EP4114646A1

EP4114646A1 - Electro-weldable system with saddle and on-pipe support facility that is multi-diameter with electrofusion pads

Info

Publication number: EP4114646A1
Application number: EP21707741.1A
Authority: EP
Inventors: Jean-Philippe GUIGNARD; Jérôme LALANDE; Vincent Beccavin
Original assignee: Sainte Lizaigne SAS
Current assignee: Sainte Lizaigne SAS
Priority date: 2020-03-02
Filing date: 2021-03-01
Publication date: 2023-01-11
Also published as: IL295849A; FR3107666B1; WO2021175794A1; FR3107666A1

Abstract

The invention relates to a support system (1) for a longitudinally elongate, cylindrical, heat-weldable fluid distribution pipe, the system (1) comprising a longitudinally elongate and transversely rounded heat-weldable plastic saddle (2), an electrofusion pad and a clamping strap (3), the saddle (2) having an upper face with a central boss (21) and a lower face, the electrofusion pad being attached in a housing (5) of the lower face, two lug passages (22) being aligned with the boss (21) along a longitudinal axis between the lugs, the saddle (2) comprising, at the sides, two side flanges (20a, 20b) comprising two side ends (28) for attaching to the strap (3), the lower face being concave towards the bottom and in the form of a cylindrical surface with a given radius. According to the invention, a single saddle is configured to be attached by electrofusion to pipes with nominal diameters between a minimum nominal diameter, DN_min, and a maximum nominal diameter, DN_max, with a DN_max/DN_min ratio of between 1.1 and 3.0 and the flanges (20a, 20b) have a gradient of flexibility from the boss (21) towards the side attachment ends, with maximum flexibility near the side attachment ends and minimum flexibility near the boss (21).

Description

DESCRIPTION

TITLE: Electrofusion system with saddle and support installation on pipe, multi-diameter and electrofusion pads

Technical area

The present invention relates generally to the field of fluid distribution networks and in particular water or town gas. It relates more specifically to an electrofusion saddle system for support on a polyethylene pipe / pipe, in particular in HDPE (high density polyethylene) or PELD (low density polyethylene), from PE50 to PE100, or even in PE-Xa (polyethylene reticle). The system saddle allows its use on several pipe diameters as well as the possible insertion of an electrofusion pad into the saddle in the field when saddle installation is to take place. It has applications in particular in the field of connecting subscribers to a fluid network, the fluid being liquid or gaseous.

Technological background

Saddle systems with tightening straps for support on water pipes are known. In general, the saddles are metallic and intended to be installed and tightened against the pipe with the interposition of a seal on the solid pipes. The pipe is pierced through a nipple or boss of the saddle and through a valve installed on said nipple or boss. Currently, water distribution networks increasingly use plastic pipes, typically HDPE which is a hot-melt material. It has been proposed to use heat-sealed saddle systems on these pipes by means of electrofusion devices.

The following documents are known in the field of electrofusion saddles: EP 1231045 but the clamping means are not detailed, EP 0088703 but the clamping means appear complex to implement, GB 0088703, DE 19935424, JP 2008025704, JP 2002174390, JP 2018105371 in which the saddle has a smaller diameter than the pipe, JP H10185068 using a metal layer.

Due to the standardization of pipes, they have nominal diameters (DN) determined and the difference in diameter between two successive DNs is relatively large. In known systems, up to and including DN 225 mm, a given saddle cannot in practice adapt to a range of several nominal diameters: the saddles are mono-diameter. This results in a large number of different models in order to be able to operate on the different DNs encountered. Inventory management is complex and different quantities must be provided for each model depending on the frequency of use of the corresponding DN.

The present invention provides a saddle system whose particular structure allows it to be adapted to a wide range of pipe sizes.

Disclosure of the invention

First of all, according to the invention, a support system for a fluid distribution pipe, in particular water, is proposed, the longitudinally elongated and cylindrical pipe being made of heat-sealable plastic, the system comprising a saddle of heat-sealable plastic material. , an electrofusion shoe and a tightening strap, the saddle comprising an upper face on which is erected a central boss and a lower face intended to come to rest against the pipe, the saddle being elongated longitudinally and rounded transversely, the shoe electrofusion comprising two terminals connection and being attached to a housing on the underside of the saddle, the two connection thimbles passing through the thickness of the saddle in two thimble passages and opening out to the upper side of the saddle, the two thimble passages and the boss being aligned along a longitudinal inter-pod axis of the saddle, the saddle comprising laterally, on either side of the longitudinal inter-pod axis, two lateral wings, the underside of the saddle being concave downwards and in the form of a cylindrical surface of determined radius, the two wings of the saddle comprising two lateral fixing ends intended to allow attachment to the tightening strap, the tightening of the tightening strap allowing the application of the underside of the saddle with its two wings against the pipe.

According to the invention, the same saddle is configured to be fixed by electrofusion on pipes of nominal diameters between a minimum nominal diameter, DNmin, and a maximum nominal diameter, DNmax, with a DNmax / DNmin ratio between 1, 1 and 3 , 0 without mechanical deterioration or leakage during tightening and after electrofusion, and the wings have a flexibility gradient going from the boss towards the lateral fixing ends, the flexibility being maximum towards the lateral fixing ends and minimum towards the boss.

Other non-limiting and advantageous characteristics of the system according to the invention, taken individually or in any technically possible combination, are as follows:

- the flexibility is measured by a stiffness coefficient, the stiffness coefficient being smaller towards the lateral fixing ends than towards the boss,

- the stiffness coefficient is measured along longitudinal sections of the wing,

- the flexibility gradient is obtained by at least one of the following structures: the presence of a plastic material whose composition varies from the boss towards the lateral fixing ends, the presence of the upper face of the wings, on each lateral side of the longitudinal inter-pod axis, of longitudinal grooves parallel to each other and to the longitudinal inter-pod axis, the thicknesses of material between the bottom of the grooves and the underside of the wings decreasing transversely, from groove to groove, from the boss towards the lateral end of the wing, the material thickness of the wings decreases going from the boss towards the lateral fixing ends, the length of the wings, as measured parallel to the longitudinal inter-pod axis, decreases going from the boss to the lateral fixing ends,

- the plastic material whose composition varies is a plastic material with at least two components, with a homogeneous local mixture of the components and the relative proportions of the components varying from the boss to the lateral fixing ends,

- the plastic material, the composition of which varies is a plastic material with at least two components, said at least two components forming a laminated wing structure, that is to say without mixing of the components, and the relative thicknesses of the stratifications of the components varying from the boss to the lateral fixing ends,

- the material thickness of the wings decreases going from the boss to the lateral fixing ends and the length of the wings, as measured parallel to the inter-pod longitudinal axis, decreases going from the boss to the lateral fixing ends,

