It is crucial to have a reliable and accurate measurement of material stored in vessels, silos or bins. Precise inventory management allows you to know when to refill, avoid overfill and keep the most up to date inventory records. There is a variety of weighing systems used to measure bulk inventory, and they all have one thing in common. At some point, operators experience inventory loss, also known as drift, that causes inventory records to be inaccurate.
Drift is apparent weight change when there has been no material movement. If you are experiencing this phenomenon, then I am sure you are asking the question, “Why does drift occur in silos and other vessels?”. Most often, drift is caused by foundation changes or vessel movement due to thermal heating and cooling.
Inventory loss is frequently influenced by environmental factors such as solar radiation. Some solar radiation produces movements in the vessel. As the vessel moves, weight of the material is redistributed within the silo. This redistribution of weight often result is a different reading from the weighing system without adding or subtracting material. The diameter of the vessel is capable of expanding and contracting as much as ½’ due to climatic conditions such as heat. If the support structure is rigid then the vessel will move around and cause bowing in the supports.
Piping and plumbing are structural factors that can cause inaccuracies due to weight transference. Proper decoupling of piping and plumbing, solid foundation support and minimizing of catwalks and other structural add-on will improve the accuracy of the system.
Your vessel must be structurally sound to get the most accurate weight reading. If a vessel is unstable due to a weak foundation or unsteady support, the force of wind can cause movement that could result in false changes in readings from time to time.