DESCRIPTION

FIELD OF THE TECHNIQUE

The present invention refers to press fittings for coupling to pipes in plastic material (e.g. multilayer type) of the type that can be used in plumbing systems or for transporting gaseous fuels.

STATE OF THE ART

Several types of press fittings for plastic piping are known, which, while having different configurations, share a basic structure shown in Figure 1. The press fitting of Figure 1 includes a fitting body 200, comprising a coupling portion 201 (having a male thread) intended to be connected to a component of the plumbing system, and an insertion portion 202.

The insertion portion 202 is intended to be inserted inside the pipe to be connected to (not shown) and on which a metal sleeve 203 is compressed, by cold deformation obtained with suitable jaws. The insertion portion 202 is provided with ring seals 204 that contact the tube shod on the insertion portion 202. In addition, a matching member 205 is provided for use in properly positioning the compression jaws of the metal sleeve 203.

The press fitting in Figure 1 is of the "straight" type, but can be made in other configurations (e.g., curved at 45°, 90°, or T-shaped). Some possible configurations of known type press fittings are shown in the October 2020 catalog of the same Applicant and related to multi-pin press fittings, RM series: https:/ / static.giacomini.com/ giacomini.com/ catalog/ technical_documentation/ patent/ RM-FITTINGS.pdf.

The Applicant has noted that, in press fittings such as the one shown in Figure 1, the insertion portion 202 has an inside diameter that is significantly smaller than the diameter of the pipe into which it is inserted. Further, the installation procedure for this type of fitting typically requires preparation of the end of the pipe (flaring and calibration) prior to fitting it to the insertion portion 202 which is quite onerous.

In addition, the use of lubricants during installation or the selection of particular shapes, either of the grooves into which the ring gaskets 204 are to be inserted or of the gaskets themselves, do not eliminate the risk of cuts to such gaskets during the fitting of the pipe. Damage to gaskets 204 may result in fluid leaking to the outside.

Document US-A-6866302 describes metal fitting mounted on a hose for transporting hydrogen, air conditioner refrigerant, or automotive fuel. The hose has a body-tube formed from corrugated metal tubing and layers of rubber or resin.

Document DE-A-20212772U1 describes a pressable connection comprising a fitting on which there is a first pressable section in the form of a sleeve and a second pressable section. Between these pressable sections is provided a collar in which a sealing ring is inserted.

Document US-A-2250286 relates to a fitting for fabric, rubber, and possibly metal lined piping and describes a sleeve intended to surround the piping and having a collar which houses a ring.

SUMMARY OF THE INVENTION

The Applicant has noted that conventional press-fittings for plastic tube (single layer or multilayer) have limitations relating to fluid flow rate and safety with respect to outward fluid leakage.

The technical problem addressed by the present invention is to provide a fitting device, of the press-fit type, for plastic tube, that at least partially overcomes the limitations of known type fittings with respect to fluid flow rate in the fitting and safety with respect to outward fluid leakage.

In particular, it forms the object of the present invention to provide a fitting device as defined by claim 1 and particular embodiments thereof described by dependent claims 2-14.

According to another aspect, it is also an object of the present invention to have a fluidic system as defined by claim 15 and particular embodiments thereof as defined by claims 16 and 17.

BRIEF DESCRIPTION OF THE FIGURES

The constructional and functional features of the invention may be better understood from the detailed description which follows, in which reference is made to the attached drawing sheets representing some preferred and non-limiting forms of embodiment, wherein:

- figure 1 shows a longitudinal section of a press fitting of known type;

- figure 2 shows a longitudinal section of an example of a fitting device according to a first embodiment of the present invention;

- figure 3 shows in perspective view an exploded view of a fitting device similar to that of figure 2;

- figure 4 shows in longitudinal section an example of a fitting device in relation to a second form of implementation of the present invention;

- figure 5 shows in perspective view an exploded view of the fitting device analogous to figure 4;

- figure 6 shows the device of figure 4 in side view, assembled.

DETAILED DESCRIPTION

In the present description, similar or identical elements are identified in the various figures by the same numerical reference. Figure 2 and Figure 3 show an example of a fitting device 100 to plastic tube. The fitting device 100 is of the "press fit" type and is employable in fluidic systems such as, typically, plumbing systems (e.g., cooling, heating, and domestic water) or gaseous fuel transport systems, to mechanically connect and fluidically connect one end 4 of a plastic tube with another component (not shown) of the system.

