FR2714137A1 - Automatic check valve incorporated in gas tap for domestic or industrial installations - Google Patents

Abstract

The automatic check valve is incorporated in a rotary on/off tap in which the rotary plug (1) contains in its through passage (10) a shut off unit (13) which is fixed to the plug (1). It is in the form of a plunger (15) held in position by a retainer (14) which closes onto a seat in the passageway of the plug. This plunger operates to close off the flow through the tap when it exceeds a certain pre-determined value. An orifice (20) is drilled in the side of the plug upstream of the shut off unit (13) to relieve the pressure and reset the plunger (15) when the tap is turned off.

Description

AUTOMATIC SECURITY DEVICE
SHAPING TAP
The invention relates to an automatic safety device forming a shut-off valve, in particular for industrial or domestic gas installations.

 The document FR 2 689 607 describes an automatic safety device for industrial or domestic gas installations which comprises 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. Said shutter assembly moves in the direction of flow of the gas in the event of a predetermined value of the gas flow rate being exceeded, is kept in the closed position on a seat secured to the body by the force exerted by the relative pressure of the gas, and is returned to the open position by said retaining means in the absence of relative gas pressure. The retaining means is made at least partially of a material having a high elasticity, of the elastomer type or the like; the retaining means comprises a substantially toroidal ring carrying three arms joined together by a fixing ring. The three arms have a substantially constant cross section and a substantially spherical curvature profile.

This automatic safety device gives satisfaction when its axis of work and movement is aligned with the axis of the pipeline from which it is made inseparable: this geometric arrangement allows in particular the return to the open position or "resetting" after cutting the gas supply to the pipeline by means of shut-off valves.

 Gas supply shut-off valves are known, in particular taps with conical turning or ball valves. Such shut-off valves, with threaded inlet and outlet, with quarter-turn actuation, are described in the French standards AFNOR (ASSOCIATION FRANCAISE DE NORMALISATION) for example under the standards referenced NF E 29-135, NF E 29- 124 or NF E 29127.

 Consequently, up to now, the installation of an automatic safety device of the type described in document FR 2,689,607 has also required the installation of a stop valve allowing the automatic safety device to be reset.

 The object of the invention is to simplify the provisions of the prior art, by creating a new device simultaneously ensuring automatic safety in the event of an overflow, the interruption of the supply and the automatic or instantaneous reset of the automatic safety after power cut.

 The subject of the invention is an automatic safety device forming a shut-off valve, of the type having a general conformation as a shut-off shut-off valve, characterized in that the turn receives directly a shutter assembly, which is secured to it so as to interrupt the gas circulation on exceeding a predetermined flow rate and so as to reset automatically when the rotary valve closes.

According to other features of the invention
- the turn has a passage, in which is formed an annular groove with a diameter greater than that of the passage
- The passage also has a recess corresponding to the movement of a retaining means of a movable valve assembly
- The turning point includes a communication passage between the downstream pressure and the volume located upstream of the shutter assembly;
- the communication passage has a flared recess of determined dimensions to prevent the passage from being blocked by the lubricating grease of the turn
- 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 passage of the turn
- 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 shows schematically in section a device according to the invention, according to an assembly of two schematic half-views in axial section joined together, representing the device according to the invention in two different positions.

 FIG. 2 schematically represents in section along line II-II of FIG. 1 of a device according to the invention, according to an assembly of two schematic half-views in contiguous section.

 FIG. 3 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 in the upper half-view A and in the safety position in the lower half-view B.

 The device has an external conformation of a shut-off valve, for example with a ball or conical turn 1 mounted in a body 2 machined from stamped brass or equivalent metal and having threaded connection ends 3 and 4 allowing the device to be mounted on a gas pipeline, respecting the direction of passage and circulation of the gas identified by the arrow P.

 In known manner, the valve comprises a plastic actuating handle 5, cooperating with a stop plate 6 produced by stamping and a compensating spring 7 made of stainless steel or the like, and the turn 1 comprises ribs 8 of quarter turn stop.

 According to the invention, there is provided in the passage 10 of the turn 1 an annular groove 11 and a recess 11a machined directly to a diameter greater than that of the passage 10 and a seat 12 of diameter slightly greater than that of the passage 10, so as to retaining a shutter assembly 13 comprising a retaining means 14 of known type described in document 2,689,607 and a movable valve 15 cooperating with the seat 12 and sliding inside the passage 10 while being guided by fins 16.

The operation of the device is similar to that described in the document FR 2,689,607: above a predetermined value of the gas flow rate entering through the inlet 3, the shutter assembly moves from the position
A at position B in the direction of flow P of the gas until the valve 15 rests on the seat 12 and is held in position by the force exerted by the relative pressure of the gas on the exterior surface of the valve 15.

