Ever wonder how equipment operators determine how much product is in their stainless steel tanks?  They are opaque – you can’t see through them. 

One method that has been used on small atmospheric tanks is to equip the vessel with an external liquid level sight tube.  Fittings are positioned on the sidewall near both head-to-shell seams so the clear tube can be mounted vertically on the exterior of the tank (see yellow highlight in sketch).  The contents of the tank free-flows into the tube mirroring the level of the product inside the vessel. 

Using a liquid level sight tube allows the operator to visually monitor the product level, seeing that it’s half full, three-quarters full, etc.  Alternatively, by using mathmatical equations, they can calculate the volume in gallons (or liters).  Once they know the number of gallons per 1-inch of sidewall and the capacity of the bottom head, they can quickly calculate the volume based on the number of inches of product in the tube.

There are other visual methods for monitoring product in the tank such as sight glasses mounted to fittings in the top head or the sidewall.  Electronic liquid level indicators and load cells for tank weighing are other popular options.  Whatever your requirement, SFI can help!

Liquid level sight tube for product measurement

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