Stuffing box and blow out preventing device for polish rods of oil well pumping units

Claim 2

A stuffing box for polish rods of oil well pumping units comprising in combination a cylindrically bored body portion, a cylindrically bored substantially cylindrical upper guide component formed of resilient elastomeric material situated in said body portion and surrounding the polish rod when said polish rod is positioned within said stuffing box for reciprocation therein, means to support said upper guide component within said body portion, and a plurality of substantially ring-line packing elements of resilient elastomeric material stacked one upon the other and upon the upper end of said guide component and a packing gland nut screw threadably engageable within said body portion and bearing upon the uppermost of said packing elements to compress same in sealing relationship with said guide component and said polish rod and a cylindrical sleeve surrounding said packing elements to enclose and restrain same against outward spreading movement, the diameter of said sleeve being slightly less than the inner diameter of said body portion whereby said packing elements and said sleeve are free floating within said body portion.

Claim 3

The invention according to claim 1 which includes a shut-off valve assembly secured to the lower end of said body portion, said shut-off assembly including an annular valve seat surrounding the lower end of the cylindrical bore through said body portion, a frustro conical flexible valve element, a base plate upon which said valve element is secured, means to hinge said base plate by one side edge thereof to base of said body portion whereby when said shut-off valve assembly is in the closed position, said valve element engages said seat thereby shutting off said cylindrical bore through said body portion, and spring means operatively connected between said body portion and said base normally urging said valve element into engagement with said seat, said valve element registering against the side of said polish rod when said polish rod is in position within the bore of said body portion.

Claim 4

The invention according to claim 1 in which the upper end of said guide component is conical when viewed in cross section, each of said packing elements having a concave conical under surface and a convex conical upper surface whereby the upper end of said guide component is engaged by the convex under surface of one of said packing elements, the remaining packing elements being engaged one upon the other in wedging relationship, the angle of inclination of the upper and lower conical surfaces being different from one another whereby the packing elements expand upon the polish rod when same are compressed as aforesaid.

Claim 5

The invention according to claim 3 which includes a shut-off valve assembly secured to the lower end of said body portion, said shut-off assembly including an annular valve seat surrounding the lower end of the cylindrical bore through said body portion, a frustro conical flexible valve element, a base plate upon which said valve element is secured, means to hinge said base plate by one side edge thereof to base of said body portion whereby when said shut-off valve assembly is in the closed position, said valve element engages said seat thereby shutting off said cylindrical bore through said body portion, and spring means operatively connected between said body portion and said base normally urging said valve element into engagement with said seat, said valve element registering against the side of said polish rod when said polish rod is in position within the bore of said body portion.

Claim 6

The invention according to claim 3 which includes a blow-out preventor assembly below said guide component, said blow-out preventor assembly comprising a cylindrically bored resilient elastomeric element normally freely surrounding said polish rod and situated within said body portion, means to restrain said element from upward and downward movement within said body portion, and an annular recess formed in the outer wall of said element defining with the wall of said body portion, an annular fluid chamber, sealing means surrounding said element above and below said recess for sealing off said chamber, fluid conduit means through the wall of said body portion communicating with said chamber for the injection of fluid under pressure to engage said element in sealing relationship with said polish rod and to close off said stuffing box completely if said polish rod is removed.

Claim 7

The invention according to claim 5 which includes a shut-off valve assembly secured to the lower end of said body portion, said shut-off assembly including an annular valve seat surrounding the lower end of the cylindrical bore through said body portion, a frustro conical flexible valve element, a base plate upon which said valve element is secured, means to hinge said base plate by one side edge thereof to base of said body portion whereby when said shut-off valve assembly is in the closed position, said valve element engages said seat thereby shutting off said cylindrical bore through said body portion, and spring means operatively connected between said body portion and said base normally urging said valve element into engagement with said seat, said valve element registering against the side of said polish rod when said polish rod is in position within the bore of said body portion.

Claim 8

The invention according to claim 5 in which the upper end of said guide component is conical when viewed in cross section, each of said packing elements having a concave conical under surface and a convex conical upper surface whereby the upper end of said guide component is engaged by the convex under surface of one of said packing elements, the remaining packing elements being engaged one upon the other in wedging relationship.

Claim 9

The invention according to claim 7 which includes a shut-off valve assembly secured to the lower end of said body portion, said shut-off assembly including an annular valve seat surrounding the lower end of the cylindrical bore through said body portion, a frustro conical flexible valve element, a base plate upon which said valve element is secured, means to hinge said base plate by one side edge thereof to base of said body portion whereby when said shut-off valve assembly is in the closed position, said valve element engages said seat thereby shutting off said cylindrical bore through said body portion, and spring means operatively connected between said body portion and said base normally urging said valve element into engagement with said seat, said valve element registering against the side of said polish rod when said polish rod is in position within the bore of said body portion.

