How do Pump Seals Work?

How does Pump Mechanical seal Work?

Pump seals are essential in processes where the flow of liquid or gas has to be prevented from leaking.

The seal has two faces; one is stationary and another rotating. The faces are lapped so flat that the gas or liquid can’t flow through them.

It makes the shaft to spin freely.

How long will a seal last depend on what seal material is used? It also depends on the application.

In the case of critical applications, double mechanical seals are used.

  1. Basic components of pump seal

Essential components of a pump seal are rotating the shaft and stationary pump or mixer or seal-chamber housing.

Mechanical seals are rotating-face seals or end-face seals. In some designs, hybrid of lip-type seal or circumferential seals are used.

Regardless of the seal type you use, the following components are standard across all models:

  1. Rotating primary sealing element

The rotating primary sealing element is driven by the shaft to seal against the primary stationary sealing element. In some designs, it is fixed to the shaft.

  1. Stationary primary sealing element

It is fixed to the mixer, stationary housing of a pump or other component. The rotating shaft passes through it and seals against the rotating primary sealing element.

  1. Secondary seals (static or dynamic)

These seals act between the equipment shaft and housing and mechanical seal components.

Other than it, the closing force that biases the primary sealing element, which is in contact. It initiates sealing.

The sealing points

Typically, in a pump seal, there are four sealing points.

  • Primary seal that is between the stationary and the rotating faces.
  • Stationary seal that is between the stationary member and the gasket (stuffing box face).
  • Secondary seal that is between the rotatory member and the shaft sleeve (or shaft). It could be a wedge, v-ring, o-ring, or other sealing ring.
  • Seal that is between the stuffing box and gland plate. It could be an o-ring or gasket, depending on the application.

Among all the four seals, the primary sealing point which is between the stationary and rotating face, is most important one.

Both faces are pressed against each other using a spring force.  The mating faces are precision machined to make them flat. The measure of their flatness is a light band, which is an optical method.

The flatness of the faces is minimized to the degree that makes the leakage almost negligible. The initial face pressure is provided by spring compression.

Leak-Pack is ISO 9001:2008 certified company and one of the best mechanical seals exporters in India, providing solutions to all types of leakages by manufacturing Mechanical Seals and Sealing Components as per customer’s drawings, samples or requirements. To know more about Mechanical Seal call on +91-(2739) 271592 or email at

Also Read:

Why Use Mechanical Seals? Instead of Packing

How To Measure Mechanical Seal?

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