Assembly for retaining loose parts for a globe valve undergoing maintenance and method for installing same

Abstract

The invention relates in particular to an assembly (E) for retaining loose parts for a globe valve undergoing maintenance, characterised in that it comprises: - a first tubular element (4), a first upper end of which is open, while its second lower end is closed by a wall (41) and constitutes a retaining bottom; - a second tubular element (5) which is open at both opposite ends thereof. The invention also relates to a method for installing such an assembly (E) in a globe valve (1) undergoing maintenance.

Description

[0001] DESCRIPTION

[0002] TITLE: Migratory body retention assembly for a gate valve under maintenance and method for its installation

[0003] GENERAL TECHNICAL FIELD

[0004] The invention relates to the field of "FME risk" prevention for valve maintenance activities. 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 for the circuit to which the valve in question belongs.

[0005] 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, and numerous patent publications on FME are available, indicating a highly competitive environment in the field of innovation.

[0006] The invention relates more particularly to a retaining assembly for migrating bodies for a valve with a gate valve during maintenance and a method for installing such a retaining assembly in this valve.

[0007] STATE OF THE ART

[0008] In the nuclear power plant maintenance sector, it is common to find pieces of graphite gaskets and metal filings at the base of fuel assemblies during each maintenance shutdown.

[0009] This necessitates the systematic cleaning of the bases of the affected fuel assemblies, because a fuel assembly containing a foreign object, also known as a "migrating object," cannot be refilled in a reactor vessel and cannot be transported to a reprocessing facility at the end of its service life. This fuel assembly cleaning activity has both dosimetric and financial costs, and it is time-consuming.

[0010] Furthermore, not all migrating particles such as graphite or metal 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.

[0011] After analyzing the activities that could generate this type of migrating body, the following maintenance activities were identified:

[0012] Scraping the sealing gasket of the valves in the reactor's primary circuit;

[0013] Lapping and machining of the sealing surfaces of the valves in this primary circuit.

[0014] These activities are carried out with a system of depressurizing the circuit to prevent the dispersion of contamination outside the tap being maintained.

[0015] Therefore, there is a need for a device to prevent graphite fragments or metal filings from falling into the system, while also allowing for system depressurization to protect personnel from contamination. Ideally, the device should also be adaptable to a valve without a system for creating system depressurization.

[0016] In prior art, there are plugs that can be fitted inside taps. They are placed on either side of the tap to be inspected and prevent foreign matter generated by maintenance work from being discharged into the system.

[0017] However, these plugs 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 required to create negative pressure. 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. Finally, removing the plug does not allow for the direct collection of any foreign particles generated. These particles must be collected by a separate suction system, the transport and bulk of which on the worksite complicate the work for workers.Indeed, work sites are often cramped, must already contain the tools and spare parts needed for the project, and are generally shared with other contractors. There isn't always room to position a vacuum cleaner. Furthermore, accessing these work sites often involves gratings, stairs, and narrow passages, which make it difficult to move the vacuum cleaner to the work area.

[0018] Finally, using a vacuum cleaner requires an electrical outlet, which isn't always nearby or is already in use. This can complicate setup and / or delay the vacuum cleaner's use. All these constraints related to this equipment mean that, generally, workers don't take it with them to job sites.

[0019] This means that when they generate pieces of graphite or filings during maintenance, they may recover the largest pieces but not all of what can be recovered.

[0020] The prior art documents listed below relate primarily 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 obstructing the tap's operation: US2023375031, US2022128183, US2020232591, KR102063589, US2018363826, US2015316194, US2015060451, W02014152318, JP2012177692, CN116899298, CN220227973 (U), CN218677475 (U), JP2022158492, CN217784837(U), CN216951868(U), CN114381284, JP2015118134.

[0021] 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 shut down, and that can be used, if necessary, to create a negative pressure in the area surrounding the tap. PRESENTATION OF THE INVENTION

[0022] According to the invention, a migrating body retention assembly is proposed for a gate valve during maintenance, characterized in that it comprises:

[0023] - a first tubular element whose first upper end is open, while its second lower end is closed by a wall and constitutes a retaining bottom;

[0024] - a second tubular element open at its two opposite ends.

[0025] Thus, the invention consists of a type of sealing system that is positioned inside taps. It was designed specifically for taps located in controlled areas, although it can be used in other industrial sectors.

