The correct operation of refrigerated trucks and their cargo risk management

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1. Proper operation ensures that the goods can be stored and transported in good condition.

Only the correct use and operation of a refrigerated truck can guarantee the complete delivery and preservation of the goods. Because refrigerated trucks are used exclusively for temperature-sensitive products, the guarantee of temperature is the key to refrigerated trucks. Improper use or improper operation can result in the goods not being stored or shipped in good condition.

2. Preventive maintenance can minimize maintenance and operating costs.

In our normal use, maintenance and maintenance of vehicles and chillers are inseparable. Only when the equipment is properly maintained and maintained on time, the normal use of the equipment can be guaranteed and the service life of the equipment can be extended. Usually, the chassis engine is maintained and maintained according to the mileage, while the refrigeration unit is designed to maintain and maintain according to the engine operating hours. The usual refrigeration unit is 500-700 hours for maintenance and maintenance. It needs to replace the oil filter, fuel filter, and air filter; and pay attention to check the tightness of the belt, the refrigeration system has

No leakage, etc. However, in order to meet environmental protection requirements, individual brand refrigerating units (such as the American Cold King) have to minimize damage to the environment and reduce the emission of harmful substances, so synthetic or semi-synthetic motor oils are used instead of ordinary motor oils. Extend the maintenance time of the engine, usually do maintenance once every 2000 hours. As a result, the waste of used motor oil is reduced. In addition, scientific experiments show that by using this high-end engine oil, not only the wear of 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 equipment, but also reduce operating costs.

3, suitable packaging is essential to protect the goods.

For non-ventilated containers for refrigerated goods, side-ventilated containers for fresh produce. The box must be compressive.

Because the frozen goods do not allow the wind to blow from the surface, because the wind blows over the surface of the frozen goods, the moisture in the goods will be lost and the quality of the goods will decline. This year, our country's formulation of bulk frozen foods will not be allowed to sell. There must be packaging sales. Due to its own characteristics, fresh products are still in a breathing state during storage and transportation. If they are not well ventilated, the goods will be deteriorating. Therefore, it must be ensured that such goods have good ventilation and ventilation.

4. Set the thermostat to the desired temperature and prechill the car for 1.5 hours to drain the heat left in the car; when loading, the refrigeration unit will be turned off and the cargo will be loaded quickly.

When loading, the compartment must be pre-cooled or warmed up. Because the vehicle is parked in the open air, the temperature of the passenger compartment is usually the ambient temperature. If the temperature of the conveyed goods is not ambient temperature, the goods are loaded into the car, and the ambient temperature will affect the temperature of the goods being transported, resulting in a change in the quality of the goods being transported. Therefore, the car must be pre-cooled to the required temperature before loading. However, the refrigeration unit must be turned off at the time of loading (unloading). Many people do not shut down the refrigeration unit when loading or unloading goods. In fact, this is a very wrong operation.

The reason is: When we precool the cabin, if it does not shut down, open the door of the car, because the fan of the evaporator of the refrigeration unit is working, the front of the fan is positive pressure, and the back is negative pressure, so the cold air from the upper part of the car Blow out, while the lower part will quickly inhale hot air from outside, resulting in a rapid rise in the temperature inside the compartment; if you load and unload cargo after the shutdown, because the fan is stopped, the air flow stops, the air pressure inside and outside the compartment is the same, which makes the external heat The speed at which air passes into the cabin is relatively slow.

5, the goods must be pre-cooled to the required temperature, check the temperature of the goods when loading; refrigeration unit is used to maintain the temperature of the goods, rather than to reduce the temperature of the goods.

Many users of refrigerated trucks have a wrong concept. It is always believed that the refrigerating unit on a refrigerated truck can freely freeze or heat the cargo loaded into the carriage to its desired temperature. Therefore, the goods that are insufficient for the transport temperature are loaded into the carriage, and the refrigeration unit is set to its required transportation temperature, and the temperature of the cargo is lowered or raised to its desired temperature over a certain period of time. However, the opposite is true. Not only does the temperature fall (or does not go up), the cargo damages or deteriorates. Because the refrigeration unit of a refrigerated truck does not lower the temperature of the goods, but maintains the temperature of the goods, he packs the goods just like the quilts we used to sell cold drinks. When the external cold (heat) source passes radiation, conduction, and convection into the cabin, it is carried away by the cold air blown by the refrigeration unit and the heat source is cut off from the cargo.

