PACKER Russian patent published in 2007 - IPC E21B33/128 

FIELD: downhole equipment, particularly adapted for pressure testing of pipe string intervals in well.

SUBSTANCE: packer comprises mandrel with figured slot formed in outer surface thereof, wherein the slot includes alternating axial short and axial long parts. Packer also has support, sealing member and collar provided with guiding pin installed on the mandrel so that the collar may perform axial movement. Guiding pin is arranged in above figured slot. The collar is provided with spring centrators arranged along collar perimeter. Axial short and axial long parts of figured slot are connected with each other by closed figured part so that when the collar reciprocates along the mandrel guiding pin is alternately arranged in axial short part and in axial long part of figured slot. In transport position guiding pin is installed in axial short part. In working position guiding pin is arranged in axial long part. Mandrel section over the collar and below the support is correspondingly provided upper and lower radial channels. Upper channel has L1 length, lower one has L2 length. Annular recess having L3 length is formed in outer mandrel surface near lower radial channels. The L3 length is selected so that L3>L2 and L3>L1. Sealing member is arranged on outer mandrel surface and is retained by support from below and with collar from above. The collar may slide relatively mandrel within the limits of annular recess thereof. Weight is connected with mandrel from above. The mandrel is closed from below and provided with additional weight. Centrators are located on outer mandrel surface over radial channels. Centrators define circle circumscribed around centrators and having D₁ diameter, which exceeds D₂ diameter of sealing member in transport position. Figured slot section between short and long parts is provided with recess facing upwards and adapted to receive guiding pin during downward packer displacement.

EFFECT: possibility to perform pressure testing of small-diameter pipes, reduced time and decreased costs of repair works, reduced manufacturing costs.