Metering system for liquid e.g. aqueous urea solution, has check valve that is arranged between throttle and suction side of metering pump

摘要

The system (10) has tank (12), a metering pump (16) and a metering valve (20). The discharge side of metering pump and metering valve are connected with each other through conduit (18), and a suction side of metering pump is connected through conduit (14) to tank. A return line (24) is provided to connect pressure side of the metering pump to suction side. A check valve (28) is arranged between a throttle (26) and suction side.