Pipe joints or couplings – End to side or plate – Saddle-type clamp
Reexamination Certificate
2000-09-15
2004-03-23
Bochna, David (Department: 3679)
Pipe joints or couplings
End to side or plate
Saddle-type clamp
C264S268000, C264S275000, C137S318000
Reexamination Certificate
active
06709022
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention concerns a device for connecting at least one branch pipe on a fluid-transporting piping system: the fluid transported may be under pressure, in a liquid state or gaseous.
2. Description of Related Art
The invention concerns more particularly said device for connecting a pipe known as a secondary pipe to a main pipe which comprises a first portion forming a sole able to cover one portion of the rear face of the wall of the main pipe on which it rests and/or is nested.
A resistive element (electrically conductive) can be integrated in this sole and is intended to be connected to a current source so as, via heating of the sole and the main pipe, to provoke welding of the device to this pipe: these connection devices known as electro-weldable devices, are particularly adapted to cases where the main pipe transports a fluid under pressure; if on the other hand the fluid is transported without any pressure (or under low pressure), the connection device can be rendered integral with this pipe by means of a mechanical link, such as a strap.
These devices further comprise a tubular sleeve forming a connection piece for the connection of a secondary pipe, as well as a cylindrical shaft (or second sleeve) in which a perforating member is mounted mobile coaxially to the shaft; the perforating member comprises a lower tubular wall whose free extremity forms a cutter for cutting the wall of the main pipe and whose upper portion is externally threaded so as to co-operate with an internal threaded portion of the shaft. These devices are described in the documents U.S. Pat. No. 4.684.417, FR 2 519 578, EP 736 718 and EP 821 193.
The invention is particularly applicable to said devices whose sole, shaft and sleeve form a single moulded plastic piece.
Other connection devices, complex as regards their structure and implementation, are described for example in the document EP-A-0 726 419.
The object of the present invention is to have a connection device of this type being of simple design produced at a reduced cost and being easy to use, even by unqualified workers and which allows a branch pipe be connected to a fluid-transporting pipe system when the fluid transported is under pressure, that is without interrupting the supply of fluid by this pipe (the main pipe).
BRIEF SUMMARY OF THE INVENTION
Thus, the present invention concerns a device (known) for connecting a branch pipe on a fluid transport pipe system known as a main pipe, said fluid transport pipe system comprising a wall separating the fluid from the outer environment, said connection device comprising a support portion (sole) having a shape complementary to that of the outer surface of the wall of the fluid transport pipe and provided with means to render integral the support portion with this outer surface; a device for perforating the wall of the main pipe comprises a perforating member able to be moved inside a cylindrical shaft integral with the support portion so as to make an opening in the wall of the main pipe, as well as a, connection piece for connecting the branch pipe to a main pipe and able to be placed in communication with the latter after said opening has been made and the perforating member has been freed from said opening.
According to one characteristic of the invention, the connection device comprises a sealing device prohibiting (or limiting) the passage of said fluid between the shaft and the perforating member, one portion of the latter being formed by the internal surface of the shaft and which is in sealing contact with a smooth lower portion of the outer surface of the perforating member.
The sealing device preferably includes a toric flange projecting to the internal surface of the shaft which ensures sealing contact with said smooth portion of said perforating member. This flange, which causes a retraction of the internal cross section of the shaft, is preferably formed of a single piece with the shaft when the latter is moulded.
According to one embodiment variant, the retraction of the internal section of the shaft is obtained by a ring with a circular section (toric joint, possibly movable) in a toric throat provided on the internal surface of the wall of the shaft.
This ring can be moulded on the internal surface of the cylindrical shaft and/or be rendered integral with the shaft by means of welding: it can strictly be constituted by an added toric joint (housed) in the throat of the shaft after the latter has been moulded. However, as the moulding of this throat requires the use of an expansible tool (core), the embodiment is difficult to realise.
According to another aspect and in other terms, the invention consists of offering this connection device in which the support portion (sole), the connection end piece, the shaft receiving the perforator and sealing means between the shaft and the perforator are rendered integral by means of moulding or cast moulded; in addition, the sealing means are shaped in such a way so as to enclose the smooth face of the perforator after introducing the latter into the shaft. To this effect, the passage diameter of the sealing means in its free state is smaller than the diameter of said external smooth face of the perforating member. Preferably, the difference of said diameters is between a range of between 0.3 and 0.9 mm and in particular between 0.4 and 0.8 mm.
The sealing means are preferably constituted by one or two annular flanges in the shape of a torus with an axis approximately merged with the longitudinal axis of the shaft and having an approximately semi-circular section. The annular flange is preferably made of the same material as the material constituting the walls of the shaft obtained by means of moulding in a single operation and the profile of the section of the torus is flattened in its central portion.
To this effect and according to another characteristic, the invention consists of providing an injection mould of a plastic outline of the connection device which comprises a core forming a movable portion of the mould which receives or is used to shape the sealing means. So as to shape during moulding a toric sealing flange projecting to the internal surface of the shaft, the movable core preferably comprises an annular throat with the shape of a torus coaxial with the longitudinal axis of the core having approximately the general shape of a cylinder. This throat extends between one extremity portion of the core used for moulding a connection chamber of the shaft and connection piece, and a central portion of the core used for moulding the shaft.
Alternatively, the core may comprise a cylindrical bearing for example equipped with stops for supporting the toric joint. In this case, this joint is rendered integral with the outline by means of cast-moulding during moulding of the latter. This nevertheless has the drawback of requiring an additional handling since it is necessary to have a joint on the core for each part to be produced and then ensuring after removal from the mould that its position is correct.
In both cases, the central portion of the core for moulding the shaft is preferably threaded externally so as, during moulding, to shape the internal threading of the shaft. In this case, the extraction of the core outside the moulded outline is effected by unscrewing the core with respect to the shaft.
During extraction of the core, the shaped sealing means or integrated with the outline are subjected to deformation: a mainly elastic deformation when the sealing element is a cast-moulded joint or basically plastic when this element is constituted by the flange obtained by moulding and in this latter case, this generally results in a flattening of the central portion of the flange.
The invention is able to provide sufficient sealing in practice between the shaft and the perforator. The invention is able to also avoid any delicate visual inspection of the presence of the joint in the moulded part and generally avoids the presence of additional joints mounted on the perfo
Daumas Didier
Daumas Lionel
Kervern Jean-Philippe
Lapeyre Marc
Bochna David
Innovation Gernerale
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