1. Preventive maintenance refrigerated trucks can minimize maintenance and operating costs.
In our normal use process, the maintenance and maintenance of refrigerated vehicles and refrigerators are inseparable. Only when the equipment is properly maintained and maintained on time can the normal use of the equipment and the life of the equipment be extended. Chassis engines are generally maintained and maintained according to mileage, while refrigeration units are maintained and maintained according to engine operating hours. Generally, the refrigeration unit performs maintenance and repair once every 500-700 hours, and the oil filter element, fuel filter element, and air filter element need to be replaced; pay attention to check the tightness of the belt and whether the refrigeration system leaks.
However, in order to meet the needs of environmental protection, the refrigeration units of some brands (such as the Cold King of the United States) currently minimize the damage to the environment and reduce the emission of harmful substances. Therefore, synthetic or semi-synthetic motor oil is used instead of ordinary motor oil, thereby extending the engine Maintenance time, usually every 2000 hours. As a result, emissions of used motor oil are reduced. In addition, scientific experiments have proven 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 and maintenance can not only ensure the integrity of the equipment, but also reduce operating costs.
2. Proper packaging is essential to protect the goods.
Unventilated packaging boxes for frozen goods, and sideboard ventilation boxes for fresh goods. The box must be pressure resistant. Because frozen cargo is not allowed to blow through the surface, because the wind blows over the surface of the frozen cargo, it will cause the loss of moisture in the cargo, which will cause the quality of the cargo to decline. This year, our country has formulated that all quick-frozen foods in bulk are not allowed to be sold, and it must be packaged for this reason. Due to its own characteristics, fresh products are still in the breathing state during storage and transportation. If they cannot be well ventilated, the goods will be damaged. Therefore, it must be ensured that such goods are well ventilated and ventilated.
3. Set the thermostat to the required temperature, pre-cool the car box for 1.5 hours to remove the heat left in the car box; turn off the refrigeration unit when loading, and load quickly.
When loading, the cabin must be pre-cooled or pre-heated. Because the vehicle is parked in the open air, the temperature of the cabin is usually the ambient temperature. If the temperature of the cargo to be transported is not the ambient temperature, the cargo is loaded into the carriage, and the ambient temperature will affect the temperature of the transported cargo, resulting in changes in the quality of the transported cargo. Therefore, the compartment must be pre-cooled to the required temperature before loading. However, the refrigeration unit must be shut down during loading (same as unloading). Many people do not shut down the refrigeration unit when loading and unloading cargo, which is actually a very wrong operation.
The reason is: When we pre-cool the compartment, if we do not shut down and open the compartment door, because the fan of the refrigeration unit evaporator is working, the front side of the fan is positive pressure, and the back side is negative pressure, so the air-conditioning is from the upper part of the compartment. It blows out, and the lower part will quickly draw in the hot air from outside, which will cause the temperature inside the compartment to rise rapidly. If the cargo is loaded and unloaded after the shutdown, the air flow will stop because the fan is stopped, and the air pressure inside and outside the compartment will be the same. The speed at which air passes into the cabin is relatively slow.
4. The cargo must be pre-cooled to the required temperature, and the cargo temperature should be checked when 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 wrong concept. They always think that the refrigerating unit on refrigerated trucks can freely freeze or heat the goods loaded in the compartment to the temperature they need. Therefore, load the cargo that is less than the required transport temperature into the carriage, and then set the refrigeration unit to its required transport temperature, and reduce or raise the cargo temperature to its required temperature within a certain period of time. However, the opposite is true. Not only does the temperature fail to fall (or cannot rise), but the goods are damaged or deteriorated. Because the refrigerating unit of the refrigerated truck does not reduce the temperature of the cargo, but maintains the temperature of the cargo, he is like the quilt we used to sell cold drinks in the past to wrap the cargo. When the external cold (heat) source enters the compartment through radiation, conduction, and convection, it is taken away by the cold air blown out by the refrigeration unit to isolate the heat source from entering the cargo.
Therefore, when loading, the temperature of the loaded goods must be measured first. If the setpoint 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, moisture will be lost, which will cause changes in the quality of the goods, which will shorten the shelf life of the goods.
