How to use refrigerated truck correctly？
Correct operation can ensure that the goods can be preserved and transported in good condition. Only the correct use and operation of refrigerated trucks can ensure the good transportation and preservation of goods. Because the refrigerator car is specially used for temperature sensitive products, so the temperature guarantee is the key to the refrigerator car. If used or operated improperly, the goods will not be preserved or transported in good condition.
（1）Maintenance and repair of refrigerated vehicles: preventive maintenance can minimize the maintenance and operating costs
In our normal use process, the maintenance of vehicles and refrigerators is inseparable. Only when the equipment is properly maintained on time can the normal use of the equipment be ensured and the service life of the equipment be prolonged.
Usually, the chassis engine is maintained according to the mileage, while the refrigeration unit is maintained according to the working hours of the engine. The usual refrigeration unit is 500 ~ 700 hours for a maintenance, need to replace the oil filter, fuel filter, air filter; and pay attention to check the belt tightness, refrigeration system leakage, etc.; however, the current individual brand of refrigeration unit (such as ThermoKing) in order to meet the needs of environmental protection, try to reduce the damage to the environment, reduce the emission of harmful substances, so as to reduce the pollution Synthetic oil or semi synthetic oil is used to replace ordinary oil, so as to prolong the maintenance time of the engine, which is usually maintained every 2000 hours. Therefore, the waste oil emission is reduced.
In addition, scientific experiments have proved that the use of this high-end oil can not only reduce the wear of the engine, but also reduce the fuel consumption of the engine. Therefore, scientific maintenance can not only ensure the integrity of equipment, but also reduce operating costs.
(2)Proper packaging is essential for the protection of the goods.
For frozen goods, non ventilated packing boxes are used, and for fresh goods, side wall ventilated packing boxes are used. The packing box must be pressure resistant. It is not allowed for wind to blow through the surface of frozen goods, because the wind will cause the loss of moisture in the goods, resulting in the decline of the quality of goods. This year China formulates about the bulk quick-frozen food all forbids the sale, must have the packing sale, is this truth. Because of its own characteristics, fresh goods are still in a breathing state in the process of storage and transportation. If not well ventilated, the goods will be deteriorated and damaged. Therefore, it is necessary to ensure that such goods have good ventilation.
(3)Temperature control of refrigerated compartment.
Precooling the truck for 1.5 hours to remove the heat remaining in the truck; closing the refrigeration unit during loading and loading quickly. When loading, the carriage must be pre-cooled or pre-heated. It's usually the outside temperature of the car. If the temperature of the transported goods is not the ambient temperature, when the goods are loaded into the carriage, the ambient temperature will affect the temperature of the transported goods, resulting in changes in the quality of the transported goods. Therefore, the carriage must be pre-cooled to the required temperature before loading. However, the refrigeration unit must be shut down during loading (as in unloading).
Many people do not turn off the refrigeration unit when loading and unloading goods. In fact, this is a very incorrect operation. And the reason for that is when we pre-cool the car, if we don't turn off the car and open the car door, because the fan of the evaporator of the refrigeration unit is working, the front of the fan is positive pressure, and the back of the fan is negative pressure, so the cold air will blow out from the upper part of the car, and the lower part will quickly draw in the hot air outside, resulting in the rapid rise of the temperature in the car; if we load and unload the goods after the car is turned off, Because the fan is in the stop state, the air flow stops, and the air pressure inside and outside the car is the same, so the speed of external hot air transfer into the car is relatively slow.
(4)Cargo pre-cooling or preheating: the cargo must be pre-cooled to the required temperature, and the cargo temperature shall be checked when loading.
The refrigeration unit is used to maintain the temperature of the goods, not to reduce the temperature of the goods.
Many users of refrigerated vehicles have a wrong concept: they thought that the refrigeration unit on the refrigerated vehicle can freeze or heat the goods in the compartment to the required temperature at will. Therefore, load the goods that are not up to the required transportation temperature into the compartment, set the refrigeration unit to the required transportation temperature, and reduce or increase the temperature of the goods to the required temperature within a certain period of time.
However, on the contrary, not only can the temperature of the goods not fall (or rise), but also the goods will be damaged or deteriorated. Because the refrigeration unit of the refrigerator car does not reduce the temperature of the goods, but maintains the temperature of the goods. It is like the quilt we used to sell cold drinks to wrap the goods. When the external cold (heat) source is radiated, conducted and convected into the compartment, it is taken away by the cold air blown out by the refrigeration unit to isolate the heat source and enter the goods.
Therefore, the temperature of the loaded goods must be measured before loading. If the set point temperature of the refrigeration unit is higher or lower than the cargo temperature, it is difficult for the cargo temperature in the compartment to reach the temperature required for transportation. The storage temperature of the goods must be consistent with the transportation temperature. If the temperature of the goods changes frequently, the moisture will be lost, which will lead to changes in the quality of the goods and shorten the shelf life of the goods.
(5)Do not stack goods in front of the evaporator outlet, otherwise it will hinder the cold air flow.
Obstruction above the cargo can cause a short circuit in the cold air flow. Maintain a minimum distance of 225 mm between the top of the load and the roof. When loading, don't pile the goods too high. Make sure the loading height is not higher than the plane height of the air outlet. If the front of the air outlet is blocked or too close to the goods, it will not only affect the storage and transportation temperature of the goods, but also affect the normal operation of the refrigeration unit. Because the air outlet is blocked by the goods, the cold air (or hot air) can not circulate in the car normally, so the local temperature of the goods increases. On the other hand, due to the defrosting design of the refrigeration unit, some use air induction defrosting. When the goods are too close to the air outlet, the coil in the evaporator of the unit will quickly frost (or ice), the air induction switch will act immediately, and the unit will quickly enter the defrosting state; when the coil temperature rises to about 9 degrees (design temperature), the defrosting will immediately end. Therefore, the above operation will be repeated in the unit, resulting in the phenomenon that the temperature in the box can not drop down. The intuitive feeling is that the unit always defrosts frequently. In fact, it is because the goods are loaded too much.
The refrigerator should be closed when the door is opened; the opening time of the door should be shortened as far as possible; the strip curtain should be used when loading and unloading goods. Use partitions to separate dry goods (empty baskets) from perishable goods. In order to ensure the temperature of the goods in the compartment, it is recommended to use the strip curtain for the distribution vehicles in the city, so as to ensure that the air-conditioning in the compartment will not be lost quickly when the refrigeration unit is not turned off. Goods with different temperatures are strictly prohibited to be stored in the same compartment. They should be separated by partitions. Because the refrigerator is used to maintain the temperature of the goods, not to cool them down, the mixed loading of goods with different temperatures will affect the temperature of the goods and affect the quality of the goods. Correct operation and use of refrigerated truck is the key to ensure the quality of temperature controlled goods. It is also the place to ensure the normal operation of refrigeration equipment. The container of the heat insulation refrigerator car is similar to the container, but it is made of the material with better heat insulation effect, which reduces the heat exchange.
Because the food cold chain is a supply chain system which aims at ensuring the quality of perishable food and keeping the low temperature environment as the core requirement, it has higher and more complex requirements than the normal temperature logistics system, and the construction investment is also much larger, which is a huge system engineering.