Tripling service life in a waste water treatment plant

xLC® stator adjustment system permits situation-specific adaptation on NEMO® progressing cavity

Look behind the scenes
The thickened sludge of a waste water treatment plant should be boosted into an intermediate tank. “The solids content is more than eight percent, so that the wear caused by the medium is expected to be very high”, says the head of the purification waste water treatment plant. “Also the nature of the medium is very important for the high wear. It contains iron salt, aluminum salt und also iron from the local industrial plant.

Challenge accepted
During the purchase it was very important for the responsibles involved, that the aggregate is very dependably and easy to service. Also a long life time was very important to them.

Excellently solved
They chose the FSIP®-model of the NEMO® progressing cavity pump from NETZSCH, which is very friendly in service. The design of the pump is special for its large inspection covers: Centrally planned on the edge between pump housing and stator so that it is easy to get access to the sleeve coupling. “It is only necessary to unbolt one screw to separate the rotor-stator-element from the coupling rod”, says Mikael Tekneyan, design engineer at NETZSCH. “After that it is easy to take out the rotating part as well as the rotor-stator-element. The interior of the pump now is freely accessible from flange to flange. “As a result all wearing parts of the progressing cavity pump can be replaced without removing the pump from the pipework. All parts can be removed to the side or the top, so that there is no extra service length needed.

Threefold durability with the xLC® Stator-System reached
The pump features the new developed xLC® stator adjustment system, which allows the operator to regulate the iFD-Stator® 2.0 and increase the lifetime of the pump. In this particular case the component increased the operating time of the pump from 8.000 to 24.000 hours before an exchange of the stator became necessary. The functioning of the xLC® system is based on the proven technology of the iFD-Stator® 2.0. The iFD-Stator® is a dual system in which the aluminum casing and the elastomer are separate parts. The pump housing is split into two parts and the elastomer stator can easily be removed. Since the preload between the elastomer and the rotor is set only when tightening the stator rods, the elastomer part can be easily pushed onto the rotor. Only by the axial compression during assembly of the pump, it receives the optimal dimensions for the operation. A defined stopping ensures a constant preload and a reliable sealing. The xLC® unit fits on the collar of the elastomer part, allowing it to be pulled or pressed. By axial compression of the stator elastomer it is possible to compensate wear in the rotor-stator system and restore its performance. How it works: If a readjustment of the stator becomes necessary due to a performance loss of the pump, you adjust the system by only 2 adjusting nuts and thereby the elastomer insert is compressed in the metal housing, once more building a reliable sealing line with the rotor. A scale with seven defined stopping points facilitates a step-by-step adjustment of the stator and at the same time shows the remaining potential until the stator has to be changed.


Technique

Product: NETZSCH FSIP® version of the NEMO® eccentric screw pumps

Medium: thick sludge eith solids content above 8 %

Delivery rate: 20 - 30 m³ / h at 7 bar


  • The xLC® unit is based on the proven iFD-Stator® 2.0
  • Its separation of elastomer and stator tube makes ist comfortable adjustment possible
  • Axial pressure on the elastomer improves the sealing line
  • An improved sealing line increases the flow performance

Literature