Vacuum pulsator unit for automatic milking machine - has pair of adjustable bleed valves to control frequency and phase of pressure fluctuations

摘要

The vacuum pulsator valve for milking machines comprises a pair of valve-members controlling the alternate application of vacuum and air pressure in a line connected to the pulsator. The pulsator includes adjustable bleed valves (19,21) operative to control the frequency of alternation and/or the phase length of alternation of vacuum and air pressure. The pulsator may be subject to compressed air or atmospheric air, and the bleed valves are adjustable externally of the pulsator body. One valve is moved alternately to the other valve between two positions to control a bleed passage communicating with the other valve for alternately applying vacuum and pressure to the other valve. For controlling the ratio of the pulsator cycle and thereby controlling the length of time the valve is subjected to vacuum or pressure, a needle valve is associated with the bleed passage.