- the plastic material of the saddle and the plastic material of the pipe are identical, - the upper face of the wings comprises on each lateral side of the longitudinal inter-pod axis longitudinal grooves parallel to each other and to the longitudinal inter-pod axis,

- the thicknesses of material between the bottom of the furrows and the underside decrease transversely, from furrow to furrow, from the boss towards the lateral end of the wing,

- the grooves are elongated longitudinally on the upper face of the saddle and they are parallel to the main axis of the pipe on which the saddle is intended to be installed,

- grooves are interrupted by the boss,

- grooves interrupted by the boss are lateral to the terminal passages,

- grooves are lateral to the boss,

- grooves are continuous from one longitudinal edge of the saddle to the other,

- grooves are discontinuous from one longitudinal edge of the saddle to the other,

- grooves do not reach the longitudinal edges of the saddle,

- the depth of the grooves increases going from the boss towards the lateral ends of the wings,

- the material thickness between the bottom of the groove and the lower face is constant longitudinally,

- in the case of a saddle with a preinstalled electrofusion shoe, in particular by overmolding, the underside of the saddle is uniformly cylindrical in shape, concave downwards, in order to be able to apply uniformly against the pipe after tightening of the tightening strap,

- in the case of a saddle with a preinstalled electrofusion pad, an extra thickness of material projecting downwards from the underside may be present opposite the preinstalled electrofusion pad, said extra thickness being limited to a few tenths of a mm,

- in the case of a saddle with a non-preinstalled electrofusion pad, the underside of the saddle, outside the housing intended to receive an electrofusion pad which forms a hollow in said lower face, is uniformly cylindrical in shape, concave down,

- the same saddle is configured to be fixed by electrofusion on pipes of nominal diameters between a minimum nominal diameter, DNmin, and a maximum nominal diameter, DNmax, with a DNmax / DNmin ratio between 1, 1 to 2.5,

- the same saddle is configured to be fixed by electrofusion on pipes with nominal diameters between a minimum nominal diameter, DNmin, and a maximum nominal diameter, DNmax, with a DNmax / DNmin ratio preferably between 2 and 2.1,

- the system is configured to allow the application of a clamping force of up to 5 kN without mechanical damage or leakage during clamping and after electrofusion,

- the system is configured to allow the application of a tightening force of at least 5 kN without mechanical damage or leakage during tightening and after electrofusion,

- preferably, the saddle is chosen to respect the relation (D _n - DNmin) / (DNmax

- DNmin) = 0.34 to 0.40, where D _n is the diameter of the underside of the saddle before tightening,

- the saddle is configured so that the material thickness of the saddle wings, excluding furrows, is longitudinally constant, -the saddle is configured so that the material thickness of the fenders, excluding grooves, decreases going from the boss to the lateral ends,

- the lateral end of the wing is a lateral end for fixing the strap which comprises a device for attaching the strap, - the lateral fixing ends of the wings each comprise a device for attaching the tightening strap which forms upwards an extra thickness of material compared to the thickness of the wing,

- the lower face of the saddle concave towards the bottom is in the form of a cylindrical surface of determined radius, - the upper face of the saddle, outside the boss and the two lug passages, has a transverse rounding and is generally convex to the top,

- the bottoms of the adjacent furrows of the saddle are separated from each other by longitudinal elevations parallel to the furrows and ending upwards with ridges, said ridges being carried by the transverse rounding of the upper face, - the ridges of the elevations are flattened,

- the crests of the elevations are rounded,

- the crests of the elevations are angular,

- the elevations, seen in cross section of the saddle, are not symmetrical with respect to the radius defining the cylindrical curvature of the underside of the saddle,

- the elevations, seen in cross section of the saddle, are symmetrical with respect to the radius defining the cylindrical curvature of the underside of the saddle,

- the grooves, seen in cross section of the saddle, are not symmetrical with respect to the radius defining the cylindrical curvature of the underside of the saddle,

- the grooves, seen in cross section of the saddle, are symmetrical with respect to the radius defining the cylindrical curvature of the underside of the saddle,

- the upper face in the circular junction part between the central boss and the upper face comprises at least two semi-circular zones of reduced thickness of the material of the saddle between the upper and lower faces, said two semi-circular zones d 'reduced thickness being arranged towards the two lateral sides of the boss,

- on the upper face of the saddle, each of the two lug passages has an upward thickness of material,

- the upper face along the longitudinal inter-lug axis has an upward elevation of material between the boss and each of the two lug passages,

- the saddle is longer at the level of the longitudinal inter-pod axis than towards the two lateral ends of the two wings,

- the saddle is as long at the level of the longitudinal inter-pod axis as it is towards the two lateral ends of the two wings,

- the saddle is symmetrical with respect to a vertical plane passing through the longitudinal inter-lug axis, - the saddle is generally symmetrical with respect to a transverse vertical plane passing through the center of the boss,

- the bottom of the grooves is rounded,

- the bottom of the furrows is angular,

- the bottom of the grooves is flattened, - the electrofusion pad installed in the housing is flush with the underside of the saddle,

- the electrofusion pad is molded into the saddle,

- the electrofusion pad overmolded in the saddle is embedded in the material of the saddle,

- the electrofusion pad has a square, rectangular or circular shape,

- the tightening strap is metallic,

- the metal tightening strap comprises a stainless steel band comprising a latch at each of its two ends,

- the tightening strap is made of plastic,

- the tightening strap is made of plastic and has notches,

- the plastic tightening strap consists of a strip with notches on the surface,

- the plastic tightening strap consists of a strip having on the surface a series of pulling holes through which a pulling tool for tightening can be inserted,

- the pulling tool is a collet,

- The clamp has two ends which can move away or come closer, one end comprising a claw intended to be inserted into one of the traction holes and the other end comprising a tab with two fingers intended to bear on the lateral wing attachment end with saddle hooking device,

- the tightening strap is left in place once the saddle has been electrowelded onto the pipe,

- the tightening strap is a removable element intended to be removed once the saddle has been electrowelded on the pipe,

- the boss is intended to receive a metal insert internally,

- the system has a saddle with a metal insert in the boss

- the saddle is obtained by molding a plastic material,

- the insert is molded into the boss of the saddle.

The invention also relates to a support installation on a fluid distribution pipe, in particular water or town gas, comprising the system of the invention.

The invention also relates to a saddle clamping assembly made of heat-sealable plastic material of a system according to the invention, the assembly comprising, on the one hand, for use with a saddle, a plastic clamping strap comprising notches. and at least one ball with two locking blades arranged inside the ball, the locking blades having spring tabs and locking fingers and, on the other hand, reusable, a pliers-type tool comprising a plate Toothed drive of the notched tightening strap.

The tightening assembly can be declined according to any structural modality and use of the elements of the system and its tools.

