MECHANICAL FITTINGS FOR CPVC

Abstract

The present invention provides a mechanical coupling for connecting pipes or for securing a pipe. The coupling comprises a main coupling body (10, 210, 310) extending axially between a body end and an open end (11) defining an insertion space for a pipe, adapted to close on a pipe, a crimping ring (30) mounted on the main coupling body for tightening the main coupling body on the pipe. The crimping ring (30) comprises a ring body (31) in the form of an open ring connected by a crimping ear (36) projecting radially outwardly from the ring body (31), the crimping ear (36) being deformable to close the crimping ring on the pipe during the crimping process. The mechanical coupling is provided with an anti-deformation device to prevent deformation of the pipe inserted therein during crimping. An assembly method is also provided.Figure for abstract: Figure 1.

Description

Title of the invention: MECHANICAL FITTINGS FOR CPVC

[0001] The present invention relates to the field of mechanical fittings. In particular, the present invention relates to a mechanical fitting for connecting pipes or for securing a pipe, an assembly of a mechanical fitting and a pipe, and a method of assembling a mechanical fitting and a pipe. Prior art

[0002] Crimp or press fittings, also called press fittings, which allow pipes to be connected by compression and deformation using one or two sleeves, are well known in the field of installation of pipes, piping and pipeline systems, for example for water, gas or heating.

[0003] Press fittings are used to connect not only metal pipes, but also plastic pipes or metal-plastic composite pipes. They are used to connect suitably arranged pipe sections, with their connecting parts being inserted into the ends of the pipes to be connected, where they are then deformed, crimped or pressed. They are fixed in certain areas, for example with the help of pressure sleeves on the parts, using so-called system compression tools which usually have interchangeable pressure jaws.

[0004] Tube, pipe or conduit systems are assembled in several steps: the pipes are first inserted into a fitting, then the fitting is crimped to ensure good mechanical strength and a watertight installation. Compression is essentially pressure exerted on the fitting sleeve - also called a pressure or crimping sleeve - which causes the fitting to deform or shape to the pipe inserted into it. The pressure is usually applied to the fitting using a pressure jaw acting as a compression tool. These pressure jaws exert radial pressure on the fitting material to cause interaction with the surface of the pipe(s) to be connected, thus achieving a reliable connection and a reliable seal.

[0005] Other fittings, such as those used for example for hoses such as in gardening equipment, use a threaded engagement to allow crimping of the hose and rely on a portion of the fitting engaging the hose.

[0006] In both cases, the connection is based on a deformation of the pipe to be connected, in most cases, using an insert placed inside the pipe to be connected.

[0007] For different pipe arrangements, pressure fittings can be designed as curved, angular or T-shaped pieces, with typically one, two or three connecting pieces provided.

[0008] The pipe or tube may be mono-material and composed of thermoplastic materials, including but not limited to PE, PB, PEX, PERT, PER ... or Composite (multi-material pipe structure) with different layers of functional materials (PEX, PERT, PVDF, aluminum ...).

[0009] It is known to use pressure fittings made entirely of plastic, or pressure fittings whose fitting body is made of metal (brass, stainless steel, etc.), or thermoplastic (PVC, PPSU, PVDF, PPS), which can also be reinforced with fiberglass reinforcement.

[0010] However, with the introduction of c-PVC material pipes, compression fittings relying on the deformation of the material for connection do not give good results. This is because c-PVC has different properties and is more brittle than other materials and c-PVC is more brittle over time.

[0011] One solution that has been proposed is solvent bonding. However, regulations are evolving and it will be necessary to avoid adding solvents.

[0012] It is therefore necessary to find another solution for crimp fittings, in order to avoid the use of solvent.

[0013] An object of the present disclosure is to provide a mechanical fitting for connecting CPVC, PVC and PVC-U piping systems for hot and cold water installations, as well as for hot and cold pressurized applications. Summary of the invention

[0014] To this end, the present invention provides a mechanical coupling for connecting pipes or for securing a pipe, comprising a main coupling body extending axially between a body end and an open end defining an insertion space for a pipe, adapted to close onto a pipe, and a crimping ring mounted on the main coupling body for clamping the main coupling body onto the pipe. The crimping ring comprises an open ring-shaped ring body connected by a crimping ear projecting radially outwardly from the ring body, the crimping ear being deformable to close the crimping ring onto the pipe during the crimping process. The mechanical coupling is provided with an anti-deformation device to prevent deformation of the pipe inserted therein during crimping.

