WO1990010790A1

WO1990010790A1 - Fluid flow systems

Info

Publication number: WO1990010790A1
Application number: PCT/GB1990/000366
Authority: WO
Inventors: John Herbert Sulman
Original assignee: Individual
Current assignee: Individual
Priority date: 1989-03-09
Filing date: 1990-03-09
Publication date: 1990-09-20
Anticipated expiration: 1991-09-09
Also published as: GB8905451D0; AU5182090A

Abstract

An e.g. electrical generating system comprises a pipe (D) laid to extend generally in a North-South direction with means (C) for introducing sea water into the higher-latitude end of the pipe. Flow of water is promoted through the pipe towards the lower-latitude end, where an electric generator turbine (T) is driven by the flow of water.

Description

Fluid Flow Systems

This invention relates to fluid flow systems and more particularly to systems for promoting the flow of fluid through a duct, which flow may be used for example to drive an electrical generator, effect suction dredging or effect pumping.

Various hydro-electrical systems are known for generating electricity and these depend upon being able to make use of an existing flow of water or upon building a dam to contain a reservoir of water which provides a head of pressure: then a controlled flow of water is permitted from this reservoir or head, to drive turbines which in turn drive electrical generators. However, such hydro¬ electric plants are extremely expensive to build and usually adversely affect the environment.

I have observed that if a pipe is laid running from North to South on the surface of the earth, then if in the northern hemisphere water is fed into the northern end of the pipe, it will flow through the pipe and out of its southern end. This phenomenon is due to rotation of the earth around its north-south axis and to the consequent forces acting on the water in the pipe.

In accordance with this invention, there is provided an electricity generating system, comprising a pipe laid to extend generally in a North-South direction, means for introducing liquid into the higher-latitude end of the pipe and an electrical generator disposed at the lower latitude end of the pipe and arranged to be driven by the liquid which flows along the pipe owing to forces acting due to rotation of the earth on its axis.

The pipe is preferably laid on the sea bed in a suitable location. Such an installation can be made virtually invisible in its environment, providing continuous uninte rupted source of power at a cost considerably less than for a tidal barrage of equivalent intermittent power output.

A series of turbo-generators may be situated at intervals along the length of a single pipe.

The flow of water may be stopped by diverting it into a water tower to create an opposing back pressure. Also in accordance with this invention, there is provided a suction dredging system, comprising a pipe laid to extend generally in a North-South direction, with its higher- latitude end disposed at a depth below water, and its lower-latitude end arranged to discharge therefrom water and any material drawn into the pipe at its higher latitude end.

Further in accordance with this invention, there is provided a pumping system, comprising a pipe laid to extend generally in a North-South direction, with its higher-latitude end disposed below water and its lower- latitude end disposed at higher vertical level and arranged to discharge water drawn into the pipe at its higher_latitude end.

Such a pumping system may be used for irrigation or for returning water from a lower level to a higher level in canals.

Embodiments of this invention will now be described by way of example only and with reference to the accompanying drawings, in which:

FIGURE 1 is a diagrammatic plan of an electrical generator system in accordance with the invention;

FIGURE 2 is a diagrammatic elevational view of the electrical generator system;

FIGURE 3 is a diagrammatic view of a turbine in the pipe in the electricity generating system of Figures 1 FIGURE 4 is a diagrammatic plan of a suction dredging system in accordance with the invention; and

FIGURE 5 is a diagrammatic elevational view of a pumping system in accordance with the invention.

Referring to Figures 1 and 2 of the drawings there is shown an electricity generating system which comprises an enclosed pipe or duct D laid underwater to extend generally North and South. The duct can follow any convenient path so long as it ends H,L are at different latitudes.

A conical inlet C is provided at the higher latitude end H of the duct D where the inflow accelerates from rest to the speed of flow in the duct. This flow speed remains constant over the length of the duct, given a constant cross sectional area: the longer the duct, the faster the flow. The inlet C is sited at a depth d below the surface of the water. A turbo-generator T is situated at the lower latitude or outlet end L of the duct.

