FR2716250A1 - Automatic security device for gas installations - Google Patents

Abstract

The security device connects between the connection on a pipe and a part of a pipe such as a tap. The device comprises two elements (1,2) which are adapted to be fixed so that they cannot be taken apart. The two elements are automatically bolted together one to the other. The first element (1) is mounted on the pipe or part of the pipe and the second element (2) is at least partially put on the first element. The first element includes retaining mouldings or teeth (3) which are elastically deformable during the fixing of the two elements, and are locked in place by complementary interior depressions (5) in the second element.

Description

AUTOMATIC SECURITY DEVICE FOR
INDUSTRIAL OR DOMESTIC GAS INSTALLATIONS
The invention relates to an automatic safety device for industrial or domestic gas installations.

 Document FR 2 689 607 describes an automatic safety device comprising a body capable of being made inseparable from a gas pipe made of rigid material.

The body has a housing for a shutter assembly provided with a retaining means in the open position so as to move in the direction of gas flow if a predetermined value of the gas flow is exceeded, to be kept in the closed position on a seat secured to the body and be returned to the open position by said retaining means in the absence of relative gas pressure.

 This device is generally satisfactory, but requires the use of a ring of elastomeric material such as nitrile intended to be crushed by a nut in two parts secured by a shear pin, or alternatively requires intervention on the pipe or a member integral with the latter by welding, brazing or machining an additional thread.

 The object of the invention is to remedy these drawbacks by proposing a new device, the installation of which does not require the above-mentioned intervention on a pipe or a member secured to a gas pipe.

 The invention relates to an automatic safety device for industrial or domestic gas installations, having a general conformation of connection to a pipe or to a pipe member such as a tap, and comprising a housing for a shutter assembly constituted by a retaining means and a movable valve assembly; said shutter assembly being able to move in the closed position in the direction of gas flow in the event of a predetermined value of the gas flow rate being exceeded and to be recalled to the open position in the absence of a determined gas pressure, characterized in that the device comprises two elements capable of being secured in a non-removable and self-locking manner to each other, the first element being mounted on the pipeline or the channeling member and the second element at least partially covering the first element .

According to other features of the invention
- The first element includes reliefs, teeth or elastically deformable retaining lugs when the two elements are joined and locking by elastic return in an internal conformation of the second element
- the second element is mounted to rotate freely on the first element
- The first element comprises a separable member after obtaining a force or a predetermined assembly torque with the pipe
- the first element is assembled to the pipe or to the pipe member by actuation of a separable nut to compress a seal, then separate the nut before styling the first element using the second element
- the valve assembly has a substantially toroidal support and sealing configuration
- said toroidal conformation is in relief relative to an annular groove
- the cylinder internally limiting said annular groove comprises means for guiding the valve assembly in the downstream passage of the second element
- the guide means have a mechanical structure corresponding to that of a tail unit
- The guide means comprise at least three fins arranged symmetrically with respect to a central axis of symmetry.

The invention will be better understood from the description which follows given by way of nonlimiting example with reference to the accompanying drawings in which
Figure 1 schematically shows in section a device according to the invention, according to an assembly of two half-views in axial section joined together, representing the device according to the invention in two different positions.

 FIG. 2 schematically represents a shutter valve of a device according to the invention, according to an assembly of two contiguous half-views, with a schematic half-view in axial section.

 Referring to Figure 1, a device according to the invention is shown in the open position and before self-locking mounting in the upper half-view A and in the safety position after self-locking in the lower half-view B.

 The device presents externally a general conformation of fitting adapted to be mounted on a gas pipeline while respecting the direction of passage and circulation of the gas identified by the arrow P. For this purpose, the device comprises a first element 1 adapter made of material resilient such as a technical plastic, a metal or a metal alloy and a second element 2 made of metal or a metal alloy capable of covering the first element 1 and of being retained by the latter.

