1. Overview of the barrel making industry
The common characteristic of American barrel companies is that the product varieties are relatively single, the annual output is large, and there are fewer factory personnel. The typical five companies are shown in Table 1.
Factory name
product
Yield
Production line form
Number of people
Factory area
Van Leer
200 liter barrel
1.4 million/year
Vertical layout
240
29768 m 2
Medium bucket
600,000/year
Convenient bucket
3 million/year
Triller
200 liter barrel
1.1 million/year
Vertical layout
60
Rusll Standly
200 liter barrel
650,000/year
Horizontal layout
100
BW Norton
5 gallon bucket
3000/hour
47
5500 m 2
Meyers,Richmond
200 liter barrel
4600/hour
140
6048 m 2
Travel Trilla
200 liter barrel
700,000/year
48
7116 m 2
Meyers, Los Angels
5 gallon bucket
200 liter barrel
51
6528 m 2
2, barrel making process
(1) Steel plate cutting US barrel mills use cold-rolled coils and unwinding equipment. The unwinding unit consists of uncoiler, straightener, measuring and guiding system and shearing machine to uncoil, level and cut the coils. The precision of the barrel plate after shearing requires a diagonal error of ±1 mm.
The unwinding unit of the bottom lid is connected in series with the press machine.
(2) The edge-sheared steel plate enters the abrasive machine through an automatic feeder. The edge grinding efficiency is generally not very good, but since it is a cold-rolled steel plate, the problem is not large. The latest US edging machine steel plate conveying speed is stepless speed regulation, in addition the speed of the grinding wheel is adjustable (2000 ~ 4000 rev / min, the application of speed motor), also equipped with 300 sheets per mill can be automatically adjusted The grinding wheel feeds 3 inches (0.076 mm) of the device.
Grinding wheels are generally 1 inch wide and are 2 inches wide when hot rolled plate is milled. The more special is the use of a 4 inch wide abrasive wheel with an emery cloth when grinding galvanized steel.
(3) Welds Weld seams in steel drums in the United States have generally adopted automatic seam welding machines, and most of them are manufactured by CARANDO of the United States. The automatic seam welding machine is composed of a roll, a barrel, a welding, and an equalizing mechanism. The roll is still a three-roller. The roll-formed plate is placed on the upper part due to the baffle and is sent to the welding plate after being sent to the barrel chain. At the wheel, the two parts of the electrode wheel passing through the Z-shaped slot are connected to the two stages of the transformer. After the welding, the weld is still in the red hot state, that is, through the flattening roller, so that the weld is smooth and dense.
There are two kinds of DC and AC welding machines, DC welding power factor is high, more power, but the cooling requirements are higher; AC welding power factor is low, more power, but the cooling requirements are lower. There are two types of welding machine barrels, one for the funnel shape, with 3 to 6 large concave wheel positioning, suitable for a single barrel type of production, if you replace the variety you need to replace the wheel, more time-consuming, while requiring the barrel Body plate size is also more stringent. The other is a pleated type. The barrel body is fixed with two rows of oblique wheels and two pairs of pressure rollers. The feature is that the adjustment is more convenient when the diameter changes. The disadvantage is that if the adjustment is not good (the top of the inclined wheel is not true), it is easy to make Too small to form waste products.
CARANDO's seam welding machines have adopted secondary rectifying power supply methods for power supply, achieving better electrical efficiency and stable welding current. As for the three-phase power supply products, it is reported that due to the low power efficiency of the power supply, there is currently no mature product.
The main technical features of the 1424-1 automatic seam welding machine produced by CARANDO are: power supply mode: single phase AC, power: 200 kVA, productivity: 900 pcs/hr, welded steel plate thickness: 0.6-1.5 mm. For other types of automatic seam welding machines of this company, the available welding parameters are: secondary current of 20,000 amps, 4.97 to 8.7 volts at secondary voltage AC, and 2.93 to 5 volts at DC.
In addition, the company also produces 1200 high-speed welders per hour, using a single-phase secondary rectifier power supply.
(4). Flanging and ribbing flanging machine adopts die extrusion method, with uniform flanging, high power, and better quality than rolling method. The rib reinforcement machine also uses a tapered structure to increase the ribs, and the two ribs have swelled. Both machines are operated by mechanical (eccentricity, connecting rods) and are easy to maintain.
U.S. VANLEER and TRILL use CNC vertical forming units. It is a new multi-position special combination machine. The outstanding advantages of this unit are its high level of automation and process adaptability. It is controlled by the programmable controller of ALLEN-BRADLEY, USA. Modifying, adjusting process parameters and some product specifications can be achieved in just a few seconds by changing the control program.
In addition, in the design of the vertical forming unit, the conventional frame is eliminated and a more flexible transmission mechanism is adopted. For example, a DC servo motor, a ball screw, and a sheave rod mechanism greatly reduce the inertia of the device and can thus be compared. With low energy consumption and higher operating speed, the average production speed of each station can reach the level of 800 steel barrels per hour. At the same time, the transfer between workstations has changed the traditional way of chain-type transportation of horizontal production lines, adopting a rigid support-type conveyor belt, shortening the production line, greatly improving the positioning accuracy, and combining the process of extrusion flanging and edging. Get high-quality barrel frame flanges, providing a guarantee for high-quality seals.
(5) Sealing and sealing machine adopts horizontal double action. The coil seal still uses two wheels. The materials of the wheel and disk are alloy steel, which is used after heat treatment and grinding. The fillers at the roll seals are all rubber-based emulsifying fillers. Most fillers are injected at the time of sealing. Pre-spraying is also used. After drying, they are sealed. During sealing, coolant is sprayed on the roll-up wheel at the same time to prolong the service life.
