Difference or variation on the same API designation screen

Some clients ask us about the accuracy of our screen panels tested under API RP13C. How can we assure that our screens made in large quantity are still in compliant with API RP13C? Do we need to test screen frequently? What will be the variation if it’s an inevitable consequence?

API Designation

API Designation is the screen size under API RP13C code. It’s a range of cut point of the whole screen panel. It can be known after being tested by a professional lab or 3rd party. There are professionals use special tools and devices. Such as testing powder, ASME filter, special software and so on.

Mostly, screens after being tested should indicate 3 data, including the D100 cut point, the non-blanked area, and the conductance. D100 cut point means the solids or particles larger than the finer number are to be separated out completely. As we know, each API designation holds a cut point range or separation point range but not a single point. For example, API 70 cut point range is 196~231 microns. That means, one certain panel of screen holds general opening between 196 and 231um. Our API 70 screen cut point is 204.51microns according to our test report. It’s in the range of 196~231microns

API screens panel

API screens panel

Variation may occur

We know the shaker screens are made from wire mesh/screen cloth. There are 2-3 layers of wire mesh, and the supporting profile on the backside. When we test screen according API RP13C, screen panel will be cut to a small piece for the convenient handling during test. If we got the test result of API 70 with cut point 204.51 microns on our screen sample, we’ll make the screens strictly according to our configuration, however, there will be a slight variation anyway.

But, the variation is less than 10 microns. Since the mesh size is fixed and wire diameter is confirmed, the variation may come from a different area, handling or tiny error of device.

The variation is an inevitable subsequence. No matter who makes the screens or who test screens. What we can do is, make all screen panels strictly the same as the sample tested. From the raw material selection to configure them. The factors we need to consider is wire diameter, mesh size accuracy, the profile, the piece cut, and the overlap among layers.

Do we need to test screens frequently?

Actually, against getting screen tested and marked according to API RP13C, we make screens strictly as per the configuration of samples. It should be no problem. The variation or difference is little. Maybe the cut point is larger or smaller but no exceeding 10 microns.

However, how about if the cut point just from a larger API designation to a smaller API designation? For example, our API 70 screen hold cut point 204.51, even there is slight difference to 194.51 in the range of API 60, it’s only 2 microns larger than 192. We know 1 micron equals to 0.001mm, such a situation is rather rare we can ignore it. Almost screens’ API designation are in the right range.

So, depends on the manufacturers. They can do the test for their new configuration, or check the accuracy to compare it with previous screens.

Furthermore, we think the screen pattern may affect the result of such a test. However, not many effects on the cut point. It may affect NBA and Conductance. If there are different models of the screen we can test them separately.

AIPU Solids Control is a professional manufacturer of shaker screens and mud processing equipment. Our screens have been tested according to API RP13C and we are the first one getting API RP13C report since 2014. Now, there are more and more suppliers doing the test. However, the core technique and high quality screens are still at AIPU Solids Control. If you have demand, please contact us freely. You will find that AIPU screens are different from others’.


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