What Is The Difference Between Mechanical Seal And Oil Seal? Full-time Job

The mechanical seal is used in a pump, mixer and other mechanical engineering scenarios to contain the fluid within a vessel where a shaft rotates through a stationary (or rotating) housing.

Why is mechanical seal important in this situation? It is because the rotating shaft has to move in a wet environment, but there should not be the leakage of pressurized fluid. Hence, the role of a seal is quite critical.

Does it mean the seal stops the leakage completely? Well, on the practical grounds yes because there is no ‘visible leakage’.

There is a little leakage as the fluid vapors get released into the atmosphere from the faces of the seal, though. Since the quantity is hardly quantifiable, the seals are considered leak proof.

• Seals and gaskets are sometimes custom-made to service unique applications, but we can group most seals that prevent leakage at the interface of a moving part and a stationary part into eight main types of component mechanical seals.

  1. Wave Spring Mechanical Seals: Principally used for liquids of high viscosity, wave spring mechanical seals are popular for pharmaceutical, dairy, brewery and food processing applications. They are often fitted to the shaft with grub screws and in the case of high viscosity media would also have stationaries with anti-rotation pins. Some designs are specially constructed to work in shallow, confined seal housings.

  2. Double (or dual) mechanical seals are designed to ensure maximum sealing safety. These seals virtually eliminate leakage of the fluid or gas being handled in pumps or mixers.

     • Double seals provide a level of safety/zero emissions compliance not possible with single seals. This is essential when pumping or mixing a dangerous or toxic substance.

     • Double seals are a must-have for certain applications in many countries

     • These seals are increasingly used by companies to meet specific environmental goals or emissions requirements.Q: What is a cartridge seal?

       A: A cartridge-mounted, end-face mechanical seal (cartridge seal) is a completely self-contained unit that consists of the sealing components, a gland, sleeve, and hardware that allows the unit to be pre-assembled and preset. This feature eases installation and maintenance on rotating equipment on which axial adjustments are required.

       Q: What is a component seal?

       A: Component, end-face mechanical seals (a component seal) consist of a separate rotating member and stationary seat that mount in a gland or housing. Since they are not preset, installation and maintenance are generally more difficult requiring experienced technicians to properly install and adjust them.

       Q: What is an air seal?

       A: Air seals are non-contacting, pneumatic devices engineered for sealing rotating shafts. They protect against product loss, emissions, and contamination by using small amounts of air or inert gas that is throttled to create positive pressure and an effective seal.

       Metal Bellows

       A metal bellows is a precision-engineered, flexible metal component that acts as a leak-tight seal– effectively separating two environments from one another. These versatile parts can convert changes in pressure, temperature, and position into linear motion and be used for rotary transmission that maintains flexible mechanical and electrical connections.