Laser measurement of liquid level in a holder

• US 7,082,828 B1
• Filed: 03/12/2004
• Issued: 08/01/2006
• Est. Priority Date: 01/29/2002
• Status: Expired due to Fees

• Current Assignee: Electromechanical Research Laboratories, Inc.
• Original Assignee: Electromechanical Research Laboratories, Inc.
• Inventors: Wilkins, Larry C.
• Primary Examiner(s): Williams, Hezron
• Assistant Examiner(s): BELLAMY, TAMIKO D
• Application Number:
  US10/799,221
• Time in Patent Office: 872 Days
• Field of Search: 733/13, 733/14, 733/19, 732/93, 732/90.V, 250/577, 342/124, 367/908, 337/19
• US Class Current: 73/313
• CPC Class Codes: B63B 25/082 Arrangements for minimizing pollution by accidents associated with tanks for fuel or the like not forming bunkers B63B17/0036

Abstract

Leakage detection of cargo from the hold of a barge involves a mounting plate to the top hatch of the hold. Two pipes secured to the plate extend to locations near the bottom. Each pipe has a guide tube in it coaxial with the pipe. Each pipe has a float in it received around the guide tube. A float follower is in each tube and magnetically coupled to the float so that the float follower rises and falls with the float. One pipe has an open bottom for cargo to freely move up and down in the pipe as the hold is filled and emptied. The other pipe has a valve at the bottom for admitting cargo from the hold to the pipe at the port of origin of the vessel. Following loading of the cargo, the valve is closed. One embodiment tethers the floats to reels atop the plate. Any change of level of the floats, reflecting a loss of cargo during transit from the port of origin to that of destination, is reflected in relative rotation of the reels and triggering an output signal to an annunciator. Another embodiment employs lasers transmitting to and receiving from the float followers, reporting to a comparator producing an output signal to an annunciator upon recognition of a difference between distances indicated by laser output signals. A third embodiment eliminates the guide tubes, floats and float followers. Portable embodiments for measurement of liquid levels alone, and also useful for loss detection, include a carrier handle for hand carrying the measuring laser and computer from one tank to another in a multiple tank site or transporter to measure liquid levels in a number of tanks. Other embodiments include a portable combination ultrasonic measurement with laser measurement to indicate temperature in the atmosphere of the liquid level, along with indication of the level measurements.

Claims

1. Liquid level measurement apparatus for liquid in a holder and comprising:

a holder for containing liquid;

a vertical pipe secured to said holder, said pipe being arranged for at least partial submersion in said liquid;

a target in said pipe and arranged to rise and fall in synchronism with rise and fall of the surface of liquid in said holder;

a laser for transmitting signals longitudinally in the pipe to impinge on said target in the pipe to be reflected by said target back to said laser;

a computer coupled to said laser to compare time of transmission of said signals by said laser, with time of reception by said laser of said signals reflected back by said target, and determine the level of the surface of said liquid in said holder;

a signal transmission tube coupled to said laser for said signals transmitted by said laser into said pipe;

said pipe having a receiver arranged to receive said transmission tube for providing a passageway for signals produced by said laser, from said laser through said pipe to said target and for return of said laser signals reflected by said target, from said target to said laser;

said signal transmission tube and said receiver are configured to mate for establishing collinear axes of said transmission tube and said pipe for transmission of signals produced by said laser on said axis, from said laser to said target; and

said transmission tube and said receiver are configured to mate by sliding said tube and said receiver together.

2. The apparatus of claim 1 and wherein:

said transmission tube has a lower end and an upper end; and

said receiver has all upwardly opening socket to receive a portion of said tube adjacent said lower end of said tube to facilitate coupling said carrier to said pipe for transmission and reception of said laser signals, and for de-coupling said carrier from said pipe for transporting to another liquid holder.

3. Liquid level measurement apparatus for liquid in a holder and comprising:

a holder for containing liquid;

a vertical pipe secured to said holder, said pipe being arranged for at least partial submersion in said liquid;

a target in said pipe and arranged to rise and fall in synchronism with rise and fall of the surface of liquid in said holder;

a laser for transmitting signals longitudinally in the pipe to impinge on said target in the pipe to be reflected by said target back to said laser;

a computer coupled to said laser to compare time of transmission of said signals by said laser, with time of reception by said laser of said signals reflected back by said target, and determine the level of the surface of said liquid in said holder;

a signal transmission tube coupled to said laser for said signals transmitted by said laser into said pipe;

said pipe having a receiver arranged to receive said transmission tube for providing a passageway for signals produced by said laser, from said laser through said pipe to said target and for return of said laser signals reflected by said target, from said target to said laser;

a carrier coupled to said laser for lifting said laser from said receiver on said liquid holder following measurement of the level of the surface of liquid in said holder, and for carrying said laser to a receiver like said first-mentioned receiver but located on another liquid holder to measure the level of the surface of a liquid in said another liquid holder; and

a pipe cover pivotally mounted to said holder to pivot from a first, receiver-covering orientation, to a second orientation enabling access to said receiver for receiving said transmission tube.

