- A vacuum flask (also known as a Dewar flask, Dewar bottle or thermos) is an insulating storage vessel that greatly lengthens the time over which its contents remain hotter or cooler than the flask's surroundings. Invented by Sir James Dewar in 1892, the vacuum flask consists of two flasks, placed one within the other and joined at the neck. The gap between the two flasks is partially evacuated of air, creating a near-vacuum which significantly reduces heat transfer by conduction or convection. The vacuum flask consists of two vessels, one placed within the other and joined at the neck. The gap between the two vessels is partially evacuated of air, creating a partial-vacuum which reduces heat conduction or convection. Heat transfer by thermal radiation may be minimized by silvering flask surfaces facing the gap but can become problematic if the flask's contents or surroundings are very hot; hence vacuum flasks usually hold contents below the boiling point of water. Most heat transfer occurs through the neck and opening of the flask, where there is no vacuum. Vacuum flasks are usually made of metal, borosilicate glass, foam or plastic and have their opening stoppered with cork or polyethylene plastic. Vacuum flasks are often used as insulated shipping containers. Extremely large or long vacuum flasks sometimes cannot fully support the inner flask from the neck alone, so additional support is provided by spacers between the interior and exterior shell. These spacers act as a thermal bridge and partially reduce the insulating properties of the flask around the area where the spacer contacts the interior surface. Several technological applications, such as NMR and MRI machines, rely on the use of double vacuum flasks. These flasks have two vacuum sections. The inner flask contains liquid helium and the outer flask contains liquid nitrogen, with one vacuum section in between. The loss of precious helium is limited in this way. Other improvements to the vacuum flask include the vapour-cooled radiation shield and the vapour-cooled neck, both of which help to reduce evaporation from the flask. A sports bottle is a water tool for outdoor sports. Compared with other water tools, a sports bottle has the characteristics of durability, safety, reliability, convenience and insurance. Sport water bottle has become a relatively popular and environmentally friendly new sports product. With the rise, development and continuous growth of domestic outdoor sports, the sales volume of sports water bottle in China is expanding year by year. According to its function, sports water bottle can be divided into 1. Sports water bottle with filter function: Portable water bottle is a new sports water bottle that has appeared in the past two years. Different fresh water such as river water, stream water and tap water can be quickly filtered into direct drinking water, which is convenient for obtaining safe and secure drinking water anytime and anywhere under outdoor sports conditions; 2. Ordinary sports water bottle: traditional sports water equipment can only store drinking water needed for sports; 3. Folding sports water bottle: portable folding water bottle, the bottle body can be folded after the water is dry, and it does not take up space. According to its application, sports water bottle can be divided into 1. Sports use It refers to the water bottle used for some relatively intense sports, such as running, mountain climbing, etc. It is characterized by more emphasis on the quality and sealing function of the buckle; 2. Outdoor use refers to the use of hiking, picnic, tourism and other occasions. It is characterized by more lightweight and multiple forms of hanging buckles; 3. It can be said that the water bottle used by students is similar to the outdoor water bottle, but because it is used by children, it is different from the professional water bottle in design and production. The sports water bottle used by students is more convenient and easy to use, such as It can be used to open the cap by rotating instead of opening the cap with a plug. A mug is a type of cup typically used for drinking hot drinks, such as coffee, hot chocolate, or tea. Mugs usually have handles and hold a larger amount of fluid than other types of cup. Travel mugs (introduced in the 1980s) generally employ thermal insulation properties for transporting hot or cold liquids. Similar to a vacuum flask, a travel mug is usually well-insulated and completely enclosed to prevent spillage or leaking, but will generally have an opening in the cover through which the contents can be consumed during transportation without spillage. As the primary mechanism by which hot (not warm) beverages lose heat is evaporation, a lid serves a vital role in keeping the drink hot; even a thin plastic one which conducts heat quite quickly. Mugs with inner and outer walls, but not vacuum treated, are generally called double wall mugs. Usually stainless steel will be used for the inner wall while outer wall can be stainless steel, plastic, or even embedded with other materials. A water bottle is a container that is used to hold water, liquids or other beverages for consumption. The use of a water bottle allows an individual to drink and transport a beverage from one place to another. A water bottle is usually made of plastic, glass, or metal. Metal water bottles are preferable as the material is better for water bottles as they allow the liquid to stay colder or warmer for longer periods of time in different temperature environment conditions and are usually more durable than plastic and or glass. Water bottles are available in different shapes, colors, and sizes. In the past, water bottles were sometimes made of wood, bark, or animal skins such as leather, hide and sheepskin. Water bottles can be either disposable or reusable. Reusable water bottles can also be used for liquids such as juice, iced tea, alcoholic beverages, or soft drinks. Reusable water bottles reduce plastic waste and contribute to saving the environment. Easily portable, water bottles make for convenient use. Non-reusable water bottles often list nutrition facts. Glass water bottles are heavier than plastic, stainless steel, or aluminium, and are easier to damage or completely break. Like metal, they also have a high level of temperature transfer, so they are not ideal for very hot or cold liquids. Some types of vacuum-insulated flasks use an inner layer of glass (which is easy to clean), and an outer layer of metal or plastic which helps shield the glass from breakage. Such bottles may still break if dropped, and thus some brands are triple-layer, with the glass inside two layers of plastic; this is a common configuration for large flasks intended for coffee or other liquids that need to be insulated. Stainless steel water bottles are growing in popularity, they are durable, and their previous contents retain less odor and taste than most plastic bottles, but can sometimes develop a metallic taste. Therefore, stainless steel bottles often contain resin or epoxy liners to protect the contents from taste and odor transfer or corrosion. Although most liners today are BPA-free, older and less expensive models can contain BPA and can also use glass liners. Metal (especially steel) water bottles can be heavier than their plastic counterparts. Single-walled metal bottles readily transfer temperature of contents to external surfaces, which makes them unsuitable for use with unusually hot or cold liquids. Double-walled metal bottles are insulated to keep cold liquids cold and hot liquids hot, without the external surface being too hot or too cold. Because double-walled bottles have more metal in them, they are more expensive. They are typically vacuum-insulated, but some may have a solid or gel insulation between the metal walls. In addition, it also includes kids water bottle, smart water bottle, etc.
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