Forces due to the earth's rotation cause deep ocean currents to flow in an equatorial direction in temperate latitudes. The peripheral speed of the earth's surface increases towards tropical latitudes requiring the body of water to be accelerated eastwards, failing which it adopts a westward drift, losing momentum, and eventually returning in a polar direction as a surface current.

I have observed that under a combination of these forces, water constrained in an open-ended duct laid over the sea bed in a suitable coastal location with appropriate orientation develops a rate of flow proportionate to the length of time it is subjected to the forces and therefore propor ionate to the length of the duct. Sites can be identified around the coasts of the UK and Europe where it is feasible to generate significant amounts of electrical power through turbo generators driven by the flow of seawater in such ducts. In the system shown in Figures 1 and 2, a hydrostatic balance is achieved between the two ends of the duct, with the inlet end H situated at a depth d below the surface similar to the head of water pressure developed at the outlet end. In other words, the pressure of water at the inlet and outlet ends is substantially the same. This ensures that all of the power in the flow is available to drive the turbine and none is used in drawing the water into the duct.

The lower latitude or outlet end L may be situated on land or on some marine structure where the turbine TT is driven by the water issuing from it, and the turbine drives an electrical generator G. The water is then discharged back to the sea at a point R below sea level in order to minimise loss of power from back pressure.

A water tower T is provided at the site of the outlet end or at intermediate points, into which the flow may be diverted by the operation of a valve V to create a back pressure sufficient to stop the flow completely should this become necessary. The height h of the tower should not be less than the head of water pressure at that point developed by the water flow.

In addition to or instead of the terminal turbine T, smaller axial or in-line turbo-generators e.g. Tl, T2 may be incorporated in the duct at intervals along its length, up to the limit of the generating capacity of the duct and allowing a supply of electricity to underwater installations.

Preferably the or each turbine comprises a variable-pitch axial-flow turbine, thus allowing a restriction in the rate of flow in the pipe, minimising power loss through turbulence whilst speeding the flow through the turbine. As shown in Figure 3, a pod arrangement may be used, the pod being shown at P and the turbine at T. Further, a sliding venturi-shaped annulus SV may be provided within the duct D, which can be slid into engagement with the pod P and uncover ports 0 in the duct wall to divert the flow from the turbine.

Figure 4 shows iagram atically a suction dredging system in v/hich a pipe D is laid to extend generally in a North-South direction, with its higher- latitude end disposed at a depth below sea water, and its lower-latitude end arranged to discharge into deep water the material drawn into the pipe at its higher-latitude end with perforations 0 through which water-borne sand and silt to be dredged (e.g. from channels or harbours) pass into the pipe. The pipe D is designed to have a fast, turbulent flow to keep the spoil suspended in the water as it flows through the pipe.

Figure 5 shows a pumping system in a canal which has successive stretches at different levels with intervening locks LK. A pipe D extends in generally North- South direction from a lower level to a higher level. In accordance with this invention, a flow of water is promoted through the pipe D from the ends at lower level to the end at higher level. Preferably the pipe D progressively reduces in cross-section to gain further height, at the expense of volume of flow.

Claims

1) An electricity generating system, comprising a pipe laid to extend generally in a^'ϊϊorth-South direction, means for introducing liquid into the higher-latitude end of the pipe and an electrical generator disposed at the lower latitude end of the pipe and arranged to be driven by the liquid which flows along the pipe owing to forces acting due to rotation of the earth on its axis.

2) An electricity generating system as claimed in claim 1, in which the pipe is laid on the sea bed.

3) An elecricity generating system as claimed in claim 1 or 2, in which a series of turbo-generators are situated at intervals along the length of the pipe.

4) A suction dredging system, comprising a pipe laid to extend generally in a North-South direction, with its highr-latitude end arranged to discharge therefrom water and any material drawn into the pipe at its higher latitude end.

5) A pumping system, comprising a pipe laid to extend generally in a North-South direction, with its higher-latitude end disposed below water and its lower- latitude end disposed at a higher vertical level and arranged to discharge water drawn into the pipe at its higher-latitude end.