4. The apparatus of claim 3 and further comprising:

a code on the inside of said cover for identifying the holder to which said cover is mounted; and

a code reader mounted to said carrier for reading said code when said transmission tube is received in said receiver.

5. The apparatus of claim 4 and further comprising:

a stop on said carrier and positioned to support said cover in position for reading said code by said code reader when said transmission tube is received by said receiver.

6. Liquid level measurement apparatus for liquid in a holder and comprising:

a holder for containing liquid;

a vertical pipe secured to said holder, said pipe being arranged for at least partial submersion in said liquid;

a target in said pipe and arranged to rise and fall in synchronism with rise and fall of the surface of liquid in said holder;

a laser for transmitting signals longitudinally in the pipe to impinge on said target in the pipe to be reflected by said target back to said laser;

a computer coupled to said laser to compare time of transmission of said signals by said laser, with time of reception by said laser of said signals reflected back by said target and determine the level of the surface of said liquid in said holder;

a signal transmission tube coupled to said laser for said signals transmitted by said laser into said pipe;

said pipe having a receiver arranged to receive said transmission tube for providing a passageway for signals produced by said laser, from said laser through said pipe to said target and for return of said laser signals reflected by said target, from said target to said laser;

an ultrasonic signal transducer;

a second signal transmission tube, said second tube being coupled to said ultrasonic signal transducer, and

said second tube being receivable by said receiver for providing a passageway for ultrasonic signals produced by said transducer, from said transducer through said pipe to said target and for return of said ultrasonic signals reflected by said target, from said target to said transducer.

7. The apparatus of claim 6 and wherein:

said computer is coupled to said transducer to compare time of transmission of said ultrasonic signals by said transducer with time of receipt by said transducer of said ultrasonic signals reflected from said target to provide a measurement representative of the level of the surface of the liquid in the holder, and compare the level measured by the laser to the level as indicated by the transducer, and apply a temperature compensation factor to the level measurement by the transducer to match the level measurement by the laser, and output the temperature corresponding to said compensation factor that achieves the match.

8. The apparatus of claim 7 and further comprising:

a display representing measurement of the level of the surface of the liquid in the holder and the temperature of said atmosphere.

9. The apparatus of claim 7 and further comprising:

a second vertical pipe secured to said holder, said second pipe being arranged for at least partial submersion in said liquid;

a second target, said second target being located in said second pipe and arranged to rise and fall in synchronism with rise and fill of the surface of the liquid in said holder;

said second pipe having a receiver to receive said second signal transmission tube for providing a passageway for signals produced by said transducer, from said transducer to said second target, and for return of said transducer signals reflected by said target, from said target to said transducer.

10. The apparatus of claim 6 and wherein:

said transducer is mounted atop said second signal transmission tube.

11. Liquid level measurement apparatus for liquid in a holder and comprising:

a holder for containing liquid;

a vertical pipe secured to said holder, said pipe being arranged for at least partial submersion in said liquid;

a target in said pipe and arranged to rise and fall in synchronism with rise and fall of the surface of liquid in said holder;

a laser for transmitting signals longitudinally in the pipe to impinge on said target in the pipe to be reflected by said target back to said laser;

a computer coupled to said laser to compare time of transmission of said signals by said laser, with time of reception by said laser of said signals reflected back by said target, and determine the level of the surface of said liquid in said holder;

an ultrasonic transducer coupled to said signal transmission tube and oriented to project ultrasonic signals down through the tube and pipe and receive ultrasonic radiation up through the pipe; and

wherein;

said laser is oriented to transmit signals horizontally through an opening in said pipe;

a reflector is provided on said pipe and oriented to reflect laser signals received horizontally and transmit said signals vertically down through said pipe, and receive signals reflected from said target up through the pipe and reflect the signals horizontally into the said laser; and

wherein

said computer is coupled to said transducer to compare time of transmission of said ultrasonic signals by said transducer with time of receipt by said transducer of said ultrasonic signals reflected from said target to provide a measurement representative of the level of the surface of the liquid in the holder, and compare the level measured by the laser to the level represented by the transducer measurement, and apply a temperature compensation factor to the level measurement by the transducer to match the level measurement by the laser, and output the temperature corresponding to said compensation factor that achieves the match.

12. The apparatus of claim 11 and wherein:

said reflector projects into said pipe from a side wall of said pipe and has a laser reflecting surface disposed at about 45 degrees from the path of a beam from the laser to reflect the laser beam downward along the axis of the pipe.

13. The apparatus of claim 11 and wherein:

said reflector is pivotally mounted to the wall of said pipe and is received in a recess in said wall for facilitating ultrasonic transmission of signals along the axis of said pipe, and wherein;

said reflector is pivotal into said pipe to a position disposed at about 45 degrees from the path of a beam from the laser to reflect the laser beam downward along said axis of said pipe.

14. The apparatus of claim 11 and wherein:

said reflector is pivotally mounted in the pipe for orientation of a reflecting surface of the reflector from a plane containing the axis of the pipe to a plane at a 45 degree angle to said plane to reflect a beam from the laser downward along the axis.