Views: 2005 Author: Site Editor Publish Time: 2019-04-25 Origin: Site
The output of China's agricultural products is huge, and the output of grain, meat, eggs, and aquatic products, fruits and vegetables has shown rapid growth. Therefore, ensuring food quality and reducing food loss is a systematic project and a livelihood project.Nowadays, some large and medium-sized cities use a refrigerated truck for transportation. As the industry penetration rate is still very low, there will still be a large amount of food, meat, fruits, vegetables, medicines, alcohol, etc., which will deteriorate during transportation every year. Unnecessary losses. Vigorously promoting and applying energy-saving and environmentally-friendly refrigerated trucks is of great significance for further integrating the refrigerated truck market, improving the status of China's refrigerated transport industry, reducing the waste of perishable goods in transit, and ensuring food safety. It should receive the attention of all sectors of society.
First, the structural characteristics and choice of refrigerated trucks
The refrigerated truck is a refrigerated special transport vehicle equipped with a refrigerating device and a polyurethane insulated box. It is commonly used to transport frozen food (frozen vehicles), dairy products (milk transport vehicles), vegetables and fruits (fresh freight transport vehicles), vaccine drugs (vaccine transport vehicles) and so on.
The refrigerated truck is composed of the walking part of the special automobile chassis, the truck body parts (glass fiber reinforced plastic, color steel plate, aluminum alloy, stainless steel, etc.), the thermal insulation layer part (generally polyurethane), the refrigeration unit part, and the temperature recorder. For vehicles with special requirements, such as meat hooks, you can add accessories such as meat hooks, aluminum alloy guide rails, ventilation slots.
Refrigerated truck body manufacturing technology, at present, most of the domestic refrigerated truck manufacturers use the "sandwich" plate bonding technology assembled by pieces. The inner and outer skins are made of composite materials such as glass steel plate, color steel plate and aluminum alloy. The inner plate material should be made of different materials depending on the goods to be transported. The more expensive inner material plate should be stainless steel plate. The middle interlayer is a heat insulating material, and mainly uses a polyurethane foam material. The four sides are bonded with the polyurethane foam material by high-strength glue to form a closed panel; there are also injection-injection foaming and integral skeleton injection foaming.
Different goods have different requirements for the truck. For example, a refrigerated truck that transports fresh meat needs to be custom-made on the truck; a refrigerated truck that delivers goods to a store requires a multi-warm refrigerated truck because of the small size and variety of goods; for goods with different temperature requirements and frequent loading and unloading, Then you need to open the door refrigerated truck.
The power source from the refrigeration unit can be divided into two types: independent and non-independent units. The independent unit has a separate power source. The difference is that the independent unit is completely powered by another unit to maintain the work; the non-independent unit is completely driven by the engine's working power to drive the unit's cooling work.
Refrigerated truck refrigeration units are generally installed at the top of the front of the container, with an air-conditioned shape, but with a greater cooling capacity than the same volume of air conditioning. The average model uses an external chiller, and a few micro-refrigerators use a built-in chiller. For refrigerated trucks with lower temperature requirements, the built-in cold plate of the car can be used. Generally, the refrigeration unit with different power cooling capacity is selected according to the volume of the refrigerated truck body and the temperature requirement of the transported goods.
Second, the use of refrigerated trucks.
Refrigerated vehicles are specially used for the transportation and preservation of temperature-sensitive products. The protection of temperature is the key to refrigerated trucks. If used or mishandled, it will result in the goods being stored or shipped in a state of incomplete condition. Now I will introduce how to use the refrigerated truck correctly to avoid the risks caused by improper use.
Before loading, the truck must be pre-cooled or preheated for about 1.5h. Because the vehicle is parked in the open air, usually the temperature of the cabin is the temperature of the external environment. After the cargo is loaded into the compartment, the ambient temperature in the compartment will affect the temperature of the transported cargo, which will result in a change in the quality of the transported cargo. Therefore, the carriage must be pre-loaded before loading. Cool to the necessary temperature.
The refrigeration unit must be shut down during loading and unloading. Many people do not turn off the refrigeration unit when loading or unloading the goods. This is a very wrong operation. The principle is: when the truck is pre-cooled, if it is not turned off, when the truck door is opened, the fan of the evaporator of the refrigeration unit is working. The front of the fan is positive pressure, the back is negative pressure, so the cold air is blown out from the upper part of the compartment, and the lower part will quickly suck in the hot air outside, which will cause the temperature inside the compartment to rise rapidly; if the cargo is loaded and unloaded after shutdown, the fan is at In the stopped state, the air flow stops, and the wind pressure inside and outside the cabin is uniform, so that the speed at which the external hot air is transferred into the cabin is relatively slow.
When using a refrigerated truck, the floor of the carriage should be kept clean. Due to the action of the evaporator fan, air circulates in the cabin, causing debris or dirt on the ground to be drawn in by the evaporator fan. The long-term effect will cause a large amount of impurities to be sucked into the evaporator coil, thereby affecting the refrigeration performance of the refrigeration unit.
