EXPERIMENTAL STUDIES OF THE STAND OF THE AUTOMATED MILKING UNIT WASHING SYSTEM WITH AIR INJECTORS AND A PHOTO SENSOR FOR DETERMINING THE CONTAMINATION LEVEL

One of the key indicators of the quality of milk used for further processing is the level of bacterial contamination. This parameter directly depends on the sanitary and hygienic maintenance of milking equipment, the speed of milk cooling and the influence of other external factors. During milking, milk passes through various elements of the system, such as milking machines, milk pipes, milk collectors, individual and group meters, etc. These elements can become sources of bacterial contamination. To improve the quality of milk, it is recommended to increase the efficiency of washing milking units, which includes extending the duration of washing. However, this leads to an increase in operational costs (water, detergents, electricity, etc.) and, accordingly, the cost of dairy products. Over time, deposits of an alkaline and acidic nature are formed on the inner surfaces of the milk ducts, which differ in composition, properties and strength of adhesion to the surface. This contamination leads to bacterial contamination of milk, which reduces its quality and shelf life [1]. To improve the quality of washing, it was proposed to use an injector that periodically supplies air to the milk line. This creates significant fluctuations in vacuum pressure, which, in turn, causes controlled hydraulic shocks. This process should be managed by automated milking equipment systems. The quality of the flushing system is difficult to assess and control without special sensors and devices for measuring the contamination of the milk duct [2]. The purpose of the study is to conduct experimental tests of the operating modes of the air injector of the milk duct washing system and determine its optimal parameters. It is also planned to develop equipment for automatic detection of contamination of the milk duct during washing. In experimental studies, the dependences between the rate of pressure change and the level of cleanliness of the milk duct, as well as between the working vacuum pressure, the volume flow of air through the injector, the duration of air intake and the duration of the pause were found. In order to achieve a compromise, which consists in minimizing the rate of pressure change at the maximum level of cleanliness of the milk duct, the optimal parameters of the injector operating modes were determined. The expediency of using the developed equipment for automatic control of contamination of the milk duct during washing is shown. The dependence of the thickness of the layer of milk moving in the glass tube on the resistance of the photoresistor, which is affected by the light partially absorbed by the milk, is also established.