Various types of sight glasses

The sight glass employs a glass‑sintering sealing process and serves as a hermetically sealed viewing window in industrial equipment, enabling observation of internal operating conditions. By sintering glass to a metal substrate at high temperatures, it achieves a high‑strength, gas‑tight seal, simultaneously providing both optical transparency for observation and pressure‑resistant sealing. It is widely used in refrigeration compressors, pressure vessels, hydraulic tanks, and industrial fluid‑handling equipment.