 To this end, the first element 1 comprises a plurality of reliefs 3 or elastically deformable retaining teeth by the action of the cap 4 of the second element 2 and retaining the cap 4 by locking by elastic return in the groove 5 of the cap 4.

 Due to the bracing of the retaining teeth 3 in the groove 5, the mechanical assembly carrying out the joining of the elements 1 and 2 is self-locking and non-removable without at least partial destruction of an element 1 or 2.

 To carry out this mechanical mounting, the first element 1 is fixed to the pipe or to the pipe element such as a tap R, for example, a tap with a threaded connection end 6; the invention obviously applies to any type of end piece that can be functionally substituted for a thread cooperating with a thread, such as an end flange, a self-locking ball or elastic ring connection device cooperating with a housing or a retaining groove the essential is according to the invention that the first element 1 comprises a removable connection means to a pipe or to a pipe member R, a sealing means such as an O-ring 7 being provided to ensure the sealing at the junction between the pipe or the pipe member R and the first element 1.

 In the example shown, the first element 1 comprises a nut 8 by which the first element 1 is screwed onto the threaded end 6 of the valve R by compressing the O-ring 7 permanently mounted and trapped on the first element 1 against a face of support of the end of the tap R. When obtaining a predetermined assembly torque corresponding to the rupture of ribs 9 connecting the nut 8 to the main body of the first element 1, the nut 8 separates from the body of the first element 1 so that it is no longer possible to dismantle, using conventional tools, the first element 1 of the threaded end 6 of the valve R.

 The rupture of the ribs 9 and the separation of the nut 8 which has an outside diameter greater than the inside diameter of the second element 2 allows the passage of the second element 2 around the first element 1 to cover the latter and lock the elements 1 and 2. one to the other due to the cooperation of the retaining teeth 3 and the groove 4. A seal 10 is provided to seal at the interface between the two elements 1 and 2: this seal sealing 10 is preferably an O-ring 10 permanently mounted in a groove 11 of the first element 1.

 Thanks to the invention, the element 2 covering the element 1 and self-locked in a leaktight manner is mounted to rotate freely: this arrangement is advantageous and avoids any transmission of torque through the device according to the invention . In particular, in the case where a pipe of the flexible tube type with mechanical connection ends is connected to the end 12 of the second element 2, unwanted twisting of the flexible tube and its premature damage are avoided. In this particular case, provision is made to provide in the vicinity of the threaded end 12 at least one clamping plate 13 or 14, and preferably two clamping plates 13 and 14, corresponding to the holding and immobilization of the second rotation. element 2 using an open-end wrench or similar key.

 In the passage 15 of the element 2 located downstream in the direction of flow P of the gas, guide fins 16 are slidably engaged to guide the movement of a shutter assembly 17 comprising a movable valve described below with reference in Figure 2 and a retaining means 18 of known type, described and shown in document FR 2 689 607, the content of which is considered to be incorporated in the present description.

 The retaining means 18 is fixed to the first element 2 by cooperation of its fixing ring 18a engaged in a groove 19a formed at one end of a recess 19 of diameter greater than the nominal diameter of the passage 15.

 The operation of the device is described in the document FR 2 689 607: above a predetermined value of incoming gas flow, the shutter assembly moves from position A to position B in the direction of flow P of the gas. until the valve rests on its seat and is held in position by the force exerted by the relative pressure of the gas on the external surface of the shutter valve.

 Referring to Figure 2, a valve assembly adapted to be mounted on a retaining means of the type described in document FR 2 689 607 comprises in known manner a substantially cylindrical upper part 20 of diameter corresponding to that of the ring fixing of the retaining means, an enlarged part 21 which is substantially conical and elastically deformable, a cylindrical fixing rod 22 on which the ring of the retaining means is mounted, a flange 23 constituting a stop for said ring to which a surface 24 having an aerodynamically shaped profile adapted to the flow of gas.

