Feeding nodes - PU of various modifications are made on the basis of injectors with a nozzle diameter from 3 to 12 mm.
The PU consists of an inlet and an outlet of diam. 32, 40, 50, 63 mm separated by a valve or a tap. Between the inlet and outlet (parallel to the valve) an injector (jet pump) is mounted with a non-return valve or with a flow indicator IR (rotameter). At the inlet connection of the non-return valve or rotameter a PVC 12 mm tube is fitted that is connected to a container in which a mother liquor of fertilizers is prepared in advance.
As the flow passage decreases the valve closes the pressure between the inlet and outlet of the injector. At a pressure difference of 0.7 to 1.1 kg / cm2 the injector starts sucking the mother liquor of fertilizers which mixes well with water in the injector and enters the irrigation system as a feed solution. In this case, the greater the pressure difference between the inlet and outlet and the lower the outlet pressure, the more intensive the absorption.
Thus, by covering or slightly opening the valve it is possible to regulate the amount of fertilizers fed into the feed solution.
If the PU is equipped with an indicator of the flow rate of the IR the process of regulation and control is greatly simplified and the operational capabilities of the PU are increased. Now this device is not blind.