Views:94 Author:Site Editor Publish Time: 2021-04-28 Origin:Site
In recent years, the construction of cold chain logistics has become a hot spot in the logistics industry. Cold storage is a more important link in the entire cold chain. The one-time construction investment of the cold storage is large. It is necessary to ensure that the internal temperature of the cold storage reaches the required state, especially when the internal temperature of the cold storage is reduced to a stable constant temperature state required by the operating state in the initial stage of the cold storage operation, a large amount of electric power and other resources will be consumed.
Once the cold storage is in operation, the compressor equipment cannot stop the power supply at will, otherwise, it will affect the life of the overall building and the quality and safety of the stored goods. Therefore, the utilization of storage space in the warehouse and the turnover rate of warehoused goods are the most concerned issues of all cold storage owners. The level of its comprehensive indicators determines the length of the investment return period.
Application cases of drive-in racks
Nanjing Weixun Logistics Co., Ltd. (hereinafter referred to as Weixun) through discussions with a Beijing food company, based on its existing logistics needs, chose drive-in racks as the storage system for the new phase of the frozen warehouse. The warehouse is 59 meters long, 41 meters wide, and has a usable area of 2419 square meters. The indoor operating temperature is -18°C. The one-time input racks can be fully loaded with 3640 pallet positions. The layout of the warehouse is shown in Figure 1.
In order to ensure the convective circulation speed of the cold air of the fan inside the warehouse, part of the shelves designed by Jiuwei shelf adopts an unobstructed method (see Figure 2).
When designing drive-in racks, there are two key considerations:
1. How does the forklift enter the column to retrieve and retrieve the goods?
There are two situations:
① Drive in from the middle of the corbel: In this case, the fork direction of the pallet is more than 1.4 meters, and the requirements for forklift operators are not very high. The main point is to pay attention to the amount of deflection and deformation of the middle pallet panel after the pallet is placed on the shelf. The actual operation is shown in Figure 3.
② Drive into the column from below the corbel: In this case, the height of the corbel of the first layer is 2.3 meters, the height of the overhead guard of ordinary counterbalanced forklifts, and reach forklifts is less than 2.2 meters, and the pallet fork length is 1.2 meters. In this condition, the operation level of forklift workers is required to be relatively high. In order to prevent the forklift from hitting the pillars in the roadway, customers consider adding bottom guard rails when necessary.
The actual working situation is shown in Figure 4.
2. How many meters is the distance between the pallet and the limit position of the shelf?
Because the loading and unloading of goods on the drive-in racks mostly uses the "lifting high" method, when the forklift driver places the goods at a high place, his eyes cannot observe the design and theoretical position of the pallet goods on the top. The trays mostly slide along the shelf by friction, which is very likely to make the tray go far left or right. Therefore, the distance between two corbels and two adjacent pillars will be determined by this extreme value of the tray. So as to calculate the length of the top beam and the middle beam. The practice has proved that this extreme value is greater than or equal to 40 mm, and the tray is safe. When the tray is ideally centered, the distance from the limit edge of the shelf is ≥15mm. Moreover, also consider the width of the fork frame (see Figure 5).
Drive-in racking system cannot install beams in the access lanes, so sufficient attention must be paid attention to the strength, rigidity, and stability of the racks at the beginning of the design. Due to the material problem of the shelf materials, the drive-in shelf collapsed accidents have occurred many times in China. Therefore, the height of the drive-in rack should not be too high, and it is generally controlled within 10 meters, and the number of layers is within 4 layers.
For non-through shelves, back pulls and back beams should be added to increase the stability of the overall frame. The length of the pallet fork is within 1.3 meters. Because drive-in racks are cheaper than other forms of high-density racks, they are often used in warehouses in the food, tobacco, medicine, and cold storage industries.