For the purposes of this description, the term plastic tube means both tubes made by one or more layers of plastic material (e.g., polyvinyl chloride, polyethylene, polypropylene) between which are, optionally, arranged glues or adhesive layers, and multilayer plastic tube formed of layers of plastic material (e.g., cross-linked polyethylene), one or more layers of metallic material (e.g., aluminum), and adhesive layers (e.g., glue layers). In particular, multilayer tubes have the outer layer made of plastic material. In addition, in such tubes the innermost layer, i.e., the layer in contact with the fluid, is made of plastic material. In a multilayer plastic tube the metal layers that may be used are internal to the plastic layers. Some examples of types of materials for plastic tubes are: TEX (cross-linked polyethylene); PEX-A1-PEX (cross-linked polyethylene with aluminum layers); PB (polybutylene); PER-T (multilayer polyethylene). Preferably, the plastic tube referred to in the present description is of the smooth type i.e. not corrugated.

Returning to the fitting device 100, this comprises a fitting body 1 having a coupling portion 2 and a tubular portion 3. The coupling portion 2 is configured to mechanically couple with a component (not shown) of the system while also allowing fluid coupling with said component. Such a component, may be, for example, another coupling device, a metal pipe, an inlet or outlet of a pump or boiler, a shut-off valve, etc.

According to the illustrated example, the coupling portion 2 has the outline of a male coupling including a shaped region 7, typically polygonal, having the purpose of providing support planes suitable for housing a tool (typically, a wrench) and an insertion portion 8, which defines within itself a first conduit 6 and has an external thread 5 (i.e., a male thread) .

The tubular portion 3, in fluid communication with the coupling portion 2, is configured to house (in particular, in a second conduit 9) the end 4 of the plastic tube. Preferably, the first conduit 6 and the second conduit 9 have substantially equal diameters and, according to one example, are aligned along a relative longitudinal axis A-A. The first conduit 6 opens onto the second conduit 9 by means of an intermediate passage 10 which has, for example, a reduced diameter compared to that of the first conduit 6.

According to the example of the figures, the polygonal-shaped region 7 has a maximum outer diameter greater than the outer diameter of the tubular portion 3 and is connected to the tubular portion 3 by an annular groove 11. The tubular portion 3 is provided with an insertion opening 12 for the end of the plastic tube 4.

Furthermore, the tubular portion 3 of the fitting body 1 is plastically deformable, (in particular, cold deformable) under the action of compression exerted by suitable pressing tools, such as, for example, jaws, and encircles an outer wall 13 of the tubing end 4.

Note that, according to a first form of implementation (to which Figure 2 refers), the fitting body 1 (comprising the coupling portion 2 and the tubular portion 3) is manufactured in one piece. In this case, the coupling portion 2 and the tubular portion 3 are made of the same material. The manufacturing materials of the fitting body 1, may be metals or metal alloys, such as, for example, steel or stainless steel, copper and its alloys (e.g., brass), bronze, cupronickel.

For example, the one-piece fitting body 1 is made by at least one of the following manufacturing processes or combinations thereof: molding (such as, injection molding), machining, casting, cold working such as rolling, drawing, clinching, hydroforming, magnetoforming, or variations thereof. The inner surface of the tubular portion 3 may be smooth, as depicted in Figure 2, or may be shaped to provide sealing reliefs (e.g., teeth) intended to act on the outer wall 13 of the end of the plastic tube 4. Note that the flat surface of the tubular portion 3 of the fitting body 1 allows for the affixing of markings, using different engraving technologies, bearing data of the product or tubing 4 to which it can be fitted.

In addition, the fitting device 100 includes a sleeve element 14, to be arranged internally to the tubular portion 3 and configured to be surrounded by the end of the plastic tube 4 when it is inserted into the second conduit 9. The sleeve element 14 includes a cylindrical wall 23 provided with a first opening 17 and an opposing second opening 18.

Further, according to one example, the sleeve element 14 is provided, around the second opening 18, with a stop ring 15 that extends externally and perpendicularly to the cylindrical wall 23 of the sleeve element. The stop ring 15 is configured to abut an inner annular wall 16 of the tubular portion 3, such that the sleeve element 14 finds itself facing and in fluid communication with the passage 10.

For example, the sleeve element 14 has an inner diameter substantially equal to the inner diameter of the intermediate passage 10 of the coupling portion 2.

The sleeve element 14 may be manufactured from copper or alloys thereof (e.g., brass), steel, stainless steel, or a plastic material.

The outer surface of the sleeve member 14 may be smooth, as depicted in Figure 2, or may be shaped to provide for sealing reliefs (e.g., teeth).

The connecting device 100 may advantageously include a dielectric separator 19 (e.g., of a toroidal or cylindrical shape) to be disposed between the end of the tube 4 (when inserted into the second conduit 9) and a face of the stop ring 15.

