Manhole foreign matter prevention cover plate

Abstract

The utility model discloses an anti-foreign-matter cover plate for a manhole. The manhole foreign matter prevention cover plate comprises a manhole protection face, the manhole protection face comprises a center part and an edge part, the center part is connected with the edge part, the center part is provided with a drying pipe opening and at least two observation holes, the edge part is provided with a plurality of installation holes, and the drying pipe opening is used for allowing a drying air pipe to penetrate and be fixed; the mounting hole is used for fixing the manhole protection surface and the manhole sealing surface; and the drying pipe opening cover plate is overturned relative to the manhole protection surface and is used for opening or closing the drying pipe opening. The manhole foreign matter prevention cover plate is provided with the drying pipe opening, the sealing performance and the purging effect of the drying pipe during purging of the heat transfer pipe are improved, the observation hole is formed, pipe plate state monitoring and monitoring camera cable passing are facilitated, and the foreign matter prevention effect and the field operation convenience are improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of nuclear power station overhauls, especially relates to a manhole anti-foreign cover plate. BACKGROUND

[0002] Passive residual heat removal system (PRHR) is an important safety facility of passive nuclear power plant, and most of the core decay heat is transferred to the built-in refueling water tank through the PRHR heat exchanger under the whole plant power failure. The PRHR heat exchanger is usually a C-shaped frame structure, and there are upper and lower two heads and tube sheets, during the in-service inspection of the nuclear power plant, compressed air needs to be introduced from the manhole for heat transfer tube purging and drying after the manhole of the PRHR heat exchanger is opened. In order to avoid the opening of the manhole and prevent foreign matters from entering during the drying tube purging process, an anti-foreign manhole cover plate is usually arranged, and the traditional anti-foreign cover plate is mainly designed as a single flat plate or a dense mesh. During the in-service eddy current inspection of the steam generator, even if a cable is used, the whole cover plate needs to be opened, which not only has poor flexibility, but also increases the radiation dose, increases the loose contamination overflow rate and increases the personnel radiation dose. SUMMARY

[0003] The utility model provides a kind of manhole anti-foreign cover plate to reduce radiation overflow in the process of overhaul.

[0004] The utility model embodiment provides a kind of manhole anti-foreign cover plate, the manhole anti-foreign cover plate includes:

[0005] Manhole protection surface, the manhole protection surface includes center part and edge portion, the center part is connected with the edge portion, the center part is provided with drying pipe mouth and at least two observation holes, the edge portion is provided with a plurality of mounting holes, the drying pipe mouth is used for drying air pipe to enter and fixed;The mounting hole is used for the fixation of the manhole protection surface and manhole sealing surface;

[0006] Drying pipe mouth cover plate, the drying pipe mouth cover plate is overturned relative to the manhole protection surface, and is used for the opening or closing of the drying pipe mouth.

[0007] Optionally, the thickness of the center part is less than the thickness of the edge portion.

[0008] Optionally, the drying pipe mouth is arranged at the center of the center part.

[0009] Optionally, the drying pipe mouth cover plate and the center part are connected by hinge.

[0010] Optionally, the aperture of the drying pipe mouth is same with the aperture of the drying air pipe.

[0011] Optionally, the at least two observation holes include a first observation hole and a second observation hole, and the first observation hole and the second observation hole are symmetrically arranged relative to the drying pipe opening.

[0012] Optionally, the observation hole is in an elliptical or circular shape.

[0013] Optionally, the manhole protection surface and the manhole sealing surface are connected by bolts.

[0014] Optionally, the plurality of mounting holes include a first mounting hole, a second mounting hole, a third mounting hole, and a fourth mounting hole, the first mounting hole and the second mounting hole are symmetrically arranged relative to the drying pipe opening, and the third mounting hole and the fourth mounting hole are symmetrically arranged relative to the drying pipe opening.

[0015] Optionally, an isolation pad is arranged between the edge portion of the manhole protection surface and the manhole sealing surface.

