Hunting Energy Services (HES), Subsea Technologies Division, is a manufacturer of subsea hydraulic products for the oil and gas sector. Its portfolio of hydraulic valve products spans a range of applications for production control, drilling control and Intervention Workover Control Systems (IWOCS).
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To improve the total quality of its instruments and as part of its commitment to premium quality manufacturing, HES utilizes SAE standard AS4059 to guarantee the cleanliness of flushing and testing fluids.
While it is not compulsory for HES to conform to this standard, it is recognized as customers usually demand compliance. This successfully confirms that its customer’s products are fully operational, mitigating any expensive malfunctions when in subsea operation.
Particle Analysis Challenges
When conducting qualification testing, there were occasions when HES would intentionally use high levels of ISO 12103-1 Test Dust to contaminate test fluids to establish whether couplings or valves would fail as per customer requirements.
Fluid samples for testing were supplied via a local laboratory using laser diffraction technology throughout one of the qualification tests. The company was hesitant concerning the reliability of the data when the results came back from the external laboratory. It was presumed that some of the larger particles were not found in the laser diffraction analysis.
HES subsequently adopted the FlowCam flow imaging microscope as the company was keen to learn how the FlowCam results would match the laser diffraction results. For instance, laser diffraction did not record any particles greater than 65 µm, whereas particles of this size and exceeding 100 µm were found 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.
Analogous to other non-imaging technologies, the technology used in laser diffraction converts all particles to a corresponding spherical diameter (ESD): in some cases, long fibers were counted as small spheres. There were also instances where translucent particles went completely undiscovered.
Laser diffraction is not a reliable technique when it comes to sizing and registering particles that possess a low aspect ratio. The team at HES realized that the method they had endorsed was undercounting particles to a large extent and was not identifying 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 delegated could not differentiate between air bubbles, fibers and solids. Additionally, considerable dilution was necessitated with this method, requiring rates up to 100:1 to properly function.
When running the sample with FlowCam, no dilution was necessary. Moreover, one of the main benefits of using the FlowCam is that the company could utilize size bin filters to count and classify particles of various sizes along with the demands of AS4059.
The FlowCam has the capacity to provide count data for particles in all of the size bins instantly. A filter could also be fabricated to distinguish and exclude air bubbles in the wash water, which would needlessly skew the particle count.
As exhibited in Chart 1A, no particles above 70 µm in size were identified using laser diffraction. With no images to uphold the data, companies solely dependent on laser diffraction may never find what is largely undetected.
The Advantages of Flow Imaging
As it is a direct measurement technology, FlowCam particle imaging delivers enhanced precision when conducting particle analysis. The system makes no assumptions in relation to the spherical shape of any particle, and indirect measurements are not produced for any particle based upon diffraction, reflection, or shadows.
As single particles can be individually observed, all particles can be validated directly. FlowCam particle imaging is a more reliable particle measurement method 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.