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.

• The seals do not damage pump sleeve or shaft.

• Due to inboard springs that get adjusted as the seal faces wear, it is not required to do daily maintenance.

• Mechanical seals cause less power consumption than gland packing because of the lightly loaded faces.

• In mechanical seals, the lubricant doesn’t get washed out. Therefore, bearing contamination gets avoided in normal operational conditions.

• Plant equipment remains corrosion free.

• Relatively less maintenance and cleaning are required. It makes mechanical seals cost-effective.

• Oil seals prevent accumulation of dirt in the machine.

Oil seals close off the space between stationary and moving components in the mechanical equipment. It saves the lubricant from escaping through the equipment and ensures smooth operation of the machine.

Oil seals are called rotary shaft seal or radial lip also.

• Oil seals prevent seeping of potentially hazardous contaminants like dirt or fluid in the running machine

• These seals safeguard mixing of two things like oil and water

• In the high-intensity work environment, oil seals play a vital role

• Oil seals are long-lasting and sturdy

• Oil seals can work relentlessly if the preventive and corrective maintenance is in place

• Low wear and tear

Types Of Component Mechanical Seals

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. Water Pump Seals: Because water is such a poor lubricant of seal faces, it is critical that water pump seals use excellent materials for applications such as shower pumps, irrigation, heating systems, swimming pools and spas.

3. Bellows Mechanical Seals: Compact, versatile, extremely reliable seals suitable for a wide range of applications. Available with either O Ring Mounted or Boot mounted Stationaries in DIN and Non-Din sizes. Recommended for media containing solids and are widely used in Pumps, mixers, compressors etc.

4. Diaphragm Seals: Featuring parallel springs, diaphragm seals are used in very diverse applications including agitators, compressors, mixers, pumps and other rotary shaft equipment. . The diaphragm in the rotary head rotary seals on the shaft so they are not affected by rotational direction.

5. Balanced Diaphragm Seals: Similar to Diaphragm seals but are also hydraulically balanced to reduce heat and friction at the seal interface, an innovative patented design protects against seal failure in applications where thin metal drive components are prone to cut into the retainer.

6. Conical Mechanical Seals: This is an extremely versatile and popular mechanical seal. Available in a wide range of materials to suit a variety of environments, they are robust and durable. However these seals are rotation dependent and come with either left hand or right hand springs.

7. Parallel Mechanical Seals: Parallel seals are a heavy duty single spring seal. They can use different methods of providing the face to the seal and can be supplied with either left- or right-hand wound springs. A good general-purpose seal, they are used in marine pumps, waste-water, pulp and paper and textile applications as well as refrigeration compressors.

8. Multi Spring Seals: Proven effective design, PTFE wedge styles are often used in chemical the chemical industry for arduous applications such as corrosive process fluids.