METALLIC PIPE ELEMENT FOR A FLUE

Abstract: A pipe element (10) for a flue is disclosed, which comprises a metallic circular pipe body having a first predetermined diameter; said element is further provided, close to a first and thereof, with an area (11) having a diameter which is slightly larger than said first diameter. The edge of the metallic pipe end having a larger diameter is internally folded, and it is provided with a series of radial cuts (12) which allow said end to be folded. Furthermore each portion which is comprised between two radial cuts in on one hand folded in such a way as to be parallel to the pipe longitudinal axis, on the other hand folded in such a way as to perpendicular to said axis. In this way a metallic locking nut is formed inside of the pipe, in the larger diameter area. The other pipe is provided, by means of a mould, with a series of ribs (15) which are adjacent to each other and which form a thread suitable for cooperating with said locking nut in order to join together a pair of adjacent pipes. The joining operation is carried out in a very simple way, by inserting one end of a pipe into the conjugated end of an adjacent pipe and by carrying out a rotation about the pipe axis until the respective locking nut and thread elements reach an abutment position.

Description: METALLIC PIPE ELEMENT FOR A FLUE. ******** TECHNICAL FIELD The present invention relates to a metallic pipe element for a flue. More particularly, the present invention relates to a metallic pipe element for flue which may easily be coupled to another conjugated pipe element, and which warrants a very good junction seal between said pipe elements. The invention may be mainly applied in the field of prefabricated building. BACKGROUND ART Several different flues are known, which are formed by a plurality of superposed elements coupled by a mutual insertion of their ends, a connection strip being normally provided in the connection area between two adjacent elements in order to keep a good mechanical seal and to prevent the outlet of smoke from the connection area. The flue pipe elements which are normally used involve a plurality of disadvantages and drawbacks, which are mainly due to undeniable difficulties for assemblying the flue. In fact, the pipe elements known in the art have the same diameter at both ends, and this causes a big trouble during the insertion of a pipe end into the end portion of another identical element. Furthermore, said elements are kept together by means of a metallic strip which, since the contact surfaces of both pipe elements are completely smooth, needs to have a remarkable width, in order to have a suitable contact surface with the interconnected pipe elements. Finally, the seal doesn't result to be very good from the mechanical point of view and taking into consideration a possible outlet of smoke from the connecting area between the various pipe elements. DESCRIPTION OF THE INVENTION The present invention aims to obviate the disadvantages and drawbacks which are typical of the background art, and to provide, thus, for a pipe element for a flue, which may be coupled to another similar element in an extremely quick way by an operator, and which simultaneously guarantees a perfect coupling of the pipe elements joined by their respective ends. This is achieved by means of a pipe element for flue having the features disclosed in the main claim. The dependent claims outline advantageous forms of embodiment of the invention. The pipe element for a flue according to the invention comprises a metallic circular pipe boby having a first predetermined diameter; according to a feature of the invention, said element is further provided, close to a first and thereof, with an area having a diameter which is slightly larger than said first diameter. This conformation obviously allows a pair of pipe elements to be easily joined together, since the diameter of the pipe boby is smaller than the diameter of the end area of the adjacent pipe. According to the invention, the edge of the metallic pipe end having a larger diameter is internally folded, and it is provided with a series of radial cuts which allow said end to be folded. Furthermore each portion which is comprises between two radial cuts is on one hand folded in such a way as to be parallel to the pipe longitudinal axis, on the other hand folded in such a way as to perpendicular to said axis. In this way a metallic locking nut is formed inside of the pipe, in the larger diameter area. The other pipe is provided, by means of a mould, with a series of ribs which are adjacent to each other and which form a thread suitable for cooperating with said locking nut in order to join together a pair of adjacent pipes. The joining operation is carried out in a very simple way, by inserting one end of a pipe into the conjugated end of an adjacent pipe and by carrying out a rotation about the pipe axis until the respective locking nut and thread elements reach an abutment position. According to the invention, a sealing gasket is previously inserted into the larger diameter pipe area, close to the locking nut. Said gasket, in operation, warrants a total seal against any possible outlet of smoke. In this way the purposes of the invention are achieved, since both a merely mechanical seal of the joint, and a seal against a possible outlet of smoke are assured. ILLUSTRATION OF DRAWINGS Other features and advantages of the invention will become apparent by reading the following description of a form of embodiment of the invention, given as a non-limiting example, with the help of the figures illustrated in the attached drawings, in which: - fig.l is a schematical side view of a pipe for flue according to the invention; - fig. 2 is a schematical perspective view of the pipe of fig.l; - fig. 3 is a schematical perspective view of the joint of a pair of adjacent pipes according to the invention. DESCRIPTION OF A FORM OF EMBODIMENT In the figures, reference sign 10 generally indicates a metallic pipe for flue according to the invention. Pipe 10, which may have any diameter, according to the requirements, comprises a first end 11 having an area whose diameter is slightly larger than the diameter of pipe 10. As it may be noted in fig.2, in correspondence of said first end the edge 11 of pipe 10 is folded towards the inner part of the pipe. The edge is folded by carrying out on the edge a series of cuts 12 and, thereafter, by folding inwardly the tabs 13 comprised between two adjacent cuts 12. Furthermore, concerning each tab 13, a portion of the latter is completely folded against the inner wall of pipe 10, while another portion is only partially folded and it is substantially perpendicular to the inner wall of pipe 10. The series of tabs 13, which are folded in this way, forms a locking nut for a second adjacent pipe having some features which will be later described in detail. Pipe 10 has a second end 14, close to which is formed, by means of a suitable mould, a series of ribs 15, forming a thread suitable for cooperating with the locking nut as described above. The flue element according to the invention is completed by a sealing gasket 16 made of a heat resistant resilient material, which is placed closed to the locking nut, within the enlarged diameter pipe portion. Referring to fig.3, it may be noted that the operation for joining togheter two adjacent flue elements is very simple. In fact, in order to carry out this operation it will suffice to insert an end 14 of a pipe 10 into the conjugated end 11 having a larger diameter of an adjacent pipe 10', and to successively rotate a pipe (or both, in opposed directions in respect to each other) . Ribs 15 of pipe 10 are inserted into the locking nut of pipe 10' and, according to the number of ribs and tabs which respectively define the thread and the locking nut, a perfect joint of both pipes is obtained by a rotation of a fraction of revolution, e.g. by a rotation of one sixth revolution, i.e. a rotation of 60°. During this operation the sealing gasket is held between the external wall of pipe 10 and the inner wall of the enlarged diameter area of pipe 10 ' , and it carries out its functions against a possible outcome of smoke from the joint area. The invention has previously been described with reference to an advantageous form of embodiment of the same. However it is clear that the invention includes several variants which fall within its scope. By way of example, the invention englobes some forms of embodiment according to which the cupling between two adjacent flue elements is obtained by means of a joint connection, in which a pipe end is provided with one or more protruding elements which are inserted jointed inside of suitably shaped cavities which are present in the conjugated end of an adjacent pipe. This and other variants are possible within the scope of mechanical equivalences.

