FASTENING ARRANGEMENT AND A METHOD FOR SECURING TUBES ARRANGED WITHIN EACH OTHER

Abstract: The invention relates to a fastening arrangement for sequentially interconnecting tube portions (1) comprising nested tubes (2, 3). The joint comprises a conical portion (5) for receiving an external locking band (6). Said conical portion (5) comprises a portion of insulating material extending inwards beyond an outer tube (3) into an insulating space between said tubes (2, 3). Separate supporting means (15, 16, 19) for said insulating material are associated with said conical portion (5). The invention further relates to a method for securing the stability of nested tubes (2, 3) in connection with a tube system comprising modular tube pieces (1) each of which comprises an inner tube (2), an outer tube (3) as well as at least partially conical end pieces located at the ends of said tubes and comprising, as such, an insulating portion. A separate supporting ring (19) is arranged at the insulating portion of said end pieces and said outer tube (3) is attached using a fastener (18) extending to behind a plane constituted by an extension of said supporting ring (19).

Description: Fastening arrangement and a method for securing tubes arranged within each other The invention relates to a fastening arrangement for sequen¬ tially securing respective tube portions, said portions com¬ prising tubes arranged within each other, using conical joints arranged at the end of said tubes, each of said conical joints comprising a conical portion made of a resilient but rather stiff insulating material for receiving a locking band. The invention also relates to a method for securing the stability of nested tubes in a tube system, said system comprising sequentially interconnectable modular pieces, each of which comprise an inner tube, an outer tube, as well as, at the ends of said tubes, at least partially conical end pieces com¬ prising an insulating seal. Such fastening arrangements are known from joint arrangements for so-called modular tubes, as an example of which Finnish Patent No. 92098 may be mentioned. Said patent discloses nested tubes between which an insulation is arranged, a gene¬ rally conical flange ring coacting with a separate tightening band. For simple modular tubes an arrangement according to Finnish Patent No. 92246 may be used. In both cases generally conical end pieces i.e. flange rings are pressed against each other and locked using a separate locking band having the general shape of a double cone. In both cases a conical ring portion is made of metal or the like material and arranged at the outer surface of the tube entity. Thus, said conical ring will be located at the outside of any insulation in said double tube arrangement comprising an inner and an outer tube. The present invention relates to an improved fastening arrange¬ ment and especially to such a one where an insulating material as such is used as the material for said conical flange ring, to which a sealing and suitably resilient portion at least partially will connect. Favorably, for the conical insulating portion such an insulating material will be used, which as such is sealing and relatively stiff but still resilient, for example silicone, neoprene rubber, special plastics or the like material, which withstands the heat applied in the tube and which does not form, upon heating, toxic or otherwise harmful gases. For double tubes a conical ring made of such materials replaces the insulation between the inner and outer tubes and favorably simultaneously acts as a seal between said tube portions. A certain resilience simultaneously facilitates the control of small angular variations and a secure locking and sealing. However, said resilience also provides a drawback related to the materials or combinations of materials used since it causes a situation where the dimensional stability as such might not be sufficient. A secure attachment of the inner and outer tubes to the conical portion may also constitute a problem, due to the slightly diffuse shape of said portion. According to the present invention this problem is solved in accordance with the appended claims. Thus, the invention is characterized in that an, as such, insulating and rather stiff material portion of said conical portion extends inwards beyond said outer tube into an insulating space located bet¬ ween said tubes, suitably between said inner and said outer tubes or corresponding portions thereof, said conical portion comprising separate supporting means for the insulating material of said conical portion and favorably a separate formation arranged for receiving said outer tube. The inven¬ tive method is characterized in attaching said outer tube in such a manner that at least one separate supporting ring is arranged at the generally stiff insu ϊting portion of said end pieces and in securing said outer tube to said insulating portion using a fastener which extends behind the plane defined by the extension of said supporting ring for said insulating portion. The