Universal indissoluble pipe connection system and joint comprised in said system

Abstract

A universal pipe connection system includes a fitting with a tubular body and an annular bulge defining an annular groove on the inner side of a tubular body, which houses a sealing gasket. The tubular body receives the end portion of a pipe so that a pressing tool having opposite pressing jaws can engage the tubular body and generate a circumferential band adjacent to the bulge by mechanically clamping the tubular body in the circumferential and axial directions and causing a deformation of the annular bulge, which presses the gasket, and generates a seal between the tubular body and the end of the pipe inserted therein. The annular bulge and the corresponding annular groove have a geometry and size adapted to cooperate with two different types of pressing tools, one with a M profile and one with a V profile, which may be present in the alternative or in combination.

Claims

1. A universal pipe connection system comprising: a fitting comprising a tubular body (1) with an annular bulge (101) at least at an end portion, the annular bulge forming on, an inner side of the tubular body, an annular groove (201) housing a sealing gasket (2), the annular groove being open towards an inside of the tubular body, the end portion extending on a side opposite to an end of the fitting with a cylindrical portion (401), wherein said tubular body (1) provides a fitting socket for an end portion of a pipe (4); and at least one pressing tool (3) having at least two opposite pressing jaws, which are configured to cooperate with said end portion (101, 301, 401) of the fitting, by surrounding the end portion of the fitting along its circumference, the pressing jaws having a profile of a surface in contact with said end portion of the fitting shaped to press said end portion of the fitting against the end portion of the pipe (4) inserted into said fitting, causing, in at least one circumferential band adjacent to the annular bulge, a contemporaneous deformation of a wall of the pipe (4) and of at least of one cylindrical portion (301, 401) of said end portion (101, 301, 401) of the fitting, so that the end portion of the fitting and the wall of the pipe become mechanically clamped together in a circumferential and axial direction and a deformation of the annular bulge (101) presses the gasket (2), generating a sealing effect between said tubular body (1) and the end of the pipe (4) inserted therein, wherein: the annular bulge (101) and the annular groove (201) are provided at a given axial distance from the fitting, there being provided an initial cylindrical portion (401) between said end of the fitting and a side of the bulge facing said end of the fitting; the annular bulge (101) and the groove (201) have such a geometry and size to cooperate alternatively with two different types of pressing tools selected among a pressing tool (3) having a M profile and a pressing tool (3) having a V profile; and the universal pipe connection system comprises, alternatively or in combination, both the pressing tool (3) with jaws having a profile corresponding to the M profile of the fitting and a pressing tool with jaws having a profile corresponding to the V profile of the fitting.

2. The universal pipe connection system according to claim 1, wherein one or both of the annular bulge or the annular groove housing the scaling gasket have side walls composing two facing radial sides of said annular bulge and of said groove (101, 201), the side walls being inclined in a converging direction, symmetrical or asymmetrical with respect to each other, in a direction opposite to a center of the tubular body.

3. The universal pipe connection system according to claim 2, wherein the side walls or the radial sides of said annular bulge and of said annular groove form therebetween an angle ranging from 50° to 70°.

4. The universal pipe connection system according to claim 1, wherein the sealing gasket (2) has a non-rounded cross-section.

5. The universal pipe connection system according to claim 4, wherein the sealing gasket (2) has a cross-section widening towards a open side of the annular groove (201) in a manner corresponding to a sectional shape of said annular groove having rounded sides.

6. The universal pipe connection system according to claim 4, wherein the sealing gasket has a cross-section shaped as an isosceles trapezoid with convex bases.

7. The universal pipe connection system according to claim 4, wherein the sealing gasket has a cross-section essentially shaped as a geometrical figure enclosed between two segments of equal sides of an isosceles triangle with a vertex angle ranging from 55° to 65°, a first arc of circumference of radius r inscribed in said isosceles triangle, and an arc of radius 2r centered in a middle point of said first arc.

