A fluid machine includes: a shaft portion; a shroud surrounding the shaft portion and including an inside surface that forms a flow path-forming surface defining a flow path with the shaft portion; a first propeller rotatably provided in the flow path; a second propeller rotatably provided on a downstream side of the first propeller in the flow path; and a motor including a rotor that is fixed to an outer circumferential portion of the second propeller and that is accommodated in the shroud, and a stator that surrounds the rotor via a clearance and that is fixed in the shroud. A portion of the flow path-forming surface on a downstream side of the second propeller decreases in diameter toward the downstream side, and the shroud includes an inlet flow path that is open at a portion between the first propeller and the second propeller of the flow path-forming surface.

The present invention relates to an underwater drone which is an unmanned mobile which can move in the water, and more particularly to a communication system for the underwater drone which performs communication between the underwater drone and a land-based controller (or maneuvering device). The present invention also relates to an airlock apparatus for the drone which transfers the drone into or from facilities or containers, or equipment sealed (or closed) against surrounding environment. The communication system for an underwater drone includes an underwater drone (1) configured to move in the water, at least one transmitting and receiving antenna (2) provided in an area where the transmitting and receiving antenna (2) can communicate with the underwater drone (1) by wireless communication, and a controller or a maneuvering device (5) connected to the at least one transmitting and receiving antenna (2) by a wired cable (4) and configured to control the underwater drone (1).

The present invention relates to an underwater drone which is an unmanned mobile which can move in the water, and more particularly to a communication system for the underwater drone which performs communication between the underwater drone and a land-based controller (or maneuvering device). The present invention also relates to an airlock apparatus for the drone which transfers the drone into or from facilities or containers, or equipment sealed (or closed) against surrounding environment. The communication system for an underwater drone includes an underwater drone (1) configured to move in the water, at least one transmitting and receiving antenna (2) provided in an area where the transmitting and receiving antenna (2) can communicate with the underwater drone (1) by wireless communication, and a controller or a maneuvering device (5) connected to the at least one transmitting and receiving antenna (2) by a wired cable (4) and configured to control the underwater drone (1).

A liquid pressurizing apparatus, comprises a tank provided on a device installation surface for storing liquid so that a fluid level is located above the device installation surface; and a vertical pump including a suction port connected to the tank, multi-stage impellers arranged in a vertical direction, and a discharge port for discharging the liquid passing through the multi-stage impellers. The multi-stage impellers include a first stage impeller positioned at the lowest part of the multi-stage impellers and being configured such that the liquid from the suction port flows into the first stage impeller. The first stage impeller is disposed below the device installation surface.

A liquid pressurizing apparatus, comprises a tank provided on a device installation surface for storing liquid so that a fluid level is located above the device installation surface; and a vertical pump including a suction port connected to the tank, multi-stage impellers arranged in a vertical direction, and a discharge port for discharging the liquid passing through the multi-stage impellers. The multi-stage impellers include a first stage impeller positioned at the lowest part of the multi-stage impellers and being configured such that the liquid from the suction port flows into the first stage impeller. The first stage impeller is disposed below the device installation surface.

The present invention is a transfer or drainage pump, comprising an engine, usually electric, contained in a sealed body, that powers a turbine; said turbine sucks liquid that is close to the suction nozzle, and said liquid is expelled through an outlet duct. The pump includes an external casing with a top lid, a bottom lid and a wall that surrounds the pump, and includes a set of small holes extending over the inferior area of its surface, near the suction nozzle, and a set of bigger holes extending over the superior area of the casing. The present invention also includes a set of space maintainer appliances for the detachment of textile products, sanitary towels, towels, rags that are objects that produce the greater damage to submersible pumps due to the obstruction they can provoke.

The present invention is a transfer or drainage pump, comprising an engine, usually electric, contained in a sealed body, that powers a turbine; said turbine sucks liquid that is close to the suction nozzle, and said liquid is expelled through an outlet duct. The pump includes an external casing with a top lid, a bottom lid and a wall that surrounds the pump, and includes a set of small holes extending over the inferior area of its surface, near the suction nozzle, and a set of bigger holes extending over the superior area of the casing. The present invention also includes a set of space maintainer appliances for the detachment of textile products, sanitary towels, towels, rags that are objects that produce the greater damage to submersible pumps due to the obstruction they can provoke.

An oil field pump is installed within a pipe that connects to an oil field, and feeds accumulated extraction oil in a predetermined direction, the oil filed pump including a rotor with an internal flow path for the extraction oil, a stator installed on the outer circumference of the rotor, a thrust bearing that supports the axial weight of the rotor and the stator, a supply pipe that supplies a portion of the extraction oil in the flow path to the thrust bearing, and a filter that is installed at further upstream on the flow path than the supply pipe along the flow direction of the extraction oil, and traps foreign matter.

A fluid-dynamic pump which is suitable for circulating water in an aquarium includes a rotary device, an electric motor configured to move the rotary device, a pump body which houses a printed circuit board which that controls the electric motor and a temperature sensor that detects the temperature of the water of the aquarium. The temperature sensor is positioned on the pump body.

A circulator is described that is configured to circulate liquids such as water, chemical mixtures, suspensions and the like. The circulator has an oscillation shaft disposed within, for example concentrically disposed within, a support tube that is used to mount the circulator to a support structure. Locating the oscillation shaft within the support tube makes the circulator more compact, achieves better alignment of the oscillation shaft and the support tube, and makes the circulator stronger compared to a circulator where the oscillation shaft is not disposed within a support tube. In one embodiment, the circulator can be used to create a continuous flow of water in a body of water including around marinas, areas around docks, and waterfronts.