Linear-acting electric pump unit and method for operating said unit

A linear-acting electric pump, comprising:

• at least one electromagnet;
• and
• a pump unit driven by the at least one electromagnet;
• wherein the pump unit comprising at least two non-return valves;
• wherein the pump unit further comprising a single spring and a single bellows positioned between the at least two non-return valves and the single spring configured to move at least one non-return valve of the at least two non-return valves;
• and
• wherein fluid delivered by the pump unit flows through the at least one electromagnet and then enters the pump unit on a first side of the pump unit, and then flows through the at least two non-return valves each arranged on a same center line as the at least one electromagnet, and then exits the pump unit on a second side of the pump unit opposite the first side.