US3783766A

US3783766A - Enclosures

Info

Publication number: US3783766A
Application number: US00223234A
Authority: US
Inventors: R Boucher
Original assignee: EPS Ltd
Current assignee: EPS Ltd
Priority date: 1971-02-10
Filing date: 1972-02-03
Publication date: 1974-01-08
Anticipated expiration: 1991-01-08
Also published as: GB1362263A; FR2126815A5; DE2206819C3; DE2206819B2; DE2206819A1

Abstract

The invention concerns enclosures having especial application in relation to storing equipment liable to atmospheric deterioration comprising a rigid base having a strip peripherally secured thereto with coupling means sealingly to connect the strip to a bag-like cover to provide a generally weather proof enclosure.

Description

,lan. 8, 1974 United States Patent 1191 Boucher ENCLOSURES 2,731,055 1/1956 Smith 52/2 3,009,540 11/1961 165/7 x [75] Invent Bouche" Mlnsted, 3,088,619 5/1963 Boucher........................ 150/52 R x near S1ttmgbourne, England 3,103,083 9/1963 2,752,928 7/1956 Seeger....... Barker.... [7.3] Asslgnee' E; g ':fg 3,500,593 3 1970 Kwake.... gan 3,241,269 3/1966 Reffell........,...... 22 Filed; 3 1972 3,557,515 [/1971 MacCracken.....

[2l] Appl. No.1 223,234

Primary ExaminerMeyer Perlin Assistant Examiner-Ronald C. Capossela [30] Forelgn Apphcatwn Pnomy Data Attorney- Parmelee, Miller, Welsh & Kratz Feb. 10, 1971 ABSTRACT The invention concerns enclosures having especial application in relation to storing equipment liable to atmospheric deterioration comprising a rigid base hav- 2 N2 2 f 3 M6 13 m2 "2 Mb c .r "a e S m d Ld hr. .1] 00 55 98/33 R; 150/52 R; ing a strip peripherally secured thereto with coupling [56] 1 References Cited means sealingly to connect the strip to a bag-like cover to provide a generally weather proof enclosure. UNITED STATES PATENTS 3,626,836 12/1971 Schneidler '6 Claims, 9 Drawing Figures PATENTEDJAN 8 1974 SHEET 2 OF 6 PATENTED JAN 8 I974 SHEET 5 OF 6 ENCLOSURES This invention relates to enclosures having especial application as protective containers for heavy equipment such as land and water vehicles, aircraft or the like, stores and provisions and any equipment and spares therefor which are prone to deterioration. The invention relates also to systems including an array of such containers or enclosures arranged and adapted for convenient supervision.

In certain applications, especially for example, in the military field it is necessary to store large quantities of valuable equipment, e.g., large numbers of vehicles spares for vehicles and other equipment over longperiods of time, without substantial deterioration occurring even in the absence of regular servicing of the equipment and yet in such a fashion that such equipment can be brought into service rapidly at short notice.

If no protection from corrosion and deterioration through atmospheric conditions is given to vehicles and the like it is necessary to service them very regularly to maintain them in good condition. Obviously, where large numbers of vehicles are concerned this involves considerable effort on behalf of numerous very skilled personnel and thus great expense.

Whilst some degree of protection from damp and consequent deterioration through corrosion etc., can be given by storing the vehicles and other equipment in buildings or huts of a prefabricated, but of generally permanent, nature, economic considerations as well as considerations of space dictate that a single such building should house a large number of vehicles and equipment.

If air conditioning is to be employed to maintain a low level of relative humidity in the buildings more economic use can be made of the air conditioning plant if as few buildings as is possible are used to house a maximum number of vehicles and large quantities of equipment. Unfortunately where a large number of vehicles and/or equipment is stored in a single building it may not be possible in an emergency to bring all of the vehicles and equipment into use as quickly as is desired.

