Mud saver valve with increased flow check valve

In a mud saver valve for retaining fluids within a drill string when pumping is interrupted, the mud saver valve including a tubular body adapted to be disposed within the drill string and an axially movable piston having a fluid passageway and disposed within the tubular body, the piston being biased against the downhole flow of fluid by a spring, a closure plug mounted within the upper end of the mud saver valve and selectively engageable with the piston to prevent the flow of fluid through the fluid passageway, said closure plug comprising:

• a spear removably seated within the upper end of the mud saver valve, said spear including a spear sleeve detachably received within said upper end of the mud saver valve, a spear head telescopically mounted to said spear sleeve, and check valve means allowing fluid to flow upwardly through said closure plug when the fluid passageway is closed, said spear head telescopically extending relative to said spears sleeve when fluid pressure downhole of said closure plug exceeds a predetermined fluid pressure thereby opening said check valve means allowing fluid to flow upwardly through said closure plug, said spear sleeve including an outwardly disposed annular shoulder and said spear head including an inwardly disposed annular shoulder, said annular shoulders cooperating to limit the telescoping movement of said spear head relative to said spear sleeve.

A mud saver valve for retaining drilling mud within a drill string when downhole mud pumping is interrupted, said mud saver valve adapted to be disposed within a radially enlarged portion of the drill string, said mud saver valve comprising:

• a tubular body;
• an axially movable piston having a central fluid passageway disposed within said tubular body, said piston biased by a spring against the downhole flow of drilling mud;
• closure means supported in the upper end of said tubular body and selectively engageable with said piston, the downhole flow of drilling mud through said fluid passageway being prevented when said piston is biased into engagement with said closure means;
• a spear removably seated within the upper end of said tubular body said spear including a spear sleeve and a spear head said spear head telescopically receiving said spear sleeve within said spear head said spear head and spear sleeve having cooperating shoulder means for limiting telescopic extension of said spear head relative to said spear sleeve;
• check valve means in said spear, said spear head extending telescopically relative to said spear sleeve to open said check valve means allowing drilling mud to flow upwardly through said mud saver valve when said fluid passageway is closed and the fluid pressure of the drilling mud downhole of said mud saver valve exceeds a predetermined pressure.

A mud saver valve for retaining drilling mud within a drill string when downhole mud pumping is interrupted, said mud saver valve adapted to be disposed within a radially enlarged portion of the drill string, said mud saver valve comprising:

• a tubular body;
• an axially movable piston having a central fluid passageway disposed within said tubular body, said piston biased by a spring against the downhole flow of drilling mud;
• closure means supported in the upper end of said tubular body and selectively engageable with said piston, said piston disengaging from said closure means when the mud is pumped downhole through said mud saver valve and the downhole flow of drilling mud through said fluid passageway prevented when said piston is biased into engagement with said closure means;
• a spear removably seated within the upper end of said tubular body by at least one shear screw extending through the upper end of said tubular body, said spear including a spear sleeve and a spear head having a retaining sleeve telescopically receiving said spear sleeve;
• and
• check valve means in said spear, said spear head extending telescopically relative to said spear sleeve to open said check valve means allowing drilling mud to flow upwardly through said mud saver valve when said fluid passageway is closed and the fluid pressure of the drilling mud downhole of said mud saver valve exceeds a predetermined pressure, said spear sleeve including an inward retaining shoulder and said retaining sleeve including a cooperating outward retaining shoulder to limit the telescoping extension of said spear head relative to said spear sleeve.

In a mud saver valve for retaining fluids within a drill string when pumping is interrupted, the mud saver valve including a tubular body adapted to be disposed within the drill string and an axially movable piston having a fluid passageway and disposed within the tubular body, the piston being biased against the downhole flow of fluid by a spring, a closure plug mounted within the upper end of the mud saver valve and selectively engageable with said piston, the piston disengaging from the closure plug when mud is pumped downhole through the mud saver valve, said closure plug comprising:

• a spear removably seated within the upper end of the mud saver valve, said spear including a spear sleeve detachably received within said upper end of the mud saver valve, a spear head telescopically mounted to said spear sleeve, and check valve means allowing fluid to flow upwardly through the mud saver valve when the fluid passageway is closed and the fluid pressure downhole of the mud saver valve exceeds a predetermined fluid pressure, said spear head including a retaining sleeve having an inwardly disposed annular shoulder engaging said spear sleeve and said spear sleeve having an outwardly disposed annular shoulder engaging said spear sleeve and said spear sleeve having an outwardly disposed annular shoulder engaging said retaining sleeve, said retaining sleeve matingly receiving said spear sleeve to telescopically mount said spear head to said spear sleeve, said annular shoulders cooperating to limit the telescoping movement of said spear head relative to said spear sleeve.