Why? Standard Centrifugal Pump

Leakage cannot be eliminated completely with any of these solutions and, in fact, it is important to maintain a small leakage to lubricate and cool the seal and pump shaft. In some cases, it is necessary to inject a lubricant to avoid overheating and this introduces the possibility of contamination of the pumped fluid.

• A soft packing material compressed around the pump shaft in a ‘stuffing box’ Packing material is held in place within the opening in the casing (the stuffing box) and compressed by a gland nut which can be progressively tightened as the packing material wears or settles .
• Lip seal or O-ring A rubber or plastic ring fits around the drive shaft and is held in place in a recess in the pump housing.
• Mechanical seal consists of two parts: a stationary component attached to the pump housing and a rotating component on the pump shaft. The faces of the two components are machined to be flat and smooth and are spring-loaded to keep them pressed together. This is the most effective option for reducing leaks but can be expensive and difficult to set up.