 According to 1 invention, the valve assembly has a substantially toroidal support and sealing configuration 25 in relief in relation to an annular groove 26, and the internally hollowed assembly comprises at least three guide fins arranged symmetrically with respect to the axis CC of symmetry of the valve assembly and inside the geometrical cylinder radially limiting internally the annular groove 26.

 In the example shown comprising three fins, these three fins 16 are arranged at 1200 from one another around the axis C-C. Each fin 16 has a cylindrical contour 27 radiated so that, when guiding the valve assembly in the corresponding passage, the possible contact between this passage 15 and the fin 16 is established substantially along a generatrix, notably reducing the friction between the fin 16 and this passage 15. To avoid any effect of end bracing during guidance, provision is made to make a cut or chamfer 28 at the end of each fin 16 at an angle A of the order of 30 relative to the direction of the axis of symmetry CC.

 Preferably, in order to facilitate manufacture and to lighten the valve assembly, provision is made to reduce the non-functional surface of the fins 16 by practicing a second cutaway radially internally 29.

 The set of fins 16 joining along the axis CC of symmetry then has a mechanical structure similar to that of a jib empennage, that is to say having good central rigidity and flexibility at the ends 28 favoring guiding and the sliding of the valve assembly 15 inside the corresponding passage.

 The recessed valve assembly and of reduced mass is preferably made in one piece, by molding or a similar process providing a continuity of material between the above elements 20 to 29 of a material of the nitrile rubber, elastomer or material type. analog plastic.

 The invention, although described with reference to particular embodiments, is in no way limited thereto, but on the contrary covers any modification of form and any variant embodiment within the scope and spirit of the invention.

 For example, the invention would also apply to the case where the thread 12 is replaced by a self-locking connection device with ball, elastic ring, wire or the like; and in case the thread 12 is adjacent to such a self-locking connection device.

Claims (10)

 1. Automatic safety device for industrial or domestic gas installations, having a general conformation of connection to a pipeline or to a pipeline member such as a tap, and comprising a housing for a shutter assembly constituted by a retaining means and a movable valve assembly; said shutter assembly being able to move in the closed position in the direction of gas flow in the event of a predetermined value of the gas flow rate being exceeded and to be recalled to the open position in the absence of a determined gas pressure, characterized in that the device comprises two elements (1, 2) capable of being secured in a non-removable and self-locking manner to each other, the first element (1) being mounted on the pipeline or the channeling member and the second element (2) at least partially covering the first element (1).  2. Device according to claim 1, characterized in that the first element (1) comprises reliefs, teeth or retaining lugs (3) elastically deformable during the joining of the two elements (1, 2) and locking by elastic return in an internal conformation (5) of the second element (2).  3. Device according to claim 1 or claim 2, characterized in that the second element (2) is mounted to rotate freely on the first element (1).  4. Device according to one of the preceding claims, characterized in that the first element (1) comprises a separable member (8) after obtaining a force or a predetermined assembly torque with the pipe.  5. Device according to one of the preceding claims, characterized in that the first element (1) is assembled to the pipe or to the member (R) of pipe by actuation of a nut (8) separable to compress a joint seal (7), then separate the nut (8) before covering the first element (1) using the second element (2)  6. Device according to any one of claims 1 to 5, characterized in that the valve assembly has a support and sealing conformation (25) substantially toroidal.  7. Device according to claim 6, characterized in that said toroidal conformation (25) is in relief relative to an annular groove (26).  8. Device according to claim 7, characterized in that the cylinder internally limiting said annular groove (26) comprises guide means (16) of the valve assembly in the passage (15) downstream of the second element (2).  9. Device according to claim 8, characterized in that the guide means (16) have a mechanical structure corresponding to that of a tail.  10. Device according to one of claims 8 or 9, characterized in that the guide means (16) comprise at least three fins arranged symmetrically with respect to a central axis (C-C) of symmetry.