Seat Rings 101

When selecting seat rings (also called O-rings or sealing rings) for valves, engineers must focus on material properties to ensure reliable sealing, durability, and performance in demanding applications like oil and gas, chemical processing, or power generation. The choice hinges on temperature, pressure, and chemical compatibility. The most common seat ring materials – PTFE, CTFE, PEEK, and RPTFE – each bring distinct advantages, and understanding their differences is key to optimizing valve performance.

PTFE (Polytetrafluoroethylene, often branded as Teflon) is a go-to for its excellent chemical resistance and low friction, handling corrosive fluids like acids or bases across a temperature range of -100°F to 450°F (-73°C to 232°C). Its softness, however, makes it prone to deformation in high-pressure systems. CTFE (Chlorotrifluoroethylene, known as Kel-F) provides similar chemical resistance but with greater hardness, supporting higher pressures and temperatures up to 400°F (204°C). For harsher conditions, PEEK (Polyetheretherketone) offers exceptional mechanical strength and wear resistance, operating up to 480°F (249°C), though its rigidity demands precise machining. RPTFE (Reinforced PTFE), bolstered with additives like glass or carbon, enhances strength while retaining chemical inertness, making it ideal for steam or hydrocarbon applications.

The table below summarizes the critical properties to guide material selection: