A thermos (also known as a thermal flask, vacuum flask or thermos water bottle) is a long concealed flask that insulates liquids for a very long time. Unlike other water bottles, a thermos is composed of two flasks placed one inside the other that joins at the neck of the flask which reduces heat transfer significantly. Therefore, thermoses are great for keeping hot beverages warm and cold beverages cool for a long time. It's important to consider the material of your thermos if you plan on ordering a large quantity of thermoses as a corporate gift. Thermoses are the perfect corporate gift to consider to give to potential clients and customers. A durable resilient thermos corporate gift can leave a long lasting impression on your colleagues thus promoting your business brand.
Materials
Thermos flasks are made up of a variety of materials including stainless steel, aluminium, plastic, and glass. Each material has a different effectiveness on reducing heat transfer emitted from the thermal flask. Below the types of metals and materials used will be explored
Stainless Steel
One of the most common materials found in thermos flasks is stainless steel. It's resistant to corrosion and it's very resilient. It's a cheap and widely available material which is suited for producing large quantities of thermoses. Most Thermos products are manufactured using 304 Stainless steel (also referred to as 18/10 or 18/8 stainless steel) and are composed of 8-10% Nickel and 18-20% Chromium. Stainless steel can maintain the required temperature of a liquid for a long period of time. Hot beverages can be kept hot for 6 hours while cold beverages can be kept cool for 24 hours. Polished stainless metals will only lose less than 10% of heat to irradiative heat transfer. Stainless steel is also sanitary and anti bacterial hence it's also used in thermos soup pots for storing food. They do not leak water and there is no concern for linings to disintegrate. due to stainless steel not needing an inner coating.
Austenitic stainless steel
Austentic stainless steel are a form of stainless steel that contains a significant amount of chromium and nickel as well as some iron. It's crystalline structure is austenite and it prevents steel from being hardened by heat thus making them non magnetic. The 300 series stainless steel achieve their structure by the addition of nickel. Therefore, when we buy thermos mugs or cutlery or stainless steel cutlery, we will see numbers marked on the product like 304 Stainless steel, 316 Stainless steel, etc. 304 Stainless Steel and 316 Stainless Steel are internationally approved food grade stainless steels. They have good corrosion resistance and heat resistance hence they are commonly used in cutlery, tableware, water bottles and thermos flasks. The molybdenum content of 316 Stainless Steel is 2% higher than 304 Stainless steel. Therefore, selecting a 316 Stainless steel thermos flask is preferred if you are in a strenuous harsh environment. A corporate gift made of 316 stainless steel is the best quality material to give to your customers.
Aluminium
Aluminium is also a common material used for manufacturing thermos mugs and thermos bottles. Anodized aluminium is a light material and also cheap to produce. Like, stainless steel, Anodized aluminium is corrosion resistant and durable. Aluminium is also a light metal hence it's less heavy than stainless steel water bottles. Generally, an aluminium thermos is best suited for casual and less strenuous outdoor activities. Aluminium water bottles are generally more stylish in appearance unlike stainless steel water bottles. However, aluminium is more likely to react to certain liquids therefore it's required for them to come with a protective lining the prevent the bottle to mix with the liquid inside. Therefore, it's important to only consider aluminium thermos bottles that are lined with BPA free epoxy resins.
Plastic
Most thermal flasks and water bottles are made up of stainless steel, multiple layers of plastic are incorporated into their design. The addition of plastic further reduces the lower thermal conductivity thus preventing heat loss. However, plastic is not used within the flask and is used to line the outside of the flask and the lining on the thermos cup cover. All thermos plastic products are food grade safe materials and are BPA free (Bisphenol A). The plastic coat on a stainless steel thermos provides more colours and design as opposed to a stainless steel surfaced bottles. Plastic thermos bottles are great for customising new designs and making corporate gifts.
Glass
Inside a thermos is a glass envelope holding the vacuum. This glass in wrapped in a plastic or metal case and is coated with silver to decrease infrared radiation. Silvered glass and the thermos vacuum are large factors in reducing heat transfer by convection, conduction and radiation. However, one explanation to why heat eventually gets lost from the thermos is because heat actually gets lost through the glass which provides a conduction path where the inner and outer walls meet at the top of the flask. This heat loss is not very significant but it is one of the explanations as to how hot liquids inside a thermos eventually cools down. The other major reason for heat loss is through the cap of the thermos.
Best Material
Metals like aluminium and stainless steel are the best for preventing heat transfer. Of the three modes of heat transfer (convection, conduction and radiation) only the design of the vacuum chamber in the thermos flask is efficient at preventing just convection and conduction. However, radiation, can easily move through the vacuum. Unlike plastic, metals like stainless steel and aluminium are effective at reducing heat transfer from radiation. Between stainless steel water bottles and aluminium water bottles, aluminium is more suited for less strenuous activity is better in appearance. However overall, the most durable and best thermos is the 316 Stainless Steel Thermos flask as it is the most corrosion and temperature resistant. Therefore, when preparing a thermos corporate gift order, it's best recommended to select the 316 stainless steel material. This resilient material will be the perfect corporate gift for your customers to highlight your company brand.
FAQ
Heat is lost through the glass envelope in the flask by conduction, and heat is also lost through the plastic cap.
The best thermos material is 316 stainless steel.
They are internationally approved food grade stainless steels. They have good corrosion resistance and heat resistance.
Graduated with a Masters degree from Ireland with a Masters degree in Business Information system. English native speaker specialising in business and data analyst. Currently enrolled in Tunghai University's language centre for studying Mandarin Chinese and undertaking a student marketing internship at SourceEC. My role involves content writing, SEO analysis and web page optimisation After my studies and completion of this internship, I am hoping to pursue a career in data analytics in the digital marketing field in Asia.