[0015] The present invention provides a mechanical connection designed to use friction instead of compression to provide a connection between the mechanical connection and a pipe inserted into the latter. This is advantageous especially for pipes that are fragile, such as PVC pipes or pipes made of material from the PVC range, such as c-PVC, PVC-U, etc.

[0016] A mechanical connection based on friction aims not to deform the pipe during assembly, but to create a friction interface at the interface of the pipe and the crimping ring, capable of resisting a tearing force during operation. Therefore, an anti-deformation device makes it possible to avoid deformation of the pipe inserted therein during crimping. The deformation of the pipe remains within the limits of the ovality of the pipe. The ovality of the pipe is defined as the difference between a maximum diameter and a minimum diameter of the pipe along its length. For example, for a c-PVC pipe with a nominal diameter of 63 mm, the ovality is approximately 0.1 to 0.15 mm depending on the pipe storage conditions. The maximum diameter can therefore be 63.15 mm.

[0017] According to one aspect, the connector body comprises at least one axial slot, the anti-deformation device comprising the at least one axial slot. The axial slot of the connector body allows radial movement of the main connector body. During crimping, the main connector body can deform against the pipe during crimping and adapt to the shape of the pipe which may have a cross-section which is not perfectly round, due to the ovality of the pipe. This avoids the concentration of forces on the pipe by allowing a good distribution of the load on the pipe.

[0018] In one aspect, the fitting body is provided with a reinforcing element under the ring receiving surface, such as a metal open ring, particularly located between the main fitting body and the pipe when assembled. This is advantageous particularly for large diameter pipes.

[0019] In one aspect, the inner surface of the coupling body includes circumferential recesses that extend radially within the main coupling body, and the inner surface forms a friction surface over a contact length as part of the anti-deformation arrangement. This creates a friction interface to hold the pipe within the mechanical coupling.

[0020] According to one aspect, an external sleeve is provided on the compression ring to axially retain the crimp ring on the main connector body.

[0021] In one aspect, the crimping ring is provided on a ring receiving portion of the main body extending between the open end and an outer radial projection on an outer body surface of the main body.

[0022] According to one aspect, the main body has an internal radial rib at its body end opposite the free end, and the external radial projection is axially spaced from the internal radial rib.

[0023] In one aspect, a seal is provided within a seal housing in the main fitting body located axially between the inner radial rib and the ring receiving portion. The seal may have an inner triangle shape for insertion of the pipe, with an insertion surface 56 facing the open end of the fitting, and wherein on the rear side of the seal axially opposite the insertion surface, the seal has a rear surface having a step shape. The inner triangle shape facilitates insertion of the pipe into the mechanical fitting. This shape of the rear surface of the seal allows the seal to deform around the pipe by allowing the seal to move into the additional space provided behind the step-shaped rear surface.

[0024] In one aspect, the seal is a rubber seal. The body may be polymer or composite.

[0025] The present invention provides an assembly of such a mechanical coupling and a pipe, wherein the main coupling body and the pipe have a minimum axial contact length according to the following equation:

[0026] The contact length between the pipe and the ring is the contact length necessary to create enough friction to hold the pipe with the mechanical connection against pull-out forces.

[0027] According to one aspect, after closing the crimping ring, the crimping ring is provided on a ring receiving portion of the main fitting body extending between the open end and an outer radial projection on a main body outer surface, and / or the pipe outer diameter is reduced by at most 0.5%. In other words, the pipe is not deformed by crimping and the pipe inner diameter is not reduced.

[0028] The present invention provides a method of assembling such a fitting and a pipe, comprising the following steps:

[0029] - insert the pipe into the main fitting body, preferably up to the rib internal radial,

[0030] - close the ear of the crimping ring to press the main fitting body against the pipe, the pipe remaining undeformed after closing the crimping ring, the external diameter of the pipe being reduced by less than 0.5% after crimping.

