Overview of reefer containers:
A container designed to transport frozen or low-temperature goods that require a certain temperature.
It is divided into a built-in mechanical refrigerated container with a freezer and an external mechanical refrigerated container without a freezer.
Suitable for loading meat, fruit, and other goods.
Refrigerated containers have higher costs and higher operating costs. Pay attention to the technical status of the refrigeration unit and the temperature required for the goods in the box.
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Classification of reefer containers:
According to the ISO/TC-104 668 Dimensions and rating standard, according to the length of the container, the container can be divided into 10′, 20′, 30′, 40′, 45′, 30′ containers, which are generally not used, and the most used length dimensions. Containers of 20′ and 40′, and now more than 95% of containers manufactured are containers of length 40′.
In recent years, 45′ containers have been used more and more, so the container of this size was added to the standard when the plate was changed in 2005.
According to the reefer container material, reefer containers can be divided into aluminum reefer containers and steel reefer containers.
Because the cost of aluminum reefer containers is relatively high, and it is easy to damage and has high maintenance costs, it was gradually eliminated after 2000. Now it mainly produces steel reefer containers.
Which shipping companies provide freezer services?
MSK, CMA-CGM, ONE, Hamburg Sud
Type of reefer container:
A refrigerated container refers to a container with insulated walls (including end walls and side walls), door, bottom and top of the box to prevent heat exchange between the inside and the outside.
Refrigerated containers include refrigerant-type refrigerated containers, mechanically refrigerated containers, refrigeration/heating containers, insulated containers, and air-conditioned refrigerated containers.
Refrigerant-type reefer container：
Refrigerant-type refrigerated containers refer to various refrigerated containers that do not require an external power supply or fuel supply, including water ice refrigerated containers, dry ice refrigerated containers, liquid nitrogen refrigerated containers, liquid air refrigerated containers, liquid carbon dioxide refrigerated containers, and cold plate refrigerated containers. Wait. The refrigerant-type refrigerated container is characterized in that it does not require an external power supply or fuel supply during transportation, without any moving parts, and has low maintenance requirements.
The main disadvantage is that continuous cooling cannot be realized. After the refrigerant is released and consumed, it must be refilled or replenished. It is difficult to achieve precise temperature control, and the refrigeration equipment takes up a lot of space. Coolant-type reefer containers are mainly used for short-distance transportation of small reefer containers.
Currently, refrigerant-type reefer containers are only used in regional short-distance refrigerated transport, but have no use in international refrigerated transport and are gradually being phased out.
Mechanically refrigerated container:
A mechanically refrigerated container refers to a refrigerated container provided with a refrigerating device (such as a compression refrigeration unit, an absorption refrigerating unit, etc.). Mechanically refrigerated containers are the most mature and widely used refrigerated containers. Compared with other refrigerated containers, they have the following advantages:
1 Wide temperature range, from normal temperature to about 30 °C can be adjusted. Highly versatile, capable of transporting goods of different temperature requirements;
2 automatic control is convenient;
3 box temperature distribution is more uniform:
4 Suitable for long-distance transportation, which is the most prominent advantage of its relative to other forms of refrigerated containers.
Mechanically refrigerated containers also have some shortcomings: such as complicated equipment, large initial investment, high maintenance costs; temperature gradient in the tank is greater than liquid nitrogen refrigerated container; fan and air duct system are required in the box, which will increase the dry consumption and dehydration of the goods in the box. .
Refrigeration heating container:
The refrigerating heating container refers to a refrigerated container provided with a refrigerating device (mechanical cooling or refrigerant cooling) and a heating device.
The container not only has a refrigerating device, but also has a heating device, and can adopt cooling or heating means as needed to control the temperature in the refrigerating container within a set range, and the general control temperature range in the box is 18 ° C to 38 ° C. .
Insulated containers are refrigerated containers that do not have any associated, temporarily attached refrigeration or heating equipment. The insulated container has good thermal insulation performance. In order to realize its heat preservation function, it must have external cooling or heating equipment to deliver cold air or hot air to the box to achieve the purpose of heat preservation.
The characteristic of the insulated container is that the structure of the box itself is simple, the effective loading ratio of the box cargo is high, and the cost is low.
