According to different working conditions and medium properties, mechanical seals include high-temperature and low-temperature resistant mechanical seals, high-pressure and corrosion-resistant mechanical seals, particle resistant mechanical seals, and mechanical seals suitable for light hydrocarbon media that are prone to vaporization. Different structural types and materials of mechanical seals should be selected according to their different uses.

The main parameters for selection include: sealing chamber pressure (MPa), fluid temperature (℃), working speed (m/s), fluid characteristics, and effective space for installing seals.

The basic principles for selection are:

1. Determine whether the sealing structure adopts balanced or unbalanced type, single end face or double end face, etc. based on the pressure of the sealing chamber.

2. Determine whether to use rotary or static, fluid dynamic or non-contact type based on the working speed.

3. Determine the friction pair and auxiliary sealing materials based on temperature and fluid properties, as well as correctly select mechanical seal circulation protection systems such as lubrication, flushing, insulation, and cooling.

4. Determine whether to use multi spring, single spring, or wave spring, internal or external, based on the effective space for installing the seal.