SCREENED PIPE Russian patent published in 2013 - IPC E21B43/08 

FIELD: mining.

SUBSTANCE: device comprises concentrically arranged outer and intermediate pipes, a reducing taper elbow. The outer and inner pipes in the upper part are connected between each other with tangential nozzles. The inner and outer pipes in the lower part are connected to each other also with tangential nozzles, which are aligned oppositely. The circular gap between the inner and outer pipes in the upper part, as well as the upper and lower parts of the inner pipe, are equipped with plugs. The outer pipe in the upper part is equipped with elastic rings, and in the lower part - with a plug. The intermediate pipe is equipped with a filtering element installed inside it and arranged in the form of a perforated back taper with a perforation coefficient from 50 to 85%, and arranged in an axisymmetrical manner to the intermediate pipe. Inside the taper there is at least one filtering element installed, which is made in the form of a perforated cylinder with perforation ratio from 80 to 90%.

EFFECT: increased duration of filter operation.

1 dwg