Choosing the Right Sight Glass: Differences Between Borosilicate, Quartz, and Tempered Glass

Choosing the Right Sight Glass: Differences Between Borosilicate, Quartz, and Tempered Glass

When selecting sight glass for industrial or laboratory applications, the choice of material directly affects performance, safety, and durability. Among the most common options are borosilicate glass, quartz glass, and tempered glass. Each has unique properties that make it suitable for specific environments.

Borosilicate glass is widely used because of its excellent thermal shock resistance and chemical stability. With a low coefficient of thermal expansion, it can withstand rapid temperature changes without cracking, making it ideal for reactors, pressure vessels, and chemical observation windows. Its affordability and versatility further strengthen its position as a popular choice.

Quartz glass, on the other hand, offers superior purity and optical clarity. With outstanding resistance to high temperatures—often exceeding 1000°C—it is the material of choice for environments where extreme heat and ultraviolet transmission are required. Its high transparency also ensures accurate visual inspection, which is critical in semiconductor, optical, and scientific applications. However, quartz glass is more expensive and can be more brittle compared to borosilicate.

Tempered glass is processed with heat treatment to increase its mechanical strength. Unlike borosilicate or quartz, it is not as resistant to high chemical or thermal stress, but it excels in safety. When broken, tempered glass shatters into small, blunt fragments instead of sharp shards, reducing injury risks. This makes it suitable for lower-temperature, high-impact environments where safety is the top priority, such as machinery inspection windows.

In conclusion, choosing the right sight glass depends on the operating environment. Borosilicate offers balance, quartz ensures extreme performance, and tempered glass prioritizes safety. Understanding these differences allows engineers and users to make informed decisions for reliable and efficient applications.