Method and device for liquid level measurement

• US 6,765,524 B2
• Filed: 02/04/2002
• Issued: 07/20/2004
• Est. Priority Date: 07/02/1999
• Status: Expired due to Term

• Current Assignee: Rosemount Tank Radar AB (Emerson Electric Company)
• Original Assignee: Saab Marine Electronics Aktiebolag (Emerson Electric Company)
• Inventors: Kleman, Mikael
• Primary Examiner(s): Pihulic, Daniel T.
• Application Number:
  US10/061,355
• Publication Number:
  US 20020135508A1
• Time in Patent Office: 897 Days
• Field of Search: 342/124, 732/90.R, 340/618
• US Class Current: 342/124
• CPC Class Codes: G01F 23/284 Electromagnetic waves
• CPC Class Codes: G01S 13/08 Systems for measuring distance only indirect measurement G01S13/46
• CPC Class Codes: G01S 13/88 Radar or analogous systems specially adapted for specific applications electromagnetic prospecting or detecting of objects, e.g. near-field detection, G01V3/00
• CPC Class Codes: G01S 7/352 Receivers

Abstract

A liquid level measuring gauging system including a radar antenna, a plurality of functionally independent radar measuring channels, and a feeder operably connected with the channels and operable to feed microwave signals of the channels to the antenna.

Claims

1. A liquid level measuring gauging system, comprising:

a radar antenna;

a plurality of functionally independent radar measuring channels; and

a feeder operably connected with the channels and operable to feed microwave signals of the channels to the antenna.

2. The system according to claim 1, wherein the feeder comprises a waveguide member for each channel.

3. The system according to claim 2, further comprising:

a plurality of transmission lines operable to feed microwave signals of the channels to the waveguide members of the feeder.

4. The system according to claim 3, wherein the transmission lines are galvanically isolated from the waveguide members.

5. The system according to claim 3, further comprising:

an electrically insulating washer for galvanically isolating the transmission lines from the waveguide members.

6. The system according to claim 2, further comprising:

microwave signal insulation between at least two of the waveguide members.

7. The system according to claim 2, wherein at least adjacent waveguide members are arranged orthogonally with respect to each other.

8. The system according to claim 1, further comprising:

a common waveguide outlet for all waveguide members, the common waveguide outlet being arranged at a waveguide interconnection.

9. The system according to claim 1, wherein the microwave signals are indistinguishable from each other.

10. The system according to claim 1, wherein the microwave signals are distinguishable from each other.

11. The system according to claim 1, comprising three channels.

12. The system according to claim 1, wherein one of the channels measures a maximum permitted level and one of the channels measures a level.

13. The system according to claim 12, wherein more than one channel measures a maximum permitted level.

14. The system according to claim 12, wherein more than one channel measures a level.

15. The system according to claim 1, wherein the channels are galvanically isolated from each other.

16. The system according to claim 1, further comprising:

coaxial connectors for connecting the channels to the feeder.

17. The system according to claim 1, wherein the radar antenna, radar measuring channels, and feeder are arranged in one aperture in a liquid holding tank.

18. A liquid level measuring gauging system, comprising:

a radar antenna;

a first radar measuring channel connected to the radar antenna and comprising a transmitter, a receiver and an indicating element; and

at least one further radar-measuring channel connected to the radar antenna, the radar waves of the further radar-measuring channel being distinguishable from the radar waves used in the first radar-measuring channel.

19. A liquid level measuring gauging system, comprising:

an antenna unit;

a feeder operable to feed at least two distinguishable microwave signals to the antenna unit, the feeder comprising at least two waveguide members, each waveguide member operable to receive one of the microwave signals of a transmission line;

a plurality of functionally independent channels operable to distribute the microwave signals;

a plurality of transmission lines operable to forward the microwave signals of the channels to the waveguide members of the feeder; and

a common waveguide outlet for all waveguide members, the common waveguide outlet being arranged at a waveguide interconnection.

20. An antenna feeder, comprising:

at least two waveguide members each operable to receive a microwave signal from a transmission line operable to forward the microwave signal of one of a plurality of functionally independent channels to the waveguide members; and

a common waveguide outlet for all waveguide members, the common waveguide outlet being arranged at a waveguide interconnection.

21. A method for measuring level in a receptacle, the method comprising:

distributing a plurality of distinguishable electromagnetic signals in separate channels;

feeding each signal to a separate waveguide member; and

transmitting the signals from each waveguide member to a common outlet.

22. A method for measuring a level in a receptacle using radar, the method comprising:

transmitting electromagnetic waves with radar measuring channels via a single aerial directed down into a receptacle, the waves being distinguishable by a detectable characteristic for each channel;

receiving a reflected time-delayed wave; and

calculating a level from the time delay.

23. The method according to claim 22, wherein the waves are distinguishable time-wise.

24. The method according to claim 22, wherein the waves are distinguishable by at least one of modulation and polarization.

25. The method according to claim 22, wherein the waves are used to execute redundant level measurements.

26. The method according to claim 22, wherein a level measurement is executed with one wave that produces a high level alarm.

27. A method in a level measuring gauging system for feeding at least two distinguishable microwave signals distributed in separated channels to a single antenna hardware, the method comprising:

providing a waveguide member for each microwave signal;

forwarding each microwave signal to an associated waveguide member through a transmission line associated with the signal;

galvanically isolating the transmission line from the associated waveguide member; and

transmitting the signals from each waveguide member via an outlet common for all waveguide members.

28. The method according to claim 27, further comprising:

galvanically isolating the channels from each other.