What Are Mechanical Seals & What Do They Do?

Mechanical seals are used to ensure maximum sealing safety by encircling stationary and rotary parts of a machine. Mechanical seals come in two varieties: debris-type, which is commonly found in sanitary systems, and metal-to-metal type mechanical seals which are located in rotating shafts.

What are mechanical seals?

A mechanical seal is a device that helps join two or more moving parts in an engine or other machine. The seal prevents fluid or gas from escaping between the parts. Mechanical seals are used in many different applications, including automotive, aerospace, and industrial machinery. There are many different types of mechanical seals, each designed for a specific application.

Types of mechanical seals

There are three main types of mechanical seals: single spring, cartridge, and pusher. 

Single spring: A single spring is the most common type of seal. It consists of a metal bellow that expands and contracts as the shaft moves up and down. The movement of the bellows creates a seal between the shaft and the housing. 

Cartridge: A cartridge seal is similar to a single spring seal, but it has two metal bellows. The two bellows allow for more flexibility and provide a better seal than a single spring seal. 

Pusher: A pusher seal is used in applications where there is high pressure or high temperatures. The pusher seal has a metal ring that sits on top of the shaft. The ring is pushed by the pressure of the fluid to create a seal between the shaft and the housing.

Installation tips for stationary parts sealing

If you are installing stationary parts sealing, there are a few tips to keep in mind to ensure a proper installation. First, make sure the components of the seal are clean and free of debris. Any dirt or grit can damage the seal and cause it to fail.

Next, be sure to properly lubricate the seal before installation. This will help protect it from wear and tear. If possible, use a high-quality synthetic grease designed for seals.

Finally, take care when tightening the bolts that hold the seal in place. Too much force can damage the seal, so follow the manufacturer’s instructions carefully. With these tips in mind, your mechanical seal should give you years of trouble-free service.

Maintenance guidelines for a mechanical seal

Assuming you are discussing a typical centrifugal pump mechanical seal, the following are suggested maintenance guidelines: 

-Regularly inspect the condition of the sealing faces and other parts of the seal. If any damage is found, replace the seal immediately.

-Inspect the condition of the O-rings and other seals. If any damage is found, replace the O-rings or other seals immediately.

-Check the alignment of the shaft and pump housing. If they are not properly aligned, realign them according to the manufacturer’s instructions.

-Make sure that there is no dirt or debris on the sealing surfaces. If there is, clean them off with a soft cloth or brush.

-Check that all bolts and screws are tight. If any are loose, tighten them according to the manufacturer’s instructions.


In conclusion, mechanical seals are an important component in many different types of machinery. They help to seal off fluids and prevent them from leaking out. There are many different types of mechanical seals available on the market, so it is important to choose the right one for your needs. With so many options available, it is easy to find a seal that will work perfectly for your application.