GB2143923A

GB2143923A - High pressure chambers

Info

Publication number: GB2143923A
Application number: GB08320346A
Authority: GB
Inventors: Reginald Edwin Downton Burrow
Original assignee: Taylor Woodrow Construction Ltd
Current assignee: Taylor Woodrow Construction Ltd
Priority date: 1983-07-28
Filing date: 1983-07-28
Publication date: 1985-02-20
Also published as: GB2143923B; IT8422040A0; IT1176473B; GB8320346D0

Abstract

A high pressure chamber, for example for simulating conditions in deep ocean, comprises a cylinder (6) within which there is the hollow interior (4), of the chamber, and a closure member (24) for closing an opening of the chamber interior, the chamber further comprising locking elements (26) which are movable between a release position, in which they are disposed outwards of the periphery of the closure member (24) to allow the closure member (24) to be removed from the opening, and a locking position, in which they engage edge regions of the closure member (24) to prevent removal of the closure member (24) from the opening, the locking elements (26 or 42) being operable by control members (32) which extend through the wall (6) to actuating means (30) disposed at or adjacent the exterior of the cylinder (6). In this high pressure chamber, because the locking elements, which may be additional to or part of the control members, are operated from the exterior of the cylinder, neither the locking elements themselves nor the actuating means obstruct access to the hollow interior of the chamber when the closure member is removed. <IMAGE>

Description

SPECIFICATION Containers This invention relates to containers and particularly, although not exclusively, to containers such as high pressure chambers.

High pressure chambers may be used, for example, for simulating conditions in deep ocean, the chamber being filled with water and pressurised so that items supported from a closure member that is at one end of the chamber can be subjected to the water pressure within the chamber for test purposes.

Such a chamber can have, for example, an inside diameter of 3m, an internal length of at least 4m, and a maximum operating pressure of 600 bar. The pressurisation rate can be 200 bar per minute.

In a known high pressure chamber, a closure comprises a closure member and a series of struts which are deployed using hydraulic rams to bear on inclined surfaces on the exterior side of the closure member. This system is expensive and potentially vulnerable to any accidental depressurisation of the chamber. In addition, the hydraulic equipment and mechanical fitments required to operate the closure leave very little space at the centre of the closure through which access can be obtained to the chamber.

Another known closure system uses a series of part-annular keys. When the chamber is closed, the keys engage the edges of the closure member and project into a groove formed in the wall of the chamber. The keys are locked in place by small retaining wedges.

To enable the closure member to be removed, the retaining wedges are removed and the keys are retracted inwardly to be stored on the outer surface of the closure member. Bearing in mind that, in a large pressure chamber, the keys would comprise heavy steel components, heavy manipulating gear is required to move the keys to and fro on the surface of the closure member, and again very little space is left for penetrations or for experimental equipment which might need to be fitted externally on the closure member. A further disadvantage is that loads are transferred from the edge of the closure member to the wall in a rather indeterminate way.When the chamber is under pressure, the keys are in direct shear, and there is a tendency for them to rotate so that the load is transferred to the wall in a way which is dependent upon the precise fitting of the keys themselves and of the retaining wedges.

According to the present invention there is provided a container comprising a wall defining a chamber, and a closure member for closing an opening of the chamber, the container further comprising locking elements which are movable between a release position, in which they are disposed outwards of the periphery of the closure member to allow the closure member to be removed from the opening, and a locking position, in which they engage edge regions of the closure member to prevent removal of the closure member from the opening, the locking elements being operable by control members which extend through the wall to actuating means disposed at or adjacent the exterior of the wall.

Because the locking elements are operated from the exterior of the wall, neither the locking elements themselves nor the actuating means obstruct access to the chamber when the closure member is removed.

Each locking element and its control member may comprise a single component having substantially the same cross-sectional area across the entire wall of the chamber. However, in preferred embodiments, the locking elements comprise keys which are connected to the actuating means by relatively thin rods, constituting the control members, which extend through the wall of the chamber.

The movement of the locking element between the release position and the locking position may take place in directions parallel to the plane of the opening. However, in a preferred embodiment, the direction of movement of each locking element from the release position to the locking position is inclined to the plane of the opening such that each locking element moves towards a point on the centre line of the opening situated externally of the chamber.

The locking elements preferably occupy substantially the entire periphery of the closure member when in the locking position.

When in the release position, the locking elements may be accommodated within an annular groove provided in the wall of the chamber.

