THE FACILITY to monitor and detect a problem on any piece of process equipment, before it leads to potentially more significant disruption or downtime, would certainly be viewed as an advantage in most production situations.
This is the thinking behind a new monitoring device incorporated within Nikkiso Canned Motor Pumps, available through UK-based Michael Smith Engineers.
The E-Monitor electric bearing monitor system alerts operatives to potential problems in the pump motor by detecting the condition of the bearings. Changes in the position of the rotor, compared to its normal position within the canned motor, are detected by eight probes within the stator winding.
Any variation alters a signal which is indicated on coloured LEDs visible through a sight glass positioned on top of the terminal box housing of the pump.
Indication of wear is progressive. Green LEDs confirm operating conditions are good, yellow LEDs indicated that wear or imbalance is occurring and caution is required, while red LEDs indicate that the pump should be stopped and wear or hydraulic conditions must be checked.
The E-Monitor allows a range of conditions to be indicated including radial and axial wear of the front and/or rear bearing axial wear of the thrust bearing, abnormal axial position of the rotor, the direction of rotation and that the power supply to the unit is on.
As Nikkiso pumps incorporate a thrust balancing system, thrust bearings do not usually wear excessively and so axial wear on the E-Monitor indicates operation outside the design limit is causing hydraulic imbalance of the rotor.
This can be as a result of a number of causes including cavitation, dry-running or vapour locking.
Nikkiso non-seal canned motor pumps are ideal for handling corrosive, aggressive or expensive liquids which cannot come into contact with the atmosphere.
These compact, self-contained pumps benefit from features such as no seals, no coupling, reduced number of pump/motor bearings, along with primary and secondary leak containment.
Suitable applications are therefore found in the chemical industries.
The E-Monitor feature is available on standard Nikkiso Canned Motor Pump units up to 132kW, while a remote indicator is possible using a 0 to 5V or 4 to 20mA signal.
The unit is IP65 protected and is certified to Atex 100A, II 2G EEx d II c G6, suitable for flameproof locations, according to the company.