[0031] According to one aspect, during closure of the crimp ring, the seal deforms against the main fitting body on one side and against the rigid pipe on the other side, in particular a rear surface of the seal having a step shape deforms around the pipe to create the seal. Brief description of the figures

[0032] Other features and advantages of the invention will become more clearly apparent upon reading the description of several presently preferred embodiments, provided by way of example only, with reference to the attached drawings, in which:

[0033] [Fig.l] shows a sectional view of a mechanical connection before assembly according to a first aspect of the present disclosure,

[0034] [Fig.2] shows a sectional view of a mechanical connection before assembly according to another aspect of the present disclosure,

[0035] [Fig. 3] shows an element for a mechanical connection according to the present disclosure,

[0036] [Fig.4] shows a seal for a mechanical connection according to the present disclosure,

[0037] [Fig.5] shows a seal for a mechanical connection according to the present disclosure,

[0038] [Fig.6] shows a seal for a mechanical connection according to the present disclosure,

[0039] [Fig.7] is a sectional view of a mechanical connection before assembly according to a first aspect of this disclosure,

[0040] [Fig.8] is a mechanical connection before and after crimping according to the present disclosure. Detailed description

[0041] In the figures, identical elements are identified by the same reference numbers.

[0042] [Fig.l] shows a mechanical fitting 1 for connecting a pipe (not shown in [Fig.l]) according to one aspect of the present invention. The pipe may be, for example, a pipe for / in a piping system for fluid installations inside buildings.

[0043] The pipe may be, for example, a pipe for / in a piping system for fluid installations inside buildings. The pipe may be made of CPVC, PVC and PVC-U for hot and cold water installations, in particular for pressurized hot and cold applications.

[0044] The connector 1 may form one side of a connector having a similar or other type of connector at its other end or side. The connector may also be placed at an orifice of a fluidic device to connect a hose thereto.

[0045] In the example of [Fig.l], the left portion of the connector is shown in the assembled state, while the right portion shows an exploded view of the connector. The connector may allow the connection of two pipes on both sides, but this is not limiting of the invention. The connector may form one side of a connector having a similar or other type of connector at its other end or side. The connector may also be provided at a port of a fluidic device for connecting a pipe thereto.

[0046] The mechanical connection 1 comprises a main connection body 10 intended to receive the pipe.

[0047] The main connector body 10 has a body outer surface 14 and a body inner surface 15. The main connector body 10 defines a pipe insertion space extending in an axial direction XX, between an open end 11, i.e. the end where the pipe is inserted, and an internal radial rib 12 extending radially inward from the body inner surface 15. The internal radial rib 12 is intended to stop the pipe inserted into the main connector body 10.

[0048] The mechanical fitting 1 ensures a secure connection between c-PVC, PVC and PVC-U piping systems.

[0049] A crimping ring 30 is provided on the main connector body 10, to be tightened onto the main connector body and the pipe, when the pipe is inserted into the main connector body. Tightening of the crimping ring 30 causes the main connector body to be tightened onto the pipe to hold the pipe in place, against a pull-out force.

[0050] As can be seen, the crimping ring 30 is placed on a ring receiving portion 18 of the main connector body 10 extending between the open end 11 and an outer radial projection 19A extending radially away from the outer body surface 14.

[0051] The crimping ring 30 comprises an open ring-shaped ring body 31 connected by a crimping ear 36 projecting radially outwardly from the ring body 31. In the example described, there is one crimping ear, but it is possible to have two or more crimping ears.

[0052] As is known in the prior art, the crimping ear 36 is deformed and the annular ends of the open ring body move towards each other during the crimping process to close the ring body 31.

[0053] However, it is important to understand that prior art press fittings rely on deformation of the pipe, i.e. upon closing the press ring, the fitting body has been designed to deform the outer surface of the pipe inserted into the main fitting body, with radial recesses or sockets penetrating the pipe wall to a depth corresponding to the length of the radial recesses.

[0054] It is not possible to rely on pipe deformation with the material c-PVC, PVC, PVC-U. PVC is brittle and cannot withstand deformation. The pipe will only break during a prior art crimping process. It should be noted that the present disclosure focuses on c-PVC, as it is the most more resistant to high pressure and high temperature. However, brittleness is similar for all PVC-based materials.

[0055] To solve this problem of material brittleness, it must be ensured that the pipe will not undergo deformation. This is therefore a challenge for press fittings that otherwise rely on the deformation of the pipe for the crimping process. It is important to note that the pipe must not deform under the effect of the fastening force. In fact, the mechanical fitting 1 is designed to reduce the load on the pipe to prevent the pipe from breaking under the load.

