How to choose the right seal material according to the fluid？

In industrial sealing, there are no bad seals, only incorrect material choices for a specific application. Selecting a seal without considering chemical compatibility can lead to swelling, cracking or premature degradation of the elastomer.

The result? Leaks, unexpected downtime, contamination risks or even critical failures in the plant.

Here are just a few examples of the most recommended materials for industrial applications depending on the type of fluid:

Seals in contact with salt water: resistance to corrosion

In marine environments, ports or desalination plants, exposure to salt water is a constant challenge for sealing. Not all formulations can withstand it: the chloride content and the chemical aggressiveness of the medium can quickly degrade an unsuitable seal.

Recommended materials:

EPDM: good resistance to salt water and oxidation.

FPM: excellent behavior in aggressive chemical environments.

PTFE: virtually inert, ideal for extreme conditions.

Typical applications: offshore machinery, valves in naval installations, cooling circuits with brackish water.

Seals in contact with grease: thermal and chemical stability

In systems where there are lubricating greases (mineral, synthetic or even food-grade), the seal must withstand constant contact with hydrocarbons and high temperatures. Here, resistance to swelling, friction and thermal degradation is essential.

Recommended materials:

NBR: widely used due to its good price-performance ratio.

FPM: for synthetic greases or high thermal demands.

HNBR: better thermal performance than NBR with good mechanical resistance.

Typical applications: gearboxes, gear reducers, hydraulic valves, bearings.

Seals in contact with dairy products: certification and food safety

In the food industry, especially in the processing of milk and derivatives, choosing the right seal material is critical. It requires high chemical inertness, ease of cleaning, resistance to CIP/SIP systems and compliance with regulations.

Recommended materials:

VMQ (silicone): flexible, suitable for extreme temperatures, easy to sterilize.

Food-grade EPDM: resistant to cleaning products and steam.

White PTFE FDA: inert with a non-stick surface.

Required certifications: FDA, CE 1935/2004, USP VI, among others.

Typical applications: pasteurizers, dosing equipment, process valves, filling lines.

In addition to chemical compatibility, it is essential to verify that the O-ring meets the proper dimensional tolerances for effective sealing.

Also check:

• The inner diameter tolerance of the seal.

• The cross-section tolerance according to ISO3601.

• And the installation recommendations to avoid cuts, twists or incorrect assembly.