[0016] The technical scheme of the embodiment of the utility model provides a manhole anti-foreign cover plate, the manhole anti-foreign cover plate includes: manhole protection surface, the manhole protection surface includes center portion and edge portion, the center portion is connected with the edge portion, the center portion is provided with drying pipe opening and at least two observation holes, and the edge portion is provided with a plurality of mounting holes, and the drying pipe opening is used for drying the wind pipe to enter and fix;The mounting hole is used for fixing the manhole protection surface and the manhole sealing surface;Drying pipe opening cover plate, the drying pipe opening cover plate is overturned relative to the manhole protection surface, and is used for the opening or closing of drying pipe opening.The manhole anti-foreign cover plate is arranged in the drying pipe opening, improves the sealing property and purging effect of drying pipe when heat transfer pipe purges, and the observation hole is arranged, the tube plate state monitoring and monitoring camera cable are passed through, and the anti-foreign effect and on-site operation convenience are improved.

[0017] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the utility model, and is not used to limit the scope of the utility model. Other features of the utility model will become easy to understand through the following description. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical scheme in the embodiment of the utility model, the drawings needed to be used in the embodiment description will be briefly introduced below, and obviously, the drawings in the following description are only some embodiments of the utility model, and other drawings can be obtained according to these drawings without creating labor for those skilled in the art.

[0019] Figure 1 A structural schematic diagram of a manhole anti-foreign cover plate is provided for the embodiment of the utility model;

[0020] Figure 2 For Figure 1A cross-sectional structure schematic diagram along the cross-sectional line AA'. DETAILED DESCRIPTION

[0021] In order to make the technical personnel in the art better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should belong to the scope of protection of the present application.

[0022] It should be noted that, in the description of the present application, unless otherwise explicitly specified and limited, the terms "connected", "connected", "fixed" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For ordinary skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0023] In the present application, unless otherwise explicitly specified and limited, the "upper" or "lower" of the first feature to the second feature can include the direct contact of the first and second features, or can include the contact of the first and second features through another feature between them. Moreover, the "upper", "upper" and "upper" of the first feature to the second feature include the vertical and oblique above of the first feature to the second feature, or only indicate that the horizontal height of the first feature is higher than that of the second feature. The "below", "below" and "below" of the first feature to the second feature include the vertical and oblique below of the first feature to the second feature, or only indicate that the horizontal height of the first feature is less than that of the second feature.

[0024] In the description of the present embodiment, the terms "upper", "lower", "right", and other orientation or position relationship are based on the orientation or position relationship shown in the drawings, only for the convenience of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" are only used to distinguish in description, and have no special meaning.

[0025] Nuclear power plant in-service inspection is one of the important links to ensure the safe operation of nuclear power plant, passive residual heat removal heat exchanger is a nuclear power plant nuclear level one equipment, and is also a nuclear reactor primary loop pressure boundary, according to the regulatory requirements, the manhole should be opened during the overhaul of the unit, the heat transfer tube is dried and the eddy current inspection is implemented. After the opening of the head manhole of the passive residual heat removal heat exchanger, compressed air and the like need to be introduced from the manhole to blow and dry the heat transfer tube. The heat transfer tube drying needs to connect the compressed air pipe from the manhole, fix it and reduce the air volume loss as much as possible, and shield the boron water splashing and loose pollutants blown out. At the same time, the manhole needs to be strictly prevented from entering the passive residual heat removal heat exchanger water chamber before being opened and closed again, so as to prevent the serious foreign matter invasion consequences caused by entering the primary loop. The traditional foreign matter protection cover plate is mainly designed as a single flat plate or a dense mesh, which can only be used for the closure and foreign matter protection of the manhole during the inspection interval and interruption, and needs to be removed again and temporarily stored in the radioactive contamination control area after the resumption of the inspection. The heat transfer tube full tube drying generally directly connects the air pipe to the manhole, and temporarily blocks it by using the radiation protection plastic cloth and adhesive tape, and the blocking is re-pasted after being opened to check the drying effect, which is easy to lose air volume and has poor working efficiency, and the blocking material itself is also easy to fall into the water chamber as foreign matter.

[0026] Accordingly, the embodiment provides a manhole foreign matter protection cover plate.