[0056] According to the present disclosure, the crimping ring 30 is designed so that the complete closure of the crimping ear 36 does not cause the pipe inserted therein to deform. However, instead of relying on compression to deform the pipe and assemble the fitting and the pipe, the present disclosure proposes to rely on friction. Thus, the fitting is designed to allow a certain degree of deformation of the fitting so that the resulting pressure provides the necessary friction, without however inducing deformation in the pipe or tube to be attached.

[0057] In other words, instead of relying on compression to connect the pipe, the present disclosure proposes to rely on friction.

[0058] Indeed, prior art press fittings for PE pipes are based on pipe deformation and reduction of the outer diameter in order to hold the pipe against the pull-out force generated by the internal operating pressure. For example, the inventors measured the pipe deformation with different existing models. They measured a reduction in pipe diameter from 32 to 30.6 mm, which is equivalent to 1.4 mm in pipe thickness. Thus, on average, in the prior art, the pipe thickness is reduced by 1.4 mm, which is equivalent to 46% pipe wall deformation or thickness reduction.

[0059] On the other hand, PVC, c-PVC or PVC-U pipes are brittle and do not withstand deformation. It is therefore not possible to rely on pipe compression and deformation to deform the pipe and fix the fitting, as was the case with the mechanical fitting of the known prior art. It should be noted that this document focuses on c-PVC, as it is the material most resistant to high pressure and temperature. The brittleness is, however, similar for all PVC-based materials.

[0060] Similar measurements were made for a c-PVC pipe with a nominal diameter of 63 mm and an ovality, which is the difference between the maximum and minimum pipe diameters, of about 0.1 to 0.15 mm depending on the pipe storage conditions. Thus, the maximum diameter can be 63.15 mm. With the mechanical connection of the present disclosure, which is based on friction crimping, the pipe diameter is reduced from 63 to 62.7 mm, which is equivalent to a reduction of diameter of 0.30 mm or 0.45 mm taking into account ovality and a possible maximum diameter. This equates to 0.47% pipe deformation or diameter reduction. Instead of a traditional compression fitting where the pipe diameter is reduced by at least 10% to create a secure connection, the mechanical fitting of the present disclosure has a pipe deformation of no more than 0.5%. This deformation is negligible and is considered a surface deformation only, with no deformation of the pipe itself.

[0061] The friction between the pipe and the main fitting body is optimized to be greater than the pull-out force applied to the pipe. A minimal friction force is required to hold the pipe against the pull-out force due to internal pressure and external force. The pull-out force on the pipe is typically a function of the operating pressure and the pipe diameter.

[0062] When the crimping body 31 is closed, the internal surface 15 of the main fitting body 10 defines a friction surface to allow good gripping of the pipe.

[0063] The coefficient of friction^, in the steady state can be given by the following equation:

[0064] where L represents the friction contact length, therefore the contact surface between the pipe and the fitting body, m is the mass, and therefore also represents the load due to internal pressure.

[0065] Therefore, a minimum contact length must be considered to create a friction force to hold the pipe against the pull-out force, and the crimping area must be determined to ensure an acceptable distribution of pressure on the pipe.

[0066] There is a relationship between the steady-state coefficient of friction, which depends on the load or pressure level exerted on the pipe, and the contact area between the pipe and the fitting body.

[0067] The inventors have determined that the minimum axial contact length L at the interface between the pipe and the clamping ring necessary to distribute the stress generated by the tearing force between the pipe and the ring acting on the pipe, must satisfy the following equation:

[0068] where Pd is the pressure, L is the axial contact length and DN is the nominal diameter of the pipe.

[0069] For example, according to NF EN ISO 15877-5 2009-05, the design pressure generated on the c-PVC pipe of any Type II class must be less than or equal to 2.86 MPa. Under an operational pressure of 25 bar, a fitting with a diameter of 63 mm must resist a pull-out force generated by a pressure of 4.7 MPa. Applying the above equation, 25.88 mm is the minimum length of the surface to not generate a load greater than 2.86 MPa on the pipe. On the other hand, the minimum axial contact length is required to be considered as creating a friction force to hold the pipe against a pull-out force.

