Note: Descriptions are shown in the official language in which they were submitted.
This is a division of Application 275,977 filed
April 12~ 1977.
:
FIELD OF THE INVENTION
The present invention relates to apparatus for manu- -
facturing heat insulating material from an uncured, strip-shaped
felt of fibres containing a heat hardenable bonding substance.
DESCRIPTION OF THE PRIOR ART
At the present time, it is common practice to provide
preformed cylindrical thermal insulation coverings in one, two
or three pieces for ho~ and cold pipes, such coverings being
commonly referred to as "pipe insulator sections".
Various production processes are employed for manu-
; facturing such thermal insulation coverings. However, these
prior methods have the disadvantage that the pipe insulator
sections must each be shaped and dimensioned to closely fit a
`l corresponding pipe outer diameter. This necessitates the manu-
facture of the pipe insulator sections in a plurality of differ-
ent si~es, which necessarily results in correspondingly high
manufacturing, storage and transportation costs.
Moreover, the storage and manufacturing costs of these
prior art pipe insulator sections are further increased by the
fact that, since the sections are rigidly preshaped to fit the
pipes, packages containing the sections are necessarily bulky
and wasteful of space.
.
It has also previously been proposed, for example in
United States Patent No. 2,949,953, issued August 23, 1960 to V.
DiMaio et al, and United States Patent 3,012,923, issued December
12, 1961 to G. Slayter, to provide a pipe insulation material in
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the form of a strip of fibrous material in which the fibres ex-
tend in the direction of the thickness, i.e. transverse to the
length and the width, of the strip. Such pipe insulation
material can be wrapped around a pipe so that the fibres of the
insulation material extend substantially radially of the pipe.
However, as will be appreciated by those skilled in
the art, fibrous insulating material has a greater resistance to
the passage of heat therethrough in the direction transverse to
the fibres than in the direction extending longitudinally of the
fibres. Consequently, insulating material in which, when the
material is installed on a pipe, the fibres extend radially of
the pipe pro~ides relatively poor heat insulation as compared to
insulating materials in which the fibres extend transversely of
the direction of heat flow.
The aforementioned United States Patent 3,012,923
also proposes the manufacture of a fibrous heat insulating
material by forming a series of corrugations or pleats in a mat
. .
of mineral Fibres bonded to form a Elexible mat, the mat being
cured prior to the formation of the corrugations or pleats, and
the latter being compacted, a backing sheet being adhered to one
side of the corrugated mat to hold the corrugations together.
This backing sheet forms the interior face of the insulating
material, i.e. it is placed against the outer surface of a pipe
when the insulating material is installed on the pipe. This
prior insulating material has the disadvantage that, since the
corrugations are not adhered or bonded to one another, the fibres
in the regions of the corrugations or folds opposite from thosé
regions which are adhered to the backing sheet expand and cause
the insulating material to curl, which makes it difficult,ifnot
impossible, to pack the insulating material in flat packages for
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shipment. Also, the provision of the backing sheet on the side
of the insulating material which, in use, is adjacent the pipe
to be insulated is disadvantageous firstly because the adhesive .. ...
securing the ba.cking sheet to the insulating material is exposed
to the heat of the pipe, which may be sufficiently excessive to
cause the backing sheet to cease to adhere to the corrugated mat,
and secondly because a second, exterior jacket is required when
the insulating material is in use to protect the insulating
material, in accordance with normal practice in the art, from
ambient moisture, dust etc. ~he on-side provision of the ex-
terior jacket adds additional expense and unacceptabl~y compli-
cates the fitting of the insulating material to its pipe.
United States Patent 2,500,690, issued March 14, 1950
to G.~. Lannan, proposes apparatus for piling a mineral wool mat .
. up on itself by a corrugating or successive looping in opposite ~
directions of the mat, with the loops or corrugations extending .. .: -
.:: .
transversely of the path of advancement of the mat, and then ~ :
; curing the mat. The purpose of this prior apparatus was to
resist delamination or separation o:E the mat and to provide a .
