Assembly for retaining migrating bodies for a gate valve under maintenance and method for its installation

Abstract

The invention relates in particular to a retaining assembly (E) for a gate valve during maintenance, characterized in that it comprises: - a first tubular element (4) having one upper end open, while its second lower end is closed by a wall (41) and constitutes a retaining base; - a second tubular element (5) open at its two opposite ends. Figure 5 (for the abbreviation)

Description

Title of the invention: Retaining assembly for migrating bodies for a gate valve during maintenance and method for its installation

[0001] GENERAL TECHNICAL DOMAIN

[0002] The invention relates to the field of "FME risk" prevention for valve maintenance activities. The object of the invention can be used in all areas of industry where valve maintenance is carried out with a vacuum system, but also without a vacuum system in the circuit to which the valve in question belongs.

[0003] The field of FME (Foreign Material Exclusion) risk prevention is very active in the innovation sector. New products are launched on the global market every year. Numerous patent publications on the topic of FME are available, indicating a highly competitive environment in the field of innovation.

[0004] The invention relates more particularly to a retaining assembly for migrating bodies for a valve with a globe during maintenance and a method for installing such a retaining assembly in this valve. STATE OF THE ART

[0005] In the nuclear power plant maintenance sector, it is common to find, at each maintenance shutdown, pieces of graphite seals and filings at the base of the fuel assemblies.

[0006] This necessitates the systematic cleaning of the bases of the assemblies concerned, because a fuel assembly containing a foreign body, also called a "migrating body," cannot be refilled in a tank and cannot be sent to its reprocessing facility when it reaches the end of its life. This fuel assembly cleaning activity has a cost, both in terms of dosage and finances, and is time-consuming.

[0007] Furthermore, not all migrating bodies such as graphite or filings end up at the base of the assembly. Indeed, they can lodge in different areas of the circuit and, for example, disrupt valve seals, or be activated by irradiation and generate hot spots in the circuits of the building housing the reactor.

[0008] After analyzing the activities that could generate this type of migrating body, the following maintenance activities were identified:

[0009] - Scraping the sealing gasket of the valves in the primary circuit of the reactor;

[0010] - Lapping and machining of the sealing surfaces of the valves of this primary circuit.

[0011] These activities are carried out with a system for depressurizing the circuit to prevent the dispersion of contamination outside the tap being maintained.

[0012] There is therefore a need for a device to prevent pieces of graphite or filings from falling into the circuit, while also allowing the circuit to be depressurized and thus protecting personnel from contamination. Ideally, the device should also be adaptable to a valve without a system for depressurizing the circuit.

[0013] In the prior art, there are plugs that can be placed inside taps. They are positioned on either side of the tap to be inspected and prevent migrating bodies generated by maintenance activity from being discharged into the circuit.

[0014] However, they do not allow the negative pressure system to protect workers from the risk of contamination. Indeed, the current plugs completely block the circuit and do not allow the suction created by the negative pressure system to pass through. This suction is necessary to keep the contamination contained within the circuit instead of entering the work area and contaminating workers. Furthermore, installing and removing these plugs requires reaching into the valve, which can also pose a risk of contamination for workers.

[0015] Finally, they do not allow, in conjunction with the removal of the shutter, for the direct recovery of the generated debris. The debris must be recovered by an auxiliary suction system, the transport and bulk of which on the worksite complicate the task for those involved. Indeed, work areas are often cramped, must already contain the tools and spare parts needed for the project, and are generally shared with other workers. There is not always room to position a vacuum cleaner. Moreover, accessing these work areas often involves gratings, stairs, and narrow passages, which do not facilitate transporting the vacuum cleaner to the work area.

[0016] Finally, using a vacuum cleaner requires an electrical outlet, which is not always nearby or is already in use. This can complicate setup and / or delay the use of the vacuum cleaner. All these constraints related to this equipment mean that, generally, workers do not take it with them to construction sites.

[0017] This means that when they generate pieces of graphite or filings during maintenance, they eventually recover the largest pieces but not all of what can be recovered.