[0070] For example, the inventors manufactured a mechanical fitting with a main fitting body having an internal diameter of 63 mm and a contact length of 25.88 mm between the pipe and the main fitting body. The surface roughness of the main fitting body on the pipe was 1 mm, due to the radial recesses 17. The pipe pull-out force is measured = 11,837 N, and the friction coefficient is as follows: ,«_.&= / _ / r 1 / or ce)= 1183 7 / (IVarm ai / orce)

[0071] After closing the crimping ring 30, the inner surface of the outer casing of the main connector body 10 has a diameter equal to or greater than the outer diameter of the pipe, or at least equal to the diameter of the pipe taking into account the ovalization of the pipe, with a reduction in pipe diameter of less than 0.5% after crimping.

[0072] The design of the crimping ring 30 with respect to the pipe dimension is a first anti-deformation characteristic.

[0073] A plurality of internal circumferential recesses or radial recesses 17 extending around its internal circumference, inside the main fitting body 10, are used to provide a roughened surface between the pipe and the main fitting body. A roughened surface instead of a smooth surface helps to hold the pipe and prevent slippage or translation of the pipe relative to the mechanical fitting. The pipe must not slip relative to the mechanical fitting, during tightening of the fitting and subsequently.

[0074] The internal radial recesses 17 allow a homogeneous distribution of the crimping load on the pipe.

[0075] To avoid local concentration of the load, the main connector body 10 is also provided with at least one axial slot 61. The at least one axial slot 61 allows radial movement of the main connector body. During crimping, the main connector body 10 can deform against the pipe during crimping and adapt to the shape of the pipe which may have a cross-section that is not perfectly round. The axial slot further prevents deformation of the pipe if the The shape of the main fitting body does not perfectly match that of the pipe. The axial slots are another anti-deformation element.

[0076] The crimping ring 30 is mounted on the main connector body 10, on a ring receiving portion 18 of the external surface 14 of the main connector body 10.

[0077] In the example of [Fig.l], the ring receiving portion 18 is formed by a recess delimited by a first projection 19A and a second projection 19B extending away from the external surface of the main fitting body. The second projection 19B is located at the open end 11 of the main fitting body. The distance between the first radial projection 19A and the second radial projection 19B corresponds to the width of the crimping ring 30.

[0078] By this arrangement, the crimping ring 30 is axially fixed to the main fitting body and can rotate freely around the main fitting body. This is advantageous for the user because it allows the fitting to be positioned and the pipe to be inserted in any position, and the crimping ring to be rotated into a position in which it is easier for the user to crimp the fitting.

[0079] An outer sleeve 40 is provided to cover the crimping ring 30 and protect the crimping ring 30. The outer sleeve 40 has a first internal radial projection 41A and a second internal radial projection 41B for securing the outer sleeve 40 to the main fitting body 10. The first internal radial projection 41A and the second internal radial projection 41B can be clipped onto the first radial projection 19A and the second radial projection 19B.

[0080] In the example of [Fig.l], the crimping ring 30 is held in axial position in the ring receiving space 18 by the first and second radial projections 19A, 19B. The outer sleeve 40 has only a covering function. As will be detailed in [Fig.7], the outer sleeve may have the function of holding the compression ring in the ring receiving portion.

[0081] As shown in [Fig.l], a seal 50 is provided within a seal housing 51 in the main body. The seal 50 is best seen in Figures 4 to 6.

[0082] The seal 50 has an interface 52 with the pipe and an interface 54 with the main body 10. The seal 50 will deform against the main body on one side and against the rigid pipe on the other, thus providing the clamping function.

[0083] The seal 50 also contributes to friction. In this respect, the seal is a rubber seal.

[0084] The seal is not an O-ring but is designed to interact and deform around the pipe. It is a banana type seal.

[0085] The joint 50 has an internal triangle shape for pipe insertion, with an insertion surface 56 facing the open end of the fitting, thus the pipe when the pipe is inserted. The insertion surface 56 facilitates pipe insertion, as shown in [Fig.4], before pipe insertion (upper part), during pipe insertion (middle part) and after pipe insertion (lower part).

[0086] On the rear face of the seal axially opposite the insertion surface, the seal 50 has a rear surface 57 having a step shape. This surface creates an interface between the pipe inserted into the fitting and the seal, which ensures sealing. The step-shaped rear surface 57 provides space for the seal and thus allows the seal to deform around the pipe to create the seal. The deformed seal is illustrated in [Fig.4], after insertion.

[0087] [Fig. 2] shows a mechanical connector 201 for connecting a pipe (not shown in [Fig. 1]) according to another aspect of the present invention. The pipe may be, for example, a pipe for a piping system for fluid installations inside buildings.

