Mechanical seal unit

摘要

According to the present invention, the mechanical seal unit for pumps including a fixed seal ring (1) facing a lower pressure space and a rotatable seal ring (2) facing a higher pressure space (10), comprises: at least one outlet groove (12) disposed on a slidable seal face of the fixed seal ring (1) and open exclusively to the lower pressure space; and at least one inlet groove (11) disposed on a slidable seal face of the rotatable seal ring (2) and open exclusively to the higher pressure space (10) such that the inlet groove (11) and the outlet groove (12) partially meet to communicate with each other to form a fluid release passage at a certain point of rotation of the rotatable ring (2) relative to the fixed ring (1). Otherwise the outlet and inlet grooves may be disposed on the rotatable ring (2) and the fixed ring (1), respectively, to obtain the same effect. <IMAGE>