Look behind the scenes
A regional water company in Northern Italy used two progressing cavity pumps of the NEMO® BY type in block construction design for sludge dewatering. One of the pumps has being used to convey sludge into the centrifuge, while the second was permanently in standby mode in order to step in if there were faults or in the event of maintenance work.
For conventional progressing cavity pumps, maintenance of the conveying elements had required a relatively large amount of effort. In order to remove the rotor and stator, you had to dismantle the whole pump from the pipework. Replacing the conveying elements meant removing the end connection, pulling the stator off the rotor and dismantling the sucker rod string. When positioning the pump, this dismantling length therefore had to be taken into account and sufficient room at the front kept clear. Any major work on the pump was thus accompanied by extended downtime, lost production and personnel costs.
In order to increase the system’s cost efficiency by using only one unit in future and to still ensure uninterrupted continuous operation, NETZSCH recommended the replacement with the FSIP® design of the NEMO® progressing cavity pump. We are therefore talking about the “Full Service in Place” concept, because the pump does not have to be dismantled from the pipework. Maintenance work takes a significantly shorter time and resources as well as costs are reduced. The special inspection cover is secured by just five screws that can be removed without any special tools at all in a really short time. After removing the cover only one screw needs to be removed to separate the rotor-stator element from the coupling rod. The rotating units can then easily be lifted out, and the pump interior is freely accessible from flange to flange. The additional dismantling length is no longer required. All in all, this means any wearing part can be replaced in less than half the previous time and customary performance can be maintained in spite of easier maintenance. To work in a particularly easy and resource-efficient way the new pump design can be combined with the iFD-stator® 2.0. This involves a stator system where the elastomer is not vulcanised into the housing, as is otherwise common, but is fixed by axial compression. By separating the steel sleeve and elastomer stator, the latter can be quite easily removed together with the rotor. This makes maintenance even easier. This solution also increases the cost effectiveness of the system: During the entire conveying process roughly 25 percent less energy is consumed and the drives of the pumps can have correspondingly smaller dimensioning. Furthermore, because of the lower load, the stators last approximately twice as long – in conjunction with simple maintenance thanks to the FSIP® concept, downtimes are reduced to a minimum.