The invention finally relates to a method for installing a support system according to the invention on a fluid distribution pipe, in particular water, of nominal diameter, DN, determined, in which a saddle is chosen which is adaptable to a range of pipe diameters, the DN being included in said range, the surface of the pipe is prepared in the saddle installation area of the system, an electrofusion pad is installed in a seat of the saddle in case said electrofusion pad would not be preinstalled, we place the saddle and its electrofusion pad on the prepared surface of the pipe, we install a strap tightening at the lateral ends of the wings of the saddle and said strap is tightened so that the underside of the saddle rests against the surface of the pipe and the electrofusion pad is electrically supplied. Advantageously, the preparation of the surface of the pipe consists of a surface abrasion and a cleaning of the surface of the pipe.

Brief description of the drawings

[Fig. 1] is a perspective view of the system of the invention with a saddle and its tightening strap both made of plastic and a metal insert in the boss of the saddle,

[Fig. 2] represents a trigonometric modeling diagram of the adaptation of the same saddle to pipes of minimum and maximum nominal diameters of a range,

[Fig. 3] represents a geometric modeling diagram of the adaptation of the same saddle to pipes with minimum and maximum nominal diameters of a range,

[Fig. 4] is a perspective view of a variant of the saddle of the system in figure 1,

[Fig. 5] shows a perspective view of the saddle of the system of figure 1, [Fig. 6] shows a cross-sectional view of the saddle of the system of figure 1,

[Fig. 7] shows a view from below, on the underside side, of the saddle of the system of FIG. 1,

[Fig. 8] show a perspective view of a notched strap on which have been slid two ball joints with internally stainless steel locking strips,

[Fig. 9] is a perspective view of a ball joint making it possible to view its locking strip which is disposed inside the ball joint, in a slot passing through the latter,

[Fig. 10] is a perspective view of a strap tightening tool,

[Fig. 11] shows, in a perspective view and in partial section, the mounting of a ball joint on the notched strap and its locking strip which allows the immobilization of the ball joint along the strap,

[Fig. 12] shows a sectional view of a ball joint being slid along the notched strap, its locking strip retracting when the notches pass through,

[Fig. 13] shows a sectional view of a ball joint blocked along the notched strap, its blocking strip abutting against a notch,

[Fig. 14] represents the blocking blade,

[Fig. 15] shows a sectional view of an improved ball joint allowing to visualize the two locking blades which are arranged inside the ball joint, [Fig. 16] is a sectional view of an improved ball joint sliding along the notched strap, its locking strips retracting as the notches pass through,

[Fig. 17] shows a sectional view of a ball joint blocked along the notched strap, the blocking strips abutting against the notches,

[Fig. 18] shows a perspective view of the system of the invention being tightened a notch strap with an improved ball joint using an improved tool for tightening the strap,

[Fig. 19] shows a partial sectional view of a detail of the system of Figure 18 at a wing end with its improved ball joint and the strap. notches, the improved strap tightening tool being used during a recovery phase when tightening the strap, and

[Fig. 20] shows a partial sectional view of a detail of the system of figure 18 at a wing end with its improved ball joint and the notched strap, the improved strap tightening tool being used during a phase. training when tightening the strap.

Detailed description of an exemplary embodiment The description which will follow with reference to the accompanying drawings, given by way of nonlimiting examples, will make it clear what the invention consists of and how it can be carried out.

In principle, the invention relates to a system of multi-diameter, electro-weldable clamping saddles and straps for HDPE (high density polyethylene) pipes. Each saddle can be fixed by electrofusion on pipes of different diameters thanks to the particular structure of the saddle which can be adapted and applied to pipes of different diameters.

The saddle system is optimized in particular in terms of:

- thickness gradient (ie between the lower and upper faces) of material between the longitudinal inter-lug axis (axis passing through the centers of the boss and the connection lugs for connection to an electrofusion machine) and the ends side wings of the saddle,

- of structure by the presence of grooves on the upper face of the wings,

- of shape thinned in thickness (i.e. between the lower and upper faces) of at least the lateral parts of the connection zone between the boss and the upper face of the saddle.

Unlike known saddles, the electrofusion saddle of the invention can therefore be adapted to a wide range of pipe diameters thanks to its thickness gradient between the longitudinal axis between the thimbles and the two lateral ends of attachment to the strap. for clamping on pipes and the advantageous combination of thickness gradient, average thickness, saddle size, grooves and possible semi-circular areas of reduced material thickness at the bottom of the boss of setting, so as to reconcile flexibility, tensile / flexural strength and heat propagation during electrofusion. The longitudinal inter-lug axis is the axis passing through the centers of the lug passages and the boss which are therefore aligned. The proposed solution makes it possible to provide non-overmolded electrofusion pads in the saddles before use in the field and, also, removable clamping means.

The proposed system is in particular configured to allow the application of a clamping force of up to 5 kN without mechanical damage or leakage during clamping and after electrofusion, and, this, with a saddle which is chosen to respect the relation (D _n - DNmin) / (DNmax - DNmin) = 0.34 to 0.40, where D _n is the diameter of the underside of the saddle before tightening.

The system of the invention makes it possible to avoid possible errors of DN planned for interventions in the field because the saddle can adapt to a wide range of nominal pipe diameters. In addition, the result is a small number of saddle references, which results in savings in terms of weight and space requirements for storage, transport and assembly.

Such a saddle system 1 2 with its tightening strap 3 is shown in FIG. 1. The HDPE saddle 2 centrally comprises a central boss 21 forming an open passage between the upper face and the lower face of the saddle. A metal insert 4 is installed in the boss 21 and includes a screw 40 serving to the rotation blocking of the take-over valve to be mounted therein. The metal insert is typically made of brass. The metal insert is molded into the saddle and the screw is used to install the take-off valve. The saddle 2 further comprises, on either side of the boss 21, two terminal passages 22 intended for connections of an electrofusion pad to an electrofusion machine for supplying the pad. The boss 21 and the lug passages 22 are aligned on a longitudinal inter-lug axis which is parallel to the main axis of the pipe on which the saddle 2 can be installed. The lug passages 22 and the boss 21 correspond to increased thicknesses of material relative to the upper face of the saddle 2. In this example of FIG. 1, no heightening of material is implemented along the length of the saddle. 'Longitudinal axis inter-pods between the terminal passage 22 and the boss 21. On the other hand, Figures 4 and 5, it is implemented an elevation of material along the longitudinal axis inter-pods between the terminal passage 22 and boss 21.

Laterally, on either side of the boss 21 and the terminal passages 22, two wings 20a, 20b extend laterally to two lateral fixing ends each comprising a hooking device 28 for the tightening strap 3. In this example, the tightening strap 3 is made of plastic and is a strap with notches.

The upper face of the saddle comprises at the junction with the boss 21 at least two semi-circular zones 27 of reduced thickness of the material of the saddle between the upper and lower faces. These semi-circular zones 27 of reduced thickness being arranged towards the two lateral sides of the boss and are intended to facilitate the deformation of the saddle when it is clamped on the pipe. These semi-circular zones 27 of reduced thickness are therefore oriented substantially vertically because they are made in the thickness of the saddle. In an alternative embodiment (not shown), these semi-circular zones of reduced thickness are produced in the thickness of the boss and are therefore oriented substantially perpendicular to the vertical at the level of the junction between the sleeve and the saddle, c 'that is to say at the base of the sleeve, side of the upper face of the saddle.

