Note: Descriptions are shown in the official language in which they were submitted.
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Heat insulating device
The present invention relates to a heat insul-
ating device such as a cellular plastic insulating
tube or a cellular plastic insulating plate, with a
tongue and groove-like closure ~ystemO
Heating and cooling system~ are currently
insulated against the lo~s of heat or cold by the
mo~t varied typas of insulating tu~es or insula~ing
plate-q which are designed to be drawn over the tubes
or duct~. The most widely known and currently used
insulating tubes or insulating plates consist of
agglomerate rock wool or gla~s fibre~, or of a wide
variety of pla~tics, e.g. based on ru~ber, synthetic
rubber or other plastics, or of mineral foamsO Tube
insulations are manufactured either as half shells
or as all-round shells. Prefabricated plates o~ the
same material~ are aYailable for in~ulating air duct~.
The tube~ are in ulated by drawing the ~plit tube~
over the tube to be in~ulated or by ap~lyi~g the
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insulating plates laterally to the duct~ to be
insulated. Once the in~ulating tubes have been
drawn over or the insulating plates applied, the
open slit~s) must be closed, so as to ensure that the
insulating member does not come away Erom the tube or
duct to be insulated~ A further rea~on for tightly
cloaing the ~lit is to guarantee perfect in~ulation
and to prevent any moi~ture reaching the system to
(~. be insulated through the slit in the in~ulati~g tube.
Today the method which is u3ually employed to
close thesa slit~ lies in either windi~g ~uitable
matarials around the insulating layer or ~ticking
a self-adhesive strip of a suitable material over
the slit. This applie~ both to the slit extending
in the longitudinal direction and to the joint point~
between the individual insulating tube sections.
These ~lits are frequently al~o clo~ed by applying
a ~uitable adhesive to the surface~ of the joint
points when the tubes are laid and then manually
pre~sing them together, until the adhe~ive holds.
There are also insulating.tubes or plate~ which are
provided in the factory with a ~elf-adhe~ive ~krip,
half of which i applied to the tube and the other
half of which i~ provided with a prot~ctiv~ foil~
The per~on laying the ~ube~ xe~oves the protsc~ive
layer on the one hal~ o~ thæ adhesiv~ strip, draw~
ths in3ulating tube over the ~u~æ ~o be inYulated
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and then presses the projecting foil, now free of
the protective layer, on to the opposite in~ulatiny
tuke section so as ~o tightly clo~e the slit. There
are also insulating tube~ which are provided with a
walded-on, so~called pla~tic zipper.
However, the~e closing sy~tems which are
usually used today have considerable disadvan~ages,
the following in particular:
(a) There i~ no guarantee that the per~on laying
~he tubes will always work ~n a careul manner.
There are therefore fre~uent ca~es o~ incomplete
~urface adhesion of the joint points at the slit,
; thu~ leaving open areas. This kind of adhesion at
the joint point~ of the slits by applying adheslve
materials also gives rise to a hardaning proce~s,
cau~ing the formation of a cold or heat bridge,
which ~t thi~ point i~ a be~ter conductor than the
~~, actual insulating material and thus c~nducts heat
or cold to the out~ide.
20 ~b) When adhesive foils are u~ed to clo~e the tube
it frequently happen3 that the joint point~ o~ the
tube slit~ are not firstly pressed completely together,
thu~ causing ~o-called air brid0~3. ~his, in turn,
result~ in cold or heat ~ridge~O
25 t c ) Laying the t:ube9 using the~e clc:~sing sy~tems
i8 e~pen~ive, a~ ~he pxocedure i s relatively slow.
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~d) It often happens that insulat.ing tubes or
plates become covered with dust at the building site.
Should the du~t not he completely removed before the
slit is closed, the self-adhesive foil will not
adhere co~pletely and open ayain after it has been
laid~
[e) It is al~o known that insulating tubes are
clamped together by plastic or metal clamps. ~hi3
( type of closure entails the danger of even larger
air bridges fonming. Sati3fa&to~y insulation aannot
therefore be guaranteed.
In order to avoid these di~advantages it was
proposed some years ago, in the DE-PS 25 03 42S, to
form the tube slit according to ~he groove and tongue
principle, in which the groove and tongue could he
provided with undercuts, e.g. of the dovetail type,
which would then act as a snap closurè. However,
(~ cellular plastic insulating tube~3 with this kind of
groove and tongu~ arrangement have not as yet been
20 put into practice, probably because these groove and
tongue ~ystems cannot functioxl a~ I'Anap closure "
where cellular materials are involvad. Thi~ i~
~ecause in the ca~e of hard cellulax materials the
undercuts are broken off upon joining w~ile in the
ca~e o~ ~le~ible cellular mat~rials the tongue pro-
~ided wi~h undercut3 is not sufficiently ri~id to be
insarte~ in the groove provided with undercu~s~
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An object of the present invention is therefore to
provide a heat insulating device such as a cellular plastic
insulating tube or plate, with a groove and tongue closure
system whi~h can actually be put into practice and in which the
groove and tong~e system functions as an actual snap closure.
According to the invention the tongue is more rigid or
stiffer than the material forming the receptacle therefor.
Thus according to the invention there is provided a
cellular plastic insulat.ing member of a flexible plastic foam
lQ material for thermally insulating a conduit, such as a pipe,
duct or the like, the member having a closing line extending
longitudinally along the conduit, along which line facing
longitudinal surfaces of the insulating member are joined
together, a closing system located along the closing line and
comprising a groove and a tongue, the groove comprising a
longitudinally extending groove formed into the material of the
member along at least one side of the line~ the opening of the
groove, viewed in a transverse cross section, being smaller
than the dimension across certain interior portions of the
groove, also viewed in transverse cross section, the tongu~ of
the closing system operatively connected to the side of the
closing line other than the side having the groove, the tongue
having a portion, viewed in transverse cross section, which is
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larger than the opening of the groove, and the tongue being
undercut, of smaller dimension closer to the side of the
insulating member to which it is operatively connected, such
that the tongue and groove snap fit into engagement with each
other, and the tongue being stiffer than the material forming
the groove.
More particularly, the present invention therefore
provides cellular plastic insulating tubes or cellular plastic
insulating plates of a flexible plastic foam with a tongue and
groove closure system arranged along a longitudinal axis, in
which the groove and tongue are provided with undercuts,
wherein the tongue consists of a more rigid or stiffer material
than the material forming the groove, or, if the tongue
consists of the same material as the insulating cellular
material, the tongue is reinforced or stiffened.
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The tongue and groove may be formed from ~he
foamed material in which case the ton~ue may be pro-
vided with a reinforcing coating or an inner re
inforcement7 Alternatively ~he tongue may be made
of a material which is more rigid or sti~fer than
the ~oamed material.
In the latter case a plastic foam profile, for
axa~ple, the density of which is, for example 25 to
( 100% greater than that of the cellular pla~tic
in~ulating tube or the cellular plastic insulating
plate, i~ welded or glued to the ~urface opposite the
groove. An embodiment of thi~ kind i5 preerred
according to the invention. However, in~tead of the
plastic foam profile, it is also possible to weld or
glue on a closed plaqtic hose or a pla~tic hose open
in ~he longitudinal direction, i~ thi~ is sufficiently
rigid. The ~ame applie~, ~or example, to a closed or
( longitudinally open plaqtic, metal or glas~ ~ibre`
tube which, after welding or glueing on, produces
the requi red tongueO For example, a closed or open
aluminium or copper tube could be used as khe tongue,
if the insulating tube or the in~ulating plate i~ to
have a certain degree of rigidity~ Furthenmore, t~e
open ox ~1O3ed tubes, applied as a tongue, eould, if
appropria~a, be used ~o accommoda~e lead~, e ~ g~
i~trument leads or record lines.
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The plastic foam profile described above and
used as a tongue, as well as the pla~tic ho~e~ and
the various clo~ed or open tube~, can al~o be pro
vided with a continuous or broken or triansular
notched lug which, for example, ha~ been inserted in
a slit previously made in the plastic foam in the
surface oppo~ite the groove and then glued. In the
case of plastic foam pro~iles khe lug can Qxtend into
the proile, the rigidity of which i5 then further
increased by the lug, ~us facili~ating the insertion
of the pro~ile in the groove.
It is al~o possible to use an appropriate
double profile (solid or hollow, clo~ed or open),
possibly connected by way of a com~on lug, in cases
where, according to the invention, the in~ulating
tube or the insulating plate compri~es an additional
~ groove instead of the tongue, so that the double
- (` profile engage~ on both sides in the opposite grooves
in th~ slit ~urface~.
Should it be de~i~able, in particular ~a~es,
for the groove and the tongue to be glued toyether,
the adhe~ive can be applied to one of the groove
~urfaces and/or the tongue surface~, po 3ibly a~ a
self-adhesive 3trip with a removable protactive oil
which, for example, can con~i3t of paperO The
adhe~ive can of coursa al~o be a fu~ion adhe~ive,
for 2xampl2 in the for~ of an applied foil or non~
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woven 3trip which, when the insulating tube~ or
plate~ are laid, i activated by a hot air device
and pre~ed together. ~Iowever, magnetic lacquer can
be u~ed in~tead of fusion adhesive. It is of course
pos~ible to glue the tongue and/or the groove in the
usual manner by means of any other conventional
adhesives.
Should the groove and the tongue con~i~t of the
( ~ame material and the ~ongue be provided with a
reinforcir~g coating, it i9 po~sible, during the con-
tinuous production of the insulating tubes or plates,
to firstly make a groove-tongue-~lit along the longit-
udinal axis of the insulating tube or plate in one
working ~tep, particularly if the tubes or plate~
consi~t of ~henmoplastic foam. This 9iit can be of
any desired shape, angular, round, oval, etc. and i~
formed by means of a simple heating wire or bar, Xn
( the case o~ an insulating tube, it is then opened up,
the tongue i~ provided with the coating, which is
left to harden, and the tongue is finally in~erted
in the groove. When producing the groove and khe
tongue care should be taken to en~ure that the temp-
erature of the heating wixe or bar corre~pond~ pre-
cisely to the melting point of the extru~ion material.
A suitable thenmo~tat can be u~ed for this purpo~eO
The temperature control mu~t be rsgulated in xelation
to the melting point o~ the material and the speed of
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passage~ In~tead of usillg hQating wire or bars, the
~roove and tongue can al~o be produce~ by ultra~onic
systems or laser beama. Care should ~e taken, when
producing the groove and tongue, in conjunction with
the longitudinal slit, to ensure that, e.g. not ~oo
much material is melted away by overheating the heat-
ing wires or bars.
According to a further pre~erred embodiment of
the invention, it i5 al~o possible to rein~orce the
tongue produced as described above by bisecting the
tongue in the longitudinal direction as it is pro-
duced and letting the bisector slit project beyond
the tongua into the tube shell carrying the tongue.
A reinforcement strip of appropriate size and provided
with adhesive on both sides or heated to welding temp-
erature i~ then inserted in the bisector slit thu~
produced and ~irmly connected by pres~ing to the tube
( shell and the two tongue part~O The reinforcement
strip can ~e smooth or, in order to increase rigidity,
corruga~ed at right angle~ to the lo~itudinal axi~,
~o that it can easily adapt to any bend~ in the tube.
