Apparatus and method for determining the moisture of a sample
The disclosure relates to an apparatus for determining the moisture of a sample comprising a solid mixture, comprising at least one sample chamber for receiving the sample, at least one sensor for measuring a characteristic of a gas mixture surrounding the sample and a determination device for determining the moisture of the sample from the at least one characteristic. According to the disclosure, provision is made for the apparatus to comprise an measurement chamber which may be evacuated and which, in terms of flow, is selectively separable from the at least one sample chamber or connectable to the sample chamber, wherein the at least one sensor is configured to measure the characteristic of the gas mixture in the measurement chamber. The disclosure furthermore relates to a corresponding method for determining the moisture of a sample comprising a solid mixture.
1. An apparatus for determining the moisture content of a sample which comprises a solid mixture, comprising:
at least one sample chamber for receiving the sample;
at least one sensor for measuring a characteristic of a gas mixture surrounding the sample;
a determination device for determining the moisture content of the sample from the at least one characteristic; and
a measuring chamber wherein the at least one sensor is configured to measure the characteristic of the gas mixture in the measuring chamber;
at least one shut-off fitting configured to selectively fluidically disconnect the measuring chamber from or connect the measuring chamber to the at least one sample chamber; and
a pump for evacuating the measuring chamber.
2. The apparatus according to claim 1 , further comprising at least one heater for heating the sample in the at least one sample chamber.
3. The apparatus according to claim 1 , wherein the pump is adapted for evacuating the measuring chamber in the range of 10 hPa residual gas pressure or less.
4. The apparatus according to claim 1 , wherein a plurality of sensors are provided.
5. The apparatus according to claim 1 , wherein the sensor or at least one of the sensors is a dew point sensor.
6. The apparatus according to claim 5 , wherein the dew point sensor determines the water vapour partial pressure by means of a capacitive sensor element.
7. The apparatus according to claim 1 , further comprising a measuring, control and/or regulating apparatus which forms the determination device and is signal technically connected to the at least one sensor.
8. The apparatus according to claim 1 , further comprising at least one fluid circulation system, in which the measuring chamber is fluidically interconnected.
9. The apparatus according to claim 8 , wherein the at least one sample chamber, too, is selectively interconnectable or permanently interconnected in the at least one fluid circulation system.
10. The apparatus according to claim 1 , wherein this apparatus is configured as a mobile moisture meter, in particular as a portable moisture meter.
11. A method for determining the moisture content of a sample which comprises a solid mixture, comprising the following steps:
providing the sample in a sample chamber;
evacuating a measuring chamber;
measuring a characteristic of a gas mixture surrounding the sample, wherein the measurement is carried out in the measuring chamber after the measuring chamber being fluidically connected to the at least one sample chamber, wherein the gas mixture surrounding the sample forms beforehand in the sample chamber which is fluidically separated from the measuring chamber; and
determining the moisture content of the sample from the at least one characteristic.
12. The method according to claim 11 , wherein the residual gas pressure of the measuring chamber in the evacuated state is in the range of 10 hPa or less.