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The two-chambered teat cup (American Society of Agricultural Engineers (ASAE) 1984), consisting of a shell and a rubber liner, is the most commonly used device for mechanical milk removal. The teat cup removes milk from the teat, inserted into the liner, by applying a vacuum level of 35-50 kPa (pressure below atmospheric pressure) inside the liner. This continuously applied pressure differential across the lower part of the teat causes an outward deformation of the teat end in particular and opening of the streak canal resulting in milk flow. A pulsator provides pulsation, i.e. cyclic opening and closing of the teat cup liner. The pulsator switches the pressure in the pulsation chamber from atmospheric pressure to the nominal vacuum level of the milking system and vice versa. Pulsation rates, defined as the number of pulsation cycles per minute (ASAE 1984), commonly range from about 45 to 60 c/ min. Pulsation ratios, defined as the time ratio of increasing and maximum vacuum phase to all four phases (ASAE 1984),may vary from about 50% to 70%. Both pulsation rate and ratio are routinely measured for on-farm testing of milking systems.
measurement and analysis of milking machine teat cup operation
Reitsma, S.Y. and D.K. Breckman 1985. MEASUREMENT AND ANALYSIS OF MILKING MACHINE TEAT CUP OPERATION. Canadian Agricultural Engineering 27(2):91-98.
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