Johnson multistage pumps include a series of pumps in vertical or horizontal execution. The pumps can be supplied self-priming. The material of construction of the body and impeller is cast iron or bronze. The maximum capacity is 100m3/hr at 35 bar head. The pump consist of an inlet and outlet casing and a number of stages in between. Each stage has a radial diffuser and a matching impeller. The flanges are built according to DIN 2535 ND40. Shaft seal is either by mechanical seals or gland packing.