Tri-clamp connections are widely used in industrial settings for piping systems that transport liquids, gases or solids. A tri-clamp connection consists of two ferrules, a gasket, and a clamp that holds the ferrules and gasket together. The gasket is the sealing element that prevents leaks between the two ferrules. Different materials are used to make gaskets for tri-clamp connections, each with unique properties that make them suitable for specific applications. In this blog, we will explore the differences between three commonly used gasket materials: Buna-N, Viton, and PTFE, in terms of temperature range, chemical compatibility, pricing, and longevity.
Buna-N Gaskets
Buna-N gaskets are made from a synthetic rubber known as nitrile butadiene rubber (NBR). These gaskets have good mechanical properties, excellent resistance to oil and water, and are relatively low-cost compared to other gasket materials. Buna-N gaskets have a temperature range of -40°F to 212°F (-40°C to 100°C), making them suitable for most industrial applications. However, they are not recommended for high-temperature applications where temperatures can exceed 212°F (100°C) since they can become hard and lose their elasticity.
Buna-N gaskets have excellent compatibility with butane and propane, making them suitable for use in applications that involve these gases. They also have good compatibility with alcohols and ethanol. However, they are not recommended for use with some chemicals such as ketones, esters, and aromatic hydrocarbons.
Viton Gaskets
Viton gaskets are made from a synthetic rubber known as fluoroelastomer. These gaskets have excellent chemical resistance and can withstand a wide range of temperatures. Viton gaskets have a temperature range of -40°F to 400°F (-40°C to 204°C), making them suitable for high-temperature applications. Viton gaskets have excellent resistance to a variety of chemicals, including butane and propane, alcohols, and ethanol. They are also compatible with ketones, esters, and aromatic hydrocarbons.
Viton gaskets are more expensive than Buna-N gaskets, but they have a longer lifespan, making them more cost-effective in the long run. Viton gaskets have excellent compression set resistance, which means they can maintain their shape and sealing properties even after prolonged exposure to high temperatures.
PTFE Gaskets
PTFE gaskets, also known as Teflon gaskets, are made from polytetrafluoroethylene, a synthetic polymer known for its excellent chemical resistance and low friction properties. PTFE gaskets have a temperature range of -100°F to 500°F (-73°C to 260°C), making them suitable for extreme temperature applications.
PTFE gaskets are chemically inert and have excellent resistance to most chemicals, including butane and propane, alcohols, and ethanol. They are also compatible with acids, bases, and solvents. PTFE gaskets have a longer lifespan than Buna-N and Viton gaskets and can last up to ten years with proper installation and maintenance.
However, PTFE gaskets are the most expensive of the three gasket materials, and they can be difficult to install because they require a special process to seat them properly. PTFE gaskets are also not suitable for high-pressure applications because they have low tensile strength.
| Parameter | Buna-N | Viton | PTFE |
|---|---|---|---|
| Temperature Range | -40°F to 212°F (-40°C to 100°C) | -40°F to 400°F (-40°C to 204°C) | -100°F to 500°F (-73°C to 260°C) |
| Chemical Compatibility | Good with oil and water, butane and propane, fair with alcohols and ethanol | Excellent with a wide range of chemicals, including butane and propane, alcohols, and ethanol, as well as ketones, esters, and aromatic hydrocarbons | Chemically inert, excellent with a wide range of chemicals, including butane and propane, alcohols, and ethanol, as well as acids, bases, and solvents |
| Price | Low | Moderate to High | High |
| Lifespan | Moderate | Long | Long |
| Resistance to Compression Set | Fair | Excellent | Excellent |
| Tensile Strength | Good | Good | Low |
| Installation Difficulty | Easy | Easy | Difficult |
| Suitable for High-Pressure Applications | Yes | Yes | No |
| Resistant to Abrasion | Fair | Good | Excellent |
| FDA Compliance | Yes | Yes | Yes |
Overall, Buna-N gaskets are a good choice for low-temperature applications where chemical compatibility with oil and water is important, and cost is a concern. Viton gaskets are a good choice for high-temperature applications and where chemical compatibility with a wide range of chemicals is required. PTFE gaskets are a good choice for extreme temperature and chemical environments, but they are more expensive and require special installation techniques. It's important to consider the specific application requirements when choosing the right gasket material.
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