Hunting Energy Services (HES), Subsea Technologies Division, is a subsea hydraulic products manufacturer for the oil and gas sector. Its range of hydraulic valve products covers applications for production control, Intervention Workover Control Systems (IWOCS), and drilling control.
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As part of its dedication to manufacturing excellence, SAE standard AS4059 is used by HES to ensure the cleanliness of flushing and testing fluids to enhance the total quality of its instruments.
While it is not mandatory for HES to comply with this standard, it is accepted and its customers often demand compliance. This in turn helps to verify that its customer’s products are functioning correctly to mitigate expensive malfunctions during subsea operation.
Particle Analysis Challenges
When performing qualification testing, there were times when HES would purposefully use high levels of ISO 12103-1 Test Dust to contaminate test fluids to determine whether couplings or valves would malfunction as per customer requirements.
Fluid samples were delivered for testing at a local laboratory utilizing laser diffraction technology during one of the qualification tests. The company was unsure of the accuracy of the data when the results were returned from the external laboratory. It was suspected that some of the larger particles were not detected in the laser diffraction analysis.
The FlowCam flow imaging microscope was then adopted by HES. The company was interested to discover how the FlowCam results would compare to the laser diffraction results. For example, no particles greater than 65 µm were recorded with laser diffraction, while particles at this size and greater than 100 µm were detected using the FlowCam.
Source: Yokogawa Fluid Imaging Technologies, Inc.
Chart 1A. Customer’s Laser Diffraction Results. Laser Diffraction shows size bin results of particles as necessary for SAE standard AS4059. Indications show no particles greater than 70 µm. Image Credit: Yokogawa Fluid Imaging Technologies, Inc.
Chart 1B. FlowCam Result. FlowCam results demonstrate 748 particles per ML greater than 70 µm. Image Credit: Yokogawa Fluid Imaging Technologies, Inc.
Similar to other non-imaging technologies, the technology employed in laser diffraction converts all particles to an equivalent spherical diameter (ESD). Long fibers were counted as small spheres in some cases. There were other examples where translucent particles were completely undetected.
Laser diffraction is not a dependable technique for sizing and registering particles which have a low aspect ratio. The team at HES understood that the method they had adopted was significantly undercounting particles and was not detecting a number of others.
The FlowCam has provided us much better particle information on our fluids analysis over laser diffraction and manual microscopy methods.
Chris Roy, Engineering Manager, Hunting Energy Services
The laser diffraction technique that had been outsourced could not distinguish between fibers, air bubbles, and solids. Along with this, significant dilution was required with this method, needing rates up to 100:1 to function correctly.
No dilution was required when running the sample with FlowCam. One of the benefits of employing the FlowCam is that the company could deploy size bin filters to categorize and count particles of various sizes along with the AS4059 requirements.
Count data for particles in all of the size bins could be instantly provided by the FlowCam. A filter could also be created to identify and exclude air bubbles in the wash water which would unnecessarily skew the particle count.
As demonstrated in Chart 1A, no particles greater than 70 µm in size were detected by laser diffraction. With no images to support the data, companies who solely depend on laser diffraction may never discover what is undetected.
The Advantages of Flow Imaging
As it is a direct measurement technology, FlowCam particle imaging offers greater accuracy for particle analysis. No assumptions are made by the system regarding the spherical shape of any particle, and indirect measurements are not made for any particle-based upon reflection, shadows, or diffraction.
As each of the particles can be observed individually, all particles can be directly validated. FlowCam particle imaging is a more dependable particle measurement technique for use in mission-critical particle cleanliness applications.
Image 1. FlowCam digital images of particles greater than 90 µm, and even greater than 300 µm that were missed entirely by laser diffraction. Image Credit: Yokogawa Fluid Imaging Technologies, Inc.
This information has been sourced, reviewed and adapted from materials provided by Yokogawa Fluid Imaging Technologies, Inc.
For more information on this source, please visit Yokogawa Fluid Imaging Technologies, Inc.