For a better understanding of the present invention, and to show how it may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 is a sectional view of a high pressure chamber; Figure 2 is a sectional view taken on the line Il-Il in Figure 1; Figure 3 is an enlarged view of part of the chamber of Figure 1; Figure 4 is a sectional view taken on the line IV-IV in Figure 3; Figure 5 is a sectional view corresponding to Figure 3 but showing an alternative construction; Figure 6 is a sectional view taken on the line VI-VI in Figure 5; Figure 7 is a sectional view corresponding to Figure 3, but showing a third alternative construction; and Figure 8 is a sectional view taken along the line VIII-VIII in Figure 7.

Referring first to Figure 1, the high pressure chamber comprises an inner steel cylinder 2, which partially defines a test space 4, and an outer concrete cylinder 6. The inner cylinder 2 is a composite structure, comprising a steel liner 8 with three shrunk-on steel hoops 10. A bottom closure plate 1 2 closes the bottom end of the inner cylinder 2, seals being provided to prevent leakage.

The outer cylinder 6 is axially pre-stressed by tendons 1 4 and circumferentially stressed by wire windings 1 6 in pre-cast concrete channels 18.

The outer cylinder 6 is supported by laminated rubber bearing pads on a castellated annular wall 20. A walkway 22 runs around the outer cylinder 6. It will be appreciated from the size of the walk-way 22 as indicated in Figure 1 that the installation as a whole is very large. To give a further indication of the size of the installation, the internal diameter of the inner cylinder 2 is 3m and the internal length is 4m.

The top end of the inner cylinder 2 is closed by a closure member in the form of a plug 24. The plug 24 is retained in the closed position by a series of part-annular locking elements or keys 26. These keys are slidable in an annular recess 28 formed in the outer cylinder 6. The keys 26 can be moved by hydraulic actuators 30 which act on the keys 26 through control rods 32 which extend through relatively thin tubes 33 cast into the outer cylinder 6.

The plug 24 is generally saucer-shaped and has a central opening 34 for the passage of, for example, power and other lines for operating and monitoring test equipment within the chamber 4 and for inserting and removing samples during testing. The plug 24 carries a sliding axial seal 36 for preventing leakage from the chamber 4 when under pressure.

The internal surface of the outer cylinder 6 above the plug 24 has a steel liner 38, the internal diameter of which is large enough to enable the plug 24 to be withdrawn entirely from the outer cylinder 6.

To carry out a test in the chamber 4, test equiment, for example models or samples, are fitted to the inside surface of the plug 24, and the plug 24 is then lowered through the liner 38 until it engages the top of the inner cylinder 2. The keys 26, which were previously retracted into the groove 28, as shown in dashed outline in Figure 4, are extended by the actuators 30 into contact with the outer edge region of the plug 24. The keys 26 then form a complete ring around the plug 24, and are positioned to transfer loads exerted on the plug 24, in the direction outwardly of the chamber 4, to the outer cylinder 6. Load spreaders 40 are embedded in the concrete of the outer cylinder 6 for receiving the load transferred from the plug 24 and distributing it in the material of the outer cylinder 6.

It will be appreciated that the load applied to the plug 24 as a result of pressure within the chamber 4 will place the keys 26 in direct compression. This is a consequence of the fact that the keys 26 are movable in directions inclined to the central axis of the opening which is closed by the plug 24, i.e.

inclined to the axis of the inner and outer cylinders 2 and 6. As shown in Figures and 3, the directions of travel of the keys 26 are inclined by approximateiy 60G to the central axis, the centre lines of the rods 32 lying in a conical surface the vertex of which lies on the central axis A at a position outside the chamber 4. In effect, the keys 28 form an annular extension of the plug 24 which engages the wall of the outer cylinder 6, at the groove 28, to prevent removal of the plug 24. In its closed position, the plug is located on a shoulder 29 constituted by an inturned flange of the liner 18.

Thus the keys 26 transfer load directly into the concrete of the outer cylinder 6. This provides a predictable mode of action with a simple form of closure. The actuating mechanism constituted by the hydraulic cylinders 30 is on the exterior of the installation, leaving clear space on the side of the plug 24 outside the chamber 4 and providing unobstructed access to the chamber 4 when the plug is removed.

