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For demanding industrial sealing applications, Graphite Packing stands as the superior choice. Engineered for extreme temperatures and aggressive media, Kaxite's graphite packing offers unparalleled reliability and longevity, reducing maintenance costs and downtime. Our products are manufactured using high-purity, flexible graphite, delivering exceptional performance in valves, pumps, agitators, and expansion joints across various sectors including chemical processing, power generation, and oil & gas.
Kaxite specializes in advanced sealing solutions. Our graphite packing is designed to meet the rigorous challenges of modern industry:
Kaxite graphite packing is available in multiple styles and densities to suit specific application requirements. Below are the key parameters for our standard high-flexibility graphite packing rings and coils.
| Property | Test Method | Typical Value | Units |
|---|---|---|---|
| Graphite Purity (Carbon Content) | ASTM D5617 | ≥ 99.9% | % |
| Specific Gravity (Density) | ASTM D792 | 1.1 - 1.3 | g/cm³ |
| Temperature Range (Inert/Reducing) | - | -240 to 3000 | °F |
| Temperature Range (Oxidizing) | - | -240 to 900 | °F |
| Thermal Conductivity | ASTM E1461 | 80 - 150 | W/m·K |
| pH Value | ASTM E70 | 6 - 8 | - |
| Compression Recovery | ASTM F36 | > 85% | % |
| Ash Content | ASTM D5617 | < 0.1% | % |
| Style Code | Form | Standard Density | Available Cross-Sections (Inch) | Standard Spool/Coil Length | Primary Application |
|---|---|---|---|---|---|
| KX-GP-F | Flexible Die-Formed Rings | High (1.3 g/cm³) | 1/8", 3/16", 1/4", 5/16", 3/8", 1/2" | N/A (Pre-cut sets) | Valve Stems, High-Pressure Pumps |
| KX-GP-C | Coil / Spool Packing | Medium (1.1 g/cm³) | 1/4", 3/8", 1/2", 5/8", 3/4", 1" | 50 ft, 100 ft | General Service Pumps, Agitators |
| KX-GP-R | Reinforced (With Inconel Foil) | High (1.3 g/cm³) | 3/16", 1/4", 3/8", 1/2" | N/A (Pre-cut sets) | High-Temperature Valves, Expansion Joints |
| KX-GP-W | Graphite Packing on a Wire | Medium (1.1 g/cm³) | 3/8", 1/2", 5/8" | 25 ft | Large Diameter & Irregular Shafts |
What is graphite packing made from?
Kaxite graphite packing is manufactured from exfoliated, high-purity (>99.9%) natural or synthetic graphite. The graphite is compressed into foil and then corrugated or wound into various forms (rings, coils) without the use of binders, resulting in a packing that is over 99% graphite by weight.
How does graphite packing compare to traditional braided packing like PTFE or aramid?
Graphite packing offers significant advantages over organic braided styles. It can withstand much higher temperatures (up to 3000°F vs. 500-600°F for PTFE), is chemically inert to a broader range of media, and has superior thermal conductivity. This leads to less heat buildup on the shaft, reduced wear, and longer service intervals, though it typically requires more careful gland adjustment during installation.
Is graphite packing suitable for rotating and reciprocating equipment?
Yes, Kaxite graphite packing is highly versatile. Its self-lubricating and conformable nature makes it an excellent choice for both rotary pump shafts and reciprocating valve stems. For high-speed rotary applications, we often recommend our reinforced style (KX-GP-R) for added durability and resistance to extrusion.
What is the proper procedure for installing graphite packing rings?
Clean the stuffing box and shaft/stem thoroughly. Use a sizing mandrel or the shaft itself to properly size and cut each ring. Stagger the ring joints by 90 degrees as you install each ring. Use a follower to push each ring firmly into place, ensuring it is seated squarely. Tighten the gland nuts finger-tight only for initial startup. After a short heat-up/run-in period (typically 15-30 minutes), retighten the gland gradually to achieve a slight leakage for cooling (about 1-2 drops per minute for rotating shafts).
How tight should the gland be on graphite packing?
This is critical. Overtightening is a common cause of failure. The gland should be tightened only enough to allow minimal, controlled leakage (a few drops per minute) for lubrication and cooling, especially in rotating service. For valves in static or slow-reciprocating service, a drip-free seal is often achievable. Always follow the manufacturer's torque specifications if provided, and never use excessive force.
Does graphite packing require a break-in period?
Yes. A controlled break-in period is essential. Start the equipment with the gland nuts just finger-tight. Allow the packing to warm up and seat itself for 15-30 minutes. Then, gradually tighten the gland in small increments (e.g., 1/6 of a turn) at 10-15 minute intervals until the desired leakage rate is achieved. This process allows the graphite to conform and form a stable seal without generating excessive friction heat.
What chemicals or media is graphite packing not compatible with?
While graphite is inert to most chemicals, its primary limitation is in strongly oxidizing environments at high temperatures. In the presence of pure oxygen, chlorine, strong oxidizing acids (like nitric or perchloric acid), or certain molten salts, graphite can oxidize or corrode above certain temperature thresholds (typically above 900°F in air). For such services, consult Kaxite engineering for specialized recommendations.
What is the maximum pressure rating for graphite packing?
The pressure capability depends on the packing style, density, and equipment clearance. Our standard high-density die-formed rings (KX-GP-F) are routinely used in valve applications exceeding 2000 psi. For very high-pressure rotary pump service (up to 5000 psi or more), our reinforced style (KX-GP-R) or specially engineered multi-density sets are recommended to prevent extrusion.
Can graphite packing be used in food or pharmaceutical applications?
Standard industrial graphite packing is not typically certified for direct food or pharmaceutical contact. However, Kaxite offers ultra-high purity grades with special manufacturing controls to minimize contaminants. For such applications, it is mandatory to discuss your specific sanitary requirements and compliance needs (e.g., FDA, USP) with our technical team to ensure the correct material is supplied.
What does the "Reinforced" style (KX-GP-R) mean?
The KX-GP-R style incorporates thin layers of Inconel alloy foil laminated between layers of high-density graphite foil. This reinforcement significantly increases the packing's resistance to extrusion under high pressure and temperature cycling. It also improves structural integrity and handling strength, making it ideal for severe service applications in power plants and refining.
How do I select the correct cross-section size for my stuffing box?
The packing cross-section is determined by the clearance between the shaft and the stuffing box bore. A common rule is: Packing Cross-Section = (Stuffing Box Bore Diameter - Shaft Diameter) / 2. It is crucial not to use oversized packing. Kaxite provides detailed sizing charts, and our technical support can assist in selecting the perfect size for optimal performance and seal life.
Does Kaxite offer custom graphite packing configurations?
Absolutely. Beyond our standard catalog, Kaxite engineers specialize in developing custom solutions. This includes special sizes, densities, composite constructions (e.g., graphite with other materials), pre-assembled cartridge sets for specific pump models, and packing tailored for unique thermal cycling or chemical exposure challenges. Contact our application engineering department with your specifications.
