Abstract: A single-shaft multistage pump is provided to make small-sized and space-saved possible. The single-shaft multistage pump includes a rotary shaft on which impellers are disposed at multiple stages, bearings and for supporting the rotary shaft, and a balance device adapted to apply, to the rotary shaft, a balance thrust force opposing an impeller thrust force. A water-lubricated bearing is used as each of the radial bearings, and the rotary shaft is supported by the water-lubricated bearings with a balance member of the balance device interposed therebetween.

Abstract: A single-shaft multistage pump is provided to make small-sized and space-saved possible. The single-shaft multistage pump includes a rotary shaft on which impellers are disposed at multiple stages, bearings and for supporting the rotary shaft, and a balance device adapted to apply, to the rotary shaft, a balance thrust force opposing an impeller thrust force. A water-lubricated bearing is used as each of the radial bearings, and the rotary shaft is supported by the water-lubricated bearings with a balance member of the balance device interposed therebetween.

Abstract: A multi-stage diffuser-type centrifugal pump suitable for feeding under pressure a low-temperature fluid such as a liquefied gas. Stages are respectively provided between adjacent ones of impellers provided in a plurality of stages. A cylindrical stage casing is provided in such a manner as to surround the stages, a sealant is provided between each stage and the stage casing to form a channel flow on an inner peripheral surface of the stage casing for flow from an upstream-side impeller to a downstream-side impeller. In addition, the sealant has a coefficient of thermal expansion which differs from the coefficient of thermal expansion of the stage and the stage casing.