Corrugated stainless steel tubing (CSST) was developed during 1980's in Japan and is today highly growing technology employed among others, in natural gas distribution and electricity wiring applications. Due to flexibility of the wall of such corrugated metal tube, the installation of the metal tubing formed of corrugated tubes is remarkably simpler and easier to carry out than installation of the respective tubing by using traditional metal tubes having straight walls requiring formation of bends in each such locations where the tube line has to change its direction. Among others, for this reason application of the CSST technology has substantially reduced installation time and thus labor costs in all those applications where it has replaced the traditional tubing technologies employing the tubes with a straight wall.

During the last decades plurality of fitting assemblies (or fittings) have been developed to ensure secure attachment and proper tightness in joints between corrugated tubes or hoses and the equipment to which the corrugated tubing is intended to be connected. A drawback of the presently known fittings is that, in some applications such as in installations of such apparatuses where a corrugated tube is led out from inside a container or casing being filled with pressurized medium (e.g. in heat exchangers and heat accumulators), the components of the known fittings typically remain inside the walls of the pressurized container and hence cannot be monitored by using visual inspection (e.g. in order to determine its condition or need for maintenance) or, in case of failure, repaired without dismantling the cover of such apparatuses. Furthermore, the presently known fitting assemblies for connecting the corrugated tubes with other equipment of installation typically include several components separate from each other such as nuts, sealing rings, washers, locking rings and locking pins and/or corresponding elements. Therefore, many fittings exist that are rather complex in construction and thus cumbersome to install and maintain, especially in such installations where the fitting has to be installed in to the inner side of a container or casing. Brief description of the invention

The aim of the invention is to provide a fitting assembly by means of which a corrugated tube that has been led out from inside an object (i.e. e.g. a casing or a container) can be realized in such a way that components of the fitting can be placed on the outer side of the object so that visual inspection, servicing and reconditioning of the fitting during its service life is possible without dismantling the cover of the object. The aim of the present invention is also to form a fitting assembly for corrugated tubing that is simpler in construction and has less separate components than the known fitting assemblies used for corrugated tubes led out from inside an object such as a casing or a container.

The aim of the present invention is achieved because in the fitting assembly according to invention, the part of the fitting assembly to which the corrugated tube is sealably attachable, is configured such that when the corrugated tube is attached in to this portion, the corrugated tube extends in the direction of the end of the fitting assembly that will be attached to the opening of the object to which the fitting has been attached. Therefore, when the corrugated tube is attached to a wall of the object, the fitting assembly is located on the outer side of the object if the corrugated tube extends from the opening in to the object. To put it more precisely, the fitting assembly according to invention is characterized what has been described in the independent claim 1 . The dependent claims 2-13 describe advantageous embodiments of the fitting assembly according to the invention.

The advantage of the fitting assembly according to present invention is that by means of it, the coupling of a corrugated tubing being led out from inside a casing or a container (typically having pressure that differs from ambient pressure) can be formed in such a way that the components used in the fitting assembly between the corrugated tube and the casing or the container can be realized such manner that all these components remain outside the outer walls of the casing or container and are able to be inspected by visual inspection and, when necessary, repaired or serviced within the lifetime of the apparatus in question. Furthermore, the further advantage of the invention is that installation of corrugated tubing becomes easier, simpler and less time consuming, especially in the case of installations with apparatuses where the corrugated tube is led out from inside a casing or container.

Description of the drawings

Next the invention is described in more detail by referring to the attached drawings wherein

figure 1 shows a cross section of a first embodiment of the fitting assembly according to the invention assembled to an object seen obliquely from above of the object,

figure 2 shows a perspective drawing of the first embodiment of the fitting assembly according to figure 1 ,

figure 3 shows a front view of the fitting assembly according to figures 1 and 2,

figure 4 shows a longitudinal cross-section of the fitting assembly of figures 1 to 3,

figure 5 shows a longitudinal cross-section of a second embodiment of the fitting assembly according to invention assembled to an object,

figure 6 shows a front view of the fitting assembly according to figure 5, figure 7 shows a perspective drawing of a third embodiment of the fitting assembly according to invention assembled to an object, and figure 8 shows a longitudinal cross-section of the fitting assembly according to figure 7. Detailed description of some advantageous embodiments

The embodiments of the fitting assembly according to invention shown in figures 1 to 4, 5 to 6 and 7 to 8 are fitting assemblies that are intended to be used for leading an corrugated tube through a wall of an object such as a container or casing, so that the corrugated tube extends out from inside the container or casing through its wall. Such situation takes place, for instance, with a heat exchanger or heat accumulator, where the heat is exchanged from or to a first heat exchange medium being inside the container or casing, or from or to a second heat exchange medium flowing in a corrugated tube arranged in to the container or casing. Typically, in such an apparatus the corrugated tube is arranged in spiral, zig zag or some other suitable form such that enough heat exchanging surface between the corrugated tube and the first heat exchanging medium is formed to exchange the desired amount of heat from the first heat exchanging medium to the second heat exchanging medium or vice versa.

