For critical and environmentally sensitive pumping applications, magnetically coupled, “sealless” or “canned” pumps offer a number of clear advantages. But, since the bearings are now inside these pumps, a presence of fluid is needed to remove the heat buildup. Since repair or replacement of one of these nice pumps will require a deep reach into the wallet, an effective monitoring system becomes a good investment.
Valve positioners are devices used to increase or decrease the air load pressure driving the actuator of a control valve until the valve’s stem reaches a position balanced to the output signal from the process variable instrument controller.
Valve controls and feedback