New API shaker screen designation

API Shaker screen designation predecessor

Shale shaker screens made of two or three layers of screen cloth of different mesh sizes present openings that cannot be easily characterized. A technique to describe these openings has been adopted by the API as the ‘‘Recommended Practice for Designations of Shale Shaker Screens,’’ API RP 13C, has been issued decade. This recommended practice supersedes the second edition (1985) of API RP 13E, which was valid for only single-layer screens.

The new API shaker screen designation system was chosen to convey information on screen opening size distribution and the ability of non-vibrating screens to pass fluid. Information for each of the following is legibly stamped on a tag attached to the screen panel in such a way as to be visible after the screen is installed on the shale shaker:

. Manufacturer’s designation . API number

. Flow capacity

. Screen conductance

. Conductance

. Total non-blanked area

Manufacturer’s Designation

The screen manufacturer may name a particular screen in any manner it desires. This designation is used when ordering a shaker screen with particular characteristics.

API shaker screen number

Shaker screen designation has been complicated by the advent of multi- layered screens. When two or three screens are layered together, the opening sizes are not uniform. Experience has shown that the flow rate through these layered screens is much higher than anticipated, and the solids-removal rate is maintained. Since the screens have different irregular shapes, the standard mesh equivalent cannot be used to describe the screens. API RP 13C was recently rewritten by a task group composed of most of the authors of this book. The task group selected a mechanical method of designating shale shaker screens and comparing them to equivalent square mesh opening sizes. This section describes this method for determining the API U.S. sieve number equivalent of a shaker screen using a laboratory sieve shaker, U.S. Standard Test Sieves, and sized grit samples. Screens are rated on the U.S. sieve number scale by the separations they achieve in dry sieving standard grit samples and comparing these separations to the separations of the same standard grit samples with standard U.S. sieves.

For example, a shaker screen that separates the grit sample similar to a U.S. 100 mesh test sieve is designated an API 100.