The fitting assembly 10 shown in figure 1 comprises a first sleeve part 1 1 and a second sleeve part 12. The first sleeve part 1 1 is a portion of the fitting assembly 10 that is attachable to the edge of an opening 51 formed to an object 50 to which the fitting assembly is to be installed. This attachment can be accomplished fixedly by means of soldering or welding, or detachably e.g. by means of a nut and external threads formed on the outer surface of the first sleeve 1 1 part at its attachment end 13. However, in embodiments shown in figures 1 to 6, the object 50 to which the first sleeve 1 1 part is attached, is shown by means of square shaped piece of plate to which an opening 51 for the first sleeve part 1 1 has been formed. Herein generally described object 50 is typically a closed container or casing which should be gas and liquid tight i.e. that can have its inner side pressure being higher or lower than ambient pressure effecting outside the object 50. In both of the embodiments shown in the figures 1 to 4 and 5 to 6, the first sleeve part 1 1 has such type of an attachment end 13 that is configured to be fixedly attachable to the edge of an opening 51 formed to the wall of an object 50 to which the fitting assembly 10 is to be attached. The second sleeve part 12 is a portion of the fitting assembly 10 that can be fitted in to the first sleeve part

1 1 and to which the corrugated tube 40 can be sealably attached. The detachable connection between the first sleeve part 1 1 and the second sleeve part 12 has been configured such that when the second sleeve part

12 is to be fitted and secured in to the first sleeve part, gas or liquid inside the container cannot leak out from the container or casing 50 or in to the container from outside the container or casing through the connection. Also, because the corrugated tube 40 is connected in to the second sleeve part 12 through a coupling end 19 being in the side of the attachment end 13 of the first sleeve part 1 1 , all components of the fitting assembly leave outside the object 50 in case when the corrugated tube 40 extends out from inside the object 50. This is why the embodiments of the fitting assembly according invention shown in figures 1 to 4 and 5 to 6 are able to be inspected by visual inspection and, when necessary, repaired or serviced without disassembling the object 50 within the lifetime of the entity which both of these both elements are part of.

The first sleeve part 1 1 comprises an attachment end 13 and a receiving end 14. As described above, the attachment end 13 has been configured to be attachable to the opening formed to the object 50 to which the first sleeve part 1 1 is to be attached. As can be seen from figure 4 there is, in this case, formed near to the attachment end 13 of the first sleeve part 1 1 a narrowing at the edge such that a fixing corner 15 in to which the opening 51 having a bit smaller diameter than the outer diameter of the other portions of the first sleeve part 1 1 has been fitted so that the inner edge of the opening 51 becomes against the vertical edge of the fixing corner 15. This will make it easier to secure the first sleeve part 1 1 to the opening 51 accurately such that the first sleeve part 1 1 extends perpendicularly outside from the object 50. In this embodiment the attachment is accomplished by welding. However, in this kind of attachment soldering or brazing may be applied as well. Furthermore, other suitable attachment methods an means may be applied such as attachment with a ring nut screwed on the threads formed on the sleeve part 1 1 at the attachment end 13, so that the edge of the opening 51 can be compressed against the fixing corner 15 by means of the ring nut.

The receiving end 14 is the end through which the second sleeve part 12 is fitted in to the first sleeve part 1 1 . At the receiving end 14, the inner diameter of the first sleeve part 1 1 is larger than the inner diameter at the attachment end 13. The portion with enlarged inner diameter extends near the attachment end 13 where it terminates to a locking corner 16 after which the inner diameter of the first sleeve part 1 1 narrows to approximately the inner diameter that is equal or e.g. some tenths of millimeters larger than outer diameter of the corrugated tube 40 to be fitted in to the fitting assembly 10. The first sleeve part 1 1 further comprise locking apertures 17, through which a retaining pin 18 can be fitted for locking the second sleeve part 12 such that it cannot move out from inside the first sleeve part 1 1 . In this embodiment the retaining pin 18 is a U-shaped pin made of metal such as steel. However, retaining pins having other shapes and made of some other suitable material may also be used. For instance, one U-shaped pin may be replaced by one or more straight or L-shaped pins that can be fitted through the apertures 17, number of which can be two or more depending on the type and amount of retaining pins employed.

