I. Product Introduction

The NB/T47017 pressure vessel sight glasses, also known as equipment sight glasses, are products used to observe the changes in the medium inside chemical, petroleum, cosmetic, and other industrial equipment containers. Operators adjust or control the filling quantity based on the displayed conditions to ensure that the medium within the container remains within the normal range. Sight glasses are required on containers such as liquefied gas tanks, tanker trucks, gas-liquid phase reactors, reaction kettles, etc., to prevent accidents caused by overfilling or to avoid the imbalance of material reactions due to excessive feed.

Section II: Structural Format

Section 3: Selection Criteria

Mirrors should be selected correctly based on the medium, working pressure, and temperature of the pressure vessel.

1. Pressure vessels for liquefied gases containing highly flammable and extremely toxic, highly hazardous substances should use small-bore high-temperature, high-pressure sight glasses and be equipped with protective devices to prevent leakage.

2. Low-pressure vessels are equipped with low-pressure sight glasses, with larger diameter sizes available for selection.

3. For containers used outdoors in cold regions, or where there is a significant difference between the medium temperature and the ambient temperature, a material with a higher rate of temperature change should be selected for the viewing window.

4. In areas with insufficient lighting, choose container view mirrors with lighting fixtures, and select the explosion-proof grade based on the on-site conditions.

4. Installation Precautions

1. Field installation requires disassembling the sight glass, and protective measures should be taken for the glass and gaskets to prevent damage.

2. After welding the joint or elbow, assemble carefully. When tightening fasteners, ensure even and symmetrical force to prevent glass damage.

3. Once glass and gaskets are found to be damaged, they should be replaced immediately.