Expert High-Velocity Oil Flushing Tips

Joe Orcutt, Gaubert

I’ve worked as a Project Manager at Gaubert IFM for over seven years. During this time, I’ve had the opportunity to work on many different high velocity oil flushes; I’ve been able to learn a few things along the way. This article contains some helpful tips for performing an oil flush or finding a high velocity oil flush service provider.

When it comes to planning and performing a high velocity oil flush, the goal is to get a quality job done as quickly, safely, and in as environmentally friendly a way as possible. For this to happen, certain steps must be taken. There are technical and human elements to high velocity oil flushing; when you’re looking for a flushing service provider, you should make sure they perform well in both categories.

High Velocity Flushing Project Tips

  1. Before starting or introducing oil, test all flushing circuits with compressed air; it's a lot easier to clean up an air leak than an oil leak.
  2. Remove any restrictions. All filters and flow orifices must go; they slow the flow.
  3. Cycle the coolers. Most units have two oil coolers and two filter vessels; do 12 hours on cooler A and then 12 on cooler B. Much of the debris gets trapped in the cooler, and if they aren’t properly cleaned, this debris will be reintroduced to the system after the flush is complete.
  4. Avoid hand-cleaning pipes whenever possible. It is a common practice in the industry to pull pieces of pipe from the machine, wipe them out, and then put them back in. This is insufficient; if a piece of pipe doesn’t fit where it’s at during the cleaning, try to loop it in elsewhere: on another jumper or the discharge of the pump. Hand cleaning is not a good substitute for flushing the pipe because you can’t achieve the level of abrasion, turbulent flow, or pressure that comes with a high velocity oil flush.
  5. Aim for a high Reynolds number. Most vendors require a Reynolds number of 4000 (the point at which laminar flow becomes turbulent flow), but this is too low. While turbulent flow is achieved at a Reynolds number of 4000, it is still not turbulent or abrasive enough to do a proper cleaning. I only do jobs with a minimum Reynolds number of 10,000; this cleans better and is faster (you can theoretically, but not always, cut flushing times in half).


  6. Chemically clean carbon steel pipe before flushing whenever possible. We use a simple acid. This step helps remove possible scale and rust build-up and ultimately speeds up the flushing process.
  7. Implement sparging and vibrators (this is one of the most important tips and tricks). Sparging, or gas flushing, is the introduction of air to the liquid and can increase the abrasive effects of the flush. Vibrators knock the piping to loosen and remove contamination build-up from the pipe walls.
  8. Run two verification screens to ensure a successful high velocity oil flush. If one screen passes, it doesn’t necessarily mean that the system is clean; it is always best to double-check.

Tips for Selecting a Service Provider

  1. 1. Be sure the service provider is prepared when they arrive on-site; this will avoid any delays on startup. There needs to be an engineering walk down, a good plan in place, and a marked-up drawings showing exactly what is going to be done to the system.
  2. 2. A quality flushing service should work with you, not for you. It is important for a service provider to become a team with the customer; this includes working together to form the flushing plan. You have information about your operations that the flushing service does not, and they need this information to do the job right. A flushing service that comes in with a pre-made plan does not consider the unique aspects of your machinery, which will lead to delays and insufficient cleaning.
  3. 3. The flushing service representative should over-communicate. They should get the e-mail addresses of everyone involved and send a nightly report detailing both what happened that day and the plan for the next. Financial records should also be included in this report. Constant communication allows you to follow the progress of the project and provides assurance that the flushing provider is not “nickel and diming” you with delays.
  4. 4. Ultimately, the flushing service providers are guests in your facility, and they should act as such. You should be informed of everything that is going to happen before it does, and you should sign off on everything.

Flushing Done Right

There is a lot of value in partnering with an experienced high velocity flushing service provider. Choosing a partner that works with you and gets the job done quickly means less downtime. When selecting a service provider, don’t be afraid to ask questions; it is crucial to make sure they know what they’re doing.

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