Suitable for large-volume, same-type frozen or refrigerated goods on a fixed route. The disadvantage is the lack of flexibility and high requirements for the relevant facilities on the entire transport route.
Insulated containers were one of the main transportation tools for refrigerated fresh-keeping goods in the world before the 1970s. With the extensive use of mechanically refrigerated containers after the 1980s, insulated containers have gradually become more flexible machinery. Refrigerated containers are replaced, but are still used on certain routes with stable sources.
Air-conditioned refrigerated container:
The air-conditioned refrigerated container has all the cooling functions of the general mechanical refrigerated container and is equipped with a gas-conditioning device that can adjust and control the air content in the box to reduce the respiration intensity of fresh fruits and vegetables, thereby slowing the maturity of fruits and vegetables and achieving freshness preservation. the goal of.
The key to air conditioning is to regulate and control the content of various gases in the cargo storage environment.
At present, the most common method is to reduce the oxygen content in the environment by nitrogen filling and oxygen reduction, control the ethylene content, and slow down the ripening of fruits and vegetables. The airtightness of the air-conditioned reefer container is relatively high, and the general air leakage rate is not more than 2m3/h.
The use of air-conditioned refrigerated container transport has the advantages of good fresh-keeping effect, less storage loss, long shelf life and no pollution to fruits and vegetables.
However, due to the high technical requirements and the high price of reefer containers after the use of gas-conditioning equipment, the current use is not widespread.
Other reefer containers
In addition, there is a low-pressure refrigerated container similar to a modified-air refrigerated container, which stores fruits and vegetables in a low-pressure environment for storage and transportation.
The pressure inside the box is 1333~10666 Pa, the relative humidity is 90%-95%, and the temperature is 2 °C~+16 °C. The oxygen content is (0.1 ± 0.03)%, and ventilation is required to limit the ethylene.
And other harmful gases.
The low-pressure refrigerated container consists of a refrigeration system, a vacuum system, and a power system. The refrigeration system is used to reduce the temperature; the vacuum system is used to remove air and water vapor from the tank; the power system is used for diesel power generation for the use of electricity in containers.
The other is a jacketed refrigerated container, which is characterized by a channel for the circulation of cold air along the wall of the tank. The advantage of such a refrigerated container is that the loading of the cargo does not affect the circulation of the air and thus does not affect the temperature distribution;
Second, the entire volume of the jacket space is used to load the cargo, which is very advantageous for shipping low-density cargo. Such containers cannot be filled with respirable cargo and are generally used to ship frozen cargo.
Characteristics of reefer containers:
The reefer container is made of galvanized steel. The inner wall, bottom plate, top plate, and door are made of metal composite board, aluminum board, stainless steel board or polyester.
International container size and performance have been standardized.
The temperature range is -30 ° C ~ 12 ° C, the more common range is -30 ~ 20 ° C
According to the mode of transportation, refrigerated containers can be divided into sea and land.
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Advantages of reefer containers:
Refrigerated containers can be used for intermodal transportation of multiple transportation vehicles
Direct transportation from country to country can be realized from the place of origin to the point of sale.
Under certain conditions, it can be used as active cold storage.
In use, the whole box can be hoisted, the loading and unloading efficiency is high, and the transportation cost is relatively low.
The load capacity is high, the operation scheduling is flexible, and the using economy is strong.
The structure and technical performance of the new reefer container are more reasonable and advanced and have wide applicability.
The refrigerated container has the advantages of flexible loading and unloading, stable cargo transportation temperature, low cargo pollution, and low loss. It is suitable for a variety of vehicles, with fast loading and unloading speed, short transportation time and low transportation costs.
Operating precautions for reefer containers:
- After the reefer is loaded, the original quality of the refrigerated or frozen goods should be checked and stated on the manifest.
- In the process of packing, the principle of stacking and stacking should be strictly applied to avoid the imbalance of cooling caused by cold wind short circuits and reduce the cooling efficiency of the refrigeration unit.
- When the frozen goods are transported for a long distance, the difference between the set temperature and the set temperature in the box shall not exceed 3 °C. If the cooling goods are shipped, the temperature error should be no more than 0.5 ° C, preferably no more than 0.25 ° C.
