GB2289912A

GB2289912A - Underwater excavation or marine vehicle propulsion apparatus

Info

Publication number: GB2289912A
Application number: GB9514359A
Authority: GB
Inventors: Nicholas Victor Sills
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-07-13
Filing date: 1995-07-13
Publication date: 1995-12-06
Anticipated expiration: 2015-07-13
Also published as: GB2289912B; GB9514359D0

Abstract

An underwater soil excavation apparatus or a marine vehicle propulsion apparatus comprising a tube 11 in which a propeller 17 is mounted for rotation. A circumferential disc mounted variable geometry piston drive 21 is mounted to the tips of the propeller blades and protrudes into and is enclosed by a circular chamber 25 around the outer periphery of the tube. Water pumped into the circular chamber opens hinged vanes 26 that form pistons in the chamber and cause the propeller to rotate and thereby draw water through the tube from an inlet at one end to an outlet at the other. The apparatus is particularly useful for excavating holes and trenches in the seabed and uncovering buried structures in the seabed. When mounted on a submerged vehicle or stucture the apparatus can be used to propel or orientate the object. <IMAGE>

Description

UNDERWATER EXCAVATION AND MARINE VEHICLE PROPULSION APPARATUS This invention relates to an undenvater soil excavation apparatus when operated in a vertical orientation close to the seabed or to a marine vehicle propulsion apparatus when operated in any orientation attached to a floating or submerged vehicle or object.

Undenvater excavation apparatus using the wash from a ship's propeller deflected vertically downwards through an angled tube toward the seabed, to dig holes if stationary or trenches if moving, are well known in the marine salvage and dredging industries and commonly called propwashes. However these apparatus are only useful in shallow water due to the dissipation of the wash in deep water.

Remote forms of the apparatus with propellers powered by hydraulic or electric motors (EPC No 0289520) and by water jets mounted on the propeller in the manner of a reaction turbine (UK Patent No 2240568) have been developed to overcome the shallow water limitation and are lowered and operated close to the seabed. Both of these devices have severe operational and efficiency problems due to their drive mechanisms.

This invention provides an undenvater excavation or propulsion apparatus comprising a hollow tube having an inlet to receive water. an outlet for discharge of water, a propeller mounted for rotation in the hollow tube to draw water through the inlet and deliver a stream of water through the outlet and a circumferential disc (or sleeve) mounted variable geometry piston drive means and means to supply water under pressure to the drive means to cause the propeller to rotate and deliver a flow of water through the outlet for displacing materials on the seabed or developing thrust to propel a marine vehicle with greatly improved efficiency.

The following is a description of some of the specific embodiments of the invention reference being to the accompanying drawings in which Figure 1 is a longitudinal section through an undenvater excavation or marine vehicle propulsion apparatus.

Figure 2 is a transverse section on the line of2-2 of figure 1.

Figure 3 is a horizontal section on the line of 3-3 of figure 2.

Figure 4 is a longitudinal section through an alternative form of an undenvater excavation or marine vehicle propulsion apparatus.

Figure 5 is a transverse section on the line of 44 of figure 4.

Figure 6 illustrates the operation of the circumferential disc mounted piston vanes during one cycle.

Figure 7 illustrates the operation of the an alternative circumferential sleeve mounted piston vanes during one cycle.

The drawings illustrate an undenvater excavation and marine vehicle propulsion apparatus comprising a hollow cylindrical tube 11 having an inlet end 12 through which water can be drawn into the tube and an outlet end 13 from which water may be discharged from the tube.

A bearing housing 14 is mounted along the axis of the tube on a set of vanes 15. which extend radially between the housing and the inner periphery of the hollow cvlindrical tube.

A shaft 16 extends from the bearing housing and is mounted for rotation of the propeller indicated at 17. The propeller comprises a boss 18 secured to the shaft by a threaded nut 19 and two (or more) outwardly extending blades 20. In figures 1 and 3, a disc 21 encircles and is secured to the tips 22 ofthe blades. The disc protrudes through a narrow annular slit 23 which is formed in the cylindrical tube and which encircles the outer perisher perscribed by the propeller.

A hollow ring 24 is fixed to the outside periphery of the cylindrical tube either side of the annular slit so that a circumferential chamber 25 is formed that encloses the disc. The ring 24 also holds the two halves of the apparatus, formed by the annular slit, together.

The disc 21 has inset into its upper and lower surface a set (or sets) of hinged vanes 26.

The vanes on the upper and lower surfaces are articulated to open until they rest against restraints in a perpendicular position as more clearly seen in figure 6. The vanes are shaped so that when they are fully open a piston is formed within the chamber. When the vanes are fully closed they lie flush with the disc surface in recesses 27 more clearly seen in figures 2 and 3 and do not form a piston.