In the United States, standard 200-liter steel drums used for the packaging of liquid dangerous goods, such as chemicals, are generally no longer double-sealed. Instead, they are mainly circular crimps with inconspicuous stress concentrations. Due to the superior mechanical structure of this type of crimping, it has strong impact resistance. When it was visited by TRILL company in Chicago, it performed a 45° drop test for us. It was highly calibrated to 2.4 meters and triple circular crimped. No damage was found in the steel drums.
The circular hemming used in the United States is based on patented triple hemming technology, which uses a bottom and cover pre-crimping. Pre-spray seal packing process. The bottom and cover pre-crimping process is to pre-roll a small arc-shaped small edge of a bottom cover of a drum on a device, and then to wind the drum into a bucket on a sealing machine.
Of course, this kind of crimping requires high flange size of the barrel body, and the general width error should be controlled within ±0.25 mm. This is one of the important reasons why extrusion is generally used in foreign countries to form a flanging machine.
(6) There is no difference between the leak test and domestic use. Only the horizontal ends are threaded, and the length of the test can be adjusted to achieve alignment. This has not been used in China.
(7) Surface treatment (degreasing, phosphating) After the barrel body and the bottom cover are formed, all plants are surface-treated, and all of them have phosphating parts. The equipment is in tunnel type, and is generally degreasing, washing, phosphating. , washing, drying and other parts, degreasing, phosphating, washing are used spray type, transmission is a single row, chain drive. The barrel and lid are handled centrally and separately.
The drying mode is the same as the drying mode of spraying on the inner and outer surfaces. Generally, the drying length is equal to the length of degreasing, phosphating, and washing, and the relevant parameters of the surface treatment process are shown in Table 2.
Table 2
Process
temperature
speed
Degreasing
160°F (71°C)
28?眨?.53 meters)/min
Washing
12?眨?.66m)/min
Phosphating
140°F (60°C)
32?眨?75m)/min
Washing
12?眨?.66m)/min
Washing
140°F (60°C)
18???.49 meters)/min.
drying
(8). Inner surface spraying All spraying equipments are horizontal and vertical. There is not much difference between horizontal and domestic methods. The vertical type has not been seen in the country. Its characteristic is to reduce the change of the barrel position. The method is that the gripper lifts the bucket in place and the spraying finishes during the round trip. Spraying is an airless spray. In addition, it is more common to have two or two baking or two baking and two baking. Most of the drying uses natural gas and is accompanied by hot air circulation. This method has a good drying effect. There is also a factory that uses the gas burning open flame heating method. This method is also used in France. It is estimated that the thermal efficiency is not as high as the hot air circulation. The drying oven is not See the use of air curtains, presumably using hot air circulation, will effectively prevent heat dissipation.
Drying furnace design temperature 350 ~ 450 °F (176 ~ 232 °C), baking time 15 minutes.
(9) The exterior surface painting adopts the airless spraying method, and all the equipments are all horizontal spraying machines. The difference between this machine and the domestic mechanical spraying machine is that many spray guns are used. The barrel body is provided with three spray guns, and each side of the barrel cover There are two, more spray guns can shorten the spraying time.
The outer surface of the drying oven can be used to dry at least two rows of barrels, so that the heat consumption of the barrel can be reduced. The drying method and the inner surface of the drying oven are the same. The drying temperature for the polyester paint is 350°F ( 176°C), time 10 minutes.
(10) The Indian Railway VANLEER factory has three printing lines, which are large, medium and small barrels. The printing iron in 200 litre barrels is rare. Iron printing machine is color printing, so the barrel after production is very delicate, the printed iron plate, after welding, forming is still not off, after the surface treatment has no effect, of course, the finished product barrel also has a weld coating process.
3, the use of materials
The American National Standard (ANSI MH2.1-1997) states that the ordinary 200-liter steel drum bottom cover and barrel body adopt different grade steel plates respectively. The bottom cover is class 20 (above 0.823 mm) and the barrel body is class 18 (above 1.09 mm). This is a standard established from the concept of isokinetic strength in mechanics. It has great economic significance in the use of materials. Save 6.6% on steel.
In addition, the bottom cover blanking adopts a wide web and is arranged in a staggered manner, which greatly reduces the waste of scrap. It can save about 5.4% of the steel plate compared to the original single-row arrangement of the narrow web.
4, the coil assembly
Assembling the coils of closed steel drums, the domestic factories are generally completed by the following three processes: 1. Punching; 2. Hole stretching; 3. Locking. In the United States, we saw a special assembly mold provided by the American flange company to the barrel factory, using a process to complete the assembly of large and small coils. The actual use cases seen by Chicago Quele and the Houston-based Rashey Stray Company are very satisfying.
5, the application of filler
There are two types of fillers:
(1) 740HS Foamed Filler, produced by DAREX, with molding conditions of 110°C for 13 minutes; each bottom cap has a dosage of 12.5 grams, high-pressure airless coating, and bottom cover autorotation speed of 0.7 second/ turn.
Such fillers used by companies such as American Miles and Quele have formed an annular sealing gasket at the edge of the pre-rolling of the bottom cover of the barrel to ensure the anti-leakage performance of the barrel.
(2) Latex fillers based on synthetic rubber, grade DA-REX60, manufactured by WRGRACE, with gelling conditions at room temperature. According to the results of the inspection of the barrels on site, the success rate of sealing barrels was above 99.9%, indicating that the above two fillers have mature experience in application in the United States and their technical performance can be trusted.