Fast powder changer for high-efficiency aluminum profile powder coating.

Liu Huangping, Li Baisong, Chen Xigui, Liu Jing'an
Guang aluminum Group Co., Ltd.
Zhongshan City Liheng Electrical and Mechanical Co., Ltd.
South Aluminum Group Co., Ltd.
summary: a brief introduction to the rapid powder change system of the basic technical requirements of each device, as well as the various devices to improve the powder rate and production efficiency of the function and role.
the transformation of the old horizontal line spray room, and compared the effect before and after the transformation, to prove that the modified rapid powder change device is a low-cost and efficient production equipment.
Foreword
With the promotion and application of aluminum profile products in the fields of housing renovation, personalized decoration, home furnishings, doors and windows, multi-color, multi-variety, small-volume spraying orders gradually increased by

.
traditional spray production line can not adapt to the market situation development needs, powder change slow, difficult to clean up spray equipment can only be used in mass production of monotonous color products.
, the development of a rapid powder change function of the powder room for aluminum profile surface treatment is of great significance.
Aluminum profile spraying powder room refers to a semi-closed, with good negative pressure ventilation without escape powder, and can effectively apply powder to the recovery device, is a specially used for powder electrostitectrical spraying of the chamber and circulation structure.
in the powder recovery operation of aluminum profiles, it is rare to use a recycling device alone, but to use more than two combinations of recycling devices in order to complement each other and get satisfactory results.
the transformation of aluminum profile powder spraying rapid powder change device consists of rapid powder change room, efficient cyclone recovery machine, secondary powder recovery device, rapid powder change center and so on. The overall facade arrangement of the spray room is shown in Figure 1.
layout of the spray room is shown in Figure 2.
1, the function of each part of the powder change device
1.1 rapid powder room
rapid powder room is generally used dry room, in the design and material selection and manufacturing should have the following functions:
(1) paint dust should not escape to the powder room openings;
(2) paint dust should not fall on the operator and spray gun, hand filling relative to the words, will not blow to the opposite side;
(3) powder room air flow should be distributed reasonably, can carry powder timely directional flow, to avoid turbulence. Air flow should not damage the application efficiency;
(4) should be from the structure of the powder chamber, to ensure that the excess powder coating does not remain in the powder room, the excess powder is immediately recovered by the system to the powder center, re-use;
(5) powder room using special anti-static engineering plastic plate manufacturing, not easy to adsorption powder, can ensure as little adsorption and high profile powder rate, cleaning color change is also very easy and fast
; The configuration of advanced automatic cleaning air flow knife, coupled with the flip plane cleaning system, downstream air flow control technology, to achieve the least powder retention effect and the fastest spray room cleaning speed;
(7) full-stroke cycle lift in the work, to avoid the motor in the change of the brake time (the old recidive lift every change to stop about 0.6s), to ensure the stability of efficient operation and will not accumulate powder.
1.2 High-efficiency cyclone recovery machine
cyclone recovery machine is the use of rotating dust gas generated by centrifugal force, the powder from the air separated from the gas solid separation purification equipment, characterized by simple structure, for the particle size of more than 10 m powder has a high recovery efficiency, easy operation, easy maintenance.
the traditional cyclone recovery machine for fine powders of less than 5 to 10 m, especially small density of fine powders, recovery efficiency is low, therefore, cyclone recyclers are mostly used for multi-stage recovery system first-stage treatment.
the cyclone recycler is a hollow structure. When powdered gas enters at a higher speed (usually 12 to 25 m/s) from the upper air inflow along the cutting direction of the outer cylinder, the air flow changes from linear to circular.
up and down, the upward air flow is blocked by the top cover to return, and the downward air flow does top-down helix movement (called an exo-cyclone) at the cylinder and cone parts between the inner and outer cylinders.
dust-containing gas produces a great deal of centrifugal force during rotation, and because the inertia of dust is many times greater than that of air, dust with a density greater than gas is thrown against the wall of the device.
dust, once in contact with the wall, loses its inertial force and falls along the wall by the momentum of the inlet speed and downward gravity, separates from the gas, and discharges through the cone into the peristaltic pump.
the outer cyclone current that rotates downwards is centered as the conical portion of the cone movements, and forms in the same rotational direction when the outer cyclone reaches a certain position in the lower part of the cone.
a spiral movement (called an internal rotary current) from the bottom to the next and discharges outwards through the inner cylinder. A portion of the unc collected dust also escaped.
efficiency of the cyclone depends on the amount of centrifugal force obtained by the dust. The centrifugal force obtained from dust in the cyclone can be obtained according to the following physical equations: type
: F is the centrifugal force obtained for the dust particles, N; R is the distance between the dust particle and the cyclone axis (i.e., the rotation radius), m;m is the mass of the dust particle, kg;
It can be known from this type that if the gas velocity of the cyclone inlet is certain, the smaller the diameter of the rotating radius or cyclone cylinder body, the greater the true density and size of the dust, the greater the centrifugal force obtained by the dust

