Is glass tableware safe? How to use glass tableware correctly?
For office workers, glass tableware is not easy to change color and produce peculiar smell due to long-term heating, which has become the choice of more meal takers. However, there are also reports of explosion due to improper use, heating or collision from time to time. Glass products have different materials and production processes, and the scope of use is also different. Correct understanding and use of glass tableware will be safer.
Heat resistant glass withstands sudden cold and hot changes
The common glass on the market can be roughly divided into three categories: ordinary glass, tempered glass and heat-resistant glass. The common glass is mainly composed of sodium and calcium, and has no special properties. It is often used in early doors and windows. Its biggest advantage lies in its low cost and low price. Toughened glass refers to the chemical or physical secondary tempering treatment on the basis of ordinary glass, and its hardness is higher than that of ordinary glass. It is widely used in indoor glass partition, outdoor glass curtain wall and automobile windshield glass. Heat resistant glass is the most widely used in tableware and kitchenware. It is based on ordinary glass, adding boric acid and silicic acid with strong heat resistance, and can withstand rapid temperature difference changes. It is also called borosilicate heat-resistant glass because it is made of borosilicate.
Taking the glass products of its company as an example, its operating temperature range is - 20 ℃ - 400 ℃ theoretically, and it can withstand the sudden change of temperature difference between 120 ℃ and 150 ℃. This concept can be understood as: glass ware is directly put into boiling water (boiling water temperature is 100 ℃ under standard atmospheric pressure) after it is taken out of the refrigerator freezer (the temperature of the freezing room of household refrigerator is between B15 ℃ and 18 ℃), and the temperature difference is within 120 ℃. Therefore, the heat-resistant glass dish will not burst. It can not only be refrigerated and frozen, but also be used in dishwasher, microwave oven and electric oven.
Tempered glass is easy to crack
We often see some news about the explosion of glass tableware on the Internet. What kind of glass will explode? Ordinary glass and tempered glass have a high probability of explosion. However, it is very rare to use ordinary glass to make water cups and tableware in the market. Most of them use tempered glass and heat-resistant glass.
There are two main reasons for the explosion of tempered glass: first, the internal stress produced in the production process.
In the production of toughened glass, after melting at high temperature, it is directly cooled in extremely cold environment. In the process of production, large internal stress will be produced. In case of external force impact, self explosion and splash will occur. The heat-resistant glass melting process is different from the direct cooling of tempered glass, but put into the slow cooling furnace for slow cooling, which can consume the internal stress of the glass, so the glass structure is more stable. Although there will be rupture in the process of use, it will not produce the phenomenon of burst and flying explosion. Secondly, the toughened glass contains impurity nickel sulfide, which exists inside the glass and affects the stability of glass structure. Therefore, in daily use, it is not recommended to put ordinary glass and toughened glassware into microwave oven for heating, which is easy to cause safety hazards.
Safety is ensured by correct use
Heat resistant glass can withstand the sudden change of heat and cold. Why do some cracks occur? In the normal use process, if the glassware is subject to vibration, it will produce small cracks which can't be seen by the naked eye, which affects the stability of the structure. When it is affected by external forces, it may break. Therefore, in order to avoid rupture and other problems in daily use, the following matters should be paid attention to:
1. When put into the refrigerator freezer, the volume should not exceed two-thirds of the container; when the glassware is closed or semi closed, avoid containing liquid such as juice, broth, milk, congee, etc. Because the volume of frozen food expands, it will also lead to product damage.
2. When heating in the microwave oven, be sure to open the cover. Although the box cover is made of PP (cold / heat resistant temperature B20 ℃ - 120 ℃), and the sealing strip is silicone resin gasket (cold / heat resistant temperature b40 ℃ - 200 ℃), due to the influence of thermal expansion and contraction, the box cover can not be opened or deformed, which will affect the sealing performance of the product.
3. Use the steamer carefully, such as steamed fish, steamed egg soup, etc. the pressure of the steamer is easy to react with the heat-resistant glass, resulting in slight cracks in the glassware.
4. Avoid using steel ball when cleaning to avoid scratches. Avoid beating with hard objects such as steel spoon to avoid damage.
Contact Us skype:tscasecn wechat:rocway