GB2217759A

GB2217759A - A sluice radial gate have buoyant chamber to assist raising of gate

Info

Publication number: GB2217759A
Application number: GB8806151A
Authority: GB
Inventors: John Russell Self
Original assignee: BICC PLC
Current assignee: Balfour Beatty PLC
Priority date: 1988-03-15
Filing date: 1988-03-15
Publication date: 1989-11-01
Also published as: GB8806151D0

Abstract

A radial gate suitable for use in a sluice extending through a caisson or other fixed structure or suitable for use in a navigation lock has on its concave side at least one fluid-tight chamber which is uniformly positioned with respect to the upstanding boundary edges of the gate in such a position that the chamber is fully immersed in water when the gate is in its lowered position. The chamber contains air or other material that will render the chamber buoyant. The chamber has a wall or walls of such a shape that the hydraulic forces acting on the gate from each of its sides still pass through or immediate adjacent to the pivotal axis of the gate. The power required to raise the gate from its closed position is less than that to raise a radial gate of corresponding size and construction which does not have a buoyant chamber. <IMAGE>

Description

AN IMPROVED RADIAL GATE This invention relates to gates for use in a submerged or partially submerged situation in an estuary, river, canal or other waterway for controlling flow of water between, and/or the level of water on, opposite sides of the gates and is particularly concerned with a gate for this purpose generally known as a radial gate.

A radial gate comprises a substantially smoothly curved wall which extends across the full width of the waterway through which the flow of water is to be controlled and whose centres of curvature lie on a substantially horizontal axis extending transversely of the waterway, the smoothly curved wall being pivotally mounted about said axis so that by appropriate pivotal movement of the wall about said axis the radial gate can be raised or lowered to permit or prevent or to control flow of water from one side of the gate to the other.

Generally, the smoothly curved wall is in the form of a substantially water-tight skin plate which is carried by a framework of beams and stiffening members, the assembly being proportioned having respect to the width and depth of the waterway which the radial gate is to close and the magnitude of the loads to which the radial gate will be subjected when in service. The radial gate has extending from each of its upstanding boundary edges in an approximately radial direction with respect to the skin plate support arms pivotally mounted on a pivot smoothly curved bearing assembly supported alongside the waterway. Raising or lowering of the radial gate is effected by hydraulic hoists or other means connected to the support arms extending from each boundary edge of the gate.A radial gate of this construction will hereinafter, for convenience, be referred to as "a radial gate of the kind described".

In order to ensure that the pivot bearing assemblies and pairs of radially extending support arms of a radial gate of the kind described will be clear of the waterway when the radial gate is pivoted upwardly to a sufficient extent for the gate to be fully open, for a gate having a depth of D, the smoothly curved skin plate of the gate will have to have a radius of at least 1.5D.

Where, for example, a radial gate is to have a depth of 15 metres, substantial power would be required to open the gate.

It is an object of the present invention to provide an improved radial gate of the kind described in which the power required to raise the gate as compared with that required for a known form of radial gate of the kind described of corresponding shape and size is substantially reduced.

According to the invention, the improved radial gate has on its concave side at least one substantially fluid-tight chamber which is uniformly positioned with respect to the upstanding boundary edges of the gate in such a position that the chamber is fully immersed in water when the gate is in its lowered position, which contains air or other material that will render the chamber buoyant, and which has a wall or walls of such a shape that the hydraulic forces acting on the gate from each of its sides still pass through or immediately adjacent to the pivotal axis of the gate.

The provision of one or more than one-fluid-tight buoyancy chamber so reduces the effective submerged weight of the gate that the power required to raise the gate from its closed position is substantially less than that required to raise a radial gate of corresponding size and construction which does not have a buoyancy chamber or buoyancy chambers.

Preferably, the buoyancy chamber or chambers is or are of such a size and buoyancy that the effective submerged weight of the radial gate is reduced to that required to effect and maintain positive closure against the most severe conditions anticipated when the gate is in service.

In a preferred embodiment, the improved radial gate has a plurality of buoyancy chambers, each independent of the other or others.

The or each buoyancy chamber may be separately formed with respect to the water-tight skin plate and framework of beams and stiffening members of the improved radial gate and permanently or detachably secured to the framework, or the water-tight skin plate of the gate may constitute a wall of the buoyancy chamber or of each of at least some of the buoyancy chambers which will then be a component part of the gate.

