Expansion valve and refrigerating system

摘要

An expansion valve comprises an orifice 30 formed in a valve body 10 and a valve member 9 fixed to a movable member 18. Movement of a diaphragm 4 is transmitted to an actuating rod 17 via a member 16, and the actuating rod 17 actuates the movable member 18 to control the opening rate of the path between the valve member 9 and the orifice 30. A seat nut member 100 affixed to the orifice 30 has a large-diameter hole 108 and a small-diameter hole 110 directly communicating with each other. Hot pressurized refrigerant introduced into the large-diameter hole 108 heats a seat portion at the exit of the large-diameter hole, and prevents moisture in the refrigerant from freezing there.