[0088] The main connector body 210 has an outer body surface 214 and an inner body surface 215. The main connector body 210 defines a pipe insertion space extending in an axial direction XX, between an open end 211, i.e., the end where the pipe is inserted, and an inner radial rib 212 extending radially inward from the inner body surface 215. The inner radial rib 212 is intended to stop the pipe inserted into the main connector body 210.

[0089] A crimping ring 230 is provided on the main connector body 210, on a ring receiving portion 218 of the main connector body 210 extending between the open end 211 and an outer radial projection 219A extending radially away from the body outer surface 214.

[0090] The crimping ring 230 comprises a ring body in the form of an open ring connected by a crimping ear 236 projecting radially outwardly from the ring body. The crimping ear 236 is deformed and the annular ends of the open ring body approach each other during the crimping process to close the ring body.

[0091] Like the crimping ring 30 of the mechanical fitting of [Fig.l], the crimping ring 230 is designed so that the complete closure of the crimping ear 236 does not cause the deformation of the pipe inserted therein. When the crimping ring 230 is closed, the internal surface 215 of the main fitting body 210 defines a friction surface to allow good tightening of the pipe.

[0092] Indeed, the pipe is fragile and does not support deformation. It is therefore not possible to rely on the compression and deformation of the pipe to deform the pipe and secure the fitting, as was the case with the known prior art mechanical fitting. Instead, the crimp fitting must rely on friction due to the c-PVC material. C-PVC is brittle and will only break during a prior art crimping process.

[0093] While in the mechanical fitting 1 of [Fig.l], a plurality of internal circumferential recesses or radial recesses 17 have been provided on the inner surface of the main body to create a rough friction surface, in the mechanical fitting 201 of [Fig.2], a reinforcing member 270 is inserted under the main body, and the radial recesses 217 are provided on the inner surface of this reinforcing member (see [Fig.3]).

[0094] The reinforcing element 270 is an open ring, which may be metallic.

[0095] The friction surface is the inner surface of the reinforcing element 270, provided to hold the pipe and prevent slippage or translation of the pipe relative to the mechanical connection. The pipe must not slip relative to the mechanical connection, during tightening of the connection and subsequently.

[0096] After closing the crimping ring 230, the inner outer casing surface of the main fitting body 10, with the reinforcing element 270 with a body diameter equal to or greater than the outer diameter of the pipe. The minimum axial contact length between the reinforcing element 270 and the pipe is 25.88 mm. When fully closed, for a pipe with a diameter of 63 mm, the main fitting body has a maximum inner diameter of 63 mm.

[0097] The design of the crimp ring with the correct dimension when fully closed relative to the pipe dimension is an anti-deformation feature.

[0098] To distribute the load evenly along the pipe and avoid local concentration of the load, the main connector body 210 is provided with at least one axial slot 261, which allows radial movement of the main connector body 210. The reinforcing element 270 is also an open ring. During crimping, the main connector body 10 and the reinforcing element can deform against the pipe during crimping and adapt to the shape of the pipe which may have a cross-section that is not perfectly round. The axial slot further prevents deformation of the pipe if the shape of the main connector body does not perfectly match the shape of the pipe.

[0099] The crimping ring 230 is mounted on the main connector body 210, on a ring receiving portion 218 of the outer surface 214 of the main connector body 210. The ring receiving portion 218 is defined by a first radial projection 219A and a second projection 219B extending from the outer surface of the main connector body. The second projection 219B is located at the open end 211 of the main fitting body. The distance between the first radial projection 219A and the second radial projection 219B corresponds to the width of the crimping ring 230.

[0100] The crimping ring 230 is axially fixed on the main fitting body and can rotate freely around the main fitting body. This is advantageous for the user because it allows the fitting to be positioned and the pipe to be inserted in any position, and to rotate after the crimping ring into a position in which it is easier for the user to crimp the fitting.

[0101] A seal 250 is provided within a seal housing 251 in the main body. The seal 250 is similar to the seal 50 of the mechanical connection 1 of [Fig.l].

[0102] [Fig.7] shows a mechanical connection 301 for connecting a pipe (not shown in [Fig.l]) according to another aspect of the present invention, and [Fig.8] shows the mechanical connection 301 with a pipe according to another aspect of the present invention. The pipe may be, for example, a pipe for / in a piping system for fluid installations inside buildings.

