Developing steel drum coating equipment
Beijing Fuheng Coating Equipment Promotion Center Zhu Yuyu
(Technology and equipment consultation)
In the past 30 years of reform and opening up, the technology and equipment of the barrel industry in China have developed greatly. Especially in the past 20 years, the steel barrel painting equipment has been researched and reformed continuously, and a very perfect steel barrel coating system has been formed. . Today, the steel drum coating technology led by Beijing Fuheng Coating Equipment Promotion Center has always been in the leading position in China.
First, the treatment of steel drum before painting
1. Why should steel drums be pretreated?
Pretreatment of steel drum is an important basic process, which has an important impact on the coating quality of the entire steel drum, the service life of the coating film, and the appearance of the coating film. Through the treatment before the steel drum is painted, it is found that various treatment methods are used, and the quality of the coating film after coating is greatly different. The quality of the pre-painting treatment is inferior or not pre-treated, and even if high-grade paint is applied, good coating quality cannot be obtained. When there is a quality problem in the coating of steel drums, it is too late to think that the pretreatment of the steel drum is too late. Therefore, it is recommended that the steel drum manufacturer should pay attention to the pretreatment of the steel drum.
The following are the results of two years of exposure to steel plates treated with different treatment methods before painting, using the same paint and exposed to natural conditions in the South.
Table 1 Comparison of Corrosion Resistance of Different Pretreated Steel Sheets
Serial numberPretreatment method
Corrosive surface
Salt spray test results
1
Unprocessed
60%
The steel plate coated without pretreatment began to rust in 150 hours, and the steel plate treated before painting did not rust within 300 hours.
2
Chemical rust removal
15%
3
Manual derusting
20%
4
Phosphating
Only individual
2, pre-processing method
Generally, mechanical treatment and chemical treatment are used. The so-called mechanical treatment is to remove rust with sandpaper, wipe the surface grease and other dirt on the steel drum; the so-called chemical treatment is to remove the oil stain and corrosion on the surface of the steel drum with chemical liquid, and then use chemistry. The chemical solution causes the surface of the steel drum to be phosphating. Among them, the steel barrel pretreatment is carried out by mechanical means, and the quality is unstable. Take the cloth and rub the surface of the steel drum with grease and other dirt. When the cloth rubs a few steel drums before it is effective, but after a few effects are worse, especially the last few may be worse than not rubbing. Because the oil on the surface of the steel drum has been glued on the rag before rubbing the front steel drum, these oil stains are stuck on the steel drum being rubbed. For this reason, it is necessary to paint the steel drum with good quality or chemical treatment.
3. Introduction to the latest chemical processing equipment designed by our company
(1) Horizontal processing of steel drum:
The so-called steel drum horizontal pre-treatment equipment is the steel drum or barrel horizontal type in the processing line for degreasing and phosphating (now generally adopts new cold-rolled steel sheet, so there is no need to remove rust).
crafting process:
Pre-degreasing → degreasing → 1 washing → 2 washing → iron phosphating → 3 washing → drying → offline
Below is a typical process table for processing 2 steel drums per minute.
Table 2 Process and structure table for processing 2 steel drums per minute
crafting processPre-deoiling
Degreasing
First wash
Second wash
Iron phosphating
Third wash
Operating temperature
60 ° C ± 5 ° C
60 ° C ± 5 ° C
Normal temperature
Normal temperature
50 °C ± °C
Normal temperature
Treatment fluid
PC-N364S
PC-N364S
PF-3456
Processing time (minutes)
1
2
1
1
2
1
Processing section length (m)
1.2
2.4
1.2
1.2
2.4
1.5
The tank body is made of 3mm thick stainless steel
long
1000
2000
1000
1000
2000
1000
width
1450
1450
1450
1450
1450
1450
high
980
980
980
980
980
980
Water pump ISG
65-160(I)A
65-160(I)
65-160(I)
65-160(I)
IHG65-160(I)
65-160(I)A
Electricity consumption KW
5.5
7.5
5.5
4.5
7.5
5.5
Infusion tube material
Carbon steel
Carbon steel
Carbon steel
Carbon steel
stainless steel
Carbon steel
Nozzle material
combination
combination
combination
combination
combination
combination
heating method
Hot water coil
Hot water coil
Hot water coil
control method
switch
switch
switch
There are two reasons why iron pretreatment is iron phosphating. A steel drum is a kind of packaging, and the coating is sufficiently treated with iron-based chemical treatment. The use of zinc phosphating in the pretreatment of the second steel drum is not only costly but also difficult to treat when phosphating.
