Type
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Thermos. Thermoses of a classic design: rather narrow and tall cylindrical vessels with a small diameter of the neck. They are intended mainly for a relatively pure liquid without impurities or with a minimum of impurities — tea, coffee, etc. Such vessels can be hermetically sealed, making them convenient for long hikes and trips. The average capacity of a classic thermos is from 500 to 1000 mL, but in general the range of such models is quite diverse.
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Thermos jug. A type of thermos designed mainly for home use and not intended for travel use. Distinctive features of such models are, firstly, rather large volumes (usually from a liter or more), and secondly, a spout for easy pouring of contents. Also note that it is among the jugs that the pump for liquid is most often found (see "Opening / serving"), in other types of thermoses such a device is practically not used. A thermos jug can be useful, for example, for storing a supply of hot water for tea parties during the day.
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Mug-thermos. Mugs with reinforced thermal insulation that allows you to keep the temperature of the drink for a long time. However, such vessels are designed primarily for ease of use “on the go”, and not for long-term storage of the contents (this is how thermo mugs differ from the thermos flasks described below). The design of thermo mugs often provides for valves or drinker
...lids (see "Opening / serving") that allow you to drink without opening the lid. Models with twist-on lids are somewhat less common — they retain heat more reliably when closed, but lose it faster when drinking. The capacity of all thermos mugs, of course, is small — usually up to half a liter.
— Thermos flask. Relatively small thermoses, shaped like "sports" bottles or camping flasks for water. The key difference between such models and conventional thermoses is that the contents of the flask can be drunk directly from the vessel without pouring it into a separate container (whereas it is difficult with a classic thermos, it is better to use a cup with it). At the same time, flasks are better suited for long-term storage of drinks than thermos mugs (see above), they can be used not only for drinking on the go, but also for transporting drinks on a long journey.
— Food thermos. Thermoses designed for hot food — soups, cereals, etc. A distinctive feature of such vessels is a wide neck through which not only liquid, but also rather large pieces of solid food can freely pass. In addition, the large neck width makes it easy to clean after use. And some models even come with containers for added convenience (see below). The volume of a food thermos can be up to several liters, although there are options for 400 – 500 mL.
— Children's thermos. Thermoses intended for children differ from "adult" models mainly in their reduced size and characteristic bright design. In terms of functionality, most of these models correspond to classic thermoses, however, there are other options — in particular, thermoses-flasks and food containers (for more details, see above).
— Automug. Specialized thermos mugs designed for use in a car. The key difference between such dishes and ordinary thermos mugs (see above) is the presence of a heating system powered by a car cigarette lighter. Auto mugs can be very useful on long journeys on roads where there are rarely cafes, gas stations and other places where you can get tea or coffee.Capacity
The nominal volume of a thermos is the maximum amount of contents that it can be guaranteed to contain.
This parameter is directly related to the type (see above). So, a capacity
of up to 500 mL is quite normal for a thermo mug, a flask or a baby thermos, but it is considered small for a classic thermos, and even more so a jug or a thermos for food. The
"500 to 1000 mL" category includes most traditional and food models; for mugs, flasks and children's thermoses, this is actually the maximum volume. Among the jugs there are many more capacious options —
from 1000 to 1500 mL. A volume
of 1500 to 2000 mL is considered quite large, and the most solid models can hold
more than 2 liters.
Anyway, a large volume allows you to hold more drink or food, but the downside of this is an increase in the size, weight and price of the thermos itself. Therefore, when choosing, you should not chase the maximum capacity, but proceed from real needs. For example, a model of 400 – 500 mL is quite enough for two cups of coffee, and for tea drinking at a halt for 3 – 4 people, it is advisable to have a model of at least 1000 mL. More detailed selection recommendations can be found in special sources; especially they will be useful to those who choose a thermos for long-distance hiking trips.
Opening/supply
The type of main cover provided in a thermos. The main cover in this case is a device that directly covers the working volume of the vessel; an additional cap can be installed on top of it, which often also plays the role of a cup. In modern thermoses there are the following types of main lids:
screw-on (screw),
valve,
cover,
hinged cover,
drinking cover,
pump (pump),
stopper. Here are the features of each of them.
- Screws on (screw). Solid (without holes) screw-on cover, secured with a thread. Such lids are very simple and at the same time reliable, but you cannot drink or drain the contents through the classic screw - you have to remove it completely. There is also a more advanced design that allows you to drain the contents without removing the screw - just partially unscrew it; however, this is a rather specific option that is not used often. Be that as it may, twists are found mainly among classic and food thermoses (see “Type”), for which the mentioned nuances are not decisive.
- Valve. A cover (most often threaded) equipped with a valve through which the liquid contents of the thermos can freely flow. Such lids are more complex and more expensive than “blind” screws (see above), but to access the contents you d
...on’t need to unscrew the screw every time, just open the valve. This not only provides additional convenience, but also reduces heat loss. Thanks to these advantages, valves are extremely popular in classic thermos flasks; they are also often used in thermal mugs (see “Type”). The disadvantages of this option include the fact that the valve opening is usually made quite narrow and is easily clogged with impurities (for example, tea leaves or coffee grounds). Therefore, the valve can only be used for liquids without such impurities (this also applies to food thermoses, which can also be equipped with valves). However, there are models with two different valves included, for drinks of different consistencies and aromas.
