Seals

Description

Function of Seals

The primary function of a compressor seal is to control or prevent unwanted leakage between adjacent components.

Seals may be used to:

• Reduce air leakage from the compressor
• Prevent lubricating oil from entering the compressed-air path
• Prevent air ingress into lubrication areas where applicable
• Separate process-air and oil environments
• Maintain required internal pressure conditions
• Protect bearings and lubrication systems
• Reduce contamination
• Support efficient compressor operation
• Maintain required clearances between rotating and stationary components

The specific sealing function depends on the location and type of seal.

Types of Seals Used in Centrifugal Compressors

Different sealing technologies may be used depending on compressor design and operating conditions.

Labyrinth Seals

Labyrinth seals use a series of precisely machined passages and clearances to restrict fluid flow between rotating and stationary components.

They are commonly associated with high-speed rotating machinery because they can provide non-contacting sealing without conventional rubbing surfaces.

Oil Seals

Oil seals are used to help retain lubricating oil within designated lubrication areas and reduce leakage around shafts or housings.

Mechanical Seals

Mechanical seals use controlled contact between sealing faces and may be used in specific auxiliary or lubrication-system applications depending on compressor design.

Carbon or Dry Gas Sealing Arrangements

Certain compressor configurations may use specialized non-contacting or carbon-based sealing systems. The actual arrangement depends on the compressor manufacturer and application.

O-Rings and Static Seals

O-rings and other static sealing elements may be used at covers, flanges, housings, fittings, and other stationary interfaces.

Shaft Seals

Shaft seals are particularly important where a rotating shaft passes through a stationary housing.

Depending on the compressor design, shaft sealing arrangements may help control:

• Compressed-air leakage
• Oil leakage
• Air migration
• Pressure differences between internal areas

The seal design must be compatible with the shaft speed, temperature, pressure, and required running clearance.

Labyrinth Seals in Centrifugal Compressors

Labyrinth seals are commonly used in high-speed rotating equipment because the sealing mechanism can operate with controlled clearances rather than continuous contact.

A labyrinth seal typically consists of carefully designed teeth, grooves, or passages that restrict fluid movement through a series of pressure drops.

Seal performance depends on factors such as:

• Radial clearance
• Axial geometry
• Shaft condition
• Seal tooth condition
• Pressure differential
• Rotor movement
• Installation accuracy

Excessive clearance can increase leakage, while insufficient clearance can increase the risk of rubbing.

Seals and Compressor Efficiency

Internal leakage reduces the amount of compressed air effectively delivered by the compressor.

Worn or damaged seals can increase leakage and may contribute to:

• Reduced compressor efficiency
• Increased power consumption
• Reduced capacity
• Higher operating temperatures
• Unstable operating conditions
• Increased maintenance requirements

Maintaining the correct seal condition and clearances is therefore an important part of compressor maintenance.

Seals in Lubrication Systems

Seals also play an important role in preventing lubricating oil from migrating into areas where it is not intended to be present.

Oil leakage can lead to:

• Lubricant loss
• Contamination
• Reduced oil pressure
• Increased maintenance requirements
• Potential damage to downstream components

The correct seal material and design must be compatible with the compressor lubricant and operating temperature.

Seal Construction and Materials

Seal materials depend on the type of seal and application.

Possible materials include:

• Carbon-based materials
• Stainless steel
• Alloy steels
• PTFE
• NBR
• EPDM
• Fluoroelastomers
• Graphite
• Engineered polymers
• Composite materials
• Other manufacturer-specific materials

Material selection should be based on the actual operating conditions and original compressor specification.

Common Seal Problems

Seals can deteriorate because of wear, incorrect clearances, contamination, vibration, temperature, or mechanical damage.

Common problems include:

• Excessive leakage
• Seal wear
• Seal rubbing
• Cracking
• Hardening
• Deformation
• Erosion
• Corrosion
• Damaged seal teeth
• Incorrect clearances
• Shaft surface damage
• O-ring deterioration
• Gasket failure
• Improper installation

The appropriate corrective action depends on the seal type and location.