- Containers carrying fresh fruits, vegetables, etc., should open the fresh air outlet in time to ventilate and ventilate. However, when transporting frozen goods, the fresh air vent should be closed.
- When transporting the cooled goods in the carton pack, it should be ventilated in time according to the outdoor air temperature and humidity to keep the air in the box dry and prevent the outer surface of the package from condensation.
6 Refrigerated containers are usually used at temperatures not higher than -18 °C when transporting frozen goods. Usually the average temperature of the frozen container is 31.3 °C / h (empty box); but after loading, due to the large heat capacity of the cargo, the cooling rate will be greatly slowed down, sometimes it takes 15-16h to reach the set temperature requirement.
If the purchase temperature is high, it takes 2-3d to reach the set temperature.
The temperature rise and fall speed in the refrigerated and frozen container box are related to the cargo loaded in the box. When the set temperature range is -18 °C ± 3 °C, the temperature inside the box should be kept stable.
However, when calculating the temperature rise in the tank when the refrigerator is not cooled, the following empirical formula can be used as the standard value calculation.
1) Cooling goods (when not ventilated) 0.0054*(tw-tn)°C/h
2) Frozen goods 0.0067*(tw-tn) °C/h
In the formula, tw and tn are the ambient temperature and the temperature inside the tank, respectively.
The main loading items and application areas of reefer containers:
Food: meat, fish, aquatic products, biscuits, chocolate,
Chemical products: mainly fine chemical products; such as perfumes, air fresheners, plastic products
Transport closed containers of fresh fish, fresh meat, frozen foods, and fruits, vegetables, films, medicines, etc. that need to maintain a certain temperature. There are two types of refrigerated containers and insulated containers.
(1) Refrigerated containers are generally provided with a built-in freezer at the front end of the box. When the freezer is working, the cold air is blown out from the air vent at the rear end of the box through the gap between the ridges on the wall of the box and the ventilating guide at the bottom of the box, and passes through the cold air suction port on the front wall to return to the freezer for looping. In order to improve the cooling effect, the inner wall of the entire refrigerated container, the top of the box and the inside of the bottom of the box are covered with insulating material. The working temperature of the refrigerated container is between -28 °C and +26 °C. According to the needs of the goods, the temperature inside the box can be adjusted automatically.
(2) The insulated container is mainly used for loading fresh fruits such as fruits and vegetables. Generally, a cold agent such as dry ice is used to prevent the temperature inside the box from rising excessively, and the usual holding time is about 72 hours. There is a full heat-proof structure around the box and above and below.
The difference between refrigeration and insurance for reefer containers:
- Refrigeration mode
Set the temperature below -5 ° C (Note: different units are slightly different), such as -18 ° C. The unit uses the return air temperature as the control temperature
- Preservation mode
The set temperature is higher than -5 °C (Note: different units are slightly different), such as +2 °C. The unit uses the supply air temperature as the control temperature.
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Refrigerated container temperature unit °C and °F conversion:
°C = (°F-32 ) x 5/9
°F = °C x 9/5 +32
The operation process of reefer container:
The loading time of reefer containers:
Because the freezer needs pre-cooling and testing, it is necessary to arrange the trailer in advance to ensure sufficient time for booking/PTI/pre-cooling/to the factory. At the same time, consider the dock-free period, and the return time cannot exceed the free-up period. If the packing is in a remote location, you need to make the appropriate time adjustment.
- PTI (Refrigerated Container Inspection): It takes 4 to 8 hours for a shipping company to do PTI.
- PRE-COOL (pre-cooling): The shipping company usually takes 8 to 12 hours.
- Free stacking period: The general shipping company is exempted from the stacking period of 3 days (that is, including the first 3 days of the customs clearance date, but some shipping companies are estimated by the shipping date), so it must be confirmed with the shipping company before booking…
- Free box: The general container company’s free box rental period is 3 days.
PTI: PRETESTING INSPECT (pre-cooling)
CWI: CARGO WORTHY INSPECTION
Cut off time:
Ensure that there is enough time for customs clearance, boarding, and responding to emergencies.