[0027] Figure 1 A structure diagram of the manhole foreign matter protection cover plate is provided for the embodiment of the utility model, Figure 2 For Figure 1 The cross-sectional structure diagram along the section line AA' is shown in Figure 1 and Figure 2 The manhole foreign matter protection cover plate 100 comprises a manhole protection surface 101, the manhole protection surface 101 comprises a center part 1011 and an edge part 1012, the center part 1011 is connected with the edge part 1012, the center part 1011 is provided with a drying pipe opening 102 and at least two observation holes 103, the edge part 1012 is provided with a plurality of mounting holes 104, the drying pipe opening 102 is used for the penetration and fixation of the drying air pipe; the mounting hole 104 is used for the fixation of the manhole protection surface 101 and the manhole sealing surface; the drying pipe opening cover plate 105 is turned over relative to the manhole protection surface 101, and is used for the opening or closing of the drying pipe opening 102.

[0028] The manhole anti-foreign cover plate 100 is circular in shape, and is provided with a manhole protection surface 101 that can prevent foreign matter from entering the interior of the water chamber and can also protect the manhole sealing surface. The manhole anti-foreign cover plate 100 can be designed to be light and thin, and has a thickness of 3-5 mm, and is easy to process and dispose. The manhole protection surface 101 of the manhole anti-foreign cover plate 100 can be divided into a central portion 1011 and an edge portion 1012. The central portion 1011 is provided with a drying pipe opening 102. The drying pipe opening 102 is circular in shape and corresponds to the shape of the drying pipe. The drying pipe opening 102 is used for the passage, fixation and sealing of the drying air pipe during the drying of the heat transfer pipe, and can eliminate the temporary fixation and sealing operation during the blowing of the heat transfer pipe, reduce the air volume loss, block the splashing of boron water and loose pollutants during blowing, and improve the sealing performance of the drying air pipe and the blowing effect. The central portion 1011 is also provided with at least two observation holes 103, which can be used to observe the tube plate in real time and facilitate the insertion of monitoring camera cables, and can be used to check the drying state of the heat transfer pipe in real time. When the observation holes 103 are not used, on-site foreign matter prevention adhesive tape can be used for sealing to prevent foreign matter from entering, which is convenient and fast. The edge portion 1012 of the manhole protection surface 101 is provided with a plurality of mounting holes 104, which are used to fix the manhole protection surface 101 and the manhole sealing surface, and ensure the protection effect of the manhole protection surface 101 on the manhole sealing surface. The number of mounting holes 104 can be selected according to actual design requirements, and can be 4, 8, 12, 16, etc., to ensure the connection effect between the manhole protection surface 101 and the manhole sealing surface. The manhole protection surface 101 also includes a drying pipe opening cover plate 105 that is flipped relative to the manhole protection surface 101. When the drying pipe opening 102 is in use, the drying pipe opening cover plate 105 is opened to facilitate the passage and fixation of the drying air pipe for blowing and drying the heat transfer pipe. When the drying pipe opening 102 is not in use, the drying pipe opening cover plate 105 is closed to protect the drying pipe opening 102 and prevent foreign matter from entering.

[0029] The utility model discloses an embodiment provides a manhole anti-foreign cover plate, manhole anti-foreign cover plate includes manhole protection surface, and manhole protection surface includes the center part and the edge part of being connected, and the center part is provided with drying pipe mouth and at least two observation holes, and the edge part is provided with a plurality of mounting holes, and drying pipe mouth is used for drying air pipe to enter and fixed, and mounting hole is used for the fixed of manhole protection surface and manhole sealing surface, drying pipe mouth cover plate, drying pipe mouth cover plate overturns relative to manhole protection surface, and is used for drying pipe mouth's opening or close. Through manhole anti-foreign cover plate setting drying pipe mouth, improve the sealing property and purging effect of drying pipe when heat transfer tube purging, and setting observation hole, the convenience of pipe plate state monitoring and monitoring camera cable passes through, improve the anti-foreign effect and on-site operation convenience.

