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Low-CTE Resin Labyrinth Seal for Turbo Compressors
Balancing clearance design flexibility and sealing performance with ALP K03-406
Clearance design is critical to labyrinth seal performance
In turbo compressors, labyrinth seals help reduce gas leakage inside the machine and support stable compression efficiency. To improve sealing performance, the clearance between the rotor or shaft and the seal component must be designed as small and stable as possible.
When clearance is too small
A smaller clearance can improve sealing performance, but it can also increase the risk of contact between the seal and the rotor or shaft during operation.
- Contact caused by thermal expansion or dimensional change
- Damage to the rotor or mating shaft
- Unexpected shutdowns or maintenance work
When clearance is too wide
A larger clearance can reduce contact risk, but it also increases the leakage path through the seal area. This may lead to lower sealing performance and reduced compressor efficiency.
- Increased gas leakage
- Lower sealing performance
- Potential impact on operating efficiency
ALP K03-406: Thermal Expansion Close to Stainless Steel
General resin materials tend to have a higher coefficient of thermal expansion than metals. ALP K03-406 is designed to reduce dimensional change caused by temperature variation, making it easier to consider clearance designs closer to metal seal concepts.
Coefficient of Thermal Expansion
Unit: ×10⁻⁶/°C ｜ Temperature range: 23–140°C
Values shown are representative and not guaranteed. Actual applicability must be reviewed according to operating conditions and product geometry.
Designed to support stable clearance
ALP K03-406 has a coefficient of thermal expansion close to stainless steel. By reducing the difference in thermal expansion between resin and metal components, it helps support more stable clearance design.
This makes it possible to consider resin labyrinth seals where both leakage reduction and lower counterface attack are required.
Key benefits of ALP K03-406 resin labyrinth seals
ALP K03-406 combines low thermal expansion with the advantages of resin materials. It supports seal designs that consider leakage reduction, compressor efficiency, protection of the mating shaft, and corrosion resistance.
Greater Flexibility in Clearance Design
Reduced dimensional change makes it easier to consider smaller seal clearance during operation.
Support for Reduced Gas Leakage
Smaller leakage paths can contribute to improved sealing performance.
Supporting Compressor Efficiency
Lower internal leakage helps maintain compression performance and operating efficiency.
Reduced Risk of Damage to Mating Shafts
Resin materials can help reduce damage to mating surfaces compared with metal seals.
Corrosion resistance
Resin material properties can be used in environments where metal corrosion is a concern.
Application to turbo compressor labyrinth seals
A labyrinth seal is a non-contact seal that restricts gas flow by creating a complex leakage path between the rotating shaft and the stationary seal component. Because the seal is used without direct contact during normal operation, clearance control is directly linked to sealing performance.
Labyrinth seal applications
ALP K03-406 can be considered for resin labyrinth seals where clearance stability, leakage reduction, and counterface protection must be reviewed together.
Abradable seal concepts
Resin materials can also be considered for abradable seal concepts, where the seal material is designed to wear preferentially in the event of contact.
Large-diameter seal components
Starlite combines material design, molding, machining, and evaluation expertise to consider large-diameter resin seal components for compressor applications.
Comparison with metal and general resin seals
The table below summarizes the relative positioning of metal seals, general resin seals, and ALP K03-406 resin seals for turbo compressor sealing applications.
| Item | Metal seal | General resin seal | ALP K03-406 resin seal |
|---|---|---|---|
| Coefficient of thermal expansion | Low | High | Close to stainless steel |
| Clearance design | Easy to design with narrow clearance | Wider clearance may be required to account for thermal expansion | Easier to consider smaller clearance than with general resin |
| Risk of damage to mating shaft | Concern in contact events | Generally lower than metal | Lower counterface attack can be expected as a resin material |
| Corrosion resistance | May be an issue depending on the gas and environment | Can use resin material properties | Can be considered where metal corrosion is a concern |
| Sealing performance | Can be designed for high sealing performance | May be limited by thermal expansion and clearance requirements | Supports smaller clearance design and leakage reduction |
| Long-term operation | Depends on operating conditions and contact risk | Dimensional change can be a concern | Contributes to stable operation by combining dimensional stability and resin properties |
This comparison is intended as a general guide. Final material selection must be reviewed based on gas type, temperature, pressure, rotation speed, mating material, seal geometry, and required leakage performance.
Material design expertise built through gas compressor seal applications
STARLITE ALP is a PTFE-based high-performance sliding material engineered with Starlite’s proprietary material design technology. By leveraging low friction, heat resistance, chemical resistance, and wear resistance, ALP has been used in various seal and sliding components for large reciprocating gas compressors.
Typical ALP applications
- Piston rings
- Rider rings
- Rod packings
- Seal rings
- Sliding components
Design factors for gas compressor seals
Seal materials for gas compressor applications must be selected by considering gas type, pressure, temperature, sliding conditions, mating material, and required leakage performance.
Starlite applies this knowledge to the proposal of ALP K03-406 resin labyrinth seals for turbo compressors.
Challenges we can discuss
Starlite reviews not only the material itself, but also the seal geometry and clearance design required for the operating conditions.
Compressor and seal issues
- You want to reduce internal leakage in a turbo compressor.
- Clearance design for labyrinth seals is difficult.
- Thermal expansion of resin seals is a concern.
- Metal seals may damage the rotor or mating shaft.
Material and design review
- You are considering resin replacement for labyrinth seals.
- Corrosion of metal seal components is a concern.
- You want to review resin materials for abradable seal concepts.
- You are considering large-diameter resin seal components.
Information useful for technical consultation
If you are reviewing resin labyrinth seals or low-CTE seal materials, the following information will help us evaluate the direction of the material and design proposal.
Operating conditions
- Gas type
- Temperature
- Pressure
- Rotation speed
Current seal design
- Current seal material
- Seal diameter
- Current clearance
- Mating shaft material
Required performance
- Required leakage level
- Contact or wear concerns
- Corrosion issues
- Maintenance or lifetime targets
Considering resin labyrinth seals for turbo compressors?
Starlite combines ALP K03-406 low-CTE resin material with material design, molding, machining, and evaluation expertise to support seal proposals for turbo compressor applications.