- At least one day’s customs clearance time is required for customs clearance at the customer’s place of origin and then customs clearance.
- If the customer is in customs clearance, they need to reserve two to three days of customs clearance time.
Special case handling: If there is an unexpected incident in the afternoon of the customs clearance day (such as customs check cabinets, etc.), if you cannot release the goods on time, you need to apply to the shipping company for the time of delaying the retraction, and confirm with the shipping company. The exact time of the boat. If the ship will sail in the afternoon or evening of the next day, it is very hopeful to apply to the shipping company to extend the time of retraction until noon or afternoon of the next day (because the shipping company will generally find a way to minimize the refrigerated Container on board).
The name of the reefer container and the gross weight of the goods:
- Bookings to the shipping company must provide detailed goods, preferably in Chinese and English. If the customer cannot provide the exact name under special circumstances, then at least the category of the goods, such as fruits, vegetables, seafood, beef Meatballs, fish balls, silk cocoons, etc.
- The shipping company needs to provide the gross weight of the cargo at the time of booking. Because some ports have limited requirements, such as South Korea’s BUSAN requires that the gross weight of the cargo cannot exceed 23 tons.
Refrigeration container temperature and ventilation:
(1) The adjustable temperature range of the freezer is generally between minus 21 degrees Celsius and plus 18 degrees Celsius.
(2) The adjustable ventilation range of the freezer is about 0CBM/HOUR~~240CBM/HOUR.
(3) In order to ensure the safe storage and transportation of frozen goods, it is necessary to carefully confirm the requirements of temperature, ventilation, and pre-cooling when ordering. In general, frozen goods (below 0 °C) do not need ventilation. Only refrigerated fresh-keeping goods (fruits and vegetables with fresh goods above 0 °C) need ventilation.
Commodity inspection, customs declaration requirements, CWI for reefer containers
CWI: General trade clearance is required in Shenzhen. Generally, CWI is required; if it is closed at the place of origin and then transferred to Shenzhen, the general situation should not be CWI, and it must be confirmed with the customer.
- CWI single: This order is issued by the yard of the cabinet, and the unit price is generally 180 RMB/cabinet (reference data).
- CWI original: This order needs to be taken to the Commodity Inspection Bureau for replacement. Some shipping companies can apply for the CWI original directly to the Commodity Inspection Bureau, but they need to apply to the shipping company for this service two working days before the freezing cabinet time.
The shipping companies that currently provide this service are OOCL, YML, etc. The cost of doing this service by the shipping company is about 425 RMB/cabinet (reference data).
Trailer shipping confirmation for reefer containers
In the peak season, it is generally necessary to reserve a car with the team 3 days before the cabinet, as far as possible to avoid the situation of no car.
Booking of reefer containers
Fill in the booking form and send it to the owner according to the ship owner’s request. Please note the following:
1) Schedule / Port of Port / Port of Destination
2) Ventilation / temperature / CWI
3) Do you need pre-cooling/carrying time?
4) Requirements for reefer containers (whether defrosting)
5) Cabinet type / cabinet volume / goods
Booking confirmation for reefer containers
Notify the customer that the booking and trailer have been arranged, including:
- Booking information: schedule / cabinet / POL / POD
- Trailer information: Confirm the time of the cabinet/trailer and driver information (or after the time)
Refrigerated container loading:
- Inform the driver that the whole process should be frozen during the transportation process. If the vehicle generator fails during the transportation process and cannot be normally cooled in the freezer, the team is required to immediately inform the team to take remedial measures immediately (such as repairing the generator and changing the vehicle). Wait).
- Keep an eye on the loading dynamics: whether to arrive on time and the loading progress.
Refrigerated container declaration:
If there is an unexpected incident in the afternoon of customs clearance (such as customs check cabinets, etc.), if you cannot release the goods on time, you need to apply to the shipping company for the time to delay the retraction, and confirm the exact time of the ship to the shipping company. .
If the ship will sail in the afternoon or evening of the next day, it is very hopeful to apply to the shipping company to extend the time of retraction until noon or afternoon of the next day (because the shipping company will generally find a way to try to let it freeze) The ship on the cabinet). At the same time, the actual situation of the customs declaration will be promptly fed back to the customer.
