GB2368599A

GB2368599A - Inflatable enclosures

Info

Publication number: GB2368599A
Application number: GB0122687A
Authority: GB
Inventors: David Kelsall
Original assignee: LINDSTRAND BALLOONS Ltd
Current assignee: LINDSTRAND BALLOONS Ltd
Priority date: 2000-09-21
Filing date: 2001-09-20
Publication date: 2002-05-08
Anticipated expiration: 2021-09-20
Also published as: GB0023187D0; GB0122687D0; GB2368599B

Abstract

An inflatable enclosure includes inflatable hoop like structures 1, 2 connected by inflatable membranes 6. One hoop 1 is secured to a base surface 3 and the other hoops 2 extend from a hub 4. Each hoop 1,2 comprises a hollow tubular member which is inflated by a fan unit or compressor housed in a housing unit 5. The membranes 6 are inflated by a second fan unit or compressor also housed in the housing unit 5. The pressure used to inflate the hoops 1, 2 is greater than that used to inflate the membranes 6. The hoops 2 swing about hub 4 to open fan-wise as the hoops 1, 2 and membranes 6 are inflated. The leading hoop 2 incorporates catch devices 7 which engage with clamps 8 embedded in the base 3 to hold the leading hoop 2 down forming an enclosure when fully inflated.

Description

Title :

Inflatable Enclosures.

This invention relates to inflatable enclosures and more particularly to an inflatable enclosure for use in the open air and by which large apparatus or machines may be covered to protect them from the elements and readily uncovered for operational use. One field of use of the enclosure of this invention is for protecting an astronomical telescope, particularly one located at a remote exposed site. This invention is not limited in respect of the apparatus to be protected.

One object of this invention is to provide an enclosure which may be opened-out or extended to cover an object using air pressure and, when required, air pressure is released to permit deflation, to uncover the object.

According to this invention there is provided an enclosure means comprising a plurality of support hoops of tubular section and inflatable by a first air pressure means to be self-supporting, each two adjacent hoops being connected by a membrane inflatable by a second air pressure means and forming a spaced connection between the hoops, the hoops being movable from a first position lying in a deflated stacked juxtaposed relationship to a second position following inflation of the hoops and membranes and in which the hoops and membranes open up to define an enclosure.

The hoops will preferably be of a flexible tubular fabric which will be airtight when inflated and of a preferably semicircular. The respective adjacent ends of each of the hoops may be located together at a common support

position and about which they may swing to thus open fan-wise in the manner of a hood. The membranes are positioned between adjacent hoops and are formed by two or more fabric layers which may be inflated thus forcing open the hoops.

The final opened state of the enclosure, in a preferred embodiment, thus defines a hemisphere. Other shapes are possible by appropriate shaping of the hoop supports.

To enable this invention to be better understood an embodiment, by way of example only, will be described in conjunction with the drawings. In the drawings: Fig 1 shows a plan view from above of an embodiment according to this invention, with the enclosure closed, Fig 2 shows a side view of the embodiment of Fig 1, Fig 3 shows a rear view of the embodiment of Fig 1, Fig 4 show a detail at"A"on Fig 2 and of a securing clamp, and Fig 5a to Fig 5h show the sequence of operation in opening of the enclosure.

Referring to Figs 1 to 3 of the drawings the enclosure includes seven hoop-like structures, one hoop 1 is secured to a base surface 3 and the other hoops 2 extend from a hub 4 about which they may swing. Each hoop comprises a hollow tubular member, here of circular cross-section, which may be inflated through a fan unit or compressor housed In unit 5 Connecting

adjacent hoops are membranes 6, which may be segmented double-wall structures, and which may be inflated by a second fan unit or compressor also housed in unit 5. The pressure used for inflating the hoops 1 and 2 is greater than that used for the inflation of membranes 6.

The leading hoop 2 includes a series of catch devices 7 which engage respective clamps 8 embedded in the base 3 and shown in Fig 4. These serve to hold down the leading hoop forming a robust enclosure when fully inflated and as shown in Figs 1 to 3.

For operation the structure includes two cables 9 which attach to the lip of the leading hoop 2 and extend over the enclosure, over pulleys 10 to a control unit 11.

In this structure the hoops 2 form high pressure inflated stiffening means whilst the membranes are a double skinned construction inflated at a lower pressure.

The opening sequence of operation of the enclosure is described and shown with reference to Fig 5 a to h: In Fig 5a the enclosure is shown fully closed as in Figs 1 to 3. In the first phase of opening the clamps 7,8 are released, for example using pneumatic control, and the low pressure fan in unit 5 turned off and bleed vents opened. A winch in unit 11 operates and draws in the cables 9 lifting the leading hoop 2 and deflating the interposed membrane 6. As the membranes deflate the enclosure opens as shown in Fig 5 c to f with the hoops progressively rotating about the hub 4 until the position shown in Fig 5 g is reached where all the

membranes 6 are deflated and the hoops lie stacked one upon the other. At this point the high pressure fan IS turned off and the pressure vented to permit the hoops 2 to collapse to the position shown in Fig 5 h. The cables 9 may be used to assist deflation.