In the ~ame way a~ the lug de~cri~ed abova, the
reinforcement strip can be provided with rece~es or,
or example, be fonmed as ~ corrugated punched tapeJ
However, in many ca~es it may be particularly advantage-
ou3 to ~irmly insert a relatively rigid pla~tic ~rand
ben~ in a contlnuou~ly zig-zag manner or an appropriately
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bent metal wire in the bisector ~lit instead of khe
reinforcement strip. rrhis ensures on the one hand
tha~ the tongue, particularly in the case of ~on~les
undercut at the base, is of the required rigidity,
5 so that it can be in~erted in the groove, and on the
other hand that the insulating tube can ~till be
slightly bent.
However, instead of inserting a finished
reinforcement strip or wire etc., it i~ also po3~ible
to produce ln situ in the bisector slit projecting
into the tube shell a reinforcement or stif~ening
by using a hardening plastic, which at the same time
reinforce~ the bisector slit following finm adhesion
or hardening. Suitable plastics for this purpose are
known to persons ~killed in the art.
The tube ends are preferably forme~ such $hat,
particularly in the case of fairly thick tubes, they
( comprise an annular groove at one end and a corre~-
ponding annular tongue at the other, which annular
tongue can be formed according to the ton~ue of the
invention arranged along the longitudinal axis, both
a3 regards shape and reinforcement or stiffening.
However, in~tead of the annular groove and
annular tongue, one tube end can be externall~ milled
off, e.g. up to half the thickness of the in~ulating
wall tube, and the other end can be coxrespondingly
internally milled o~f, 50 as to ob~ain an avsrlap
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pl~g-type connection, which can of cour~e al~o be
glued together in the same way as the longitudinal
groove-ton~le system and the annular groove-tongue
system .
S In order that the invention may be more fully
understood various embodiment~ thereof will now be
described by way of illustrative example with refer-
ence to the ~ccompanying drawing~ wherein,
( Figure~ 1 to 9 are transver~e sectional view~ of
insulating tubes according to the invention;
Figures 10 to 17 are sectional ~iews of plates
according to the invention,
~igure 18 is a longitudinal section of t~o tube3
according to the invention with a longitudinal
stepped coupling and
Figures 19 to 21 are secti onal views of further tube~
accordiny to the invention.
(~~ In tha Figures the reference numbers indicate
the following:
1 ~lexible cellular plastic insulating tube
2,2'.tongue
3,3' groove
4 reinforcement 3trip
fusion adhesive
25 6 ~lexible cellular pla3t.ic insulating plate
7 l~g
8 double profile
:~ 9 air shaft to be insula~ed
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Plgure 1 i5 a cross-sectional view o a flexible
cellular plastic insulati~g tube 1, provided with a
slit in the longitudinal direc~ion, with the welded-
on or glued-on ~ore rigid or stiffer plastic foam
tongue ~ according ~o the invention, which engages
in the groove 3.
Figure 2 i 9 a cross- secti~nal view o a part
: of a flexible cellular plastic insulating tube 1
wi th the welded-on or glued-on tongue 2, opan in the
longitudinal direction.
Figure 3 is a cro3s-sectio~al view o~ a part of
a flexible cellular plastic in~ulating tube 1, e.g.
a polyethylene tube, with hollow, welded-on or glued-
on tongue 2 which i9 more rigid than the tube 1.
15Figures ~ - 6 are cross-~ectio~al view~ of a
flexible cellular plastic insulating tube 1, wherein
khe tongue 2 is provided with a reinforcement ~trip
: ( 4 to make it more rigi~ than the material defining
. the groove 3. The tongue 2 i~ shown recei~ed in the
groov~ 3,
It will be appreciated that in the foregoin~
Figuxes, the tongue 2 can be snap-fitted into the
groova 3.
Figure3 7 - 9 are cross-sectional detail~ of
flexible celiular pla~tic in~ulating tu~es 1 with
the ~roove~ 3, which are partly prsvided with a
~usio~adhe~iv~ 5.
