Sentry lockdown screws, (LDS) utilize an external thread (ET) design that moves the threads outside the pressurized or wetted surface of the wellhead equipment. They utilize a robust Unified National Coarse (UNC) thread for the lockdown screw itself and the packing gland nut to minimize any galling. Additionally a one piece HBNR compression packing element with molded metal end caps to provide a dependable seal in multiple pressure ranges and service environments.
They mechanically retain items installed in the bowl of a head that are under pressure
They can be utilized to energize a compression seal or seals installed in the bowl of a head
They can be used to prevent an item installed in the head from rotating during the drilling phase of a well
They retain pressure in the flange of a wellhead assembly
The lockdown screw itself and the packing gland nut are designed with a robust bolt type thread to prevent galling
They utilize HBNR compression packing with molded metal end caps to provide a dependable seal in multiple pressure ranges and service environments