How a mechanical seal works - continued.

The stationary element of the mechanical seal is indicated by “G” in the illustration. This element does not rotate with the pump shaft.

The mating surface between the rotating element and the stationary element is indicated by “F” in the illustration. This is the point where the sealing action is provided. The mating surfaces are actually constructed with a set of rings. These rings are highly polished, one is usually made of a hard material such as ceramic or steel. The other is usually made up of carbon. These rings are not shown in the illustration. The rotating element ring rotates, while pressing against the stationary element ring. The rotating element is kept pressed against the stationary element by a spring - which is also mounted on the shaft.

A spring is used to keep the rotating element pushed against the stationary element. The spring is indicated by “B” in the illustration. The spring extends from the location indicated by “B” to the side of the rotating element.

Point “E” in the illustration indicates how the stationary element of the seal is connected to the pump housing.