Automatic drain valve

A drain valve assembly comprising:

• a valve housing having an inlet port and an outlet port and a water collection chamber between the inlet port and the outlet port;
• and
• a floating poppet positioned in the water collection chamber and arranged to be normally sealingly positioned across the outlet port to prevent water exiting the water collection chamber to the outlet port,
• wherein the floating poppet is attached to a pressure diaphragm across the water collection chamber such that when the pressure in the water collection chamber exceeds a predetermined opening pressure it causes the diaphragm to lift and to lift the floating poppet out of sealing engagement across the outlet port such that water can drain to the outlet port from the water collection chamber;
• wherein the floating poppet has a hollow body defining a channel from a first end of the floating poppet, adjacent the outlet, to a second end of the floating poppet, and
• wherein the housing defines a vacuum cavity across the channel at the second end, such that a negative pressure acting on one of the first or second ends of the floating poppet in a first direction, in use, is balanced by a negative pressure acting in direction opposite the first direction at an other of the first or second ends of the floating poppet;
• where the cross-sectional diameter of the first end of the floating poppet is equal to the cross-sectional diameter of the second end.