Patent attributes
A pump includes: a stator (4), a rotor (6) slidably and rotatably mounted at least partially in the stator, the rotor comprising a first axial extension (24) having a first diameter (D1) and a second axial extension (26) having a second diameter (D2) greater than the first diameter, a first valve (V1) formed by a first valve seal (18) mounted on the stator around the first axial extension, in conjunction with a first channel (42) in the rotor that is configured to allow liquid communication across the first valve seal when the first valve is in an open position, a second valve (V2) formed by a second valve seal (20) mounted on the stator around the second axial extension, in conjunction with a second channel (44) in the rotor that is configured to allow liquid communication across the second valve seal when the second valve is in an open position; a pump chamber (8) formed between the rotor (6) and stator (4) and between the first valve seal (18) and second valve seal (20); and a pump chamber seal (22) circumscribing the rotor second axial extension and separating the pump chamber (8) from an external environment. The stator (4) further comprises a dead-zone seal section (40) surrounding a dead-zone volume (39) formed between the rotor second axial extension (26) and the stator (4), wherein the dead-zone seal section (40) comprises axially extending portions (58) connected to upper and lower radial portions (60,60′) to form a closed sealing circuit.
