Method and device for liquid level measurement by means of radar radiation

• US 6,414,625 B1
• Filed: 05/22/2000
• Issued: 07/02/2002
• 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:
  US09/576,544
• Time in Patent Office: 771 Days
• Field of Search: 342/124, 342/59, 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

The invention relates to a method and a device for measuring a level in a receptacle using radar. Via an aerial (1) directed down into the receptacle, an electromagnetic wave is transmitted and a reflected and time-delayed wave is received, the level being calculated from the time delay. Via one and the same aerial (1) at least two waves are transmitted and received, which are mutually distinguishable by a detectable characteristic for each wave. The device according to the invention is characterized in that connected to the aerial (1) is at least one further radar measuring channel (3; 4), the radar waves of which are mutually distinguishable and distinguishable from the radar wave used in a first radar measuring channel.

Claims

1. A method for measuring a level of a material in a receptacle, the method comprising:

producing electromagnetic waves with a plurality of measuring channels, the electromagnetic waves being distinguishable by a detectable characteristic for each channel;

transmitting the electromagnetic waves toward the material in the receptacle with a single antenna;

receiving a reflected time-delayed wave; and

calculating the level based upon the time delay.

2. The method according to claim 1, wherein the electromagnetic waves are distinguishable time-wise.

3. The method according to claim 1, wherein the electromagnetic waves are distinguishable by at least one of modulation and polarization.

4. The method according to claim 1, further comprising:

measuring the level with redundant electromagnetic waves.

5. The method according to claim 1, further comprising:

producing a high level alarm if a level of the material exceeds a target level.

6. A device for measuring a level of a material in a receptacle, the device comprising:

a first measuring channel and at least one further measuring channel, each measuring channel comprising a transmitter, a receiver and an indicator and being operable to produce electromagnetic waves distinguishable by a detectable characteristic for each channel; and

a single antenna connected to the first measuring channel and the second measuring channel and operable to transmit the electromagnetic waves toward the material and a time-delayed wave reflected by the material.

7. The device according to claim 6, wherein the at least one further measuring channel is redundant for another of the measuring channels.

8. The device according to claim 6, further comprising:

a second further measuring channel operable to measure and indicate a maximum permitted level.

9. The device according to claim 6, wherein the at least one further measuring channel is redundant for the first measuring channel, the device further comprising:

a second further measuring channel operable to measure a maximum permitted level.

10. The device according to claim 6, wherein the at least one further measuring channel is operable to measure the level, the device further comprising:

a second further measuring channel operable to measure a maximum permitted level.