Types of bushings for BG bottom heads
β 4-0 bushing; has internal and external o-ring seals to seal on the casing and inside the wellhead. Standard seal for general purpose wellheads.
β FS-S bushing; has FS seals in the ID to seal around the casing and S-Seals on the OD to seal in the wellhead. High pressure seal good up to 15,000 psi.
β FS-SL bushing; same seal as the FS-S only secured in the wellhead with an ACME threaded lock ring as opposed to a snap ring.
β PE seal; 4 piece seal consisting of an upper plate, 2β thick seal element, lower plate, and a snap ring. For low pressure applications.