With the rapid development of modern cold chain logistics, refrigerated trucks are more and more widely used, from dairy products, meat products, catering, medicine and other industries, have been associated with refrigeration. Its purpose is to ensure the quality of the product is stable. However, there are still phenomena such as product damage during use, and the reason for rectification is mainly caused by the incorrect use of the refrigerated truck. So how should we use refrigerated trucks? How to avoid the risks caused by improper use? The following will introduce to you.
1. Correct operation ensures that the goods are stored and shipped in perfect condition.
Only the correct use and operation of refrigerated trucks can ensure the good delivery and preservation of goods. Because refrigerated trucks are specially used for temperature-sensitive products, temperature assurance is the key to refrigerated trucks. If used or handled improperly, the goods will not be stored or shipped in perfect condition.
2. Preventive maintenance minimizes maintenance and operating costs.
In our normal use process, the maintenance and maintenance of the vehicle and the refrigerator are inseparable. Only correct maintenance and maintenance of the equipment on time can ensure the normal use of the equipment and prolong the service life of the equipment. Usually the chassis engine is maintained and maintained according to the mileage, while the refrigeration unit is maintained and maintained according to the engine operating hours. Usually the refrigeration unit is maintained and maintained every 500~700 hours, and the oil filter element, fuel filter element and air filter element need to be replaced; and pay attention to check the tightness of the belt and whether there is any leakage in the refrigeration system; however, at present, individual brands of refrigeration units (such as In order to meet the needs of environmental protection, minimize the damage to the environment and reduce the emission of harmful substances, synthetic oil or semi-synthetic oil is used to replace ordinary oil, thereby extending the maintenance time of the engine, usually done once every 2000 hours maintainance. Therefore, the discharge of waste oil is reduced. In addition, scientific experiments have proved that by using this high-end oil, not only the wear and tear of the engine can be reduced, but also the fuel consumption of the engine can be reduced. Therefore, scientific maintenance and maintenance can not only ensure the integrity of the equipment, but also reduce operating costs.
3. Proper packaging is essential to protect your cargo.
Use non-ventilated packing boxes for frozen goods, and use side-wall ventilated packing boxes for fresh goods. The packing box must be pressure resistant.
Since the frozen goods are not allowed to have wind blowing from the surface, because the wind blowing over the surface of the frozen goods will cause the loss of moisture in the goods, resulting in the deterioration of the quality of the goods. This year, our country has formulated that bulk quick-frozen foods are not allowed to be sold. This is the reason why they must be packaged for sales. However, due to its own characteristics, fresh products are still in a breathing state during storage and transportation. If they cannot be well ventilated, the goods will be deteriorated and damaged. Therefore, it is necessary to ensure that such goods have good ventilation and ventilation.
4. Set the thermostat to the desired temperature
Pre-cool the car for 1.5 hours to remove the heat trapped in the car; turn off the refrigeration unit when loading, and load quickly.
When loading, the carriage must be pre-cooled or pre-heated. Because the vehicle is parked in the open air, the cabin temperature is usually the outside ambient temperature. If the temperature of the delivered goods is not the ambient temperature, and the goods are loaded into the compartment, the ambient temperature will affect the temperature of the delivered goods, resulting in changes in the quality of the delivered goods. Therefore, the carriage must be pre-cooled to the required temperature before loading. However, the refrigeration unit must be switched off during loading (same as unloading). Many people do not turn off the refrigeration unit when loading and unloading goods. In fact, this is a very wrong operation.
The reason is: when we pre-cool the car, if we do not shut down 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 flows from the upper part of the car. Blow out, and the lower part will quickly suck in the hot air from the outside, which will cause the temperature in the cabin to rise rapidly; if the cargo is loaded and unloaded after the machine is turned off, because the fan is in a stopped state, the air flow stops, and the wind pressure inside and outside the cabin is the same, which makes the external heat. The speed of air transfer into the cabin is relatively slow.
5. The cargo must be pre-cooled to the required temperature, and the cargo temperature should be checked during loading; the refrigeration unit is used to maintain the temperature of the cargo, not to reduce the temperature of the cargo.
Many users of refrigerated trucks have a misconception that the refrigeration unit on the refrigerated truck can freely freeze or heat the cargo loaded into the compartment to the temperature it needs. Therefore, the cargo that is not enough to be transported is loaded into the compartment, and then the refrigeration unit is set to the required transport temperature, and the temperature of the cargo is lowered or raised to the required temperature within a certain period of time. However, the fact is the opposite. Not only does the temperature of the goods fail to fall (or rise), but the goods are damaged or deteriorated. Because the refrigeration unit of the refrigerated truck does not lower the temperature of the cargo, but maintains the temperature of the cargo, it wraps the cargo like the quilt we used to sell cold drinks in the past. When the external cold (heat) source enters the car through radiation, conduction and convection, it is taken away by the cold air blown by the refrigeration unit, and the heat source is isolated from entering the cargo.
Therefore, when loading the goods, the temperature of the loaded goods must be measured first. 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 cabin 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, which will shorten the shelf life of the goods.
6. Even if the unit capacity exceeds what is actually needed, insufficient air circulation can be a major cause of item spoilage; any blockage around the cargo can cause - "hot spots".
A qualified refrigerated truck must ensure that the six sides of the compartment have good ventilation, and there is no obstruction on the six sides of the goods; good air circulation can ensure that the goods are transported under the appropriate temperature requirements. The cold (hot) gas blown by the refrigeration unit isolates the cold (hot) source entering the compartment from the outside world from the cargo, thereby protecting the cargo. If a blockage occurs at a certain location, the cold (hot) source of that part will directly enter the item, causing the temperature of the item to change. Make sure the return air shutters are in good condition; do not block the inlet to the evaporator (return air); insufficient return air will create irregular circulation of cold air and cause top cargo to freeze.
