The dissertation is devoted to increasing the efficiency of the process of machine milking by improving the milk transport regime by using a two-chamber collector of a milking machine with a portion intake of air into the milk of a prefabricated chamber in a compression phase.
Despite the high level of development of equipment for the mechanization of milking cows, the issue is raised not only to improve cow productivity and to improve the quality of milk, but also to maintain its quality during machine milking.
The removal of milk from the udder occurs due to vacuum pressure, the pressure difference in the udder and in the collector of the milking machine. In order to transport milk from the collector to the milk line, a pressure gradient is required, which is created by the constant inlet of air into the collector of the milking device through the throttling hole. In this case, the milk-air mixture is formed, and the ratio between the amount of milk and air changes during the milking time. The discrepancy between the operating modes and the design of the milking machine leads to a decrease in the productivity of the cows, the risk of the disease of cows to mastitis increases, and the transfer of pathogens from one to another. The main problem is the instability of the vacuum pressure in the sucking phase and the inadequate pressure gradient in the compression phase. It has been established that the systematic vibrations of the vacuum pressure reduce the usefulness to 14%, and unstable conditions of transportation cause milk foaming, dispersion and stratification of fatty balls which are subsequently deposited on the walls of the milk pipeline and, as a result, impair the quality of milk. The fat content of milk in the length of the milk pipeline can range from 0.1 to 0.45%.
The scientific and technical task is solved by connecting the collector chamber of the collector and the chamber of the pulsator with a throttle opening, which will enable to stabilize the vacuum pressure at the sucking rate and carry out qualitative transport in the compression stroke.
The constructional and technological solutions of milking machines are generalized and the nature of the influence of the regime-construction parameters of the oily apparatus on the stability and vibrations of the vacuum-vibrational pressure in the collector is established. Improved classification of lines by way of milk transportation and substantiated the design and technological scheme of the milking machine with the improved mode of operation.
The mathematical model of pressure variation in the sucking cycle, which describes the relationship between the diameter of the ducting hose and the diameter of the throttle and the actual intensity of milk yield, is obtained. The obtained model shows that the biggest influence on the pressure change is the diameter of the milk-pipe hose. Thus, with an increase in the diameter of the ducting hose from 10 mm to 14 mm, the drop in pressure decreases to 4-5 kPa, with a diameter of the milk hose 10 mm, the pressure drop reaches 10 to 12 kPa.
It has been experimentally proved that the stability of vacuum gauge pressure in the sucking cycle, within the limits of zootechnical requirements, will be when using the diameter of the throttle dot from 2 to 3 mm, and with an increase in the diameter of the ducting hose more than 12 mm. The use of the same dairy hose ds = 10 mm in combination with the small diameter of the throttling hole gives the oscillation Pxs from 15 to 17 kPa. This indicates an insufficient amount of air to raise a portion of milk into the milk pipeline. Dependence analysis shows that sufficient volatility of vacuum pressure and, therefore, the transport of milk and air mixture will be better when using the diameter of the milk hose 12 mm. The drop in vacuum pressure will be in the range of 18 to 11 kPa. When using a diameter of a milk-hose 14 mm, the drop in vacuum pressure will be in the range of 38 to 27 kPa, which is not enough to transport the milk-air mixture. When using the diameter of the ducting hose ds = 10 mm, the drop in pressure has critical limits of 10 to 7 kPa.
Application of the developed two-chamber collector in the milk line of the milking machine with portion air inlet, during the compression cycle, allows to stabilize the vacuum pressure in the suction stroke and to obtain a deeper pressure difference in the compression stroke, resulting in higher quality milk.
The estimated annual economic effect from the introduction of a two-chamber milking machine collector on a livestock farm with a livestock of 100 cows due to an increase in the completeness of extrusion by 1.56% and the preservation of milk quality is 69615 UAH.
Key words: milking mechanization, milking unit, vacuum pressure, milking hose, tootle hole, two-chamber milking cluster.
