초록 ▼

The invention relates to a humidity sensor for capacitive measurement of the humidity contained in a material, predominantly a bulk product. For parallel operation of several humidity sensors, one individual humidity sensor has to fulfil particularly high requirements with regard to accuracy, sensit

The invention relates to a humidity sensor for capacitive measurement of the humidity contained in a material, predominantly a bulk product. For parallel operation of several humidity sensors, one individual humidity sensor has to fulfil particularly high requirements with regard to accuracy, sensitivity and interchangeability. These requirements are fulfilled by the humidity sensor as per the invention firstly in that at least one pole of a stray field condenser arranged in the humidity sensor is fitted as a conductive layer on the side of a closer plate in the casing of the humidity sensor which is turned away from the material or bulk product. Furthermore, there is arranged in the casing a digital arithmetic-logic unit which exhibits a calibration table stored in a digital memory for determination of humidity levels as a function of measurement signals in a capacity measurement circuit which measures the capacity of the stray field condenser and of interference values affecting the humidity sensor. A further increase in precision, finally, is achieved in that the capacity measurement circuit exhibits an amplitude stabilizer such that the voltage on the stray field condenser is constant over time.

대표청구항 ▼

[ We claim:] [1.] Humidity sensor for capacitive measurement of the humidity contained in a material, predominantly bulk products,comprising a casing which exhibits a non-conductive closer plate whose outer side is turned towards the material or bulk products or over which the material or bulk produ

[ We claim:] [1.] Humidity sensor for capacitive measurement of the humidity contained in a material, predominantly bulk products,comprising a casing which exhibits a non-conductive closer plate whose outer side is turned towards the material or bulk products or over which the material or bulk products travel, anda stray field condenser arranged in the casing for generation of an electrical stray field whose field lines penetrate the closer plate and the material or bulk products, whereinat least one pole of the stray field condenser is attached as a conductive layer on the side of the closer plate facing away from the material or bulk products.