This is a very interesting and different form of load cell weighing. Actually another form of “suspended weigher” that is unique to Weigh Sol.
Why Weighing by Displacement?
Designed as an alternative method to mounting a process vessel or storage tank on load cells. It is to measure liquid contents by weight, but, by using a single load cell in suspension. This applies particular in a “retro-fit” situation, typically where it may not be feasible or practically to modify the structure. The modification would not be cost effective, hence the retro fit. The aim of the retro fit would be remove the need for accommodating a more standard load cell support approach.
Weighing Displacers for Vessels and Tanks
The Weighing Displacer will work satisfactorily in most types of vessel or tank. Including one fitted with an internal agitator, and with any liquid product. The technique actual applies Archimedes’ Principle, using buoyancy – in practice very successfully. It can be a very useful alternative to other level-measuring techniques such as radar and ultrasonics as well.
Support a Column of Material
The force needed to support a column of material (the displacer) decreases by the weight of the process fluid displaced. A load cell suspending the display measures this force and transmits it as any standard analogue signal would. This signal goes to the associated weighing electronics.
How Does a Weighing Displacer Work
The physics is thus… the density of the displacer is always more than that of the process fluid. This is so that it extends from the lowest level of the tank to the highest level that needs to be measured. The column displaces a volume of the fluid due to a rise in the process fluid. The displaced volume is equal to the product of cross-sectional area of the column and the level of process fluid in the displacer. A buoyant force, whose magnitude is equal to the product of the displaced volume and the process fluid density exerts an upward thrust on the displacer. This then brings down the force required to support it against the gravitational force. This change is monitored by the load cell linked to the weighing instrument and translates the change in force to level.
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