As a sight glass tube supplier, I share this with you.
Using a sight glass is probably the easiest way to measure the liquid level. The observation mirror is outside the water tank. This lets you see the liquid level through the glass. The scale marks on the sight glass indicate the liquid level. The main drawback of this method is that it only shows part of the liquid level in the container.
You can see the liquid level when the container has a clear part or when the liquid flows through a clear tube. The advantage of using a shut-off valve with a bypass pipe is that it is easy to disassemble for cleaning.
Sight Glass Type Level Gauge
Type of level gauge:
Transparent Level Gauge
The transparent level gauge has two pieces of clear glass. Each side holds a liquid chamber. The liquid level shown comes from the different transparencies of the two media. For water and steam use, the illuminator goes on the back of the meter. The light directs upward into the water column.
When light hits the surface between water and water vapor, it reflects back to the observer. This reflection lets the observer see the bright surface of the water.
Electromagnetic level gauge
The magnet with the float tracks the liquid level in the chamber. This level matches the liquid level in the tank.
The two-color baffle shows the position of the float in the room. A magnet holds this baffle and sets it on the outside of the device. It turns 180 degrees to show a single color along the path of the float.
Reflection level gauge
The reflective level gauge relies on the different refractive indices of liquid and vapor. The liquid column sits in the recess of the liquid chamber. This chamber lies behind the sight glass that attaches to the gauge body. The observation mirror has a right-angle groove on its side that faces the liquid and vapor space. The gauge can absorb or reflect the light from outside. This depends on whether it enters the liquid or vapor space. When light hits a groove in the vapor space, it reflects off the opposite surface. Then, it bounces back in the viewing direction.
So, the vapor space appears silvery white. When light hits the groove’s surface in the liquid, it gets fully absorbed. So, the liquid behind the glass looks black. These gauges measure the liquid level in the container.
The sight glass is also not suitable for dark or dirty liquids. Don’t use this type for measuring hazardous liquids. The glass tube can break easily. If the meter is cooler than the process temperature, condensation can form on its outside. This reduces the reading’s accuracy. The simple sight glass is an older technology. It’s rarely used in automatic control applications.
Our company has a sight glass type level gauge for sale; feel free to contact us.
