Abstract: A workpiece which may be made of a highly electrically insulating material is held in a spaced opposing relationship with respect to a silent discharge plate electrode to which an a.c. voltage is applied. A d.c. voltage is applied across the workpiece and the silent discharge plate electrode to form a driving electric field therebetween. Powder particles suspended in air are charged in the same polarity as that of the silent discharge plate electrode and then injected into the region between the silent discharge plate electrode and the workpiece where the electric field drives the charged particles toward the workpiece to coat it. The a.c. voltage is sufficient to repel the electrode surface confronting the workpiece and to maintain the silent discharge at a reduced level and effectively precluding deposit of powder particles on the mentioned surface. An apparatus for the electrostatic coating is also disclosed.

Abstract: This invention relates to a process for electrostatically coating a substantially axially symmetrical object with pulverized material, characterized by supporting said object maintained at a temperature below the melting point of said pulverized material in an electrostatic coating chamber having a substantially axially symmetrical shape and equipped with silent discharge plate electrodes on the inside of said chamber; feeding electrically charged pulverized material into said chamber; electrostatically coating said object with said pulverized material by the action of silent discharge from said electrodes; and removing surplus pulverized material from specific parts of said object by suction.

Abstract: An electrostatic powder painting device provided with an improved powder electro-charging device is described herein, which painting device comprises a duct for conveying powder suspended in gas, an electrode chamber communicating with a slit formed along the entire inner circumference of said duct, a ring electrode disposed within said electrode chamber and having a substantially large radius of curvature in cross-section, a corona discharge electrode disposed at the center of said duct, gas introduction means into said duct through said slit, a voltage source for applying a voltage between said corona discharge electrode and said ring electrode, and means disposed in the proximity of the outlet end of said duct for regulating an ejection pattern of a powder cloud, whereby said painting device can maintain an highly excellent charging performance over a long period of time when the powder conveyed by the gas is charged with unipolar electric charge and also the most important performance of an electrostatic

Abstract: Forming electric field in and out of the vertical overlap portion, bottom peripheral joint portion and top peripheral rolled portion of a paper cup of paper or like material lined with a laminate, supplying charged powder particles in the space of said formed electric field to powder coating on said portions and with subsequent heat treatment, sealing layers are formed on said portions to become water tight; providing outside electrodes at the outside of said vertical overlap portion and folded portions and providing opposed electrodes in the inside of the paper container, providing a powder supplying means for blowing powder to said sealed portions and masking means for masking the portions not powder coated to securely seal said vertical overlap portion and folded portions.

Abstract: A novel metallic squeeze-out tube suitable for packing paste-like foods whose flavor is regarded as important or the like is described herein, in which a resin powder layer is formed on its inner surface and on the outer surface of its neck portion by electrostatic painting and thereafter it is finished by baking, whereby a resin coating film that is free from pin holes and has a strong corrosion resistance can be formed.

Abstract: This invention relates to a continuous process for electrostatically coating a substantially axially symmetrical object with pulverized material, characterized by conveying said object by means of a conveyor-type holding device into an electrostatic coating chamber equipped with silent discharge plate electrodes on both sides of the chamber walls: feeding electrically charged pulverized material into said chamber: electrostatically coating said object with said pulverized material by the action of silent discharge from said electrodes: and removing surplus pulverized material from the specific parts of said object by suction.

Abstract: An electrostatic powder painting gun head in which a needle electrode is provided at a central portion in the proximity of a cylindrical powder ejection port made of insulator, an annular strip electrode is disposed outside of the powder ejection port, also a gas injection port for forming a gas flow layer along the surface of the annular strip electrode is provided, and further there is provided a high voltage power supply for applying a predetermined voltage between the needle electrode and the annular strip electrode.

Abstract: On the downstream side of a large-diameter cylindrical flow path is disposed a small-diameter cylindrical flow path having a smaller inner diameter than the inner diameter of the large-diameter cylindrical flow path contiguously to the large-diameter cylindrical flow path, an annular electrode is disposed at the upstream end of the small-diameter cylindrical flow path, a needle electrode is provided at the center of the annular electrode applying a D.C. high voltage between the electrodes, and upon charging powder contained in a mixed-phase flow through said cylindrical flow paths, a substantial slip velocity is given to the mixed-phase flow adjacent to the surface of the annular electrode.

