The invention relates to a novel heat-extraction well-mouth device used for an
oil field extraction work, which consists of a needle air-releasing valve, a seal
gate valve, an upper thread clamp-loop variable
diameter, a clamp seat, a lower thread clamp-loop variable
diameter, a clamp-loop, a restrictor, a small four-way device, a
flange clamp-loop variable
diameter, a wing valve, a screw protector, an upper
flange, a big four-way device and a
bushing flange. The needle air-releasing valve and the seal
gate valve, the lower thread clamp-loop variable diameter and the small four-way device, the small four-way device and the flange clamp-loop variable diameter, and the restrictor and the wing valve are respectively connected by the clamp loops. The clamp seat is seated on an upper step of the lower thread clamp-loop variable diameter, and the upper thread clamp-loop variable diameter is screwed with the lower thread clamp-loop variable diameter, and the screw protector is tightened in the upper flange. And the
bushing flange is firstly connected with the big four-way device through the bolt, then a steel ring is put into and the upper flange is connected with the big four-way device through the bolt. The invention solves the problems of the prior art that a
heavy load work cannot be done when a clamp-releasing or seal-releasing is done for a common heat-extraction well mouth; when in an air-injection, an oil pumping rob must be fully elevated and the air-injection work can be carried out. The invention can be widely applied to the
oil field extraction work.