Preliminary study on the design of 100 liter export calcium carbide barrel

Preliminary study on the design of 100 liter export calcium carbide barrel

Lanzhou Co., Ltd.

The key to the export of calcium carbide is packaging O. The quality of packaging directly affects the protection and safety of calcium carbide during storage and transportation. Calcium carbide is a dangerous chemical. The calcium carbide produces acetylene gas in contact with water. The acetylene gas is active and easy to burn and explode. The contact of calcium carbide with water produces acetylene gas, which seriously affects the quality of calcium carbide, that is, reduces the amount of gas generated by calcium carbide. Therefore, it is important to ensure the quality of the sealing of the calcium carbide drum. The lessons in this regard are also painful. Due to the poor quality of the sealing of the calcium carbide barrels, serious quality accidents were caused in the export of calcium carbide to India and other countries, and the economic claims were made, which affected China's foreign trade reputation. In the history of international shipping, due to the poor quality of the calcium carbide barrels, the explosion occurred after the calcium carbide met the water, causing the ship to sink and die. There is no precedent.

Gansu Province is a province that has good conditions for the production of calcium carbide. The Liujiaxia Hydropower Station in the country is located near Lanzhou, providing sufficient electricity for the production of calcium carbide. Calcium carbide raw materials are richer in limestone. For many years, the issue of calcium carbide export packaging has not been resolved, and calcium carbide has not been directly packaged for export.

In July 1987, the Lanzhou Barrel Factory finally successfully produced the TDY100-440/0.8 type 100L export calcium carbide barrel. According to the inspection by the State Administration of Commodity Inspection, all technical indicators of calcium carbide barrels have met the standard requirements and have been produced in batches. It is exported to Singapore, Japan, Malaysia, Pakistan and other countries with its packaging calcium carbide. User feedback performance is good.

The main points of the process design are summarized as follows:

First, refine and optimize the main parameters in the "Standard for Exporting Calcium Packing Barrels (Interim Measures)" (hereinafter referred to as (Interim Standard)). To lay the foundation for process design and high quality and low consumption of products.

We conducted research and experiments and carefully studied (interim standards). Found (temporary standard) its main parameters: barrel inner diameter, barrel effective height and barrel size upper and lower deviation range. Choosing a bad size can affect product quality or waste material.

(Interim standard): 100L calcium carbide barrel, inner diameter is φ450±lOmm, barrel body effective height is 700±20mm, barrel diameter is more than 200mm. According to its regulations: the inner diameter of the calcium carbide barrel should be within 440 ~ 460mm, and the effective height of the barrel is within the range of 680-720mm. After calculation, the theoretical capacity of the barrel is up to 119.65L, the minimum is 103.39L, and the up and down deviation is 16.26L. In this way, the implementation of the same (interim standard) results in different sizes, large differences in capacity, and inconvenient uniform assessment; on the other hand, if the (upper-standard) upper or intermediate size is used, a 0.8×1000×2000 The steel plate can't make a calcium carbide bucket. Our factory found that many barrel brother units, in order to ensure the cost of the packaging barrel, actually determined the barrel diameter to be less than (temporary standard) size, not meeting the requirements of (provisional standards).

We have repeatedly verified the key parameters of the barrel diameter, the effective height of the barrel and the barrel mouth, and made it preferable to make it more precise. Finally, the inner diameter of the 1OOL calcium carbide barrel is determined to be φ440±2mm (the actual mold processing size is φ440+0.63mm). The effective height is 685 ± 3mm. The barrel mouth is set to φ215+0.29mm. This size meets (interim standards) and guarantees quality, improving the sealing and durability of the double crimp. This size also saves material, and all the steel plates are packed in a barrel, and there is a bucket and a surplus material (see Figure 1). The material utilization rate can reach 84.6%, which can save 9.6% steel plate compared with the original domestic calcium carbide barrel.

Figure 1 100L calcium carbide barrel discharge diagram

We also supplement the structural dimensions that are not valid in the (interim standard), such as the curling edge, the bottom of the bucket and the depth of the bucket top, the size of the barrel mouth, the nitrogen filling port, the venting port and the ring ribs, and the position. (temporary standard).

Second, the use of advanced technology, the use of composite molds, improve work efficiency and ensure quality.