[0103] The main connector body 310 has an outer body surface 314 and an inner body surface 315. The main connector body 310 defines a pipe insertion space extending in an axial direction XX, between an open end 311, i.e., the end where the pipe is inserted, and an inner radial rib 312 extending radially inward from the inner surface of the body 315. The inner radial rib 312 is intended to stop the pipe inserted into the main connector body 310.

[0104] A crimping ring 330 is provided on the main connector body 310, on a ring receiving portion 318 of the main connector body 310 extending between the open end 311 and an outer radial projection 319A extending radially away from the body outer surface 314.

[0105] The crimping ring 330 comprises an open ring-shaped ring body connected by a crimping ear 36 projecting radially outwardly from the ring body. Like the crimping rings 30, 230 of the mechanical fittings of Figures 1 and 2, the crimping ring 330 is designed so that fully closing the crimping ear 336 does not cause deformation of the pipe inserted therein. When the crimping ring 330 is closed, the inner surface 315 of the main fitting body 310 defines a friction surface to allow good grip of the pipe over a friction length, as for the mechanical fittings of Figures 1 and 2.

[0106] After closing the crimping ring 330, the inner outer casing surface of the main fitting body 310, with the reinforcing member, has a body diameter equal to or greater than the outer diameter of the pipe. Therefore, the crimping ring is configured such that, when fully closed, for example, for a pipe with a diameter of 63 mm, the ear is designed so that, when fully closed, the main fitting body has an internal diameter reduced by a maximum of 2%, preferably a maximum of 1%, and preferably a maximum of 0.5%.

[0107] Designing the crimp ring with the correct dimension when fully closed relative to the pipe dimension is a first anti-deformation feature.

[0108] The main connector body 310 is provided with at least one axial slot 361, which allows radial movement of the main connector body 310. During crimping, the main connector body 310 can deform against the pipe and adapt to the shape of the pipe which may have a cross-section that is not perfectly round. The axial slot further prevents deformation of the pipe if the shape of the main connector body does not perfectly match the pipe shape. The axial slots constitute a further anti-deformation element.

[0109] The crimping ring 330 is mounted on the main fitting body 310, on a ring receiving portion 318 of the outer surface 315 of the main fitting body 310. The ring receiving portion 318 is defined by a first radial projection 319A, but, as with the mechanical fitting of [Fig. 2], there is no second projection or a small second projection located at the open end of the main fitting body to hold the crimping ring axially in / on the ring receiving portion 318. In this case, an outer sleeve 340 with a first inward radial projection 341A and a second inward radial projection 341B to hold the crimping ring 330 in place in an axial position prior to crimping.The second inward radial projection 341B is intended to abut the axial outer wall of the open end 311, while the first inward radial projection is intended to abut the axial outer wall of the first radial projection of the main fitting body. The outer sleeve 340 is placed on the crimping ring 330, engaging with the main fitting body, thereby holding the crimping ring on the main fitting body.

[0110] A seal housing 351 for receiving a seal 350 is provided axially between the inner radial projection 312 and the ring receiving portion 318, particularly below at an axial position adjacent the outer radial projection 319A and inwardly from the outer radial projection 319A.

[0111] The rubber housing compresses the rigid pipe and holds against the tearing force, it allows a homogeneous distribution of the crimping load on the pipe, it also compensates for the ovalization of the rigid pipe at zero local pressure. At the same time, the deformed rubber ensures sealing.

[0112] The seal 350 has an internal triangle shape.

[0113] In the examples illustrated in the various figures, the outer radial projection 19A, 219A, 319A is axially spaced from the inner radial projection 12, 212, 312. In other words, not the entire length of pipe inserted into the fitting will be below the crimping ring 30 and the free end of the pipe abutting against the inner radial projection 12 is not provided below the crimping ring. In one aspect, not the entire length of the pipe inserted into the main fitting body is covered by the clamping ring, but not the entire length. This is to account for the fact that the end surface of the pipe may not be straight, for example the user may cut the pipe on site and the cut may be inclined.By leaving some space between the insertion end of the pipe and the crimp ring, it is ensured that the inclined part is not below the crimp ring, which would impair the fitting performance.

[0114] This technology has a significant impact on the replacement of solvent cement fittings for CPVC, PVC and PVC-U pipes.

