There are no other ways to keep food fresh on the road or for a walk, except for putting them in a special insulated bag. What is a thermo bag and how to choose a cooler bag?

Portable cooler bags are, strictly speaking, not quite the right name. You can apply it only to the automotive cooling device, powered by a battery and having a cooling system. These mini-fridges deserve a separate article. For that, which will be discussed, the name thermo bag, thermal container, or insulated bag is more suitable. The cold inside the tank is not produced, but only remains. Actually, like heat, if you put hot foods there.

customers As bag-reader.

Have you seen how a typical thermos bulb works? Heat insulating body, and inside the flask of reflective material. Bag cooler is arranged almost the same principle. It consists of thick walls, inside of which is a layer of thermally insulating foam. Placed inside the products are separated from the environment by a layer that conducts heat poorly, heat exchange occurs slowly, due to which the initial temperature is maintained longer.

Hot products can be additionally wrapped, and special cold batteries are placed in cooler bags to maintain low temperature. With batteries, the cooler bag saves food for much longer.

But the rate of temperature change is not constant and depends on several factors. They must be taken into account first of all when you choose a cooler bag in a store.

Main selection criteria

Volume

The larger the volume of the cooler bag, the slower the temperature inside it changes. But volume is determined by your needs. If you go on a long picnic by a large company, you can choose roomy cooler bags, and for a student to preserve the freshness of a pair of sandwiches, a miniature sandwich maker and lunch box are enough. The smallest cooler bag weighs only 300-400 g and holds 2-3 sandwiches.

The number of cold accumulators depends on the volume of products. Usually they come bundled with the bag, but you can also buy them separately.

Materials and Construction

In the store you can see a variety of options for thermo bags and thermal containers. They differ simply: the container is made of hard plastic, and the bag is made of more or less soft materials. The container always keeps its shape, you can even sit on a large thermal container. Cooler bags are softer, their shape depends on the wall thickness and the presence of the frame.

The walls of the container are usually thicker and it maintains the temperature better. The thermal insulation properties of the bag depend on the thickness of the walls and the quality of the thermally insulating material. Do not pay attention to the cooler bags with a wall thickness of less than 0.8 cm. They can keep the cold no more than 2-3 hours, and even at a low outside temperature.

If you live in a region where there is a strong heat in summer, then choose the right cooler bag with thicker walls.

It is believed that a thermal container with a nominal load and using the recommended amount of cold accumulators can maintain the temperature 25 ° lower than the environment. Cooler bag provides a temperature of just 15 ° below.

The outer layer of the bag is made of durable synthetic fabric or film, easy to clean and quick-drying. It is better if the material is water repellent.

The inner layer must be made of foil material with reflective properties. A cooler bag with simple plastic or oilcloth inside keeps the cold much worse, even with cold batteries. The inner layer must be waterproof and the joints must be airtight.

Pay attention to such small detail as the presence of fasteners for battery plates. This little thing is noticeable on how convenient it will be to use the refrigerator.

Small bags should have comfortable carrying handles and a wide shoulder strap. Cooler bags of more impressive volume can be made in the form of a backpack, it is convenient for hiking. The most dimensional and capacious cooler bags and thermal containers are equipped with a convenient telescopic handle and mounted on a frame with wheels, like a modern suitcase.

Cold Storage Batteries

Usually they look like a flat rectangular plastic flask. Batteries can be different in size and volume, in shape and filler. Rather, the filler is one - carboxymethylcellulose, but in a different aggregative state. The filler may be in the form of a solution or gel. Gel batteries heat up more slowly, but they are more expensive. Before using the battery must be kept in the freezer for at least 10-12 hours.

The shape of the batteries is usually rectangular, but there may be differences in volume and surface area. There are also batteries with notches for a better fit to the walls of the bottles. On the surface is usually indicated on how much is calculated one battery. How much is required depends on the volume of the bag.

It is not necessary to replace the solution inside. The number of freeze-thaw cycles is limited only by the strength of the body. Until it cracks and starts leaking, the battery is fine.

Other Parameters of

Many cooler bags are equipped with additional components: a set of campware, bottle holders, pockets, etc. The quality of temperature preservation does not affect all this, but significantly increases the cost.

The presence of special locks on large-capacity bags protects the bag from sudden opening and prevents products from falling out, even if the bag falls.

A couple of tips for buyers of

• . If you bought an inexpensive cooler bag, inside which does not have a foil reflective layer, you can add it yourself by using thermal insulation material from a hardware store.
• You can replace cold accumulators with available tools: pour saline solution into plastic bottles or into tetrapack bags and freeze them.