A high-quality product, first, we must have a good product standard, product design should be advanced, scientific use performance is good, and second, there must be a practical and reliable process to achieve product design ideas to ensure product performance.

We carry out the tenet of “Quality First, High Efficiency, Low Consumption and Guaranteed Benefit” in the process design of 100L export calcium carbide barrel. Our specific methods mainly include the following:

(1) Make full use of materials on the basis of the preferred barrel diameter. Deepening and relaxing the size of the bottom of the bucket and the top of the bucket create conditions for assembling the crimp and ensure the quality of the seal of the bucket.

According to the experience of crimping the 200L closed steel drum at home and abroad: the width of the crimping edge is relatively small compared with the bottom of the bucket or the top of the bucket. China's 200L steel drum GB 325-84 regulations: the bottom of the barrel or the top of the barrel is 19 ± 1mm. In practice, it is generally reflected that this size is small. Japanese and American barrel bottoms or barrel tops have a depth of 25mm. In order to improve the quality of double hemming, China's steel drum manufacturing industry has generally increased the size of the bottom of the barrel or the top of the barrel, from φ637mm to φ642mm, so that the depth is as large as possible. Thus, the double bead width is 13 mm, the bottom of the bucket or the top of the bucket is 20 mm, and the ratio of the two dimensions is 6.5:10. After many years of practice, the effect is good, the sealing performance can be guaranteed, and the collision is not easy to leak.

According to this, in order to determine the size of the outlet of the calcium carbide barrel or the top of the barrel, in order to make full use of the material, a two-piece material discharge method (see Fig. 1) is adopted, so that the blanking size is set to φ500 mm. In this way, on the 1m wide material, two barrel bottoms and top materials of φ500mm can be dropped. This is rare in the national barrel industry. In addition, there is a process edge size (2 mm from the edge and 6 mm between the two). The crimping width is 9.5mm and the bottom top depth is 15mm. The ratio of the two is 6.32:10. The ratio is less than the ratio of 6.5:10 for the 200L steel drum. The use performance is better, which ensures the double-hem sealing performance.

In recent years, the quality of dangerous goods packaging has become more stringent. Each calcium carbide barrel production plant feels that the double crimping structure has certain weaknesses, it is not resistant to collision, and it is difficult to ensure the sealing quality during storage and transportation. Therefore, when formulating the national standard for "stone drum", the barrel diameter φ450±10 specified in the original (provisional standard) was changed to φ430±2. In this way, the top edge width of the bottom of the bucket can be increased by 5 mm. It is convenient to adopt the international advanced technology of the seven-layer round crimping, thereby improving the sealing quality of the calcium carbide bucket.

(2) Strictly control the ratio of the size of the mouth and the size of the flange to the width of the mouth of the barrel to ensure the quality of the seal.

The barrel opening we designed is φ215+0.29mm, the width of the barrel opening is 6±0.5mm, the diameter of the barrel cover is φ215-0.29mm, the width of the side is 14+1mm, the size of the barrel edge and the edge of the barrel The ratio of width is 3:7 (see Figure 2). This value is our empirical data summarizing domestic and foreign steel drums. We designed the barrel mouth to match the size and performance.

Figure 2 barrel structure

(3) The sealing of the nitrogen filling port and the venting port adopts a new type of gasket. Our factory uses sealing gasket made of acid and alkali resistant medium hardness rubber. This gasket meets the requirements of HG4-330-66 "Rectangular Rubber Washer" to ensure the sealing of the nitrogen filling port and the venting port. In order to make the sealing pad not easy to fall off when using it, the M10 bolt is not used, and the washer with the do=8 and the inner diameter of φ9 is used to tighten the bolt. In order to avoid the screwing of the rubber pad when the screw is pressed, the sealing effect is affected by the deformation of the rubber pad. We add a standard metal washer diameter d=10.5mm and a thickness S=2mm on the rubber pad. In this way, when the bolt is screwed, the bolt directly contacts the metal washer and rubs, and the seal is not affected by the deformation of the rubber pad. See Figure 3 for details.

Figure 3 Inflatable port and vent nut fixed shell and barrel vertex welding

(4) The airtight test method is used to check the sealing quality of the calcium carbide drum.

(5) The welding of the M10 nut in the top nitrogen filling port and the venting port and the inner surface of the top of the barrel adopts a new process to ensure the quality and improve the work efficiency.