~ . , .
- 20~ more rigid and board-like mat. However, with the more advance
mineral wool forming apparatuses presently in use, mats are ~:
formed which do not tend to delaminate. Moreover, rigid and :.
` board-like mats are completely unsuitable for pipe insulation,
since they cannot be bent to conform t~ the exterior surfaces of
pipes. ~ :
su~r or ~n~ nr-o~
:: .
- It is accordingly an object of the present invention
to provide a novel and improved apparatus for the manufacture of
insulating material which is particularly useful for the insula-
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tion of lar~e diame-ter pipes and which provides improved flexi-
bility to facilitate the manufacture, storage, transportation
and installation thereof, but which nevertheless retains suf-
ficient thermal resistance.
According to the present invention, there is provided
apparatus for manufacturing a heat insulating material from an
uncured, strip-shaped felt of fibres containing a heat harden-
able bonding substance, the apparatus comprising means for form-
ing in the uncured felt corrugations extending across the entire
width of the felt and following one another in succession along
the length of the felt; a felt curing section for applying heat
to the corrguated felt to form a cured felt containing fibres ex-
tending in a serpentine array along the felt between opposite
flat sides of the felt; means for longitudinally cutting the
cured felt to separate the cured felt into two partial felts;
and means for longitudinally conveying the felt along a path of
travel extending past the cutting means; the cutting means com-
prising a cutting blade extending transversely across the path
of travel, whereby the corrugations are severed so that the
fibres form U-shaped arrays disposed in succession alonq each
partial felt.
The formation of these U-shaped arrays of fibres has
the advantage that the insulating material formed by the partial
felts has a good compressive strength, which is provided by the
resistance to compression afforded by the arms of the U-shaped
arrays against forces acting in the longitudinal direction of
such arms, i.e. perpendicular to the major surfaces of -the par-
tial felts. These arms also are compressible transversely of
` the arms, which provide the partial felts with good flexibility.
; 30 In addition, the bridge portions of the U-shaped arrays, which
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extend generally parallel to those major surfaces, provide the
partial felts with good tensile strength and good thermal re-
sistance to the passage of heat in the direction extending per-
pendicular to the major su~faces.
BRIEF DESCRIPTION OF THE DRAWINGS
.
The invention will be more readily understood from the
following description of a preferred embodiment thereof given, ~ -
by way of example, with reference to the accompanying drawings,
in which:-
Figure 1 shows a diagrammatic side view of a production
line for manufacturing heat insulating material and embodying
the present invention;
Figure 2 shows a side view of a pleating apparatus
forming part of the production line of Figure l;
Figure 3 shows a view taken in transverse section ~
through a piece of heat insulating material formed by the pro- ~ -
duction line of Figure l; and
Figure 4 shows an end view of a pipe wrapped by heat
insulating material formed by the production line of Figure 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
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The production line illustrated in Figure 1 has a
plurality of endless belt conveyors 10A to 10G for longitudin-
: ally advancing a strip-shaped felt 11 from a conventional felt
forming hood indicated generally by reference numeral 12.
; The forming hood 12 incorporates two glass fibre
spinners 12A and 12B, and produces the felt 11 in the form of a
wool of glass fibres containing a heat hardenable bonding sub-
stance.
-, . . . . , - ,- , . . ~ . . ~ . , .- . . . .
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The felt 11, ln its uncured state, is fed from the
conveyor lOA, which is associated with the forming hood 12 and
over the conveyor lOB, which is downwardly inclined, to the
conveyor lOC which, together with conveyor lOD and two endless
belts 14A and 14B, form parts of a conventional felt pleater, : :
which is illustrated in greater detail in Figure 2. :.
: The conveyor lOD is vertically oscillatable, as will :~
be described in greater detail hereinafter, for formin~ corru-
gations 15 in the felt, and the endless belt 14B is downwardly :
inclined, in the direction of advance o~ the fel~ 11, and serves
to compress the corrugations lS.
