Pulsation parameters of new and used milking liners with round cross section

G. Dineva*, K. Peychev, D. Georgiev

Department of Agricultural Engineering, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria

(Manuscript received 4 June 2021; accepted for publication 26 July 2021)

Abstract. Milking machines equipped with new and used milking liners with a round cross section were studied. The used milking membranes were operated for 3 months on a farm for rearing 60 cows (Holstein cattle) with double milking per day. The experiment involved recording the standard pulsation phases “a”, “b”, “c” and “d” (in absolute units) in the frequency range from 1 Hz to 2.5 Hz, in a vacuum mode of 40 kPa and 50 kPa and at a pulsation ratio of 50/50%. It was found that the transients (phase “a” and phase “c”) are faster and the established phases (phase “b” and phase “d”) are longer in milking units equipped with used milking liners. The conclusions are related to the service life of the milking liners.

Comparative study of a milking unit pulsation system in laboratory and field conditions

G. Dineva*

Department of Agricultural Engineering, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria

(Manuscript received 20 May 2021; accepted for publication 12 July 2021)

Abstract. A comparative study of the pulsation phases in classic milking units was performed. The testing of the same is done in laboratory and field conditions (during milking). The pulsation settings at which the test was performed were pulsation rate 60 min-1 and 90 min-1, ratio 50/50% and vacuum mode 50 kPa. The experiments were performed in the laboratory of “Machine milking” (Department of Agricultural Engineering, Faculty of Agriculture, Trakia University) on a milking installation with a pipe line and on a farm for 60 lactating cows at the same milking installation. It was found that the transients (phases “a” and “c”) are significantly reduced during milking. Respectively, the actual phases (phases “b” and “d”) are significantly increased during the milking process. The conclusions are related to the settings and timely diagnostics of the milking machine.