Abstract: A pulsator valve for a milking machine is disclosed which includes a pressure-limiting restriction applied to the air passage at an output connection to the teet cups. The pulsator is provided with a valve member of substantially flat annular form arranged to seat on an annularly surfaced valve seat within the pulsator valve and the pressure-limiting restriction is an orifice within this valve member arranged to seat downwardly on a valve seat around the output connection during outward air-flow from the pulsator valve so that the orifice is aligned with the output connection.

Abstract: Glass characterized by the introduction into its composition of K.sub.2 O amount to 4 to 7% by weight, in place of Na.sub.2 O. Such glass has an increased viscosity at the crystallization temperatures enabling the use of continuous production techniques without distortion of the resultant band.