From the conveyor lOD, the corrugated and uncured felt
passes into a curing section indicated generally by reference ~
numeral 17. ::
: The curing section 17 includes a hot air curing oven
18, which extends around the corveyor lOE and a corresponding
endless belt 18 disposed above the path of travel of the felt 11.
;~ Beyond the curing section 17, and above the endless
belt conveyor lOF, there is provided a cutting mechanism which
comprises a bandsaw 19 having a saw blade 19A.
The bandsaw blade l9A is arranged horizontally so that .:
it extends transversely across the path of travel of the felt
11 in a plane parallel to the major surfaces of the felt 11 and
across the entire width of the felt 11. Consequently, the band-
aw blade 19A bisects the felt 11 by severing the felt 11 into
two partial elts or mats llA and llB.
A pair of holcl-down rollers 20A ànd 20B are provided -
at opposite sides of the bandsaw 19 a~d extend transversely
across t~e width of the felt 11 above the conveyor lOF for en- ;
30 suring that the felt 11 is held in correct alignme~t with ~he :-~
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bandsaw blade l9A
Beyond the bandsaw 19, a pair of reels 22A and 22B are
provided above and below, respectively, the path of travel of the
felt for supplying backing strips 23A and 23B to the outer major
surfaces of the par-tial felt or mats llA and llB.~ pair of -
spray heads 24A and 24B are provided for spraying adhesive onto
the backing strips 23A and 23B before the latter reach the par- .
tial felts, the backing strip 23A being pressed against the upper
major surfaces of the partial felt llA by means of a roller 25,
10 and the backing strip 23B being pressed against the underneath
major surface of the partial felt llB ~y means of the conveyor
lOG.
From the conveyor lOG, the partial felts are fed past
a transverse cutting mechanism, indicated generally by reference
numeral 26, to a pair of guide rollers 27A and 27B. The trans-
verse cutting mechanism 26, which is of conventional construction,
incorporates a cutter blade 26A which is vertically reciprocable
for cutting the partial felts llA and llB transversely of their
widths to required lengths.
Directly before the transverse cutting mechanism 26,
a roller 29is provided for contacting t~e upper surface of the
upper partial felt llA. The purpose of this roller 29 is to
guide the partial felts and to prevent them from being raised by :.
the cutting mechanism 26 during its upward stroke. - :
At the rollers 27A and 27B, the partial felts llA and ::
llB are separated for guidance to two separate take-up roller
arrangements, indicated generally by reference numerals 28A and -
28B, by means of which the partial felts llA and llB are wound
into separate coils.
The felt pleater illustrated in Figure 2 f which is
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given as an example of one of a number o~ conventional felt
pleaters which could be employed in the practicing of the present
invention, has a machine frame indicated generally by reference
numeral 30, which supports a plurality of guide rollers 31a
through 31g for rotation about stationary axes, these rollers
31a through 31g serving to support and guide the endless con-
veyor belt lOC. :~
The conveyor belt 14A, which serves to hold down thefelt 11 on the upper run of the conveyor belt lOC, is guided
around four rollers 32a through 32e.
A further pair of guide rollers 33a and 33b guide a
vertical endless belt 34, which is disposed above the outlet ~-:
end of a gap formed between the belts lOC and 14A for the
passage of the felt 11.
Beyond the belt lOC, in the direction of advance of
the felt 11, the endless belt lOD is guided about a pair of
rollers 35a and 35b, which are rotatably mounted at opposite
ends of an oscillatory frame 36. ~ ~:
: The frame 36 is mounted for oscillation abowt the axis :
of a pivot shaft 37 extending transversely of the belt lOD, and
an electric drive motor 39 is connected by a drive chain 40 to
; a crank mechanism indicated generally by reference numeral 41 for
vertically reciprocating a vertical arm 42.