Claims: CLAIMS 1. Metallic pipe element (10) for flue, comprising a substantially cylindrical pipe body having a predetermined diameter, characterized in that one of the ends of said element (10) is formed by a portion (11) having a diameter larger than said predetermined diameter, in that said portion (11) is provided with first means (13) for rotatably coupling said end to the other end (14) of another metallic pipe element (10'), and in that said other end (14) is provided with second coupling means (15) suitable for cooperating, in operation, with said first means (13) . 2. Element according to claim 1, characterized in that said first joining means are costituted by a locking nut formed inside of said portion (11) having a larger diameter. 3. Element (10) according to claim 2, characterized in that said locking nut is obtained by folding inwardly the edge of said portion (11) , in said fold is subdivided into a plurality of tabs (13) separated from each other by cuts (12) , and in that each tab has a first part which is perpendicular to the inner wall of element (10) and a second part which is parallel to said inner wall. 4. Element (10) according to claim 2, characterized in that said second means are constituted by a series of inclined ribs (15) forming a thread suitable for cooperating with said thread. 5. Element (10) according to anyone of claims 2 to 4, characterized in that it comprises a sealing gasket made of heat-resistant material and which is placed in said portion (11) having a larger diameter. 6. Element according to claim 1, characterized in that a pipe end is provided with one or more protruding elements which are inserted into suitably shaped cavities which are present in the conjugated end of an adjacent pipe.

Inventors: ZAMBONI ELIO, ZAMBONI, ELIO
Applicants: MENIFLEX S R L, MENIFLEX S.R.L.
Application year: 1996
Main classification: F16L27
IPC codes: F16L27, F16L37, F23J13