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The secret behind vacuum flask parts and functions

October 2nd, 2023

Nowadays, a vacuum flask has become our reliable companion at work, going out for exercise or travel as it retains our favorite drink's taste and temperature for extended hours. The secret lies with the vacuum flask parts and functions. Several parts of a vacuum flask such as the screw-on stopper, vacuum, the refill, etc, each part has its own function.

Screw-on stopper

This part is normally made from silicone, which fully covers the mouth of the vacuum flask to lock the heat inside. To avoid the heat escape from the bottle when opening the gasket, several screw-on stoppers are created with a press button. Once pressed, it will open a small space enough to pour out the water, the user will not need to twist open the stopper.

The case: plastic or stainless steel

Rang Dong has just marketed a series of vacuum flasks for individual use.

Manufacturers have spent a lot of time in the design of the vacuum flask's outer case in order to make it eye-catching. Artworks to decorate the case may come from cartoon characters to serve kids and teenagers, while a minimalist design that creates a sporty feeling matches well with adult users' taste.

The refill: silver-coated glass or double-wall stainless steel

The flask refill is made of two-layer glass or stainless steel, with a vacuum layer in between the inner and the outer layers. 

In comparison, stainless steel makes the flask lighter and smaller than that using glass refill, while the glass refill keeps the heat longer and retains the drink taste better thanks to its coated reflective metal layer. However, the glass refill is fragile, it can be broken if dropped from 10 centimeters (4 inches) high, while the stainless steel refill is tough and easy to bring along when traveling.


A vacuum between the layers of the glass/stainless steel refill helps prevent heat conduction and radiation.

Since vacuum does not conduct heat, the temperature of the beverage in storage is retained for a long time. Vacuum is the most important part of a flask.

Refill support

Normally, three pads are placed between the two inner jars to fix the refill position. Looking from outside, we can see three black points around the bottom, but they don't directly contact the liquid, therefore they cause no harm to the user's health.

The flask base

The flask base is often made of TPE plastic to keep the flask stand stable and insulate well with the table surface.

By this point, we've discovered the secret behind all of the vacuum flask parts and functions. Thanks to these advantages, the item has been made widely available by Rang Dong, Vietnam's leading manufacturer of vacuum flask products.

Should you have any questions, wish to share your ideas about vacuum flasks or request a quotation, please send us an email to: export@rangdong.com.vn.

Our website: vacuumflask.rangdong.com.vn

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