Vacuum Hose Pinch Valve

This compact Air Pressure Operated Valve was designed to shut off the milking vacuum to the cow by pinching the milk hose closed.

Only a rubber hose should be used for this purpose since a plastic hose is too stiff and would not spring back properly when released.

The standard valve (model F-40) operates with a rubber hose with an outside diameter of 1 inch. The model F-50 is identical in design, but is machined for the bigger imported hose with a 1.1 inch outside diameter.

Construction

The construction of the PBI Ross-Holm Pinch Valve takes the harsh environment of the milking barn into account. All parts are none corrosive and machined accurately to prevent premature failure. The valve head as well as the piston are made of a high quality engineering plastic proven to be able to take significant abuse. The return spring and air cylinder are both made of stainless steel as are the four screws used to keep the assembly together.

Operation

The Pinch Valve is slipped over the rubber hose in the proper location for Vacuum Shut Off operation. When air pressure is applied to the fitting on the end of the cylinder, the piston travels up, compressing the spring. In doing so it also protrudes into the opening through which the hose is inserted. The rounded end of the piston collapses the hose exactly the correct amount to form a complete closure. The piston travel is limited however to prevent damage to the hose when pinched. As the air pressure is removed the spring returns the piston back to the open position and the hose returns to its original shape conforming to the round hole in the pinch valve head.