SU1207513A1 - Method and apparatus for depositing pulverulent polymeric coatings on metal articles - Google Patents

Abstract

1. A method of applying polymer powder coatings on metal products, which consists in fluidizing the polymer powder with gas, electrifying, electrostatically transferring it and depositing it on a product, characterized in that, in order to improve the quality of coatings by eliminating the aggregation of powder particles, on the powder during the deposition process affect the sound waves of the resonant frequency. (O y o CTi t f1 | GT1PPPP | II1T1PTPTP || 11 | -NT H / U U / XX "S - XX / S / X /: p / shsh with:

Description

2, Apparatus for applying powder polymer coatings on metal products, comprising a fluidization chamber with electrodes arranged therein connected to a high voltage source, and a pressurization chamber connected to a source of compressed gas separated from one another

The invention relates to the deposition of coatings, in particular to methods of applying coatings on metal products and to the designs of devices carrying out these methods.

The aim of the invention is to improve the quality of coatings by eliminating the aggregation of a part of the powder by acting on the polymer powder with sound waves having a frequency equal to the natural frequency of oscillation of the powder particles.

The drawing shows a device for implementing this method.

The device comprises a pressurized chamber 1 connected to a source of compressed gas (not shown), and a pseudo-liquefaction chamber 2 made of electrically durable material separated by a porous partition 3. In the chamber 2 electrodes are made, made in the form of grids 4 made of electric wire material and connected to one pole of a high voltage source 5 (IVN), between the electrodes 4. there is a rebar 6 to be coated, grounded and connected to another pole of the IVN, a working layer of polymer powder 7, a dynamic loud Speaker 8 connected to sound generator 9 through amplifier 0 of low-frequency ULF. In addition, the chamber 2 is provided with a device for uniformly moving it along the reinforcing bar 6 (not shown).

The device works as follows.

The powder polymeric material is loaded into the fluidization chamber 2 at a higher level of the lower electrode 4. In

7513

porous relocation, which means that, in order to improve the quality of coatings by eliminating the aggregation of powder particles, it is equipped with series-connected sound frequency generator, amplifier and dynamic loudspeaker.

pressurized chamber 1 serves dry purified compressed air, includes a dynamic loudspeaker 8, a high voltage source 5, and a device for evenly moving the chamber 2 along the rebar being covered 6. Occurring after turning on the dynamic loudspeaker 8 in the fluidization chamber 2

The sound waves act through the gas medium on the particles of the polymer powder and bring them into oscillatory motion. Change the frequency using the sound generator 9,

bring it to resonance, while the expansion rate of the working layer of powder 7 in the fluidization chamber 2 sharply increases, and the fluidization defects, expressed

in barbotizing and channeling, are completely eliminated.

The particles of the polymer powder under the action of sound waves and electrostatic forces make a complex resonant-vibrational-translational motion in the direction of the printed reinforcing bar 6. Due to this movement, the time the powder particles are in contact

proximity to the electrodes 4 increases, and when moving away, the distance from the electrode 4 to the particle of the polymer powder changes according to the law of particle oscillation, which contributes to the intensification and uniformity of the charge.

particles.

In the process of fluidization, intensive mixing of 40 powder in chamber 2 occurs, as well as contact contact between the particles of the powder and the electrodes 4. Among the particles

Due to the tribo effect of a polymer powder, particles can appear, which are charged electrically charged oppositely to that of electrodes 4, particles charged by the same charge, and particles that are not charged at all. with a charge that is opposite in sign to the electric charge, which the electrodes 4 have, are deposited on them and held until they are recharged. The polymer particles charged with the same electric charge with electrodes 4 will repel from them. Uncharged polymer particles in the process of fluidization and contact with the electrodes 4 are charged, acquiring an electric charge. The presence in the chamber 2 of the fluidization of the sprayed product (rebar) 6 having an electrical signal of the opposite sign to that of the electrodes 4 and with which particles of polymer powder are charged, will facilitate their orderly movement on the reinforcing bar 6 to be coated, and moving the chamber 2 along the reinforcing bar 6 at a constant speed will cause

Compiled by L. Yanushin Editor A. Dolinich Tehred Z.Kastelevich Proofreader T.

Order 82/6 Circulation 682 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Branch PPP Patent, Uzhgorod, st. Project, 4

a layer of polymer powder of constant thickness.

Dynamic loudspeaker 8 should have a mobile system, protected from falling into it of polymer powder.

Exhaust air is removed through the gaps between the sprayed reinforcing bar 6 and the walls of the fluidization chamber 2 by means of a local suction equipped with a no-i powder recovery filter (not shown).

The voltage on the electrodes 4 should be less than the voltage at which the process of ionization of the air-powder mixture between the electrodes 4 and the sprayed reinforcing bar 6 occurs to eliminate breakdown.

After the melting of coatings of thermoplastic polymeric materials, the technological process ends, and thermosetting materials must be polymerized, storing them at a certain temperature for the time required by the passport of the polymeric material.

The thickness of the coating is controlled by varying the speed of movement of the fluidization chamber 2 along the sputtered reinforcing bars 6.

Claims (2)

1. The method of applying powder polymer coatings to metal products, which consists in fluidizing the polymer powder with gas, electrification, electrostatic transfer and deposition of it on the product, characterized in that, in order to improve the quality of coatings by eliminating the aggregation of powder particles, the powder during the deposition process is affected by sound waves of resonant frequency. SU „„ 1207513 2. A device for applying powder polymer coatings to metal products, containing a fluidization chamber with electrodes located in it, connected to a high voltage source, and a pressurization chamber connected to a source of compressed gas, separated from one another by a porous bulkhead, which can be removed the fact that, in order to improve the quality of coatings by eliminating the aggregation of powder particles, it is equipped with series-connected sound frequency generator, amplifier and dynamic loudspeaker.