Professional Manufacturer of High-Performance Expanded Graphite Gaskets for Industrial Sealing Solutions

Frequently Asked Questions (FAQ) About Expanded Graphite Gaskets

Q: What are the primary applications for expanded graphite gaskets?
A: Expanded graphite gaskets from Kaxite Seals are ideally suited for sealing flanges in systems involving high temperatures, aggressive chemicals, or thermal cycling. Common applications include heat exchangers, boiler manways, turbine casings, chemical reactor flanges, valve bonnets, and in pipelines for refineries and petrochemical plants. They are particularly effective where traditional non-asbestos gaskets fail due to temperature or chemical attack.

Q: How do I select the correct density or thickness for my application?
A: Selection depends on flange conditions. Standard density (1.0-1.1 g/cm³) is suitable for most applications. For higher pressure or to fill larger flange gaps, a higher density (up to 1.2 g/cm³) may be recommended. Thickness typically ranges from 0.5mm (0.020") to 3.0mm (0.125"). Thinner gaskets provide higher seating stress, while thicker gaskets offer greater conformability to uneven surfaces. Our technical team at Kaxite Seals can provide specific recommendations based on your flange rating, surface finish, and media.

Q: Can expanded graphite gaskets be used with all flange facing types?
A: They perform excellently on a variety of flange finishes, including serrated (phonographic) spiral, concentric, and smooth finishes. For optimal performance on smooth flanges, a corrugated or embossed graphite gasket is often advised to prevent over-compression and extrusion. It is crucial to ensure the flange is clean, undamaged, and properly aligned.

Q: What are the limitations of expanded graphite gaskets?
A: While highly versatile, they have two key limitations. First, in continuous oxidizing atmospheres above 850°F (454°C), graphite can oxidize, leading to gradual thinning. For such services, a jacketed or metal-reinforced design is used to protect the graphite edges. Second, they are not recommended for services with strong oxidizing agents like nitric acid, concentrated sulfuric acid, or molten salts, which can aggressively attack the graphite.

Q: How should expanded graphite gaskets be installed and torqued?
A: Correct installation is critical. Always use a new gasket on clean, dry flange faces. Apply a uniform, criss-cross bolt tightening pattern in multiple stages (e.g., 30%, 60%, 100% of final torque) to achieve even compression. Refer to the ASME PCC-1 guidelines for bolted joint assembly. The required torque depends on gasket style, size, and pressure class. Kaxite Seals provides detailed installation instructions and torque recommendations with every order.

Q: Are Kaxite expanded graphite gaskets compliant with industry standards?
A: Yes. Our manufacturing process and materials are rigorously controlled to ensure compliance with relevant international standards such as ASTM F1315 for flexible graphite, ASME B16.20 for metallic gaskets (for jacketed/kammprofile types), and various customer-specific specifications like API, DIN, and TA-Luft for emissions control.

Q: What is the shelf life and how should I store these gaskets?
A: When stored properly in their original packaging in a cool, dry, and dust-free environment away from direct sunlight and moisture, Kaxite expanded graphite gaskets have an indefinite shelf life. Avoid stacking heavy objects on plain sheet gaskets to prevent permanent deformation.

Q: Can you provide custom shapes and sizes?
A: Absolutely. Kaxite Seals specializes in custom-engineered sealing solutions. We can manufacture expanded graphite gaskets in any non-standard size, shape (oval, square, irregular), or with special features like alignment tabs, bolt holes, and instrumentation ports. We work from customer-supplied drawings, CAD files, or physical samples.