Suitable for use with sewage water in domestic, civil and industrial applications or in any other situation, such as with water mixed with mud, with groundwater and with surface water, where the water contains suspended solids. They are suitable for use in applications such as for draining flooded areas such as cellars, underground car parks, car washes, for emptying cesspools and for sewage disposal. These pumps distinguish themselves for their reliability, which can be best appreciated under automatic operating conditions in fixed installations.