This chapter addresses sealing in pumps. The chapter begins with a discussion of O-rings, which are widely used as sealing elements in pumps.

The chapter then moves on to shaft sealing. Most pumps require sealing of the shaft where it penetrates the pump casing. The casing at the point of shaft penetration is subjected to either a positive pressure or a vacuum. Some pump types such as horizontal split case are sealed at both ends, while other types such as end suction have only one sealing point.