As indicated in figure 1 at 28 and more clearly seen in figure 3, incorporated into and set across the circumferential chamber are one (or more) fixed barrier(s) that completely occlude the bore of the chamber except for a slit 29 through which the disc passes. The barrier slit is occluded by the disc which reduces to a minimum the loss of water through the barrier slit from the upstream or pressurised side of the circumferential chamber to the downstream or unpressurised side of the circumferential chamber as described later.

On one side or upstream of the barrier is a water inlet port(s) 30 for the introduction of pressurised water into the circumferential chamber.

On the other side or downstream of the barrier is a water outlet port 31 for the exhaust of spent water from the circumferential chamber more clearly seen in figure 3.

The disc 21, that protrudes through the annular slit 23 in the hollow cvlindrical tube is a close fit and reduces to a minimum the loss of pressurised water from the circumferential chamber through the annular slit when the chamber is pressurised.

On the downstream or water outlet port(s) side of the barrier are two (or more) vane closure cams 32. The cams extend from the upper and lower internal wall of the circumferential chamber to the upper and lower edges ofthe barrier slit 29.

With reference to figure 6 a sequence of events will now be described that will make the operation of the disc mounted variable geometry piston apparatus apparent.

A pressurised water supply is pumped from the surface through a flexible or rigid pipe fixed to the apparatus such that when pressurised water enters the apparatus through inlet port 30 the propeller is made to rotate.

The apparatus is always operated submerged in water with all spaces flooded with water.

The shape of each vane and the shape of each recess 27 in the upper and lower surfaces of the disc is such that when the vane is in the closed position there is a cavity under the trailing edge ofthe vane as best seen at 27 of figures 2 and 3. The orientation ofthe water inlet port(s) 30 to the disc surfaces is such that when water enters the circumferential chamber through port(s) 30 it will flow into the cavity. under the closed vane and lift the vane into a perpendicular position as seen at 33 in figure 6 When both the vanes on the upper and lower disc surface are open they completely occlude the chamber bore in the manner of a piston.

When the pressure of water introduced into the chamber at 30 and acting on the piston vanes 33 rises above the resistance of the propeller, associated shaft bearings and disc, water will flow into the chamber and push the piston in the direction of arrow 34 of figures 2 and 6 and start to rotate the disc and the propeller attached to it.

In figure 6 as the piston travels around the circumferential chamber it will encounter the water outlet port(s) 31 on the downstream side of the chamber barrier. When the piston passes the outlet port the pressurised water driving the piston will exhaust through outlet port. The release of pressure from the piston vanes will allow the vane closure cams 32 to close the vanes into their recesses prior to passing through the barrier slit 29. Once through the barrier the piston vanes reopen and another cycle starts.

With reference to figures 4, 5 and 7 an alternative form of the apparatus will now be described. The disc 21 of figures 1 to 3 and 6 is replaced within the circumferential chamber with an annular sleeve 40. The sleeve 40 rotates close to the outer periphery of the hollow tube 11 and inside the circumferential chamber 25. The sleeve has inset into the outer surface a hinged vane(s) 41. The vane is articulated to open until it rests against a restraint in a perpendicular position as more clearly seen at 52 in figure 7. The vane is shaped so that when in the fully open position a piston is formed within the chamber.

When the vane is fully closed it lies flush with the sleeve surface in recess 42 as seen in figures 5 and 7 and does not form a piston.

In figures 4. 5 and 7 incorporated into and set across the circumferential chamber are one (or more) fixed barrier(s) 43 that completelv occlude the bore of the chamber except for a slit 44 through which the sleeve passes. The barrier slit is occluded bx the sleeve which reduces to a minimum the loss of water through the bamer sllt ttom the upstream or pressurised side of the circumferential chamber to the downstream or unpressurised side of the circumferential chamber as described later.

On one side or upstream ofthe barrier is a water inlet port(s) 45 for the introduction of pressurised water into the circumferential chamber.

On the other side or downstream side of the barrier is a water outlet port 47 for the exhaust of spent water from the circumferential chamber more clearly seen in figure 7.

In figure 4 a ring 49 is fixed to the ends of the propeller blade tips and protrudes through the annular slit 23 formed in the hollow tube and is secured to the sleeve 40 as seen at 50 in figure 7. The ring is a close fit within the annular slit and reduces to the minimum the loss of pressurised water from the circumferential chamber through the slit when the chamber is pressurised.

On the downstream or water outlet port side ofthe barrier is a vane closure cam 48. The cam extends from the outer wall ofthe circumferential chamber to the edge ofthe barrier slit 44.

With reference to figure 7 a sequence of events will now be described that will make the operation of the sleeve mounted variable geometry piston alternative form ofthe apparatus apparent.

A pressurised water supply is pumped from the surface through a rigid or flexible pipe fixed to the apparatus such that when pressurised water enters the apparatus through inlet port 45 the propeller is made to rotate.

The apparatus is always operated submerged in water uith all spaces flooded with water.

