Piston type valve for e.g. milk - has additional chamber with spindle seal on bellows side furthest from seat

摘要

The piston-type valve has a valve plate fixed to a spindle, sealed by a bellows in a valve chamber and acting against a seat. On the side of the bellows (24) furthest from the seat (15) and the chamber (11) is a further sealed valve chamber (25) with a sealed guide for the valve spindle (13). This is connected to a supply (30) of sterile or sterilising medium such as gas, air, steam etc. The pressure of this medium is greater or less than that in the valve inlet (17). The valve spindle guide can have a lip-type seal (26), or this end of the chamber can comprise an elastic membrane sealed to the spindle.