invention will now be described in more detail with refe¬ rence to the appended exemplifying drawings, wherein a favorable embodiment of the invention is disclosed. In the drawings Figures 1, 2 and 3 generally disclose partial sections of arrangements according to some of the simplest embodi¬ ments of the invention in such a manner that said Figures disclose two joined ends of modular tubes, respectively, Figure 4 partially in section discloses an especially prefer¬ red embodiment of the invention, and Figure 5 in section discloses the arrangement according to Figure 4 adapted to a separate series of extension pieces for the interconnecting of tubes. According to Figure 1, a modular tube 1, la in a tube system generally comprises an inner tube 2, 2a, an outer tube 3, 3a arranged coaxially with respect to said inner tube, as well as generally an insulation layer 4, 4a arranged in an insulating space between said tubes. As a rule, said tube system must be constituted in such a manner that sequential inner tubes 2, 2a extend essentially unbroken. Media, which are hot or cold with respect to the ambient temperature, may flow in said tubes, and the purpose of said insulation 4, 4a is to prevent heat from passing from said inner tube outwards or vice versa. Thus, it will be appreciated that also said insulation 4, 4a would extend unbroken with respect to its properties. On the other hand, the functional idea in modular tubing is that a rather extensive tube system can be relatively easily as¬ sembled from parts having standard dimensions, where the range of parts besides the straight tubes disclosed herein may com¬ prise curved portions and different adaptor and branch ele¬ ments. Of course, what herein is expressed in context with modular tubes can also be applied in context with such further parts . CT/FI97/00228 Figure 1 discloses conically shaped interacting joint pieces, i.e. conical portions 5 and 5a. At the connecting said conical portions 5, 5a will be located end-to-end and pressed against each other by a locking ring or band 6 having the general shape of a double cone, in such a manner that conical surfaces of said band will press against conical surfaces 7, 7a at said joint pieces, thus forcing said tubes 1, la together and keeping them there. In the Figures the joint structure of said tubes 1, la is disclosed in a slightly caricatured manner in order to more clearly show interacting sealing surfaces 8, 8a of said coni¬ cal portions 5, 5a, which surfaces will be located against each other. According to the invention each conical portion 5, 5a is made of a favorably slightly resilient and compressible but at the same time insulating material, where especially sealing portions 9, 9a in practice will be compressed to such an extent that the ends 10, 10a of said tubes 2, 2a usually will be located practically against each other. According to the invention each conical portion 5, 5a will extend, contrary to prior art, essentially unbroken from the general annular plane of said outer tubes 3, 3a into the in¬ sulating space between said tubes 3, 3a and 2, 2a, where said conical portion 5, 5a in the embodiment disclosed in the drawings in practice will completely substitute said in¬ sulation 4,4a in the joint region. In Figure 3 there is dis¬ closed an arrangement where a proper insulation 4, 4a is further arranged in the space between said conical portion 5, 5a and the inner tube. As material for said conical portion 5, 5a suitably silicone, neoprene or the like insulating material is used, which mate¬ rial simultaneously will slightly flex and thus as such act as an effective seal. Since said materials generally as one pro ¬ perty show a certain resilience or in some cases alternatively a certain brittleness said materials are simultaneously to some extent exposed also to other deformations. Thus, the inventive solution also comprises the feature of supporting said conical portion's insulating material using a separate support. In the arrangement according to Figure 1 a relatively hard sealing insulating material is used, especially a suitable special plastics, and then a short flange-like por¬ tion 11, lla will be sufficient, which in the disclosed embodi¬ ment is formed directly by shaping the end of said inner tube 2, 2a. Here it should be observed that the actual sealing force will originate explicitly due to the interaction between the coni¬ cal inner surface of said locking band 6 and the conical sur¬ faces 7, 7a of said conical portions 5, 5a made of insulating material, where said inner and outer tubes 2, 2a, 3, 3a mainly will only follow. Since the continuity of the inner tube 2, 2a usually is considered to be important, the end of said inner tube is appropriately formed in such a way that the clamping force via said insulating material will act also directly at said inner tube 2, 2a. For said outer tube 3, 3a the actual clamping force usually is of less significance but instead it is important that said outer tube 3, 3a and therewith said insulation 4 will remain