Shaffer BOP Features, Mechanism & Manuals PDF
NOV Shaffer Blowout Preventers BOP stack field proved its efficiency in performing good isolation around the drill pipe, across the open hole, and for performing shearing on the drill string. Here you will be able to understand Shaffer BOP ram and annular preventer type components and function. Also, you can download Shaffer BOP manuals & catalogs.
https://www.drillingmanual.com/well-control-shaffer-sl-ram-blowout/