[0018] The prior art documents listed below relate mainly to sealing systems such as those mentioned above or to filtration systems installed inside taps during operation, to prevent migrating bodies in the circuit from hindering the operability of the tap: US2023375031, US2022128183, US2020232591, KR102063589, US2018363826, US2015316194, US2015060451, WO2014152318, JP2012177692, CN116899298, CN220227973 (U), CN218677475 (U), JP2022158492, CN217784837(U), CN216951868(U), CN114381284, JP2015118134.

[0019] The present invention aims to provide a simple and practical solution to at least some of these problems by proposing a device that retains foreign bodies in a tap during maintenance, i.e., when it is shut down, and that can be used, if necessary, to create a negative pressure in the environment surrounding the tap. PRESENTATION OF THE INVENTION

[0020] According to the invention, a migrating body retention assembly is proposed for a gate valve during maintenance, characterized in that it comprises:

[0021] - a first tubular element having a first open upper end, while its second lower end is closed by a wall and constitutes a retaining bottom;

[0022] - a second tubular element open at its two opposite ends.

[0023] Thus, the invention consists, in a way, of a sealing system that is positioned inside taps. It was designed in particular for taps located in controlled areas, although it can be used in other industrial sectors.

[0024] This innovation helps to prevent the risk of falling migrating bodies during the phases of joint removal / scraping, lapping / machining of the seats or even cleaning of the tap seats.

[0025] It also allows for the direct recovery of migrating bodies, avoiding the use of suction equipment, for example.

[0026] The invention meets the following needs:

[0027] - Prevention of falling migrant bodies in circuits;

[0028] - Prevention of contamination and / or fouling of circuits.

[0029] According to other advantageous and non-limiting features of this device, taken alone or in any technically compatible combination of at least two of them:

[0030] - the tubular wall of said elements is solid, that is to say not perforated.

[0031] Thanks to this feature, the assembly according to the invention is particularly suitable for a tap whose environment is not under vacuum.

[0032] - the tubular wall of said elements is at least partially perforated.

[0033] Thanks to this feature, the assembly according to the invention is particularly suitable for a tap whose environment is under vacuum.

[0034] - each of said elements has a circular cross-section and is single diameter.

[0035] Thanks to this feature, the elements adapt best to the configuration of the tap body.

[0036] - said elements have different diameters.

[0037] Thanks to this feature, the elements adapt to the different sizes of valve body sizes that exist.

[0038] - the wall of said first element which constitutes a retaining base comprises a component protruding, directed towards the inside of this element, and which constitutes a grasping organ.

[0039] Thanks to this feature, the removal of the first element is facilitated.

[0040] The present invention also relates to a method of installing an assembly according to one of the preceding characteristics in a gate valve during maintenance, the body of this valve being devoid of its cap equipped with an operating stem, this body comprising a first lower chamber, cylindrical and blind, directed along a longitudinal axis, which communicates with the upstream branch of a fluid circulation channel, this first chamber being arranged in continuity and in alignment with a second upper cylindrical chamber while communicating with it, this second chamber, having a diameter greater than that of the first chamber, which communicates with the downstream branch of said fluid circulation channel, being configured to receive said operating stem,the transition zone between said first and second chambers having an annular bearing surface which extends into a frustoconical surface constituting a seat for said valve, characterized in that it comprises the following stages: ,

[0041] - placement of said first element in said first chamber until said wall forming the retaining wall is abutted against the bottom of this first chamber;

[0042] - placing said second element so that it supports against said annular support surface.

[0043] Thanks to these characteristics, the installation of the assembly according to the invention is particularly easy. DESCRIPTION OF THE FIGURES

[0044] Other features and advantages of the invention will become apparent from the description which will now be given, with reference to the attached drawings, which represent, by way of example but not limitation, at least one possible embodiment.

[0045] On these drawings:

[0046] Fig. 1 is a partial view, along a vertical cutting plane, of a known type of globe valve, to which the present invention may be applied;

[0047] [Fig.2] is a view analogous to [Fig.1], the tap cap having been removed and the assembly according to the invention placed in the tap body;

[0048] The [Fig.3] is a perspective view of a possible embodiment of a first element of the assembly according to the invention;

[0049] Fig. 4 is a perspective view of one possible embodiment of a second element of the assembly according to the invention;

[0050] Figure 5 is a top view of a tap with its cap removed and into which the elements shown in the two preceding figures have been inserted. DETAILED DESCRIPTION OF THE INVENTION

[0051] Before describing the assembly E according to the present invention, reference will be made to [Fig.1] on which is partially represented a valve 1 generally used in many industries.