The upper face of the saddle 2 comprises, essentially on the wings 20a, 20b, series of grooves 25 parallel to each other. Between the furrows 25 are ridges 24 of elevations between furrows. It can be noted that in this example, the grooves 25 on the side of the longitudinal inter-lug axis are interrupted by the boss 21. In variants, the grooves 25 do not interfere with the boss 21.

The saddle 2 is generally symmetrical with respect to a vertical sagittal plane carried by the longitudinal inter-pod axis. The saddle 2 is also generally symmetrical with respect to a transverse plane perpendicular to the vertical sagittal plane and passing through the center of the boss 21.

Figure 4 shows alternative embodiments relating in particular to the structure of the boss 21 and the structure of the fastening devices

28 of the lateral fastening ends on the wings 20a, 20b and serving to hook the tightening strap for tightening straps of different types. In addition, in the variant embodiment of FIG. 5, the elevations

29 of material along the longitudinal inter-lug axis between the thicknesses corresponding to the passages of lugs 22 and boss 21, have been arranged.

FIGS. 6 and 7 make it possible in particular to visualize the housing 5 hollowed out in the underside of the saddle 2 and intended to receive an electrofusion pad. The depth of this housing 5 is about 1.2 mm but it is possible to provide a depth between 0.5 mm and 2 mm, or even between 0.8 mm and 1.5 mm or, preferably, between 1 mm and 1.3 mm, in particular depending on the shoe provided. This substantially square-shaped housing has longitudinal appendages for the passage of electrical connections to the terminals. The electrofusion pad comprises an electrical conductor intended to heat because of its ohmic resistance, wound in the form of a spiral coil, flat, in a very small thickness or of another form, for example helical with flush turns.

The optimizations indicated are intended to give the saddle a flexural capacity and in particular its wings by clamping on the pipe, before the electrofusion, while resisting the thermomechanical and hydraulic constraints characteristic of the application once the electrofusion carried out. With this ability, a given saddle can be installed on pipes of a wide range of diameters. This installation with electrofusion is carried out without the appearance of any crack or cracking visible on the saddle and the tearing of the latter from the pipe is impossible except to lead to a destructuring of the pipe and the saddle.

In practice, different references of saddles are provided which are more particularly suited to different ranges of pipe diameters. In general, for the water pipes usually encountered, there are 2 to 4 references of saddles and 1 to 3 models of electrofusion pads. Typically, 2 to 4 saddle references and 1 or 2 pads can be provided for "X" output bosses (see below) and, 2 to 3 saddle references and 1 to 3 pads for "Y" output bosses. .

For example, three saddle references can be provided, a first reference for pipes with DN between 50 and 90, a second reference for DN between 90 and 180, a third reference for DN between 180 and 400, the diameters being in mm and DN being the Nominal Diameter of the pipe / pipe and which corresponds to the outside diameter for plastic pipes.

In general, the multi-diameter support system can be applied to pipes of very different values of nominal diameters, DN, and, typically, between 40 mm and 500 mm, different saddle references applying. at different ranges of DN between these values.

These different references are mainly differentiated by their initial / unconstrained radii of curvature and their dimensions, essentially the dimensions of their side wings which must cover more or less large areas depending on the DN. It will be understood that the longitudinal dimensions may be different depending on the references and, also, more generally, that all the dimensions may be adapted as a function of the diameter of the boss intended for the take-up branch. In fact, two types of exit boss can typically be provided, a first, called “X”, of 40x3 in mm and a second, called “Y”, of 55x3 in mm. Note that in general and preferably, output bosses "Y" 55x3 in mm are provided only for DN greater than or equal to 90 mm.

Exit bosses are also provided with a gas thread for drinking water.

Finally, the size of the electrofusion pad is adapted so that the pad surface is larger for references of saddles having a larger contact surface with the pipes as is the case with high DNs. However, to further optimize the system, one size of pad can be used for “X” saddles and a single, larger size pad for “Y” saddles.

Examples of dimensions will now be described in the exemplary case of three references of electrofusion saddles provided for DN between 40 mm and 400 mm. These saddle dimensions relate to unconstrained saddles. We consider here a saddle which is configured to be tightened on the pipe by means of a notched strap.

The RADIUS of the underside of the saddle is as follows in the following example of a range with 3 "X" saddles and 2 "Y" saddles:

[TABLE 1]

The typical minimum DNs, lower than the preferred minimum DNs, are pipe diameters for which the installation of the saddle must be particularly careful and the result well controlled due to the extreme stresses applied to the saddle and in particular to its wings but also to driving.

For the transverse dimension, DT, of the saddle, between the lateral ends of the two wings, more precisely between the centers of the two opposite housings for receiving the notches of the tightening strap in the case of a notched strap, we consider the dimension along the arc of a circle between the centers of the two opposite slots for the notches of the tightening strap:

[TABLE 2]

Note that the tightening strap can be of another type and in particular a strap with ratchets or latches. For the LENGTH of the saddle, measured along the longitudinal inter-lug axis passing through the two lug passages and the center of the boss, we have the following dimensions given by way of example:

[TABLE 3]

Another characteristic is the reduction in the saddle length laterally, that is to say towards the ends of the fenders, the fenders therefore having wide bases on the boss side and narrow tops next to their lateral ends for attachment to the strap, is another characteristic ( in addition to the reduction in thickness but also to the minimization of the lateral span DT / transverse dimension compared to conventional saddles) making it possible to reduce the quantity of material by moving away from the axis passing through the pods. This provides the flexibility required for multi-diameter plating of the saddle, without deterioration or breakage of the saddle.

The system is all the more adaptable to different nominal diameters as the amount of material of the saddle to be constrained by clamping on the pipe is reduced. This reduction in material can be obtained in several ways, among others: by reducing the thickness of the wings going towards their lateral ends, by reducing the length of the wings going towards their lateral ends, by reducing the length of the saddle between the two lateral ends of the wings (decrease in TD / transverse dimension). These ways of doing things can advantageously be combined and even combined with others such as, for example, the use of grooves. This gives more flexibility / deformability without resorting to excessive tightening forces, while being able to accommodate an electrofusion pad, and without becoming too fragile.

More generally, the adaptability is due to the existence of a flexibility gradient in the wings going from the boss towards the lateral binding ends, the flexibility being maximum towards the lateral binding ends and minimum towards the boss.

The presence of this flexibility gradient can be determined by measurements of the stiffness coefficient. It can be noted that the converse of stiffness is flexibility or suppleness, which is defined by its amplitude, that is to say the deflection, and the force necessary for this deflection movement. We can therefore consider the stiffness as well as the flexibility / suppleness.

