Guide to Elastomers | How to Choose O-Rings, Diaphragms, and Seats for Your Control Valve

Though small in size, elastomers play a critical role in the oil and gas production. Elastomers are the rubber materials used in the diaphragms, seats, and o-rings of control valves, regulators, temperature controllers, and most oil and gas control equipment.

Selecting the right elastomer is key to keeping your production running smoothly. So, how do you know which to select?

How to Identify the Correct Elastomer

Elastomers are made of different materials, each designed to perform best under certain conditions. There are three primary data points you need to identify in order to determine which elastomer to select for a given application: Operating Temperature, Level of Potential Corrosion, and Level of Potential Wear.

control valve elastomers, o-rings, diaphragms

Seat elastomer compromised by corrosive gasses

  1. Operating temperature should be straightforward. How hot or cold is the liquid or gas funneling through your production process, specifically at the point where this item will be operating? Once you’ve determined that, you’ll address potential corrosion and wear levels.
  2. Corrosion in oil and gas production occurs when corrosive chemicals—including H2S, CO2, and any other acidic chemical—eat away at the elastomers and metals of your control valves, regulators, and other production equipment. Some elastomers are not affected by the types of chemicals that corrode metal, and vice-versa, which is why the selection of elastomers is important.
  3. Wear in oil and gas control valves occurs when there are high levels of actuation, causing consistent “wearing” on the internals of the equipment. Elastomer wear is ultimately inevitable, but with the correct material you can run production longer before the elastomers are compromised and require replacement. The grade of resistance for each elastomer material is noted on the guide below as “Wear Resistance.”

Signs You May Need to Change Elastomers

The standard elastomer Kimray offers is Nitrile (also referred to as Buna). This elastomer is good for applications and locations that have the typical amount of wear and corrosive elements present in their product flow. We also offer other elastomers listed in the guide below.

Diaphragm elastomer compromised by corrosive gasses

Diaphragm elastomer compromised by corrosive gasses

Here are some key indicators that you need to change elastomers from Nitrile/Buna to another material:

  • Your production fluid is high in corrosive materials (for example, you operating in the H2S-rich Permian Basin)
  • You are injecting methanol to heat your gas line
  • You have a high-producing well, and it’s causing your control valves to actuate multiple times per minute in order to control the flow
  • You are repairing your valve regularly (say once a month or more)

Best Elastomers for Common Applications

  • Saltwater – Nitrile/Buna
  • Glycol dehydration – Nitrile/Buna
  • Production with Methanol present – Highly Saturated Nitrile (HSN)
  • Production with H2S present – Highly Saturated Nitrile (HSN)

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