The Difference Between PTFE and Graphite Braided Packing

Packing plays a crucial role in preventing product leakage and prolonging the lifespan of valves, pumps, and other rotating equipment. When it comes to choosing braided packing, the primary factors to consider are pH value, temperature, and required shaft speed. PTFE and graphite packing are two popular material choices available in the market. In this blog post, we'll explain the differences between these options to help you determine the best pump packing material for your specific application.

Composition

Graphite Packing

Graphite is a naturally occurring form of carbon. To make graphite packing, multiple graphite filaments are heated and twisted together to form a yarn, which is then braided together to increase tensile strength and durability. Pure graphite packing is highly reliable in industrial applications since it withstands extreme heat and pressure. Typically, graphite packing has 95% carbon content or more. To further increase sealing performance, graphite packing can be coated with other lubricants like aramid or PTFE to fill gaps between the braided graphite fibers.

Flexible Graphite Packing

Flexible graphite, also known as expanded graphite, is made by oxidizing graphite flakes with sulfuric and nitric acids and exposing it to high heat. Doing so weakens the bonds between the layers of carbon and causes the layers to expand into a wormlike shape.

PTFE Packing

Unlike graphite packing, PTFE packing is comprised of synthetic materials. PTFE is a fluoropolymer of tetrafluoroethylene, also known as Teflon. PTFE packing can be made of 100% PTFE, impregnated with a lubricant, or a standard yarn that is dipped with PTFE.

Specifications: Comparing Graphite and PTFE

Graphite packing is highly conductive compared to PTFE and performs better in more extreme temperatures and shaft speeds since PTFE begins breaking down and carbonizing past 500 °F. Graphite packing is self-lubricating and can operate in wet or dry environments. Both have a low coefficient of friction, although PTFE’s is lower. PTFE is very resistant to chemicals, acids, gases, and corrosive substances except for molten alkali metals. PTFE’s white color doesn’t transfer, and other yarns can be dipped in PTFE to prevent color transfer when needed. PTFE is non-conductive and protects against shaft wear. 

Applications: Graphite and PTFE in Action

Graphite packing is ideal for applications involving high pressures, shaft speeds, and temperatures typically found in the following industries:

• Chemical Processing
• Equipment Manufacturers
• Marine & Dredging
• Mining, Nuclear
• Oil & Gas
• Power Generation
• Pulp & Paper

Due to PTFE’s resistance to chemicals and corrosive substances, Teflon packing works most efficiently for these industries:

• Chemical Processing
• Food & Beverage
• Electrical
• Pulp & Paper
  

Benefits: What Makes Graphite and PTFE Stand Out?

Expanded Graphite Filler

Due to graphite packing’s resistance to high temperatures, it’s widely used to process acids and oils. It can operate in dry or low-flush conditions since it’s self-lubricating. Graphite packing is also easy to install and maintain, making it an often cost-effective option. It’s a great substitute for asbestos filler.

PTFE packing has some inherent advantages over other types: its low coefficient of friction leads to a longer shelf life, it doesn’t bleed color so it’s FDA-approved for food and pharmaceutical processes, and its chemical resistance makes it popular for corrosive environments.

Products: Find the Right Fit for Your Needs

The choice between PTFE and graphite braided packing depends on your specific application requirements, such as temperature, pressure, and chemical resistance. By understanding the differences between these two popular materials, maintenance technicians and engineers can make an informed decision that best suits their needs.

If you have any questions or would like more information about PTFE and graphite pump packing, please don't hesitate to reach out to us. Request a quote for the ideal packing material for your application today!