IMPROVED CLOG RESISTANCE TESTING METHODOLOGY

Abstract

A gap exists between the impeller and the drive unit. The gap differs in different pump depending on its design and application. Wastewater materials form residue at the gap and clog pumps. This master thesis aimed to design an improved clog resistance testing methodology for wastewater pumps. A case study of pumps within the small range Flygt product portfolio has been used for this work. This methodology is to be implemented to assess upper volume clogging problems for existing hydraulic designs and to aid future design improvements in product development. This work goes through the theory centrifugal pump design, performance characteristics, modern hydraulic design, wastewater management, wastewater pump clogging and modern wastewater materials. Existing methodology for testing and comparing clog resistance ability of wastewater pump has been assessed in relation to how it accommodates evolving modern wastewater materials and limitations established. Wet wipes have been discussed and also established to be a major deterrent in wastewater movement. Two Concepts, which includes a lifting mechanism and a Recirculation concept has been tested and evaluated against a set of decision criteria using a Pugh’s decision making model. The recirculation concept has been adopted and modelled in this work as the final methodology to assess upper volume clogging. Experiments have been design for this methodology and validation tests carried out with pumps and a combination of parts from the small product range. Evident and consistent comparable outcome have been achieved with this methodology to validate its efficiency. Recommendation has been made for a standard measurement approach and further improvement of equipment set-up for this methodology. The impeller lifting mechanism has also been recommended for further work and also in combination with this methodology to assess mechanical properties and involvement of modern hydraulic design with integrated adaptive feature. Keywords: Upper gap, upper volume clogging, clog resistance, Recirculation, lifting mechanism, Pugh’s model, wastewater management, modern hydraulic, wet wipes.