In the case of the shape of the saddle and its wings and its use, the stiffness to be considered is angular, in N.m / rad: ke = M / Q where M is the moment of force.

Thus, the more flexible the saddle with its lateral wings, the weaker ke is and therefore the smaller M required is for a target deflection Q or the greater Q is for a given force M.

The energy applied to press a saddle is reflected in its curvature, bringing its side wings closer (towards small diameters of pipes) or away (towards large diameters of pipes). This energy is proportional to the product of displacement R DQ and the tangential component of the force necessary for this displacement. As a simplified example, the saddle can be modeled on the basis of a cylindrical hollow tube of external diameter D and internal diameter d. In such a simplified case, the moment of inertia is p (D ⁴ - d ⁴ ) / 64 and the modulus of inertia is p (D ⁴ - d ⁴ ) / 32 d. Consequently, if the thickness decreases, preferably on the outer side of the wing, D decreases and therefore the moment of force, the modulus and the stiffness decrease. Finally, at a point outside the neutral fiber of a saddle, the stress is proportional to the product of the modulus of the saddle material and the deflection, the risk of rupture being on the extended face (greater for small diameters). , lower towards large diameters). The bending moment is proportional to EI / R where E is the modulus of elasticity of the material, I is the moment of inertia and R is the radius at the effective curvature of the saddle. Thus, if the modulus of the material of the saddle decreases, the maximum stress thus decreases in the same way as if the deflection were reduced.

This flexibility gradient can be obtained in various ways, each sufficient in itself, but which can be combined with each other: by reducing the material thickness of the wings going towards the ends, by reducing the length (i.e. -d. longitudinally) of the wings going towards the ends, by the presence of increasingly deep longitudinal grooves going towards the ends (the thickness of the wings being uniform or decreasing), by a chemical formulation of the plastic material with properties mechanics varying transversely in the saddle. In the latter case, it is possible to use a plastic material with at least two components, one of which is more flexible than the other (or less rigid than the other), the proportions of the two varying laterally, in the wings, the more flexible (or less rigid) being in greater proportion going towards the ends. These two components can be mixed together, the wings being structurally homogeneous, or these two components can remain individualized, the wings being structurally stratified.

The plastic material with several components can thus constitute a material with a composition gradient, also called FGM (“Functional Gradient Materials”). Their simple structure consists of a gradual evolution from one part to another of a piece by a continuous change of composition. Their transition profile is defined in order to obtain the desired function.

Regarding the geometric parameters of the boss, the following dimensions given by way of example can be used:

[TABLE 4]

Concerning the geometric parameters of the end zone of the wings accommodating the notches of the tightening strap, and what are the hollowed out length, the void length, the center / edge distance and the radius for the notches, it is proposed:

[TABLE 5] p.

Concerning the electrofusion pad which is attached / embedded in a housing on the underside of the saddle, its dimensions are adapted in particular as a function of the boss in question. By way of example, we consider a square-shaped pad of side 77x77 mm. In practice, only the winding and the connection to the terminals, with or without a “bridge”, differ. In variants in which the pad is incorporated into the saddle as standard, the pad which may or may not be flat, may be overmolded in the saddle and it may be a pad which may be identical to those usable in the field without prior overmolding.

For "X" bosses of 40x3 in mm, the housing has the following dimensions (the thickness corresponds to the depth of the housing):

TABLE 6]

For 55x3 mm "Y" bosses, the housing has the following dimensions:

TABLE 7]

It is understood that it is possible to produce electrofusion saddles adaptable to DN ranges according to dimensions and number of references other than those presented above. This will be better understood by the following explanations which give more general indications on the methods of selecting and calculating the dimensions of the saddles.

In the trigonometric modeling which follows, figure 2 shows the unconstrained saddles (circular arc in solid line) and constrained (circular arc in dashed line), i.e. tight against pipes PE 100 (polyethylene) at DNmin (ie minimum diameter, diagram on the left of figure 2) and DNmax (maximum diameter, diagram on the right of figure 2), the pipes being represented in the form of circles. In one case, the saddle is tightened against the pipe (its diameter is reduced by the clamping stress) and in the other case it is widened (its diameter is increased by the clamping stress). It is also possible to determine the dimensions of the saddles according to another modelization, this time geometric, in relation to figure 3. This one shows on a single diagram the unconstrained saddle (continuous line arc) and constrained (arcs dotted line) i.e. tight against PE 1 00 pipes at DNmin (ie minimum diameter) and DNmax (maximum diameter), the pipes being circles.

In this modeling, we consider that the end of the saddle to be pressed onto HDPE pipes of different diameters traverses a portion of an ellipse in its deformation range. This portion of ellipse is characterized by a major axis = 2a equal to its internal arc (the one which is required to be placed on pipes of different diameters) and a minor axis 2b = (2 / TT) X 2a and it has a eccentricity e, equal to 0.771 in the present case.

One of the essential characteristics of the saddles of the invention is their minimized lateral extent. Indeed, the arc of ellipse traversed by the lateral ends of the saddle during the deformations between DNmin and DNmax is equal to a times the integral of P _min to P _max of V (1 - (e sin (P)) ² ) dp. There is therefore a relation of proportionality between the arc traveled from DNmin to DNmax and a Db. Or Db = Da '/ 2 and Da' = (B = a = q R _n ) x ((1 / RNmin) - (1 / RN _m ax)): the maximum arc traversable in terms of deformability and mechanical resistance of the saddle is therefore mathematically and physically linked to ((1 / RNmin) - (1 / RNmax)).

To widen the multi-diameter range, ie (1 / RN _ma x - 1 / RNmin) increased, the half-arc a (= B) of the saddle, which is one of the characteristics of their design, can be minimized.

In the case of two examples of saddles, the following values can be obtained: [TABLE 8]

Thus, B72 or B / 2 multiplied by the variation in angle with respect to the native reference angle Q (before deformation of the saddle on a possibly different pipe diameter) constitutes a good estimate of the effective deformation (with a maximum not to be exceeded). From these results, it is possible to select for the examples given a maximum value close to 15 mm for di effective and d2 effective. We can then determine the range and the thickness gradient as well as the arc length of the saddles making it possible to respect the relation (D _n - DNmin) / (DNmax - DNmin) = 0.34 to 0.40, these limits being advantageous, regardless of the safety coefficient applied to avoid breaking the saddle or the tightening strap on extreme DNs. In this description, D _n (which is equal to 2 R _n ) is the “native” diameter, that is to say before possible deformation of the saddle which is the subject of the invention. Considering the values of the ratio (R _n - RNmin) / (RNmax - RNmin), we can take a value, considered optimal, which is 0.363 = 1 - b / a = 1 - 2 / TT.