Causes of Seal Failure

Excessive Clearance

Excessive running clearance can increase internal leakage and reduce sealing effectiveness.

Rotor Movement

Excessive shaft movement caused by bearing problems, imbalance, or other mechanical conditions can result in seal rubbing or damage.

Contamination

Particles or deposits can damage precision sealing surfaces and affect clearances.

Excessive Temperature

Operating temperatures outside the seal material’s specification can accelerate deterioration.

Incorrect Installation

Incorrect orientation, dimensions, alignment, or installation procedures can cause premature seal failure.

Shaft Damage

Grooves, scoring, corrosion, or excessive wear on the shaft can affect seal performance.

Lubrication Problems

For seals that require lubrication or are exposed to the lubrication system, incorrect lubricant conditions can contribute to deterioration.

Seal Inspection

During compressor maintenance and overhaul, seals should be inspected according to their location and design.

Inspection may include:

• Checking sealing surfaces
• Measuring clearances
• Inspecting labyrinth teeth
• Checking for rubbing marks
• Inspecting shaft surfaces
• Checking O-rings and elastomeric seals
• Inspecting for cracking
• Checking for erosion or corrosion
• Checking seal dimensions
• Inspecting mounting arrangements
• Checking rotor and bearing condition

Where required, dimensional inspection and non-destructive testing may be used.

Seal Clearance

Correct clearance is particularly important for non-contacting rotating seals.

Clearance that is too large may increase leakage, while clearance that is too small may increase the possibility of contact between rotating and stationary components.

The correct clearance must be determined from the compressor manufacturer’s design specifications and the actual operating conditions.

Seal Maintenance

Seal maintenance generally forms part of the compressor’s scheduled inspection or overhaul program.

Maintenance may include:

• Cleaning sealing areas
• Inspecting seal surfaces
• Measuring clearances
• Replacing damaged sealing elements
• Checking shaft condition
• Replacing O-rings and gaskets
• Verifying correct installation
• Inspecting associated bearings
• Checking for abnormal leakage after commissioning

Seal replacement should be accompanied by investigation of the original failure mechanism where applicable.

Replacement of Seals

A replacement seal should be matched to the exact compressor application.

Important selection parameters include:

• Compressor manufacturer
• Compressor model
• Compressor serial number
• Seal location
• Existing seal part number
• Seal type
• Shaft diameter
• Housing dimensions
• Seal dimensions
• Running clearance
• Operating pressure
• Operating temperature
• Shaft speed
• Lubricant compatibility
• Material
• Installation arrangement
• Rotation direction where applicable

A seal should not be selected solely by outside diameter or shaft diameter because the internal geometry and clearances can be compressor-specific.

Applications

Seals for centrifugal air compressors are used in industrial systems across industries including:

• Manufacturing plants
• Steel plants
• Cement plants
• Power plants
• Chemical industries
• Petrochemical facilities
• Refineries
• Pharmaceutical manufacturing
• Food and beverage industries
• Automotive manufacturing
• Textile industries
• Process industries
• Industrial compressed-air plants

Seal Selection Specifications

Why Choose Aegis Projects?

Aegis Projects Technology provides industrial compressor spare parts and replacement sealing components for centrifugal air compressor systems.

Our seal solutions can be evaluated according to the compressor’s original sealing arrangement, shaft dimensions, operating conditions, material requirements, and specified clearances.

We support requirements for:

• Centrifugal compressor seals
• Labyrinth seals
• Shaft seals
• Oil seals
• Mechanical seals
• O-rings
• Static sealing elements
• Seal assemblies
• Compressor overhaul seal kits
• Replacement and retrofit requirements

For accurate identification, share the compressor make, model, serial number, seal location, existing seal part number, photographs, shaft dimensions, seal dimensions, drawings, or compressor documentation wherever available.

Request a Quote

Looking for seals for a centrifugal air compressor?

Contact Aegis Projects Technology Pvt. Ltd. with your compressor and seal details. Our team can assist with identifying a suitable replacement seal or sealing assembly for your compressor application.