In the embodiment of figures 1 to 4, the retaining pin 18 is fitted through the apertures 17 after the second sleeve part 12 has been fitted in to the first sleeve part 1 1 in to its intended position. In that position, the parts of the retaining pin 18 being in the first sleeve part 1 1 remains at the outer side of a retaining corner 21 of the second sleeve part 12 and thus retains the second sleeve part 12 in the first sleeve part 1 1 as shown in the figures 1 , 2 and 4. Furthermore, in some other embodiments having this kind of retaining pin, the retaining corner 21 may be replaced with a suitable retaining groove that is formed on the outer surface of the second sleeve part 12 at the suitable position, such that the second sleeve part 12 is retained in the first sleeve part 1 1 similarly as in the embodiment shown in the figures 1 to 4.

The second sleeve part 12 comprises a coupling end 19 and an extension end 20. The coupling end 19 is an end that will be fitted in to the first sleeve part 1 1 through the receiving end 14 of the first sleeve part 1 1 when the second sleeve part 12 is assembled in to the first sleeve part 1 1 . In this embodiment, the inner and outer diameter of the second sleeve part 12 is at the coupling end 19 larger than inner and outer diameter at the extension end 20, i.e. there is a receiving portion 22 that extends from coupling end 19 to the direction of the extension end 20. The distance which the receiving portion 22 extends from the coupling end 19 to the direction of extension end 20 is less than the length of the portion of the first sleeve part 1 1 at the receiving end 14 having larger inner diameter than the inner diameter of the attachment end 13 of the first sleeve part 1 1 when the second sleeve part 12 is fitted in to its position in to the first sleeve part 1 1 . The receiving portion 22 terminates to a retaining corner 21 , after which the second sleeve part 12 extends as a terminal portion 23 having, in this embodiment, smaller inner and outer diameter than the inner and outer diameter of the receiving portion 22. The aim of this is to form a retaining corner 21 , by means of which the movement of the second sleeve part 12 out from the first sleeve part 1 1 (i.e. in the direction of its extension end 20) can be prevented as described above. For this reason, the retaining corner 21 is positioned such that it will be in the first sleeve part 1 1 when the second coupling end 19 of the sleeve part 12 is against the locking corner 16 in the first sleeve part 1 1 .

In this embodiment, the receiving portion 22 of the second sleeve part 12 comprises on its outer surface two retaining grooves 24. When the second sleeve part 12 has been fitted in to the first sleeve part 1 1 , two sealing rings 25 have been introduced between the receiving portion 22 and the inner surface of the first sleeve part 1 1 . The aim of the retaining grooves 24 is to retain the sealing rings 25 at the right position on the receiving portion 22 such that the sealing rings 25 provide sealing that prevents leaking of gas or liquid through the connection between the first sleeve part 1 1 and the second sleeve part 12. The number of retaining grooves 24 and sealing rings 25 can vary in different embodiments of the fitting assembly according to the invention. To ensure required tightness, there has to be at least one sealing ring 25 between the second sleeve part 12 and the first sleeve part 1 1 , but in such embodiments being designed for demanding applications, three or more sealing rings 25 and retaining grooves 24 may be introduced.

The receiving portion 22 of the second sleeve part 12 provides also a sealed connection for the corrugated tube 40. In this embodiment the corrugated tube 40 will be fitted in to the receiving portion 22 through its coupling end 19. Therefore, the inner diameter of the receiving portion 22 is approximately equal to the outer diameter of the corrugated tube 40. As can be understood and seen from figures 1 and 4, the shape of the outer surface of the corrugated tube 40 provides as such retaining grooves for one or more sealing rings 26. In this embodiment, two sealing rings 26 have been introduced between the corrugated tube 40 and the receiving portion 22 in to which the incoming end 41 of the corrugated tube 40 has been fitted. Also herein minimum number of sealing rings 26 would be one but alternatively three or more sealing rings 26 may be used in such embodiments where extremely reliable sealing is needed. In order to secure the corrugated tube 40 in to the receiving portion 22 of the second sleeve part 12, a locking ring 27 has been introduced between the outer surface of the corrugated tube 40 and the locking corner 16 of the first sleeve part 1 1 . For preventing the corrugated tube 40 from moving in both of its lengthwise directions, the corrugated tube 40 has been positioned in respect to receiving portion 22 such that it remains (when the second sleeve part 12 is in its connected position in respect to the first sleeve part 1 1 ) between the locking corner 16 of the first sleeve part 1 1 and the coupling end

