Abstract: Zonal isolation tools and methods of using same are described. The zonal isolation tools include a wellbore sealing member expandable by fluid pressure to contact a wellbore over an initial contact area, an inflation valve open during expansion of the sealing member to the initial contact area and closed upon the fluid pressure reaching a predetermined setting, a vent between the sealing member and a wellbore annulus adapted to open after the inflation valve is closed, and a compressive load imparted to the sealing member via a linear piston to achieve a sealing point at the leading edge of the sealing member. This abstract allows a searcher or other reader to quickly ascertain the subject matter of the disclosure. It will not be used to interpret or limit the scope or meaning of the claims.

Abstract: A fatigue resistant buttress thread. The thread has a load flank angle of approximately 30.degree. plus or minus approximately 5.degree. and a relief flank angle of approximately 46.degree. plus or minus approximately 5.degree.. The thread engaged depth is approximately 0.232 times the pitch of the thread, and the thread has a root radius approximately 0.175 times the pitch. The thread is particularly well adapted for use in cover retainers for holding valves and rupture discs in plunger pumps. Finite element analysis and actual tests indicate a greatly improved fatigue resistance compared to previously known buttress threads and other thread forms.

Abstract: An eccentric gear pump for use in pumping a variety of fluids. The pump has conventional plungers reciprocably positioned in a cylinder and includes a drive case with a rotatable drive shaft therein. The driven shaft is connected eccentrically to drive gears in a plurality of gear assemblies. Each gear assembly also includes a driven gear which has a yoke assembly eccentrically connected thereto. The yoke assembly is connected to a corresponding plunger. Rotation of the drive gear results in rotation of the driven gear which in turn causes reciprocation of the yoke assembly and plunger. Cam rollers are attached to opposite sides of the driven gear, and the cam rollers ride closely within a cam groove in a cam track on opposite sides of each driven gear. The interaction of the cam roller and the cam groove limits movement of the yoke assembly and piston to substantially purely reciprocal motion with respect to the drive case. Each gear assembly includes a pressure lubricated gear case.