8. The universal pipe connection system according to claim 7, wherein said isosceles triangle is an equilateral triangle.

9. The universal pipe connection system according to claim 1, wherein the scaling gasket has an inner diameter equal to or smaller than an inner diameter of the tubular body.

10. The universal pipe connection system according to claim 1, wherein the tubular body comprises: at least two sides joined by a curved connection portion, the annular bulge and the annular groove each having two side walls and the cylindrical portion connected thereto with a curved flare, the annular bulge having a radial projection with respect to a diameter of an outer side of the cylindrical portion, wherein: the two sides wall are connected with each other by a curved portion having a radius ranging from 1 to 2.5 mm; said radius has a size ranging from 3 to 7% of a diameter of the tubular body; said two side walls form two sides of the bulge and of the annular groove and are connected to the cylindrical portion by the curved flare having an equal radius of curvature as said two side walls and ranging from 0.25 to 0.75 mm; the radial projection of the annular bulge changes for outer diameters of the cylindrical portion of the fitting from 18 mm to 60 mm, and from 2 to 4 mm; the radial projection of the annular bulge in relation to a diameter of the outer side of cylindrical portions on the two sides thereof ranges from 5% to 15% of the diameter of the outer side of said cylindrical portions; an axial distance between a central axis of the annular bulge and a free edge of the cylindrical portion at a port of the fitting ranges from 10 to 16 am for diameters of the cylindrical portion ranging from 20 to 60 mm; the axial distance is higher than 20% of an outer diameter of the cylindrical portions; and a thickness of a wall of the fitting is essentially the same for an entire axial length thereof and is about 3 mm.

11. A pipe press fitting for connecting pipes indissolubly and in a water-tight manner, comprising: a tubular body (1) with an annular bulge (101) at least at an end portion, the annular bulge forming, on an inner side of the tubular body, an annular groove (201) housing a sealing gasket (2), the annular groove being open towards an inside of the tubular body, the end portion extending on a side opposite to an end of the fitting with a cylindrical portion (401), wherein said tubular body (1) forms a fitting socket for an end portion of a pipe (4), wherein the pipe press fitting has a profile in an axial section compatible, for pressing, alternatively both with a tool for pressing M profile fittings and with a tool for pressing V profile fittings.

12. The pipe press fitting according to claim 11, wherein the pipe press fitting is includes in a system comprising: the tubular body (1) with the annular bulge (101) at least at the end portion, the annular bulge forming on, the inner side of the tubular body, the annular groove (201) housing the sealing gasket (2), the annular groove being open towards the inside of the tubular body, the end portion extending on a side opposite to an end of the fitting with a cylindrical portion (401), wherein said tubular body (1) provides the fitting socket for the end portion of the pipe (4); and at least one pressing tool (3) having at least two opposite pressing laws, which are configured to cooperate with said end portion (101, 301, 401) of the fitting, by surrounding the end portion of the fitting along its circumference, the pressing jaws having a profile of a surface in contact with said end portion of the fitting shaped to press said end portion of the fitting against the end portion of the pipe (4) inserted into said fitting, causing, in at least one circumferential band adjacent to the annular bulge, a contemporaneous deformation of a wall of the pipe (4) and of at least of one cylindrical portion (301, 401) of said end portion (101, 301, 401) of the fitting, so that the end portion of the fitting and the wall of the pipe become mechanically clamped together in a circumferential and axial direction and a deformation of the annular bulge (101) presses the gasket (2), generating a sealing effect between said tubular body (1) and the end of the pipe (4) inserted therein, wherein: the annular bulge (101) and the annular groove (201) are provided at a given axial distance from the end of the fitting, there being provided an initial cylindrical portion (401) between said end of the fitting and a side of the bulge facing said end of the fitting; the annular bulge (101) and the groove (201) have such a geometry and size to cooperate alternatively with two different types of pressing tools selected among a pressing tool (3) having a M profile and a pressing tool (3) having a V profile; and the system comprises, alternatively or in combination, both the pressing tool (3) with jaws having a profile corresponding to the M profile of the fitting and a pressing tool with jaws having a profile corresponding to the V profile of the fitting.

