Inflatable receptacle

An inexpensive, readily handled receptacle for use in the bulk impregnation of timber by vacuum impregnation is made of flexible fluid-impermeable material and, over parts of its walls, is of double thickness to form closed pockets that can be inflated to form a container of rectangular shape hinged along one of its side faces to provide a sealable opening for loading and unloading. The pockets have a valve for inflating them with air; the receptacle has inlet and outlet ports for evacuating the receptacle and introducing impregnant. Preferably, the receptacle is supported in a two-part rectangular frame hinged along one side face.

In the Complete Specification of our co-pending cognate British patent 
application Nos. 709/77 and 47987/77 (Ser. No. 1589781) there is described 
and claimed an improved method of impregnating with an impregnant in a 
liquid or semi-liquid state a body or bodies made wholly or in part of 
organic fluid-permeable material, which method comprises introducing said 
body or a plurality of said bodies into a receptacle of flexible 
fluid-impermeable material through an opening therein, the flexible 
receptacle being supported by and secured to a substantially rigid 
structure in such a way that the receptacle is held open for the 
introduction through said opening of said body or plurality of bodies; 
sealing the opening in the receptacle to form a substantially fluid-tight 
enclosure; evacuating air and any other fluid from within the fluid-tight 
enclosure so formed and from voids in the or each body housed therein to 
cause the flexible, fluid-impermeable material of the receptacle to 
collapse around the body or bodies; and allowing impregnant in a liquid or 
semi-liquid state to enter the fluid tight enclosure and to flow through 
and impregnate the organic fluid-permeable material of the or each body. 
In the Complete Specification of our co-pending British patent application 
No. 929/78 (Ser. No. 1589782) there is described and claimed a flexible 
receptacle for use in the impregnation with an impregnant in a liquid or 
semi-liquid state of a body or bodies made wholly or in part of organic 
fluid-permeable material, which receptacle is made of flexible 
fluid-impermeable material and has an opening for introduction into the 
receptacle of said body or bodies, re-usable means for sealing said 
opening to form a substantially fluid tight flexible enclosure, at least 
one outlet with an associated valve through which air and any other fluid 
can be evacuated from the receptacle and, separate from the outlet or 
outlets, at least one inlet with an associated valve through which 
impregnant in a liquid or semi-liquid state can be introduced into the 
receptacle. In a preferred embodiment, the receptacle is in the form of a 
preformed container of substantially rectangular shape. 
It is an object of the present invention to provide an improved receptacle 
for use in the impregnation with an impregnant in a liquid or semi-liquid 
state, by the method claimed in the aforesaid cognate British patent 
applications, of a body or bodies made wholly or in part of organic 
fluid-permeable material. 
According to the invention, the improved receptacle is made of a flexible 
fluid-impermeable material which, over at least a part or parts of a wall 
or walls of the receptacle, is of double thickness and forms a closed 
pocket or pockets which can be inflated by fluid impregnation, the pocket 
or pockets being so positioned that when the or each pocket is inflated 
the receptacle is in the form of a container of substantially rectangular 
shape effectively hinged along at least one of its side faces to provide 
an opening for introduction into the receptacle of said body or bodies, 
and the receptacle has means for sealing said opening to form a 
substantially fluid-tight flexible enclosure, at least one port with an 
associated valve opening into the pocket or pockets through which fluid 
can be introduced to inflate said pocket or pockets, and at least one port 
with an associated valve opening into the receptacle through which air and 
any other fluid can be evacuated from the receptacle and through which 
impregnant in a liquid or semi-liquid state can be introduced into the 
receptacle. 
Preferably, the receptacle has at least two ports each with an associated 
valve opening into it, at least one port and its associated valve 
constituting an outlet through which air and any other fluid can be 
evacuated from the receptacle and, separate from the outlet or outlets, at 
least one port and its associated valve constituting an inlet through 
which impregnant in a liquid or semi-liquid state can be introduced into 
the receptacle. 
In one preferred embodiment of the invention, pockets formed by a double 
thickness of flexible fluid-impermeable material extend along each of the 
boundary edges of the receptacle to form, in effect, inflatable ribs 
joined by flexible fluid-impermeable material of single thickness forming 
the side and end faces of the receptacle. The inflatable rib extending 
along one boundary edge of one end face of the receptacle and the 
inflatable rib extending along the corresponding boundary edge of the 
other end face are each sub-divided by an intermediate non-inflatable 
portion which is substantially more flexible than the inflatable ribs 
joined to it and effectively constitutes one end of a hinge extending 
along one side face of the receptacle. The opposite side face and the end 
faces of the receptacle are divided into two separate parts which are 
joined at the hinge and which can be moved apart to provide said opening 
of the receptacle or can be moved together to close said opening by 
pivotal movement of one part relative to the other about the pivotal axis 
of said hinge. The boundary edges of said two parts of the receptacle 
which abut when the receptacle is closed preferably have outwardly 
extending flanges which abut, one or each of the flanges having a layer of 
cellular plastics material or other readily compressible material applied 
to it to effect a fluid-tight seal. Preferably, separately formed means is 
provided for releasably clamping the two flanges together in the closed 
position. Such clipping means may comprise a plurality of resilient clips 
or screw threaded clamps. 
In one alternative embodiment, substantially the whole of the walls of the 
receptacle are of flexible fluid-impermeable material of double thickness 
and may be divided into two or more pockets into which air or other fluid 
can be injected to inflate the walls and form a receptacle of 
substantially rectangular form. As in the previous embodiment, the 
receptacle is hinged along one side face, e.g. between two longitudinally 
extending pockets, the opposite side face and the end faces being divided 
into two parts joined at the hinge. 
In all cases, preferably the pockets are all interconnected so that all of 
the pockets can be inflated by injection of air or other fluid through a 
single port. 
Preferably, in use, the receptacle is supported by and secured to a 
substantially rigid structure, e.g. a lattice framework, built up of two 
parts which are hinged together along an axis extending lengthwise of the 
structure. At least one counter-weight may be provided on one part of the 
structure so that, when the structure and receptacle supported therein are 
in the open position, the counter-weight or counter-weights hold them in 
the open position to facilitate loading or unloading of the receptacle. 
Preferably, one part of the structure has an opening of substantially the 
same cross-sectional shape as one part of the inflated receptacle so that 
the said part of the receptacle can be suspended in said part of the 
structure with its outwardly extending flange resting on the boundary edge 
of the opening in the structure and the other part of the structure 
surrounds the other part of the receptacle and rests on the outwardly 
extending flange of, and is supported by, the other part of the inflated 
receptacle. 
The valves associated with the inlets and outlets of the receptacle 
preferably are non-return valves. 
Preferably, the inlet(s) and outlet(s) are so positioned in the receptacle 
that, when the receptacle is in use, the or each inlet is at or near the 
bottom of the receptacle and the or each outlet is at or near the top of 
the receptacle. Preferably, also, the receptacle has at or near its 
lowermost part at least one drainage port with an associated valve for 
drainage of excess impregnant from the receptacle. 
The receptacle may be formed wholly or in part of a transparent material so 
that progress of the impregnation process can be observed. Receptacles 
made from flexible transparent polyethylene sheet are expecially suitable; 
other suitable flexible materials include butyl rubber sheet.

