WO2003013318A1 - Cold storage box - Google Patents

Abstract

A cold storage box consists of a combination of two main parts, which allows the transportation of chilled or frozen goods by post. It includes: Insulation. The insulation used in the three pieces: Top, bottom and the four sides in one piece. Multiple layers of flexible sheet plyethylene are used to make different thicknesses for different performance requirements. Cooling Elements. These are frozen and put inside the insulation. Brime filled cooling elements are used to keep the pemperature below zero or water filled cooling elements are used to keep the temperature slighly above zero. Frozen: a pre filled plastic bag with 1 litre of brine (salt solution). Each contains 0.33 to 0.37 kg of salt per litre of water to give freezing temperature of around 18 to 20 celsius. Chilled: a pre filled plastic bag with 1 litre of water and some chlorine

Description

COLD STORAGE BOX

Detailed Description

1.0 INTRODUCTION

The Fridge e Wrap is a novel idea designed to keep products frozen or chilled for a specified period of time. This detailed description describes the generic product.

The Fridge e Wrap Frozen. This product maintains frozen temperatures for x hours with an ambient outside temperature of 20 degC.

The Fridge e Wrap Chill. This product maintains chilled temperatures for y hours with an ambient outside temperature of 20 degC.

The terminology 'frozen' refers to the duration of time that the product remains below -18 degC.

The terminology 'chilled' refers to the duration of time that the product remains between 0 and 8 degC.

The terminology 'product' means the material being transported. The Fridge e Wrap has been designed with the mail order market in mind.

Parameters affecting the performance of the Fridge e Wrap

The temperature profile is dependent on a number of factors. The most important parameters are, the average external ambient temperature and the physical properties of the product being tested. Consider the following:

External Temperature:

A Fridge e Wrap in a warm climate with a temperature of 30 degC compared to one in a colder climate with a temperature of 20 degC.

The product in the colder climate will remain below -18 degC (frozen) or between 0 and 8 degC (chilled) for longer than the same product in a warmer climate. In testing the bag, an average room temperature of approximately 20 degC is maintained.

Physical Properties for the Frozen Fridge e Wrap.

Most tests have been conducted using 'soft scoop ice cream'. The reason for this is that ice cream is the limiting factor. Other frozen goods, such as frozen water, frozen chicken tend to remain colder, for longer, than ice cream. Therefore, if ice cream remains below -18 degC for 20 hours, it is safe to assume that frozen meat or frozen water will remain below -18 degC for in excess of 20 hours.

Physical Properties for the Chilled Fridge e Wrap.

Most tests have been conducted using a mixture of chilled water and products generally found in the domestic fridge. The temperature probe is placed into a chilled tomato. The reason for this is that a tomato is easy to manipulate. It is a good representation of the products that would be transported in the Fridge e Wrap.

2.0 DESIGN PARAMETERS

A generic version of the Fridge e Wrap is represented pictorially in the attached photographs, Figure 1, 2, 3, and 4. The bags are made up of the following components:

2.1 Plastic and Insulation

The wrap is formed by multiple pieces of 6mm or 2.5mm polyethylene foam. The aim is to use multiple layers of insulation to systematically build up products that will perform a specific role. The tests performed to date are on:

6mm Fridge e Wrap Made from 1 piece of 6mm insulation.

18mm Fridge e Wrap Made from 3 pieces of 6mm insulation, layered.

30mm Fridge e Wrap Made from 5 pieces of 6mm insulation, layered.

It is intended to replace the 6mm foam with thinner, 2.5mm foam.

Layering the foam in this way has two main advantages. Layering appears to give improved thermal performance to, for example, one 30mm slab of foam. The other advantage is in production. It is easier, and faster to cut rolls of foam compared to slabs.

The wrap is made up of four pieces.

Top and Bottom.

A number of layers of foam are placed into a plastic sleeve. The plastic sleeve (or pouch bag) is specifically designed to be a reasonably close fit. The plastic sleeve is heat sealed closed. The top and bottom panels are identical.

Sides.

The four sides of the wrap are made up from two pieces, similar in design to the top and bottom. The side panels are designed to fit two sides of the outer box. As before, a number of layers of foam into a plastic sleeve. The sleeve is designed to be a close fit. The two side panels are heat sealed together at the ends.

To assemble the wrap, make up the cardboard box. Place the bottom section in first. This should fit tightly into the box. Then take the side panels and push them into place. The top panel is then placed on the top of the side panels.

2.2 Insulation

The insulation type used is closed cell polyethylene foam.

The thermal conductivity of this product is within the range of 0.04 and 0.055 W/mK.

The foam density is 30 kg/m³

The 'Fridge e Wrap Frozen/Chilled ', uses either 6mm or 2.5 mm thick Polyethylene foam. 2.4 Coolant

Fridge e Frozen Coolant

The Fridge e Frozen Coolant is an eutectic salt solution. The ratio of salt to water has been optimised. 0 37 kg of salt is used per litre of water. The salt used is sodium chloride.