13. The pipe press fitting according to claim 11, wherein one or both of the annular bulge or the annular groove housing the sealing gasket have side walls composing two facing radial sides of said annular bulge and of said groove (101, 201), the side walls being inclined in a converging direction, symmetrical or asymmetrical with respect to each other, in a direction opposite to a center of the tubular body.

Description

[0052] These and other characteristics and advantages of the present invention will be more clear from the following description of some embodiments shown in the annexed drawings wherein:

[0053] FIG. 1 is a section according to an axial central plane of the fitting according to the present invention associated with a pressing tool whose jaws are shaped such to exert a pressing action on fittings with M profile.

[0054] FIG. 2 is a view similar to FIG. 1 wherein the fitting according to the present invention is associated to a pressing tool whose jaws are shaped such to exert a pressing action on fittings with V profile.

[0055] FIG. 3 is an axial section view of the fitting showing typical dimension configurations thereof for different diameters of the pipe.

[0056] FIG. 4 is an enlarged cross-section view of the gasket according to a preferred embodiment of the invention.

[0057] With reference to figures they show the fitting only as regards an end tightly connecting to a pipe. Such end can be provided firmly coupled to a device such as a inlet/outlet union of a valve, a cock, a filter, a meter or the like or said end is provided on connection ports of joints such as for example elements joining two pipes, union tees, L-shaped fittings, multiway fittings, on at least one of the connection ports or on all the connection ports, the remaining connection ports being provided with other types of fittings such as threaded fittings or with locking rings, or the like, it being obvious for a person skilled in the art to use said fitting as an end of any union for connecting pipes.

[0058] As it results from FIGS. 1 to 2, a fitting for a pressfitting system according to the present invention has a tubular body 1, made of metal material, such as for example stainless steel (inox), carbon steel, copper and copper alloys, which has, on an end portion and at a predetermined distance from said free end, an annular bulge 101, seen in longitudinal section of the tubular body 1, protruding from the outer perimeter of the latter. Such annular bulge 101 on the inner side of the tubular body 101 forms a correspondingly shaped annular groove 201 which is opened towards the inside of the tubular body 1 and which is intended to house an annular gasket 2. Said free end is the end for the insertion of an end portion of a pipe or union 4 to be firmly connected both mechanically and tightly to the tubular body 1.

[0059] The annular bulge 101 therefore is interposed between two cylindrical portions 301, 401 of the tubular body 1 of which an end portion 301 and a portion 401 connecting to the remaining part of the joint that, as mentioned above, can be a union for the connection to a device or one or more further connection ends of one-way or multiway joint.

[0060] At the other end of the tubular body 1, the cylindrical portion 401 is provided internally with an annular abutment shoulder 5 for example a radial inner annular rib and/or a radial sinking that is at a given distance from the annular bulge 101 and that is the stop abutment for the insertion of the end portion of the pipe or union 4.

[0061] In alternative embodiments such shoulder 5 can also be omitted.

[0062] The bulge 101 has, in the non-pressed condition of press fitting P, still seen in the longitudinal section of tubular body 1, the section of an isosceles triangle. In the present embodiment, such as shown in FIG. 3, the vertex angle, that is the angle at the top of the isosceles triangle, is about 60°.

[0063] According to a further preferred characteristic and such as shown in a non-limitative manner in the figure, also the base angles comprised between both sides or flanks of the bulge 101 can be about 60° with respect to the longitudinal axis L of the tubular body 1.

[0064] By means of that, the bulge 101 has, in section, the shape of an equilateral triangle, as a special form of isosceles triangle.

