As one-time foaming plastic snack cartons were gradually discontinued, one of its alternatives, pulp molded snack cartons, mushroomed into the market. At present, there are nearly 100 factories that manufacture pulp molded tableware in China, and there are still rising trends. The national wind also has some machinery industries that produce paper cutlery box molding production lines.
The raw materials used for pulp molded tableware are pulp and a small amount of chemical additives. The production method is applied wet molding, and then gradually remove the moisture. This production method is quite similar to the production method of papermaking. We can think of it as a branch derived from the paper industry. The difference between the production process of the pulp molded tableware and the conventional paper production process is that the paper produced by the paper machine is a flat surface, and the snack box produced by the pulp molding production line is a container. Therefore, the former is easier to achieve continuous production and automation. The latter has so far no fully automated production line put into operation.
The production of molded paper cutlery boxes has only four or five years of history in China and is now in the early stages of development. Due to the incomplete maturity of the process, its current cost is high, which is an unfavorable factor constraining large-scale entry into the market. At present, paper meal boxes have to sacrifice the market on a large scale. They also depend on further improving the production process, reducing costs and improving quality.
There are two main reasons for the high cost of paper lunch boxes. First, the prices of the raw materials used for pulp and individual chemical additives are high. Second, the energy consumed in the production process is high. Here, I just want to talk about how to reduce the energy consumption of paper lunch boxes. First, in the pulp adsorption molding part At present, the paper meal box adsorption molding, are used to suck the pulp with a vacuum pump to remove the moisture in the pulp slurry so that the pulp is attached to the forming network to complete. The vacuum pumps used by various manufacturers are mostly water ring vacuum pumps. This vacuum pump has a long history and is widely used in various industries such as chemical industry, light industry, Tongshun, and food. At present, various models, different specifications of water ring vacuum pumps are still applied in all walks of life. The biggest drawback of the water ring vacuum pump is high power consumption.
Roots vacuum pumps began to be promoted in China in the early 1970s. It is a new type of vacuum pump. The pump body has two long metal gears shaped like twist. Driven by a motor, the pair of gears move in opposite directions, thereby generating a suction effect on the gas or gas-water mixture, so that the material can be dehydrated and a vacuum can be formed. The biggest advantage of the Roots vacuum pump is that it saves electricity. Take the ZBK-4 water ring vacuum pump with a pumping rate of 10 cubic meters per minute. The motor used is a 30 kW pump that can be used with a Roots vacuum pump with the same pumping rate. The motor is only 15 kilowatts, which is half of the water ring vacuum pump, and its power saving effect is extremely obvious. As early as the 1970s, China has promoted the use of paper and other industries, which has played an important role in reducing the cost of products.
The water ring vacuum pump motor and pump body are connected by a coupling. In general, the speed of the vacuum pump is constant. The Roots type vacuum pump motor and the pump body are connected by a V-belt. By changing the diameter of the pulley, the rotational speed of the vacuum pump impeller can also be adjusted, so that the potential of the vacuum pump can be further exerted.
In the production process, no matter what kind of vacuum pump is used, if a gas-water separation tank can be installed in front of the suction inlet of the pump to separate the gas-water mixture entering the tank, so that the vacuum pump only draws in the gas, then the vacuum pump The power consumed can also be reduced by 5-10%. However, the drain pipe of this separator needs to have a sufficient depth so that moisture can be smoothly discharged into the trench under vacuum conditions. If the depth is not enough, the water will be drawn into the vacuum pump and the power saving effect will not be achieved.
The installation of the vacuum pump should be as close as possible to the suctioned part, and the connected piping should not be too thin. These measures are all designed to minimize the loss of necrosis in the pipeline to increase the efficiency of the vacuum pump. Second, in the wet food box press, dry dehydration part of the entire paper meal box production line, the most power consumption, energy-saving fur is the largest heat drying part. Here are two things to do. The sequence of extrusion and electrothermal drying are separated, first cold extrusion, take off some of the water, and then heated again, taking off another part of the water.
According to the data, removing the same amount of water from the wet pulp, such as removing a certain amount of water by steam heating, costs seven times the cost of removing the same weight of water by mechanical pressing. The use of electricity to heat the carrier to remove the same weight of water is more than ten times higher than the cost of cold crowding. Such large energy consumption had to be taken seriously by every paper lunch box manufacturer, and energy-saving measures were taken in every possible way to further reduce the cost of lunch boxes. In general, the excess water in the lunch box should be squeezed out as much as possible before the lunch box is dried. This part of the squeezed water can be discharged into the trench at room temperature or recycled. In other words, do not allow this part of the drained water to absorb excess heat and cause unnecessary energy consumption. It should be noted that extrusion dehydration can only remove a portion of the water in the wet lunch box, and cannot remove all the water. All we have to do is to squeeze out as much of the water as possible without destroying the shape of the lunch box, and then use heat to remove the rest of the water. At present, there are a number of lunch box manufacturers who, after molding the wet lunch box, immediately switch to the hot extrusion drying process, and both operate in the same way. In this way, it is possible to make the water that has been squeezed out heated and even heated. It is vaporized. As a result of this, a lot of valuable electricity is wasted. The heat source of the dry part is changed from electricity to steam. Electricity is a secondary energy source and is generally converted from steam. Every time you make an energy conversion, you lose some of your energy. The traditional papermaking machinery has always used steam as its final drying form. One of the important reasons is its economic efficiency and the feasibility of continuous production. At present, the vast majority of lunch box production lines use electric heating. As people's understanding of the production process continues to improve, it is believed that manufacturers will certainly develop new production processes and equipment that will replace electric drying paper fast food boxes in the future.
In short, reducing the cost of paper molded snack boxes has been a major problem for all fast food box manufacturers. In this article we introduce several ways to reduce energy consumption. All enterprises must make a fuss in this respect, and they must also rely on the characteristics of their own production lines and adapt them to local conditions. Only in this way can we do a good job of reducing costs. (Author: Beijing Baxter Machinery Manufacturing Company Qiu Gangyi)
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