The welding of the calcium carbide barrel nut and the top of the barrel is generally performed by manual arc welding. This method is easy to burn through the top of the bucket and deform it. At the same time, the nut is easily misplaced during welding. Innovatively addressed this issue. Due to the large thickness of the two weldments, the spot welding process cannot be used. Therefore, we designed a special die for blanking and punching around the three-nozzle. Using this mold, a nut fixing shell that matches the nut is punched out on the scrap of the product. The bottom plane of the periphery of the casing has three projections. After the nut is pressed into the housing, on the spot welding machine with the positioning device, the three-nozzle of the nut casing is directly welded to the inner plane of the top of the barrel (see Fig. 3). Since the thickness of the two weldments is uniform and the weld spot area is small, the current density is high and the steel plate is melted. Originally used 31KVA spot welding machine, this time welding three points using 25KVA spot welding machine, in addition to saving energy, improve work efficiency 3 times. The welding quality is flat, firm and accurate. After the 3kgf-M torque test, the weldment does not fall off. This is a relatively advanced welding process. This process is rarely seen in domestic production of steel drums of more than 50L. However, in the production of the bucket (convenient barrel), the barrel ear is welded to the barrel body, and this method is widely used. Our factory has used this process to produce more than 100,000 exporting calcium carbide barrels. Due to certain problems in our mold manufacturing technology and the poor degreasing and rust removal of the material surface, the welding quality is sometimes not stable enough, and some nuts fall off when the bolt is screwed on. To this end, we have improved the process of fixing the nut to the top of the bucket. The nut is reworked and fixed on the opposite side of the barrel top nut assembly. (See Figure 4) This method is more reliable, but the processing nut is more labor-intensive, and it is necessary to install a sealing ring on the outer edge of the processed nut to ensure the sealing quality of the nitrogen filling port and the venting port.

Figure 4: The inflation port and the vent nut are pressed against the top of the barrel.

(6) The use of composite die, in the process and tooling design, the quality, to benefit.

The processing of parts for exporting calcium carbide barrels is inseparable from stamping dies. However, the stamping process and the design of the mold directly affect the economic benefits and product quality.

Seven parts, such as the bottom of the barrel, the top of the bucket, the lid of the bucket, and the shell of the nut, are produced according to the original process, and 18 sets of molds are required. With a composite die, only seven sets of molds can be used to complete the machining of seven parts. For example, a set of molds for blanking, stretching and pressing ring at the bottom of the barrel; punching, flanging, flushing and venting of the top of the barrel can be completed by one stamping. The use of composite molds not only has high production efficiency, but also improves work efficiency. ? Times, saving manpower, power and equipment, and due to one-time processing, the workpiece-related dimensions are accurate and the product quality is improved.

(7) Guarantee quality and increase necessary processes.

Since the outer surface of the steel drum in our factory is not sprayed with primer, the quality of the coating is problematic. We are more cautious in the design of the outer surface of the export barrel. It adopts manual degreasing and derusting; it is made of iron-alkali red primer; it has good weathering alkyd topcoat. Spray mark, text, number quickly dry Q04-2 white nitro enamel. This increases the number of processes, increases materials, man-hours and costs, but the quality of steel drum coating is much higher than the original. Through the above practices, I solved the seals of three (barrel, nitrogen filling and venting), three knots (the barrel and the bottom of the barrel, the top of the barrel and the seam of the barrel). The quality of the surface of the barrel. In the whole process of process design, we all pay attention to quality, reduce consumption, improve work efficiency and increase economic benefits.

Due to the advanced technology and tooling, the barrel is round and smooth, the structure is reasonable and compact, and meets the technical requirements of (interim standard). The airtight test is 0.3Kgf/cm2, the water pressure test is IKgf/cm2, and the drop test is 1.2 meters. Leakage, performance test is required by the state commodity inspection. The packaging unit and the foreign company have good performance.

Compared with the domestically produced domestic calcium carbide barrels, the barrels can save 500 tons of calcium carbide in one year due to the reliable quality of the seals, which can produce 50,000 barrels per year and reduce the loss of calcium carbide by 10% per barrel. That is to reduce the loss of more than 300,000 yuan.

Although we have made certain achievements in the process of developing and exporting calcium carbide barrels, we have hoped that our peers will correct them because of our limited technical level and many quality links.

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