The so-called refrigerated container is a specially designed container with certain thermal insulation performance, which can maintain a certain low temperature and is suitable for refrigerated storage and transportation of various foods. The reefer container appeared in the late 1960s, with a light steel frame, with steel plates or light metal plates attached to the inside and outside, and the two plates are filled with thermal insulation materials. Commonly used thermal insulation materials are glass wool, polystyrene, foamed polyurethane, etc.
When changing the means of transportation, it is not necessary to reload and unload the food; the temperature in the box can be adjusted within a certain range, and there are ventilation holes on the box body, so it can adapt to the refrigerated transportation requirements of various perishable foods, and the temperature difference can be controlled within Within ±1°C, the influence of temperature fluctuations on food quality is avoided; the loading and unloading speed of refrigerated containers is fast, which significantly shortens the entire transportation time and reduces transportation costs. In addition, ground refrigerated containers have their unique advantages:
(1) Compared with railway refrigerated trucks, the flexibility of land transport refrigerated containers in terms of product quantity, variety and temperature is greatly increased. There are 20 refrigerated carriages in the large train and 10 refrigerated carriages on the small train. No matter how much cargo there is, there are only two choices, and the number of refrigerated containers can be increased or decreased at will; the temperature adjustment range of the railway refrigerated car is small, Moreover, the temperature inside the compartment of the ice-filled refrigerated truck is more difficult to control.
(2) Since the start and stop of the diesel generator is also controlled by the temperature in the box, the use of land transport refrigerated containers avoids the oil consumption of the diesel engine idling, so that the container does not need to be refueled during the 7-day operation.
(3) The box body of the land-use refrigerated container is light in structure and low in cost.
(4) It can maintain the quality of food to the greatest extent and reduce the loss during transportation. For example, when transporting fresh vegetables, the loss rate can be reduced from 30% to 40% of convertible vehicles to about 1%.
Refrigerated containers are specially designed containers with certain thermal insulation properties that can maintain a certain low temperature and are suitable for refrigerated storage and transportation of various foods. Refrigerated containers can be divided into railway, road, sea and aviation refrigerated containers according to the mode of transportation; according to the refrigeration method, they can be divided into thermal insulation, mechanical refrigeration plus cold source refrigerated containers, etc.
(1) Insulation container. The refrigerated container has good thermal insulation performance, without any refrigeration device, can not temporarily supplement cooling, and is suitable for short-distance transportation.
(2) External thermal insulation container. There is no refrigeration device in the refrigerated container, and the heat insulation performance is very strong. There is a hose connector at one end of the box, which can be connected with the refrigeration device of the ship or onshore cooling station, so that the cold air circulates in the container to achieve refrigeration. Generally, it can maintain the refrigeration temperature of -2~25℃. The refrigerated container is centrally supplied for cooling, has high volume utilization rate of the box body, light weight, and fewer mechanical failures during use. However, it must be shipped by a ship equipped with a special refrigeration device, and the temperature in the box cannot be adjusted independently during use.
(3) Built-in refrigerated containers. This is an incubator equipped with a refrigeration device. The refrigeration device provides a cold source. The refrigeration unit is installed at one end of the box, and the cold air is fed into the box from one end through a fan. If the box is too long, use the method of supplying air at both ends at the same time to ensure uniform temperature in the box. In order to strengthen the heat exchange, the cold air circulation method of sending down and returning up can be adopted.
(4) Liquid nitrogen and dry ice refrigerated containers. This kind of container uses liquid nitrogen or dry ice refrigeration to maintain the low temperature in the container, which is similar to the above-mentioned refrigeration method.