- Lid. Lids in this case are devices that do not have threads (unlike the screws described above) and are held in place solely by friction or a latch. The design of the lids can be different: some cover the neck from the outside, others are pressed inward when closing; There are also more specific options. In any case, the lids are easy to remove and put back on, but they are not very reliable - for example, it is not recommended to turn such vessels over. Therefore, this option is found mainly in thermal mugs and thermoses for food (see “Type”), for which the mentioned disadvantages are not critical.
— Hinged cover. A variation of the lids described above, which, when opened, is not removed entirely, but is folded to the side on a special mount. Thanks to this, the likelihood of loss is reduced: in fact, you can only lose the cover along with the thermos itself; and a latch, spring, or other similar device is usually provided to hold the cover in the open position. On the other hand, mount somewhat affects the price and dimensions of the vessel. This drawback is least critical for flasks and mugs (see “Type”), and it is among these types that hinged lids are most often found.
— Cover-drinker. Lid (regular or threaded), complemented by a special hole for drinking. This design allows you to drink from the vessel without removing the cover; and during “non-working” hours the hole is covered with a flap or other similar device. Drinking lids are extremely popular in thermal mugs and auto mugs (see “Type”): they allow you to drink from the mug comfortably while at the same time minimizing heat loss and the likelihood of spilling the contents.
— Pump (pump). Lid (classic or threaded) with built-in pump. Most often, this pump is activated by a special button: when you press this button, a portion of liquid comes out of the spout, and the thermos does not need to be tilted. However, such devices are quite complex and cumbersome, so it makes sense to use them only in thermos jugs (see “Type”): the size and weight of the pump is small compared to the dimensions of the jug itself, and tilting such a thermos can be difficult - it’s easier to use a pump.
- Cork. A classic stopper that fits tightly into the neck of a thermos and is held in it without threads or other similar devices. Corks differ from the lids described above in their greater thickness, and also in that they are inserted into the neck from the inside (while the cover can cover the vessel from the outside). Plugs are very easy to use, but have low reliability, which decreases even more as they wear out. As a result, this option has practically fallen out of use.Flask material
The material from which the flask is made is the inner container of the thermos, which usually comes into direct contact with the product inside. Among the most popular modern materials are
stainless steel,
glass,
plastic and ceramics; here are their main features:
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— Glass. The main advantage of glass over stainless steel is complete chemical inertness: such flasks do not oxidize and do not acquire an unpleasant odour over time. This makes them perfect for products where flavor matters a lot, such as herbal blends. In addition, this material retains heat better. On the other hand, the strength of glass is significantly lower, and such thermoses are...rather poorly suited for hiking — mostly glass flasks are placed in models that are not designed for difficult conditions.
— Plastic. This material is characterized by low cost and relatively low thermal conductivity (which helps to retain heat). On the other hand, the plastic surface does not tolerate prolonged contact with hot liquids: it can release unpleasant odours or even harmful substances. Thus, plastic flasks are relatively rare — mainly in thermos mugs, which, by definition, are not designed for long-term storage of hot drinks, as well as in inexpensive food thermoses.
— Ceramics. A material that is in many ways similar to glass: ceramics do not react with the contents of a thermos, do not affect its taste and smell, but are afraid of strong blows. At the same time, the reliability of this material is somewhat higher than that of glass — on the other hand, ceramics are more expensive. Therefore, this option has not received much distribution.Material
The material from which the body is made is the outer part of the thermos, inside of which the flask is placed.
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Plastic. One of the main advantages of this material is its low cost. In addition, it can be given any colour, and low thermal conductivity contributes to better temperature retention. On the other hand, plastic cases are noticeably inferior to steel cases in terms of strength and reliability, and scratches easily appear on their surface, due to which the product loses its presentation as it wears out. Therefore, plastic is used mainly in inexpensive models of thermoses.
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Stainless steel. Steel is somewhat more expensive than plastic, but much stronger and more reliable. In addition, the steel surface has a stylish appearance that is long-lasting thanks to its scratch resistance. Among the shortcomings of this material, in addition to the price, high thermal conductivity can be noted; manufacturers usually compensate for this moment with various tricks that further increase the price. Nevertheless, in general, steel is a very favorable material in terms of price and quality, and it is from it that the cases in most modern thermoses are made.
Additional cup / bowl
This feature means that the thermos is equipped with
two cups or bowls at once (depending on the type, see above).
Many modern thermoses are equipped with a drinking cup or a food bowl; in the stowed position, such a container usually plays the role of a lid. In some models of cups / bowls, there can be two at once, which is useful if the thermos is used not only for yourself: you do not have to carry additional dishes with you separately.