The shape of the vane(s) and the shape of recess(s) in the sleeve as indicated at 51 of figure 7, is such that when the vane is in the closed position there is a cavity under the trailing edge of the vane . The orientation of the water inlet port 45 to the sleeve surface is such that when water enters the circumferential chamber through the inlet port 45 it will flow into the cavity under the closed vane and lift it into a perpendicular position as seen at 52. When the vane is fully open it completely occludes the chamber bore in the manner of a piston.

When the pressure and flow of water introduced into the chamber, at inlet port 45 and acting on the piston 52, rises above the resistance ofthe propeller, associated shaft bearings and sleeve, the piston will travel in the direction of arrow 46 and start to rotate the sleeve and propeller attached to it.

As the piston passes the water outlet port 47 of figures 5 and 7 the flow and pressure of water will fall and allow the vane closure cam 48 to close the vane prior to passing through the narrow barrier slit 44.

Referring now to figure 8 of the drawings there is shown an application of the excavation apparatus of figures 1 - 7 to remove seabed materials whilst being manoeuvred horizontally from a surface vessel to excavate a trench.

Referring now to figure 9 of the drawings there is shown an application of the marine propulsion apparatus fixed to a submerged vehicle for the purpose of propelling or manoeuvring.

Claims

1. This invention provides an underwater excavation or propulsion apparatus comprising a hollow tube having an inlet to receive water, an outlet for discharge of water, a propeller mounted for rotation in the hollow tube to draw water through the inlet and deliver a stream of water through the outlet and a circumferential disc (or sleeve) mounted variable geometry piston drive means and means to supply water under pressure to the drive means to cause the propeller to rotate and deliver a flow of water through the outlet for displacing materials on the seabed or developing thrust to propel a marine vehicle with greatly improved efficiency.

2. An underwater excavation apparatus as claimed in claim 1, wherein the circumferential disc (or annular sleeve in an alternative form ofthe apparatus) mounted variable geometry piston drive means is secured to the blade tips of the propeller.

3. An underwater excavation apparatus as claimed in claim 1 or claim 2 wherein hinged piston vanes forming part of the variable geometry piston drive means are closed when inset flush into recesses in the surface of the disc (or annular sleeve in an alternative form of the apparatus) and do not form a piston(s).

4. An undenvater excavation apparatus as claimed in claims 1 to 3 wherein the hinged vanes forming part of the variable geometry piston drive means are open when perpendicular to the disc or annular sleeve surface and form a piston.

5. An undenvater excavation apparatus as claimed in claims 1 to 4 wherein a disc or sleeve mounted variable geometry piston drive means is enclosed in a circumferential chamber means formed around the outside periphery of the hollow tube.

6. An underwater excavation apparatus as claimed in claims 1 to 5 wherein the hollow tube has a slit encircling the periphery of the propeller through which the disc (or a sleeve support ring in an alternative form ofthe apparatus) protrudes into the circumferential chamber.

7. An underwater excavation apparatus as claimed in claims 1 to 6 wherein a barrier means across the circumferential chamber completely occludes the bore of the chamber except for a slit through which the disc or sleeve passes and prevents free circulation of water around the chamber.

8. An underwater excavation apparatus as claimed in claims 1 to 7 wherein a piston vane closure cam (or cams) extends at a sloping angle from the wall of the circumferential chamber to the edge(s) of the barrier slit.

9. An underwater excavation apparatus as claimed in claims 1 to 8 wherein the surfaces of the disc or sleeve support ring (in an alternative form of the apparatus) protruding through the slit encircling the hollow tube form a close tolerance fit such that the loss of pressurised water from the circumferential chamber between the edges of the slit and the surfaces of the disc or sleeve support ring is reduced to the minimum.

10. An undenvater excavation apparatus as claimed in claims I to 9 wherein a piston vane recess means in the surface of the disc or sleeve is shaped so that a cavity is formed under a closed piston vane.

11. An underwater excavation apparatus as claimed in claims ] to 10 wherein the piston vane(s) is shaped such that when in a closed position in a recess and exposed to a flow of water on its trailing edge, bx wax of example, when passing a water inlet port. indage will force open the vane.

12. An underwater excavation apparatus as claimed in claims 1 to 11 wherein an inlet port means is mounted on the upstream side of the barrier means at an angle such that when water under pressure is feed to the inlet port water water will enter the circumferential chamber and impinge at an angle on the surface of the disc or sleeve.

13. An underwater excavation apparatus as claimed in claims 1 to 12 wherein an outlet port means is mounted on the downstream side of the barrier means such that when water under pressure is feed to the inlet port means it travels around the circumferential chamber means and is exhausted through the outlet port means.

14. An underwater excavation apparatus as claimed in claims 1 to 13 wherein a mechanical stop means is present in the piston vane(s) recess to prevent the piston vane opening further than perpendicular to the surface of the circumferencial disc or sleeve.

15. An underwater excavation apparatus as claimed in claims 1 to 14 wherein if the apparatus is mounted on a floating or submerged vehicle or object can be used to propel the vehicle or object through the water.