What is a sight glass？

The working principle of valve sight glass and related knowledge

The installation size is small, the driving torque is small, the operation is simple and fast, and it also has good flow adjustment function and closing and sealing characteristics. The sight glass is the dominant sight glass in the use of large and medium caliber, medium and low pressure.

Valve sight glasses are divided into two categories: pipe sight glasses and equipment sight glasses
Uses: The sight glass can be used in high temperature, strong corrosive, easily poisoned, dangerous, and easy to crystallize chemical towers to ensure their safe production.
Structure: The sight glass is mainly composed of sight glass bottom plate, sight glass, valve components, etc.

In the process of urea production, in the medium and low pressure tower with sight glass, due to the high working temperature and strong corrosiveness of the liquid, it is easy to cause damage to the sight glass of the liquid level meter, deformation of the sight glass bottom plate, and the installation of the sight glass in the process In, sometimes due to uneven force, it is easy to cause the sight glass to break. If it is not found in time, leakage will inevitably occur after driving, and then the entire system must be shut down for hot wash replacement. This not only brings difficulties to the long-term safe operation of the system, but also seriously affects the efficiency of urea production.

According to the characteristic of "liquid is easy to crystallize under the influence of temperature" in the urea production process, combined with the characteristics of various shut-off valves and heat preservation valves, after long-term observation, exploration and thinking, the design uses the bottom plate of the sight glass as the valve body, and the bottom plate is placed on the bottom plate. , Add a valve to the lower liquid inlet to control, install a sight glass level gauge on the bottom plate of the sight glass, and heat the surrounding steam to prevent the liquid from cooling and crystallizing to form a false liquid level. The bottom plate of the sight glass is welded to the tower container, and the heat of the tower body is used to increase the temperature of the bottom plate of the sight glass to further prevent liquid crystallization. If the sight glass leaks or the sight glass is damaged, the valve on the bottom plate can be closed first. This not only serves the purpose of replacing the sight glass without stopping the vehicle, but also ensures the normal production and the personal safety and working environment of the operators. Safety is also guaranteed. After the Feicheng Chemical Fertilizer Plant tested on the urea pre-distillation tower, it was successful once and filled the gap in the field of controllable heat preservation sight glasses.