Note: Descriptions are shown in the official language in which they were submitted.
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The invention relates to a process for treating wood in which a wood
preservative as inserted into one or more recesses made in ~ood,
whereupon these recesses are closed ou-twardly.
The treatment of wood with a wood preservative aims at protecting
the wood preventively or curatively against attack by moisture, micro-
organisms (for ins-tance Basidiomycetes, Ascomycetes, Fungi Imperfecti,
etc.), insects (for instance Hylotropes bajulus L., Anobium punctatum,
Lyctus brunneus Steph., etc.), termites (for instance Calotermes
flavicollis, Reticultermus Luciferus Rossi) and bacteria.
A similar process is generally known. Preferably a capsule is used.
The process followed is then that first a hole is drilled in the wood,
subsequently a glass capsule with the wood preservative is inserted
into it and finally the driliing hole is closed with a plug, which is
applied in it in a recess, in result of which the capsule breaks and
its contents are freed and spread in the wood.
A drawback of this process is that wooden beams, window-frames, etc.
forming part of supporting structures or wooden elements which are
regularly charged, are weakened as a consequence of the remaining
holes.
Another drawback is that the user of the capsules when breaking
the capsules may come into contact with the con-tents thereof.
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This may rappen because the plug does not close well or because
the capsule is not positioned deep enough in the shallow drilling
hole.
I t has a I so been suggested to app I y a wat0r
repel I Ing agent In the recess.
In European patent application 81 108689.1 (published under
No. 0050839) it is elucidated that the use of a water e~pellent
10 agen-t gives very great problems in practice with wood aiready
painted. Not only is the expulsion of moisture strongly interfered
with, but there also is a chance that locally the moisturê content
will increase as a xesult of the water expellent agent. If it
rises above the cri.ical value of 21 % a chance of wood attack by
15 developent of wood decay fungus is very great. Also~ the paint
system can be damaged as a result of moist accumulation on the
surface o~ the wood. That is why in the European patent
application it is proposed to apply a solution of a water binder
in an organic solvent in recesses of a wooden product. In result
20 hereof the objection of moisture accumulation is removed, but the
application of a water binder has the drawback that the active
substances which have to prevent wood attack, are locked up, in
consequence of which a good penetration hereof in the wood is
reduced. Consequently, also here the object aimed at, to wit
25 prevention and combating, resp., of wood attack by micro-organisms,
insects and bacteria is not fully achieved.
The invention provides a process which meets the above-mentioned
drawbacks.
According to the invention in a process as mentioned at the
beginning a solid material is applied in the recess together with
the wood ?reservative in such a way that this solid material at
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least partly fills up the recess, said solid material having a
reinforcing effect upon this wood when it absorbs water and
expands in consequence thereof and/or when a permanent pressure
is exerted upon it.
Preferably, also wood is applied having a lower water content
than the wood treated, most preferably resin-free splint-wood or
heart-wood. Splint-wood is young wood and has a less resin-rich
cell structure than has for instance heart-wood. This property is
of importance in view of the absorption capacity of the wood and
the capacity to absorb free liquid. By applying wood for this
which has been freed from resins and other fillers, this êffect
is not only strengthened, but it is also prevented that chemical
reactions between the wood preservative substances and these
resins and other fillers can occur.
It is preferable to apply the wood material that is applied in
the recesses of the wood to be treated in such a way therein that
the wood preservative present therein is released in the direction
of the fibres of the wood material applied. - So that means that
the fibre direction of the wooden plug is the radial direction so
that the fibre direction is the same as that of the surrounding
wood. This does not only give the big advantage that the delivery
of the wood preservative to the surrounding wood is accelerated,
but also that it also distributes itself more uniformly in the
surrounding wood. In consequence the chance of problems in
painting the wood over is reduced.
Owing-to the process according to the invention a material being
applied in the recesses together with the wood preservative having
a lower water content that the wood treated, the wooden plug will
start absorbing water after application and in result expand more
than the directly surrounding wood shrinks. In result a reinforcing
3~
eîfect is exerted upon the surrounding wood.
It is generally known that by nature wood contains water. This
water can be present in two forms, to wit bound to the cell walls,
the so-called inhibition water, and as free water in the cell
cavities and vessels. This water is usually indicated as capillary
or occlusion water. This water is present only if the cell walls
are completely saturated. ~hen drying wood first the free water
disappears from the cell cavities. In for instance deal the
moisture bound, in other words the inhibition water, amounts to
about 29 ~ at a maximum. In drying at a relative humidity of 80 a
a wood hu~idity of about 17 % is created, at which a shrin~age of
1.25 ~ in radial and 0.1 ~ in the ribre direction occurs.
