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Increased milking vacuum in teatcups fitted with non-return valves

Published online by Cambridge University Press:  01 June 2009

R. Jeffrey Andrews ,
Graeme A. Mein  and
David M. Williams
R. Jeffrey Andrews
Affiliation:
Herd Improvement Laboratory, Grindle Road, Wacol, Queensland 4076, Australia
Graeme A. Mein
Affiliation:
Milking Research Centre, Institute of Dairy Technology, Werribee, Victoria 3030, Australia
David M. Williams
Affiliation:
Regional Veterinary Laboratory, Hamilton, Victoria, 3300, Australia
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Summary

An experimental non-return valve was fitted in the short milk tube so that flow was permitted only in one direction, away from the teat. Liner movement was minimal because no air admission to the liner above the valve was provided. The extent of liner opening therefore depended on the amount of milk extracted within a pulsation cycle and on any air leakage past the liner mouthpiece. Milking experiments using four cows showed that the mean vacuum level in nominally open liners of valved teatcups during peak milk flow was 8·6 kPa higher than in conventional teatcups. Bench tests showed that the increase in liner vacuum (LV) depended on the nominal plant vacuum level, the pressure difference between initial LV and maximum pulsation chamber vacuum, the liner elasticity and mounting tension. The main source of energy available to raise LV above the nominal plant vacuum is the release of strain energy, stored within the liner during the collapse phase of each pulsation cycle.

Type
Original articles
Information
Journal of Dairy Research , Volume 55 , Issue 4 , November 1988 , pp. 495 - 503
Copyright
Copyright © Proprietors of Journal of Dairy Research 1988

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References

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