HG/T21575-1994 Illuminated Neck Sight Glass, available in three models: A, B, and C, suitable for various industrial environments such as chemical, petroleum, food processing, etc. It enables real-time, accurate, and intuitive observation of various stages of the process.

Main technical parameters of the flange sight glass:
1. Shell material: Carbon steel, stainless steel (SUS304, SUS304L, SUS316, SUS316L, 321, 2205, TA2, etc.)

2. Window material: Tempered glass, borosilicate glass, quartz glass.
3. Operating temperature: The maximum allowable temperature for glass is 150°C, with a rapid temperature change range from 120°C to 20°C. The maximum allowable temperature for borosilicate glass is 280°C, with a rapid temperature change range from 230°C to 20°C. The maximum allowable temperature for quartz glass is 800°C, with a rapid temperature change range from 550°C to 20°C.
4. Operating pressure: Soda-lime glass: 0.6 MPa.
5. Borosilicate glass: 0.6~1.0 MPa.
6. Quartz glass: 0.6~2.5 MPa.
7. Sealing ring material: PTFE, oil-resistant asbestos, rubber, etc.
8. Manufacturing and inspection standards: Designed, manufactured, and accepted in accordance with "HG21575-94 Sight Glass".