Development of steel drum coating equipment

In the past 30 years of reform and opening up, the technology and equipment of the barrel making industry in China have been greatly developed. Especially during the past 20 years, the coating and painting equipment for steel drums has been continuously researched and reconstructed, and a well-developed steel drum coating system has been formed. . Nowadays, the steel drum coating technology led by the Beijing Fuheng Coating Equipment Promotion Center has always been at the leading position in China.

First, the treatment of steel barrel coating

1. Why steel drums must be pretreated

Pretreatment of steel drums is an important basic process. It has an important influence 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 coating of steel drums, various treatments were found to be used, and the quality of the coating film after coating was very different. Poor quality treatment before coating or no pre-treatment, even if coated with advanced paint, can not get a good coating quality. It is too late to think of pre-treatment of steel drums when there is a quality problem in the coating of steel drums. It is therefore suggested that steel drum manufacturers should pay attention to the pre-treatment of steel drums.

The following are the experimental results of a two-year steel plate that was treated with different treatments before coating and exposed to natural conditions in the south.

2, the pre-processing method

Mechanical and chemical treatments are generally used. The so-called mechanical treatment is the use of sandpaper to remove rust, wipe oil on the surface of steel drums and other dirt; the so-called chemical treatment is to use chemical liquid to remove oil and rust on the surface of the drum, and then use chemical The liquid makes a phosphate film on the surface of the drum. Among them, steel barrels are pre-treated by mechanical methods, and the quality is not stable. Take a piece of cloth to wipe the surface of the drum and other dirt. When the cloth is rubbed before several steel drums are effective, but the effect is poor afterwards, especially the last few may be worse than not rubbing. Because the oil on the surface of the steel drum has been stuck on the rags when rubbing the front steel drums, these oils are sticking to the rubbing steel drums. For this reason, the quality of the steel drums must be good or chemically treated.

3. Introduction of the latest chemical processing equipment designed by our company

(1) Horizontal steel drum treatment:

The so-called steel drum horizontal pretreatment equipment is a steel drum or barrel horizontally deoiled and phosphatized in the processing line (the new cold-rolled steel plate is generally used now, so no rust removal is required).

crafting process:

Pre-degreasing → degreasing → 1 washing → 2 washing → iron phosphating → 3 washing → drying → offline

The following is a typical process table for handling 2 steel drums per minute.

Table 2 Processing Process and Structure of 2 Steel Drums per Minute

There are two reasons why steel drum pretreatment uses iron phosphating. A steel drum is a kind of packaging, and its coating is sufficient for chemical treatment with iron. The use of zinc phosphating in the pretreatment of the second steel drum is not only costly but also difficult to treat due to slagging during phosphating.

(2) Vertical treatment of steel drums

The so-called steel drum vertical pretreatment equipment is a steel drum or barrel vertical type that performs degreasing and phosphating in the treatment line.

Its advantages are:

(a) The effectiveness of the flushing liquid flushing is enhanced as the inner wall of the barrel is treated;

(b) Due to the vertical cleaning, there is less string liquid.

Second, drum spraying equipment:

1. Simple spray booth: It consists of spray booth housing water curtain and grille. During the paint spraying process of the steel drum, a water curtain is used to recover the gas paint mist in the water. In addition, the uncollected paint mist is drawn by the exhaust fan to the grill room behind the spray booth. When the mist mixed gas flows through the grill plate, the paint mist adheres to the grill plate, and the gas is pumped by the exhaust fan. To the outdoors.

2. High-purification spray booth: Overspray in the process of steel drum spray The water mist in the spray curtain collects the gas mist in the water, or adheres to the water curtain. In addition, the uncollected paint mist is drawn by the exhaust fan to the spray booth behind the spray booth. When the gas mixed with mist passes through the shower, the paint mist mixed in the gas is washed cleanly, and finally the gas is pumped by the exhaust fan. At the upper part of the spray booth, a steam separator separates it from the water vapor through a steam separator. The separated clean air is pumped outdoors by an exhaust fan.

3. Drum rotation device: When the steel drum is painted, there are three types of rotation of the steel drum.

(a) Three-card wheel drum rotary machine;

(b) Fully enclosed four-card wheel drum rotary machine;

(c) Fully enclosed high speed steel drum rotary machine.

Three, steel drum coating method

1、Drum coating

(a) Monochrome spraying of steel drums: steel drums enter the spray booth and the drums rotate under the action of a rotary machine. All paint spray guns use a paint to spray the steel drums so that the drums have only one color;

(b) Multi-color spraying of steel drums: Steel drums enter the spray booth and the drum rotates under the effect of a rotary machine. All spray guns are separated by a part and a paint is applied to each part of the steel drum to spray the specified part of the drum to coat the outer surface of the drum. Two or more colors;

2, drum coating:

(a) Internal coating with a pneumatic high-speed rotary cup: A pneumatic high-speed rotary cup is driven by a reciprocator to reciprocate up and down to paint the barrel.

(b) High-pressure airless spray gun for internal coating: The high-pressure airless spray gun is driven by the reciprocator to reciprocate up and down, and the barrel body is rotated by a four-card wheel barrel rotary machine. The barrel body rotates the spray gun up and down so that the inner layer of the barrel body forms an inner coating, namely inner coating.

3, drum spraying machine, spray gun and nozzle selection and layout:

(1) Selection of high pressure airless sprayer

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 Nozzles

1 spray gun nozzle selection method.

2 Comparison of advantages and disadvantages of domestic and imported spray gun nozzles.

(3) Arrangement of spray gun

(4) Paint heating, and heating method

The following figure shows the selection and arrangement of nozzles for common spray guns.

IV. Drying and curing of steel barrels after painting

1, drying the way of heating

(1) Direct heating: Advantages Save energy, and the disadvantages easily contaminate the outer surface of the drum and the inner surface of the inner barrel frame.

(2) Indirect heating: The advantages can guarantee the outer surface of the steel drum and the inner surface of the inner coating barrel frame, which is a disadvantage of energy waste.

2. Selection and comparison of heating energy

(1) Electric 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 disadvantages of uneven temperature in the drying tunnel affect the baking quality.

(2) Top delivery top return: Hot air is sent from the top of the drying tunnel, and the air is returned from the top of the drying tunnel. When baking in multiple rows, the temperature in the middle of the drying tunnel tends to be uneven.

(3) Side-feeding side-return: blowing air from the side of the drying tunnel and returning air from the other side. Hot air is horizontally passed through the steel drums and the temperature is easily ensured evenly.