[0115] Once closed, the gripping rings do not deform the pipe 2. The mechanical connection, taking into account the coefficient of friction and the minimum contact surface required to resist the tearing force, provides a well-defined contact both in terms of dimensions but also so as not to put too much stress on the PVC, c-PVC, PVC-U.

[0116] The advantage of a mechanical crimp connection is that it is easy to connect and the network system becomes operational quickly.

[0117] The foregoing description of preferred embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired by practice of the invention. The embodiment has been selected and described in order to explain the principles of the invention and its practical application to enable one skilled in the art to use the invention in various embodiments suited to the particular use contemplated. The scope of the invention is defined by the claims appended hereto and their equivalents.

Claims

Claims

1. A mechanical coupling for connecting pipes or for attaching a pipe, comprising: a main coupling body (10; 210; 310) extending axially between a body end and an open end (11) defining an insertion space for a pipe, adapted to close onto a pipe, a crimping ring (30) mounted on the main coupling body for tightening the main coupling body onto the pipe, wherein the crimping ring (30) comprises an open ring-shaped ring body (31) connected by a crimping ear (36) projecting radially outwardly from the ring body (31), the crimping ear (36) being deformable to close the crimping ring onto the pipe during the crimping process, wherein the mechanical coupling is provided with an anti-deformation device to prevent deformation of the pipe inserted therein during crimping.

2. A mechanical connection according to claim 1, wherein the connection body comprises at least one axial slot, the anti-deformation device comprising the at least one axial slot.

3. A mechanical coupling according to any preceding claim, wherein the coupling body is provided with a reinforcing element under the ring receiving surface, such as an open metal ring, particularly located between the main coupling body and the pipe when assembled.

4. A mechanical coupling according to any preceding claim, wherein an inner surface of the coupling body has circumferential recesses extending radially within the main coupling body, the inner surface forming a friction surface over a contact length as part of the anti-deformation device.

5. A mechanical coupling according to any preceding claim, wherein an outer sleeve (40) is provided on the compression ring, for axially holding the crimp ring on the main coupling body.

6. A mechanical connection according to any preceding claim, wherein the crimping ring (30) is provided on a ring receiving portion (18) of the main body (10) extending between the open end (11) and an outer radial projection (19A) on an outer body surface (14) of the main body (10).

7. A mechanical connection according to the preceding claim, wherein the main body (10; 210) has an internal radial rib (12) at its body end opposite the free end (11; 211), and wherein the external radial projection (19A) is axially spaced from the internal radial rib (12).

8. A mechanical connection according to the preceding claim, wherein a seal (50) is provided inside a seal housing (51) in the main connection body located axially between the internal radial rib (12) and the ring receiving portion (18).

9. A mechanical coupling according to the preceding claim, wherein the seal (50) has an internal triangle shape for insertion of the pipe, with an insertion surface (56) facing the open end of the coupling, and wherein on the rear side of the seal axially opposite the insertion surface (56), the seal (50) has a rear surface (57) having a step shape.

10. A mechanical connection according to claim 9, wherein the seal is a rubber seal.

11. Mechanical connection according to one of claims 1 to 10, the body being made of polymer or composite.

12. An assembly of a mechanical coupling according to any preceding claim and a pipe, wherein the main coupling body and the pipe have a minimum axial contact length (L) according to the following equation: ÿ ---- ---------------------------- <•$'.' V "k''• xi A-? Where Pd is a pressure and DN a nominal diameter of the pipe, and stress a load exerted on the pipe.

13. An assembly according to claim 12, wherein the crimping ring (30) is provided on a ring receiving portion (18) of the main connector body (10) extending between the open end (11) and an outer radial projection (19A) on an outer body surface (14) of the main body (10), and / or wherein, after

14.

15. closing the crimping ring, the external diameter of the pipe is reduced by a maximum of 0.5%. Method of assembling a fitting according to one of claims 1 to 11 and a pipe, comprising the following steps: insert the pipe into the main fitting body, preferably up to the internal radial rib (12), closing the ear of the crimping ring to press the main fitting body against the pipe, wherein the pipe remaining undeformed after closing the crimping ring (30) with the pipe diameter being reduced by less than 0.5% after crimping. Method according to the preceding claim, wherein, during closing of the crimping ring, the seal (50) deforms against the main fitting body (10) on one side and against the rigid pipe on the other side, in particular a rear surface (57) of the seal having a step shape deforms around the pipe to create the seal.

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