Abstract: A water analysis device having a light source and a light detector for detecting an optical parameter of a water sample in a transparent measuring cell is disclosed. A ventilation circuit for ventilating a cell chamber is provided, wherein there is a differential pressure of at least 2.0 mbar between the cell chamber and the atmosphere when a ventilation pump is operated. The device housing forms the cell chamber which is fluidically sealed by a cover assembly. The cover assembly and the device housing have a mechanism that mimics the sealing action of a turn-lock fastener, such that the cover assembly can be secured to and/or released from the device housing by means of a rotational movement. The cover assembly and the device housing form an annular ring seal which is coaxial with the rotational movement and which is formed by an elastic sealing body having a circular sealing lip and a correspondingly circular shoulder seat on which the sealing lip is pressed due to the atmospheric differential pressure.

Abstract: A water analysis device having a light source and a light detector for detecting an optical parameter of a water sample in a transparent measuring cell is disclosed. A ventilation circuit for ventilating a cell chamber is provided, wherein there is a differential pressure of at least 2.0 mbar between the cell chamber and the atmosphere when a ventilation pump is operated. The device housing forms the cell chamber which is fluidically sealed by a cover assembly. The cover assembly and the device housing have a mechanism that mimics the sealing action of a turn-lock fastener, such that the cover assembly can be secured to and/or released from the device housing by means of a rotational movement. The cover assembly and the device housing form an annular ring seal which is coaxial with the rotational movement and which is formed by an elastic sealing body having a circular sealing lip and a correspondingly circular shoulder seat on which the sealing lip is pressed due to the atmospheric differential pressure.