[0030] Optionally, with reference to Figure 1 and Figure 2 , the thickness of the center part 1011 is less than the thickness of the edge part 1012. In the process of forming the manhole protection surface 101, the center part 1011 and the edge part 1012 are designed differently. The manhole anti-foreign cover plate 100 is circular, the center part 1011 is circular, and the edge part 1012 is annular. The thickness of the center part 1011 is less than the thickness of the edge part 1012. The thickness of the center part 1011 is about 3mm, and the thickness of the edge part 1012 is about 5mm. The center part 1011 is recessed relative to the edge part 1012. The thickness of the edge part 1012 is large, so that the drying pipe mouth 102 plays a certain internal and external isolation role during the heat transfer tube drying process, preventing foreign matter from entering the water chamber.

[0031] Optionally, with reference to Figure 1 and Figure 2 , the drying pipe mouth 102 can be selected to be arranged at the center of the center part 1011. This reduces the design difficulty of the manhole anti-foreign cover plate 100. By arranging the drying pipe mouth 102 at the center of the center part 1011, i.e., at the center of the circle of the center part 1011, the design is simple, the drying air pipe is convenient to enter and fix, and the on-site installation is convenient. At the same time, radiation is prevented from overflowing to the outside of the manhole anti-foreign cover plate 100.

[0032] Optionally, with reference to Figure 1, the drying pipe port cover plate 105 is connected with the center part 1011 through a hinge. Specifically, in the embodiment, the drying pipe port cover plate 105 is fixedly connected with the center part 1011 of the manhole protection surface 101 through a hinge, and meanwhile the drying pipe port cover plate 105 can be flipped relative to the manhole protection surface 101. The size of the drying pipe port cover plate 105 is slightly larger than the size of the drying pipe port 102. When the drying pipe port 102 is in an unused state, the drying pipe port cover plate 105 can shield the drying pipe port 102 to avoid foreign matters from entering the drying pipe port 102. When the drying pipe port 102 is in a used state, the drying pipe port cover plate 105 can be flipped open, so as to facilitate the drying air pipe to penetrate into the drying pipe port 102 to perform heat transfer tube purging and drying.

[0033] Optionally, with reference to Figure 1 and Figure 2 , the aperture of the drying pipe port 102 is the same as the aperture of the drying air pipe. The drying pipe port 102 is circular, the cross-sectional shape of the drying air pipe is circular, and the aperture of the drying pipe port 102 is consistent with the aperture of the drying air pipe in size, so that the drying air pipe can penetrate into the drying pipe port 102 without the need of a fixing structure to achieve fixation. Meanwhile, since the aperture of the drying pipe port 102 is the same as the aperture of the drying air pipe, it can be avoided that a gap appears between the drying pipe port 102 and the drying air pipe during the heat transfer tube purging and drying process of the drying air pipe, so as to achieve shielding of boron water splashing and loose pollutants, and also to prevent foreign matters from invading the interior of the water chamber during the heat transfer tube purging and drying process.

[0034] Optionally, with reference to Figure 1 and Figure 2 , the at least two observation holes 103 include a first observation hole 1031 and a second observation hole 1032, and the first observation hole 1031 and the second observation hole 1032 are symmetrically arranged about the drying pipe port 102. By arranging multiple observation holes 103, such as the first observation hole 1031 and the second observation hole 1032, the condition of the water chamber and the tube plate can be observed, and a monitoring camera cable can be penetrated, so as to ensure real-time observation of the purging and drying condition of the heat transfer tube. The first observation hole 1031 and the second observation hole 1032 are symmetrically arranged about the drying pipe port 102, so that the purging and drying condition of the heat transfer tube at different positions can be observed. When the observation hole 103 is in a non-used state, an on-site foreign matter prevention adhesive tape can be used for sealing, so as to prevent foreign matters from entering the water chamber through the observation hole 103, which is convenient and fast.

[0035] Optionally, with reference to Figure 1 and Figure 2The shape of the observation hole 103 is oval or circular. The shape of the observation hole 103 can be selected according to actual design requirements. Preferably, the shape of the observation hole 103 is oval, which facilitates real-time observation of the blowing and drying of the heat transfer pipe.

