Phase-frequency characteristics of three types of milking clusters with a different volume and shape of the pulsation chamber

B. Banev, K. Peychev, V. Vlashev, G. Dineva
Abstract. Three types of milking clusters were examined: a conventional type with cylindrical pulsation chamber (round milking cup with round milking liner), a new type with a complex form of pulsation chamber (triangular milking cup with triangular milking liner) and composite type with the complex shape of the pulsation chamber (round milking cup with triangular milking liner). Pulsation systems of three types of milking clusters were tested in different operating modes which are changed by the following input parameters: a power vacuum of 40 and 50 kPa and pulsation frequency of 60÷150min-1 (1, 1.5, 2, 2.5 Hz). With pulsotester output parameters of the pulsation system were registered: phases a, b, c and d and pulsation amplitude. The analysis shows that within frequency range from 1 Hz to 2,5 Hz transient processes (both phases a and c) in the three types milking clusters decrease in absolute values but increase in relative values. On the contrary, at the same time the established processes (both phases b and d) only decrease in absolute and relative values. The phenomenon is that in the higher frequency range the relative influence of the transient processes increase within full processes (a+b) or (c+d). In this study the so called transient coefficients k and k are used as a criterion for evaluating the utilization of pulsation cycles and the effectiveness of milking clusters operation. The a+b c+d experiment in this study indicated that the combination of triangular shell and triangular milking liner demonstrate the best utilization of pulsation cycle: for the whole range of frequencies k changed from 24% to 60% and k varies from 14% to 30%. The reason for this good result is the weakening of the negative a+b c+d feedback due to inertia of the milking liner which with increasing frequency vibrates with less amplitude.