Abstract: A metering system for metering a liquid has an electric motor (32) for setting a desired feed rate, by modifying the rotation speed of the electric motor. It furthermore has an eccentric drive (52, 56), drivable by said electric motor (32), for a pump (53) that has two delivery directions. It also has a pump ring (62) made of an elastomeric material and a stationary ring (70) which is arranged relative to the pump ring (62) and to the eccentric drive (52, 56) in such a way that a pump chamber (120), extending in a circumferential direction, is formed between the stationary ring (70) and pump ring (62). The chamber changes shape upon rotation of the electric motor (32) in order to deliver a liquid to be metered through the pump chamber (120). A stationary seal (142) is provided in the pump chamber (120), between two fluid ports.

Abstract: A metering system for metering a liquid has an electric motor (32) for setting a desired feed rate by modifying the rotation speed of the electric motor. It furthermore has an eccentric drive (52, 56), drivable by said electric motor (32), for a pump (53) that has two delivery directions. It also has a pump ring (62) made of an elastomeric material and a stationary ring (70) which is arranged relative to the pump ring (62) and to the eccentric drive (52, 56) in such a way that a pump chamber (120), extending in a circumferential direction, is formed between the stationary ring (70) and pump ring (62), which chamber changes shape upon rotation of the electric motor (32) in order to deliver a liquid to be metered through the pump chamber (120). A stationary seal (142) is provided in the pump chamber (120), between two fluid ports.