Application of one-way exhaust and aeration technology in steel drum packaging
Application of one-way exhaust and aeration technology in steel drum packaging
Text / Yang Wenliang
With the increase in the demand for steel drum packaging and the acceleration of the development of the barrel industry, people are paying more and more attention to the packaging quality of goods. Various inflatable packaging, vacuum packaging and exhaust packaging are increasingly favored by the barrel industry and steel drum users. In recent years, the application of one-way inflation and exhaust technology in steel drum packaging has become more and more widespread, and there has been a combination of a one-way valve and a steel drum package, which can meet the special requirements of the packaged object. Such functions as automatic exhaust, one-way inflation or pumping during storage or transportation bring great convenience to the use of steel drums.
1 automatic exhaust steel drum
1.1 Principle and structure
The automatic exhaust steel drum is mainly driven by a one-way valve mounted on a steel drum. The one-way valve is composed of a valve body, a valve cover and a gasket. The valve body and the valve cover embed the gasket in the middle to balance the pressure inside and outside the steel drum and block the outside air from entering the container. See Figure 1 for the basic structure. The check valve is mounted on a steel drum container to provide automatic venting of the steel drum. When the internal pressure of the packaging steel drum is stronger than the maximum pressure value allowed by the steel drum, the sealing gasket of the one-way valve is automatically opened under the pressure difference between the inside and outside of the steel drum to release the gas in the container and reduce the pressure inside the container, thereby avoiding packaging. The steel drum swells and leaks or explodes. At the same time, the external gas cannot enter the inside of the container due to the unidirectional barrier property of the check valve, thereby ensuring that the quality of the contents is not impaired.
Figure 1 Schematic diagram of a common one-way exhaust valve
1.2 Application of automatic exhaust valve
For packaging steel drums of dangerous goods, in general, the tighter the sealing of the packaging, the better, especially for gas-prone, volatile dangerous goods, etc., to prevent leakage. However, due to the special nature of dangerous goods, the packaging of some dangerous goods cannot be completely sealed. For example, calcium carbide (calcium carbide) will produce acetylene in the case of moisture, and acetylene will explode if it collides with the hard calcium carbide block or steel barrel wall, so the calcium carbide packaging barrel can not be sealed tightly. Small hole. A check valve device with automatic exhaust function can be installed on the calcium carbide drum to avoid explosion due to moisture weathering of the calcium carbide. The device has the characteristics of being easy to fall off, safe and reliable, easy to install, easy to process, and low in cost, and has a good market development prospect.
As shown in Figure 2, it is a national standard export stone bucket bucket physical map, with a filling port and an exhaust port on the top of the barrel. The large mouth in the middle is the filling port. After the calcium carbide is filled, it is sealed with a lid. The calcium carbide barrel used for export generally adopts the type of crimp sealing, which cannot be recovered after one-time opening; the calcium carbide barrel used for domestic sales generally adopts the sealing method of bolt and washer, and can be repeatedly opened. The small holes on both sides of the intermediate packing hole are vent holes, which are nut holes, and can be installed with an exhaust valve or a sealing bolt.
Figure 2 Physical image of calcium carbide packaging steel drum
In general, the way of operation is this. After the first step is to fill the calcium carbide, the intermediate filling hole is covered with a lid to seal. The second step is to install an exhaust valve for the inner stone of the calcium carbide barrel, which can be installed with a gas venting valve on one of the venting holes and a sealing bolt on the other venting hole; the calcium carbide barrel for the outlet can be ventilated from one of the The hole is filled with helium gas, air is exhausted from the other vent hole, and then both vent holes are fitted with sealing bolts.
Figure 3 shows the exhaust valve commonly used on calcium carbide drums, which is installed on the small screw holes on the top of the bucket.