Bill of lading, bill confirmation and delivery of reefer containers
Note for this phase:
- Due to the high risk of the freezer, it is generally recommended that the customer leave the ship to the east, which can also reduce the risk of the freight forwarding company.
- When approaching the ocean route, it is recommended that customers use the delivery form of the ship’s single-discharge. Since the freezer is relatively short in the destination port (free of the stacking period of 1~3 days), the shipowner’s electric discharge is convenient for the consignee to smoothly and quickly handle the procedures at the destination port.
- Under normal circumstances, the near-ocean route needs to transmit the relevant information to the agent at least one day before the arrival of the goods to the agent; the ocean-going route needs to transmit the relevant information to the agent 3 days before the arrival of the goods.
The customer base of reefer containers is divided into the following three types:
1 aquatic product importer
2 agricultural products importers
3 fruit importers
5 Pharmaceutical Importers
Temperature, ventilation and humidity standards and requirements for different products of reefer containers?
The temperature of the reefer container can be set between -35 and +30 degrees, but the usual cargo temperature is between -23 and +12 degrees.
Aquatic products are usually at (-18 to -23 degrees)
Agricultural products (preservation between -3 degrees and +12 degrees. Frozen products at around -18 degrees)
Juice products (usually between 0 and +5 degrees, with some exceptions)
Chemicals (usually freezing temperature, because there are fewer such goods, no specific date can be referenced)
Ventilation usually occurs on fresh-keeping goods, and the chilled goods are ventilated closed. Such as fresh garlic, ginger, etc., ventilation is open.
Humidity can now be set, but will not be displayed on the bill of lading
Vents are not allowed when loading frozen goods.
Vent opening units CMH and CFM
Daily maintenance of reefer containers:
The following principles are subject to:
- Working condition of the refrigeration unit.
- Check the recording accuracy of the temperature control probe.
- Check the measurement accuracy of the temperature recorder probe and the recording device (if assembled).
4, the box inspection and repair, including the door seal and floor drain seal, should be carefully maintained to prevent air leakage. Prevent garbage, moisture, and odors from entering.
All internal and external panels must be repaired to prevent moisture from penetrating into the insulation layer and causing insulation failure. Under normal circumstances, the insulation layer will be 5% annual failure, and the annual fuel consumption will increase.
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Precautions for refrigerated containers, before loading, at the time of loading, during transportation, and during unloading:
Precautions before loading reefer containers:
- Ensure that the refrigeration unit is set correctly for the loaded goods, the function is normal, and the control temperature meets the requirements.
2, defrosting, if the operator does not know, such as defrosting may damage the goods.
- All pre-shipment inspections are required for all refrigeration equipment.
- Transportation should be clean and free of odors, especially before loading meat, meat, fish and cheese products.
Precautions when loading reefer containers:
- The refrigeration unit should be shut down during packing to avoid wasting energy and avoid condensate. Pack as fast as possible
- If the packing process is interrupted, close the door and open the refrigeration unit.
- Check the temperature of the goods with a precise thermometer (if conditions permit). Several cargo temperatures were measured at random and recorded on the packing slip.
- Record the following damage: damaged packaging or mechanical damage to the goods. Any odor goods or packaging exceptions should be recorded.
According to the usual method or according to the owner to introduce the stacking goods, when transporting the goods that will be breathed, the air must be allowed to circulate between the packages, leaving a gap of not less than 10CM from the top plate in the upper part of the cargo. Do not hold the carton against the side panels. If the goods do not reach the full width, they should be overlapped.
- Leave a small gap between the trays when loading the tray.
- For the bottom air supply load, cover the floor with a smooth cardboard box or board to force air through the cargo to prevent bypass.
- When transporting mixed fruits and vegetables, choose a higher cargo temperature than a lower one.
- Do not accept the cargo of the owner who needs to be cold in transportation without leaving a ventilation gap.
Precautions in the transportation of refrigerated containers:
- The refrigeration unit should be operated continuously except for the barge or control noise area.
- Check the temperature controller settings and the defrosting interval at startup.
- Observe the indicated temperature, alarm light status and defrosting operation.
