The function of Color Suns One-way degassing valve(coffee valve)

Can you understand what is means for the first picture? 
If you don't understand,it doesn't matter,I will explain to you.
The function of the one-way degassing valve.
1.It will help you release the carbon dioxide outside the coffee bags.After your coffee beans have been roasted,it will produce many carbon dioxide,the carbon dioxide need to be released outside the coffee bags: 1.The carbon dioxide full of your coffee bags that will cause the coffee bags explosion.2.The carbon dioxide in your coffee bags will make your coffee beans or coffee powder oxidation.
Our one-way degassing valve open pressure is : ≥2.3-5.5 mbar.(It means that when you carbon dioxide arrival 2.3-5.5mbar that our valve will begin to release the carbon dioxide outside the coffee bags)
The closed pressure is :≤2 mbar.(It means that when you carbon dioxide get to ≤2 mbar,our one-way degassing valve will stop releasing the carbon dioxide and keep the coffee aroma into your coffee bags.That is why you can smell the coffee aroma when you see some coffee with valves in the supper market,and the customer will check are the coffee fresh through smell the coffee aroma.)
2.Maybe you will worry the Oxygen get into the coffee bags that also can make the coffee beans or coffee powder oxidation.That is why the valve called one-way degassing valve.Our one-way degassing valve can prevent the Oxygen getting into the coffee bags.All of Color Suns one-way degassing valve will do the vacuum test to ensure the quality.
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If you have any question on the details,feel free to ask Miss Hebe.
Email: hebe@colorsuns.com 
Whatsapp: +86 13679820357
Skype: mai.hebe