The dielectric separator 19 allows to limit the generation of eddy currents, due to the junction of elements with different electronegativity (such as, for example, copper alloys or steel of the junction body 1 and the aluminum present in the end of the tube 4). The dielectric separator 19, which also serves as an anti-slip device for the sleeve element 14, can typically be made of an elastomeric or plastic material.

In addition, the fitting device 100 preferably includes a match element 20 (for example, a shaped ring) for correct positioning of the jaws, which may be made of a plastic or metallic material. The matching element 20 may be in different colors to provide a visual indication of the size of the tubular portion.

It should be noted that, advantageously, the fitting device 100 of Figures 2 and 3 does not necessarily require sealing elements to prevent leakage of fluid from the end of the tubing 4 to the outside of the fitting device. In particular, sealing elements may be avoided to be interposed between the sleeve element 14 and the end 4 of the tubing nor between the end of the tubing 4 the tubular portion 3.

The fitting device 100 may be provided pre-assembled or may be assembled during installation.

In either case, the sleeve member 14 is coaxially inserted into the second conduit 9 by bringing the stop ring 15 against the inner wall 16 of the fitting body 1.

Then, the dielectric separator 19 is inserted into the second conduit 9 around the sleeve element 14, and against the stop ring 15 so that it acts as a retaining element.

A cavity for housing the end of the plastic tube 4 is formed between the outer surface of the sleeve element 14 and the inner surface of the tubular portion 3.

The matching member 20 is disposed externally to the coupling body 1 at the annular groove 11 and such that it extends, for example, partially over the tubular portion 3 and partially over the coupling portion 2.

For installation of the coupling device 100, the end 4 of the plastic tube is coaxially mounted on the sleeve member 14 such that it is disposed between the sleeve member itself and the tubular portion 3. In particular, the end 4 is inserted until it contacts the dielectric separator 19.

Next, with suitable jaws surrounding the tubular portion 3, compression is exerted on the portion itself so that it deforms (reducing its radial extension) until it encircles the outer wall 13 of the end 4 of the plastic tube.

Therefore, the end 4 of the plastic tube is pressed against the outer surface of the sleeve element 14 which, therefore, acts as a reinforcing element that prevents a collapse of said tubing. The deformation to which the tubular portion 3 of the fitting body 1 is subjected places it in integral contact with the end of the tube 4, thus ensuring a seal. In particular, the tubular portion 3 is in contact with the outer wall 13 of the tube which is a layer of plastic material.

The tubing end 4 is therefore mechanically coupled and in fluid connection with coupling device 1. The coupling portion 2 of the coupling body 1 may be coupled to another component of the system, as already mentioned.

It should be noted that in the fitting device 100, the tubular portion 3 is both a structural element of the fitting itself and the press fit element that realizes the grip on the plastic tube.

Figures 4-6 refer to a version of the fitting device 100 in which the tubular portion 3 and the coupling portion 2 of the fitting body 1 are not manufactured as one piece, but are manufactured separately and then connected to each other. In such a case, the coupling portion 2 and the tubular portion 3 are connected so as to obtain a permanent connection that ensures a tight connection between said portions 2 and 3.

According to this embodiment, the coupling portion 2 is fabricatable in plastic material, in addition to the materials and techniques described above with reference to the fabrication of the entire coupling body 1 and Figures 2 and 3. The tubular portion 3 can be made from metal or metal alloys (preferably, stainless steel). Said tubular portion 3 may be obtained from a tube, strip or sheet metal, by welding or by cold working or deformation, such as deep drawing, rolling, shearing, sizing. The tubular portion 3 may also be obtained by processing such as welding, brazing, welding/brazing.

The permanent connection between the tubular portion 3 and the coupling portion 2 can be obtained during production, for example, by at least one of the following techniques: welding, brazing, braze welding, or cold forming techniques (preferably, magnetoforming) .

For example, the coupling portion 2 has an annular portion 21 (i.e., an outer wall of the portion defining the intermediate passage 10) to which the tubular portion 3 is connected.

Note that, advantageously, sealing elements 22 (e.g., gaskets, Orings) may be disposed between the annular portion 21 and the tubular portion 3.

With respect to the embodiment of Figures 4-6, note that the user will receive the fitting device 100 in which the tubular portion 3 is already permanently connected (i.e., the two portions are not de-assemblable) to the coupling portion 2.

