A refrigerated truck is a closed box transporter for transporting frozen or fresh cargo, a refrigerated transport unit equipped with a refrigeration unit and a refrigerated transport vehicle for polyurethane insulation. It is commonly used for transporting frozen foods (refrigerated vehicles) and dairy products. (milk transport vehicles), fruits and vegetables (fresh goods vehicles), vaccine drugs (vaccine transport vehicles), etc.
Structure: The refrigerated truck is composed of the walking part of the special-purpose automobile chassis, and the heat insulation and heat preservation body (usually composed of polyurethane material, glass fiber reinforced plastic, color steel plate, stainless steel, etc.), refrigeration unit, compartment temperature recorder and other components, for special requirements. Vehicles, such as meat hooks, can be fitted with meat hooks, waistbands, aluminum alloy rails, ventilation slots and other optional accessories.
Refrigerated car body production technology:
1. The “sandwich†plate bonding type of split sheets is assembled. At present, larger refrigerated truck manufacturers in China have adopted this technology. Refrigerator vehicles produced using this technology have higher heat insulation performance.
2. Fragmented injection foam type.
3, the overall skeleton injection foam type.
4. Vacuum Adsorption Pasting According to chassis load capacity classification: Micro-refrigerated cars, small-sized refrigerated trucks, medium-sized refrigerated trucks, and large-scale refrigerated trucks are classified by car type: bread-type refrigerated trucks, van-type refrigerated trucks, and semi-trailer refrigerated trucks There are many, the following five are more common cooling methods
1 Water Ice and Salt Ice Refrigeration At atmospheric pressure, the melting point of ice is 0°C. The endotherm of melting ice is 334.8kJ/kg. Adding salt in water ice can reduce its melting point. Within a certain range, the more salt in water ice, the lower the melting point. Experiments have shown that when the mass of salt added is 29% of the mass of water ice, the melting point of the mixture can reach a minimum value of -21.2°C. If you add more salt, the melting point no longer declines. The salt ice of different compositions is usually selected based on the proper temperature of the refrigerated cargo. For example, using salt ice with a salt content of 22%, the temperature in the compartment can be maintained at -18~-13°C.
The water ice refrigeration device has a low investment and a low operating cost, but ordinary water (salt) ice has a small amount of heat absorption per unit mass, and the cooling in the vehicle compartment is limited. In addition, melting of salt ice will pollute the environment and food, corrode the car and the value of goods damp. Therefore, water (salt) ice cooling is mainly used for refrigerated transport of fish and other aquatic products.
2 Dry ice refrigeration Under an atmospheric pressure, the sublimation temperature of dry ice (solid CO2) is low (-78.9°C), and the sublimation heat absorption is large (573.5kJ/kg), so it is used as a cold source of the compartment and not only can obtain lower temperature (Generally less than -20°C), and a larger amount of cooling can be obtained. Therefore, this refrigeration method is suitable for the transportation of frozen foods.
Dry ice refrigeration unit is simple, low investment and operating costs, easy to use, the goods will not be damp. The COZ gas produced by the sublimation of dry ice can inhibit the reproduction of microorganisms, slow the oxidation of fat, and weaken the respiration of fruits and vegetables. However, dry ice sublimation can easily cause frost formation. Excessive CO2 gas will lead to difficulty in breathing of fruits and vegetables and colds. The temperature in the cabin is difficult to adjust. Dry ice is expensive and consumes a large amount, so it is less practical.
3 Cold plate cooling The principle of cold plate cooling is to use the amount of cold stored in the cooling agent for refrigeration. Before the transportation, the cold storage agent in the cold plate in the compartment is “cooled†to cool it, and then the cold storage agent in the cold plate is used to melt and absorb the heat during the transportation, so that the temperature in the compartment is maintained in the proper temperature range of the transported cargo. Inside. Therefore, the cold plate is also called "storage plate."
The structure of the cold plate cooling device is divided into integral type and split type. Integrated power units, refrigeration units, cold storage panels, etc., are all placed on the dry truck; split-type vehicles are equipped with only refrigeration units and cold storage panels. When parking, the solid-state power unit drives the refrigeration unit to “cool†the cold storage plate. The latter is often used in practical applications. Commonly used coolants are low melting point eutectic solutions, and their melting point is usually about 10°C lower than the appropriate temperature in the compartment. When the proper temperature of the goods to be transported changes, the composition of the selected eutectic solution must also change.
The cold plate device itself is heavier and has a larger volume and occupies a certain volume of the compartment, and the cold plate can only be cooled continuously for 8 to 15 hours at a time. Therefore, cold plate refrigeration is suitable for medium and short-distance transportation of medium and light refrigerated vehicles. In recent years, with the increasingly prominent problems of energy and environmental pollution, the application of cold plate cooling has developed rapidly and has become the second only to mechanical refrigeration. the way.
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