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Vietnam's Rang Dong runs production of thermos spare parts

Founded in 1961, Rang Dong Light Source and Vacuum Flask Joint Stock Company was the first in Vietnam's northern region to start production of vacuum flasks, also known as thermos. The Rang Dong vacuum flask has since become a favorite brand among millions of Vietnamese. Apart from developing various styles and shapes of the product, the Hanoi-based company also manufactures thermos spare parts such as glass refills and rollers.

Glass Refill

Most of the raw materials, such as limestone, dolomite and sand are sourced from domestic suppliers in Hai Phong city, Ha Nam province and Van Don of the northern province of Quang Ninh. Other materials are imported from countries such as the United States and China.

Among them, sand is the most essential raw material. In order to ensure the quality of the glass, the sand particle size used for production must be below 1.4 millimeters. They will be sieved carefully to remove impurities before being dried to specific moisture content.

Another material is glass fragments. The glass fragment is used in the furnace to lower the temperature inside. If all raw materials are used for melting, the furnace temperature can reach 1,700 degrees Celsius. Despite the fact that the glass fragments melt faster, the furnace temperature only reaches 1,500 degrees Celsius. The glass fragments are contribute to waste reduction.

Rang Dong uses all these materials to make the glass refill. The thermos part is made up of two glass 'jars' that are placed one inside the other and separated by a layer of vacuum. The company uses two assembly technologies, namely waist sealing and bottom sealing, to create a complete glass refill.

The inner surface of the outer bottle and the outer surface of the inner bottle will then be plated with a nano-silver layer to improve heat radiation. The gas inside the gap between the inner and outer bottles will be sucked and sealed until the pressure inside the gap reaches minus 2 to the tenth Torr. The vacuum inside the gap aids in reducing heat transfer.

Given the multi-layer structure, Rang Dong's glass refill can help retain hot or cold beverage for a long time.

The safest material for food contact is neutral glass. That is why Rang Dong continues to develop a line of vacuum flasks to protect customer health.

Roller Manufacturing

Each stainless steel sheet roll is cut into numerous sheets of varying sizes. The edges of these pieces are then bent and folded. Workers will print logos on the casings. They will then be taken to the conveyor and gathered with the glass refill, after which the workers will assemble all components to make the finished products.

The other side of the assembly lines is the plastic processing area. Rang Dong imports Polypropylene and ABS particles from Saudi Arabia, the quality of which is tested before processing.

Rang Dong can customize the logo and pattern as per customer's needs. After that, the printed parts will be dried to make them durable.

Should you have any questions or request a quotation of Rang Dong products, please send us an email to: export@rangdong.com.vn.

Websites: en.rangdong.com.vn and vacuumflask.rangdong.com.vn

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