[0052] This tap comprises a body 10 surmounted by a cap 2, which has a vertically oriented through opening 20. Through this opening 20 is engaged an operating stem 21 shown partially in [Fig. 1], the lower end of which is provided with a valve 22 (also called a poppet or shutter).

[0053] The cap 2 delimits with the body 10 two lower and upper chambers, respectively referenced 11 and 12.

[0054] The lower chamber 11, with longitudinal and vertical axis, is cylindrical and blind. It communicates with the upstream branch 30 of a fluid circulation vein 3, which is located on the left of the figure.

[0055] This first chamber 11 is located in continuity and alignment, vertically above a second upper chamber 12, forming a counterbore. This chamber is also cylindrical and has a diameter greater than that of the first chamber. It communicates with the downstream branch 31 of the fluid circulation vein 3, which is located on the right of the figure.

[0056] The transition zone between these two chambers 11 and 12 is materialized by an annular support surface 120 generally perpendicular to the axis of the chambers, which surrounds a frustoconical surface 121 and which constitutes the seat against which the valve is configured to come to rest, in order to close the fluid circulation vein 3.

[0057] Annular zones of the body 10 are referenced 23 and 24 in which, in an operating state of the tap 1, there are sealing joints, respectively of the cap 2 vis-à-vis the body and of the valve 22 vis-à-vis the frustoconical surface 121.

[0058] It is these areas 23 and 24 on which we wish to work, with a view to scraping the seal or lapping and machining the seal surfaces. To do this, we operate after removing the cap 2, as illustrated in [Fig.2].

[0059] The first and second elements of assembly E according to the invention are visible in figures 3 and 4.

[0060] The first element 4 shown in [Fig. 3] is a tubular element whose first end 40 (here the upper end) is open, while its second lower end consists of a wall 41 and thus forms a retaining base. The shape of this first element is therefore similar to that of a cup.

[0061] In the embodiment presented here, its tubular wall comprises a solid lower part 42 and a perforated upper part 43, the openings being referenced 430.

[0062] As can be seen in [Fig. 5], the wall 41 of said first element 4, which constitutes a retaining base, has a projecting member 410 directed towards the interior of this element, and which constitutes a gripping member. Its function will be specified later in the description.

[0063] This first element 4 has a circular cross-section and a uniform diameter over its entire length. Its outer diameter is chosen, within the limits of clearance, so that it can be engaged in the chamber 11 by bearing against the bottom of the latter.

[0064] Its height is chosen so that its tubular wall closes off branch 30 of channel 3, while leaving the aforementioned frustoconical surface 121 accessible.

[0065] The second element 5 of [Fig. 4] is also a tubular element, but its opposite ends 51 and 52 are open. Its tubular wall 50 has perforations 500 over its entire surface.

[0066] This second element 5 also has a circular cross-section and a uniform diameter over its entire length. Its outer diameter is chosen, within the limits of clearance, so that it can be engaged in the chamber 12 by bearing against the bottom of the aforementioned annular surface 120.

[0067] Its height is chosen so that its tubular wall will close off branch 31 of channel 3, while leaving accessible the area 24 mentioned above.

[0068] As mentioned above, current sealing systems do not allow either the direct recovery of migrating bodies generated by valve maintenance activities, or the securing of the risk of contamination of the workers.

[0069] The assembly according to the invention makes it possible to address this problem.

[0070] Thus, when it is proposed to carry out maintenance on a tap such as that in figures 1 and 2 by intervening on areas 23 and 24 which are potentially generating migrating bodies, the following procedure can be followed.

[0071] While the tap 1 has been freed from its cap 2 and is therefore in the situation of [Fig.2], the first element 4 is put in the chamber 11 and then the second element in the chamber 12. The necessary operations (scraping, graphite removal and machining) are then carried out in the areas 23 and 24. This work is in no way hindered by the elements 4 and 5, due to their height which makes access to these areas free.