Precautions when unloading reefer containers:
- Keep the machine running before opening the door.
- If the goods are damaged, make sure to record the loading position of the goods, which is useful for distinguishing the causes of damage.
- Check the temperature of each part of the package.
- Do not accept goods that may contaminate the means of transport or cause food spoilage.
At present, many goods are packed by the shipper. Sometimes the goods are found damaged at the port of destination, but the container is in good condition and the machine works well throughout the transportation process.
And this may be caused by improper cold boxing caused by improper packing. Keep in mind the instructions for the operation of refrigerated containers, which will help the safe transportation of goods.
Summary points again:
1 When avoiding loading, turn on the air-conditioning, which may cause the moisture in the air to freeze on the low-temperature evaporation coil, which will affect the cooling effect.
2 Avoid the goods from crushing the deflector.
3 It is strictly forbidden to block the return air outlet.
4 The stacking height of the cargo should not exceed the loading line
5 Cargo pre-cooling The cargo should be pre-cooled and pre-cooled to the temperature required for transportation. Due to the limited cooling capacity of the refrigerated container, it can only be used to maintain the temperature of the cargo. If the temperature of the cargo is too high, the refrigeration system will be overloaded, causing the system to malfunction and affecting the safety of the cargo.
6 Refrigerated container pre-cooling In general, the refrigerated container should not be pre-cooled. As the pre-cooled refrigerated container opens the door, the outside hot air enters the refrigerated container. When it is cold, it will generate condensation, which will damage the outer packaging and label of the goods. The condensation of water on the surface affects the amount of refrigeration. However, when the temperature of the cold storage is the same as the temperature in the reefer container and the “cold air channel” is used for loading, the reefer container can be pre-cooled. When the refrigerated container is shipped with temperature-sensitive goods, the refrigerated container should be pre-cooled, and the door should be closed when pre-cooling.
7 Before packing and loading, please pay attention: the set temperature should be correct; the set fresh air exchange rate should be correct; the set relative humidity should be correct; the refrigeration system should stop working when packing; The cargo shall be lower than the red loading line and the vertical surface of the T-slot; the cargo stacked in the box shall be firm and secure; the total weight of the cargo in the container shall not exceed the reefer container* large allowable load; reefer container The total weight (including the weight of the attached equipment) after loading shall not exceed the limit of any passing country during transportation.
Cargo packaging requirements for reefer containers:
Perishable fruits and vegetables should be packaged to allow air to circulate in the middle of the cargo and carry away the gases, moisture, and heat generated by the respiration of the cargo.
The packaging of the goods should have sufficient strength and good physical properties to work properly in high humidity environments. Carton, wooden crates and another internal packaging for packaging goods must allow vertical airflow
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How to avoid loss in reefer container transportation?
A large part of the claim for reefer container transportation is from the cargo claim. The reason for the claim is usually that the set temperature is not maintained during transportation, resulting in the loss of the goods.
Guide to the loading process and requirements of reefer containers and the transport of reefer containers
The ship shall be equipped with refrigerated spare parts, tools and maintenance manuals for the manufacturer of the relevant refrigeration equipment. These tools and facilities should be used by shipboard engineers when emergency repairs are required during the voyage. There are different types of refrigeration equipment, each with its own repair and maintenance features.
The amount of refrigerant supplied should be based on the type and quantity of the reefer on board.
It is important to obtain a detailed description of all shipping conditions from the shipper prior to shipment, including temperature, ventilation and humidity requirements. International Cold Chain Technology (ICCT) recommendations for shipping conditions are available on the ICCT website.
If the ship is loading at the port of loading, the inspector shall be assigned to monitor the temperature at which the goods arrive and indicate any details that are inconsistent with the requirements of the instructions.
Any special requirements relating to refrigerated transport in the lease, such as monitoring procedures, repair requirements, parties to be notified in the event of a failure, etc., shall be strictly observed and appropriate instructions shall be made to the ship in writing.
The vessel should contain a refrigerated operating manual that clarifies the conditions of transport for refrigerated loads, possible problems, and an overview of the problem-solving procedures. If the problem is not covered in the manual, expert advice should be sought.