Furthermore a building or but within which a large number of vehicles and/or equipment is accommodated (in close proximity) makes a conveniently large and valuable target for an enemy in the event of enemy action and still further may well present a serious fire hazard in normal conditions.

According to one aspect of the present invention there is provided an enclosure comprising a permanent rigid base formed in a manner as to discourage water vapour transmission; a strip of flexible sheet material of low water vapour transmissibility extending around the periphery of said base; first means sealingly attaching said strip to said base; a cover of generally open baglike form formed of flexible sheet material of low water transmissibility having a mouth; connecting means about said mouth; and co-operating connecting means on said strip sealingly to connect said .strip to said cover.

According to another aspect of the present invention there is provided an enclosure for an article comprising: a permanently formed ground secured rigid base formed in a manner as to discourage water vapour transmission; a peripheral recess extending around said base; a strip of flexible sheet plastics material of low water vapour transmissibility having one longitudinal edge portion sealingly secured to the base; one half of a sliding clasp fastener extending along of other longitudinal edge portion of the strip; a cover of open-bag like form formed of flexible sheet plastics material of low water vapour transmissibility having a mouth, a second half of said sliding clasp fastener extending about the edge portion of the cover constituting said mouth and sealingly, but releasably, connected to the fastener half on said strip; said base recess being dimensioned to house said strip when such strip is not connected to said cover to provide protection for the strip when the article isplaced on, or removed from, the base; the arrangement being such that when the sliding clasp fastener halves are interconnected a substantially hermetically sealed enclosure is provided and an enviroment may be maintained within the enclosure having a lower relative humidity than the ambient air outside the enclosure and yet permits for ready removal of the article from the enclosure.

According to yet another aspect of the present invention there is provided an installation comprising a plurality of enclosures as referred to hereinbefore.

According to a still further aspect of the present invention there is provided an air-supported or inflated enclosure comprising: a rigid base; a peripheral recess extending around the base; a strip of flexible substantially water and air impermeable plastics material having one longitudinal edge portion secured to-the base; a cover of open bag-like form formed of a substantially water and air impermeable flexible plastics sheet material having a mouth; complementary halves of a sliding clasp fastener being secured respectively to a second longitudinal edge of the strip and about the edge portion of the mouth of the cover to permit the strip and the cover to be sealingly but releasably interconnected to form an enclosure; and an inlet and an outlet in said enclosure, each of generally frusto-conical form and being formed of a flexible material.

It is desirable to provide a plurality of particular base and cover sizes so that broadly a modular system is created and in this way permitting mass production of the components and thus minimising the production of special one-off covers. I

In order that the invention may be more readily understood and further features of the same more readily appreciated, various embodiments of enclosure in accordance with the invention will now be described (as will certain ancillary equipment used with such enclosures) by way of example with reference to the accompanying drawings in which:

FIG. I is a diagrammatic vertical sectional view of a typical embodiment of enclosure; FIG. 1A is an enlarged fragmentary sectional view showing the form of a sliding clasp fastener used to couple two portions of the enclosure sealingly but releasably together;

FIG. 2 is a fragmentary enlarged sectional view show ing a peripheral edge portion of a base of the enclosure with a strip provided for connection to a cover shown coiled in a stowed condition;

FIG. 3 is a view very similar to FIG. 2 showing an alternative arrangement of base with strip;

FIG. 4 is a generally diagrammatic and schematic view of an installation showing a series of enclosures in different conditions of assembly and showing diagrammatically various items of ancillary equipment and also a humidity monitoring arrangement;

FIG. is a part-elevation, part-vertical sectional view through a generation desiccator used as ancillary equipment in enclosures according to this invention;

FIG. 6 is an exploded, part-diagrammatic, perspective view of a frame-arrested recirculatory regeneratable dehumidifier also used as ancillary equipment with the enclosures in accordance with this invention;

FIG. 7 is a part diagrammatic perspective view, partially cut away, of a housing suitable for a helicopter the helicopter being omitted for the sake of clarity; and

FIG. 8 is a part diagrammatic side elevational view of a further embodiment of enclosure suitable for use as a workshop and comprising an air supported/inflated enclosure, such view showing ancillary equipment used with such enclosure.

In one embodiment of enclosure for storing vehicles the enclosure comprises a base comprising a seal formed by a sheet of plastics material 1 which has a low water vapour transmissibility being laid on the ground 2, and superimposed by a layer of concrete 3 which forms a rigid, substantially permanent, platform or base. The layer of concrete is edged with channel section girders 4 (of a metal or of a plastics material), the

sides

5, 6 of the channel extending in the same plane as the upper and lower surfaces of the platform and the channel 7 defined thereby being open outwardly. Sealingly secured within the channel is one longitudinal edge portion of a strip 8 of sheet (for example plastics) material which extends around the base 3. The free longitudinal edge of said strip is provided with one of the complementary parts 9 of a sliding clasp fastener such as described in US. Pat. No. 3,088,619 and which is shown in FIG. 1A.

The remainder of the enclosure is defined by a cover 10 in the form of a bag having an open mouth, the peripheral edge of the bag defining such mouth being provided with the other complementary part 11 of the aforementioned sliding clasp fastener.

When the enclosure is not in use and is bereft of its cover 10 the base has said flexible strip 8 rolled back and accommodated within the channel 7 all around the base, so that the strip 8 is protected when a vehicle or equipment is moved onto, or from the base 3. FIG. 2 shows this arrangement.

In use, after for example a vehicle such as a tank or lorry has been driven onto the base 8 (the vehicle lying entirely within the boundary of the base 8) the vehicle is covered with said cover 10, said strip 8 is unrolled from said channel 7 and the complementary parts or

halves

9, 1 1 of the sliding clasp fastener are secured together using a sliding clasp in known fashion.

If desired in an alternative arrangement the channel sectioned girders may have sides which lie within and at right angles to the plane of the base. This embodiment is shown in FIG. 3 and the channel section girders are designated 20, the sides 21, 22 and the channel defined therebetween 23; the seal being designated 24.

A complete system or installation may comprise a plurality of such bases 3 laid in appropriate arrangements such as, for example, rows, part of an installation being shown in FIG. 4 of the accompanying drawings. When the enclosures have been filled with vehicles and equipment and have been sealed the air contained within the enclosures is dehumidified as will be described hereinafter.

However in an installation many, if not all, the enclosures would each contain a relative humidity senser diagrammatically shown and designated 25 electrically connected by wires 26 which pass sealingly through the covers and these wires 26 are connected to a terminal 27, and by respective further conductors 28 (only diagrammatically shown) to a monitoring station 29 common to a plurality of containers at which point one or more indicators reading the information provided by the sensers 25 are provided.

It will be appreciated that any suitable relative humidity senser may be utilised. One form of senser may comprise a sodium chloride impregnated length of ribbon which changes its electrical resistance in response to changes in humidity.

After closing an enclosure the relative humidity therein is initially reduced to an acceptable safe level by the use of a dehumidifier which may take any suitable form, for example, a replaceable static (but regeneratable) desiccator 30 (shown in FIG. 5 in detail) located in the enclosure or by means of a transportable or permanent recirculating dehumidifier 31 (shown in FIG. 6 in detail). Such a dehumidifier may be electrically powered and may be connected to a source of electricity via an electrical socket located in, or adjacent said enclosure.

After a certain storage period at an acceptable relative humidity level, increase in such relative humidity above an accepted level (the increase being due to some water vapour transference through the enclosure) will be indicated at the common monitoring station 29 and when the humidity within any of the enclosures rises above the predetermined acceptable level, the appropriate indicator registers this fact (either on a relative humidity-calibrated dial or by means of a visual or an aural alarm or otherwise) and the person responsible for such stored equipment can take appropriate action, which may either be to replace the desiccator 30 within the appropriate enclosure or which may alternately be to activate the dehumidifier 31.

