Patent ID: 8257070

Claim:
A seal apparatus of a gear pump, comprising: at least one pair of gears meshing with each other; a side plate arranged adjacent to the pair of gears; a housing sandwiching the side plate and arranged to be opposed to the pair of gears, at least one of the side plate and the housing comprising a shoulder portion; a seal member arranged between the housing and the side plate and arranged at the shoulder portion, the seal member separating a low pressure area from a high pressure area in a radial direction of one of the gears, the shoulder portion being located in the low pressure area, at least a part of the seal member facing the high pressure area; a backup member reinforcing the seal member and facing a tip portion of the shoulder portion; and a containing portion formed between a root portion of the shoulder portion and the seal member to contain a part of the seal member at least when the seal member is elastically deformed, wherein the seal member is substantially in a shape of a ring, wherein the low pressure area is separated from the high pressure area by using radially inside and outside areas of the ring-shaped seal member as the low pressure area and the high pressure area.