Therefore, at the time of loading, 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, the temperature of the cargo in the compartment is difficult to reach the required temperature for transportation. The storage temperature and the transportation temperature of the goods must be the same. If the temperature of the goods changes frequently, the water will be lost, which will cause the quality of the goods to change, which will lead to a shortened shelf life of the goods.

6. Even if the capacity of the unit exceeds the actual requirement, insufficient air circulation will be the main reason for the deterioration of the goods; any obstruction around the cargo may lead to “hot spots”.

A qualified refrigerated truck must ensure that there are 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 goods are transported under the proper temperature requirements. The cold (hot) gas blown by the refrigeration unit isolates the cold (hot) source that enters the compartment from the outside and protects the cargo. If a blockage occurs at one location, the cold (heat) source in this section will directly enter the item, causing the cargo temperature to change. Make sure that the return air shutter is in good condition; do not block the inlet of the evaporator (return air); insufficient return air will cause irregular circulation of the cold air and cause the top cargo to freeze.

7. The goods must be stacked on double-sided pallets; the fresh-keeping pallets must not contain the picking film, and the film will block the circulation of cold air to the goods; the floor under the goods cannot be blocked.

The general refrigerated truck floor uses vented aluminum rails; however, some refrigerated trucks do not have aluminum rails, and flat anti-skid floors are used. The non-slip floor is usually used as a third-party transportation company or a company transporter for dairy products. The purpose is to be suitable for the transportation of multiple products or to facilitate the cleaning of the ground. However, it must be noted that the loading must be done with double-sided pallets to ensure the circulation of cold air on the ground. It is forbidden to stack goods directly on a flat floor.

8. Do not stack cargo in front of the evaporator outlet, otherwise it will impede the cold airflow; obstruction above the cargo will cause a short circuit in the cold airflow. Maintain a minimum distance of 225 mm between the top of the cargo and the roof.

When loading, do not stack the cargo too high. Make sure that the loading height is not higher than the level of the 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 in the compartment normally, thus causing the local temperature of the cargo to rise.

On the other hand, some defrosting designs for the refrigeration unit use air-induced 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-sensitive switch will immediately operate, the unit will quickly enter the defrosting state; when the coil temperature rises to 9 degrees (design temperature) About, defrosting ends immediately. As a result, the above-mentioned operation of the unit will be reciprocated, resulting in a phenomenon in which the temperature in the passenger compartment does not fall. The only feeling for everyone is that the crew always defrosts frequently. In fact, it was caused by too much (more) cargo.

9. The interior of the carriage must be kept clean; there should be no wrapping paper or paper scraps on the ground; debris can impede the flow of air or be inhaled by the evaporator.

When using a refrigerated truck, the floor of the carriage should be kept clean. Due to the effect of the evaporator fan, air circulates in the compartment, causing ground shreds or dirt to be drawn into the evaporator fan. For a long time, a large amount of impurities will be sucked into the evaporator coil, affecting the cooling effect of the refrigeration unit. Because the coil is surrounded by a little bit of impurities, the heat exchange rate of the coil decreases. Therefore, after a few years of use, refrigerated trucks will feel that the cooling effect is worse than the beginning. Besides the cause of the malfunction, it is because the coils are too dirty. Therefore, ensuring the cleanliness of the ground in the carriage is the key to ensuring the normal operation of the refrigeration unit.

10, properly handled; when the door is opened, the freezer should be closed; shorten the opening time of the door as much as possible; use bar-shaped curtain as much as possible when loading and unloading goods. Use partitions to separate dry goods (empty baskets) and perishable items.

In order to ensure the temperature of the goods in the carriage, for the delivery vehicles in the city, it is recommended to use a strip curtain to ensure that when the cargo is unloaded rapidly (when the refrigeration unit is not closed), the cold air in the carriage will not be quickly lost.

Different temperature goods are forbidden to be stored in the same compartment space. Should be separated by partitions. Because the freezer is used to maintain the temperature of the goods, not to cool down, mixing goods of 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 also ensures that the refrigeration equipment can work properly.

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