OIL PRODUCTION PUMPING WELLHEAD ASSEMBLY Russian patent published in 2007 - IPC E21B33/03 

FIELD: oil production, particularly sealing or packing boreholes or wells.

SUBSTANCE: wellhead equipment comprises chuck supported by production string flange and provided with eccentrically arranged coupling part to connect thereof to pressure pipeline with flow string from the first side and to secure thereof to T-joint with casing-head stuffing box from another side thereof. Flange part of chuck has radial and vertical orifices communicated with hole annuity and adapted to install bypass device and to cooperate with investigation instruments correspondingly. Chuck has safety valve inserted in radial orifice of flange part thereof to establish communication with hole annuity and injection line through channels. Channels are located in flange and bush parts of chuck correspondingly. Safety valve has seat and slide spring-loaded down the seat to retain the slide in working position and to deactivate thereof by means of hold-down screw.

EFFECT: extended functional capabilities and increased wellhead assembly reliability.

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