ICAR Technical Series no. 7 - Nitra Proc.

Gálik et al.The influence of mechanical, chemicaland biological ageing of liners onchange their propertiesR. Gálik, Š. Kovác & I. KarasKatedra mechanizácie zivocíšnej a potravinárskej výroby,Mechanizacná fakulta, Slovenská polnohospodárska univerzita,Kalvária 3, 949 76 Nitra, Slovak RepublicE-mail: r.galik@post.skThe work showes the results of physical and mechanical characteristics ofliners and condition their of inner side. These liners from two producersof milk technique were used in the working conditions. Hardness of linersis changing during the operational time statistically significant (highcorrelative coefficient r = -0,751; r = -0,5643).SummaryThe microstructure on inner side surface of liners verified the changes inexpored after 600 hours of service.Key words: Operating time, liners, hardness, surface film.Many authors have been busy with observation of physical and mechanicalproperties in their labours (Prikryl, 1988; Karas, 1996). These authorsmention, that changes in the physical and mechanical properties are verysmall comparing the starting values.IntroductionRough, hard and craced liners traumatized the peak of teat (Malík et al.,1989). By influence of mechanical strain is be coming on inside surface ofliners to creating microcrack, whose by time of usage growing and enlargetto all directions.Depending on working time of tested liners we detected the followedindexes (in the regular intervals after 300 hours of operation):1. Physical and mechanical characteristics of liners in laboratories ofResearching center of processing and aplication of syntetics in Nitra.1.1. Hardness [Sh A] by STN 62 1431.1.2. Resistance by broaking [MPa] by STN 62 1436.1.3. Tensibility [%] by STN 62 1436.Materials andmethodsICAR Technical Series - No 7207