Identifying changes in the milking rubber of milking machines during testing and under industrial conditions

Abstract

Milking rubber is the only part of the milking equipment that comes into direct contact with the cow’s teats. The task is to establish the high-quality technical and technological characteristics of the rubber liners for milking machines. It has been established that milking rubber after 600‒650 hours of operation acquires significant deflection in the range of 5.5±0.03–3.7±0.04 mm while a teat cup deformation varies within 1.3±0.02–3.5±0.05 mm. A positive correlation dependence of the milking rubber elasticity on the deformation of its teat cup (r=+0.948) has been found. The method of passing the electric discharge was used to assess the readiness of milking rubber for use, whereby a variation coefficient of υ˂10 % was determined for the milking rubber DD 00.041A AO «Bratslav», which makes it possible to estimate the product quality. It was found that the change in the mass and volume of milking rubber over 72 hours of its treatment with the liquid SZHR-3 at t=150 °C exceeds the indicators obtained in contact with the liquid Skydrol LD-4 by more than 2.5 times. A positive correlation dependence of the milking rubber mass on its volume (r=+0.965) has been established. It was found that at a rubber tension in the range of 0 to 90 N the duration of the deformation loss experienced by the milking rubber shell was not long; it is 0.05‒0.06 s. With an increase in the service life of milking rubber to 4 months, there is a decrease in its tension, from 56‒60 N to 43‒45 N, which adversely affects the maximum speed of milk yield – it decreases by 1.5 times. A positive correlation dependence of the milking rubber service life on the level of its bacterial insemination (r=+0.960) has been established