[0036] Optionally, with reference to Figure 1 and Figure 2 The manhole protection surface 101 is connected to the manhole sealing surface by bolts. Specifically, in the embodiment, the manhole protection surface 101 is circular, and the manhole sealing surface is also circular. The mounting holes 104 are uniformly distributed in the circumferential direction of the manhole protection surface 101. The mounting holes 104 are through holes, and the bolts are screwed into the threaded holes on the manhole sealing surface through the mounting holes 104, thereby achieving detachable connection of the manhole protection surface 101 and the manhole sealing surface. The bolt connection not only has good connection properties, but also is easy to disassemble. The manhole protection surface 101 and the manhole sealing surface can be quickly and fixedly connected, reducing the splashing of boron water and the overflow of loose pollutants.

[0037] Optionally, with reference to Figure 1 and Figure 2 The plurality of mounting holes 104 include a first mounting hole 1041, a second mounting hole 1042, a third mounting hole 1043, and a fourth mounting hole 1044. The first mounting hole 1041 and the second mounting hole 1042 are symmetrically arranged about the drying pipe opening 102, and the third mounting hole 1043 and the fourth mounting hole 1044 are symmetrically arranged about the drying pipe opening 102. Specifically, for example, four mounting holes 104 are provided, as shown in Figure 1 The first mounting hole 1041, the second mounting hole 1042, the third mounting hole 1043, and the fourth mounting hole 1044 are uniformly arranged in the circumferential direction, or they can also be arranged in a rectangular shape. The four mounting holes 104 are located at the four vertices of the rectangle. By providing a plurality of mounting holes 104, the fixed connection effect of the manhole protection surface 101 and the manhole sealing surface is ensured, and the foreign matter prevention effect is improved.

[0038] Optionally, a separation pad is arranged between the edge portion 1012 of the manhole protection surface 101 and the manhole sealing surface. The separation pad can be a rubber pad, which is relatively soft and ensures the fixed connection effect between the manhole protection surface 101 and the manhole sealing surface, avoiding damage to the manhole sealing surface. The separation pad can have the same shape as the edge portion 1012 of the manhole protection surface 101, i.e., a circular ring shape. Alternatively, the separation pad can include a plurality of separation portions, each corresponding in number to a mounting hole 104. The separation pad can be arranged around the mounting hole 104 to avoid damage to the manhole sealing surface by the bolts when the manhole protection surface 101 and the manhole sealing surface are fixedly connected through the mounting holes 104, ensuring the fixed connection effect and thereby reducing the splashing of boron water and the overflow of loose pollutants.

[0039] The above detailed description does not constitute a limitation on the protection scope of the present application. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution, and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A manhole cover for preventing foreign matter, characterized by comprising: The manhole anti-foreign cover plate comprises: A manhole protection surface comprising a center part and an edge part, the center part being connected with the edge part, the center part being provided with a drying pipe opening and at least two observation holes, the edge part being provided with a plurality of mounting holes, the drying pipe opening being used for the penetration and fixation of a drying air pipe, and the mounting holes being used for the fixation of the manhole protection surface and a manhole sealing surface; A drying pipe opening cover plate being flipped relative to the manhole protection surface and being used for the opening or closing of the drying pipe opening.

2. The manhole cover of claim 1, wherein, The thickness of the center part is less than the thickness of the edge part.

3. The manhole cover of claim 1, wherein, The drying pipe opening is arranged at the center of the center part.

4. The manhole cover of claim 1, wherein, The drying pipe opening cover plate is connected with the center part through a hinge.

5. The manhole cover of claim 1, wherein, The aperture of the drying pipe opening is the same as the aperture of the drying air pipe.

6. The manhole cover of claim 1, wherein, The at least two observation holes comprise a first observation hole and a second observation hole, the first observation hole and the second observation hole being symmetrically arranged about the drying pipe opening.

7. The manhole cover of claim 1, wherein, The observation holes are in the shape of an ellipse or a circle.

8. The manhole cover of claim 1, wherein, The manhole protection surface and the manhole sealing surface are connected through bolts.

9. The manhole cover of claim 1, wherein, The plurality of mounting holes comprise a first mounting hole, a second mounting hole, a third mounting hole and a fourth mounting hole, the first mounting hole and the second mounting hole being symmetrically arranged about the drying pipe opening, and the third mounting hole and the fourth mounting hole being symmetrically arranged about the drying pipe opening.

10. The manhole cover of claim 1, wherein, An isolation pad is arranged between the edge part of the manhole protection surface and the manhole sealing surface.

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