A METHOD AND A DEVICE FOR ATTACHING INSULATION MATERIAL ON THE OUTSIDE OF PIPELINES

Abstract: In an attachment method and an attachment means for attaching insulation mats (12, 12') each laid surroundingly around a longitudinal portion of a pipeline (10), jointing spaces are formed between individual mats (12, 12'). A long-term durable, tensioned, locked connection at each joint space is desired. Preferably, divided, bendable, semi-rigid attachment bands of metal, exhibiting tensile strength are used. These are placed individually in the area of each joint space and tightened around neighbouring end portions of adjacent insulation mats (12, 12') while the attachment band (18a, 18b) is centred laterally in that an internal bead engages guidingly into the joint space (16). One end portion (18b') of one attachment band half (18b) may be fastened to the adjacent end portion (18a') by means of screws (22), while the other end portions (18a' and 18b') are provided with holes (24') and plastically deformable lips (24) to be passed therethrough, respectively, the efficient length of the attachment band halves (18a and 18b) and the positioning of the lips (24) and of the holes being such that the threading of the lips (24) through the holes and their subsequent bending causes a tightening of the attachment band (18a, 18b). The lip material acts as a locking means for the tightening and retaining action of the attachment band (18a, 18b) to the insulation mats (12, 12').

Description: A METHOD AND A DEVICE FOR ATTACHING INSULATION MATERIAL ON THE OUTSIDE OF PIPELINES The present invention relates to a method and an attachment device for attaching insulation material which, preferably in the form of insulation units such as mats, is placed insulat- ingly around the outside of pipelines which e.g. may be of the kind included in ventilation plants. Conventional fastening of such insulation mats which each, preferably, extends one turn around the pipeline, has con- sisted in taping adjacent end portions of the insulation mats in pairs, so that tape covers the insulation mat joints. Empirically, it has be found that such tape loosens after some time, resulting in the formation of apertures in the pipeline insulation, causing a deterioration of the insulat- ing properties, simultaneously as particles of the insulation material gradually will be released therefrom and pollute the underlying room. Known technique dealing with various solutions associated with fastening and fixing insulation units/material, does not solve the above defined problem. Prior art as represented through patent publications, are elucidated in the following: GB patent specification No. 1,134,432 deals with an insulation layer attached directly to the inner face of a jacket surrounding e.g. a knee. Metal rings are used only in order to achieve a better appearance between one casing and another . GB patent application No. 2,255,818 deals with an insulated pipeline, in which the entire insulation layer is encapsu- lated within a metal jacket. Some places on this insulated and encapsulated pipeline, have been made available upon the removal of annular metal jackets with insulation and inserted therein divided, semi-circular, insulated insert pieces which may easily be removed and brought into place again by means of easily releasable, mutually co-operating locking means at adjacent ends. Normally, the insulation layer around the inner pipe is very well protected within the fully covering metal jacket. This has no similarity to insulated pipelines in which the insulation is fully unprotected, only kept to- gether at the joint areas by means of tape. DE 29 10 983, deals with a removable insulation compensator accommodating various expansions in insulation material and pipeline due to temperature increases (the drawings are defective and the specification lacks an explanation of the general structure of the pipeline) . However, it seems as if the insulation of the pipeline is encapsulated within a jacket, and that an annular insert is divided and insertable/ withdrawable. The problems sought to be solved according to the invention, recovered where insulation mats were rolled around a pipeline, fixed thereto at the joint places by means of tape, do not exist here. DE 36 34 347, deals with a device for thermal insulation of the seams between adjacent vacuum heat insulation elements which, at one side, bear against a gas-tight, pressure proof wall. The insulation material is encapsulated between covering sheet plates. It is these plates that are jointed by means of sheet lists crossing each other right-angledly, the insulation material proper seemingly extending intactly between the plates. GB patent specification No. 1,593,255 deals with a method for covering insulated/metal coated joints between cylindrical sections. This external clothing/ insulation is covered by panels encapsulating the clothing and overlapping each other. Here, overlapping end edge portions of the panels can be fixed directly to each other without exhibiting a large force accommodating/transferring ability. Instead, around each overlapping place for the panels (which are not insulation mats, but has the task of covering a probably adhering insulation layer on the outside of the tubular