In the course of their work, rotary feeders were studied, which continuously submitted the cod in the boiler of alkaline solution at a temperature of 160°C and a pressure of 1.2 MPa. At the same time, under pressure of the hydro-abrasive stream of alkali, wear and increase of the gap in the feeder occurs, which makes it impossible to operate the automated transport system. To reduce the gap in the feeder, the mechanism of the add-on of the rotor is used, which allows to continuously compensate for the gaps formed during wear during the year. The total amount of wear of the rotor and the body, which is used to compensate for wear in the nodes of friction, depends on the initial conicity and the magnitude of the axial displacement of one of the parts. During operation, under the action of an alkaline hydroabrasive medium, an increase in the clearance between the rotating rotor and the body occurs, which is accompanied by an increased alkali flow through the feeder and the cessation of the loading of the boiler's chip. To compensate for the gap, a special mechanism of the additive is provided, with the help of which the movement of the rotor in the axial direction to the depth of the conical body by 1-2 mmreduces the gap by 25-50 microns. Mathematical dependences are obtained for determining: the total wear of the connecting parts, the values of the angles of the taper and the biases of the joints. For automation of technological processes it is expedient to use in friction knots connecting conic surfaces which provide for a long time the cyclic compensation of the gap formed as a result of wear. The angles of the taper and the slopes on the interconnected surfaces are kept constant on both the rotating part and the non-rotating part. The angles of the taper and the slopes on the interconnected surfaces that came out of the connection vary from the original values. The total amount of wear of the rotor and the body that goes on to compensate for wear in the nodes of friction depends on the initial conicity and the magnitude of the axial displacement of one of the parts. Mathematical dependences are obtained for determining: the total wear of the connecting parts, the values of the angles of the taper and the biases of the joints. сопрягаемых деталей, величины углов конусности и уклонов сопряжений.