Knoll Maschinenbau GmbG

CIP Cleaning-In-Place for Progressing Cavity Pumps


A residue-free cleaning of pumps must be possible, preferably on location. Cleaning-In-Place (CIP) is a system designed for cleaning and disinfecting without major disassembly and assembly work of pipes, tanks and (of course) pumps in full compliance with hygiene standards and legal specifications.

The key factor is that different rinsing processes can be applied with a given flow rate, so that absolutely no residual dirt is left behind. But how to apply this idea on progressing cavity pumps?

KNOLL Maschinenbau has designed its MX-Pumps for a flow rate of at least 1.5 to 2.0 meters / second for all the rinsing. In addition to that the rotor-stator unit can be partially circumvented by using ports and an additional rinsing line (so-called bypass CIP). Depending on the capacity of the MX-Pump it can also clean itself, so that neither bypass nor additional ports are required.

Under such circumstances the pump ingests the cleaning agent and carries the fluid through its dead space free design with an optimal inflow. No additional CIP pump is required achieving a clean line in compliance with EHEDG requirements, as testified in an expertise from the Research Center Weihenstephan of the Technical University of Munich in April, 2010:

“The test results show that the progressive cavity pump is ready for cleaning. … No problem areas exist that would affect the cleaning effectiveness. … The pump can be cleaned without bypass CIP and has therefore less hygienic problem areas.”

Of course the cleaning cycle will always depend strongly on the application of each pump. As an example, the following steps are recommended:

Leftover Remove: The discharge of the pump before any cleaning process;
Short Pre-Rinse: A quick wash (in a target tank) to prevent waste water;
Purging: The removal of loosely adhering dirt with fresh water;
Cleaning: The stripping and washing away of all adhering dirt with a cleaning solution;
Intermediate Rinse: Rinse the cleaning solution off as well as any rests of dirt;
Disinfection: A further purification step for the reduction of microorganisms;
Rinsing: The (final) rinsing of disinfectants with fresh water.

KNOLL Maschinenbau strongly recommends the use of fresh water for pre-rinsing, a 1-2% sodium hydroxide solution at 60-80 degrees Celsius as alkaline rinse, fresh water as intermediate, nitric acid 1-1.5% at 50-70 degrees Celsius as acidic flushing and fresh water for the final rinse. If other cleaners or disinfectants are to be used, we strongly recommend to contact us before doing so, as it is not guaranteed that the pump is resistant to these materials in any case.

Finally, it should be mentioned that the high serviceability of the MX-Pump allows quick and easy disassembly for cleaning. The components of the pums can be either cleaned manually or run through a utility room and washing line. To simplify the dismantling of the pump KNOLL offers a broad range of helpful tools.