Single vs. Double Mechanical Seals: What’s the Difference?

A mechanical seal is an essential component that pivots different parts together. They’re mostly used to fasten moving parts to the stationary ones. They eliminate spillage and leaks in the internal and external parts of a machine.

There are two main types of mechanical seal: single and double seals. Both are used to cater to a wide spectrum of applications. Essentially, they are designed to avert the fluid used by a machine from leaking into the external environment. Mechanical seals play a vital part in reducing environment contamination, enhancing energy savings, and boosting machine efficiency and safety.

Let’s delve deeper to understand the main differences between them.

Single Mechanical Seal

Single mechanical seals contain a spring that hold two layered surfaces known as faces, while sliding against each other. This layering is responsible to ensure smooth gliding using a thin film that reduces resistance and friction. A fluid film, acting as a lubrication, forms between the two flat sides, creating a barrier between the course gas and the air. This fluid film also decreases wear and tear of the two faces.

Double Mechanical Seal

A double mechanical seal has two layered seals: an essential and optional seal. The essential seal guarantees protection of the pump containments, whereas the detachable, auxiliary seal mitigates the risk of overabundance.

A double seal can be engineered in two ways:

Back to Back Arrangement

An engineered reactor mechanical seal by Robco

A double seal can contain two seal rings facing in the opposite direction. A barrier fluid is used as lubrication.

In case of a leak, the barrier penetrates the product and avoids spillage.

Face to Face Arrangement

A face to face double mechanical seal moves in opposite direction. This type of seal is a popular choice in the food industry to prevent food items from spilling. It works well in protecting sticky or hot substances by offering a barrier liquid that acts as a cooling agent for the seal.

Selecting a Mechanical Seal

When choosing a mechanical seal, you should keep three factors in mind:

  • Assess the characteristics of fluid that requires sealing. Some fluids turn to solid or gas state when their temperature alters, therefore, it’s important to choose a suitable mechanical seal.
  • Consider the temperature that can be handled by the seal. Some seals have a barrier that controls drastic temperature variations, making them suitable to protect hot fluids.
  • Not every seal is compatible with every type of fluid. Therefore, choose a type of mechanical seal like cartridge seals that doesn’t damage the pump shaft.

Quality Mechanical Seals and Services

Our team at Robco of America offers an extensive range of mechanical seals catering to all kinds of industrial and commercial application. Our mechanical seals variety includes custom designed seals, Cartridge Mechanical Seals, Assembly Seals, among many others.

Moreover, we also offer 24 hour emergency seal repair, onsite support, technical support, and custom engineering.

Call us at 800-662-0585 for more information.

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