COLD STORE LOGISTICS
Ensuring an unbroken cold chain throughout the entire process of your goods movement
This article explains in detail the technical considerations of various areas of the typical cold room warehouse that are purpose built to store and handle food and products, such as meat, dairy, vegetables, fruits and other types of food where temperature preservation is important to preserve product integrity and freshness. It also highlights the various aspects and consideration of environmental protection and energy conservation, including the importance of equipping the premise with air tightness and heat preservation at all times. Special emphasis are also considered for negative temperature areas, where equipment should be free from icing and frost-free dew.
In short, the main function of Cold Room Logistics is to ensure an unbroken cold chain throughout the entire process of goods movement by the minimization OR elimination of cold air escaping from the environment AND ensure that energy is conserved as much as possible.
Loading Dock
We start with the loading dock, where refrigerated trucks dock to transfer or pick-up goods from and to their intended location.
Loading Dock Door
Typically, there will be an ante or staging room on the inside of the warehouse behind the loading dock. Depending on the type of warehouse, whether it is dedicated for a specific food product or various, this area would be kept at a temperature of anywhere from +5 to +20 deg C.
For cold-store where the door opens up directly to receive the goods from refrigerated trucks, an insulated door usually made of polyurethane filled foam, is the preferred choice for most installations. Depending on the nature of operations, this could be in the form of a standard PU sectional type overhead door with a sliding mechanism, or in cases where rapid opening and closing is desired, a Spiral motorized door, which offers more operational benefits especially in reducing cold air losses as well as operability of the door.
For maximum energy preservation, we recommend that the loading dock be configured with a combination of 80mm thick PU insulated lifting door + telescopic loading platform + inflatable door seal for the cold chain to handle all kinds of refrigerated trucks. The thermal conductivity U value [U value is a measure of how many watts (representing the rate of flow of energy) pass through one square metre (m²)] desired for cold chain should be in the region of K=0.63W/m2 K or lower.
Depending on the design of the warehouse and the temperature difference expected between inside and outside, an option would be to use a Dock House. In this concept, an external buffer area is created to accommodate the staging room before the goods enter directly into the main cold store areas. This has the added benefit of reducing temperature differences between areas and hence, cold air losses, as well as increasing overall energy preservation.
Typical loading dock area of a cold room with insulated PU doors
A cold store warehouse with external Dock House using a combination of Spiral Doors for fast opening/closing to reduce cold air losses and a PU Sectional Door for high insulation control
The Insulated Sliding Door
The sliding door is placed outside the platform and connected to the outermost wall. When the sliding door is closed, the entire loading and unloading port is in a fully sealed state, which effectively provides the role of thermal insulation and sealing to avoid cold air losses.
When the sliding door is opened, the door body slides upwards as a whole, depending on the height of the interior space of the building, and then turns 90° or rises vertically. The door body is made of hinged joints of multiple insulated door panels, and the sliding rails on both sides are made of galvanized steel. The pulleys are fixed to the sides of the door panel by a combination bracket. The wire rope wound on the drums at both ends of the shaft is connected to the bottom end of the door body, and the torsion bar spring balances the self-weight of the door body to ensure that the sliding door has no noise throughout its travel, and the sliding action is light and smooth.
Typical loading environment in a cold room warehouse. The entire loading area is sealed environment with the reefer truck to prevent cold air loss.
The Inflatable Dock Seal
The inflatable door seal is a product that connects the tail of the vehicle to the wall of the building. It’s main purpose is to seal the warehouse cold air from escaping as much as possible whenever the dock doors are opened. In this way, heat losses are kept to a minimum.
The door seal consists of an airbag constructed with side air curtain, top air curtain and a U-shaped elastic airbag at the front of the platform. The airbag material usually will be a heavy-duty polyester fabric with a minimum strength of 19-oz. and has high strength wear resistance and tear resistance.
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The airbags are inflated by an air blower that will maintain and balance the air pressure, keeping it as a continuous pressurized seal around the truck.
The door cover is equipped with 2 heavy-duty steel guards to protect the frame from damage to the frame caused by misalignment of the goods when the truck is reversed;
In cases where the loading dock is serving only one type and size of truck, such as corporate reefer containers, a Compression Type Dock Seal can also be used. It works by the compression of the truck edges into the compression pads as it reverse directly into the door opening and creating a tight seal that reduces cold air from escaping while at the same time, preventing insects, dust, dirt and foul weather from entering the warehouse. Its top pads are height-adjustable to suit trucks of different heights, making it a versatile choice for most cold stores or distribution centres with docks serving standard or refrigerated containers.
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Inflatable dock seal installation and application
Compression Dock Seal installation in a cold room warehouse
The Dock Leveler
The dock leveler serves as the bridge between the warehouse dock to the reefer truck for the material handling trucks to enter into the container for loading and unloading of goods. Besides bridging the gap, it can effectively compensate for the height difference between the truck and the building platform. When the truck is stopped near the platform, the deck of the dock leveler are raised by the electric hydraulic system and the lip is extended out to rest on the truck bed. Due to the higher gap caused by the inflatable dock shelters as well as the design of the warehouse insulation extension, a telescopic dock leveler is the best solution as the lip will have to bridge anywhere from 800-1000 mm distance, which is more than what the typical swing lip type dock leveler can handle.
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After the lip is extended and resting safely on the truck bed, the material handling vehicle can now directly enter the reefer container for loading and unloading operations, which is a safe and efficient process.
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A telescopic lip dock leveler with lips fully extended into the truck bed
Dock Safety System
To prevent premature truck departure and trailer creep, which can lead to accidents and employee injuries, truck restraint systems are recommended whenever a truck is parked at the loading dock.
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Trailer creep, also known as vehicle creep, is a situation where the trailer moves away, slowly, from the dock because of the ongoing impact of forklift traffic between the bed of the truck and the dock. This creates a huge gap putting both the forklift as well as the operator at risk.
Premature truck departure is a situation when the driver accidentally moves the truck away too soon from the dock before the loading activity is complete.
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As an added safety protection against truck backing into the wall accidentally, a H-type double steel column anti-collision structure can also be incorporated with steel channels supplemented by rubber bumpers (see picture).
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As many cold store warehouse interiors suffer from lower light conditions due to the enclosed environment, LED working lights may also be part of the dock facility.
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Insulated Cold Room Doors
Choosing the most suitable cold room door for your facility not only saves energy but also ensures trouble-free performance in the long run. The most important part of a well-functioning cold room is the right door with excellent sealing and insulation, as well as robustness in operation against cold elements such as icing and condensation.
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Door thickness is determined according to the temperature of the cold storage against the other side. Thickness can be 40 mm (for flip-flap doors), all the way to 160 mm for highly freezer environment up to -40 deg C. For these minus degree cold rooms; door seals are produced with heating resistance to protect the door against freezing. Customized dimensions are possible according to customer needs.
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We are able to offer a complete range of cold-room doors for the entire warehouse facility such as:
a) Fully Insulated Sliding Doors
b) Fully Insulated Hinged Doors
c) Fully Insulated Vertical Sliding Doors
d) Semi-Insulated Service Doors
e) Flip-Flap Doors
f) To & Fro Doors
g) Strip Curtains
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And many more.
For more information on Cold Room logistics, please contact us at our email on Home page.