This simple design provides a rugged, reliable preventer and ease of service in the field.
- Strong Simple, Construction: Spherical blowout preventers consist of just five major parts - the upper housing, the lower housing, the sealing element, an adapter ring, and a piston. This simple design provides a rugged, reliable preventer and ease of service in the field.
- Spherical models in smaller sizes or with lower working pressures have bolted covers. Those in larger sizes or with higher working pressures have wedge covers. In bolted cover models, the upper housing fastens to the lower housing with studs and nuts. Wedge cover models fasten with locking segments and a locking ring.
- Simple Hydraulic System: Shaffer™ Sphericals require only two hydraulic connections- one for opening and one for closing. On some of the larger models additional ports are provided for convenience when attaching hydraulic lines.
- Space Saving Design: Sphericals are generally 15 to 20% shorter than comparable annular preventers- a big advantage when installation space is limited.
- The NXT design further decreases weight and height by eliminating the flange connection below the annular and directly connecting bolts through the base of the annular to the ram body.
- For applications that require two Sphericals, dual wedge cover preventers incorporate two sealing elements, adapter rings and pistons into one housing. Each sealing assembly operates independently, yet the dual preventer is up to 20% shorter than two singles stacked one on top of the other.
- Rugged, Reliable Sealing Element:The success of Shaffer™ Sphericals is due primarily to the ruggedness and reliability of their sealing element. Hundreds of pressure tests to full working pressure have proven its ability to maintain a positive seal. The sealing element of the Shaffer™ Spherical lasts two to four times longer than elements in other annular preventers. This is supported by the impartial tests conducted in an industry program sponsored by 22 companies, including all three major BOP manufacturers. The Shaffer™ element retains its ability to return to the fully opened position much longer than other sealing packers.
- The long sealing life of the element gives Shaffer™ Sphericals a high degree of reliability and minimizes maintenance and operating costs.
Features/Benefits
Shaffer™ Spherical blowout preventers are compact, annular type BOPs which seal reliably on almost any shape or size kellys, drill pipe, tool joints, drill collars, casing or wireline. Sphericals also provide positive pressure control for stripping drill pipe into and out of the hole. They are available in bolted cover, wedge cover, dual wedge cover, lightweight, and NXT models.
•Rugged, reliable, long-life sealing element provides positive seal after hundreds of tests to full working pressure.
•Strong, simple construction- only five major parts, which simplifies maintenance.
•Compact body saves space. Height is 15 to 20% less than height of some other annular BOPs..
•Simple hydraulic system; only two hydraulic connections are needed.
•Wear rings on moving parts prevent metal-to-metal contact, prolonging preventer life.
•Suitable for H2S service. Standard models are suitable for internal H2S service, and simple bolt and lifting shackle changes convert them for external H2S service.
•Servicing is easy. Element can be changed without getting mud or grit into the hydraulic system.
•Steel segments reinforce sealing element, but do not protrude into well bore when element is open.
•Sealing element design provides long stripping life.
