Abstract: The present invention relates to a spin coating apparatus for feeding a clean liquid at a fixed rate. In any of the feeding apparatus in the prior art, no constituent other than a filter has the function of eliminating foreign matter, and the operation of feeding a liquid under precise control is not attained. This results in the problem of the mixing of the foreign matter (and air bubbles) in the feed liquid, and the problem of nonuniformity in a feed speed as well as a feed amount. As expedients for solving these problems, the present invention provides the functions of automatically sensing and excluding factors for the appearances of the foreign matters, and devices for automatically and precisely controlling feed control elements such as a pump, thereby feeding the clean liquid in a constant amount and at a constant speed.

Abstract: A gas solenoid valve comprising a magnetic circuit formed with a fixed iron core, magnets and a magnetic member; a coil-holder movably provided with respect to the outer periphery of the fixed iron core and having a magnetic coil wound around itself; a sleeve accommodated within the magnets and spaced apart from the outer periphery of the fixed iron core for a predetermined distance; an actuating portion formed with the fixed iron core; the fixed iron core, the magnets and a magnetic member all fixedly covered with a molding resin from outside; and a governing portion engaged with the actuating portion.