[0072] On this occasion, the graphite debris and chips that have been generated fall by gravity into element 4 where they are stored.

[0073] Element 5 is then removed, followed by element 4 (the removal of the latter is facilitated by the presence of the protruding organ 410 which forms a grasping organ.

[0074] The assembly according to the invention therefore allows the internal openings of the tap to be sealed while still allowing the technician access to critical areas. Thus, the technician experiences no hindrance in their work.

[0075] Assembly E also allows for the retrieval of cloths and emery cloths used to clean the staves, which can sometimes slip from the user's hand. Indeed, such accessories are rarely secured with a fastening system because this is a hindrance to the users.

[0076] In the preceding text, it was assumed that the environment around the tap had been previously placed under negative pressure. However, since elements 4 and 5 have a tubular wall that is at least partially perforated, the circulation of air within the tap body is not impeded. Nevertheless, the perforations must be small enough to both trap small migrating particles and allow the negative pressure of the circuit to pass through. As an example, the largest dimension of these perforations may be less than 2 millimeters, preferably 1.5 millimeters.

[0077] In a situation in which the tap is not subjected to a vacuum, elements 4 and 5 can be used whose tubular wall is solid, i.e. without openings.

[0078] With some adaptations of shape and / or dimensions, the E assembly is suitable for any type of valve tap.

[0079] The present invention can be implemented for any valve maintenance in any industrial environment. It allows, through simple deployment by the technicians, the systematic recovery of foreign matter generated during valve maintenance.

[0080] Users face no constraints in deploying it: no tools are needed, no additional time is required for installation, and no heavy or complex handling is necessary. It allows for the easy retrieval of migrating bodies without additional equipment (e.g., a vacuum cleaner), by extracting assembly E from the tap.

[0081] For the equipment operator, the presence of migrating bodies from valve maintenance is eliminated, and therefore the impacts related to migrating bodies (safety, radiation protection, technical (leakage related to the presence of migrating bodies, fouling of circuits...), costs, availability...).

Claims

Demands

1. Migratory body retention assembly (E) for a valve (1) with a gate valve during maintenance, characterized in that it comprises: - a first tubular element (4) of which a first upper end (40) is open, while its second lower end is closed by a wall (41) and constitutes a retention bottom; - a second tubular element (5) open at its two opposite ends (51,52).

2. Assembly (E) according to claim 1, characterized in that the tubular wall of said elements (4,5) is solid, i.e. not perforated.

3. Assembly (E) according to claim 1, characterized in that the tubular wall of said elements is at least partially perforated (43,50).

4. Assembly (E) according to any one of claims 1 to 3, characterized in that each of said elements (4,5) has a circular cross section and is single diameter.

5. Assembly (E) according to claim 4, characterized in that said elements (4,5) have different diameters.

6. Assembly (E) according to any one of claims 1 to 5, characterized in that the wall (41) of said first element (4) which constitutes a retaining base has a projecting member (410) directed towards the interior of this element, and which constitutes a gripping member.

7. A method for installing an assembly (E) according to any one of claims 1 to 6 in a gate valve (1) undergoing maintenance, the body (10) of this valve being without its cap (2) equipped with an operating stem (21), this body (10) comprising a first lower chamber (11), cylindrical and blind, oriented along a longitudinal axis, which communicates with the upstream branch (30) of a fluid circulation channel (3), this first chamber (11) being arranged in continuity and alignment with a second upper cylindrical chamber (12) while communicating with it, this second chamber (12), having a diameter greater than that of the first chamber (11), which communicates with the downstream branch (31) of said circulation channel (3) of fluid, being configured to receive said operating rod (21), the transition zone between said first and second chambers (11,12) having an annular bearing surface (120) which extends into a frustoconical surface (121) constituting a seat for said valve, characterized by the fact that it comprises the following stages: - placing said first element (4) in said first chamber (11) until said wall (41) forming bottom of retention is against the bottom of said first chamber (11); - placing said second element (5) so that it rests against said annular support surface (121).

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