The pulsators act as valves that alternate between allowing air and vacuum to enter the teat liner and the pulsation chamber. The vacuum exerts a sucking action on the teat (the "milking" phase), which affects its physiology. The atmospheric air then acts as a "massage", recovering the normal state. Adequate alternation between massage and milking allows proper extraction and keeps the teat healthy.
Most pulsators in current use are electronic (pulsation boxes or individual cards), although pneumatic devices activated by vacuum can still be found.
The appropriate pulsation rhythm is between 55 and 62 pulses per minute. Systems typically allow the number of pulsations to be varied for each teat or else in pairs (front and rear). The ratio between the massage and milking phases tends to be between 55/45 and 70/30, usually 60/40.
There are two pulsation modes: alternating (by pairs of teats) or simultaneous (all four at a time). The second mode produces more milk extraction during the milking phase, while the first allows the flow arriving at the claw output to be reduced.
It is important to have technical information about the pulsators, such as consumption (liters/minute), operating temperature range, and work regimen (massage/milking and pulsation rhythm).
Milking (A-B) and massage (C-D) phases: there are specific minimum values (as percentages or thousandths of a second) for phases B and D, although it is important to precisely know all of these for each type of pulsator, since they allow any change to be evaluated as well as the efficiency versus other systems.
Maintenance of the pulsator
The pulsator must always be kept clean. Most cases of malfunctioning are due to fouling accumulated between the valve and the valve seat, although more serious problems can also arise because of obstruction of the atmospheric air inputs, above all caused by flies.
Individual or common filtering systems have been developed to prevent problems involving dust and dirt (using paper filters or even car air filters). These facilitate maintenance by extending the time between successive cleanings (less wear on parts by handling). However, if these filters are not properly monitored they can represent a complication, since if they become blocked the negative effects are more difficult to assess.
The electrical current must be monitored since voltage drops can affect the pulsation box (to a greater or lesser degree depending upon the manufacturer) or the individual pulsators (above all due to defects in old systems or poor design of the system using very thin cables).
|Dirty pulsator panel||Diassembled Alfa pulsator|
The gaskets must be periodically replaced. Depending on the type of pulsator, the gaskets for the plungers or the closure valves must be replaced, as well as those that adjust the various parts of the device.
Verify their functioning regularly. This can be done by creating pulsation and fluctuation graphs that allow the phases, closure, etc. to be checked.