We can also consider a ratio of the extreme DNs (the min and max) by the following relationship: DNmax = 2.05 DNmin, the coefficient 2.05 being advantageous but can preferably be chosen from 2.0 to 2.1. Optionally, you can choose another coefficient with a value between 1, 1 and 3.0 to maximize the multi-DN applicability of the system. Thus, for example, it is possible to provide a DNmax to DNmin ratio of 1.1 with DNmax = 200 mm and DNmin = 180 mm up to a ratio of 2.5, or even 3, for example from DN 75 to DN 225.

That is :

(Rn - RNmin) / (RNmax RNmin) ⁼ R ⁼ 0.37 RNmax / RNmin = R ”= 2.05 (or less)

Rn / RNmin = 1 + R "((RNmax / RNmin) - 1) = 1 + R" (R "- 1)

= 1, 3885 if R ”= 2.05 (or less: 1, 259 if R” = 1, 7 for example)

Rn / RNmax = (Rn / RNmin) / R ”

Note that the minimums of q, B and B '(ie the geometrical characteristics of the saddle) are imposed by the smallest electrofusion pads which can ensure sufficient adhesion on the PE100 pipes considered, to which must be added a peripheral zone d 'approximately 10 mm as well as the zone corresponding to the hooking device 28 of the lateral end for fixing the strap to the lateral end of the wings 20a, 20b. The fastening device 28 has housings for the notches of the notched tightening strap or any other fastening means for other types of straps, in particular with ratchets or latches.

From the relationships obtained, the following saddle references can be made, by way of example, the values listed being nominal diameters in mm:

For an "X" type exit boss:

^* With R ”= 2.05:

- choice of two references with 2 non-overlapping ranges: 63-125; 140-280,

- choice of three references with 3 non-overlapping ranges: 40-75; 90-180; 200-400,

- choice of three references with 3 overlapping ranges: 50-90; 90-180; 180-355.

^* With R ”= 1, 7:

- choice of three references with 3 non-overlapping ranges: 63-90; 125-180; 200-340,

- choice of three references with 3 overlapping ranges: 63-90; 90-140; 140-250,

- choice of four references with 4 joining ranges: 63-90; 90-140; 140-250; 250-400.

For a “Y” type exit boss:

^* With R ”= 2.05:

- choice of two references with 2 non-overlapping ranges: 90-180; 200- 400,

- choice of two references with 2 joining ranges: 90-180; 180-355. * With R ”= 1.7:

- choice of two references with 2 non-overlapping ranges: 90-140; 160- 280

- choice of three references with 3 non-overlapping ranges: 90-140; 160-280; 315-500

- choice of three references with 3 joining ranges: 90-140; 140-225; 225- 355

Concerning the characteristic of reduction of the material thickness towards the lateral ends of the wings of the saddle, it can be expressed by a percentage of reduction in thickness per mm of arc compared to the thickness present towards the axis longitudinal inter-pods (excluding elevations and extra thicknesses due to thimble passages and bosses).

This reduction in thickness can for example correspond to a thickness of the wing on the boss side of 7.5 mm before the first groove and decreasing to a wing thickness of 4.5 mm after the last groove, on the side end side. of the wing. More generally, the wings, on the boss side and outside a groove, may have thicknesses between 6 mm and 9 mm and on the lateral end side and outside a groove, have thicknesses between 3 mm and 6 mm. The difference in height of the wing between the side of the boss and the lateral end and outside the grooves and the rigging device can be between 2 and 6 mm. It is also possible to implement saddles without a thickness gradient on the wing, i.e. there is no difference in wing height between the side of the boss and the wing. 'lateral end and outside the grooves and the hooking device. Thus, the saddle may have wings of constant thickness, for example between 8 to 9 mm. These heights outside the grooves are measured at the highest point and outside the boss itself or the semi-circular zones of reduced thickness bordering the boss or the elevations or extra thicknesses of the longitudinal axis between the thimbles or of the attachment device 28 strap 3 at the lateral end of the wing 20a, 20b.

Note that this reduction in thickness between the lower face and the upper face of the saddle towards the lateral ends of the wings may preferably only concern the bottom of the grooves. Thus, for example, provision is made for a constant thickness of the wings of 8.5 mm at the level of the ridges between the grooves and a height of material at the bottom of the groove (height of material defined by the shortest distance between the lower face and the groove bottom) ranging from 7.5 mm (towards the boss) to 5.4 mm (towards the ends of the wings) in the case of five grooves per side wing for a half-arch saddle B = 70.5 mm.

More generally, the depth of the grooves can be between 0.5 mm and 4 mm. The number of grooves may be between 3 and 11 per wing and is preferably between five and seven. Preferably, the depth of a groove is constant longitudinally but in alternative embodiments it may be different in length and, in particular decrease towards the longitudinal ends of the groove or even the groove does not go to the longitudinal edges of the wing. Thus, the grooves are preferably extended longitudinally from one longitudinal edge to the other of each wing and they are therefore lateral to the boss. However, lateral grooves can be provided at the lug passages which are interrupted by the boss because they are close to the longitudinal inter lug axis.

Preferably, the grooves are arranged regularly angularly, for example every 5.5 ° along the wing. Preferably, the two lateral sides of each groove are two flat faces and the bottom of the groove is rounded with a small radius of about 0.5 mm in order to limit the risks of starting notches at the bottom of the grooves.

It is ensured that the shape of the grooves and of their lateral sides allow easy demolding of the saddle during its manufacture following an injection of HDPE into a saddle mold. For this, it is possible to ensure that the faces closest to the vertical of the lateral sides of the grooves are oriented towards the center of the saddle, which can be obtained for example with an opening of 98 ° applied to all the grooves.

The wings therefore have a quantity of material which decreases going towards their lateral ends for attachment to the strap and, this, in two ways: on the one hand, by reducing the thickness / height of material between the lower face and the upper face of the saddle going towards the lateral ends of the wings and, on the other hand, by reducing the length (measured parallel to the longitudinal inter-pod axis) of the wings going towards the lateral ends of the wings.

It is understood that the indications given can serve as a method for determining the dimensions of the saddles adaptable to different DN of pipes. It is thus possible to determine other numbers of saddle references for the pipe DNs encountered. Thus, instead of the three references in the example given above and for HDPE pipes for drinking water, typically 63 mm or even 50 mm up to 315 mm or even 400 mm, a number of references limited to:

- 2 to 4 types of saddles and 1 to 2 electrofusion shoe (s) for "X" 40x3 output bosses in mm, which can make up to 8 references;

- 2 to 3 types of saddles and 1 to 3 electrofusion pad (s) for 55x3 "Y" output bosses in mm, which can make up to 9 references.

In addition, since the electrofusion pad is crossed at its center by a through hole corresponding to the through hole of the boss, the pad is preferably adapted to the dimensions of the boss.

Until now we have considered a support on a water pipe but it is understood that the support system of the invention can be applied to fluids other than water and, for example, for gas.