The dehumidifiers and desiccators may taken a variety of forms but suitable types will be briefly described hereinafter.

Still further, while each enclosure may be provided with its own permanent dehumidifying device located therewithin, the enclosure may alternatively be provided with an inlet 32 and outlet 33 (both sealable when not required) connectable by hoses 34, 35 to a portable dehumidifier 36.

One embodiment of regeneratable desiccator 30 will now be described briefly. In this embodiment the desiccator comprises a cylindrical drum 40 constituting a body, closable when being stored and unused sealingly by a lid 41, the drum 40 being divided into two compartments by a perforated divider 42, a first lower compartment 43 housing heating means in the form of a fan heater 44 whereas the second upper compartment 45 houses a plurality of cages 46. Each cage has perforated top and

bottom walls

47, 48 retained in spaced parallelism by a flange on a cylindrical side wall 49, the side wall 49 of each case having a rib 50 to space its cage from the internal surface of the drum 40. Pelletised silica gel forms the desiccant and is provided in each cage, the pellets being designated 51.

To assist transportation of the drum 40, for example when removing from, or introducing into, an enclosure such desiccator, a handle 52 is provided.

The system adopted when using a desiccator of this type is first to ensure that the desiccant is active by energising the heater 44 with the lid 41 removed to drive moisture from the desiccant and then to seal the desiccator completely. The desiccant is then transported and placed in an enclosure to be dehumidified and the lid 4lll removed and then the enclosure is sealed. When the desiccant becomes saturated the desiccator is removed from the enclosure and replaced by yet another such desiccator, the desiccator which has been removed'then having its desiccant regenerated.

One embodiment of dehumidifier which could be used is described and claimed in our US. Pat. No. 3,594,990. However because vapours in the enclosures may well be inflamable or explosive the dehumidifier preferably includes flame arrest means.

A flame arrest dehumidifier will now be briefly de scribed by way of explanation.

The dehumidifier comprises a body 611 having an inlet chamber 62 and an outlet chamber 63 separated by a partition 64. The inlet chamber 62 houses an electric fan 5 (not shown), and the outlet chamber 63 houses a combined heating and desiccating core 63a comprising a wire heating element wrapped in a desic cant carrying material.

A pair of opposed inlet ports 65 are connected by lengths of conduit 66, 67 respectively to a control valve unit 68, which serves to connect one or other of such inlet ports to the inlet chamber 63. Similarly, a pair of outlet ports 69, are connected by lengths of conduit 70, 71, respectively to a second control valve unit 72 which serves to connect one or other of the outlet ports to the outlet chamber 63.

One boundary of the outlet chamber 63 is constituted by an end wall 73 that is provided with a large aperture 74 therein. Equally spaced around the aperture 74 and extending outwardly of the end wall 73 are four studs that are threaded at their ends remote from the end wall 73. The'studs carry a circular valve plate 75 (constituting a valve member) that consists of a circular member having a radius greater than that of the aperture 74, the circular member being provided with four apertured semi-circular lugs for slidable association with the studs. A rectangular retaining plate 76 serves to limit the distance along which the valve plate 75 may.

be moved on the studs. There is provided on each stud a helical compression spring 77 positioned between, and engaging with, the valve plate 75 and the retaining plate 76, and acting to bias the valve plate 75 towards a closed position against the end wall 73 of the outlet chamber 63. A silicone rubber seal is provided between the valve plate and the end wall 73 so that the plate will satisfactorily seal the aperture 76. The retaining plate 76 is provided with a valve plate arresting spring 73.

The end plate 73 is also provided with a rectangular aperture 79 which communicates with a volume within the interior of the body 611 of the dehumidifier and which lies above the outlet chamber 63. Both the aperture 74 and the aperture 79 are provided with baffles made of a flame resistant or flame arresting material such as chromised nickel RETIMET (Trade Mark) referenced 80 and 81 respectively. Both of the baffles 80, 31 are connected to the end wall 73 in such a manner that all gasses and/or vapours passing through the

apertures

74, 79 must pass through the baffles. Appropriate retaining plates are provided to retain the aforementioned components in their operative positions. Although only one end of the body 61 has been described and illustrated it is to be understood that the opposite end of the body is as has been described hereinbefore.