(2) Steel drum vertical treatment
The so-called steel drum vertical pre-treatment equipment is the steel drum or barrel vertical type in the processing line for degreasing and phosphating.
Its advantages are:
(a) The effect is good because the flushing liquid flushing amount is enhanced when the inner wall of the barrel is treated;
(b) Because of the vertical cleaning, there is less stringing.
Second, steel barrel spraying equipment:
1. Simple spray booth: It consists of the water curtain panel and the grille of the spray booth. In the process of painting the steel drum, the spray mist is sprayed with the water paint mist in the water. There is also an uncollected paint mist that is drawn by the exhaust fan to the grille chamber behind the spray booth. When the gas mixed with the paint mist flows through the grille, the paint mist adheres to the grille plate, and the gas is pumped by the exhaust fan. Go outside.
2, high-purification spray booth: spray paint spray process in the steel drum using the water curtain water flow to collect the paint mist mixed in the water, or adhere to the water curtain board. The unpainted paint mist is pumped by the exhaust fan to the spray booth behind the spray booth. When the mist mixed with the gas is washed here, the paint mist mixed in the gas is washed, and finally the gas is pumped by the exhaust fan. The water vapor separator above the spray booth is separated from the water vapor by a water vapor separator. The cleaned gas after being separated is pumped to the outside by an air blower.
3. Steel drum rotating device: When the steel drum is painted, the steel drum has the following three rotation modes.
(a) Three-cylinder steel drum rotating machine;
(b) Fully enclosed four-cylinder steel drum rotating machine;
(c) Fully enclosed suspension high speed steel drum rotating machine.
Third, steel drum coating method
1. Steel drum coating
(a) Monochrome spraying of steel drum: the steel drum enters the spray booth and rotates under the action of the rotating machine. All the paint spray guns use a kind of paint to spray the steel drum so that the outer surface of the steel drum has only one color;
(b) Multi-color spraying of steel drum: the steel drum enters the spray booth and rotates under the action of the rotating machine. All the spray guns are separated according to the parts, and each part is sprayed with a paint to the specified part of the steel drum to coat the outer surface of the steel drum. Two or more colors;
2, steel barrel coating:
(a) Inner coating by pneumatic high-speed rotating cup: The pneumatic high-speed rotating cup is driven by the reciprocating machine to reciprocate up and down, and the inner body is coated for the barrel body.
(b) The inner coating is carried out by using a high-pressure airless spray gun: the high-pressure airless spray gun is driven up and down by the reciprocating machine, and the barrel body is rotated by the four-car wheel barrel rotating machine. The barrel rotates the spray gun up and down so that the inside of the barrel forms an inner coating, that is, the inner coating.
3. Selection and arrangement of steel barrel spraying machine, spray gun and nozzle:
(1), high pressure airless spraying machine selection
1 domestic airless paint pump and high pressure airless spray gun;
2 imported airless paint pump and high pressure airless spray gun.
(2) Selection of spray gun nozzle
1 The method of selecting the outer spray gun nozzle.
2 Comparison of advantages and disadvantages of domestic and imported spray gun nozzles.
(3) Arrangement of externally applied spray gun
(4) Paint heating, and heating method
The figure below shows the selection and arrangement of common spray gun nozzles.
Fourth, the drying and solidification of the steel barrel after painting
1, drying tunnel heating method
(1) Direct heating: The advantages are energy saving, and the disadvantages are easy to contaminate the outer surface of the steel drum and the inner surface of the inner barrel.
(2) Indirect heating: the advantage can ensure the outer surface of the steel drum and the inner surface of the inner barrel frame, and the shortcomings are wasteful of energy.
2. Selection and comparison of heating energy
(1), electric energy heating.
(2), fuel heating.
(3) Gas heating.
(4) Heating of solid fuel (coal).
3, hot air circulation method:
(1) Direct irradiation: Advantages The equipment is simple to manufacture, and the temperature in the drying tunnel is uneven, which affects the baking quality.
(2) Top delivery top return: The hot air is sent from the top of the drying tunnel, and then the air is returned from the top of the drying tunnel. In the case of multi-row baking, the temperature in the middle of the drying tunnel is easily uneven.
(3) Side delivery side return: the air is blown from the side of the drying tunnel, and the other side returns to the wind. The hot air passes through the drum in the transverse direction, and the temperature is easily ensured to be uniform.
(This article is a note for Mr. Yu from the lectures in the first phase of the barrel technical training class. For more information, please contact Mr. Yu.)
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