19 of the second sleeve part 12. Hence, in this embodiment, the locking corner 16 prevents the incoming end 41 of the corrugated tube 40 from moving in the direction of the object 50 and the coupling end 19 prevents it from moving too far inside the receiving portion 22. As can be seen from figure 4, there is some clearance between the incoming end 41 of the corrugated tube 40 and the inner edge of the terminal portion 23 of the second sleeve part 12. This is to enable adjusting the position of the incoming end 41 of the corrugated tube 40 in the receiving portion 22 such that the locking ring 27 can be assembled in suitable position in respect to the outer surface of the corrugated tube 40 (i.e. such that a narrower point of the outer surface of the corrugated tube 40 can be positioned to the point where it locates between the coupling end 19 of the second sleeve part 12 and the locking corner 16 of the first sleeve part 1 1 ).

At the extension end 20 of the second sleeve part 12, the terminal portion 23 may have some suitable connecting means to connect the extension end 20 of the second sleeve part 12 with some external tube or other equipment, typically belonging to the system or arrangement which portion the object 50 forms. Thus, for providing this, the terminal portion 23 at the extension end

20 may, for instance, comprise outer or inner threads, be weldable, solderable or bondable, or have standard dimensions so that universal tube connectors can be applied for connecting the terminal portion 23 with an external tube or other equipment to which the tubing led from inside the object 50 is intended to be connected.

When installing the fitting assembly 10 according to figures 1 to 4, the corrugated tube is fitted through the first sleeve part 1 1 out from its receiving end. In the next phase, the sealing rings 26 are assembled on the first two depressions (i.e. narrower portions of the corrugated tube 40) at outer surface of the corrugated tube 40 when counted from the incoming end 41 of the corrugated tube 40 as can be seen from figures 1 and 4. After that, the incoming end 41 of the corrugated tube it is fitted in to the receiving portion 22 such that the third depression sets at the point where it is just in the front of the coupling end 19 of the second sleeve part 12, such that when the locking ring 27 is installed against the coupling end 19 in the following phase, its inner edge is fitted in to the third depression. After installation of the locking ring 27, the sealing rings 25 are installed on the second sleeve part 12 to the point of the retaining grooves 24, after which the second sleeve part 12 is fitted in to the first sleeve part 1 1 to the position shown in figures 1 and 4. Alternatively, the sealing rings 25 can be installed earlier, for instance, before installation of the corrugated tube 40 in to the second sleeve part 12. Finally, the retaining pin 18 is fitted through the locking apertures 17 of the first sleeve part 1 1 such that the it remains behind the edge of the retaining corner 21 on the side of extension end 20. Thus, the retaining pin 18 prevents the second sleeve part 12 from moving out from the first sleeve part 1 1 through its receiving end 14. After installation of all components of the fitting assembly 10, the corrugated tube 40 extends inside the object 50 from the fitting assembly 10 through the opening 51 such that entire fitting assembly 10 remains outside the object 50. Thus, in case when the corrugated tube 40 is led out from inside the object 50 through the aperture 51 , the fitting assembly 10 does not have any components inside the object 50 and hence the fitting assembly 10 reaches the object of the invention as described above. Furthermore, it can be understood, from the above descriptions, that the disassembly of the fitting assembly 10 according to figures 1 to 4 can be carried out by performing the corresponding disassembling operations in the opposite order as the assembling operations described above.

Figures 5 and 6 show a second embodiment of the fitting assembly according to invention. This embodiment is similar to embodiment shown in figures 1 to 4 except that the attachment of the second sleeve part 12 in to the first sleeve part 1 1 has been realized in different manner. In the embodiment shown in figures 5 and 6, the retaining pin 18 is replaced with an inner threaded portion 28 formed in the inner surface of the first sleeve part 1 1 , an outer threaded portion 29 on the receiving portion 22 of the second sleeve part 12, and a nut member 30 formed between the extension end 20 and the outer threaded portion 29 of the second sleeve part 12. The outer threaded portion 29 having an outer diameter larger than the receiving portion 22, has been arranged to engage with inner threaded portion 28 when the second sleeve part 12 is fitted in to the first sleeve part 1 1 . Thus, when the second sleeve part 12 is installed in the first sleeve portion 1 1 , the second sleeve part 12 is screwed in to the first sleeve part 1 1 such that the coupling end 19 of the second sleeve part 12 abuts against the locking ring 27. The edge of the nut member 30 being at the side of receiving portion 22 then abuts against the receiving end 14 of the first sleeve part 1 1 such that a suitable clearance for locking ring 27 remains between the coupling end 19 of the second sleeve part 12 and the locking corner 16 of the first sleeve part 1 1 . In this embodiment the nut member 30 is a standard type of hexagon nut which can be screwed by means of standard tools such as adjustable, fork or socket wrench.

