Mechanical seal is a device that help join system or mechanism by preventing leakage containing pressure or excluding contamination. Mechanical seal are design to provide greater sealing capability that cannot be achieve by traditional gland packing seal. Mechanical seals consist of sealing rings, friction pair ( one is fixed and the other is rotating) and backlash spring. Figure below shows the component.
Gland packing is a braided, rope like material that is packed around the shaft - physically stuffing the gap between the shaft and the pump housing. These packing were used widely in the industry as to reduce leakage. However, they are highly inefficient and require regular removal and maintenance. Mechanical seals are use to replace this unreliable sealing by minimise leakage and less replacement. Mechanical seals have a small gap between the faces with 1 micron (smaller than a strand of human hair). This features offer a small lubrication between the face and the leakage amount to be as little as half a teaspoon. As a result leak cases can be reduce significantly which results in higher production time and lower maintenance loss.