5. Even if the capacity of the unit exceeds the actual requirement, insufficient air circulation will be the main reason for the deterioration of the item; any blockage around the cargo may cause-"hot spots".
A qualified refrigerated truck must ensure good ventilation on the six sides of the carriage, and there is no obstruction on the six sides of the cargo; good air circulation can ensure that the cargo is transported at the right temperature. The cold (hot) gas from the refrigeration unit isolates the cold (hot) source from the outside into the compartment from the cargo, thereby protecting the cargo. If a blockage occurs at a location, the cold (hot) source of that portion directly enters the item, causing the cargo temperature to change. Make sure the return air shield is in good condition; do not block the inlet of the evaporator (return air); insufficient return air will cause irregular circulation of cold air and cause the top cargo to freeze.
6. The goods must be stacked on double-sided pallets; the fresh-cargo pallets must not be covered with a film, which will block the circulating cold air flow to the cargo; the floor under the cargo must not be blocked.
The general refrigerated truck floor uses ventilated aluminum rail flooring; however, some refrigerated trucks do not have aluminum rails and use flat non-slip floors. Usually used as a third-party transportation company or for dairy products, the company's transportation vehicle uses flat non-slip flooring, which is suitable for the transportation of multiple products, or to facilitate the cleaning of the floor. However, care must be taken during loading, and double-sided pallets must be used for loading to ensure the circulation of cold air on the ground. It is strictly prohibited to stack goods directly on a flat floor.
7. Do not stack cargo in front of the evaporator outlet, otherwise it will hinder the cold airflow; the blockage above the cargo will cause a short circuit of the cold airflow. Keep a minimum distance of 225 mm between the top of the cargo and the roof of the car.
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 cargo or is 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 (or hot air) cannot normally circulate in the compartment, thereby increasing the local temperature of the cargo. On the other hand, due to the defrost design of the refrigeration unit, some use air induction defrost.
When the cargo is too close to the air outlet, the coils in the unit's evaporator will quickly frost (or ice), the air sensor switch will immediately act, and the unit will quickly enter the defrost state; when the coil temperature rises to 9 degrees (design temperature) Right or left, the defrost ends immediately. As a result, the above-mentioned operation of the unit will occur in a reciprocating manner, resulting in a phenomenon that the temperature in the cabin cannot be reduced. The only feeling for everyone is that the unit always defrosts frequently. In fact, it is because the cargo is too high (more).
8. The interior of the carriage must be kept clean; there should be no wrapping paper and paper scraps on the floor; debris will hinder air flow or be sucked in by the evaporator.
When using refrigerated trucks, the floor of the cabin should be kept clean. Due to the effect of the evaporator fan, air will circulate inside the cabin, causing chipping or dirt on the floor to be sucked in by the evaporator fan. Prolonged action will cause a large amount of impurities to be sucked into the evaporator coil, thereby affecting the cooling effect of the refrigeration unit. Because the coil will be surrounded by the impurities a little, the heat exchange rate of the coil will decrease. Therefore, after using the refrigerated truck for several years, everyone will feel that the cooling effect is not as good as the beginning. Except for the failure reason itself, it is because the coil is too dirty. Therefore, ensuring the cleanliness of the ground in the carriage is the key to ensuring the normal operation of the refrigeration unit.
9. Proper handling; close the freezer when the door is open; shorten the time to open the door as much as possible; use strip curtains when loading and unloading the goods. Use partitions to separate dry goods (empty baskets) from perishable items.
In order to ensure the temperature of the cargo in the compartment, for urban distribution vehicles, it is recommended to use a strip curtain to ensure that the cold air in the compartment will not be quickly dissipated when the cargo is quickly unloaded (when the refrigeration unit is not closed). Cargoes of different temperatures are strictly prohibited to be stored in the same compartment space. They should be separated by partitions. Since the freezer is used to maintain the temperature of the goods, not to reduce the temperature, mixing goods with different temperatures will affect the temperature of the goods and cause the quality of the goods to be affected. Proper operation and use of refrigerated trucks is the key to ensuring the quality of temperature-controlled goods. It is also where the refrigeration equipment can work normally.