Figures 7 and 8 show a third embodiment of the fitting assembly according to invention. The embodiment of the fitting assembly according to figures 7 and 8 differs from embodiment of figures 1 to 4 as well as embodiment of figures 5 to 6 in that the receiving portion 22 of the second sleeve part 12 comprises a fitting section 31 that is fitted in to the corrugated tube 40. In this case, the fitting section 31 has been arranged to extend from the connection point of the first sleeve part 1 1 and the second sleeve part 12 a suitable distance in to the corrugated tube 40. Due to this difference the both sealing rings used for ensuring tightness between the corrugated tube 40 and the fitting assembly have been placed on the outer and the inner side of the corrugated tube 40. This will simplify the construction, since any retaining grooves need not to be formed either to the first sleeve part 1 1 or the second sleeve part 12.

Furthermore, the embodiment of the fitting assembly according to figures 7 and 8 differs from the embodiments of figures 1 to 4 and 5 to 6 in a way that the first sleeve part 1 1 and the second sleeve part 12 are to be attached to each other. The attachment consists of, in this case, one fixing flange 32 at the receiving end 14 of the first sleeve part 1 1 and an another fixing flange 33 in between the receiving portion 22 and terminal portion 23 of the second sleeve part 12, by means of which the first sleeve part 1 1 and the second sleeve part 12 are held together. In order to secure the fixing flanges 32 and 33 against each other in way shown in the figures 7 and 8, a special binding element 34 is provided. The binding element 34 is a kind of a locking spring that has a base portion 35 and two arc-like branches 36 and 37. The shape of the branches 36 and 37 conforms with the outer surface of the first sleeve part 1 1 and the second sleeve part 12 in the vicinity of the fixing flanges 32 and 33. The branch 36 is fitted on one side and the branch 37 on the other side of the first sleeve part 1 1 and second sleeve part 12 abutting against each other. Both branches 36 and 37 include slots 38, through which the abutting fixing flanges 32 ja 33 are to be fitted when the binding element 34 is assembled on to its place where it retains the first sleeve part 1 1 and the second sleeve part 12 against each other in the above mentioned manner. Thus, the width of the slots 38 have been designed so that the fixing flanges 32 and 33 can be fitted through the slots 38 only when they are pressed against each other as shown in figure 7. The binding element 34 is preferably made of some enough stiff sheet-like material such as metal, plastic or composite.

The fitting assembly according to invention can be further realized in many ways being different from the above described embodiments. For instance, in such embodiments of the fitting assembly being kind shown in figures 1 to 4 or 5 to 6, the fitting assembly may be realized such that sealing between the corrugated tube and the fitting assembly would be arranged between the outer surface of the corrugated tube and the inner surface of the first sleeve part. In that case, the narrower portion extending from the attachment end of the first sleeve part would be longer than in the embodiments shown in the figures 1 to 4 and 5 to 6. However, the locking ring may be attached between the coupling end of the second sleeve part and the locking corner of the first sleeve part but then the sealing rings between the incoming end being fitted in to the receiving portion of the second sleeve part would not be necessary, although in some embodiments also these could be employed. Also the attachment of the second sleeve part in to the first sleeve part may be accomplished by means of securing means being different from the ones described above. The second sleeve part may be secured to the first sleeve part e.g. by means of separate fixing screws fitted through a fixing holes made to a fixing flange formed to the second sleeve part e.g. to the same position as the nut element is in the embodiment of figures 5 and 6. In such embodiment, the fixing screws may be screwed in to a threaded holes extending from the receiving end of the first sleeve part in to the direction of the attachment end. Furthermore, the material of the fitting assembly may vary in different embodiments of the fitting assembly according to the invention. It is preferably made from some metal such as stainless steel, aluminum, brass or copper. However, also non-metallic materials such as plastic or composite materials may be used. Either the corrugated tubes with which the fitting assembly can be used should not be limited only to corrugated tubes made of some metallic materials such as stainless steel or aluminum. The fitting assembly may be applied for connecting of corrugated tubes made of, for instance, plastic or many kinds of composite materials as well. Therefore, the fitting assembly according to invention should not be limited to the embodiments described above but can be varied within the scope of the appended claims.