Development History of Vacuum Flask

Early Thermos Flasks
A double-walled container ever excavated in the Roman Pompeii city is ruined, this container possibly is the predecessor of the vacuum flask, however in fact it is called "the world's first truly thermos Dewar". In 1643, Italian scientist Evangelista Torricelli built a mercury barometer famous vacuum theory. The emergence of this theory thermos really is of great significance, but in the two-and-a-half centuries later, he did not invent the real vacuum flask. In 1879, German physicist Tile for the liquefied gas storage laboratory, he listened to the recommendations of Professor Lide, then used the two middle vacuum thin glasses to make container. He was the author of the papers "Varinholid bottle" in 1881. In 1890, British chemist Shield Williams improved the Varinholid bottles, coated with a layer of silver on the sidewall, which can reduce the heat radiation, slowing the dissipation of heat through the glass,finally the thermos bottle was born.

James Dewar

Modern Thermos Vacuum Bottle
The inventor of modern vacuum thermos bottle is James Dewar, he is a scientist in the Scotland, studied the very low temperature of liquid. In 1892, Dewar was invited to the British Science Institute will research the "liquefied" courses. In order to better teaching, he produced a double-layer glass container, and two layers of bladder wall painted with mercury, greatly reduced heat transfer. Then he deprived the air between the two layers, so the vacuum bottle created and only vacuum bottle is the world's first vacuum flask. The thermos is called Dewar. London Institute holds early Dewar vacuum products. Dewar did not attach importance to the invention of the vacuum bottle, but great importance to the theory of extraction air, and applied for a patent for this theory. In 1902, German Berg saw a huge potential market of thermos bottle , began to sell the thermos, and fought on own the behalf of thermos patent two years. He found the glass inner easily fragmented, so produced with nickel shell to protect the bottles bladder. In the beginning, the thermos bottle is mostly used in laboratories, hospitals and expedition, and later gradually moved into people's daily lives.


Thermos Flask Post Modern Development
In 1904, the Berlin blown glassware worker Boolean added a retaining heat sets to long thermos bottles , so the market would have a storage container of hot coffee or tea. Since then, a variety of thermos flask would come out one after another. It was found that the thermal effects of the thermos bottle stopper are the worst part of the bottle. Later, people used inflated rubber, cork, plastic plugs to replace and improve the insulation effect.



China Huayoung Industry Co.,Ltd. - Started producing vacuum flask, travel mug, beverage bottle and thermos from 2004, the manufacturer you can trust!
Website:  http://www.vacuumflasks-travelmugs.com/

How to Buy a Good Travel Mug

Here are five steps to consider before we buy a travel mug with better value and keep our drink hot for longer time.

Travel Mug - China Huayoung

Steps

1. Buy a double-wall vacuum stainless-steel travel mug(or vacuum flask). Although stainless-steel at the beginning costs more, that will give yo much better value for our money. You can expect excellent performance from a stainless-steel travel mug, keeping your water hot for an hour at least.

2. Buy a plastic travel mug, with a stainless steel liner. Plastic liners long time will absorb coffee or tea, making your drink taste so bad. It also breaks easily when dropped.

3. Make sure the size of the travel mug fit the cup holder that is in your car or truck. If you don't have a cup holder or don't like to use one, look for a travel mug with a wide non-slip bottom.

4. Choose a tight lid. The lids that snap on can sometimes come off if the travel mug tips over or is dropped. Screw on lids are better because they stay on no matter what happens and that's the idea of a travel mug to start with.

5. Capacity matters. If you only drink a small amount, consider to find a smaller 8 oz. travel mug because it's easier to handle. On the other hand, if you want a large amount of coffee or tea to drink, consider a larger 16 or 20 oz. travel mug.

Tips

• If we leave our travel mug in the car while at work, put it away from direct sunlight. Hot sun magnified by the windows will damage the rubber seals in the lid.

• Hand wash your travel mug instead of putting it in the dishwasher. Sometimes soap residue gets left behind either in the lid or on the walls of the travel mug and no one likes that kind of surprise. Be sure to rinse it extra well, so all that you taste is the rich flavor of your coffee or tea.

• Travel mugs with silicon rubber components tend to flavour the brew.

What's the Vacuum Flask ?

Vacuum Flask-China Huayoung

A vacuum flask (also known as a Dewar flask, Dewar bottle, Beverage 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 prevents heat transfer by conduction or convection.

Vacuum flasks are used domestically to keep beverages hot or cold for extended periods of time and for many purposes in industry.

Welcome to our website: www.vacuumflasks-travelmugs.com

How Vacuum Flasks, Travel Mugs and Thermos Work?