The inlet port 65 is constituted by a short length of pipe that leads to a cuboid housing 82 mounted on the side of the body 61 of the dehumidifier. Contained within the housing 82 there is a baffle 83 of flame resistant material such as, for example, said chromised nickel RETIMET (Trade Mark) which entirely fills the housing. A length of conduit serves to connect the side of the housing remote from the port 65 to the control valve unit 68. Mounted on the conduit 9 there is a safety switch 84 which is sensitive to temperature or pressure and which will operate when the temperature or the pressure of gas and/or vapour within the conduit exceeds a certain predetermined value. Such a switch might, for example, include a bimetallic strip of a thermistor in which cases the switch will be sensitive to heat. Alternatively the switch may be any suitable switch that is sensitive to pressure. The switch is connected in a circuit which controls said electric fan in the inlet chamber 62. g

The structure of each of the inlet and outlet ports of the dehumidifier are similar to that of the inlet port 65 and consequently they will not be individually described in this specification.

Said electric fan may be of any suitable form and typically an axial flow fan may be utilised. The electrical fan is housed within a special housing which in turn is located within the inlet chamber 62. This special housing has an inlet aperture which is provided with a bafi'le of flame resistant material and which is retained in position by the retaining plate. Again the baffle may be made of any suitable flame resistant material such as chromised nickel RETIMET (Trade Mark).

Mounted within the body 61 is a control box 35 which contains the electrical equipment necessary to control the electric fan and the

control valve units

66, 69.

It will be apparent from the foregoing description that there are four safety switches 66 contained within the body ll, one for each inlet and outlet. The switches 34 are all connected in series between one electric power supply terminal and the electric fan so that if any of these switches is in the open circuit" condition the electric fan will be rendered inoperative.

in forming the dehumidifier thus far described the body and all the associated parts are very rigidly constructed, parts being welded together wherever practicable, in order to minimise the damage that may be caused to the equipment should an explosion occur therein. The dehumidifier is, in this particular embodiment a portable unit.

When it is desired to dehumidify the contents of an enclosure it is merely necessary to couple an inlet port (for example, the port 65) and an outlet port (for example the port 69) of the dehumidifier to the enclosure inlet and outlet by for example the flexible pipes 34, 35.

Assuming that the pipes are so coupled to the container and assuming that the

valve control units

68, 72 are in a suitable condition, energisation of the electric 'fan will result in the air and/or vapour within the container being drawn into the inlet port 65 and forced through the housing 62 and the baffle 83 contained therein and into the inlet chamber 62. The gas and/0r vapour will then pass to the fan and the fan will serve to propel the gas and/or vapour through an aperture in the partition 64 into the outlet chamber 63, where it will pass through said core. As the gas and/or vapour passes through the core it will come into intimate contact with the desiccant which is carried by the core, and water vapour contained within the gas and/or vapour will be absorbed by the desiccant. After passing over the desiccant the gas and/or vapour will then pass through the control valve unit 72 and thence to the outlet port 69. As the output port 69 is connected to the enclosure by the pipe 35, the gas and/or vapour extracted from the enclosure through the pipe 34 connected to the inlet port 65 of the dehumidifier is eventually returned to the container. This cycle of operation could be continued either until the humidity within the enclosure has dropped to desired level or until the desiccant ceases to be effective.

Once the desiccant has become ineffective (or at least only partially effective) the desiccant is regenerated by circulating air through the unconnected inlet and outlet ports with the core being heated so that water vapour is driven from the desiccant and is carried away and discharged through the unconnected outlet.

When the moisture has been driven from the desiccant the heating current is ceased and the valve contained within the control valve units are returned to their original condition, so that a dehumidifying cycle can be continued as and when desired.

