The most important thing that decide how a mechanical seal works depend on the rotating and stationary seal faces. Seal faces are lapped so flat it is impossible for a liquid or gas to flow through them. This allows for a shaft to spin, while a seal is being maintained mechanically. What determines the amount of time a seal will last is selecting the right seal material combination for the application. Hard seal faces for abrasive service, Carbon Vs. Ceramic for simple water (or anti-freeze in the case of automotive applications). Carbon Vs. Silicon Carbide for most applications to reduce energy consumption and provide long life. For critical applications double mechanical seals are usually recommended.
Every other leak path within the mechanical seal is blocked with the use off a gasket, o-ring, wedge (Rubber, PTFE or Flexible Graphite). The other key aspect of a mechanical pump seal is how to maintain the seal. Springs (single or multiple), a metal bellows or just compressed elastomers are used to provide the needed energy to keep pressing the seal faces together. The load the seal faces receive are engineered into the design of the seal. The choice of what is the best depends on the temperature, and nature of what is being sealed (viscosity, abrasiveness, weight (is it a slurry?)).
Mechanical seals are engineered for most pumps, mixer and agitator applications in maintenance. In many cases the designs have been proven to be workhorses over years of use. In others seals must be designed for evolving industrial demands. The basic rotating face mechanical seal design is adaptable to serve a wide range of sealing applications including compressors. Standard mechanical seals can suit most requirements to temperatures of 500 degrees F and shaft speeds to 3600 RPM. The selection of secondary seal type often determines the temperature and chemical capabilities of the seal. The combination of materials used in the rotating and stationary faces define the abrasive resistance, and chemical resistance. Seal face combinations will also determine the amount of energy consumed by the pump, mixer, agitator or compressor. Seal faces can be balanced to permit higher pressure sealing. Balanced seals can seal pressures above 200 psi, or used in a multiple stages for higher pressures or especially severe fluid services. OEM mechanical seals can be furnished to meet the most demanding of industrial applications considering pressure, temperature, speed or fluid.
Post time: Oct-20-2022