Device for monitoring the concentration of an air-vapor mixture

US4424703A · kind A · utility

Assignee

• Siemens Aktiengesellschaft · DE

Inventors

• Hans Winter · Gelnhausen, DE
• Eduard Mair · Munich, DE
• Holger Schoenewolf · Munich, DE

Key dates

• Filing date: Mar 22, 1982
• Grant date: Jan 10, 1984
• Expiry date: Mar 22, 2002

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T137/2509
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A device for monitoring the concentration of an air-vapor mixture in the fixing station of a non-mechanical printing or copying device has an ultrasonic transducer for generating and receiving an ultrasonic signal in the fixing station, the transit time of the ultrasonic signal between transmission and reception indicating the air-vapor mixture concentration in the station. The transit times are subdivided into at least three ranges of which the mean range or mean ranges identify a desired concentration. An evaluator circuit post-connected to the ultrasonic transducer forms signals corresponding to the ranges, the signals being entered in one of at least three status memories in accordance with their significance. The status memory which is filled first emits an output signal for triggering a corresponding reaction such as increasing the vapor density in the station, and cancels the contents of all of the status memories. False reactions as a result of brief and topically limited fluctuations from a mean concentration are thus largely avoided.