essentially in place. For this reason said conical portion 5, 5a made of insulating material is appropriately equipped with a separate counter formation 25 at said outer tube 3, 3a, which formation to its shape will attach to the end of said outer tube. Figure 2 discloses an arrangement corresponding to the one disclosed in Figure 1. Here each supporting portion is formed by a backwards directed portion 12, 12a which may be an un¬ broken flange or may be constituted by separate wings which are located mutually spaced apart. Figure 2 also discloses a sealing surface arrangement where a sealing edge extends beyond the end of each modular tube 1, la at least prior to the connecting, said sealing edge further comprising, in the embodiment disclosed in Figure 2, a hollow portion 13. As such C /O 228 it will be evident that the sealing edge ' 8, 8a also may com¬ prise other formations like different kinds of lip structures or the like. In structures according to Figures 1 and 2 said conical portion 5, 5a can be assembled e.g. by bending said sealing insulating material ring over said flange-like supports 11, lla, and 12, 12a. The outer surface of said conical portion 5, 5a is shaped as a formation 25 supporting said outer tube 3, 3a, and since a resilient accommodating portion of insulating material i.e. said conical portion 5, 5a extends over the whole insulating space, both tubes will be kept in position within the resilience of said conical portion 5, 5a. In the structure according to Figure 3 the inner diameter of said conical portion 5, 5a is clearly larger than the outer diameter of said inner tube 2, 2a. Thus, a separate insulating layer 14, 14a can be arranged between said conical portion 5, 5a and said inner tube 2, 2a. In the embodiment shown, the conical portion 5, 5a itself is made of a relatively hard essentially unbendable insulating material, to which a sepa¬ rate sealing portion 9, 9a is attached, which e.g. by gluing is attached to the actual insulating conical portion 5, 5a. In order to secure a sufficient supporting for said conical portion under all conditions, said support is in this embodi¬ ment made as a flange 15, 15a, the outermost portion 16, 16a of which favorably supports, suitably from behind or at the center, the portion of insulating material 9, 9a attached to said conical portion 5, 5a. Obviously it will be difficult to arrange such a conical portion in place between already shaped inner and outer tubes and further so that an extra insulation 14, 14a will be located in a desired manner. For this reason said structure comprises a separate sleeve-like inner tube portion 17, 17a at which said conical portion 5, 5a and any possible extra insulation 14, 14a is arranged favorably prior to the connecting procedure. In order to keep the assembly together said outer tube 3, 3a and said conical portion are favorably interlocked, in this case, by a separate fastener 18, suitably by a self-boring special screw, rivet or the like. In another embodiment said attachment is arranged between said inner tube 2, 2a and said sleeve-like inner tube portion 17, 17a, respectively. Figure 4 discloses an especially favorable embodiment which is developed from the general arrangement disclosed in Figure 3. In this embodiment the alignment and stability between said outer tube 3, said inner tube 2 and said conical portion 5 is secured by a separate supporting ring 19 which is located at the end of said conical portion, i.e. said ring made of a sealing and insulating material, in an annular groove 20 ar¬ ranged at the inner rim of said ring. An inner edge 21 of said supporting ring, on the other hand, is supported against said inner tube 2 and especially against said sleeve-like inner tube portion 17. By locating a fixing means 18, e.g. a fastening screw, in such a way that it will be located, seen in the direction of the outer tube 3, behind said supporting ring 19 or its imagined extension, i.e. within the supporting ring's range of influence, said fixing means 18 will in prac¬ tice take support from said supporting ring even when the conical portion's 5 resilient portion of sealing and in¬ sulating material is located between said fixing means 18 and said supporting ring. Figure 4 further discloses that in¬ sulating material in certain cases can be saved by the use of hollow portions or filler pieces 22. Figure 5 discloses a separate interconnecting piece which is realized in accordance with the arrangement according to Figure 4, said piece comprising, respectively, a sleeve-like portion 17 to be located in said inner tube 2 and, corres¬ pondingly, a separate sleeve-like portion 23 to be located in said outer tube, said sleeve-like portion comprising a lip seal 24. Such elements may especially well be used as joint and adapting elements as mentioned above. Above some favorable embodiment of the invention have been described as examples, but for the person skilled in the art it is evident that the invention can be altered in many other ways within the scope of the appended claims.