For inserts, the following dimensions can eg. be used:

[TABLE 9]

It is also possible to provide support systems for bosses suitable for G 3/4 ”, 1”, TΊ / 4 and 1 ”1/2 gas pitch outputs. In this case, the ranges to be covered can be distributed according to the number of references given in the following table:

[TABLE 10]

Different types of grooves and any sealing lips can be implemented on or in the central channel of the brass insert to ensure that a valve is screwed on without leaks once the system is in service. In addition, in order to improve the mechanical adhesion to the interfaces and the sealing, the presence of crenellations or relief on the faces of the brass insert can be taken advantage of, as can the addition of orifices made to be filled with polyethylene during the injection step.

It can be noted in the section of Figure 6 of a saddle intended to receive a metal insert, that a circular groove 26 sinking into the boss is provided around the internal passage channel of the nipple. This circular groove is intended to receive a circular crown projecting downwards from the metal insert. In a variant, a metal ring independent of an insert is installed, preferably overmolded, in said circular groove 26.

Regarding electrofusion pads, the saddles can be delivered with the overmolded pads, therefore pre-installed, or with pads to be fitted into the saddle by the installer, when installing the saddle, just before electrofusion. In the latter case, the electrofusion saddles and pads thus available in the form of separate / separate supplies can in particular avoid errors in the range of pipe or outlet diameter (40 or 55 mm) on which the connection is provided. Electrofusion pads are generally 1.1 mm thick and the depth of the housing is planned accordingly.

The integration of the electrofusion pads by overmolding during the manufacture of the saddles by injection of PE (preferably HDPE) in a mold initially ensures the strength and the tightness between the back of the pads (face of the pad which will not be at the bottom. contact with the PE (HD) pipe and the inside of the saddle housings. electrofusion which ensures the holding and sealing between the back of the pads and the interior of the seat housing.

The installation of a saddle system according to the invention for support on a pipe, eg. a PE100 DN125 pipe, begins by scraping the surface of the pipe using the hand tool to remove the oxide layer usually present. This driving surface is then cleaned with alcohol.

Then, if the electrofusion pad is not preinstalled, an electrofusion pad is positioned on the pipe and the saddle so that the pad is in its housing and the two connection terminals of the pad pass through the two terminal passages. saddle. A tightening strap arranged between the two lateral ends of the wings and allowing the system to encircle the pipe is then tightened in order to force the saddle with its electrofusion pad to be applied by its entire underside on the surface of the pipe. .

The tightening strap may be a strap with latches. The straps are plastics material strips, for example HDPE, PP, NYLON ^®, or metal or woven or a combination of the foregoing. The tightening straps have a suitable width and, for example 50 mm for type "X" saddles. The length of the strap is adapted to the range of diameters provided for the various saddle references. It is possible to provide for cutting an excess length of strap once it is tight.

Figures 8 to 13 show an example of a notched tightening strap 3 and its ball joints 32, usable with the saddles of the invention as well as a tightening tool 39.

In Figure 8, the strap 3 is made of flexible plastic so that it can be wrapped around the pipe. The strap 3 has three main zones over its width, a central zone comprising orifices, in particular for traction, circular 31, and laterally two lateral zones of notches 30. The zones of notches 30 are here discontinuous along the strap 3 but in variants the zones can be continuous. In fact, the discontinuities in the lateral notch zones 30 allow a keying as regards the choice of the saddle reference with regard to the nominal diameter of the pipe on which it is to be installed. The notch zones 30 are arranged so as to allow tightening and blocking of the strap if the correct saddle reference is used for the pipe on which said saddle is installed.

Typically, the notched strap 3 shown can be used for pipes with DN between 90 mm and 180 mm.

The ball joint 32, which resembles a roller, is substantially cylindrical just like the seat or cradle intended to receive it in the attachment device 28.

Two plastic ball joints 32 were slid / slid along the strap 3 in Figure 8. These ball joints will hook into the suitable hooking devices 28 which are at the two lateral ends of the wings 20a,

20b of the saddle 2. The ball has a through slot 37 allowing the insertion of the strap and sliding on the strap.

The ball 32 has internally, in the through slot 37, a locking strip 33 of stainless steel visible in the ball in Figure 9 and whose relationships with the notches are visible Figures 11 to 13. This locking strip 33, Figure 14 , comprises two lateral locking fingers 35 intended to interfere with the notches 30 of the strap 3 and, in the middle position, a spring tab 34 which is inclined by approximately 30 ° relative to the general plane of the locking strip 33, in the absence of stress exerted on the locking strip 33. The spring tab 34 bears against the material of the ball joint and it is therefore not inclined towards the inside of the through slot 37 but on the opposite side. The spring tab 34 allows the locking blade to take two main positions in the ball, a retracted position when the spring tab is constrained and allowing the sliding of the ball 32 along the strap in a tightening direction and a non-position. retracted blocking the ball 32 along the strap in a direction of loosening. Thus, the sliding of the ball joints can only take place in a tightening direction corresponding to bringing the two ball joints together along the strap. The locking strip 33 makes it possible to form a non-return pawl within the ball joint.

In FIG. 11, one can better see the relationships between the notched strap 3 30, the ball 32 and its internal lamella, a lateral locking finger of which has been made visible. One can provide on the surface of the ball, as shown in Figure 11, a depression 36 intended to receive the end of a flat-head screwdriver which can be used to tilt a tight ball on a saddle in order to release it from the notches of the strap and loosen and remove the strap if desired.

The notched strap tightening system is centrable and can be reused if necessary. The tightening system is ergonomic because it requires moderate efforts and can be tightened with a non-disproportionate tightening tool, in particular the pliers 39 in figure 10. Instead of the tool, a rod or a screwdriver can be used and pry up against part of the saddle to pull up the strap.

The clamp 39 of FIG. 10 has two ends which can move apart or come closer, one of the ends comprising a claw 38 intended to be inserted into one of the traction holes 31 and the other end comprising a tab with two fingers intended to be supported on the lateral attachment end of the wing to the saddle attachment device.

It can be noted in FIG. 8, along the central zone comprising the traction orifices 31 which are circular, the presence of an elongated opening 31 'and it corresponds to a zone where there can be no fixing by the ball joints 32 More generally, the ball joints can only be retained along the strap and allow stable tightening of the saddle in the areas where the notches are present.

Once the saddle 2 is installed on the pipe and the strap 3 tightened so that the side wings 20a, 20b apply to the surface of the pipe, the electrofusion is implemented. After the electrofusion, the assembly is allowed to cool for at least 30 min and then, if desired, the tightening strap can be removed if it is removable, such as a strap with latches or the strap. with notches with its ball joints that can be tilted thanks to the depression 36.

When drilling the pipe for support, the connection equipment with the drilling tool is installed on the boss of the saddle. It may be preferable that the tightening strap is left in place during the piercing operation and removed only afterwards if the strap is to be removed.

