Waterjet propulsion apparatus

Abstract

A waterjet propulsion apparatus comprising a motor, an impeller driven by the motor via a drive shaft, and a power source. A fluid flow-path is formed through the apparatus, the flow-path extending from at least one fluid inlet, through two propulsion passages, each propulsion passage extending from a propulsion inlet to an outlet located at a rear end of the apparatus. The impeller is located within the flow-path, after the at least one fluid inlet, and before the propulsion inlet of the each of the propulsion passages. The motor is located outside of the flow-path, between the two propulsion passages, and behind the impeller. The apparatus is advantageous in that it provides a compact and lightweight construction that can, for example, be used as part of a personal marine propulsion device that can be used by an individual.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims priority to United Kingdom Patent Application No. 1809698.2 filed on Jun. 13, 2018, the entire contents of which are incorporated by reference herein.DESCRIPTIONField of the Invention[0002]The present invention relates to a waterjet propulsion apparatus. The apparatus is particularly suitable for use in a personal marine propulsion device (sometimes known as dive propulsion vehicles) that can be held by an individual or otherwise attached to an individual to aid their propulsion through and under water. Such devices are generally used for leisure purposes but also have applications in any other situation in which it might be desirable to propel an individual through water without the use of a larger vehicle.Background[0003]Various personal marine propulsion devices are currently known. Typically, such devices consist of a propeller driven by a motor and a power supply contained within a watertight housing. The prop...

AI Technical Summary

Benefits of technology

[0022]The drive shaft of the apparatus of the present invention may be mounted within the apparatus in any manner apparent to the skilled person. Typically, the drive shaft will be mounted within one or more bearings. Such bearings may be of any suitable type including, but not limited to, waterproof bearings or ceramic bearings. Ceramic bearings may be preferred as waterproof sealing is not required thereby reducing the cost and complexity of the apparatus. The drive shaft may be mounted within the apparatus by means of one or more thrust bearings that act to transfer thrust from the drive shaft to the apparatus. Alternatively or additionally, the drive shaft may be mounted within the apparatus within one or more brass bushes.

[0023]The motor of the apparatus may be a waterproof motor that can be operated in direct contact with water. This may be preferred as it is not necessary to mount such mo

Problems solved by technology

These devices are relatively inefficient and provide only weak propulsion.

However, the length of flow-path required to achieve efficient waterjet propulsion has been consi

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