or similar sections) , stretchable, lockable bands have been disposed. In accordance with the present invention, around adjacent end portions of neighbouring insulation mats or insulation mate- rial in some other form, i.e. within the joint areas formed between each pair of insulation units, disposed bendable, lockable bands, especially metal bands in the form of flexible bands of sheet metal. Thereupon, the respective attachment band is tensioned evenly around adjacent insulation end portions at each joint space in the insulation, the tension- ing also being able to cause a simultaneous locking of the respective attachment band in tensioned condition, or that the attachment bands may be subjected to a locking operation subsequently to the tensioning. By means of such attachment bands which may be made relatively narrow in relation to the individual length extent of the insulation mats, the aforesaid defined problem relating to freely supported insulation units surrounding pipelines without any other connection with the pipeline than at the joint spaces of the insulation units, is solved in a simple manner. Such bendable, tensionable, lockable attachment/ fastening bands may, without great costs, be manufactured, mounted and tightened such that they also are secured against loosening for a long time. Any deterioration of the insulation of the pipeline due to the formation of unintentional apertures between the insulation units due to the lack of holding means will, therefore, not arise. If possibilities exist for threading in the attaching bands from one pipeline end, the attachment bands may have closed annular shape and be equipped with an appropriate tensioning device. Usually, such a threading possibility does not exist, and the attachment band is, therefore, usually made in form of a bendable band or, possibly, in the form of a divided band. Then, a tensioning device may consist of plastically deformable lips/tongues at the one free end and insertion holes in the other free end portion. The lip is inserted into and through the insertion hole and bended over such that an appropriate tensioning in the attachment band is achieved, simultaneously as locking is established through the plastic deformability of the tongues. If desired, the attachment band may be provided with a plurality of spaced insertion holes, so that the same attachment band can be used for varying pipe diameter/ insulation thickness. In order to secure an advantageous centring of each attachment band in the area of the joint spaces of the insulation mats, the attachment band or each attachment band half, respectively, may be formed with a central, inwardly projecting bead orientating itself such in said space that the attach- ment band easily centralises laterally. Such a bead may be 360° continuous or formed by means of several bead portions or the like, spaced at mutually equal distances. This centring or positional fixing, continuous bead may, possibly, be deleted if the band, at that side which come rest against the opposing insulation face, is provided with projections in the form of spikes. Such spikes are particularly efficient when used with insulation kept in place by means of an external net having small meshes, the spikes engaging positionally fixingly into the meshes of the net. Advantageously, the spikes may be formed through punching triangular attachment band material configurations in the form of slop- ingly projecting, pointed spike-like portions of the attachment band. A non-restricting exemplary embodiment of an attachment band in accordance with the invention is further explained in the following, reference is made to the drawings, in which: Figure 1 shows a fragmentary longitudinal view through the wall of an externally insulated pipeline, the insulation mats thereof at the respective joint space being firmly connected to the pipeline by means of an attachment band; Figure 2 shows a lateral section through pipeline, insulation and a divided attachment band according to the invention; Figure 3 shows a divided attachment band fastened to a pipeline; Figure 4 corresponds to figure 3, but here the attachment band is shown from the opposite side, where one free band end carries two projecting, plastically defor able lips passed through holes in the other free band end as well as bent lockingly over, so that the tongues extend almost parallel to the band face in the locking position; Figure 5 corresponds to figure 4, but illustrates an embodiment-comprising punched out spikes as well as a centring circular bead; Figure 6 shows a plurality of attachment bands fixed around a band where the central portion is shown in axial section; Figure 7 shows a laterally angled attachment band to be placed at the joint place for a branch pipe; Figure 8 shows a cross-section along the line VIII -VIII in figure 7. First, reference is made to the embodiment shown in figures 1 - 4. Identical components, parts and portions are indicated by the same reference numerals in figures 5 - 8. Reference numeral 10 denotes a pipeline intended to be included in e.g. a ventilation plant or a pipe plant for water. Externally, the pipe line 10 is provided with insulation units 12 and 12', e.g. in the form of insulation mats which, at least externally in relation to the pipeline 10, may have a foil layer 14, 14', in order to keep the insulation material proper better together. Especially in pipelines for water, it may also be used shape-durable insulation where two opposing insulation halves surround the pipe. Joint spaces between adjacent insulation mats 12, 12' are denoted at 16. It appears from figure 1 that an attachment band 18 according to the invention has been laid around adjacent end portions of neighbouring insulation mats, and that the end portions, thus, are clamped somewhat together in the radial direction of the pipeline 10; this being due to the tensioning of the attachment band 18. Likewise, figure 1 shows an inwardly directed bead-shaped centring projection 20 which, upon the mounting and tightening of the attachment band 18 will seek to orientate itself within the space 16 of jointing between two neighbouring in- sulation end portions and, thus, centre the attachment band laterally. This bead-shaped centring projection 20 may consist of a circu ferentially extending, continuous bead or of bead portions disposed in mutually equal distances or similar projecting means. Figure 2 which is a cross-sectional view along the section plan line II - II in figure 1, shows an attachment band design consisting of two approximately 180° semi-circular attachment band parts 18a, 18b, both having the same width and the same central bead design 20. The two attachment band halves 18a, 18b overlap each other at both adjacent end portions and are, at one overlapped end area, interconnected by means of screws 22, which exclusively have a connecting function; also see figure 3. At the other overlapped end area, plastically deformable lips 24 on a radially seen innermost end portion 18b' of the attachment band half 18b have been passed through through-going holes 24' in the radially seen outermost end portion 18a 1 of the attachment band half 18a. The longitudinal proportion is such that when the major part of the plastically deformable lips 24 on the attachment band half 18b have been pulled through said through-going holes in the attachment band half 18a, the joined attachment band halves 18a, 18b will be appropriately tightened around a standard insulation mat laid around a pipeline 10 having a given diameter, so that when the lips 24 are folded down about 90° from the piercing position an adequate tensioning is established in the attachment band 18; 18a, 18b. An absolutely necessary measure for establishing attachment band assemblies without any tendency of loosening, displacement or other weakening of the retaining function thereof, is the locking of the tightened attachment band 18; 18a, 18b. When using said bendable lips 24, stretching and locking are simultaneously provided for. When the lips and the adjacent portions of the end portion of the attaching band half are dimensioned adequately, the ability to deform plastically will provide a locking effect which does not let itself be nullified. Also, the attachment band will be capable of being tightened and, thereupon, locked by means of a screw connection or in another known way. Figures 5 - 8 show an embodiment characterised in band ate- rial punchings in the form of triangular spikes 26 projecting slopingly out from the attachment band face opposing the outer insulation side face. Each of these spikes 26 may have a narrow triangular circumferential shape tapering toward the free end and being connected to the remaining attachment band body at the opposite, broad end, and where each of the triangular spikes 26 normally will form a right angle with adjacent attachment band face facing the outer face of the insulation. Sometimes in association with insulation around pipes, an ex- ternal net (not shown) having small meshes and adapted to retain the insulation is used. Spikes 26 on the inner side of the attachment band are especially advantageous in connection with such fixing nets, as the spikes 26 will engage positional-fixingly into the small net meshes, so that the centring means 20, possibly, may be deleted. Attachment bands 18 having spikes 26 may also be used on the previously described insulation 12, 12' which, outermost, is provided with a foil layer 14, 14 ' . In figure 6, an attachment band according to the invention is used to retain the insulation in position around a bend zone. The composite bend may be formed on the basis of an adequately large radius of curvature or, as indicated in figure 6, through successive angulations. The cross-section of each attachment band 18, see the attachment band extending around the joint 16A, has side faces parallel to the angled portion of the insulation 12, 12' surrounded by the band 18. In figures 7 and 8, a specially shaped attachment band has been shown, adapted to provide secure hold on of insulation around a branch pipe IOC emanating perpendicularly from a pipeline 10D. At its central portion, this special attachment band 18 has a right- angled cross-section, the band ends be- ing twisted and made flat downwardly toward opposite fastening points 28, simultaneously as the attachment band portions all the time rest supportingly and retainingly against the external insulation face (mesh net face) around branch pipe IOC and pipeline 10D in the jointing area.

