Device for detecting the quality of a liquid in a supply pipe

A method for connecting a device to a supply pipe, comprising:

• forming a through-bore in a wall of the supply pipe;
• fixing a closure means and then a flow cell of the device to the wall, in alignment with the through-bore, the flow cell including an inlet opening, an outlet opening, and at least one receiving device for the arrangement of at least one sensor, the inlet opening and the outlet opening provided on a base surface of the flow cell configured for connection to the supply pipe, the inlet opening of the flow cell connected to an intake pipe, a free end of the intake pipe configured for arrangement in the supply pipe, an adjustment means for the intake pipe is provided in the flow cell and said intake pipe being received displaceably in its longitudinal direction in the flow cell by the adjustment means or is configured to be adjustable in its length by the adjustment means, and the device includes a liquid pump connected to the intake pipe for a flow of the liquid in the supply pipe, the closure means provided for shutting off the flow of the liquid in the supply pipe in a direction towards the flow cell or away from the flow cell.