Abstract: A pump assembly includes a housing having two parts with internal cylindrical chambers having openings for the inlet and outlet of a pumped fluid, and two longitudinally deformable bellows fastened inside the respective parts of the housing. The opposite end of each bellows has a plug. On the end surface of the housing the bellows are connected to is an opening for the inlet of a working fluid into the corresponding internal chamber. A hydraulic system for controlling the pump assembly includes a tank containing a working fluid, a positive displacement pump, two independent hydraulic pipelines, and a system of valves for alternately connecting the bellows' internal chambers containing working fluid to the pipelines. The internal chamber of each bellows is alternatingly connected to the positive displacement pump for supplying working fluid by a first hydraulic pipeline and to the working fluid tank by a second hydraulic pipeline.

Abstract: The invention relates to pump assemblies for pumping fluids with a high solids content. The present assembly comprises a housing having two parts with internal cylindrical chambers having openings for the inlet and outlet of a pumped fluid, and two longitudinally deformable bellows fastened inside the respective parts of the housing. The opposite end of each bellows is provided with a plug. On the end surface of the housing to which the bellows are connected is an opening for the inlet of a working fluid into the corresponding internal chamber. A hydraulic system for controlling the pump assembly is configured as a tank containing a working fluid, a positive displacement pump, two independent hydraulic pipelines, and a system of valves capable of alternately connecting the internal chambers of the bellows containing working fluid to the pipelines.