A deal pi~g, which is pxovided with a wood preserving organic
agent anc a moisture content of about 10 a, will expand after
application in the wood to be treated which is in constant contact
with the c?en air and in result thereof has a higher moisture
content. rn addition to the reinrorcing effect this has on the
surroundieg wood also a stabilising effect occurs because the
moisture content o~ the plate treated decreases. This is in
particular important for critical spots sensitive to wood attack.
For if here the moisture content will surpass 21 a the chance that
the wood aecay fungi most occurring in Europe, such as
Polystict-s versocolor, Coniopohra Puteana, Gloephillum tradeuy
are develo?ed, is very great.
The invencion also relates to a product for treating wood, comprising
a wood preservative, optionally packed in a wrapping of prctective
material, wllich wrapping is smashed up upon exertion of pressure
from insi~e, said ?roduct being characterized in that that an
absorbing material having a moisture content below 16 ~ which
expand on absorption of water, is present. It is preferable to have
the absorblng materlal conslst of wood, most preferably spllnt
wood. Also cork Is consldered because It Is a blt comPresslble.
For If no protec~ing wrapplng Is applled It Is advantageous to
have the product accordlng to the Inventlon whlch Is applled In a
recess of wood to be treated, taper a blt, so that the dlameter
of the portlon of the plug whlch closes the recess present In the
wood to be treated from the outslde Is somewhat larger than the
bore-hole. For In consequence thereof the plug Is anchored even
more flxedly and no wood protectlve agent or glue whlch Is pre-
sent In the plug, can escape along the plug. If one wlshes toglue the plug In the recess, one applles glue at the head of the
plug and/or along the plug. By provldlng the plug wl th a recess,
any excess of the glue Is caught hereln~ so that the glue cannot
come Into contact wlth palnt applled on the outslde of the plug.
16 In result thereof dlscoloratlon of the palnt Is prevented.
In a preferred embodlment of the wooden plug one also
sees to It that the portlon of the plug applled In the recess
last Is not oversaturated wlth the wood protectlve agent. Thls
Is of great Importance In applylng the plug for the sake of secu-
rlty of the users. Also, thls has the great advantage that the
wood protectlve agent cannot splash or run off after openlng the
packlng or can run off In open seams of wlndow frames.
In order that one does not meet wlth problems when
palntlng the wood treated over, the Impregnated plug can be pro-
vlded on one end wlth an Impermeable medlum, for Instance a gal-
vanlzed wood screw, whlch closes the whole borlng hole openlng
when applled. It Is also posslble to apply a non-Impregnated
plug on one end whlch by means of a compresslble sealIng dlsc for
Instance of alumlnlum foll Is separated from the Impregnated por-
tlon.
The Inventlon Is further Illustrated by way of the
accompanylng drawlngs In whlch:-
Flg.s 1 to 9 are vertlcal sectlons through plugsaccordlng to varlous embodlments of the presènt Inventlon.
The plug accordlng to Flgure 1 substantlally conslsts
of absorbent materlal havlng a low water content, for Instance
cork, wood flour, wood shavlngs, etc. Portlon 1 Is not Impreg-
nated wlth a wood protectlve agent.
Portlon 2, however, Is Impregnated wlth the wood
preservatlve. Both portlons are mutually separated by a fllm of
compresslble materlal 3, whlch may for Instance conslsts of a
remalnder of the packlng materlal In whlch the plug was packed
before use or of glue or resln. Partltlon 3 prevents the wood
preservatlve In the Impregnated portlon 2 from penetratlng In the
non-lmpregnated portlon 1, when In applylng the plug In a recess
of wood pressure Is exerted on portlon 1. If In the absorbent
materlal a glue Is present, the glue runner 4 sees to It that any
excess of glue present cannot escape outwards.
When the plug of Flgure 1 Is Inserted Into a recess and
a pressure Is exerted from outslde, the Impregnated portlon
clamps In that non-pregnated portlon.
In the embodlment accordlng to Flgure 2 the connectlon
Z5 between the non-lmpregnated and Impregnated portlons Is realIzed
by means of a galvanlzed headless Iron screw 5. Also a screw
made of plastlc materlal, for Instance polyurethane, Is con-
sldered.
