AXIAL BLOWOUT-PREVENTION WELLHEAD STUFFING BOX Russian patent published in 2016 - IPC E21B33/03 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to the oil industry. A wellhead stuffing box is suggested, it contains an adapter with a tubular thread end for connection with wellhead fittings and a flange with a bore, in which a support of a tubular lip-sealing block is installed, the latter is made in the form of a flange. The support is fixed in the bore by a top flange such that the minimum clearance between the end surfaces of the bore, support and top flange ensure the possibility of the axial movement of the tubular lip-sealing block, and connection tightness is ensured by seals. Besides, the wellhead stuffing box has a blowout-preventing valve secured on the pressure coupling of the stuffing box and has a gate and a tracking-drive gear. At that the valve gate is made in the form of a disk with a seal and an eccentrically located axle for its rotation. The gate is located in the oil filled chamber created by the bore in the casing and flange. The tracking-drive gear is made in the form of a torsional spring, lever and roller. One lever end is secured on the gate axle, and on the second end the roller is hingedly installed, it is in contact with the stuffing box rod. The movable end of the spring is secured on the lever, and the fixed end - on the valve bonnet with a possibility of the spring tension adjustment.

EFFECT: increased reliability and durability of the stuffing box seal due to its unloading from transverse forces at the stuffing box rod side and assurance of the alignment of the stuffing box suspension point and wellhead rod through the full contact length with simultaneous aggregation with the disk blowout-prevention valve that is not in contact with the well product and operating in the protecting lubricant, simultaneous lubricating the wellhead rod accessible for inspection and spring tension adjustment, having the minimum force of contact with the wellhead rod by means of the roller out of a non-metal material, thus increasing its operation properties, reliability and durability.

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