Dosing pump unit

A metering pump assembly for blending a fluid reduction agent into an exhaust gas stream. Refers to a metering pump assembly for mixing a fluid reducing agent in an exhaust gas stream with a metering pump (2) to deliver the reducing agent and with a premixing device (39) (18), the reducing agent delivered by the metering pump (2) and mixed with a pressurized gas, characterized in that the metering pump assembly comprises a pump head with a plate (40) in which at least the metering pump (2) and the premixing device (39) are arranged (fig. 8).