The alternative construction of Figures 5 and 6 corresponds generally to that of Figures 1 to 4, and the same reference numerals are given to similar components. The principal difference between the embodiment of Figures 5 and 6 and that of Figures 1 to 4 is that, in Figures 5 and 6, the keys 26 are movable parallel to a plane perpendicular to the axis A of the cylinders 2 and 6. As a consequence, the keys 26 are placed in shear when the chamber 4 is pressurised, with the result that the transfer of load to the outer cylinder 6 takes place in an interdetermine and somewhat unpredicatable manner. Furthermore, the keys 26 tend to rotate under the influence of the moment applied to them by the plug 24. Nevertheless, the construction of Figure 5 has the advantage over the prior art that the space above the plug 24 is left clear for control and monitoring equipment, and removal of the plug 24 provides free access to the chamber 4.

The embodiment of Figures 7 and 8 generally corresponds to that of Figures 5 and 6, and again the same reference numerals are used to designate similar components. However, in the embodiment of Figures 7 and 8, each key 26 and its control rod 32 is replaced by a single very heavy beam 42 which extends through the wall of the outer cylinder 2 and is moved by actuators 30. The beam 42 has a replaceable bearing pad 44 for engagement with a peripheral flange 46 of the closure plug 24. In this embodiment, the plug 24 comprises a hemispherical member on which the peripheral flange is provided. Load spreaders 48 are provided to transfer to the outer cylinder 2 the couple applied to the beams 42 by the plug 24 when the chamber 4 is under pressure.

This embodiment retains the advantage that the area above the plug 24 is left clear for control and monitoring equipment and that free access to the chamber 4 can be obtained by removing the plug. Furthermore, the beams 44 are less likely than the keys 26 of Figures 5 and 6 to rotate when the chamber 4 is under pressure. However, the beams 44 are very heavy and require powerful actuators 30.

Figure 8 shows that two actuators are provided for each beam. Also, the beams 42 create discontinuities around the outer cylinder 6 and make it impossible to apply circumferential pre-stress to the outer cylinder 2 over the depth occupied by the beams. Another disadvantage, compared to the embodiments of Figures 1 to 6 is that the ends of the beams 42 engage only approximately half the available periphery of the plug 24, which results in very high contact stresses.

It will be appreciated that various changes can be made to the embodiments described without departing from the scope of the invention. For example, it is not essential for the actuators 30 to be hydraulic actuators; they could, instead, comprise other devices such as mechanical or electromechanical lead screws.

Furthermore, it is not essential for the outer cylinder 6 to be present. Instead, the pressure chamber could be of all steel construction, in which case the keys 26, the control rods 32 and the actuators 30 could be supported by a steel arrangement. Furthermore, a closure arrangement as disclosed herein could be used for purposes other than the sealing of high pressure chambers. For example the arrangement could be used as the closure of a steel pipe.

Claims

1. A high pressure chamber comprising a wall within which there is the hollow interior of the chamber, and a closure member for closing an opening of the chamber interior, the chamber further comprising locking elements which are movable between a release position, in which they are disposed outwards of the periphery of the closure member to allow the closure member to be removed from the opening, and a locking position, in which they engage edge regions of the closure member to prevent removal of the closure member from the opening, the locking elements being operable by control members which extend through the wall to actuating means disposed at or adjacent the exterior of the wall.

2. A high pressure as claimed in claim 1, wherein the locking elements occupy substantially the entire periphery of the closure member when in the locking position.

3. A high pressure chamber as claimed in claim 1 or 2, wherein the direction of movement of each locking element from the release position to the locking position is inclined to the plane of the opening such that each locking element moves towards a point on the centre line of the opening situated externally of the chamber.

4. A high pressure chamber as claimed in claim 1 or 2, wherein the direction of movement of each locking element from the release position to the locking position is parallel to the plane of the opening.

5. A high pressure chamber as claimed in any one of claims 1 to 4, wherein the locking elements when in the release position are accommodated within an annular groove provided in the wall of the chamber.

6. A high pressure chamber as claimed in any one of claims 1 to 5, wherein the locking elements comprise keys connected to the actuating means by rods, constituting the control members, which extend through the wall of the chamber.

7. A high pressure chamber as claimed in claim 1 or 4, wherein each locking element is constituted by an end portion of a beam, a further portion of which constitutes the associated control member.

8. A high pressure chamber substantially as hereinbefore described with reference to Figures 1 to 4, or Figures 5 and 6, or Figures 7 and 8, of the accompanying drawings.