Graphite PTFE packings are advanced sealing solutions engineered for demanding industrial applications. These packings combine the exceptional self-lubricating properties and chemical resistance of PTFE (Polytetrafluoroethylene) with the high-temperature stability and thermal conductivity of flexible graphite. This unique combination results in a robust sealing material capable of performing under extreme conditions, including high temperatures, aggressive chemicals, and dynamic service environments. They are widely used in valves, pumps, agitators, and other rotary or reciprocating equipment across various industries such as chemical processing, oil and gas, power generation, and pharmaceuticals.
Our Graphite PTFE packings are manufactured to precise standards to ensure optimal performance. Below are the detailed technical parameters for our standard product line.
| Parameter | Specification / Value |
|---|---|
| Material Composition | PTFE filaments intercalated with expanded graphite |
| Temperature Range | -100°C to +300°C (-148°F to +572°F) |
| Pressure Range | Up to 250 Bar (3625 PSI) |
| pH Range | 0 - 14 |
| Density | 1.8 - 2.2 g/cm³ |
| Tensile Strength | ≥ 15 MPa |
| Compression Set | < 15% (ASTM F36 Method A) |
| Thermal Conductivity | 5 - 10 W/mK |
| Coefficient of Friction | 0.05 - 0.10 (Dynamic, against steel) |
| Available Forms | Spooled cord, die-formed rings, coil packs, sheet stock |
| Standard Colors | Black (graphite), White (pure PTFE variants available) |
What is the maximum operating temperature for Graphite PTFE packings?
The maximum continuous operating temperature for standard Graphite PTFE packings is typically 300°C (572°F). For short-term excursions, some grades can withstand up to 350°C (662°F). It is crucial to consult the specific product data sheet, as the exact temperature limit can vary based on the media being sealed and the mechanical load.
Are Graphite PTFE packings suitable for potable water applications?
Yes, many grades of Graphite PTFE packings are manufactured to meet FDA and other international standards for contact with potable water. They are non-toxic, do not leach harmful substances, and are resistant to biofilm formation, making them an excellent choice for water treatment and distribution systems.
How do I determine the correct size and quantity of packing for my equipment?
The correct size is determined by measuring the shaft or stem diameter and the stuffing box bore diameter. The cross-sectional size of the packing ring or cord is calculated as (Stuffing Box Bore - Shaft Diameter) / 2. The quantity is the stuffing box depth divided by the cross-sectional size. Always refer to the equipment manufacturer's manual or consult with a sealing specialist to ensure accuracy, as an improper fit can lead to premature failure.
Can Graphite PTFE packings be used in high-speed rotary applications?
Yes, they are well-suited for a wide range of rotational speeds. Their self-lubricating nature minimizes heat generation and wear. For very high-speed applications (e.g., over 3000 RPM), it is essential to ensure proper installation, lubrication (if specified), and cooling to prevent overheating and potential degradation of the PTFE component.
What is the chemical resistance of Graphite PTFE packings?
Graphite PTFE packings offer outstanding chemical resistance. They are virtually inert to nearly all industrial chemicals, including strong acids, strong alkalis, halogens, and organic solvents. However, exposure to molten alkali metals and certain fluorine compounds at high temperatures should be avoided. Always check the chemical compatibility chart for the specific media in your application.
How long do Graphite PTFE packings typically last?
Service life varies significantly based on operating conditions such as temperature, pressure, speed, media abrasiveness, and installation quality. Under standard conditions in a well-maintained system, they can last for several years. In more severe services, life may be measured in months. Regular maintenance checks are recommended to monitor for wear and prevent unexpected failures.
What is the difference between braided and filament-style Graphite PTFE packings?
Braided styles offer higher structural integrity and are less prone to unraveling, making them ideal for dynamic applications with higher pressures and potential for extrusion. Filament styles, often with a core, provide excellent flexibility and conformability, which is beneficial for sealing irregular surfaces and in lower-pressure static or slow-reciprocating duties. The choice depends on the specific mechanical demands of the application.
Do these packings require a run-in or break-in period?
A proper run-in procedure is highly recommended for optimal performance and longevity. After installation, the packing should be gradually tightened in small increments while the equipment is running. This allows the packing to seat properly, distribute lubrication, and adapt to the operating conditions without generating excessive friction heat. The manufacturer's installation instructions should be followed meticulously.
