Gravitation Measurement with Load Cells
*The views and opinions expressed in this load cell article are entirely those of the contributor and are in no way a reflection or indication of Eilersen.com.
You may have often cast an eye over the huge industrial estates which are frequently seen from high speed motorways across the globe. While taking in the awe inspiring view of buildings, pipes and huge towers with different coloured plumes of smoke escaping into the atmosphere you may also notice the huge tanks or silos often with huge stainless steel frames webbing the structure in a futuristic manner, littered within the mass complex of industry. Here we take a deeper look at these tanks and find out how the materials contained within them could be best measured. These tanks and silos can contain all different kinds of materials and products including:
Solids and liquids
Slurries and gases
Fluctuating densities
Any percent solids
Non-contamination
Caustic ingredients
Foaming materials
Uneven settling ingredients
It is usually very important for the actual weight of product/material within the tank or silo to be known at any one time. This is usually achieved by placing supporting load cells within the legs of the tank. Using Eilersen's unique capacitive digital load cells in this manner offers several advantages over more standard load cells. The first and common benefit of using a non-contact load cell provides a more accurate measurement, high levels of tolerances from shocks and vibrations, quicker and more efficient installation and maintenance and if they are used to support each leg of the tank or silo they do not even require any calibration onsite but instead can be handled by the supplier prior to installation.
Allowing a load cell to support each leg of the tank ensures that any movement / vibration within the tank will not affect the measurement reading as the weight would simply move from one leg to another. However even if only one leg is supported by a digital load cell we can still achieve an accuracy of around 1.5%. In installations such as this where not all the legs of the tank are supported by load cells the pipes should also have a high flexibility to horizontal movements. Otherwise the pipes, especially if they are connected to the top of the tank, will be able to shift the load to or from the tank leg with the load cell and thus cause weighing errors.
Eilersen's capacitive load cells can be used in many level monitoring applications including within medical technology, chemical, biotechnology and pharmaceutical industries as well as for food and beverage. This is because the non-invasive design, with no contact between sensor and the material eliminates any contamination issues and helps maintain a sterile environment. The advantage compared to other methods for level measurement is that the measurement is kept outside the tank so there is no contact with the media inside the tank and no special hygienic precautions. Also, the validity of the measurement can be tested very easily by using a known weight.