Proper packaging is essential to protect the goods. For frozen goods, non-ventilated boxes should be used. Because the wind blows over the surface of the frozen cargo, the moisture in the cargo is lost, resulting in a decline in the quality of the cargo. China's development of bulk frozen foods are not allowed to sell, there must be packaging sales is the reason; for fresh goods, the use of side wall ventilation box. Due to its own characteristics, fresh foods are still in a state of respiration during storage and transportation. If they are not well ventilated, the goods will deteriorate.
When loading, do not stack the goods too high, make sure that the loading height is not higher than the plane height of the air outlet. If the front of the air outlet is blocked by the cargo or too close to the cargo, it will not only affect the storage and transportation temperature of the cargo, but also affect the normal operation of the refrigeration unit. Because the air outlet is blocked by the cargo, the cold air cannot be normally circulated in the compartment, which will cause the local temperature of the cargo to rise. On the other hand, some of the defrosting design of the refrigeration unit uses air-induced defrosting to block the air outlet, which will greatly reduce the defrosting effect.
When loading, be sure to use double-sided pallets to load the goods to ensure the circulation of cold air on the ground. It is strictly forbidden to stack the goods directly on the flat floor; the plastic pallet can not be covered with plastic film, and the plastic film will block the circulating cold airflow to the cargo.
Third, the correct maintenance and overhaul of the refrigerated truck.
The maintenance of the refrigerated truck is essential. Only proper maintenance of the equipment on time can ensure the normal use of the equipment and extend the service life of the equipment.
Usually, the refrigeration unit performs maintenance every 500h~700h, and needs to replace the oil filter element, fuel filter element and air filter element; and pay attention to check the tightness of the belt and the leakage of the refrigeration system.
At present, some brands of refrigeration units in order to adapt to environmental protection needs, to minimize damage to the environment, reduce the emission of harmful substances, so the use of synthetic engine oil or semi-synthetic engine oil instead of ordinary engine oil, thus extending the maintenance time of the engine, usually in accordance with 2000h One maintenance. This reduces the emissions of used motor oil.
In addition, scientific experiments have shown that by using this high-end engine oil, not only the wear on the engine is reduced, but also the fuel consumption of the engine can be reduced. Therefore, scientific maintenance can not only ensure the integrity of the equipment, but also reduce operating costs.
In general, the daily maintenance of the truck body of the refrigerated truck is mainly reflected in the inspection of the outer surface of the car, the inspection of the inner surface of the truck, the inspection of the inner and outer corners of the truck, the inspection of the inner floor of the truck body, and the internal lighting and cooling air outlet. Check and so on.
Do not scrape the outer surface of the refrigerated compartment. Otherwise, the ability of the FRP to withstand the pressure will be reduced, and the aging deformation will be more likely to occur. On the other hand, the internal filled polyurethane will leak and affect the insulation performance of the truck.
The maintenance of the inner surface of the refrigerated truck should be adjusted to the temperature control. Do not let the surface of the car body freeze. If the air humidity is relatively large, it is necessary to pack the refrigerated products as much as possible. In particular, the seal of the aquatic product can be sealed to reduce the moisture to the interior of the truck. Evaporation reduces the possibility of icing inside the refrigerated truck. If there is a layer of ice on the inner surface of the refrigerated truck, it should be removed with a de-icing shovel every time after transporting the goods to prevent the ice layer from getting thicker and thicker. Otherwise, it will not only affect the storage space of the truck, but also increase the weight of the truck. Increase fuel consumption. Also, care should be taken to avoid damage to the inner surface of sharp goods or crates.
The refrigerated truck is recommended to perform the following maintenance before loading the cargo: the refrigerated truck fuel supply must be sufficient to ensure that the engine runs at least to the next service point; the refrigerated truck engine oil level should be at the (full) mark, do not overfill; see the amount of coolant is it right or not.
The battery terminal of the refrigerated truck must be secure and free from corrosion. The electrolyte should be at the full mark; the belt must be well adjusted to the proper degree of expansion, and the sag of the span between the pulleys is 13 mm; ensure that the electrical joints in the electrical control circuit are firmly fixed; the wires and terminals should be free of corrosion and burn. Damage cracking or moisture; visually inspect the unit for leaks, loose or broken parts, and whether the gasket of the gasket unit is tight; the refrigerated coil condenser and evaporator coil should be clean and free of dirt; The defrost drain is unblocked.
Fourth, the conclusion
In summary, refrigerated trucks play an important role in satisfying people's insulation and refrigerated transportation of food. With the improvement of people's living standards and the emphasis on food safety, the development of the cold chain industry is optimistic, and the market for refrigerated trucks is huge. It is imperative to strengthen the technical application of refrigerated trucks.