim 7, wherein:

said control program is programmed to continually store said plurality of said data records and to add additional of said data records thereto upon a communication failure and after a pre-programmed time interval to transmit said plurality of said data records and said addition data records added thereto.

9. The remote monitoring system of claim 8, further comprising:

an accelerometer to generate acceleration signals referable to a change in motion of said mobile storage tank;

said remote telemetry unit is response to said acceleration signals; and

said data records also comprise acceleration data referable to the change in motion of said mobile storage tank.

10. The remote monitoring system of claim 9, wherein:

said level signals, said pressure signals, and said acceleration signals are analog signals and said global position signals are in a digital format; and

said remote telemetry unit further has an analog to digital converter to convert said level signals, said pressure signals, and said acceleration signals to the level data, the pressure data and the acceleration data.

11. The remote monitoring system of claim 10 wherein said liquefied gas is helium and said shield fluid is nitrogen.