Which Seal is Ideal for Your Industry Needs?

When it comes to sealing your manufacturing equipment it’s imperative that you choose the right seal made of the correct material. The wrong seal can break, causing loss of product and time. Things can go even worse with unintended chemical reactions and contamination. It’s impossible to be sure unless you consult an expert, but here are a few examples of seals and their applications.

Static Seals

Static seals refer to seals which are placed between surfaces with no relative motion. These seals are perhaps the easiest to maintain and select because of the lack of friction. What need to be taken into consideration are the types of forces being exerted upon the seal. Temperature, chemical makeup, and pressure are the primary concerns when dealing with static seals.

Dynamic Seals

On the other hand, dynamic seals operate between two moving surfaces. Dynamic seals are defined as being reciprocating, rotary, or oscillating depending on the type of motion they are being used between. All of the considerations of static seals are taken in when considering which dynamic seal to use, with the addition of being able to withstand the friction from the specific type of motion against the seal.

Materials and Their Uses

Now that you know which type of seal you need, the specific material becomes the important question. Each material has its uses and more are being developed regularly to take into account new factors such as environmental regulations. Here are a few types of materials and their properties:

Ethylene Propylene Diene Monomer or EPDM is resistant to weathering, ozone, water, and steam. Some of the common uses for EPDM include systems that involve: brake fluids, alcohols, ketones, diluted acids and bases, as well as phosphate ester fluids. Compounds cured with peroxide have excellent compression set resistance.

Acrylonitrile-Butadiene or NBR is the most commonly used material in rubber seals. NBR has amazing resistance to hydrocarbon fluids, cold water, di-ester lubricants, and ethylene glycol fluids. The standard service temperature range is -55 to 250 degrees fahrenheit, but it’s possible to extend this range with specialty compounds.

Hydrogenated Acrylonitrile-Butadiene or HNBR is a version of the above nitrile rubber that has most or all of its double bonds saturated with hydrogen, providing greater heat resistance and chemical resistance.

Carboxylated Acrylonitrile-Butadiene or XNBR is another nitrile rubber that has been altered to improve certain attributes. This variant is best for applications that require greater tensile strength, modulus, and resistance to abrasion, good for dynamic seals and abrasive products.

Silicone Rubber has the broadest temperature range of standard elastomers with a range of -175 to 500 degrees fahrenheit depending on the composition. There is a trade off, though. Silicone products tend to have lower physical strengths compared to carbon elastomers. So, if your manufacturing needs are at extreme temperature, silicon tends to be a better choice.

Polyurethane rubber has the best physical strength and toughness of the elastomeric materials with still impressive temperature ranges from -65 to 300 degrees fahrenheit. This material is resistant to petroleum oils, fuels, oxygen, and ozone, but weak to acids, ketones, and water vapor.

Fluorocarbon Rubber or FKM is best for applications requiring both chemical and heat resistance, reaching up to 400F. These materials are good for use with petroleum oils, diester lubricants, silicate ester lubricants, silicone fluids, acids and bases, and more. There are even FDA grades available for food and beverage applications.

There are many more available options and this is only a brief overview.

Choosing the Right Seal

Choosing the right seal can be difficult. There are so many factors to consider based on each individual application. That’s why it’s best to have an expert source for your materials. Real Seal is an expert in all kinds of seals and will work with you to make sure you choose the right product. If you have unique challenges, new and custom compounds can be engineered to suit your needs. Contact Real Seal today to consult the seal experts.