GB2218179A

GB2218179A - Pipe or vessel closure

Info

Publication number: GB2218179A
Application number: GB8908739A
Authority: GB
Inventors: James Alistair Pearson
Original assignee: Plenty Ltd
Current assignee: Plenty Ltd
Priority date: 1988-04-22
Filing date: 1989-04-18
Publication date: 1989-11-08
Anticipated expiration: 2009-04-18
Also published as: GB8908739D0; GB2218179B; GB8809516D0

Abstract

A closure 1 for an opening 3 in a pipe or vessel 4 adapted to co-operate with a circular groove 11 or bead around the opening, the closure 1 comprising a circular cover, an angularly displaceable member 9 pivoted at the centre of the cover and at least two arcuate locking members 2 positioned around the periphery of the cover, wherein each locking member 2 is driven outwardly by the angularly displaceable member 9 through gearing comprising a wheel 7 and gears 8 which operate cams 8A to act on the locking members 2. <IMAGE>

Description

IMPROVED CLOSURE FOR PIPE OR VESSEL This invention relates to a closure for pipes or vessels. British Specification No. 1603814 discloses closure for an opening in a pressure vessel or pipe adapted to co-operate with a circular groove or bead around the opening, the closure comprising a circular cover, an angularly displaceable member pivoted at the centre of the cover and at least two arcuate locking members positioned around the periphery of the cover, each locking member being linked at one end to the angularly displaceable member and so pivoted or constrained that in operation when the closure is fitted to the container and the angularly displaceable member turned in the required direction relative to the cover, locking members move into engagement with the groove or the bead thereby locking the closure in position.Such a closure will hereafter be referred to as 'a closure of the type described'.

In a closure of the type described in accordance with the invention the locking member(s) are driven outwardly by the angularly displaceable member through gearing comprising a sun wheel and planet gears operating cams to act on the locking members.

A releasable bridge member for interconnection between the closure and pipe or vessel is preferably arranged so that initially on disengagement of the or each locking member, the closure can only be partially opened after which the bridge member may be released to allow the closure to be completely opened when, and only when, the pressure within the pipe or vessel has fallen to a safe level.

A vent valve as disclosed in Patent Specification Nos. 1181757, 1603814 and 1367860 is preferably provided and arranged so that opening the valve enables the angularly movable member to be moved in order to release the locking members only when the pressure in the pipe or vessel has been vented.

In use there are three positions. The first position in which the closure is closed and the bridge member cannot be released from its set position to allow opening of the closure. The second position in which the closure is partially opened, the bridge member being arranged so that it still cannot be released from its set position to allow full opening of the closure and the third position different from the first and second positions in which the bridge member may be released to allow the closure to be fully opened.

The bridge member therefore, prevents the closure being fully opened, for example by pressure within the pipe or vessel, protecting operating personnel from injury. If there is pressure tending to open the closure against this bridge member then the closure must be pushed physically back into the vessel against the pressure before the latch can be released. The safety vent would give a warning that this was not safe in addition to the physical force needed to push to door against the pressure within the vessel.

The invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a sectional side elevation of a closure in the closed position.

Figures 2-A, 2-B and 2-C are front elevations showing the operation of the handle co-operating with central gear ring to actuate the planet gears which form part of the eccentric cams to operate the arcuate locking members.

Figures 3-A, 3-B and 3-C illustrate arcuate locking members with alternative operation of the cam to push the locking member into the locking groove.

Figures 4-A, 4-B and 4-C illustrate the vent and safety bar which operate with the angularly displaceable member to prevent opening of the closure until the safety vent is opened.

Figure 5 illustrates an alternative bridge member which prevents full opening of the closure until the pressure within the pipe or vessel is reduced.

In Figure 1, the Closure 1 has locking members 2 for locking the Closure 1 in the opening 3 of the pipe or vessel 4. Locking members 2 are operable to lock the closure in position with angular movement of a handle 5 to which locking members 2 are connected.