high-efficiency cyclone powder unit with precise calculations, the single separation efficiency can be up to 98%. The cyclone recovery efficiency of powder particles of different diameters is compared in Table 1.
peristaltic pump is added to the bottom end of the large cyclone cone. It is best to configure with two peristaltic pumps so that a closed space is formed inside the cyclone, which can effectively transport the recycled powder to the powder supply center without leakage.
the recovered powder is matched with the new powder in a timely and effective manner, thus increasing the powder uivity and achieving savings.
1.3 Level 2 Powder Recovery Unit
When the Secondary Recovery Unit operates, the dust-containing gas enters the filter through the infleter of the unit and, through the filter element, the dust is isolated and accumulated on the outer surface of the filter element, while clean air enters the clean air chamber through the filter center and is finally discharged through the air drain above the filter element.
When cleaning the filter element, the pulse controller excites the solenoid valve to operate the thin film valve on the compressed air nozzle, and the high-pressure compressed air is sprayed through the nozzle, like a shock wave, removing dust from the filter element. Dust falls into the powder bin.
requirements of the secondary powder recovery device are:
(1) powder recovery efficiency should not
be less than 95%;
(3) the filter material used in the high-efficiency recovery device, should be used not easy to generate static electricity, blockage and moisture-absorbing materials, filter filtration efficiency of more than 99%, film filter can capture more than 0.3 m of dust, filtered gas into clean air, can be directly circulated in the plant
;
(5) the air volume capacity of the recovery unit should meet the requirements of the spray room and powder supply center that are connected to it.
1.4 fast powder supply center
powder supply center is the key equipment for rapid color change. As the core component of the spray system, the powder supply center can not only supply the powder continuously, uniformly and quantitatively to the spray gun, but also make the change of color of the powder more convenient and rapid, while the spray gun and pipeline can be automatically cleaned.
1.4.1 Composition of the powder supply center
the main body of the powder supply center is usually made of 1.5mm, 2.0mm sprayed steel plate, divided into the following parts: (1) pneumatic fluidization and Vibration composite powder supply barrel; (2) automatic lifting powder straw and powder pump; (3) back blowing rapid powder cleaning device; (4) fan and filter cleaning device; (5) recycling powder vibration sieve.
1.4.2 Rapid cleaning of the powder center
In color change cleaning, the center provides a strong pulsed airflow, quickly and efficiently and automatically clean the self-absorbing powder pipe, powder pump, spray gun inner tube and powder tube. Therefore, the powder supply center is an integrated part of the rapid color change system.
(1) Anti-blow powder tube quick cleaning device: When the spraying work is over and a new powder needs to be replaced, the powder accumulated in the straw tube and powder pump must be cleaned.
At this time remove the powder supply barrel, the straw and powder pump began to drop, and the head of the straw into the back blow hole seat, the use of back blow compressed air to clean up the original powder supply system, and ensure that the cleaning time is short, clean and thorough.
(2) Fan and filter cleaning system: for powder center work, due to fluidization and recycling system returned powder will cause some powder floating in the air, resulting in environmental pollution phenomenon, the built-in negative pressure device will use the wind generated by the recycling fan, the powder will be attracted to the wind pipe to the cyclone separation, to ensure the clean operating environment.
2, the use of
effects in February 2016 began to reform the old spray device, in which the spray gun is still used back to the original configuration of the spray gun. Subsequently, commissioning and trial production, in March began to officially put into production, the production line of profiles are mostly small single multi-color products.
the production data for the three, four and five months, and compared the production data for the same period in 2015, the effect is in Table 2.
From the table can be seen, through the old horizontal line spray room transformation, class production capacity has been improved, powder consumption reduced by 4.1 kg/t, powder change time shortened by 10min, waste powder rate reduced to 3.65%, the above can prove that the modified rapid powder change device is a low-cost and efficient production equipment.
3, small knot
after the transformation of the new aluminum profile electrostectrectrectrectrectrectrectration spraying device, after many tests and mass production practice has proved that it is a low-cost high-efficiency rapid powder change system, worthy of popularization and application.
.