Abstract: A novel metallic squeeze-out tube suitable for packing paste-like foods whose flavor is regarded as important or the like is described herein, in which a resin powder layer is formed on its inner surface and on the outer surface of its neck portion by electrostatic painting and thereafter it is finished by baking, whereby a resin coating film that is free from pin holes and has a strong corrosion resistance can be formed.

Abstract: A container is disclosed made of paper which has an inner liner of synthetic resin material. Where the paper is exposed at the lap joint of the side, the joint between the bottom and the side, and the rolled lip, these are all sealed by a layer of resin material disposited as a powder and bonded to the inner liner by melting the powder resin while the same is in contact with the liner.

Abstract: 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.

Abstract: Forming electric field in and out of the vertical overlap portion, bottom peripheral joint portion and top peripheral rolled portion of a paper cup made of paper or like material lined with a laminate, supplying charged powder particles in the space of said formed electric field to effect powder coating on said portions and with subsequent heat treatment, sealing layers are formed on said portions to become water tight; providing outside electrodes at the outside of said vertical overlap portion and folded portions and providing opposed electrodes in the inside of the paper container, providing a powder supplying means for blowing powder to said sealed portions and masking means for masking the portions not powder coated to securely seal said vertical overlap portion and folded portions.

Abstract: 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.

Abstract: Forming coating layers at least on the whole inner side wall and top peripheral opening edge of a paper cup with synthetic resin to be closely adhered, also forming a coating layer with synthetic resin on the inside face of a bottom paper plate closely adhered, said coating layer at the lower peripheral edge of said inner side wall and the bottom coating layer are merged to be an integral part along the whole inner face of the cup, thereby leakage of liquid contained therein by penetration from said side wall, particularly from overlapped portion of side wall and from jointed portion of the side wall and bottom plate is prevented; also in the paper cup with a lid, leakage of liquid from the top opening end is prevented.

Abstract: A novel metallic squeeze-out tube suitable for packing paste-like foods whose flavor is regarded as important or the like is described herein, in which a resin powder layer is formed on its inner surface and on the outer surface of its neck portion by electrostatic painting and thereafter it is finished by baking, whereby a resin coating film that is free from pin holes and has a strong corrosion resistance can be formed.

Abstract: A bottle gripper for handling a bottle when depositing powder paint on the bottle in an electrostatic powder coating process and the like, the gripper comprises a cylindrical arm in which a shaft is inserted coaxially for relative movement in an axial direction. Several swingable pieces are attached to and are linked between the arm's lower end and the lower portion of each of the pieces, which forms a short thin cylindrical shell when gripping a bottle and is wrapped in a hat-shaped cover made of resilient material such as rubber with the outer rim of the resilient cover being fixed to the lower end of the arm in order to protect against entry of powder particles into the swing mechanism. The resilient cover is closed or opened by the relative movement between the arm and the shaft when gripping or releasing the head of a bottle.

Abstract: In a pair of surface-shaped silent discharge electrodes opposed to each other and separated by a predetermined space therebetween, phases of alternating voltages are applied to said respective silent discharge electrodes shifted in phase with respect to each other so that a silent discharge may arise alternately on either one of the electrode surfaces. A second alternating voltage is applied between the silent discharge electrodes and is alternatingly varied at a fundamented frequency twice as high as the frequency of the first alternating voltages applied to said surface-shaped silent discharge electrodes and is not inverted in polarity during the period when the silent discharge exists on either one of the electrode surfaces. Powder particles are passed through the space which separates the pair of surface-shaped silent discharge electrodes and charged in either positive or negative polarity continuously at a high efficiency.

Abstract: Silent discharge electrodes are provided in the proximity of a powder paint injection opening to generate silent discharge between these electrodes. Thus the voltage applied between a body to be painted and a painting apparatus and the discharge current flowing from said painting apparatus to said body to be painted can be respectively regulated independently of each other, and the flow pattern of ion currents in the painting space can be appropriately regulated, whereby the painting efficiency is enhanced and the quality of the painted film is improved.

Abstract: A face-silent discharge electrode which includes plural parallel electrode bars separated from each other at a distance and arranged in a face is disposed to confront a substrate. A powder coating material is supplied in the space between said electrode and said substrate. An AC voltage is impressed on the electrode bars adjacent each other to generate a silent electric discharge over the entire surface of said face-silent discharge electrode. Concurrently, a DC voltage is impressed between the electrode bars and the substrate so that the powder coating material may adhere to a surface of the substrate to form a layer of uniform thickness.

Abstract: 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.