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Figures 10 - 13 are cxo-Qs-~ectional views of
two longitudinal side~ of two flexible cellular
pla~tic in~ulating plates 6, one of which iQ provided
with ~he groove 3 and the other with the corresponding
welded-on or glued-on tongue 2, which can consi~t of
the materials mentioned in the above deseription.
Figure 14 is a crosq-sectional view of two
lon~itudinal sides of two flexible cellular plastie
(~ insulating plates 6, one of which is provided with
the groove 3 and the other with the tongue 2. The
tongue 2 bears a lug 7, which is glued into a slit
in the flexible cellular plastic insulating plate 6
Figure 15 is a cross-sectional view o~ the
cellular plastic insulating plates 6, which are
provided with grooves 3 and in which is inserted
the double profile 3, whic~h can be solid or hollow,
cloqed or open, as the double tongue. These double
profiles 8 ean al~o ke u~ed for flexible eellular
plastic in~ulating tubes 1, in whieh ease however
the centre point~ of the two profiles Qf the double
profile 8 preferably lie on a circular line corres-
ponding to the mean eircumference of the respeetive
eellular pla~tic insulating tube 1.
Figure 16 is a eross-~ectional view of the
longitudinal edges of two eellular pla~tic insulating
plates 6 provided with a groove 3 and a tongue 2,
which ha~ been cut ou~ o~ the cellular pla~tic
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insulati~g plate 6 and is provided for reinforcement
purpo~e~ with the reinforcement strip 4, which pro~
jects from the front end of the tongue 3 into the
flexible cellular pla~tic in~ulating plate 6.
Figure 17 is a cross-sectional de~ail of an air
shaft 9, which is surrounded by the flexible cellular
plastic insulating plates 6, the groovs 3 and the
tongue 2 fonming a diagonal connec~ion and the tongue
( 2 comprising a reinforcement strip 4, which projects
into the flexible cellular pla~tic in~ulating plate 6.
Figure 18 is a longitudinal section of two ends,
one inserted into the other and appropxiately milled
off, of a flexible cellular plastic insulating tu~e 1.
The cellular plastic insulating tubes ~hown in
Figures 1 to 3, for example, are -~moothly cut through
at the top on the production line during the contin-
uous manuacture of the tube~, then pressed open by
several centimetre~ at the cut point by a "holding
open" device. A spherical cutter then cuts a groo~e,
accurate to the millimetre, in one side of the tube
wall. A pla~tic or cellular plastic pro~ile is then
continuou~ly applied a~ the tongue to the opposite
~ide of th~ slit b~ adhesion vr thenmal welding~ The
plas~ic or cellular plas~ic profile is continuously
rol~ed off a roll and appliad. Once the groove ha~
been made and the ~ongue profile applied, the tube
i~ clo~ed again by ex~exnal pre~ure and con~inu~
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along the line. It is not absolutely essential or
the groove and the tongue to be round. They can be
of any desired shape, e.g. oval or angular. Poly-
olefinea, e~g. polyethylene or polyurethane or other
S quitable plastics can be u~e~.
According to a further preexred embodiment of
the invention, the groove and the to~ue, arranged
along the longitudinal axi~, can also be ~onmed as
( an ove~lap system, as shown in Figures 19 to 219
Other appropxiate overlap shapes are of cou~se pO~3-
ible in this case. The overlap sy~tems shown in
Figures 19 to 21 represent a quasi double groove-
double tongue-system, in which the tongues in the
various embodiments described above can be reinforced
and provided with fusion adhesive or magnetic lacquer.
However, various overlap systems according to the
invention can also comprise a tongue or tongues
~` without reinforcement, as may be the case, for
example, in the embodiments according to Figure~ 19
and 20, if ~he cellular material is not too 1exible.
Figures 19 to 21 are cro~-sectional views of
the arrangement of a double tongue-double groo~e-
overlap ~ystem~
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