When utilising the dehumidifier of the invention to dehumidify a container having an atmosphere of a gas and/or vapour mixture that contains explosive constituents there is a remote possibility that an explosion may occur within the dehumidifying unit with the result that there may be a subsequent fire within the body of the dehumidifier which might pass into the enclosure being dehumidified. In the event of an explosion within the inlet chamber 62 or the outlet chamber 63 the pressure within the chamber will rapidly rise and consequently .the pressure being exerted upon the valve plate 75 will also rise to such an extent that the valve plate 75 will be urged away from the end wall 73. Gas under pressure will then escape through the aperture 74, thereby relieving the excess pressure present within the cavity. The gas and/or vapour that escapes through the aperture 74 must pass through the baffle 80 of flame resistant material, and consequently should there be a fire present within the body of the dehumidifier the flames willnot pass through the baffle 80. However, should the fan still be propelling gas and/or vapour mixture into the chamber it is conceivable for any fire present within the chamber to continue thereby warming the baffle 80. Eventually the baffle 80 could reach such a temperature that it no longer has flame arresting properties, and consequently flames could pass through the bafile. However, the dehumidifier is provided with said safety switches (such as that designated 84) situated in the conduits leading to each of the inlet ports and each of the outlet ports which serve to render the electric fan inoperative as soon as the temperature and/or pressure within the conduits rises above a certain predetermined level. Consequently, if there were an explosion or a fire within the body of the dehumidifier, one or more of the safety switches 84 will be triggered and the fan will be made inoperative.

Each of the inlet ports and each of the outlet ports of the dehumidifier as stated hereinbefore is provided with a housing containing a baffle of flame resistant material so that should an explosion or a fire occur within the dehumidifier the flames will not be transmitted to the gas and/or vapour contained within the container which is being dehumidified.

Where the disadvantages of the use of huts and like permanent housing are not so prevalent the bases of the various enclosures may be formed with the floor of the building and each individual base is defined by a boundary formed by an upwardly open channel in the floor surface, the base and channel conveniently lined with moisture sealing material and with one longitudinal edge of said strip 8 sealingly secured to the channel.

Where tracked vehicles such as tanks are to be located in the base a pair of rigid elongate supports at the spacing of the tracks of the vehicles, may be laid over the base.

Another embodiment, which would be used for helicopters differs from that used for vehicles of a general type as described hereinbefore. In this embodiment the enclosure is profiled suitably as shown in FIG. 7 of the accompanying drawings and is provided with means to encourage circulation of the enviroment within the enclosure. This circulation is desirable as it has been noted that in certain shaped enclosures (such as this type) particular portions are prone to become excessively humid as compared with the general overall level of humidity in-the enclosure.

For the sake of clarity in FIG. 7, showing a helicopter enclosure, the helicopter has been omitted.

In this enclosure, which is designated 90, a fan blower 91 is diagrammatically shown having an inlet 92 and outlet 93 each provided with flame arrest material (as described in relation to the dehumidifier). The blower contains a tangential flow fan 91a and a heating element 91b of any desired form.

Connected to the outlet 93 of the blower 91 is a length of tubing 94 formed from a strip of a plastics material folded along its length and welded to itself to provide the tube 93 with an integral flange 95 which is secured, for example by welding, to the interior surface of the enclosure 90. The tube may be perforated at intervals therealong. The blower 91 is connected to a source of electricity by means of an electrical lead 96. This system for providing circulation of the enviroment within the enclosure is only necessary, or desirable, in enclosures of particular shapes.

The preferred material for the covers and the boundary strips in the embodiments described hereinbefore is plasticised polyvinylchloride sheeting, of various grades. preferably reinforced, for example, with terylene cloth. Antistatic additives may also be included. Polyethylene film may also be applied to the sheeting in certain applications for extra resistance to certain oils.