The upper end of the arm 42 is adjustably secured to a
vertical plate 43 by means of a manually engageable locking de~
vice 44 engaging in an arcuate slot 45 in the plane 43, and is .
adjustable along the slot 45 for varying the angle of oscillatlon
of the franle 36.
An electric drive motor 47 is connected by a chain and
sprocket drive transmission 48 and 49 to the roller 35b, which is
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,
rotatable about the sha~t 37 for driving the endless belt lOD,
. Since this pleater mechanism is o~ known and conven-
tional construction, it will not be described in greater detail
herein.
The operation of the above-described apparatus is as
follows.
As the felt 11 advances from the forming hood 12 to-
wards the pleater mechanism, and as a consequence of the normal
operation of the forming hood 12, the fibres of the felt 11
extend, in general, longitudinally thereof.
When the felt 11 passes over the conveyor belt lOC of
the pleater mechanism shown in Figure 2, it is held down onto -.
the upper run of the conveyor belt l~C by the hold-down conveyor
belt 14A, which is adjustable in height relative to the endless
: belt lOC. As the felt leaves the gap between the endless belts
. lOC and 14A, it passes onto the upper run of the endless belt, :
lOD. Meanwhile, the frame 36 is oscillated by the drive motor .
47 about the axis of the shaft 37, as indicated by arrow A in
Figure 2, the felt 11 being retained against the endless belt ;~
lOD by means of a hold-down plate 50, which is mounted for oscil- .
lation with the frame 36. : ~
The oscillation of the belt lOD displaces the felt up :.
and down relative to the vertical endless belt 34, against which
~ the corxugations are formed in the felt 11.
; As mentioned hereinbefore, the pleater mechanism is of
;~ ~ known and conventional construction, and is given herein simply
as an example o~ a number of known pleating mechanisms which may
~ be employed in the present inv.ention. The operation of this
; pleating mechanism will therefore be familiar to those skilled ;-.
in the art, and is not described herein in greater de~ail.
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As -the felt leaves the pleating mechanism, the fibres
generally have a serpentine array along the felt between the op-
pos.ite flat sides of the felt as a result of the formation of -the
corrugations 15.
The speed of the conveyor lOD, and o~ the following
conveyors lOE to lOG, are adjusted relative to the speeds of the
conveyors lOA to lOC such that the corrugations 15 are compres-
sed, .in the longitudinal direction of the felt 11, against one
another.
The endless belt 14B serves as a deflector for holding
down the corru~ations 15 by preventing the felt from springing
upwardly.
In the curing section 17, the conveyor lOE and the
uppex endless belt 18 are adjusted to a predetermined vertical
distance apart from one another in accordance with the required
thickness of the cured felt 11, and the felt 11 is cured in a
conventional manner as it passes th:rough the curing oven 18.
The bandsaw blade 19A may be adjusted to a position
midway between the major surfaces o:E the felt 11, so that the
20 partial felts llA and llB are produced with equal thicknesses, i`~
or may be offset towards one of the major surfaces of the felt
11 to provide partial felts of unequa~ thicknesses.
Although in the present embodiment of the invention,
as described above, the backing strips 23A and 23B are applied ~ ~ -
to the partial felts llA and llB beyond the bandsaw 19, it is ~
alternatively possible to apply backing strips to the major sur- -
.
~aces o the felt 11 prior to the arrival of the ~elt 11 at the
curing section 17. In this case, the backing is provided in the ;
form of a porous facing or reinforcement~ in order to allow the
hot gas to readily permeate and cure the felt 11, and it may not
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be necessary to apply adhesi~e to the backing strips before they
are applied to the felt ll.