Vacuum Flask

Most of us have or know the vacuum flask. I could remember to be a child having one that came with my lunch box. One day my mother may put apple juice in it and at lunch I would have nice, cold apple juice. The another day she would put hot creamy corn soup in it and I would have hot tomato soup for lunch. And I could remember asking, "How does it know whether to keep stuff heat or cool?" Where's the transition, in other words... Or, similarly, "You heat stuff up in an oven and cool them down in a fridge -- how come this thing can do both?" In this edition of How It Works, you can learn how a vacuum flask knows" what to do.


Heat Transfer
We take a glass of cold apple juice or a bowl of hot creamy corn soup and let them sit out on the kitchen table. Guess what will happen: The bowl of soup will cool down to kitchen temperature, and the glass of apple juice will warm up to kitchen temperature. It is a thermodynamic truth of life -- if we put any two things with different temperatures together, then heat transfer will let them to get to the same temperature. So a "kitchen" and a "hot bowl of creamy corn soup" get to the same temperature by the heat transfer process -- the kitchen has a bit warmer , the bowl of soup has a lot cooler.

If we wanna keep a bowl of creamy corn soup hot as long as possible -- that's if we wanna reduce the natural heat transfer process as much as we can -- we have to slow down the three processes that cause heat transfer. The processes are:

• Conduction - Let's begin a simple question: What's heat? Heat is atomic motion. 

The very best case for this phenomenon would be to take a metal stick and heat one end of it. The other end will get warmer and then hot through conduction. When you put a metal bar on the fireplace the inside of the bar gets hot through conduction of the heat through the metal in the bottom of the bar. Some thing (namely metals) are better heat conductors than others (for example, wood). 

• Radiation - Our eyes can not see infrared, but our skin can feel it. 

• Convection - Convection is a property of liquids and gases. It occurs because when a liquid or gas gets hot, it tends to rise above the rest of the body of liquid or gas. So, if you have a hot bowl of soup on the table, it heats a layer of air surrounding the bowl. That layer then rises because it is hotter than the surrounding air. Cold air fills in the space left by the rising hot air. This new cold air then heats up and rises, and the cycle repeats. It is possible to speed up convection -- that is why you blow on hot soup to cool it down. If it weren't for convection your soup would stay hot a lot longer, because it turns out that air is a pretty poor heat conductor.

We can see all three heat transfer processes occurring when we stand beside a bonfir:

We possibly should stand at least 15 feet away from a big bonfire like this one. What keeps you away is heat radiating from the fire through infrared radiation. The flames and smoke are carried upward by convection: Air around the fire heats up and rises. The place 3 feet beneath the fire will get hot, heated by conduction. The top layer of soil is directly heated (by radiation), and then the heat is conducted through layers of dirt deep into the ground.

To make a good vacuum flask or travel mug, what you wanna do is reduce these three heat transfer as much as you can.


 Workings of a inner vacuum flask 

One method to make a vacuum flask or travel mug - like container would be to take a beverage bottle and wrap it in, such as, foam. Insulation works by two basic principles. First, the plastic in the foam is not a good heat conductor. Second, the air trapped in the foam is an even worse heat conductor. Accordingly conduction has been slow down. Due to the air is broken into tiny bubbles, the other thing foam does is largely reduce convection inside the foam. Heat transfer through foam is as a result pretty small. 

Apparently , there is a much better insulator than foam: a vacuum. A vacuum has very few atoms. A "absolute vacuum" has zero atoms. It is almost impossible to make a perfect vacuum, but we can get close to it. Without atoms we reduce conduction and convection completely.

What you find in a vacuum flask or travel mug is a glass envelope holding a vacuum. Inside is glass, and out of the glass is a vacuum. The glass envelope is easily fragile, so it's encased in a plastic or metal case. In many vacuum flasks or travel mugs we could actually unscrew and take this glass envelope out. 

A vacuum flask then goes one next step. The glass is silvered (like a mirror) to cut down infra-red radiation. The group of a vacuum and the silvering greatly reduces heat transfer by convection, conduction and radiation.

So why do hot soup in a thermos ever cold down? You can find in the figure two paths for heat transfer. The big one is the cap. The other is the glass, which provides a conduction path on top of the vacuum flask where the inner and outer walls meet. Even though heat transfer through these paths is small, it is not zero.

Does the vacuum flask recognize whether the fluid inside it is hot or cold? No. All the thermos is doing is limiting heat transfer with the walls of the thermos. That lets the fluid inside keep its temperature nearly steady for a long time (whatever the temperature is hot or cold).

China Huayoung Industry Co.,Ltd. - Started producing vacuum flask, travel mug, beverage bottle and thermos from 2004, the manufacturer you can trust.

Website: http://www.vacuumflasks-travelmugs.com