Where the skin-plate constitutes a wall of the or a buoyancy chamber, preferably the wall of the buoyancy chamber remote from the skin plate, i.e. the opposite wall of the chamber, is smoothly curved with its centres of curvature lying on or immediately adjacent the transversely extending horizontal pivotal axis of the gate and each wall of the chamber extending from said opposite wall of the chamber towards the skin plate lies in a substantially vertical plane substantially normal to the pivotal axis of the gate.

Preferably, the support arms at each side of the waterway have on the side of the support arms nearer the waterway and extending between the arms a substantially smooth surface and, in a preferred embodiment, the support arms at each side are positioned in a recess in the side wall of the waterway so that said substantially smooth surface lies in approximately the same plane as the general surface of the adjacent side wall of the waterway.

The improved radial gate of the present invention may be used in a waterway where flow of water from one side of the gate to the other is permitted by causing the gate to pivot in such a way that the gate is raised upwardly above the waterway so that water initially flows from one side of the gate to the other under the lowermost edge of the gate. One particular waterway of this kind for which the improved radial gate is especially suitable is a sluice extending through a fixed structure, e.g. a5.caisson, so that, when the radial gate is being opened, it pivots upwardly through an opening in the roof of the sluice and, when it is in the fully-opened position, constitutes a part of the roof of the sluice.

The improved radial gate of the present invention may also be used in a waterway where it is preferred for initial flow of water from one side of the gate to the other to be above the uppermost edge of the gate, that is to say in a waterway where the radial gate is opened by causing the gate to pivot downwardly into a recess formed in the bed of the waterway. One particular waterway of this kind for which the improved radial gate is suitable is a navigation lock.

The invention is further illustrated, by way of example, by the accompanying informal drawing which shows a longitudinal sectional view through a sluice in a caisson which is to be closed by a preferred radial gate having buoyancy chambers.

The improved radial gate of the present invention has all the advantages of known radial gates of the kind described.

Claims

Claims:

1. A radial gate of the kind described for use in an estuary, river, canal or other waterway, which radial gate has on its concave side at least one substantially fluid-tight chamber which is uniformly positioned with respect to the upstanding boundary edges of the gate in such a position that the chamber is fully immersed in water when the gate is in its lowered position, which contains air or other material that will render the chamber buoyant, and which has a wall or walls of such a shape that the hydraulic forces acting on the gate from each of its sides still pass through or immediately adjacent to the pivotal axis of the gate.

2. A radial gate as claimed in Claim 1, wherein the buoyancy chamber or chambers is or are of such a size and buoyancy that the effective submerged weight of the radial gate is reduced to that required to effect and maintain positive closure against the most severe conditions anticipated when the gate is in service.

3. A radial gate as claimed in Claim 1 or 2, wherein the radial gate has a plurality of buoyancy chambers, each independent of the other or others.

4. A radial gate as claimed in any one of the preceding Claims, wherein the or each buoyancy chamber is separately formed with respect to the water-tight skin plate and framework of beams and stiffening members of the radial gate and is permanently or detachably secured to the framework.

5. A radial gate as claimed in any one of Claims 1 to 3, wherein the water-tight skin plate of the gate constitutes a wall of the buoyancy chamber or of each of at least some of the buoyancy chambers which will then be a component part of the gate.

6. A radial gate as claimed in Claim 5, wherein the wall of the or a buoyancy chamber remote from the skin plate is smoothly curved with its centres of curvature lying on or immediately adjacent the transversely extending horizontal pivotal axis of the gate, each side wall of the chamber extending from said remote wall of the chamber towards the skin plate lies in a substantially vertical plane substantially normal to the pivotal axis of the gate, and upper and lower walls of the chamber each lie in a plane containing the pivotal axis of the gate and substantially normal to the skin plate.

7. A radial gate as claimed in any one of the preceding Claims, wherein the support arms at each side of the waterway have on the side of the support arms nearer the waterway and extending between the arms a substantially smooth surface.

8. A radial gate as claimed in Claim 7, wherein the support arms at each side are positioned in a recess in the side wall of the waterway so that said substantially smooth surface lies in approximately the same plane as the general surface of the adjacent side wall of the waterway.

9. A radial gate of the kind described substantially as illustrated in the accompanying informal drawing.