In the embodlment accordlng to Flgure 3 the connectlon
between the non-lmpregnated portlon and the Impregnated portlon
of the absorbent materlal Is effected by means of a bayonet
catch. By uslng a sprlng 6 on the InsIde and a compressIble
packlng, both portlons can expand wlthout the total length of the
plug belng Influenced. Thls Is of great Importance In vlew of
the stablllty of the plug
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in the wood and for a paint layer applied thereover.
In the embodiment according to figure 4 use has been made of a
plastic compressible glue layer 7. Because hereof the packing
material 3 closing the impregnated portion need not be compressible.
In the embodiment according to figure 5 use is made of a glass
capsule 8, to which a non-impregnated plug 1 has been screwed. A
sealing ring 11 made of for instance cork with aluminium foil or
rubber sees to it that the wood protective agent in the impregnated
portion 2 cannot diffuse in the portion 1. When smashing in this
capsule the glass wrapping breaks and the broken glass and' the
absorbent material are impressed in such a way that the whole
boring hole is filled up completely all the same. After some time
the absorbent mass will expand by moisture absorption from the
surrounding wood and extra reinforce the whole.
Figure 6 also relates to an embodiment with a glass wrapping. In
this embodiment a galvanized iron screw 9 is present. When placing
the capsule the screw will smash the glass wrapping and will in
consequence be anchored fixedly in the surrounding absorbing
material. This embodiment has the advantage that no glue need be
used, whilst moreover no wood protective agent can escape along the
screw. There is no chance of splashing when applying the capsule
either. The whole can be finished with a wood repair agent, so that
also the substrate for the paint system to be applied over it is
fully suitable for applying the paint over it.
In the embodiment according to figure 7 use is only made of an
impregnated plug 10 which is reinforced with nylon or galvanized
gauze. Also this offers the advantage that no contact between the
wood protective agent and the user can take place. The layer of
sealing material 3, which for instance can consist of aluminium
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foil reinforced with paper prevents the wood protective agent from
penetrating towards the paint on the outside of the wood treated.
This effect can even be reinforced by finishing the whole with a
two-components glue, which is impermeable to polar and apolar
organic liquids.
In figure 8 use is again made of a galvanized iron screw, which is
screwed in the impregnated portion of the absorbent material. By
applying on the other end of the compressible material a
compressible foil 3, the plug can expand without the total length
of the whole product being longer. This foil does see to a
reinforcement of the whole.
In the embodiment according to figure 9 use is made of a flat
screw 9 of galvanized iron or a plastic and a closed capsule of
glass. The capsule is surrounded by a thin foil of plastic, for
instance polyethylene foil or of polyvinylchloride foil. The whole
is constructed such that after application of the glass capsule
in the boring hole the capsule can be smashed by screwing the
screw on. In case of a correct selection of the contents of the
capsule, to wit by seeing to it that an organic liquid is present
therein, in which the foil of plastic surrounding the glass capsule
initially, dissolves, the wood protective agent can penetrate the
wood to be protected.
Instead of with a plastic foil ,he capsule with screw can also be
wrapped in nylon or galvanized gauze (8). Also this packing need
not be removed, no more than a wrapping of plastic ~oil before
applying the capsule in the boring hole. This embodiment has the
advantage over the known capsule, the wrapping of which consistS
wholly of glass, that a-ter inserting the capsule into the boring
hole, the screw applied as closure is inserted into the boring
hole simultaneously with the capsule. ~hen using the known capsule5
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after application of the capsule for closing the boring hole a
closing plus is to be applied in a separate act. It then could
happen that such a plug was inserted after it had been forgotten
to apply first the glass capsule. This is impossible when
applying a closing screw, which is applied integrally with the
capsule.
Figure 10 relates to an embodiment in which use is made or a unit
consisting of a sealed capsule (8) of smashable material, for
instance glass, filled with a solution of a wood preservative and
a plug (1) of material impermeable to wood preservative, for
instance heart-wood, fixedly connect herewith for instance by
glueing. If the plug consists of hardwood, in particular of
European oak, the plug moreover does not deform in smashing. When
the plug is internally provided with a cavity (12) into which a
protruding portion (13) of the sealed capsule fits, yet a relative
large amount of wood preservative can be taken up into the unit,
although a large part of the length of this uni-t is taken by the
plug. This is in particular of importance when treating wood
structures having a smaller thickness, for instance window-frames.