Claim 10

The invention according to claim 1 which includes a blow-out preventor assembly below said guide component, said blow-out preventor assembly comprising a cylindrically bored resilient elastomeric element normally freely surrounding said polish rod and situated within said body portion, means to restrain said element from upward and downward movement within said body portion, and an annular recess formed in the outer wall of said element defining with the wall of said body portion, an annular fluid chamber, sealing means surrounding said element above and below said recess for sealing off said chamber, fluid conduit means through the wall of said body portion communicating with said chamber for the injection of fluid under pressure to engage said element in sealing relationship with said polish rod and to close off said stuffing box completely if said polish rod is removed.

Claim 11

The invention according to claim 9 which includes a shut-off valve assembly secured to the lower end of said body portion, said shut-off assembly including an annular valve seat surrounding the lower end of the cylindrical bore through said body portion, a frustro conical flexible valve element, a base plate upon which said valve element is secured, means to hinge said base plate by one side edge thereof to base of said body portion whereby when said shut-off valve assembly is in the closed position, said valve element engages said seat thereby shutting off said cylindrical bore through said body portion, and spring means operatively connected between said body portion and said base normally urging said valve element into engagement with said seat, said valve element registering against the side of said polish rod when said polish rod is in position within the bore of said body portion.

Claim 12

The invention according to claim 9 in which the upper end of said guide component is conical when viewed in cross section, each of said packing elements having a concave conical under surface and a convex conical upper surface whereby the upper end of said guide component is engaged by the convex under surface of one of said packing elements, the remaining packing elements being engaged one upon the other in wedging relationship.

Claim 13

The invention according to claim 11 which includes a shut-off valve assembly secured to the lower end of said body portion, said shut-off assembly including an annular valve seat surrounding the lower end of the cylindrical bore through said body portion, a frustro conical flexible valve element, a base plate upon which said valve element is secured, means to hinge said base plate by one side edge thereof to base of said body portion whereby when said shut-off valve assembly is in the closed position, said valve element engages said seat thereby shutting off said cylindrical bore through said body portion, and spring means operatively connected between said body portion and said base normally urging said valve element into engagement with said seat, said valve element registering against the side of said polish rod when said polish rod is in position within the bore of said body portion.

Claim 14

In a stuffing box which includes a cylindrically bored body portion through which a polish rod reciprocates; the improvement comprising a blow-out preventing assembly, said assembly including a cylindrically bored resilient elastomeric substantially cylindrical element normally freely surrounding said polish rod and situated within said body portion, means to restrain said element from upward and downward movement within said body portion, an annular recess formed in the outer wall of said element defining, with the wall of said body portion, an annular fluid chamber, fluid conduit means through the wall of said body portion communicating with said chamber for the injection of fluid under pressure to engage said element in sealing relationship with said polish rod, and to close off said stuffing box completely if said polish rod is removed, said recess being bounded by an inner wall and a pair of side walls one each extending from the upper and lower sides of said inner wall respectively and inclining outwardly from said inner wall towards one another thereby defining annular upper and lower wedge portions which are forced outwardly to contact with said wall of said body portion by the injection of fluid under pressure, and sealing means surrounding said elements above and below said recess for sealing of said chamber.

Claim 15

In a stuffing box which includes a cylindrically bored body portion through which a polish rod reciprocates; the improvement comprising a blow-out preventing assembly, said assembly including a cylindrically bored resilient elastomeric substantially cylindrical element normally freely surrounding said polish rod and situated within said body portion, means to restrain said element from upward and downward movement within said body portion, an annular recess formed in the outer wall of said element defining, with the wall of said body portion, an annular fluid chamber, fluid conduit means through the wall of said body portion communicating with said chamber for the injection of fluid under pressure to engage said element in sealing relationship with said polish rod, and to close off said stuffing box completely if said polish rod is removed, said recess being bounded by an inner wall and a pair of side walls one each extending from the upper and lower sides of said inner wall respectively and inclining outwardly from said inner wall towards one another thereby defining annular upper and lower wedge portions which are forced outwardly to contact with said wall of said body portion by the injection of fluid under pressure, and sealing means surrounding said elements above and below said recess for sealing of said chamber.

Claim 16

The invention according to claim 13 in which said sealing means on said element includes annular grooves formed around the outer wall of said element on either side of said recess and spaced therefrom, and resilient O rings engaging said recesses.