[0065] On the inner side of the tubular body 1, the bulge 101 coincides with an annular groove 201 wherein the gasket 2 is housed, preferably made of elastic, deformable material, for example an O-ring.

[0066] Said gasket can have an inner diameter that, in the non-pressed condition of bulge 101 and without the pipe 4, is at least about 1.5%, preferably about 1.5% to 2.5%, shorter than the inner diameter of cylindrical portions 301, 401. The gasket 2 is therefore arranged between the two side walls of the annular groove 201 defining an angle of 60° therebetween or such that the gasket cannot move during the insertion of the pipe 4 in the cylindrical body up to the shoulder 5.

[0067] The cylindrical portions 301 and 401 of the tubular body 1 form a socket for the insertion of the end portion of a pipe or union 4 and have an inner diameter slightly larger than the outer diameter of the pipe 4, while the inner diameter of the gasket 2, in the condition inserted on the fitting, is equal or slightly shorter than the outer diameter of said pipe 4 intended to be inserted in the tubular body 1 of the fitting.

[0068] According to a further advantageous improvement, resulting from FIGS. 1 and 2 and 4, the gasket 2 has a cross-section with a particular shape. The cross-section thereof has substantially the shape of an isosceles trapezoid with convex bases or sides.

[0069] Such shape is different from the conventional circular shape of O-rings in that with reference to the radial direction with respect to the axis of the tubular body 1, the gasket widens towards the side thereof facing the axis of the tubular body and it tapers towards the opposite side that is the shorter base of the trapezoidal shape.

[0070] According to one embodiment, the shape of the cross-section of the gasket 2 can be obtained from an isosceles triangle by cutting out the angles with two opposite arcs of circle, one of which has a radius that is twice the other, such as shown in FIG. 4.

[0071] Thus the gasket 2 has a cross-section of increased area with respect to a traditional O-ring gasket that can be inserted in the same housing 201. Consequently, also the compression factor of the gasket and its tightness after compression both by tools intended to press M profiles and tools intended to press V profiles operating on the same hybrid profile of the fitting according to the present invention are perfect and also possibly higher than those that can be obtained by conventional gaskets with circular cross-section.

[0072] According to a preferred embodiment of the invention, shown in FIG. 4, the cross-section of the gasket 2 has the shape of a geometrical figure enclosed between segments AB and DE of the two sides of an isosceles triangle with a vertex angle ranging from 55° to 65°, an arc AE of a circumference having radius r, inscribed in said isosceles triangle, and an arc BD having radius 2r centered on the middle point O of the arc AE, where A and E are the tangent points on triangle sides of the inscribed circumference, and B and D are the intersection points with the arc of radius 2r. Preferably, said isosceles triangle has a vertex angle of 60° and it is therefore an equilateral triangle.

[0073] By means of its cross-section shape, the gasket 2 fills almost completely the cavity of the housing groove 201. The area of its section is about 20% larger than that of a gasket having a circular cross-section which could have been inserted into the same housing 3 and this leads to a compression factor about 15% higher than that of a conventional gasket having a circular cross-section. Therefore the tightness of the pressfitting equipped with the gasket according to this embodiment is guaranteed both whether the compression deformation of the bulge 101 and therefore of the gasket 2 occurs by using pressing jaws with a profile corresponding to the M profile and by using pressing jaws with a profile corresponding to the V profile of the fitting. In the first case, with the use of jaws for M profile, the deformation of the bulge 101 and of the gasket 2 causes, after pressing, the bulge and gasket to take a cross-section with a substantially trapezoidal shape, in the second case, with the use of jaws for V profile, generally the shape of the bulge and gasket after pressing tends to be a substantially triangular shape.

[0074] With reference to FIGS. 1 and 2 they show the profile of the fitting in combination with a jaw for M profile and V profile respectively.

[0075] In both the cases the jaw causes a deformation of the circular portion 301 and of the pipe inserted therein, such an for example described in document DE2725280.