[0026] 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.

[0027] It also allows for the direct retrieval of migrating bodies, avoiding the use of suction equipment, for example.

[0028] The invention addresses the following needs:

[0029] Prevention of migrant bodies falling into circuits;

[0030] Prevention of contamination and / or fouling of circuits.

[0031] Depending on other advantageous and non-limiting features of this device, taken alone or in any technically compatible combination of at least two of them:

[0032] - the tubular wall of said elements is solid, that is to say not perforated.

[0033] Thanks to this feature, the assembly according to the invention is particularly suitable for a tap whose environment is not under negative pressure.

[0034] - the tubular wall of said elements is at least partially perforated. Thanks to this feature, the assembly according to the invention is particularly suitable for a tap operating in a negative pressure environment.

[0035] - each of said elements has a circular cross-section and is single-diameter.

[0036] Thanks to this feature, the elements adapt perfectly to the configuration of the tap body.

[0037] - said elements have different diameters.

[0038] Thanks to this feature, the elements adapt to the different sizes of valve body sizes that exist.

[0039] - the wall of said first element which constitutes a retaining base has a projecting member directed towards the inside of this element, and which constitutes a gripping member.

[0040] Thanks to this feature, removing the first element is made easier.

[0041] 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:,

[0042] - placement of said first element in said first chamber until said retaining wall is against the bottom of said first chamber;

[0043] - placement of said second element so that it rests against said annular support surface.

[0044] Thanks to these characteristics, the assembly according to the invention is particularly easy to set up.

[0045] DESCRIPTION OF THE FIGURES

[0046] 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.

[0047] Figure 1 is a partial view, along a vertical section plane, of a known type of globe valve to which the present invention may apply.

[0048] Figure 2 is a view analogous to Figure 1, with the tap cap removed and the assembly according to the invention placed in the tap body.

[0049] Figure 3 is a perspective view of one possible embodiment of a first element of the assembly according to the invention.

[0050] Figure 4 is a perspective view of one possible embodiment of a second element of the assembly according to the invention.

[0051] Figure 5 is a top view of a tap with its cap removed and into which the elements shown in the two previous figures have been inserted.

[0052] DETAILED DESCRIPTION OF THE INVENTION

[0053] Before describing the assembly E according to the present invention, reference will be made to figure 1 on which a valve 1, generally used in many industries, is partially represented.

[0054] 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 partially shown in figure 1, the lower end of which is fitted with a valve 22 (also called a flapper or stopper).

[0055] The cap 2 delimits with the body 10 two lower and upper chambers, respectively referenced 11 and 12.

[0056] The lower chamber 11, with a 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.

[0057] 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 larger diameter than 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.

[0058] 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.

[0059] We have referenced 23 and 24 the annular zones of the body 10 in which are present, in an operating state of the tap 1, sealing joints, respectively of the cap 2 vis-à-vis the body and of the valve 22 vis-à-vis the frustoconical surface 121.

[0060] These are 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 figure 2.

[0061] The first and second elements of assembly E according to the invention are visible in figures 3 and 4.

[0062] The first element 4 shown in Figure 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.

[0063] 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.

[0064] As can be seen in Figure 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.

[0065] 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 chamber 11 by bearing against the bottom of the chamber.

[0066] Its height is chosen so that its tubular wall closes off branch 30 of channel 3, while leaving the aforementioned truncated conical surface 121 accessible.

[0067] The second element 5 in Figure 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.

[0068] 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 chamber 12 by bearing against the bottom of the aforementioned annular surface 120.

[0069] Its height is chosen so that its tubular wall will block branch 31 of channel 3, while leaving accessible zone 24 which was mentioned above.

[0070] As mentioned above, current sealing systems do not allow for the direct recovery of migrating bodies generated by valve maintenance activities, nor do they secure against the risk of contamination for those involved.

[0071] The assembly according to the invention makes it possible to address this problem.

[0072] 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, one can proceed in the following manner.

[0073] While the tap 1 has been freed from its cap 2 and is therefore in the situation of figure 2, the first element 4 is put in chamber 11 and then the second element in chamber 12. The necessary interventions (scraping, graphite removal and machining) are then carried out in areas 23 and 24. This work is in no way hindered by elements 4 and 5, due to their height which makes access to these areas free.

