AGENCEMENT DE PALIERS DE COMPRESSEUR A VIS, CE COMPRESSEUR ET PROCEDE POUR EMPECHER LE CONTACT ENTRE UN ROTOR ET UNE PAROI DE LA CHAMBRE DE TRAVAIL D'UN COMPRESSEUR

L'INVENTION CONCERNE UN AGENCEMENT DE PALIERS POUR ARBRE DE ROTOR DE COMPRESSEUR A VIS.IL COMPREND UN JEU DE PALIERS 30, 32, 34, 36 MONTE SUR L'ARBRE 18 DU ROTOR 16 ENTRE UNE PREMIERE CALE 28 ETABLISSANT LE JEU DE TRAVAIL 48 ENTRE LA FACE EXTREME 50 A HAUTE PRESSION DU ROTOR 16 ET LA PAROI EXTREME 46 A HAUTE PRESSION DE LA CHAMBRE 14 DE TRAVAIL DU COMPRESSEUR, ET UNE SECONDE CALE 60 DISPOSEE ENTRE LE JEU DE PALIERS ET UNE ENTRETOISE 56 ET ETABLISSANT UN INTERVALLE 70, INFERIEUR AU JEU 48 ET SUR LEQUEL LE ROTOR 16 PEUT SE DEPLACER AVANT D'ETRE ARRETE PAR LE CHAPEAU 24 D'EXTREMITE DU CORPS 12 DE PALIERS.DOMAINE D'APPLICATION : COMPRESSEURS A VIS. A first shim mounted on the shaft extending from the high pressure end face of a screw rotor in a screw compressor establishes the operating clearance between the high pressure end face of the rotor and the high pressure end wall of the compressor's working chamber by fixing the axial position of a bearing group which is likewise mounted on the rotor shaft. A second shim, disposed between the bearing group and a spring biased spacer element, is determinative of the distance the spacer element, and therefore the rotor, can travel in a direction toward the high pressure end of the compressor under the impetus of reverse axial thrust. Contact of the rotor with the high pressure end wall of the working chamber is positively precluded because movement of the spacer element, under the influence of rotor movement toward the high pressure end of the compressor, collapses the biasing spring which causes the spacer element to contact a fixed surface of the compressor. The spacer element contacts the fixed compressor surface and the reverse axial thrust is taken up by a roller bearing before the rotor can migrate sufficiently within the working chamber to contact the end wall of the working chamber. The biasing spring is selected to have sufficient strength to both preload the bearing set and to provide a limited amount of resistance, of itself, to reverse axial thrust while not being so strong as to cause significant frictional losses in the compressor or degradation of bearing life.