[0076] The region 103 of the compression surface of the jaw 3 can have projections arranged on the circumference that generate each one a radial recess with a corresponding extension both in the wall of the cylindrical portion 301 and in the corresponding wall below of the pipe 4. Thus the pipe and the tubular body 1 of the fitting are mechanically locked with each other preventing the two parts from slipping out or from rotating one with respect to the other and thus generating the mere mechanical coupling with each other.

[0077] In FIG. 2 the jaw 3, at part 103 and part 203 coinciding with the cylindrical portions 301 and 401 of the tubular body 1 respectively, has forming projections 303 that deform both the corresponding cylindrical portion 301, 401 of the tubular body 1 and the part of the pipe 4 inside them.

[0078] Typically the deformation of the V profile changes the shape of the cross-section of the pipe 4 and of the cylindrical portion 301, 401 of the tubular body 1 of the fitting while transforming the circular cross-section thereof into a polygonal cross-section for example hexagonal one and with rounded corners.

[0079] Therefore the forming projections 303 of the jaws 3, in the jaw assembly, in the final closing position, form a polygonal forming surface that is at least secant the circular section of the tubular body 1 and of the pipe 4 or even inscribed in said circular section of the tubular body 1 and of the pipe 4 in their condition not deformed yet by the pressing action.

[0080] Since such deformation occurs along annular bands with a reduced width in axial direction also in this case a mechanical coupling of the tubular body 1 on the pipe 4 is generated preventing said two parts from axially slipping out and from accomplishing a relative rotation.

[0081] Obviously as regards the deformation along the annular band or bands at one or both the cylindrical portions 301, 401 these can be also provided combined with each other or changed with each other with reference to the type of jaw for N or V profile as regards the part thereof acting on the bulge.

[0082] With reference to FIG. 4, it shows a preferred embodiment for a fitting according to the present invention made of stainless steel and showing the different dimensions for different diameters of the pipe.

[0083] From the dimensions shown in the table it is possible to define some general relations between individual dimensions of specific parts of the fitting and the diameter thereof that is defined by the diameter of existing pipes.

[0084] Particularly the following parametric characteristics are clear, which are an optimization among needs having opposing effects but necessary to guarantee that the compression of the fitting, both by a tool suitable for pressing M profiles and by a tool suitable for pressing V profiles, leads to identical and optimal results as regards tightness and its duration over time and the indissolubility of the mechanical constraint.

[0085] The most important characteristics are the following ones with reference to the preferred embodiment of FIG. 4:

[0086] the two sides connect with each other by a curved portion having a radius ranging from 1 to 2.5 mm, in particular from 1.25 to 1.95 mm.

[0087] Said radius has a size ranging from 3 to 7% of the diameter of the tubular body.

[0088] Said two side walls that is the two sides of the bulge and of the corresponding groove connect with the corresponding cylindrical portion by a curved flare having equal radii of curvature for said two side walls and ranging from 0.25 to 0.75 mm.

[0089] The radial projection of the annular bulge changes for outer diameters of the cylindrical portion of the fitting from 18 mm to 60 mm, from about 2 to 4 mm, in particular from 2.45 to 3.75.

[0090] The radial projection of the bulge in relation to the outer diameter of the cylindrical portions on the two sides thereof ranges from 5% to 15% of the outer diameter of said cylindrical portions preferably from 6 to 14% of the outer diameter of said cylindrical portions.

[0091] The axial distance between the central axis of the annular bulge and the free edge of the cylindrical portion at the inlet of the fitting ranges from 10 to 16 mm for diameters of the cylindrical portion ranging from 20 to 60 mm.

[0092] Such axial distance is higher than 20% of the outer diameter of the cylindrical portions, preferably ranging from 25 to 60% of the outer diameter of the cylindrical portions of the fitting.

[0093] The thickness of the wall of the fitting is substantially the same for the whole axial length thereof and in the order of magnitude of about 3 mm.