We incorporate the latest in terminal header design using single
or dual seal power cable penetrations.
As a supplier of submerged motor pumps operating in hazardous environments, Nikkiso Cryo has extensive experience in the selection and design of the proper electrical components to ensure a safe and certified system. Our electrical systems incorporate the latest in terminal header design using single or dual seal power cable penetrations. These systems can be purged with nitrogen gas to remove moisture from the boundary section between cold and warm, and the purge gas pressure can also be monitored to determine if leakage exists. Electrical systems are supplied to meet plant specifications as well as US, European and any other international codes as required. The systems supplied by Nikkiso Cryo are of the highest quality and are fully tested prior to
shipment to ensure the highest level of reliability.
As a result of Nikkiso Cryo's research and development and through our Aftermarket Service organization, operating personnel can be trained to interpret data acquired from the condition monitoring system. Nikkiso Cryo's research and extensive experience allows for correlation of monitoring specific vibration modes with specific operating and wear conditions. Condition monitoring and trend analysis has the potential to provide more complete diagnostic information on an operating pump than physical inspection of the disassembled pump. This facilitates optimum timing of maintenance considering factors of reliability, operation and costs. Condition monitoring permits scheduling maintenance only when essential and indicates the need for immediate maintenance to prevent outages and loss of production.
Ultimately, condition monitoring saves money through
longer, more efficient pump life and strategically planned maintenance. The feedthroughs and instrument junction boxes supplied on the pumps to enable the cables to pass through from the vessel or tank to the outside are selected and designed for use in the hazardous areas where the pumps are installed for a safe and reliable installation. The system supplied can be monitored with most monitoring systems for display in plant control rooms, trend monitoring and machine diagnosis.
Monitoring Pump vibration is an excellent means to determine pump condition. However, this is particularly challenging for submerged motor cryogenic pumps which have no exposed surfaces or shaft for making direct measurements from the
outside of the containment vessel. Nikkiso Cryo can supply piezoelectric accelerometers designed for use directly submerged in the pumped liquid, mounted on the pump housings, and can also locate accelerometers on the outside of suction vessel mounted pumps to provide monitoring of pump vibration. These sensors can
measure pump acceleration vibration directly and, with signal conditioning, provide velocity and displacement amplitude data. The condition of internal parts and the extent of wear can be determined by trend monitoring and frequency analysis.
Nikkiso Cryo pumps include an automatic axial thrust balancing mechanism which utilizes pressure to produce zero net thrust loading on the bearings. This is accomplished with a variable, axial orifice which controls the pressure entering the balance drum.
Fluid enters into the variable orifice onto the lower face of the balance drum producing "lift' of the rotating assembly. The balance drum outer clearance provides a fixed orifice which reduces the pressure as it passes through to the upper surface.
During operation, the variable orifice adjusts automatically until the two pressures above and below the balance drum reach equilibrium, which results in very stable and reliable operation with no thrust loads on the bearings throughout the entire flow range.
During performance testing of Nikkiso Cryo pumps, axial shaft position is measured to assure the system is balanced and no load is being taken up by the bearings.