This salt solution results in a eutectic mixture that undergoes a phase change at -21.4 degC. This is ideal for the transportation of many frozen food products.

Fridge e Chilled Coolant

The Fridge e Chilled Coolant used is domestic water from the tap. A small quantity of chloπne will be added to prevent the possibility of bacteπal growth in the water.

This water coolant undergoes a phase change at 0 degC. This is ideal for the transportation of chilled food products.

2.5 Cooling Elements

The Fridge e Frozen Coolant and Fridge e Chilled Coolant is contained inside plastic cooling elements. The cooling elements are provided pre-fϊlled. Each cooling element contains 1 litre of cooling solution. The cooling elements are 18cm wide and 30cm long. This size can be vaned depending on customer requirements.

The plastic is designed to operate at low temperature. It is 125 microns thick.

For added protection against puncture, the cooling element can be placed mside an outer pouch bag. The outer bag is designed to be a neat , tight fit and will be self sealing at one end.

3.0 The Bag Specification Summary

3.1 The Fridge e Wrap Dimensions

There are three sizes that have been designed and tested. However, the size is irrelevant. The idea of the system is that it is a flexible design which can be adjusted to meet the users specific needs. Different clients may need different sizes of box, different thickness of foam and different quantities of coolant. The methodology that will be used to satisfy these requirements will be by using the layeπng system described.

3.2 The Cooling Elements

The Fridge e Wrap Frozen uses a number of the Fridge e Frozen Coolant . The Fridge e Wrap Chill uses a number of the Fridge e Chilled Coolant.

Each one is as detailed in section 2.5

The cooling elements have the following dimensions: Length 30cm

Width 18cm (20cm with sealing edges)

Thickness 2cm (when frozen)

For maximum efficiency, it is imperative that the cooling elements are frozen flat, in a uniform smooth configuration.

It is also important to note that:

The Fridge e Frozen Coolant freezes at -21.4 degC. Therefore, the cooling elements must be placed flat in a freezer with an operating temperature lower than -22 degC.

The Fridge e Chilled Coolant freezes at 0 degC. Therefore, the cooling elements must be placed flat in a freezer with an operating temperature lower than 0 degC.

4.0 The Wrap Assembly

On receipt of the Fridge e Wrap.

4.1 Step 1

Freeze the cooling elements. The cooling elements (whether they contain Fridge e Frozen Coolant or Fridge e Chilled Coolant ) can be frozen in a domestic 3 or 4 star freeze. They must be frozen flat. They must also be frozen solid prior to use.

4.2 Step 2

When ready to use the Fridge e Wrap assemble the cardboard box. Tape down the bottom flaps of the cardboard.

4.3 Step 3

The wrap arrives flat packed. Open the 'Wrap' fully, place the bottom panel into the bottom of the box. Place the side panels into the box a push into place.

4.4 Step 3

For the Fridge e Wrap Frozen, place the required number of frozen cooling elements (each with Fridge e Frozen Coolant) onto the base of the Wrap. The tests so far, one product requires one, another requires two.

For the Fridge e Wrap Chilled, do the same as above (each with Fridge e Chilled Coolant).

4.5 Step 4

Place the product on top of the cooling elements, inside the Wrap.

4.6 Step 5 For the Fridge e Wrap Frozen, place some frozen cooling elements (each with Fridge e Frozen Coolant) around the sides and on top of the product. Again, the number required will vary.

For the Fridge e Wrap Chilled, do the same as above (each with Fridge e Chilled Coolant).

4.7 Step 6

Place the top panel onto the Fridge e Wrap, sealing the system closed.

4.8 Step 7

Seal the top of the cardboard box. 4.8 Step 8

The Fridge e Wrap is now ready to be delivered. 5.0 ATTACHMENTS

5.1 Attachments 1

Fridge e Wrap pictorial photographs (4 off)

5.2 Attachments 2

Graphical Test Data of the Fridge e Wrap Frozen and the Fridge e Wrap Chilled (1 of each)

5.3 Attachments 1

Fridge e Wrap Generic Drawing

Claims

The Claim

Claim 1: The Fridge E Wrap is a container that has an insulating layer of closed cell polyethylene foam made up of multiple layers of closed cell polyethylene sheet foam. These are arranged in three pieces: top, bottom and the four sides, which are heat-sealed together to form a wrap arrangement around anything placed in the container to keep it cool.

Claim 2: A container as claimed in claim 1 which keeps products frozen at below -18 Celsius by the use of salt-water filled bags (frozen cooling elements) with a composition of 0.37 kg salt per litre of water. The bags being frozen solid and then placed in the insulated container with the product to keep it frozen.

Claim 3 : A container as claimed in claim 1 which keeps products chilled at 1 to 8 Celsius by the use of water filled bags (chilled cooling elements). The bags are frozen solid and then placed in the container with the product to keep it chilled.