Onoda Cement Co., Ltd.

Yasunari Okamoto

Tsutomu Itoh

Masahiro Yamamoto

Munekazu Sakurai

Senichi Masuda

Nobuo Furuya

Takehiko Ueno

Mitsuyoshi Kumada

Tatsuo Sugimoto

Katsutoshi Kozoe

Kenjiro Shimizu

Shinichi Kimura

A powder coating booth a function of supplying air though its ceiling. Sidewalls of the booth is formed from an insulating material or a semiconductor. A belt conveyor is disposed at the bottom of the booth. An electric field is formed so that it extends from a paint gun to the conveyor belt. The majority of oversprayed powder paint produced during painting becomes attached to the upper surface of a portion of the conveyor belt, is carried, together with this belt portion, to the outside of the booth, and is recovered from the conveyor by a blowing-type of static eliminator, thereby minimizing the mount of oversprayed powder paint mixed in an exhaust of the booth drawn through the sidewall.

Powder coating booth

A plurality of wire-shaped electrodes are arrayed at equal intervals within a plane insulator layer, and an electric power source for applying an A.C. voltage between adjacent ones of electrodes is connected to the electrodes via protective resistors so that an electric field in a curtain form is established between respective electrodes. The resistance value of the protective resistors between the electric power source and the electrodes and the resistance of the electrodes themselves are respectively selected higher than a minimum A.C. ignition resistance that is necessary for preventing ignition by spark discharge of powder to be processed by the curtain-like electric field. This prevents powder explosion induced by a spark discharge caused by a fault occurring in one part of the electric field curtain.

Safety type electric field curtain apparatus

An improved powder material processing apparatus is described herein, in which a plurality of wire-shaped electrodes are disposed within an imaginary plane at an equal interval and in parallel to each other. An insulator layer is interposed between the adjacent wire-shaped electrodes to prevent spark discharge from being generated by an A.C. high voltage applied between the adjacent wire-shaped electrodes. A silent discharge region is established between said adjacent wire-shaped electrodes, and positive and negative charges are separately given to the particles forming said powder material by making uncharged powder material pass through said silent discharge region, resulting in formation of powder material consisting of substantially equal numbers of positively charged particles and negatively charged particles, whereby control characteristics of the processed powder material can be greatly improved and the above-mentioned charging process can be effected continuously at a high efficiency.

Powder material processing apparatus

In an electric field curtain system, a plurality of linear electrodes are embedded in an insulator layer in parallel to each other along the surface of said insulator layer so that silent discharge forming curved electric lines of force which are outwardly convex may be produced on the surface of said insulator layer, the width of each of said plurality of linear electrodes is chosen equal to or less than 3 mm, and the interval between the respective linear electrodes is selected within a limited range, whereby every charged particle may be floated away from the surface of the insulator layer so as not remain on said surface.

Thin wire type of electric field curtain system

Growing community of inventors

Tokyo, Japan

Yasunari Okamoto