[0074] On this occasion, the graphite debris and shavings that have been generated fall by gravity into element 4 where they are stored.

[0075] We then proceed to remove element 5, then element 4 (the removal of the latter is facilitated by the presence of the protruding organ 410 which forms a grasping organ.

[0076] The assembly according to the invention thus allows the internal openings of the tap to be sealed while still permitting access to critical areas for the technician. Therefore, the technician experiences no hindrance in their work.

[0077] The E set 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 can be cumbersome for the users.

[0078] In the preceding discussion, it was assumed that the area around the tap had been previously depressurized. However, because components 4 and 5 have a tubular wall that is at least partially perforated, air circulation 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 a guideline, the largest dimension of these perforations can be less than 2 millimeters, preferably 1.5 millimeters.

[0079] In a situation where the tap is not subjected to a vacuum, elements 4 and 5 can be used whose tubular wall is solid, i.e. without openings.

[0080] With a few adjustments to shape and / or dimensions, the E assembly is suitable for all types of valve taps.

[0081] 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.

[0082] Users face no constraints in deploying it: no tools are needed, no extra 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.

[0083] 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

1. DEMANDS 1. Migratory body retention assembly (E) for a globe valve (1) under maintenance, the globe valve comprising a body (10) having a first lower cylindrical chamber (11) extending along a longitudinal axis, and a second upper cylindrical chamber (12) extending along the longitudinal axis, the first lower chamber (11) being directly aligned and in fluid communication with the second upper chamber (12), the first lower chamber (11) having a bottom opposite to the second upper chamber (12) with respect to the first lower chamber (11), such that the first lower chamber (11) is blind, and the second chamber (12) has a diameter greater than the diameter of the first chamber (11); a fluid circulation channel (3) comprising an upstream branch (30) and a downstream branch (31), the upstream branch (30) being in fluid communication with the first lower chamber (11) and the downstream branch (31) being in fluid communication with the second upper chamber (12). The second upper chamber (12) being adapted to receive an operating stem (21) of a cap (2) of the gate valve, the operating stem (21) having a lower end provided with a valve (22), so as to close the fluid circulation channel (3), the cap (2) being removed during maintenance, the assembly being characterized in that it comprises: - a first tubular element (4) comprising a tubular wall extending between a first open upper end (40), and a second lower end closed by a wall (41), - a second tubular element (5) comprising a tubular wall extending between two opposite open ends (51,52); the second tubular element (5) being suitable for insertion into the second upper chamber (12), and the first tubular element (4) being suitable for insertion into the first lower chamber (11), the wall (41) being in contact with the bottom of the first lower chamber (11); and the tubular wall of the first tubular element (4) includes a solid lower part (42), so that migrating bodies, generated during maintenance, are drawn by gravity inside the first tubular element (4) towards the wall (41) and retained by the solid lower part (42).

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

3. Assembly (E) according to claim 1, characterized in that the tubular wall of the first tubular element (4) further comprises a perforated upper part (43).

4. Assembly (E) according to any one of claims 1 and 3, characterized in that the tubular wall of the second tubular element (5) comprises a perforated part (50).

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

6. Assembly (E) according to any one of claims 1 to 5, characterized in that the second tubular element (5) has a diameter greater than or equal to the diameter of the first tubular element (4).

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

8. Method of installing an assembly (E) according to any one of claims 1 to 7 in a gate valve (1) during maintenance, the valve body (10) being without its cap (2) equipped with an operating stem (21) the lower end of which is provided with a valve (22), this body (10) comprising a first lower chamber (11), cylindrical and blind, directed along a longitudinal axis, which communicates with an upstream branch (30) of a fluid circulation channel (3), the first lower chamber (11) being arranged in continuity and in alignment with a second upper cylindrical chamber (12) while communicating with it, the second lower chamber (12) having a diameter greater than that of the first upper chamber (11), and communicating with a downstream branch (31) of said fluid circulation channel (3), the second upper chamber (12) being configured to receive said operating rod (21), a 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 the valve (22), characterized in that it comprises the following steps: - placement of said first tubular element (4) in said first lower chamber (11) until said wall (41) is against the bottom of this first lower chamber (11); - placement of said second tubular element (5) in said second upper chamber (12), so that it rests against said annular support surface (121).

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