 After this automatic safety shutdown, it then suffices to actuate the turn 1 by a quarter of a turn by means of the lever 5 to allow the pressures to be balanced on either side of the valve 15 and the return to the position of the valve 15 by the retaining means 14: the device according to the invention is therefore automatically reset thanks to the minimal leaks between the seat 12 and the valve 15 which balance the pressures on either side of the valve 15.

 With reference to FIG. 2, the elements identified by numbers identical to those of FIG. 1 designate elements identical or similar to those of FIG. 1.

 The device according to the invention is shown in the closed position, position in which it interrupts the circulation of gas in the direction of passage P going from upstream 3 to downstream 4 and in which the downstream 4 is not subjected to no relative pressure.

 According to an advantageous variant of the invention, there is provided in the turn 1 a passage 20 for communication with the downstream 4 when the valve is closed.

 The passage 20 includes a recess 21 which is flared and preferably conical and a cylindrical bore located in the extension of this recess 21; the dimensions of the recess 21 are determined so that the grease applied to the turn 1 cannot block the passage 20 and prevent pressure balancing between the downstream 4 and the volume situated at the rear of the valve 15.

In this advantageous variant of the invention, the device is immediately reset by closing the valve, that is to say by passing from the position
B of Figure 1 in the position of Figure 2, due to the fact that the downstream pressure downstream of the valve 15 is immediately balanced through the passage 20 with the pressure upstream of the volume located at the rear of the valve 15 .

 In order to distinguish the device according to the invention from standard taps of known type, provision is advantageously made for practicing on the body 2 and / or on the handle 5 indicative machining or conformations such as, for example, an engraving of the tap body and / or an insertion of a colored patch or similar marking on the plastic of the handle.

 These indications provided for in the two variants but more particularly on the advantageous variant of the invention, specify the direction of passage P of the gas circulation which must be respected so that the passage 20 is in communication with the downstream during closure tap.

 Referring to Figure 3, a valve assembly 15 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 30 of diameter corresponding to that of the ring for fixing the retaining means, an enlarged portion 31 which is substantially conical and elastically deformable, a cylindrical fixing rod 32 on which the ring of the retaining means is mounted, a flange 33 constituting a stop for said ring to which it is connected a surface 34 having an aerodynamically shaped profile adapted to the gas flow.

 According to the invention, the valve assembly 15 has a substantially toroidal support and sealing configuration 35 in relief with respect to an annular groove 36, and the assembly 15 hollowed out internally comprises at least three guide fins arranged symmetrically by with respect to the axis CC of symmetry of the valve assembly and inside the geometrical cylinder radially limiting internally the annular groove 36.

 In the example shown comprising three fins, these three fins 16 are arranged 120 from one another around the axis C-C. Each fin 16 has a cylindrical contour 37 radiated so that, when guiding the valve assembly 15 in the passage 10, the possible contact between the passage 10 and the fin 16 is established substantially along a generatrix, notably reducing the friction between the fin 16 and the passage 10. To avoid any end bracing effect during guiding, provision is made to make a cut or chamfer 38 at an end A 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, 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 39.

 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 38 favoring guiding and the sliding of the valve assembly 15 inside the passage 10 of the turn 1.

 The valve assembly 15 which is hollowed out and of reduced mass is preferably made in one piece, by molding or a similar process providing continuity of material between the aforementioned elements 30 to 39 of a material of the nitrile rubber, elastomer or analogous 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.

Claims (10)

 1. - Automatic safety device forming a stop valve, of the type having a general conformation in a stop valve with a turn, characterized in that the turn (1) directly receives a shutter assembly (13), which is secured to it so as to interrupt the circulation of gas on exceeding a predetermined flow rate and so as to reset automatically when closing the turn (1).  2. - Device according to claim 1, characterized in that the turning (1) has a passage (10), in which is formed an annular groove (11) of diameter greater than that of the passage (10).  3. - Device according to claim 2, characterized in that the passage (10) further has a recess (lla) corresponding to the movement of a retaining means (14) of a valve assembly (15) movable.  4. - Device according to one of the preceding claims, characterized in that the turning (1) has a passage (20) for communication between the downstream pressure and the volume located upstream of the shutter assembly (13).  5. - Device according to claim 4, characterized in that said passage (20) of communication comprises a recess (21) flared of determined dimensions to avoid blockage of the passage (20) by the lubricating grease of the turn (1).  6. - Device according to claim 3, characterized in that the valve assembly (13) has a support and sealing configuration (35) substantially toroidal.  7. - Device according to claim 6, characterized in that said toroidal conformation (35) is in relief relative to an annular groove (36).  8. - Device according to claim 7, characterized in that the cylinder internally limiting said annular groove (36) comprises guide means (16) of the valve assembly (13) in the passage (10) of the turn (1 ).  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.