The Best Equipment for Process Observation

Valves, tubes, pressure gauges, and thermometer in boiler room.

While our eyes remain our best tool for seeing what’s taking place in day-to-day life, we sometimes need some help when dealing with complex industrial processes. This is where process observation equipment comes into play.

Process observation equipment typically falls into two categories — sight glasses (also called sight glass windows) and site flow indicators, which are usually used in process pipelines. There are many other kinds of instruments available for these tasks, however, including sight glass lights, process vessel cameras, magnetic level gauges, and hygienic bubble traps.

Process observation equipment is used in a broad range of industries, including utilities, pharmaceuticals, biofuel, food and beverage, wastewater, and chemical/petrochemical.

Here’s a closer look at some of the most common observation tools available:

Sight glasses

Sight glasses are clear glass tubes or windows installed in tank and boiler systems to allow for observation of the processes happening inside the container, ensuring optimal safety, quality, and performance. Traditionally, a sight glass consists of a glass disc mounted between gaskets. A sight glass window, on the other hand, consists of glass fused to a metal frame. Making the sight glass window one piece improves its structural integrity, as the metal can absorb the stress of mounting.

Due to their high strength, sight glass windows are often used in boilers and other pressurized systems. These windows are also valued for their cost efficiency and ability to be reused. When a sight glass is installed on a tank with a lighting component, the tool is referred to as a sight port window, or a viewport.

Sight glasses are most often used to monitor fluids in pipelines, watch the pressure in boilers, and ensure pilot lights and heating elements are functioning properly in heating systems.

Sight flow indicators

These are used in pipes to gauge the direction, color and clarity, and flow rate of liquids. A sight flow indicator has at least one window and is mounted to the pipeline via flanged, threaded, or sanitary clamp connections. These observation tools can be used on pipes as large as 16 inches wide. In addition to being very simple to use, sight flow indicators are also very cost-efficient.


Sight glass lights allow for easy examination of vessel interiors. A wide range of lighting options are available, including non-EX lights, explosion-proof lights, and fiber optic lights. Offered in a range of sizes, from small to large, these lighting components can be made of traditional halogen, LED, or fiber optic materials.

Level gauges

Liquid level gauges determine the level of liquid in a process tank. They offer great durability — especially in harsh environments — and can easily withstand high temperatures and pressure. These gauges can also be read at a distance. They offer heightened visibility, require low maintenance, and reduce the likelihood of leaks compared to sight glasses — which is crucial when dealing with flammable or toxic products.

Sanitary flow indicators

Much like sight flow indicators, sanitary flow indicators monitor the flow of fluid. They detect the presence or absence of solutions and allow fluids to be easily observed for turbulence, color, and clarity — especially in high-purity applications.

The Importance of Process Observation Equipment

A wide range of industries makes use of process observation equipment to enhance visual observations and to ensure that the progress of various stages of manufacturing processes are meeting expectations. While the eyes provide valuable insight, these instruments go the extra step, verifying human observations and providing ultimate peace of mind.





Image Credit: Matveev Aleksandr/

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