The closing of the enclosure is carried out by a reverse sequence with the cables 9 being allowed to run out as the enclosure inflates. This is achieved by the hoops 2 first being inflated after which the membranes 6 are inflated to extend the structure.

The enclosure is comprised of a hemispherical, double skinned, low pressure inflatable fabric shell with additional high pressure inflatable fabric stiffeners. One of the problems that exists when constructing large fabric structures which are integrated with rigid structures is the interface between the two. This problem is eliminated with the proposed enclosure as it contains no rigid mechanical structures. This also eliminates the requirement for expensive hinge mechanisms, actuators, bearings etc. that are associated with large mechanical structures.

The absence of rigid structure within the enclosure also minimises the risk to personnel during operation and also greatly reduces the problems associated with the build up of ice in the joints between enclosure sections.

The high pressure stiffeners provide support when the low pressure structure is deflated during the opening and closing operations and provide additional rigidity when the enclosure is fully inflated. This ensures that the enclosure can withstand the maximum loading due to wind, snow or ice.

The high and low pressure structures that make up the enclosure are completely independent. In the event of a loss or pressure in one structure, the other would have sufficient rigidity to support the enclosure and to prevent the structure from collapsing. If required, both structures could have back up fans that would start up if either of the primary fans failed. If either structure was punctured, the fans would have sufficient capacity to compensate for a significantly large hole. Both structures would be constructed to be virtually airtight. This means that once inflated the fans would only operate intermittently to maintain the internal pressure thereby minimising power consumption. The pressure in each structure would be continuously monitored using transducers linked to a control system that operates the fans. A backup generator would be included to provide power in the event of failure of the local supply.

The fabric used in the construction of the enclosure would be selected to provide the structural strength required to withstand the loads that would be present throughout the life span of the enclosure. In addition, the fabric would be air tight and would have sufficient UV resistance to ensure a life span greater than five years. The low cost and ease of transportation and installation of the fabric structure would make its periodic replacement feasible. The fabric is to be made up of a plain weave polyester base cloth with an aliphatic polyurethane coating/laminate on both sides. The outside face would have an aluminised coating/laminate to provide thermal stability inside the enclosure.

Another feature of the proposed enclosure is that it is a single piece hemisphere that rotates through 180 degrees and seals at floor level. This

negates the need for complicated sealing mechanism with its inherent alignment problems that would be required for an enclosure made up of two halves. The proposed enclosure would provide an effective seal with the floor due to the internal pressure and the flexible nature of its construction. Clamps would also be employed to lock the enclosure in the closed position to prevent it lifting in high winds. It is proposed that these are pneumatic clamps that require air pressure to open and rely on spring pressure to close. In the event of failure of the compressed air system the clamps would remain closed ensuring that the telescope is protected.

The design of the enclosure is such that hazardous substances such as hydraulic oil are not present. The compact nature of the enclosure also ensures that its impact on the surrounding environment is minimised.

Claims

CLAIMS : 1. An enclosure comprising a plurality of support hoops of tubular section and inflatable by a first air pressure means so as to be self-supporting, each two adjacent hoops being connected by a membrane inflatable by a second air pressure means and forming a spaced connection between the hoops, the hoops being movable from a first position lying in a deflated stacked juxtaposed relationship to a second position following inflation of the hoops and membranes and in which the hoops and membranes open up to define an enclosure.
2. An enclosure according to claim 1, wherein the hoops are of a flexible air-tight fabric material and of tubular form when inflated.
3. An enclosure according to claim 1 or 2, wherein the respective adjacent ends of each of the hoops are located together at a common support position and about which they may swing to thus open fan-wise in the manner of a hood.
4. An enclosure according to claim 1 or 2 or 3, wherein the membranes are positioned between adjacent hoops and are formed by two or more fabric layers which on inflation force apart the hoops.
5. An enclosure according to any preceding claim, wherein in the final opened state the enclosure defines a hemisphere.
6. An enclosure according to any preceding claim, wherein a plurality of hoop structures are provided, one hoop being secured to a base surface and the other hoops extending from a hub about which they may swing, each hoop comprising a hollow circular cross-section tubular member, inflated through a

fan unit or compressor, adjacent hoops being connected by membranes of a segmented double-wall construction and which may be inflated by a second fan unit or compressor, the pressure used for inflating the hoops being greater than that used for the inflation of membranes
7. An enclosure according to any preceding claim, wherein a leading hoop includes a series of catch devices which engage respective clamps embedded In the base to hold down the leading hoop.
8. An enclosure according to any preceding claim, wherein the structure includes two cables which attach to the front lip of the leading hoop and extend over the enclosure to a control unit to draw in the cables to open the structure.
9. An enclosure according to any preceding claim, wherein the hoops form high pressure inflated stiffening means, the membranes being a double skinned construction inflated at a lower pressure.
10. An inflatable enclosure primarily for protecting large items of apparatus from the environment substantially as described herein and exemplified with reference to the drawings.