| 摘要 |
<p>The invention relates to a dosing pump unit for mixing a liquid reducing agent with an exhaust gas flow by means of a dosing pump (2) which is connected, on the input side thereof, to a connection connectable to a reducing agent tank (4) and, on the output side thereof, to a pressure pipe (16) and a pipe (10) for returning flow back to said reducing agent tank (4), wherein a non-return valve (20) which is prestressed against a hydraulic pressure produced by the dosing pump (2) is arranged in the pressure line (16), the return pipe (10) is connected to the pressure pipe (16) upstream of the non-return valve (20) in the reducing agent flow direction and a first stop valve (12) for selectively closing the return pipe (10) is placed therein.</p> |
