Types of Double mechanical seals

Double mechanical seals can have seal faces arranged in three different ways, each with its own specific purpose.

1. Back-to-Back

2. Face-to-Face

3. Tandem

Back-to-Back

In this double seal configuration, two narrow seal faces are mounted back-to-back (opposing) to one another.

Face-to-Face 

Face-to-face seals can be used when the equipment is space constrained. In this configuration a portion of the seal is mounted in the seal chamber and the remainder is mounted outside of the seal chamber.

Tandem type

This configuration occurs when two sets of seal rings are identically orientated and mounted in-series. This configuration is often referred to as the “in-series seal face arrangement” or “face-to-back.” It is commonly used in dual seals.

What are the advantages of using a double mechanical seal? 

Compared to single mechanical seals, double mechanical seals provide more effective protection against leaks. If the primary seal fails, the secondary seal prevents any leakage into the atmosphere.

Although double seals may have a higher initial cost compared to single seals, their enhanced dependability and prolonged lifespan can eventually lead to reduced maintenance and replacement expenses while also prolonging the pump's lifespan.

Therefore, investing in double seals can be a cost-effective decision in the long run.