RU2847865C1 - Water jet engine - Google Patents

Abstract

FIELD: shipbuilding.

SUBSTANCE: invention relates to shipbuilding, namely to small vessels. The water jet propulsion system includes a housing in which an impeller is located, connected by a spline connection to the drive shaft for transmitting torque from the vessel's engine and mounted on the propeller shaft by a threaded connection. The propeller shaft is mounted in a cup by means of bearing supports, sealing assemblies and a cone fairing with a sealing ring. A cover is also installed here to absorb axial loads during operation of the water jet propulsion system. The straightening apparatus blades are mounted on the cup, resting on the front side, along the direction of fluid flow, in the impeller housing and pulled together by the nozzle and curtain on the other side to the impeller housing. A replaceable ring nozzle is installed on the nozzle, and a rod for controlling the swivel nozzle is installed on the curtain, and a reverse device damper is fixed.

EFFECT: improved manufacturability, maintainability and serviceability of the design, ensuring the interchangeability of individual blades.

1 cl, 4 dwg

Description

The invention relates to shipbuilding, namely to water jet propulsion systems for ships, small boats, jet skis and other watercraft.

A water jet propulsion unit is known, which is made with a cantilever-mounted impeller in the form of a removable, structurally complete module, which is a body of revolution (patent RU 2357891).

This technical solution, which separates the axial pump into an interchangeable structural unit, uses a design without a straightener, which reduces the overall efficiency of the water jet propulsion system. A disadvantage of this design is increased operating costs.

A water jet propulsion unit is known, comprising a water duct with a water intake and protective grate, an intermediate shaft, an impeller, a straightening vane with a nozzle, a reversing steering device, and an inspection hatch (patent RU 2486100). The invention describes a simplified design and increased reliability of the water jet propulsion unit by using fewer parts and utilizing the straightening vane and nozzle as a single component.

The disadvantage of this type of propulsion is the inconvenience of maintenance and the increased cost of repairs in the event of a breakdown of the straightener blades.

A water jet propulsion system, adopted as a prototype (patent RU 2751366), comprises a shell housing an impeller with a smooth-radius hub. The hub is splined to the drive shaft. The impeller is threaded to the propeller shaft, mounted in a block of straightener blades via bearing supports, seal assemblies, and a cone. Attached to the block of straightener blades is an outlet nozzle with a replaceable annular nozzle and a shutter, which carries a control rod for the rotating nozzle and a reversing device flap. A disadvantage of this design is the technologically complex design of the straightener, which is cast in a single piece, making replacement a labor-intensive task.

The technical problem that the claimed invention is aimed at solving is the creation of a water-jet propulsion device with the following technical result: increasing the manufacturability of the design, maintainability and ease of maintenance, ensuring the possibility of interchangeability of individual blades of the straightener apparatus without labor-intensive operations and specialized equipment.

The said technical result is achieved by the fact that in a water jet propulsion device consisting of an impeller housing, which is attached to the water channel of a vessel, an impeller is placed in the housing, which is connected by a splined connection to a drive shaft for transmitting torque from the vessel's engine, and is installed by a threaded connection on the propeller shaft, according to the invention, the propeller shaft is installed in a cup by means of bearing supports, sealing units and a fairing cone with a sealing ring, a cover is also installed here, which takes up axial loads during the operation of the water jet propulsion device, the blades of the straightening apparatus are installed on the cup, resting from the front, in the direction of fluid movement, side against the impeller housing and pulled together by a nozzle and a curtain on the other side to the impeller housing, then a replaceable ring nozzle is installed on the nozzle, a rod for controlling the rotary nozzle is installed on the curtain and a valve of the reversing device is fixed.

The essence of the invention is explained by drawings, where Fig. 1 shows a general view of a water jet propulsion device; Fig. 2 shows variants of the execution of a sector division of a straightening apparatus with 5 (Fig. 2a), 7 (Fig. 2b) and 9 (Fig. 2c) blades.

The water jet propulsion unit comprises a housing 1 housing an impeller 2 connected via a threaded joint to a propeller shaft 3 and a splined joint to a drive shaft 4. Bearings, seals, and the necessary rings are mounted on the shaft 3 and housed in a cup 5. The cup 5 provides a stop for the blades of the straightener apparatus 6 along the flange (A). A cover 7 is installed in the cup to accommodate the resulting axial loads. The straightener apparatus 6 consists of sectional blades (a set of sections may consist of a different number of blades, from 3 to 9 pieces); during assembly, it rests against the housing 1 of the impeller with its surface (B). Fixation is ensured by pressing the nozzle 8, curtain 9, and a bolted connection, as well as a threaded connection of the fairing 10 and surfaces (B) and (G). The nozzle 8 is made with a replaceable ring attachment 11 installed in it. The rotary nozzle 12 is controlled by a rod 13, installed by means of fastening elements on the curtain 9, on which the valve of the reversing device 14 is also fixed.

The propulsion unit operates as follows. Torque is transmitted to impeller 2 via drive shaft 4, forcing fluid from the vessel's water intake through the flow path of impeller 2 and blades 15 of straightener 6 into nozzle 8 with replaceable ring attachment 11. Smooth contours of the flow path of the water-jet propulsion unit minimize losses, and a narrowing of the cross-section at the outlet of straightener 6 compresses the jet and increases the velocity of the jet from nozzle 8. Replaceable ring attachment 11 allows for adjustment of the cross-sectional area at the outlet of nozzle 8 to fine-tune the operation of the water-jet propulsion unit with varying engine powers.

When operating a small vessel, foreign objects may enter the flow path of the waterjet propulsion system. Foreign objects entering the flow path can damage one or more guide vane blades. Operating a waterjet with improper geometry and damaged guide vane blades significantly reduces the propulsion system's efficiency, which can lead to a disruption in the operating modes of the engine and propulsion system, leading to premature failure.

Dividing the outflow guide vane into sectors allows, during operation, in the event of failure of one or more outflow guide vane blades, to replace only the damaged sectors, rather than the entire unit. Replacing damaged sectors does not require specialized equipment or facilities, nor does it require complete disassembly of the waterjet propulsion unit, ensuring efficient and less labor-intensive repairs during vessel operation.

The sector-based division of the straightener reduces the labor intensity of finishing the straightener blade surfaces and allows for varying the number of straightener blades when fine-tuning the propulsion system with a wider engine power range. Varying the number of straightener blades allows for optimization of the jet propulsion system to suit the engine's characteristics, as well as increasing the overall efficiency of the jet propulsion system by selecting the optimal number of blades and the geometry of the straightener's flow path.

Claims (1)

A water jet propulsion unit comprising a housing in which an impeller is placed, connected by a splined joint to a drive shaft for transmitting torque from a vessel's engine and installed by a threaded joint on a propeller shaft, characterized in that the propeller shaft is installed in a cup by means of bearing supports, sealing units and a fairing cone with a sealing ring, a cover is also installed here that takes up axial loads during operation of the water jet propulsion unit, straightening apparatus blades are installed on the cup, resting from the front side, in the direction of fluid movement, against the impeller housing and pulled together by a nozzle and a curtain on the other side to the impeller housing, a replaceable annular attachment is installed on the nozzle, and a rod for controlling a rotary nozzle is installed on the curtain and a reversing device flap is secured.