FILTERING MEMBER AND METHOD AND DEVICE FOR MANUFACTURING FILTERING MEMBER Russian patent published in 1996 - IPC

FIELD: filtering. SUBSTANCE: filtering member has perforated hollow rigid rod on which a twisted cord thread is wound in layers to form a rhomboid winding which consists of turns of the cord thread arranged about the perforated hollow rigid rod and placed to provide a variable density which increases to the periphery of the filtering member. The number of the parallel cord threads that form diamonds decreases in layers to the periphery of the filtering member from 6 to 10 cord threads at the perforated hollow rod up to 2-5 cord threads at the periphery of the filtering member. The number of threads in the diamond in each subsequent layer is less than that of in the previous one. The method of manufacturing the filtering member comprises winding cord thread on a perforated hollow rigid cylinder by way of rotation of the rod and reciprocation of the thread parallel to the axis of its rotation, the tension of the thread being simultaneously controlled. The winding is performed in layers. The ratio between the frequency of the reciprocations and rotation of the rod is maintained to be constant when a layer is wound and changes in transmitting from layer to layer. The device has feeding unit and receiving unit for winding a cord thread including thread distributor, drum holder, electric motor, driving mechanism, and unit for control winding. EFFECT: simplified method and design.