Figure 3 Exhaust valve for steel drum
The structure and principle of the exhaust valve are shown in Figure 4, and the working process and principle are as follows. When the pressure in the barrel is greater than the set pressure, the gas pressure in the barrel enters the passage of the exhaust valve through the valve port, pushes the exhaust valve to compress the spring, and moves the exhaust flat pad 7 to the left, thus opening the ventilation flat pad 4 A seal formed with the exhaust flat pad 7. The gas is discharged through a small vent hole on the valve body 3. When the external atmospheric pressure of the pressure in the barrel is balanced, the spring is reset, and the vent flat pad 4 and the exhaust valve flat pad 7 are tightly sealed to form a seal.
1-spring; 2-pressure regulating valve cover; 3-valve body; 4-ventilating flat pad;
5-rubber seal; 6-epoxy glue; 7-vent valve flat pad
Figure 4 Structure and schematic of the exhaust valve
2 vacuum or pneumatic packaging steel drum
2.1 Principle and structure
The vacuum-packed steel drum mainly discharges the gas in the packaging container through a closure on the steel drum to reduce the gas in the packaging container. The utility model is matched with an air suction device, an automatic air suction device or an electric air suction pump, and the valve cover is connected with the outer end device to achieve the effect that the air in the packaging barrel is reduced to a certain degree of vacuum. It can also extract the humid air in the barrel, keep the barrel dry, and achieve a certain degree of vacuum to prevent rust in the barrel. Figure 5 is a physical outline of a common vacuum pump.
Figure 5 physical drawing of the air pump
The air-filled steel drum is mainly made up of a nitrogen generator or a nitrogen tank, and the drum is filled with nitrogen gas from the drum sealer to prevent rust in the barrel or the cargo reacting with the air. It is also possible to fill the barrel with dry air and replace the humid air in the barrel to achieve the anti-rust effect in the barrel. Figure 6 is a schematic diagram of a conventional nitrogen generator. Figure 7 is a physical outline of a conventional nitrogen generator.
Figure 6 Schematic diagram of nitrogen generator system
Figure 7 Nitrogen machine physical outline
2.2 Application of vacuum and pneumatic packaging steel drums
At present, vacuum-packed steel drums are mainly used in steel drum production and steel drum filling.
The steel drum manufacturer thoroughly cleans and phosphatizes the steel drum before the steel drum is painted, so that the inside of the steel drum is very clean, but due to the production environment and the like, a large amount of humid air may be stored inside the steel drum. These humid air can easily rust if there is no protection from grease on the inner surface of the barrel, which reduces the cleanliness of the steel drum and affects the use of the steel drum. In order to make the steel drums officially used after production, during this time, the inside of the steel drum is no longer rusted, and many companies have adopted the method of vacuuming the steel drum. The production process generally uses a vacuum machine to extract the humid air in the barrel, and then fills the barrel with dry air. The higher enterprise is required to fill a part of the nitrogen into the barrel to prevent the air from entering the barrel again. To the rust prevention effect.
Steel drum filling users also extract air from the barrel and fill it with nitrogen during filling. The main purpose is to prevent the air in the barrel from oxidizing with the contents. For example, in order to prevent the airborne stone from being exposed to air in the barrel, the acetylene gas may be exposed to the danger of explosion due to the reaction of humid air. After the canning, the air inside the barrel is firstly taken to make the inside of the barrel into a vacuum, and then the barrel is filled with nitrogen. . In the packaging of dangerous goods, there are many such packages, such as sodium metal, sponge titanium, yellow phosphorus, etc., which can be used to isolate air.
3 Conclusion
The one-way exhaust or air-filled packaging utilizes the one-way valve to have a one-way gas passing characteristic, thereby solving the contradiction that the gas inside the packaging steel drum is exchanged in one direction without being affected by the external gas component. One-way exhaust or air-filled packaging reduces the corrosion of steel drums and the oxidative deterioration of the steel, which brings great convenience to the application of steel drums and improves the application range of steel drums. At the same time, it also saves a lot of resources. The society has brought greater economic benefits.
The vacuum and air-packing of steel drums is a new process for the production of steel drums in recent years. It is a major advancement in the direction of high-cleaning steel drums. At present, an important method for the production of high-clean steel drums has been gradually formed.
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