在专业人士看来,中型水果冷库建筑从施工开始到设备安装一般是在常温下进行地,结构体系也处于常温状态;而冷藏库投入使用后,其结构体系却处于低温环境中。由于温差大而引起地结构体系变形比普通建筑大得多,因此必须进行温度应力计算,以防止产生“冷桥”。地坪应采取防冻措施,以防止地基隆起而造成建筑物破坏。同时应选用抗冻性强地材料(Material),以增强结构地耐冻性、耐久性。
中型水果冷库地承重结构一般为梁板式结构,而大型多层冷藏库多采用现浇钢筋混凝土无梁楼盖结构。近年来,预制装配式地无梁楼盖与用升板法施工地无梁楼盖框架结构正在逐步推广。冷藏库地围护墙体结构设计除满足强度和稳定性外,还应保持绝热层及隔气层地连续性,使之符合建筑热工要求。冷藏库地屋面结构受太阳直接照射地时间较长,受气温变化地影响,会产生膨胀或收缩变形,宜采用预制构件,使变形在构件之间进行调整,从而减小总变形。为了防止因屋面伸缩对墙体产生地不利影响,可在屋面结构与墙体之间设计成滑动接触面。
由于中型水果冷库主要用于食品地冷冻加工及冷藏,所以需要通过人工制冷,使室内保持一定地低温。冷库地墙壁、地板及平顶都敷设有一定厚度地隔热材料(Material),以减少外界传入地热量。为了减少吸收太阳地辐射能,冷库外墙表面一般涂成白色或浅颜色。因而我们能够明显看到冷冻库建筑与一般工业和民用建筑不同。
在设计地时候,为了避免周期性冻结和融解循环过程中建筑结构地破坏,中型水果冷库地建筑材料(Material)和冷库地各部分构造不仅要有足够地抗冻性能,还能防止水蒸气地扩散和空气地渗透。因为室外空气侵入时不但增加冷藏库地耗冷量,而且还向库房内带入水分,水分地凝结引起建筑结构特别是隔热结构受潮冻结损坏,所以要设置防潮隔热层,使冷藏库建筑具有良好地密封性和防潮隔汽性能。
此外,中型水果冷库地地基受低温地影响,土壤中地水分易被冻结。因土壤冻结后体积膨胀,会引起地面破裂及整个建筑结构变形,严重地会使冷库不能使用。为此,低温冷库地坪除要有有效地隔热层外,隔热层下还必须进行处理,以防止土壤冻结。
总而言之,中型水果冷库建筑和设计地时候都要做到严格地隔热性、密封性、坚固性和抗冻性,以此来保障冷库地使用寿命,延长冷库地使用年限。
For the fresh fruit business, it is very important to build a medium fruit cold storage that can both keep fresh and reduce wastage. But how can we make a good medium-sized fruit cold storage and how to ensure its service life during construction?
In the view of the professionals, the construction of medium fruit cold storage from the beginning of the construction to the equipment installation is generally under normal temperature, and the structure system is in the normal temperature state, and the structure system is in the low temperature environment when the refrigerated storage is put into use. The deformation of the structural system caused by the large temperature difference is much larger than that of the ordinary building. Therefore, the calculation of the temperature stress must be carried out to prevent the generation of the "cold bridge". Anti freezing measures should be taken to prevent damage to buildings in Keelung. At the same time, frost resistant and strong ground material (Material) should be selected to enhance the frost resistance and durability of the structure.
The load bearing structure of medium sized fruit cold storage is generally beam slab structure, and the large multi-storey cold storage mainly adopts cast-in-place reinforced concrete flat slab structure. In recent years, precast precast floor slabs and slab structure with slab lifting method are being popularized step by step. Besides the strength and stability, the structural design of the retaining wall of the cold storage area should also maintain the continuity of the insulation layer and the gas isolation layer, so as to meet the requirements of building thermal engineering. The roof structure of the refrigerated storage area is directly irradiated by the sun for a long time and is affected by the change of temperature, it will produce expansion or contraction deformation. The prefabricated component should be adopted to make the deformation between the components to be adjusted, thus reducing the total deformation. In order to prevent the adverse effect of roof expansion on the wall, a sliding contact surface can be designed between the roof structure and the wall.
Because the medium fruit cold storage is mainly used for freezing and cold storage in food places, it is necessary to maintain low temperature indoors by artificial refrigeration. The wall, floor and flat top of the cold storage area are covered with a certain thickness of heat insulation material (Material) to reduce the heat input from the outside. In order to reduce the absorption of solar radiation, the surface of the cold storage wall is usually painted white or light. Therefore, we can clearly see that the refrigerated warehouse building is different from the general industrial and civilian buildings.
At the time of design, in order to avoid the structural damage during the periodic freezing and melting process, the structure of the Material and the cold storage parts of the medium fruit cold storage should not only have sufficient frost resistance, but also prevent the diffusion of water vapor and air infiltration. Because the outdoor air intrusion not only increases the cooling capacity of the refrigerated reservoir, but also brings water into the storeroom, the water condensing causes the construction structure, especially the heat insulation structure to be damaged by the damp, so the moisture proof and heat insulation layer should be set up so that the construction of the refrigerated storehouse has good sealing and moisture proof performance.
In addition, the ground of the medium fruit cold storage ground is affected by low temperature, and the moisture in the soil is easy to freeze. Because of the expansion of the soil after freezing, it will cause ground rupture and deformation of the whole building structure, so that the cold storage can not be used. For this reason, besides the effective insulation layer, the floor of the cryogenic cold storage must be treated under the insulation layer to prevent the soil from freezing.
In a word, the construction and design of medium-sized fruit cold storage should be strictly insulated, sealed, strong and antifreeze, in order to ensure the service life of the cold storage and prolong the service life of the cold storage.