7. The goods must be stacked on double-sided pallets; the pallets of fresh-keeping goods cannot be covered with plastic film, which will block the circulation of circulating cold air to the goods; the floor under the goods cannot be blocked.
The general refrigerated truck floor is a ventilated aluminum rail floor; however, some refrigerated trucks do not have aluminum rails and use a flat non-slip floor. Usually used as a third-party transportation company or enterprise transportation vehicle for dairy products, a flat non-slip floor is used, which is suitable for the transportation of various products, or to facilitate the cleaning of the floor. However, when loading, you must pay attention, and you must 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.
8. Do not stack cargo in front of the evaporator outlet, otherwise it will block the cold air flow; blockages above the cargo can cause a short circuit of the cold air flow. Maintain a minimum distance of 225mm between the top of the cargo and the roof.
When loading, do not stack the goods too high, and 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 goods or is 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 cargo, the cold air (or hot air) cannot be circulated normally in the cabin, thus increasing the local temperature of the cargo.
On the other hand, due to the defrosting design of refrigeration units, some use air induction defrosting. When the cargo is too close to the air outlet, the coil in the evaporator of the unit will quickly freeze (or ice), the air sensor switch will act immediately, and the unit will quickly enter the defrosting state; when the coil temperature rises to 9 degrees (design temperature) left or right, the defrost ends immediately. As a result, the above-mentioned operation of the unit will occur cyclically, resulting in the phenomenon that the temperature in the car cannot be lowered. The only impression to everyone is that the unit always defrosts frequently. In fact, it is due to the fact that the goods are loaded too high (too much).
9. The interior of the cabin must be kept clean; there should be no wrapping paper and paper scraps left on the floor; debris can block air flow or be sucked in by the evaporator.
When using a refrigerated truck, the floor of the compartment should be kept clean. Due to the effect of the evaporator fan, air circulates in the cabin, causing chips or dirt on the ground to be sucked in by the evaporator fan. For a long time, a large amount of impurities will be sucked into the evaporator coil, which will affect the cooling effect of the refrigeration unit. Because the coil will be surrounded by impurities little by little, the heat exchange rate of the coil will decrease. Therefore, after a few years of use of the refrigerated truck, everyone will feel that the cooling effect is not as good as the beginning. In addition to the cause of the failure itself, it is because the coil is too dirty. Therefore, ensuring the cleanliness of the ground in the compartment is the key to ensuring the normal operation of the refrigeration unit.
10. Proper handling; freezers should be turned off when doors are open; door opening times should be kept as short as possible; strip curtains should be used whenever possible when loading and unloading. Use dividers to separate dry goods (empty baskets) from perishables.
In order to ensure the temperature of the cargo in the compartment, it is recommended to use a strip door curtain for the delivery vehicles in the city to ensure that the air-conditioning in the compartment will not be quickly dissipated when the cargo is unloaded 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. Since the freezer is used to maintain the temperature of the goods, not to cool them down, the mixing 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 trucks is the key to ensuring the quality of temperature-controlled goods. It is also the place to ensure that the refrigeration equipment can work normally.
What you must know about using a refrigerated truck
1). Refrigerated truck ¡Ù cold storage, the main function of refrigerated truck is to maintain the temperature of goods
Many customers think that the refrigeration unit on the refrigerated truck can freeze or heat the cargo loaded in the compartment to the necessary temperature at will. This view is seriously wrong. In fact, the refrigeration unit is used to maintain the temperature of the cargo, not to reduce the temperature of the cargo. It is a bit similar to the quilts used to sell cold drinks in the past. The goods are wrapped. When the outside temperature enters the compartment of the refrigerated truck through radiation, conduction and convection, it will be taken away by the cold air blown by the refrigeration unit, isolating the heat source from entering the goods.
2). The loaded goods must meet the transportation temperature, otherwise they may deteriorate
Many customers think that if the goods with too high or too low temperature are loaded into the compartment of the refrigerated truck, the refrigeration unit is set to the necessary transportation temperature of the goods to be transported, and the temperature of the goods can be lowered or raised to the necessary temperature within a certain period of time. temperature. This view is also wrong. In fact, if the goods are transported in this way, the temperature of the goods will not be lowered (or not raised), but will be damaged or deteriorated. The cold air blown by the refrigeration unit will change the temperature of the goods, and the moisture of the goods will be lost, which will lead to changes in the quality of the goods, which will lead to the deterioration of the quality of the goods, the shortening of the storage period, and even the deterioration of the goods.
It is very likely that the carton of fresh beans you pull will be "drier" at the destination, and the weight will be reduced a lot, causing trouble. This is also the reason why refrigerated trucks generally go to cold storage to pull goods, and rarely go to the fields to directly pull goods.
3). When loading and unloading goods in refrigerated trucks, the refrigeration unit must be turned off
Many customers do not turn off the refrigeration unit when loading and unloading goods, thinking that this will make the temperature of the goods rise more slowly. In fact, this is a very wrong understanding.
If the refrigeration unit is not turned off, when the door of the compartment is opened, because the fan of the evaporator of the refrigeration unit is working, the fan blows the cold air out from the upper part of the compartment, and the lower part will quickly suck in the hot air from the outside, which will cause the temperature in the compartment to rise rapidly. ; If the cargo is loaded and unloaded after the machine is turned off, because the fan is in a stopped state, the air flow stops, the wind pressure inside and outside the cabin is the same, and the speed of the outside hot air entering is slower.