Dairy Farm Energy Management Handbook - Wisconsin Department ...

Equipment Operation and Maintenance
Vacuum Pumps
Since vacuum pumps consume, on the average, 17 to 20% of the dairy farm’s
electricity, this area is an obvious target in managing energy use.
In this case, you may want to consider using variable-speed vacuum pumps
that can typically save 50 to 60% on electricity usage compared to regular,
constant speed pumps.
A regular vacuum pump is inefficient because
it’s always running at a constant speed –
regardless of how many milking units you use.
In the past, the normal industry standard for
sizing vacuum pumps was as high as 10 cubic feet per minute (cfm) per
milking unit, according to Sanford. Essentially, the regular vacuum pumps
were oversized to meet a theoretical, maximum demand, such as during the
start-up or fall-off stage.
However, research and experience have shown that the pump size can be
reduced by at least half, in many cases.
For example, a University of Wisconsin study indicated that the average air
consumption during milking is only about 2 cfm per milking unit.
Plus, thanks to computerization, a variable-speed drive pump can
instantaneously change or modulate its speed – high or low – to match and
maintain the necessary and optimum vacuum level required by the milking
system.
A variable speed drive can be added to existing vacuum pumps, but blower
type vacuum pumps work best, according to Sanford. Using a variable speed
drive can be justified economically, if the vacuum pump is running more than
6 to 8 hours per day.
Maintaining the vacuum pumps in good working condition is important to the
overall milking system performance. A faulty or poorly maintained vacuum
pump may result in slower milking times and have an impact on udder health.
(6)
The National Mastitis Council recommends a full test of the milking system at
least yearly by the installer or an experienced technician who uses special
measuring equipment and adheres to the standards established by the
American Society of Agricultural and Biological Engineers (ASABE).