Abstract: A device for a flow control of a liquid or gaseous medium, in particular for metering a fluid to be admixed into an exhaust gas treatment system, contains an electromagnet which has a solenoid coil with a magnetic core and an end-side magnetic plate in a magnet housing, and actuates a valve element in a valve compartment of a valve body to control a valve seat located there. The solenoid coil is protected against deformation with respect to the valve compartment, and is sealed using a sealing device.