Points for the correct use of refrigerated trucks

How should a refrigerated truck be used correctly? How to avoid the risk brought about by improper use? 

In our normal use process, only by regularly maintaining the equipment correctly can we ensure its normal use and extend its service life.

Usually, the chassis engine maintenance is based on mileage, while the refrigeration unit maintenance is based on the engine operating hours.

The refrigeration unit requires maintenance and servicing every 500-700 operating hours. This includes replacing the oil filter, fuel filter, and air filter. It is also important to check the tightness of belts and inspect the refrigeration system for any leaks.

However, some brands of refrigeration units have adopted synthetic or semi-synthetic oils instead of regular oils to minimize environmental impact and reduce the emission of harmful substances. This allows for longer maintenance intervals, typically around 2000 operating hours, thus reducing the disposal of used oil. Additionally, scientific experiments have shown that using these high-end oils not only reduces engine wear but also decreases fuel consumption. Therefore, proper and scientific maintenance not only ensures equipment integrity but also reduces operational costs.

For frozen cargo, non-ventilated packaging containers should be used, while for fresh goods, side-ventilated packaging containers are preferred.

The packaging containers must be resistant to compression. This is because in the case of frozen goods, it is not permissible for air to blow over their surfaces. The wind blowing over the surface of frozen goods can cause moisture loss, leading to a decrease in product quality. On the other hand, fresh goods, due to their inherent characteristics, are in a respiratory state during storage and transportation. If proper ventilation is not provided, the goods can spoil and deteriorate. Therefore, it is essential to ensure good ventilation and air exchange for such goods.

During loading, it is necessary to pre-cool or pre-heat the cargo compartment. This is because vehicles are typically parked outdoors, and the temperature inside the cargo compartment is usually the same as the ambient temperature.

If the temperature of the goods being transported is different from the ambient temperature, loading them into the cargo compartment without pre-cooling or pre-heating can result in temperature changes that affect the quality of the goods during transportation.

Therefore, it is essential to pre-cool or pre-heat the cargo compartment to the required temperature before loading. However, during the loading and unloading process, the refrigeration unit must be turned off.

The refrigeration unit in a refrigerated truck is not intended to lower the temperature of the goods but rather to maintain their temperature. It acts as a protective layer, similar to a blanket we used in the past when selling cold drinks, to wrap the goods. When external cold (or heat) sources radiate, conduct, or convect into the compartment, the cold air blown out by the refrigeration unit carries away the heat, effectively isolating the goods from the heat source.

Therefore, during loading, it is essential to measure the temperature of the goods being loaded. If the set temperature of the refrigeration unit is higher or lower than the temperature of the goods, it will be challenging to achieve the required transport temperature inside the cargo compartment. The storage temperature and transport temperature of the goods must be consistent. If the temperature of the goods fluctuates frequently, moisture loss can occur, resulting in changes in the quality of the goods and a reduction in their shelf life.

A qualified refrigerated truck must ensure good ventilation on all six sides of the cargo compartment, with no obstructions on any side of the goods. Proper air circulation is essential to ensure the transportation of goods at the appropriate temperature requirements. The cold (or hot) air blown out by the refrigeration unit acts as a barrier, isolating the external cold (or hot) sources from entering the cargo compartment and affecting the goods. If there is a blockage at any position, the cold (or hot) source can directly enter the area and cause temperature changes in the goods. It is important to ensure that the return air baffle is in good condition and that the inlet (return air) of the evaporator is not blocked. Insufficient return air can result in irregular circulation of cold air and cause ice formation on the top of the cargo.

The goods must be stacked on double-sided pallets. Fresh goods should not be wrapped with stretch film on the pallets as the film can obstruct the circulation of cold air to the goods. 

Generally, refrigerated trucks have floors with ventilated aluminum railings. However, some refrigerated trucks have flat non-slip floors. These flat floors are commonly used by third-party transport companies or companies transporting dairy products. The purpose is to accommodate the transportation of various products or facilitate floor cleaning. However, when loading, it is crucial to use double-sided pallets to ensure proper airflow circulation on the floor. It is strictly prohibited to stack goods directly on the flat floor surface.

When loading, it is important not to stack the goods too high, ensuring that the loading height does not exceed the level of the air outlet. If the air outlet is blocked or too close to the goods, it can not only affect the storage temperature of the goods but also hinder the proper functioning of the refrigeration unit. When the air outlet is blocked by goods, the cold (or hot) air cannot circulate properly within the cargo compartment, resulting in an increase in temperature in that specific area. Additionally, some refrigeration units have an air-induced defrosting design.

When using a refrigerated truck, it is important to keep the cargo compartment floor clean. Due to the action of the evaporator fan, air circulates inside the compartment, which can cause debris or dirt on the floor to be drawn into the evaporator fan. Over time, a large amount of impurities can accumulate inside the evaporator coils, affecting the refrigeration unit's cooling efficiency. Ensuring cleanliness of the cargo compartment floor is crucial for maintaining the proper functioning of the refrigeration unit.

To maintain the temperature of goods inside the cargo compartment, it is recommended to use strip curtains for local delivery vehicles. This helps to prevent rapid loss of cold air from the compartment when unloading quickly without turning off the refrigeration unit. It is strictly prohibited to store goods with different temperatures in the same compartment space. They should be separated by partitions. Since the refrigeration unit is designed to maintain the temperature of the goods rather than cool them down, mixing goods with different temperatures can affect the overall temperature and compromise the quality of the goods.

Proper operation and use of refrigerated trucks are crucial for maintaining the quality of temperature-controlled goods and ensuring the proper functioning of the refrigeration equipment.