A pilot-actuated spool valve comprises a generally cylindrical valve cage having a central axial cavity open at both ends and a plurality of generally radial openings connecting the central axial cavity to the external cylindrical surface of the cage; a valve sleeve sized to slide within the central axial cavity of the cage and having a first sealing surface at a first end and a second sealing surface at an opposing second end; a piston responsive to fluid pressure at a pilot inlet of the valve; a piston rod connected at a first end to the piston and having a threaded second end opposite the first end; and a cap nut in threaded engagement with the second end of the piston rod securing the valve sleeve to the piston rod. The cap nut is sized and configured to provide a clearance gap between the cap nut and the valve sleeve when the cap nut is fully tightened onto the threaded second end of the piston rod.

A humidifier is provided, comprising: a pedestal, a water tank, a water storage chamber, an atomizer, a mist discharge passage, and a water flow control device. The humidifier further comprises an enclosure which is open in its upper portion and used for avoiding water leakage. The lowest point at an upper end of the enclosure is higher than the highest water level in the water tank after leakage.

A pilot-actuated spool valve comprises a generally cylindrical valve cage having a central axial cavity open at both ends and a plurality of generally radial openings connecting the central axial cavity to the external cylindrical surface of the cage; a valve sleeve sized to slide within the central axial cavity of the cage and having a first sealing surface at a first end and a second sealing surface at an opposing second end; a piston responsive to fluid pressure at a pilot inlet of the valve; a piston rod connected at a first end to the piston and having a threaded second end opposite the first end; and a cap nut in threaded engagement with the second end of the piston rod securing the valve sleeve to the piston rod. The cap nut is sized and configured to provide a clearance gap between the cap nut and the valve sleeve when the cap nut is fully tightened onto the threaded second end of the piston rod.

A humidifier is provided, comprising: a pedestal, a water tank, a water storage chamber, an atomizer, a mist discharge passage, and a water flow control device. The humidifier further comprises an enclosure which is open in its upper portion and used for avoiding water leakage. The lowest point at an upper end of the enclosure is higher than the highest water level in the water tank after leakage.