Referring to FIG. 1, the receptacle is made of flexible butyl rubber sheet 
which, over parts of the receptacle extending along the boundary edges of 
the receptacle, is of double thickness to form pockets 1 which, in effect 
constitute inflatable ribs joined by flexible polyethylene material 2 of 
single thickness forming the side and end faces of the receptacle. 
Strengthening ribs 3 extend substantially parallel to the ribs 1 at the 
ends of the receptacle and are interconnected to the other ribs of the 
receptacle. The inflatable rib 4 extending along one boundary edge of one 
end face of the receptacle and the inflatable rib 4 extending along the 
corresponding boundary edge of the other end face are each sub-divided by 
an intermediate non-inflatable portion 5 which is substantially more 
flexible than the inflatable ribs joined to it and effectively constitutes 
one end of a hinge extending along one side face of the receptacle. The 
opposite side face and the end faces of the receptacle are divided into 
two separate parts 6 and 7 which are joined at the hinge 5. The boundary 
edge of the part 6 has an outwardly extending flange 8; carrying a layer 
18 of cellular plastics material and the boundary edge of the part 7 has 
an outwardly extending flange 9 carrying a layer 19 of cellular plastics 
material. A port 21 with an associated valve opens into one of the ribs 1 
of each part 6 and 7 through which air can be introduced to inflate the 
ribs. An outlet port 22 with an associated valve opens into the receptacle 
near the top of the receptacle through which air and any other fluid can 
be evacuated from the receptacle, and separate from the outlet port, an 
inlet port 23 with an associated valve opens into the receptacle near the 
bottom of the receptacle through which impregnant in a liquid or 
semi-liquid state can be introduced into the receptacle. 
The support structure 10 shown in FIG. 2 comprises a base support 11 and a 
lid 12, each in the form of a lattice framework which are hinged together 
about a pivotal axis 13. The base support 11 has an opening 14 of 
substantially rectangular shape which is bounded by an outwardly extending 
flange 15. The lid 12 has an opening of similar shape which is bounded by 
an outwardly extending flange 16. The lid 12 also has a counter-weight 17 
secured to its rear edge. When the receptacle is mounted in the support 
structure 10, the lower part 6 of the receptacle is supported in the base 
support 11 with its outwardly extending flange 8 resting on the flange 15 
and the upper part 7 of the receptacle supports the lid 12, the flange 16 
of the lid resting on the flange 9 of the upper part 7 of the receptacle. 
As will be seen, when the support structure 10 is pivoted about the axis 
13 to open the receptacle, the counter-weight 17 holds a receptacle in the 
open position for loading or unloading of the bodies to be impregnated. 
In use, the receptacle is positioned in the support structure 10 as 
illustrated in FIG. 2 and the pockets 1 including the ribs 3, 4 are 
inflated to form a container of substantially rectangular shape hinged 
along one side face. The support structure 10 is then pivoted about the 
pivotal axis 13 to open the lid 12 supported by the part 7 of the 
container, the container being held in the open position by the 
counter-weight 17. The container is loaded with the bodies to be 
impregnated and is then closed, the outwardly extending flanges 8 and 9 
being sealed together by resilient clips 25, of which one only is shown to 
render the container fluid-tight. The pockets 1 including the ribs 3, 4 
are then deflated, air is evacuated from within the container through the 
outlet port 22 and, when the container has been substantially evacuated 
and the receptacle has collapsed about the bodies contained in it, an 
impregnant in a liquid or semi-liquid state is introduced into the 
evacuated receptacle through the inlet port 23. On completion of the 
impregnation step surplus impregnant is drained from the receptacle 
through a drainage port 26, air is allowed to re-enter the container and 
the pockets 1 including ribs 3, 4 are again inflated to return the 
container to its substantially rectangular shape. The resilient clips 25 
can then be removed, the container opened and the impregnated bodies 
unloaded.