When Heap & Partners designed a new valve actuator they specified a customised potentiometer from Variohm. The concept which Heap & Partners started with was simply that the actuator needed to be capable of being fitted to existing valves which in their original state could not be monitored or controlled by a SCADA system. This meant that the actuator needed to have an integral position feedback sensor in the form of a potentiometer, which needed to be capable of being operated from an 8mm diameter shaft and have mechanical stops which needed to be strong enough to take the full force of the actuator without being damaged.
Variohm was able to offer a customised version of its Contelec GL series of hollow shaft units. This customised version, designated the GL80, had an 8mm through-hole and was fitted with two external 3mm diameter hardened pins which were more than capable of withstanding the forces exerted by the actuator.
Four main benefits arose from this solution. Firstly, the GL80 was tough enough to act as a bearing for the external drive shaft, this saved additional expense. Secondly the GL80 has a very low profile which made it extremely easy for Heap & Partners to house it. The third benefit was accuracy the GL80 played its part in allowing a system accuracy of 0.5% to be achieved. The last major benefit was cost – the GL80 is extremely cost effective.