Priva Drain water sensor DSS

Description

The Priva Drain water sensor *(DSS) accurately measures the electrical conductivity (EC value) of the drain water and the quantity of drain water from the substrate. The Drain water sensor is connected to the process computer. Drain water is water that is not taken up by the plants and the substrate slabs. This excess of […]

The Priva Drain water sensor *(DSS) accurately measures the electrical conductivity (EC value) of the drain water and the quantity of drain water from the substrate. The Drain water sensor
is connected to the process computer. Drain water is water that is not taken up by the plants and the substrate slabs. This excess of irrigation water is necessary to prevent the substrate from
becoming excessively saline as a result of the accumulation of fertilisers.

EC measurement

The EC value is an indicator of the fertiliser-water ratio in the drain water: a high EC value points to a high concentration of fertilisers, while a low EC value points to a low concentration of fertilisers. The chemical composition of the drain water is determined by the selective uptake of the fertiliser elements by the plant roots. The desired EC value of the irrigation water depends on the crop, the substrate and the composition of the fertilisers. The EC sensor is located in the flow tube underneath the Drain water sensor. This tube is a trap construction, so that drain water is always present in the EC sensor.

Quantity measurement

Based on the quantity measurement of the Drain water sensor, the optimum strategy for supplying irrigation water is determined. The drain water derived from the substrate is collected in a drain trough (available separately). At the end of the drain trough, the drain water flows into the tray of the Drain water sensor. The water then flows, via a dirt filter, into the flow tube underneath the Drain water sensor. At the end of the tube, the drain water is collected drop by drop on the tipping ladle. When the ladle is full, it tilts downwards, thus activating a reed relay. The number of times that the tipping ladle tilts over is a measure of the quantity of drain water. The Drain water sensor has a maximum measuring capacity of 3.6 litres per hour.

These specifications are for the Drain water sensor 1 kΩ: