The impeller of RCN-series pumps is of closed type designed with wide cross sections between the blades to pump, without any clogging problems, liquids with non-fibrous solid particles. The casing of RCN/RCNS series pumps is provided with a replaceable wear ring, the casing of RCPN/RCPNS series pumps is provided with a replaceable wear plate to pump liquids with abrasive solid particles. The RCN-RCPN/RCNS-RCPNS series pumps are suitable for use in the pulp and paper industry, the sugar industry, the chemical industry, in iron metallurgy, in the food processing industry