High accuracy calibration method provides rapid verification for weighing systems

Procon Engineering's highly successful ForceCal Force Calibration System for calibrating weighing vessels, silos and hoppers is now ATEX certified for use in zone 1 hazardous areas.

Ensuring that weighing systems continue to meet required performance criteria is vital to many processes and commercial transactions. This can only be achieved if regular and effective calibration is carried out to exacting and traceable standards. Although there are a number of well recognised calibration methods, often their practical application in a particular installation may be restricted, especially once the system has been installed and commissioned.

As Rod Massey, Procon's Service Manager explains: "Although as a company we offer a range of calibration methods, selected to meet specific customer requirements, where practical, we prefer to use our Force Calibration System. Methods involving standard test weights or flow meters provide good accuracy but in many applications they cannot be applied without major disruption to the plant. Often it is not possible to apply large quantities of test weights and when flow meters are used there is the high cost of disposing of, or reprocessing, large volumes of contaminated water. In addition, both methods require the vessel to be empty when calibration takes place, resulting in precious plant downtime. By comparison our Force Calibration method can be used whatever the weight in the vessel. This is of great importance if vital components such as load cells or instrumentation need replacing necessitating the need to recalibrate the system. In such cases, this can be carried out without the need to empty the vessel. Now this system is approved for use in hazardous areas, we can deal with every eventuality"

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The system works by placing specially calibrated load cells and force generators (typically hydraulic jacks) in parallel with the load cells supporting the vessel by means of special mounting brackets designed into the structure. By applying load to the calibration load cells through the force generators, the weighing system output can be compared with that of the Force Calibration system at typically 10 points over the weighing range. This method provides a high accuracy, non-intrusive and expedient method of calibrating weighing systems. The load cells are traceable to UKAS standards and give a calibration accuracy of +/- 0.01%. This means that where applicable, in line with ISO 9000 recommendations for calibration, systems can be certified to +/-0.03%. (Three times calibration accuracy). Procon Engineering can provide comprehensive service support and calibration service for a wide range of weighing systems, including batching systems, storage vessels and silos, weigh feeders and belt weighers. With nationwide coverage on a 7x24 basis, customers are assured of experienced support wherever and whenever they need it.