size
In many harsh applications, the load cell sensor can be overloaded (caused by overfilling of the container), slight shocks to the load cell (e.g. discharging the entire load at one time from the outlet gate opening), excess weight on one side of the container (e.g. Motors mounted on one side), or even live and dead load calculation errors. A weighing system with a high dead load to live load ratio (i.e., dead loads consume a significant portion of the system capacity) can also put load cells at risk because high dead loads reduce the weighing resolution of the system and reduce the accuracy. Any of these challenges can lead to incorrect weighing or damage to the load cells. To ensure your load cell provides reliable results under these conditions, it must be sized to withstand the maximum live and dead loads of the weighing system plus an additional safety factor.
The easiest way to determine the correct load cell size for your application is to add the live and dead loads (usually measured in pounds) and divide by the number of load cells in the weighing system. This gives the weight each load cell will bear when the container is loaded to its maximum capacity. You should add 25% to the number calculated for each load cell to prevent spillage, light shock loads, unequal loads, or other severe loading conditions.
Note also that in order to provide accurate results, all load cells in a multipoint weighing system must have the same capacity. Therefore, even if the excess weight is only applied at one load point, all load cells in the system must have greater capacity to compensate for the excess weight. This will reduce weighing accuracy, so preventing unbalanced loads is usually a better solution.
Selecting the correct features and size for your load cell is only part of the story. Now you need to install your load cell properly so it can withstand your harsh conditions.
Load cell installation
Careful installation of your weighing system will help ensure that each load cell will provide accurate and reliable weighing results in demanding applications. Make sure the floor supporting the weighing system (or the ceiling from which the system is suspended) is flat and leaded, and strong and stable enough to support a full load of the system without buckling. You may need to reinforce the floor or add heavier support beams to the ceiling before installing the weighing system. The ship’s supporting structure, whether consisting of legs beneath the vessel or a frame suspended from the ceiling, should deflect evenly: usually no more than 0.5 inches at full load. Vessel support planes (at the bottom of the vessel for floor-standing compression-mounted vessels, and at the top for ceiling-suspended tension-mounted vessels) should not slope more than 0.5 degrees to account for temporary conditions such as passing forklifts or changes in material levels of nearby vessels .If necessary, you can add supports to stabilize the container’s legs or hang the frame.
In some difficult applications, high vibrations are transmitted from various sources – via vehicles or motors on nearby processing or handling equipment – through the floor or ceiling to the weighing vessel. In other applications, a high torque load from a motor (such as on a mixer supported by a load cell) is applied to the vessel. These vibrations and torque forces can cause the container to deflect unevenly if the container is not installed properly, or if the floor or ceiling is not stable enough to properly support the container. Deflection can produce inaccurate load cell readings or overload the load cells and damage them. To absorb some vibration and torque forces on vessels with compression-mount load cells, you can install isolation pads between each vessel leg and the top of the load cell mounting assembly. In applications subject to high vibration or torque forces, avoid suspending the weighing vessel from the ceiling, as these forces can cause the vessel to sway, which will prevent accurate weighing and may cause the suspension hardware to fail over time. You can also add support braces between the vessel legs to prevent excessive deflection of the vessel under load.
Post time: Aug-15-2023