In general it is advantageous to select the wrapping material of
the capsule, for instance the glass such that it does not transmit
ultra-violet light. This promotes the keeping qualities of the
wood preservative present in it.
Figure 11 relates to a variant of the connection of the plug with
the capsule according to figure 10. Between the plug (1) and the
collar of the capsule 8 there is an elastic ring 14, for instance
of rubber or plastic, whose lower side has an opening of a somewhat
smaller diameter than the drilling hole. Preferably this ring is
O-shaped. The presence of this ring sees to it that the plug (1)
is automatically centered, which is important in automized
production. The ring may not be too thick, + 1 mm, because other-
wise the ampulla can hardly be broken.
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The plug 1 generally acts wa-ter controlling. After application it
absorbs water, but after the wood preservative has penetrated into
the wood to be protected, the plug can again release water, if the
surrounding wood dries up.
It is also possible to process the products shown in figures 1-10
into dowels made of wood, e.g. beech, European oak or merbau wood.
Dowels are used for accomplishing pin hole connections between
wooden paxts, e.g. of window-sills, windows and do~rs. In general
such dowels have a himidity content of less than 106 by weight.
If the dowels known per se (vide e.g. figure 12) are provided with
a pre-drilled recess, which possibly is extending over the entire
length thereof a product according to one of the figures can be
introduced into that recess, whereupon the recess is sealed by
a wooden plug (or two plugs if the recess is extending over the
entire length). This is shown in figure 12. In this figure 15
represents a dowel into which a recess 16 having a diameter of
e.g. 16 mm and a length of 100 mm has been drilled over the entire
length. Into said recess a product, e.g. according to figure 10,
has been introduced, while the open ends of the recess 15 are
sealed by wooden plugs 17, which are provided with guiding edges 19.
As soon as the dowel is applied for connecting wooden parts the
plugs are pressed inwardly. The dowel is longitudinally provided
with small grooves for distributing the glue, by means of which the
dowel is glued in the wooden parts. The wood preservative is
distributed into the surrounding wood immediately when the ampulla
is smashed when the wooden plugs take up water. This can take place
via the dowel or through the plugs, dependent on the kind of
material chosen, e.g. the kind of wood or synthetic material,
combined with each other or not.
It is also possible to provide the plug(s) beEorehand with recesses,
so that the wood preservative can spread more easily or earlier
in the surrounding wood.
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It appeared to be advantageous, particularly when placing the
ampulla in horizontal bore-holes in the wood, to provide the plug
made of wood or another material with parallel pitches. For if an
excess of pressure develops at a high degree of filling of the
ampulla it could happen that some liquid is pressed outside along
the plug. When parallel pitches are present in the plug in each
pitch a separation between gas and liquid takes places, the gas
being gathered in the upper portion of each pitch when the plug's
position is horizontal. So the gas can escape from the upper portion
of the horizontal plug along the plug, so that the excess of
pressure disappears and the danger of liquid filtering through is
prevented. To elucidate this reference is made to figure 13. Figure
13 relates to a plug with parallel pitches 23 which are bevelled
in respect of the plug axis. Besides an extra provision is made in
this plug in order to prevent filtering through of liquid after
placing the ampulla in the wood to be preserved. The plug is
provided with a stopping edge 20 having a diameter which is somewhat
larger than the other part of the plug. In order to apply the above
described plug a special, adapted form of the bore-hole is required.
This can be obtained by drilling a hole first to standard depth,
after which the first part of the bore-hole is drilled to the
desired size with a drill having a larger diameter.
In the shown plug under the stopping edge (20) an annular space 21
is left blank to take up glue, when the stopping edge is provided
with a layer of adhesive to glue the ampulla in the wood to be
preserved.
The hollow space 22 has been left blank to insert the upper portion
of the ampulla therein.
Finally, it is remarked that the expression wood preservative is to
be understood in the broadest sense. Also agents, which as such do
not exert a killing effect on living organisms, but see to a medium
in which living organisms cannot multiply are meant. For instance,
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a solution of paraffin in an organic solvent can be applied. When
this solution penetrates into the spaces between the wood fibres
and the organic solvent evaporates partially, the paraffin remains
in the spaces, in result of which no living organisms can develop
therein.