Claims: P a t e n t k r a v 1. A method for attaching insulation material, preferably in the form of insulation units (12, 12'), on the outside of a pipeline (10), the insulation units each (12, 12') being brought to extend substantially 360° around a longitudinal portion of the pipeline (10) , leaving an intermediate joint (16), the insulation units (12, 12') at each joint (16) being attached to the pipeline (10) through fastening means, c h a r a c t e r i z e d i n that said fastening means in the form of a bendable, semi-rigid attachment band (18; 18a, 18b) exhibiting tensile strength, preferably of metal, is placed around adjacent end portions of respective insulation units/insulation bodies (12, 12') and positionally fixed e.g. in relation to the intermediate joint (16) , tightened and locked. 2. An attachment means for use when carrying out the method as defined in claim 1, c h a r a c t e r i z e d i n that said attachment means consists of a bendable, semi-rigid attachment band (18; 18a, 18b) exhibiting tensile strength, preferably of metal and which, in an annular active position, is adapted to be tightened around neighbouring 360° annular end portions of adjacent insulation units/insulation bodies (12, 12') juxtaposed in the longitudinal direction of the pipeline, r and that the attachment band (18; 18a, 18b) is as- signed a tension means (24) and a locking means for securing it in the tensioned condition thereof, or a combined tension/locking means (24), and that the attachment band (18; 18a, 18b) has fixing means (20; 26; 20, 26) co-operating with the two adjacent insulation units/ insulation bodies (12, 12') and/or net surrounding the insulation, in order to positionally fix the attachment band (18; 18a, 18b) laterally. 3. An attachment means as defined in claim 2, c h a r a c te r i z e d i n that the attachment band (18; 18a, 18b), centrally in the longitudinal direction, has a bead-like design (20) constituting said centring member and which may be 360° coherent or broken in the longitudinal/circumferential direction of the attachment band (18; 18a, 18b). 4. An attachment means as defined in claim 2 or 3, c h a r a c t e r i z e d i n that the attachment band is divided and has at least two free end portions (18a', 18b') having overlap possibility in the position of use, and that one (18b') of the free end portions has projection-like piercing and securing means (24) , and the other free end portion (18a') has a through-going hole (24') for the piercing and subsequent bending of said piercing and securing means (24) . 5. An attachment means as defined in claim 4, c h a ^ r a c - t e r i z e d i n that said piercing and securing means consists of at least one plastically deformable lip (24) , the length and positioning thereof in relation to the hole (24') of the other attachment band portion being such that a folding of the lip (24) subsequently to its piercing in the hole (24*) provide a tightening and locking of the attachment band (18; 18a, 18b). 6. An attachment means as defined in claim 2, wherein the insulation (12, 12') preferably is surrounded by a net having small meshes, c h a r a c t e r i z e d i n that the side face of the attachment band (18) which in use faces the insu- lation (12, 12'), exhibits projections in the form of spikes (26). 7. An attachment means as defined in claim 6, c h a r a c t e r i z e d i n that the spikes (26) are formed by attachment band material punchings in the form of preferably triangular spikes. 8. An attachment means as defined in any one of the preceding claims, wherein insulation units (12, 12') are placed around a bend, c h a r a c t e r i z e d i n that the attachment band (18) , divided or continuous, has a cross section paral- lei to the adjacent insulation (12, 12'). 9. An attachment means in the form of a special attachment band for use in the jointing area at a branch pipe (IOC) emanating from a pipeline (10D) , the special attachment band exhibiting an annular shape in the position of use, c h a r- a c t e r i z e d i n that the special attachment band (18,20,18) at two first points positioned diametrically opposed, the imaginary connecting line thereof imaginarily dividing the branch pipe in the middle of its cross section, has a substantially 90° angled cross section, and that the special attachment band from these diametrically opposed points has been twisted and made flat toward the fastening point (28) of the band halves.

Inventors: LEA TOR REIDAR, LEA, TOR, REIDAR
Applicants: LEA TOR REIDAR, LEA, TOR, REIDAR
Application year: 1998
Main classification: F16L50
IPC codes: F16L59