Claims: Claims 1. A fastening arrangement, respectively, for sequentially interconnecting tube portions (1, la) comprising nested tubes (2, 2a, 3, 3a) via conical joints (5, 5a, 6) located at the end of said tubes, each individual conical joint comprising a conical portion (5, 5a) adapted for receiving a locking band (6) , c h a r a c t e r i z e d in that said conical portion (5, 5a) comprises a portion of insulating material extending inwards beyond an outer tube (3, 3a) into an insulating space between said tubes (2, 2a, 3, 3a), separate supporting means (11, lla, 12, 12a, 15, 15a, 16, 16a, 19) for said insulating material being associated with said conical portion (5, 5a) . 2. An arrangement as defined in claim 1, c h a r a c t e ¬ r i z e d in that said supporting means (11, lla, 12, 12a, 15, 15a, 16, 16a, 19) are made of a material which differs from the insulating material of said conical portion (5, 5a) and is stiffer than said insulating material, said material suitably being metal. 3. An arrangement as defined in claim 1 or 2, c h a r a c ¬ t e r i z e d in that said support (15, 16) extends from the level of an inner tube (2) outwards at least to the level of said outer tube (3) , suitably approximately to the center of said conical portion (5, 5a) . 4. An arrangement as defined in any one of claims 1 to 3, c h a r a c t e r i z e d in that at least one supporting means (11, lla, 12, 12a, 15, 15a, 16, 16a, 19) is functionally associated with an inner tube (2, 17) suitably so that a sup¬ porting means (19) extends essentially to said inner tube (2, 17, 17a) and/or so that said supporting means (11, lla, 12, 12a, 15, 15a, 16, 16a, 19) constitutes a part of said inner tube (2, 17, 17a), suitably a flange (11, lla, 15, 15a) , a fold (12, 12a) or the like portion thereof. 5. An arrangement as defined in any one of claims 1 to 4 , c h a r a c t e r i z e d in that a separate formation (25) is arranged for the reception of said outer tube (3, 3 a) and that a separate fastener (18) is arranged for attaching said outer tube (3, 3a) to said conical portion (5, 5a) within the range of influence of said supporting means (19) for said insulating material. 6. An arrangement as defined in any one of claims 1 to 5, c h a r a c t e r i z e d in that at least one supporting means comprises a separate supporting ring (19) which suitably is arranged in a groove (20) in said insulating material. 7. An arrangement as defined in any one of claims 1 to 6, c h a r a c t e r i z e d in that said insulating conical portion (5, 5a) as such is of a relatively hard material, to which a separate sealing portion (9, 9a) of a more resilient material is associated, said sealing portion preferably being supported by a supporting means (16, 16a). 8. A method for securing the stability of nested tubes (2, 2a, 3, 3a) in connection with a tube system comprising sequen¬ tially connectable modular pieces (1, la) which, respectively, comprise an inner tube (2, 2a), an outer tube (3, 3a) as well as at least partially conical end pieces located at the ends of said tubes and comprising, as such, an insulating portion, c h a r a c t e r i z e d in arranging at the generally stiff insulating portion (5, 5a) of said end pieces at least one separate supporting ring (19) and attaching said outer tube (3, 3a) using at least one attaching means (18) which extends to behind a plane constituted by an extension of said sup¬ porting ring (19) for said insulating portion (5, 5a) . 9. A method as defined in claim 8, c h a r a c t e r i z e d in using said supporting ring (19) for aligning said in¬ sulating portion (5, 5a) of said end piece with respect to an inner tube (2, 2a) and/or for keeping a separate insulation (14) in a space between said insulating portion (5, 5a) of said end piece and said inner tube (2, 2a) . 10. A method as defined in claim 8 or 9, c h a r a c t e ¬ r i z e d in using a screw, rivet or the like essentially oblong piece as said attaching means (18) , said piece being brought to penetrate the wall of said outer tube (3, 3a) and to sink into said stiff insulating material (5, 5a) .

Inventors: HAUTALA REIJO, HAUTALA, REIJO
Applicants: HAUTALA REIJO, JYVASKYLAN IVK TUOTE OY, HAUTALA, REIJO, JYVASKYLAN IVK-TUOTE OY
Application year: 1997
Main classification: F16L59
IPC codes: F16L59