In order to protect this sheeting from wind stresses (which might result in tearing or stretching) it is preferred, after an enclosure has been sealed, to cover the cover with a relatively heavy net designated 97, which is thereafter secured at its edges in any desired manner around the boundary of the base.

It will be evident that the enclosure and system/installation provided by the present invention provide a means by which considerable costs may be saved in storing equipment by rendering unnecessary the construction of permanent or semi-permanent buildings for storage, and by reducing considerably the amount of preventitive maintenance which would otherwise have to be carried out. In addition it will be seen that the stored equipment can be brought into service extremely quickly and without undue effort.

The aforementioned enclosures described by way of example are all particularly suitable for housing one or more articles but as has been explained hereinbefore the invention also has application in relation to air supported or inflated enclosures which, whilst they could house articles, would nevertheless normally be used as workshops and maintenance rooms.

Thus in a further embodiment an enclosure suitable for a workshop comprises a rigid base 101, a peripheral recess extending around the base in the form of a metal channel 102 to which is connected one longitudinal edge portion of a flexible strip of material 103 formed of a substantially water and air impermeable plastics material, the opposite longitudinal edge portion of the strip 103 carrying one half of a sliding clasp fastener which is adapted to be sealingly connected to a complementary half of the fastener which is secured around the mouth of a cover 104 of generally open bag-like form. This cover 104 is provided with a slit which con stitutes a doorway and this slit is sealingly closable by a similar sliding clasp fastener 105.

Oppositeend portions of the cover 104 have respectively an inlet and an outlet.

The inlet comprises a circular aperture around which is located a collar 108to which is secured a frustoconical sleeve or tube 106 also formed of a flexible plastics material, such cone being arranged to protrude either to the interior of the cover or to protrude to the exterior thereto. This conical inlet is provided for connection to a'blower located either outside or within the enclosure and such blower is designated 107, the

blower being shown in dotted lines in the interior of the enclosure and in full lines at the exterior of the enclosure merely by way of illustration that two alternative locations are available. Peripheral sealing means are provided around the collar 108 these sealing means being adapted to co-operate with complementary sealing means on a closure cap 109.

The outlet which is also a circular aperture in the wall of the cover 104 is provided with a'collar identical to the collar 108, the outlet collar being designated 110 to which is connected a frusto-conical hollow sleeve 111 identical to the sleeve 106.

Again a closure cap equivalent to the cap 109 is provided for closing the outlet, this cap being designated 112 and having sealing means for co-operation with the collar 110.

As both inlet and outlets and their associated sleeves 106 and 111 are identical it will be understood that their roles may, when required, be reversed.

Placed over the cover 104 is a netting which is provided with an appropriate closable opening to permit access to be gained to the sealable access slit in the side of the cover 104, the opening in the net being designated 113 and the net itself being designated 114.

The nature of the material, which is conveniently plasticised polyvinylchloride (reinforced as and when the exterior air pressure the conical sleeve 11] will droop (as shown in dotted lines) effectively substantially closing the outletso that unnecessary egress of any air being introduced into the cover by the blower 107 positioned at the inlet is avoided. The arrangement however is such that as the air pressure increases within the cover the frusto-conical sleeve 111 becomes erect and permits air to escape at a sufficiently high rate to provide a desirable exchange of air within the cover but not atva rate which would permit the cover to collapse at least when the blower is operative.

The slit normally sealed by the clasp fastener is arranged so that when opened to permit entry of a person into the cover, immediate deflation of the cover does not occur, any sudden drop in differential pressure between the exterior and the interior of the enclosure resulting in the outlet sleeve 111 drooping and at least partly closing.

The blower may of course include filters or be associated with filters, dehumidifiers, air conditioners and items such as heaters 107a so that the precise air conditions within the cover may be maintained. As and when desired the inlet and the outlet may be closed by the

caps

109, 112.