For a more particular description of the Closure 1 reference is directed to our prior British Patents Nos. 1367860 and 1603814. The Closure 1 and the pipe or vessel 4 also include various seals of known type generally indicated 6.

The arcuate locking members of the present invention are moved through gearing comprising a central or sun wheel gear 7 engaging a planet gear 8 for each arcuate locking member.

Each planet gear has an eccentric lobe or cam 8A which moves the corresponding arcuate locking member 2 into or out of engagement. The locking member may move into a rectangular section, an around or hemispherical section groove as directed by design stresses.

Figure 2 view under the weatherproof cover 20 illustrates the operation of the central gear wheel 7 co-operating with, typically, three planet gears 8 each moving an arcuate locking member 2. The central sun gear 7 may be rotated either by its own separate handle 9 (Figure 2-A) or by an additional planet gear 10 (Figure 2-B) co-operating with a handle 5 or a handle on a planet gear (Figure 2-C) such that angular movement of the handle displaces the central 7 gear in an appropriate angular displacement. The handle can be left hand, right hand or any assembly around the closure as desired.

Figure 3 illustrates alternate types of angular locking members 2 having a cam operation 8A at one end and a slot 17 at the other (Figure 3-A) or alternatively a fixed pivot point 18 and a cam 8A co-operating with a slot at the other (Figure 3B) or a cam 8A with guides 19 to locate the member (Figure 3-C). Angular movement of the cam moves the angular locking member into or out of engagement on a curved or radial path. The angular locking member co-operates with a groove 11 in the closure which may also be semi-circular or rounded for reduction of local stresses.

Figure 4-A illustrates the co-operation of the opening handle 5 with a central safety vent 12 and Figure 4-B illustrates the co-operation of the off centre safety vent 13 with a handle 9 attached directly to the central sun gear. Figure 4-C illustrates a handle co-operating directly onto a planet gear. In both cases it is necessary for the safety vent to be unscrewed to a position in which the larger diameter is clear of a locking plate before the operating handle can be angularly moved.

Figure 5 indicates a bridge member 14 of a different form than that in Patent No. 1603814 but basically having the same safety features. A spring loaded plate 15 which can be attached to either the cover or the pipe or vessel engages with a projection 16 on the other part of the pipe or closure. When the closure has been released to the open position pressure will force the latch to co-operate with the bridge member such that the closure is prevented from opening further until the pressure within the vessel is significantly reduced to allow the door to be moved against the pressure to disengage the opposed forward edge of the latch.

The closure may be released from the position shown in Figure 5 by allowing pivotable movement of the bridge member 14, to clear the bridge member 14 from engagement with the projection 16. This door restraining mechanism is an alternative arrangement of that disclosed in Patent No. 1603814.

Claims

CLAIMS:

1. A closure for an opening in a pressure vessel or pipe adapted to co-operate with a circular groove or bead around the opening, the closure comprising a circular cover, an angularly displaceable member pivoted at the centre of the cover and at least two arcuate locking members positioned around the periphery of the cover, each locking member being driven outwardly by the angularly displaceable member through gearing and being so pivoted or constrained that in operation when the closure is fitted to the container and the angularly displaceable member turned in the required direction relative to the cover, locking members move into engagement with the groove or the bead thereby locking the closure in position, the gearing comprising a sun wheel and planet gears which operate cams to act on the locking members.

2. A closure as claimed in Claim 1 comprising a releasable bridge, for interconnection between the closure and the pipe or vessel, so arranged that, on initial disengagement of the or each locking member, the closure can only be partially opened into a position in which the bridge member may be released to allow the closure to be completely opened when and only when the pressure in the vessel has fallen to a safe level.

3. A closure as claimed in Claim 1 or 2 wherein a vent valve is provided, so that opening the valve enables the angularly displaceable member to be moved only when the pressure in the vessel is vented.

4. A closure substantially as herein described with reference to and shown in the accompanying drawings.