초록 ▼

A differential fill valve assembly for application in float collars or shoes in well casing. The valve assembly comprises a back pressure flapper valve disposed within a substantially tubular upper housing, and a lower housing containing an activating sleeve slidably disposed therein above a double

A differential fill valve assembly for application in float collars or shoes in well casing. The valve assembly comprises a back pressure flapper valve disposed within a substantially tubular upper housing, and a lower housing containing an activating sleeve slidably disposed therein above a double flapper valve assembly. The activating sleeve initially extends into the upper housing to a sufficient extent to maintain the flapper valve in an open position; the activating sleeve is maintained in this position through use of shear pins, by which it is secured to the lower housing. The double flapper valve comprises a first flapper responsive to pressure below the valve assembly, and a second flapper responsive to force applied from above. A tripping ball is dropped to seat in the activating sleeve when it is desired to release the back pressure flapper valve; pressure applied on the ball moves the activating sleeve downward, releasing the back pressure flapper valve and swinging the double flapper valve assembly out of the flow path through the differential fill assembly, after which the tripping ball exits the bottom of the assembly. A lock ring maintains the activating sleeve in its lower position, while a shear screw riding in a longitudinal channel in the lower housing prevents rotation of the activating sleeve during its longitudinal movement prior to its contacting the double flapper valve assembly.

대표청구항 ▼

A differential fill valve assembly, comprising: substantially tubular body means having upper and lower longitudinal bores therein; back pressure flapper means secured to said body means, adapted to seat across said upper bore and including first spring biasing means; double flapper valve assembly m

A differential fill valve assembly, comprising: substantially tubular body means having upper and lower longitudinal bores therein; back pressure flapper means secured to said body means, adapted to seat across said upper bore and including first spring biasing means; double flapper valve assembly means including a larger and a smaller flapper, said larger flapper having an aperture therethrough, being secured to said body means and adapted to seat across said lower bore, said smaller flapper being secured to said larger flapper and adapted to seat thereon over said aperture, said double flapper valve assembly means further including second and third biasing means associated with said larger and smaller flappers, respectively; substantially tubular activating sleeve means having ball seat means in the bore thereof, a top and a bottom, slidably disposed in said lower bore between said back pressure flapper means and said double flapper valve assembly means, said top protruding above said lower bore and maintaining said back pressure flapper means in an open mode in a first longitudinal position, and releasing said back pressure valve means in a second longitudinally spaced position wherein said bottom protrudes below said lower bore and rotates said larger flapper to an open mode against said second biasing means; and sleeve locking means associated with said activating sleeve means and operable to maintain said activating sleeve means in said second position against said second biasing means.