I claim:

1. An enclosure for an article comprising:

a permanently formed ground secured rigid base formed in a manner as to discourage water vapour transmission;

a peripheral recess extending around a portion of said base; I

a strip of flexible sheet plastics material of low water vapour transmissibility having one longitudinal edge portion sealing secured to the base;

one half of a sliding clasp fastener extending along the other longitudinal edge portion of the strip;

a cover of open bag-like form formed of flexible sheet plastics material of low water vapour transmissibility having a mouth;

a second half of said sliding clasp fastener extending about the edge portion. of the cover constituting said mouth and sealingly, but releasably, connected to the fastener half on said strip;

said base recess being dimensioned to house the portion of said strip adjacent said peripheral recess when such strip is disconnected from said cover to provide protection for that portion of the strip when the article is placed on, or removed from, the base;

the arrangement being such that when the sliding clasp fastener halves are interconnected a substantially hermetically sealed enclosure is provided and an environment may be maintained within the enclosure having a lower relative humidity than the ambient air outside the enclosure and yet permits for ready removal of the article from the enclosure.

2. An enclosure according to claim 1, wherein humidity sensing means are provided within the enclosure.

3. An enclosure according to claim 2, wherein said sensing means are connected to an electrical lead extending from the exterior of the enclosure.

4. An air-supported or inflated enclosure comprising:

a rigid base;

a peripheral recess extending around the base;

a strip of flexible substantially water and air impermeable plastics material having one longitudinal edge portion secured to the base;

a cover of open bag-like form formed of a substantially water and air impermeable flexible plastics sheet material having a mouth;

complementary halves of a sliding clasp fastener being secured respectively to a second longitudinal edge of the strip and about the edge portion of the mouth of the cover to permit the strip and the cover to be sealingly but releasably interconnected to form an enclosure;

an inlet and an outlet in said enclosure, each of generally frusto-conical form and being formed of a flexible material; and

means connected to said inlet for inflating said enclosure.

5. An enclosure according to claim 4, wherein said flexible conical outlet changes configuration to discourage egress of air therethrough when the pressure differential between the interior and the exterior of the enclosure drops below a predetermined value.

6. An enclosure according to claim 5, wherein a sub-

Claims

1. An enclosure for an article comprising: a permanently formed ground secured rigid base formed in a manner as to discourage water vapour transmission; a peripheral recess extending around a portion of said base; a strip of flexible sheet plastics material of low water vapour transmissibility having one longitudinal edge portion sealing secured to the base; one half of a sliding clasp fastener extending along the other longitudinal edge portion of the strip; a cover of open bag-like form formed of flexible sheet plastics material of low water vapour transmissibility having a mouth; a second half of said sliding clasp fastener extending about the edge portion of the cover constituting said mouth and sealingly, but releasably, connected to the fastener half on said strip; said base recess being dimensioned to house the portion of said strip adjacent said peripheral recess when such strip is disconnected from said cover to provide protection for that portion of the strip when the article is placed on, or removed from, the base; the arrangement being such that when the sliding clasp fastener halves are interconnected a substantially hermetically sealed enclosure is provided and an environment may be maintained within the enclosure having a lower relative humidity than the ambient air outside the enclosure and yet permits for ready removal of the article from the enclosure.

4. An air-supported or inflated enclosure comprising: a rigid base; a peripheral recess extending around the base; a strip of flexible substantially water and air impermeable plastics material having one longitudinal edge portion secured to the base; a cover of open bag-like form formed of a substantially water and air impermeable flexible plastics sheet material having a mouth; complementary halves of a sliding clasp fastener being secured respectively to a second longitudinal edge of the strip and about the edge portion of the mouth of the cover to permit the strip and the cover to be sealingly but releasably interconnected to form an enclosure; an inlet and an outlet in said enclosure, each of generally frusto-conical form and being formed of a flexible material; and means connected to said inlet for inflating saiD enclosure.

6. An enclosure according to claim 5, wherein a substantially rigid collar extends about said inlet and said outlet and closure caps are provided to permit sealing of the enclosure by engagement thereof with said collars.