We will now present an improved version of the system in which the means for clamping the saddle on the pipe are improved.

In FIG. 15, an improved ball 32 with two locking blades 33 arranged inside the ball is shown in section. The two locking strips 33 with spring tabs 34 and lateral locking fingers 35, have a Similar operation to the lamella of the single leaf patella shown above. With this improved ball joint, the maintenance and tightening of the strap 3 are improved both dynamically, during installation, and statically, after installation and tightening. It can be seen in the figures, during sliding (Figure 16), the passage of the notches through the locking fingers 35, and after final tightening, the locking fingers 35 locked in the notches (Figure 17). The use of two locking strips 33 makes it possible to better distribute the clamping stresses and reduces the risks of sliding and loosening between notches and locking fingers. An improved clamp 39 is implemented in Figure 18. Figures 19 and 20 make it possible to better visualize the structure of this improved clamp 39 which comprises a toothed plate 41 for driving the notched strap 3. In FIG. 20, the superimposed teeth of the toothed plate 41 drive the notches of the strap 3 to pull the strap upwards, during the tightening of the handles of the improved collet 39, clamping which drives the toothed plate upwards. 41. Thus, the improved clamp 39 is placed from above the wing end of the saddle to allow tensioning of the strap and the saddle on the pipe by pulling and tightening the strap. .

In FIG. 19, the improved clamp 39 is brought back to a state where it can subsequently pull the strap again, the toothed plate 41 being lowered, its teeth slipping on the notches of the strap 3. The improved ball joint 32 with its two locking strips 33 and the notched strap 3 operate in the manner of a ratchet.

Claims

1. Support system (1) for a fluid distribution pipe, the longitudinally elongated and cylindrical pipe being made of heat-sealable plastic, the system (1) comprising a saddle (2) of heat-sealable plastic, an electrofusion pad and a tightening strap (3), the saddle (2) comprising an upper face on which is erected a central boss (21) and a lower face intended to come to rest against the pipe, the saddle (2) being elongated longitudinally and rounded transversely, the electrofusion shoe comprising two connection lugs and being fitted into a housing (5) of the underside of the saddle (2), the two connection lugs passing through the thickness of the saddle in two passageways thimble (22) and emerging at the upper face of the saddle (2), the two thimble passages (22) and the boss (21) being aligned along a longitudinal inter-lug axis of the saddle (2), the saddle (2) comprising laterally, on either side of the longitudinal inter-pod axis, two lateral wings (20a, 20b), the underside of the saddle being concave downwards and in the form of a cylindrical surface of determined radius, the two wings (20a , 20b) of the saddle (2) comprising two lateral fixing ends (28) intended to allow fixing to the tightening strap (3), the tightening of the tightening strap (3) allowing the application of the underside of the saddle (2) with its two wings (20a, 20b) against the pipe, in which: the same saddle (2) is configured to be fixed by electrofusion on pipes of nominal diameters between a minimum nominal diameter, DNmin, and a maximum nominal diameter, DNmax, with a DNmax / DNmin ratio of between 1, 1 and 3.0 without mechanical deterioration or leakage during tightening and after electrofusion, and in which the wings (20a, 20b) have a flexibility gradient in going from the boss (21) to the lateral binding ends, the flex ibility being maximum towards the lateral fixing ends and minimum towards the boss (21).

2. System (1) according to claim 1, wherein the flexibility gradient is obtained by at least one of the following structures:

- the presence of a plastic material whose composition varies from the boss (21) to the lateral fixing ends,

- the presence on the upper face of the wings (20a, 20b), on each lateral side of the longitudinal inter-pod axis, of longitudinal grooves (25) parallel to each other and to the longitudinal inter-pod axis, the thicknesses of material between the bottom of the grooves (25) and the underside of the wings decreasing transversely, from groove to groove, from the boss (21) towards the lateral end of the wing (20a, 20b),

- the material thickness of the wings (20a, 20b) decreases going from the boss (21) to the lateral fixing ends,

- the length of the wings, as measured parallel to the longitudinal inter-pod axis, decreases going from the boss (21) to the lateral fixing ends.

3. System (1) according to claim 2, wherein the material thickness of the wings (20a, 20b) decreases going from the boss (21) towards the lateral fixing ends and the length of the wings, as measured parallel to the longitudinal inter-pod axis decreases going from the boss (21) to the lateral fixing ends.

4. System (1) according to any one of claims 1 to 3, wherein the system is configured to allow the application of a clamping force of up to 5 kN without mechanical damage or leakage during clamping and after electrofusion. , and in that the saddle is chosen to respect the relation (D _n - DNmin) / (DNmax - DNmin) = 0.34 to 0.40, where D _n is the diameter of the lower face of the saddle before tightening.

5. System (1) according to any one of claims 1 to 4, wherein the upper face of the wings (20a, 20b) comprises, on each lateral side of the longitudinal inter-pod axis, longitudinal grooves (25) parallel to each other and to the inter-pod longitudinal axis.

6. System (1) according to claim 5, wherein the thicknesses of material between the bottom of the grooves (25) and the underside decrease transversely, from groove to groove, from the boss (21) towards the lateral end. wing (20a, 20b).

7. System (1) according to any one of claims 5 and 6, wherein the bottom of the grooves (25) is rounded.

8. System (1) according to any one of claims 1 to 7, wherein the upper face in the circular junction part between the boss (21) central and the upper face comprises at least two semi-circular areas (27). of reduced thickness of the material of the saddle (2) between the upper and lower faces, said two semi-circular zones (27) of reduced thickness being disposed towards the two lateral sides of the boss (21).

9. System (1) according to any one of claims 1 to 8, wherein the electrofusion pad is molded into the saddle (2).

10. System (1) according to any one of claims 1 to 9, wherein the tightening strap (3) is a removable element intended to be removed once the saddle (2) is electrowelded on the pipe.

11. System (1) according to any one of claims 1 to 10, wherein the tightening strap (3) is made of plastic and comprises notches (30).

12. System (1) according to any one of claims 1 to 11, wherein, at the upper face of the saddle (2), each of the two lug passages (22) comprises an upward thickness of material and in that the upper face along the longitudinal inter-lug axis comprises an upward elevation of material between the boss (21) and each of the two lug passages (22).

13. Support installation on a fluid distribution pipe, in particular water, comprising the system (1) of any one of claims 1 to 12, electro-welded to said pipe.

14. Saddle clamping assembly in heat-sealable plastic material of a system (1) of any one of claims 1 to 12, the assembly comprising, on the one hand, for use with a saddle, a clamping strap ( 3) made of plastic material comprising notches (30) and at least one ball (32) with two locking strips (33) arranged inside the ball (32), the locking strips (33) having spring tabs (34) ) and locking fingers (35) and, on the other hand, reusable, a pliers-type tool (39) comprising a toothed plate (41) for driving the notched tightening strap (3).