Contacting shaft seal · Axial seal

Mechanical Seals

Two rings sliding against each other automatically establish a very narrow sealing gap, for particularly low leakage across nearly all fields of engineering.

Function & Design

Primary Ring & Mating Ring

The main components of the mechanical seal are two parts sliding against each other: the spring-loaded primary ring and a mating ring. One of the two rings is fixed in the housing (stationary), while the other ring is mounted on the rotating shaft. Contact pressure on the axial faces achieves the automatic adjustment of a very narrow sealing gap.

A leakage flow forms in the radial direction through the sealing gap. The gap height is varied by an axial relative movement of the sealing faces, which is why the term axial seal is also common for the mechanical seal. Thanks above all to their very low leakage, mechanical seals are used across all fields of engineering. Compared with stuffing box packings, they have a considerably narrower sealing gap and lower friction.

Very low leakage Narrow sealing gap Low friction
Mechanical seal with primary ring and mating ring
Applications

Where Mechanical Seals Seal

Mechanical seals are used in particular to seal pressure-loaded shaft passages. Process pumps in the chemical and petrochemical industries, machine tools, compressors, gearboxes, mixers and agitators are mostly sealed with mechanical seals.

When sealing environmentally hazardous liquids, mechanical seals are generally used on the product side.

Mechanical seal detail view
Downloads
Data sheet (DE) Data sheet (EN)
FAQ

Frequently asked questions

What is a mechanical seal?

A mechanical seal seals a rotating shaft via two rings sliding on each other: a spring-loaded primary ring and a mating ring. It automatically sets a very narrow sealing gap and thereby achieves particularly low leakage.

How does a mechanical seal work?

One ring is fixed in the housing, the other rotates with the shaft. An axial contact pressure on the faces creates a very narrow sealing gap; because the gap height varies axially, it is also called an axial seal.

Mechanical seal or stuffing box packing?

The mechanical seal has a much narrower sealing gap, lower friction and significantly lower leakage. The stuffing box packing is simpler and adjustable during operation but allows more leakage.

Where are mechanical seals used?

Mainly at pressure-loaded shaft passages: process pumps in the chemical and petrochemical industry, machine tools, compressors, gearboxes, mixers and agitators, as well as with environmentally hazardous media. All shaft seals at a glance.

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