Which Control Valve Diaphragm Material is Right for You?

Though small in size, the control valve diaphragm plays a critical role in oil and gas production. Control valve diaphragms are made with rubber a material referred to as “elastomer.”

In addition to the control valve diaphragm, elastomers are used in the seats and o-rings of control valves, regulators, temperature controllers, and most oil and gas control equipment.

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

How to Identify the Right Control Valve Diaphragm

A control valve diaphragm is made of different elastomers, 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:

  1. Operating Temperature
  2. Level of Potential Corrosion
  3. Level of Potential Wear
elastomer material, Diaphragm elastomer compromised by corrosive gasses

Control valve diaphragm 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. However, with the correct material you can run production longer before the elastomers require replacement. In the guide below, we have noted the wear resistance for each elastomer material.

Signs You May Need to Change Your Control Valve Diaphragm

Nitrile (also referred to as Buna) the elastomer we use for control valve diaphragms in standard packages. This elastomer is good for applications with a typical amount of wear and corrosive elements present in their product flow. We also offer other elastomers listed in the guide below.

elastomer material, control valve elastomers, o-rings, diaphragms

Seat elastomer compromised by corrosive gasses

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

  • The production fluid is high in corrosive materials (for example, you operating in the H2S-rich Permian Basin)
  • You’re injecting methanol to heat your gas line
  • You have a high-producing well, and your control valves must actuate multiple times per minute 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 – Gylon 3521
  • Production with H2S present – Aflas

Download Our FREE Guide to Control Valve Elastomers

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