Liner wall movement and vacuum measured by data acquisition

The objective of this study was to measure liner wall movement and define the characteristics of pulsation. The cyclic opening and closing of the milking machine liner is called "Pulsation." The liner opening and closing is a consequence of the differential pressures across the walls of the liner barrel. Liner wall movement was measured in the laboratory and during milking with an analogue laser sensor and a laptop computer equipped with a data acquisition system. Measurements were made in 10-s segments. The first and last cycles of 10 pulsations were dropped from each segment, and the average of eight cycles was used for final analysis. Opening and closing phases of liner wall movement were characterized at the intersection of 1 mm less than fully open and 1 mm greater than fully closed. The 'D' phase of the liner was 407 ms, in contrast to the 'd' phase of the chamber vacuum of 259 ms with an artificial teat. Time of liner opening averaged 87 ms with an artificial teat and 98 ms during milking. Liner closure time was 23 ms with an artificial teat and 42 ms during milking. Liner ratio was 57:43, with a chamber vacuum ratio of 65:35 using an artificial teat. Liner ratio was 58.2:41.8 with a chamber ratio of 64.5:35.5 during milking. This technology can be used to improve liner design and enhance milking performance.