In demanding industrial sealing applications, few materials offer the unique combination of properties found in Polytetrafluoroethylene. For over two decades, Kaxite Sealing has been at the forefront of engineering and manufacturing advanced PTFE-based sealing solutions. Our PTFE packings are not just components; they are reliability engineered into a flexible, durable form, designed to withstand the harshest chemical, thermal, and dynamic challenges. Trusted by engineers across industries from pharmaceutical processing to chemical manufacturing and food & beverage, Kaxite Sealing packings deliver unmatched performance where failure is not an option.
The superiority of our PTFE packing products stems from the inherent properties of high-purity, premium-grade PTFE, enhanced through our proprietary manufacturing techniques. Here are the key benefits:
Our product line is designed to meet specific application needs. Below are the detailed specifications for our standard and enhanced PTFE packing series.
Ideal for general service in pumps, valves, and mixers handling acids, alkalis, solvents, and ultra-pure fluids.
| Parameter | Specification / Value |
|---|---|
| Material Composition | 100% Virgin PTFE filament, braided |
| Temperature Range | -200°C to +260°C (-328°F to +500°F) |
| pH Range | 0-14 (Full scale) |
| Specific Gravity | 2.1 - 2.3 |
| Tensile Strength | > 15 MPa (2175 psi) |
| Thermal Conductivity | 0.25 W/m·K |
| Available Sizes (Square Section) | 3mm, 4mm, 5mm, 6mm, 8mm, 10mm, 12mm, 14mm, 16mm |
| Standard Colors | White (Natural), Beige |
Formulated with food-grade or high-temperature lubricants (like graphite) for reduced break-in time and improved performance in rotary and reciprocating motion.
| Parameter | Specification / Value |
|---|---|
| Material Composition | PTFE filaments braided with food-grade silicone or high-purity graphite impregnation |
| Temperature Range | -100°C to +280°C (-148°F to +536°F)* |
| pH Range | 0-14 |
| Coefficient of Friction | 0.05 - 0.08 (Dynamic, against steel) |
| Primary Application | High-speed pump shafts, agitators, mixers, valves |
| Available Sizes (Square Section) | 3mm to 19mm in 1mm increments |
| Standard Colors | Black (Graphite), White (Silicone) |
*Temperature limit depends on lubricant type.
Highly conformable, gland-filling cord used for static seals, flange gasketing, and repacking valves in situ.
Q: What is the main difference between PTFE braided packing and ePTFE cord packing?
A: PTFE braided packing is constructed from twisted or braided filaments of PTFE, creating a dense, robust structure designed for dynamic sealing in pumps and valves (rotary/reciprocating motion). It handles higher shaft speeds and offers excellent extrusion resistance. ePTFE cord packing is made from expanded PTFE, a softer, highly conformable material. It is primarily used for static sealing, gasketing, and low-speed applications where its ability to fill irregular gaps is paramount. The choice depends on the motion, pressure, and required conformability.
Q: Can Kaxite Sealing PTFE packings be used with strong oxidizers like chlorine or nitric acid?
A: Yes, but with critical attention to temperature and concentration. Pure PTFE has excellent resistance to oxidizing agents. However, in packing forms, the performance can be influenced by the braid construction and any added lubricants. For hot, concentrated oxidizers like 98% nitric acid or wet chlorine gas, we recommend our Style KX-PT100 (100% virgin PTFE) and advise consulting our engineering team for specific service conditions to ensure optimal material selection and lifetime prediction.
Q: How do I properly install and break-in PTFE braided packing?
A: Correct installation is crucial. First, ensure the shaft/sleeve and stuffing box are clean, smooth, and free of damage. Cut packing rings on a clean, angled mandrel; stagger joints by 90 degrees. Install rings one at a time, seating each firmly with a tamping tool. For braided PTFE, initial gland follower tightening should compress the packing just enough to prevent significant leakage (usually hand-tight plus 1/4 to 1/2 turn). Start the equipment and allow a brief run-in period where minimal leakage is acceptable to lubricate and seat the packing. After 30-60 minutes of operation, tighten the gland incrementally (about 1/6 turn per bolt) until leakage reduces to the desired weep rate. Avoid over-tightening, as PTFE has low thermal conductivity and can generate excessive heat.
Q: Are there any media or conditions where PTFE packings are not recommended?
A: While PTFE is remarkably versatile, it has limitations. It is not suitable for applications involving molten or gaseous alkali metals (e.g., sodium, potassium) at high temperatures, as they can attack the fluorine-carbon bond. PTFE also has a known phenomenon of cold flow (creep) under sustained high mechanical load, which can lead to extrusion or loss of sealing force in static applications. For very high-pressure dynamic sealing, a composite packing or a different seal type might be more appropriate. Additionally, certain fluorinated compounds or specific chemistries at high temperatures may require evaluation.
Q: Does Kaxite Sealing offer PTFE packings suitable for FDA, USDA, or 3-A Dairy compliant applications?
A: Absolutely. Kaxite Sealing provides specific grades manufactured from FDA-listed raw materials (21 CFR 177.1550) and following GMP guidelines. Our pure white PTFE braided packing (KX-PT100-FDA) and specific ePTFE cords are designed for direct and incidental contact in food, pharmaceutical, and beverage processing. Documentation including Material Declarations and Certificates of Compliance is available upon request to support your validation processes.
Q: How do I select the correct size and style of PTFE packing for my pump or valve?
A: Selection requires key parameters: Shaft/Stem Diameter, Stuffing Box Bore, and Depth (to calculate number of rings). The packing cross-section is typically 1/8 inch (3mm) less than the radial clearance between the shaft and box bore. For high-speed shafts (>5 m/s), a smaller cross-section like 4mm or 5mm is often better for heat dissipation. For reciprocating rods or abrasive media, a braided style like KX-PT100 or KX-PT200 is preferred. For static flanges or low-speed valves, ePTFE cord (KX-PT300) is an excellent choice. Our technical team can assist with this calculation and recommend the optimal style based on your fluid, pressure, temperature, and speed.
The versatility of our PTFE sealing solutions makes them indispensable across a broad spectrum of industries. Common applications include:
