How do mechanical seals work?

Tungsten Carbide seals for Waukesha Pumps

Posted by BestPump

January 26, 2025

How do mechanical seals work?

A mechanical seal in a pump is like a protective barrier that keeps everything where it’s supposed to be, much like making sure no cake batter spills out of a mixing bowl while the mixer is running.

In a pump, the rotating shaft spins like the mixer, while the pump housing stays still like the bowl. The mechanical seal has two key parts: one attached to the spinning shaft and the other fixed to the pump housing. These parts are pressed tightly together, with a thin film of liquid in between, acting like a tiny water slide. This film keeps the seal cool, reduces friction, and allows the parts to glide smoothly against each other.

Without the mechanical seal, the liquid being pumped could leak out, much like cake batter splashing everywhere. With the seal in place, the pump operates efficiently, safely, and without making a mess.

Analogy number 2

A mechanical seal in a pump works like a ziplock bag for liquids. Imagine you have a bag filled with water, and you want to keep the water inside while squeezing or moving it around. The ziplock seal keeps the water from leaking out, even if the bag is being handled or shaken.

In the pump, the mechanical seal does the same job. It sits around the rotating shaft (like the bag opening) and keeps the liquid inside, even though the shaft is spinning rapidly. A thin layer of liquid acts like a lubricant to keep the seal smooth and prevent wear, just like how a bit of air in the bag helps it seal properly. It’s a simple but clever way to keep everything contained and working efficiently!

Analogy number 3

A mechanical seal in a pump is like the rubber ring on a jar lid. Imagine you’re sealing a jar of jam. The rubber ring creates a tight seal between the jar and the lid, keeping everything inside even if you shake the jar or turn it upside down.

In a pump, the mechanical seal does the same thing. One part of the seal stays still, like the jar, while the other part moves, like twisting the lid. The seal keeps the liquid inside the pump while the shaft spins, ensuring nothing leaks out. A thin layer of liquid between the seal parts helps everything stay smooth and work efficiently, just like how the rubber ring on the jar stops wear and keeps it airtight.

You may also like…

Shear Sensitive Pumps

Shear Sensitive Pumps

Viking Pump Hygienic’s circumferential piston pumps handle high-value shear-sensitive liquids with gentle care. Keep...

Diaphragm Pump Trolley

Diaphragm Pump Trolley

Plastic Diaphragm Pump and Trolley This is one of the final Fluimac Phoenix air operated double diaphragm (AODD) pumps...

Chocolate Pumps

Chocolate Pumps

We're excited to announce our latest chocolate pumps innovation. Following years of experience in supporting clients...