Instead of coiling the partial felts llA and llB, as
described above, it is alternatively possible to operate the
cutter mechanism 25 in such a manner as to cut the partial felts
llA and llB into shorter lengths corresponding to the circum-
ferences of the pipes to which the heat insulating material is
to be applied, and these lengths can then be packaged flat for
storage and shipping.
lOAlso, whereas the above-described embodiment of the
invention has been described as including the felt forming
section 12, it should be understood that the latter does not
form an essential part o~ the present invention, since the pre-
sent invention can be performed on apparatus removed from the ~--
fibre forming section. For example, a roll cf uncured wool
could be stored and if required, transported, after its manu-
facture ln a forming section, and t~en fed into the pleating
mechanism, cured and cut, as described hereinabove, at a point
and time remote from its manufacture in the forming section.
Conse~uently, when employing a forming section of large capacity,
and provided for example with eight or ten spinners, the uncured
wool need not necessarily be fed directly to the pleating mech-
anism, which has a limited throughput capacity.
Figure 3 shows a view of part of the partial felt llA,
and more particularly shows, in end view, three adjacent insula-
ting material sections each formed by one-half of one of the
corrugations formed in the pleating apparatus bf Figure 2. ~ ;
These sections are of elongate shape, with their lengths extend-
,
ing perpendicular to the plane of Figure 3, and are bonded to-
gether in side-by-side relation by the bonding substance cured
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in the curing section 17.
Each of these sections comprises a generally U-shaped
array of fibres, which is shown diagrammatically in Figure 3,
the fibres at and adjacent one major surface 55 of the finished
heat insulating material extending generally perpendicular to
the major surface 55.
The opposite major surface of the material is bonded
to the backing sheet 23A, and the fibres at and adjacent this
opposite major surface are bent, as shown, to extend generally
10 transversely of their respective elongate material section. ;~
In Figure 3, the width of one of these material
sections is indicated by reference A, its height is indicated by -
reference B, and reference C indicates the distance from the
major surface 55 to the nearest point at which the flbres are
bent transversely of their respective section.
It will be readily apparent from the above description
of the method of manufacturing the material illustrated in
Figure 3, that each of these sections comprises a severed fold,
formed in the pleating apparatus of Figure 2, in the felt 11,
and that the width A of this fold or material section will be
determined by the initial thickness of the felt 11 and the amount
; of horizontal compression of the pleats formed by the pleating
apparatus.
The height B is determined by the thickness of the
initial felt 11 and the sizes of the pleats formed in the pleat-
ing mechanism, as also is the distance C.
The density of this product, which is controlled in
accordance with the degree of flexi~ility required in the
finished product, is controlled by determining the amount of
horizontal and vertical compression of the material fed into and
through the curing section 17.
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When the finished ~aterial is in use, the fibres ex-
tending perpendicular to the major surface 55 are compressible,
perpendicular to their length, to enable the ~inished material
to flex, e.g. when the material is coiled in a roll or wrapped
around a pipe. The fibres which are bent transversely of their
sections, at and adjacent the opposite side of the material, i.e.
the size bonded to the backing sheet, as described hereinabove,
provide resistance to heat flow through the insulating material.
Figure 4 diagrammatically illustrates the heat insula-
ting material of Figure 3 wrapped around a pipe 56. As can be
seen from Figure 4, the heat insulating material is disposed so
that the backing sheet 26~ is outermost, and wikh a part of the
cured felt cut away so that the backing sheet 26A provides a
flap 57 along one edge of the insulating material. The flap 57
- is overlapped onto and secured by adhesive to the opposite edge
of the backing sheet 26A, as shown, for securing together the
adjacent edges of the backing sheet 26A in order to retain the
heat insulating material in position around the pipe 56.
At and adjacent the exterior surface of the pipe 56,
20 the fibres extend substantially perpendicular to the pipe sur- -
; face and are compressed transversely of their lengths to enable
the heat insulating matexial to be flexed, as mentioned above,
and thus to be wrapped closely around the pipe 56. However, the
fibres at and adjacent the outer major surface of the material,
which is bonded to the backing sheet~ extend in the peripheral
direction, with respect to the pipe, and therefore provide a
greater resistance to heat flow radiall~ of the pipe than the
fibres extending perpendicularly with respect to the pipe peri-
phery.
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