The fitting device 100 (in the two described forms of implementation) is realizable in different sizes for coupling to different types of piping or system components. For example, the fitting device 100 is suitable for coupling to plastic piping events the following outer diameters: 16.00 mm; 20.00 mm; 26.00 mm; 32.00 mm; 40.00 mm; 50.00 mm and 63.00 mm.

Coupling portion 2 may have an external thread, as in Figures 2 and 4, or it may have an internal thread (female thread) .

Moreover, the coupling portion 2 can have a geometry such as to allow the realization of connection devices having all the configurations currently available on the market. In particular, with such a basic structure it is possible to realize the different configurations shown in the aforementioned Applicant's catalog relating to multi-pin press fittings, RM series.

In the first actuation form shown by Figures 2 and 3 and in the second actuation form of Figures 4-6, the tubular portion 3 is cylindrical, prior to the deformation action, and is directly in contact with the outer wall 13 of the tubing end 4 without the presence of any interposed teeth or gaskets. Nevertheless, it should be noted that, although not strictly necessary, it is possible to provide, both for the first embodiment of Figures 2 and 3 and for the second embodiment of Figures 4-6, that the tubular portion 3 is provided with a seat, obtained in its inner part, for housing a sealing element, such as a gasket or an Oring.

According to the example of Figures 2-4, the fitting device 100 has a straight (i.e., straight) configuration but, according to a particular implementation form, the coupling portion 2 could be curved, for example at 45° or 90°.

With respect to other examples, it is possible to implement a configuration (referred to as press-press) in which the coupling portion 2 is also connected (in one piece or permanently) to another tubular portion 3. In particular, according to this press-press configuration, the coupling portion 2 is interposed between two tubular portions 3, each available to accommodate relative ends of tubing 4 to be connected. Each of the two tubular portions 3 includes a corresponding sleeve 14 and a corresponding dielectric separator 19 and is provided with a corresponding matching element 20, as described above. The two tubular portions 3 may have the same dimensions or different dimensions of the corresponding inner conduits 6.

According to another example, the connection device of the type described above may provide that the coupling portion 2 (intermediate to the two tubular portions 3) is straight or is curved, for example, at 45° or 90°.

In accordance with another embodiment, the coupling portion 2 is shaped to form a curve (of 90°) and is integral with a bracket for wall installation.

According to a further embodiment, the coupling portion 2 may be of the T-type (not shown) and have three ports at relative ends. According to a particular configuration, all three ports of said T-type coupling portion 2 are connected (in a manner analogous to that described above for Figures 2 and 4) to a respective tubular portion 3, provided with a corresponding sleeve 14, a corresponding dielectric separator 19 and a corresponding matching element 20.

In accordance with another configuration, the T-type coupling portion 2 has two of the three ports coupled to respective tubular portions 3 while the third port is a threaded connection, for example analogous to the coupling portion 2 of figure 3 (also in a female threaded version). It is also possible that a shut-off valve is integrated at one of the three ports.

The above-described fitting device 100 is advantageous over conventional fittings.

In particular, the use of a structural portion (i.e., the tubular portion 3) of the same fitting body 1, and not a separate sleeve as is the case with conventional fittings for plastic pipe, as the press element, allows for a passage for the fluid within the fitting of increased diameter. In fact, in conventional fittings the pipe to be connected is shod over an insertion portion of the fitting that has a significantly reduced inner diameter compared to that of the pipe.

In contrast, the sleeve element 14 of the fitting device 100 can be made with an inner diameter that is only slightly smaller than the pipe diameter.

Furthermore, the fitting device 100 is not very sensitive to different profiles of the pressing jaws (i.e., it is multi-press ) since it can be used with different types of jaws.

The solution described is also easy to install. In fact, it is not necessary to countersink the tube to be fitted on the sleeve element 14, nor to calibrate it (unless it is ovalized). Moreover, since elastomeric sealing elements are not strictly necessary between the sleeve element 14 and the end of the pipe 4 to be connected, the use of lubricants to facilitate insertion and sliding on the sealing elements (Oring) is not required.

In addition, contrary to the fittings of known art, there is no risk of breakage of the sealing elements (since, here, they are not necessarily provided) on which the pipe is fitted.

List of components shown in the drawings

- fitting device 100

- fitting body 1

- coupling portion 2

- tubular portion 3

- plastic tube end 4

- external thread 5

- first conduit 6

- shaped region 7

- insertion portion 8

- second conduit 9

- intermediate passage 10

- annular groove 11

- insertion opening 12

- outer wall 13

- sleeve element 14 - inner ring wall 16

- first opening 17

- second opening 18

- dielectric separator 19 - matching element 20

- annular welding portion 21

- sealing gasket 22

- cylindrical portion 23