At the beginning of loading, the crew should reconfirm whether the ship’s power outlet and the reefer’s plug are matched and the quantity is sufficient for all loaded reefer containers. If necessary, prepare a sufficient number of conversion plugs.
To prevent a power outlet from malfunctioning, a spare refrigerated extension cord should be provided.
After the reefer container is turned on, apply a locking ring to lock the plug and socket. It should also be checked to ensure that the refrigerated outlet box is completely closed to prevent water from entering during the voyage.
After the refrigerated container is loaded and the power is turned on, an experienced crew member should be arranged to check that the refrigerating unit is running and the temperature is gradually reaching the set value. If the refrigeration unit is not operating, basic inspection measures should be taken.
Many of the claims for refrigerated cargo area due to confusion between Fahrenheit and Celsius, as well as positive and negative temperatures. After the refrigerated cargo is loaded onto the ship, care must be taken to ensure that the temperature is set correctly. If there is any difference between the actual temperature setting and the cargo shipping instructions, they should be reported immediately.
During the voyage, the refrigerated temperature should be checked at intervals not exceeding six hours. The inspection time, as well as the supply and return air temperatures, are recorded each time. In case of any problems, the details should be recorded in the appropriate record book. In addition, automatic recording can transmit the relevant signals to the center point via the cable. The system should be checked regularly to avoid error messages.
How to control temperature and defrosting in refrigerated containers
During the operation of the refrigeration unit, an ice layer is formed on the evaporator coil, depending on the set temperature, the temperature of the cargo, the amount of fresh air in the ventilator, and the humidity of the cargo.
The refrigeration unit periodically enters a defrost state, generating heat from a series of electric heating devices or blowing hot air into the evaporator coil.
All fans will stop rotating at this point to prevent hot air from entering the cargo hold. However, since the return air temperature sensor position is close to the refrigeration unit, such temperature rise may be recorded.
Therefore, unless processed by the data logging software, the temperature record will exhibit a periodic temperature rise consistent with the defrost interval. If the defrosting period is short, there may be some discrepancies between the hourly temperature reading and the defrosting period.
It should be noted that this increase in temperature reading does not immediately affect the actual temperature of the cargo, nor does it mean that the refrigeration unit is in an unstable state.
In addition to temperature, electronic data records usually show the defrost interval and duration. If the loading temperature exceeds the set temperature, the refrigeration unit will automatically begin to reduce the temperature of the cargo to the desired temperature level.
If the cargo has been thawed, the chiller will attempt to lower the temperature of the cargo but will continue to defrost frequently.
In addition to the set value of the cargo and the supply and return air temperatures, the temperature control system provides detailed information about the system problem in the form of an error code.
The temperature of the cargo can be recorded by the US Department of Agriculture (USDA) detector, which is installed to comply with the US Department of Agriculture’s refrigeration process for fruit shipments.
The data logger placed by the shipper in the loaded cargo also records the general temperature. When the refrigeration unit fails, the temperature display and data recording will show a gradual steady temperature rise until the final ambient temperature value is reached.
Again, the sensor only records the air temperature, not the temperature of the cargo. The cargo will be protected by the surrounding insulation material to prevent exposure to outside air temperatures.
Refrigerated containers because of the ocean freight rate of each shipping company’s pricing rules vary greatly, seasonal floating is relatively large, if you want to get the most favorable reefer container offer, welcome to send an inquiry to Bestforworld.
We operate a large number of refrigerated containers shipping from China to Japan, Korea, Malaysia, South Africa, Indonesia, Pakistan, Russia, Mexico, Vietnam, Germany, Egypt, Turkey, and Thailand.
At the same time, Bestforworld also handles cargo importing from the United States, Argentina, Chile, Mexico, Canada, Spain, Italy, South Korea, Taiwan, Malaysia, Vietnam, Cambodia, Thailand, Indonesia, India, the Philippines, etc. into China.
Because the operation requirements of the refrigerated cabinet are extremely high, even in Google, it is rare to find complete and detailed instructions for the operation of the refrigerated containers. This article will greatly facilitate the importer to purchase products from China and solve the logistics difficulties.
It will also help more Chinese buyers to import more products from overseas to China.
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