Radar-based method of level measurement

US5614911A · kind A · utility

Assignee

• Endress+Hauser Inc. · DE

Inventors

• Johanngeorg Otto · Aalen, DE
• Stefan Burger · Birkenfeld, DE
• Peter Gerst · Weil am Rhein, DE

Key dates

• Filing date: May 18, 1995
• Grant date: Mar 25, 1997
• Expiry date: May 18, 2015

Classification

• Technology area (CPC G): Physics
• CPC primary: G01S7/4039
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

In a method of level measurement on a radar basis, microwaves are emitted by means of an antenna to the surface of a material in a container and the echo waves reflected from the surface thereof are received. An actual echo function representing the echo amplitudes as a function of the distance is formed from the echo waves received by the antenna for each measurement, the probable useful echo and the transit time thereof are established from the actual echo function, and the distance of the material surface from the antenna is determined therefrom. To recognize the formation of a deposit and/or other trouble, such as e.g. damage to or loss of the antenna, an undisturbed echo function corresponding to an undisturbed measurement is obtained and stored prior to performing the measurements. In each measurement the actual echo function is compared to the stored undisturbed echo function. When due to the comparison, deviations between the two functions are found in the antenna region and the proximity zone, these deviations are evaluated to recognize the formation of a material deposit and/or other trouble.