Proprietry Couplings
In recent years, many proprietary couplings with premium design features have been developed to meet special drilling and production requirements. Some of these features are listed below.
Flush Joints: Flush joints are used to provide maximal annular clearance in order to avoid tight spots and to improve the cement bond.
Smooth Bores: Smooth bores through connectors are necessary to avoid turbulent flow of fluid.
Fast Makeup Threads: Fast makeup threads are designed to facilitate fast makeup and reduce the tendency to cross-thread.
Metal-to-Metal Seals: Multiple metal-to-metal seals are designed to provide improved joint strength and pressure containment.
Multiple Shoulders: Use of multiple shoulders can provide improved sealing characteristics with adequate torque and compressive strength.
Special Tooth Form: Special tooth form. e. g.. a squarer shape with negative flank angle provide improved joint strength and sealing characteristics.
Resilient Rings: If resilient rings are correctly designed, they can serve as secondary pressure seals in corrosive and high-temperature environments.