JP7603438B2 - Manhole protection device - Google Patents

Description

The present invention relates to the protection of manholes installed in the walls of structures such as storage tanks, towers, and tanks, and in particular to a protection device for protecting the inner surfaces of manholes from scratches and dirt.

When constructing structures such as storage tanks for oil, or when inspecting, repairing, or carrying out other internal work during maintenance, workers may enter the structure through a horizontal manhole installed in the wall of the structure (or in the side wall of a storage tank) to carry out their work. When doing so, the inside of the manhole, especially the lower part, may be scratched by the tools carried by the workers, or may become dirty with mud, paint, etc. on the workers' shoes or clothing.

For this reason, it has been common practice to perform protective work by fixing a rag or polymer sheet called protective sheet 100 to the lower inner surface of a manhole 110 to protect that surface, as shown in Figure 9 (A). The protective sheet 100 is usually fixed by attaching both ends of the protective sheet 100 to the inner surface of the manhole 110 with protective adhesive tape 120.

In addition, when a gasket surface 130 is formed on the flange portion around the manhole opening, in order to protect this gasket surface 130 as well, conventionally, as shown in FIG. 9B, a protective treatment was performed in which the gasket surface 130 around the manhole opening was covered with protective adhesive tape 140. Another method of protecting the gasket surface 130 was to place a previously used gasket on that part and secure it with adhesive tape, etc.

However, the above-mentioned protective work is time-consuming, and there are problems in that it takes time to remove the protective sheets and adhesive tape after protective work is completed and to restore the protected areas.

The first object of the present invention is to solve the above problems and provide a curing device that can cover at least a portion of the inner surface of a manhole and efficiently cure that portion.

In addition, when protecting the gasket surface with adhesive tape, there is a problem in that it takes a lot of time to apply the adhesive tape to the gasket surface without any gaps, and to remove the adhesive tape after protection and restore the gasket surface. The same problem occurs when covering the gasket surface with a used gasket, and in particular when the used gasket is contaminated with contaminants or other dust, there is a risk that the used gasket itself cannot be used. In addition, when protecting the gasket surface, it is common to protect the inner surface of the manhole at the same time, so protecting the two surfaces separately is considered to be disadvantageous in terms of work efficiency.

The second object of the present invention is to provide a curing device that can solve the above problems when curing a gasket surface and efficiently cure the gasket surface and the inner surface of a manhole.

The present invention was made in consideration of the fact that manholes used in many structures such as storage tanks are cylindrical and contain magnetic material, and a curing device according to one aspect of the present invention is characterized by having a curing mat that can be attached to at least a portion of the inner surface of the manhole by magnetic force. As a source of magnetic force, a bendable magnetic sheet may be used as a basic component of the curing mat, or a permanent magnet such as a neodymium magnet fixed to a portion of the curing mat may be used.

In addition, since workers move on the protective mat, it is preferable that the protective mat has cushioning properties. If a magnetic sheet is used, it is considered to have a protective material attached to at least one side of the magnetic sheet (usually the side that the worker comes into contact with).

In addition, a curing device according to another aspect of the present invention is characterized in that, in addition to the curing mat, it is equipped with a curing sheet that can be magnetically attached to the periphery of the manhole opening so as to cover the gasket surface around one of the openings of the manhole.

As with the curing mat, this curing sheet may use a bendable magnetic sheet as a basic component of the curing sheet as a source of magnetic force, or a permanent magnet such as a neodymium magnet fixed to a part of the curing sheet. It is also preferable that the curing sheet has cushioning properties.

It is preferable that the protective sheet can be detachably attached to the protective mat so that they can be used simultaneously.

Furthermore, since the protective mat or protective sheet is attached to the manhole by magnetic force, it is possible that it may come off for some reason, and since manhole protection often takes a long time, it is expected that the manhole opening will be opened and closed frequently. Therefore, it is preferable that the protective device according to the present invention further comprises a protective cover that is arranged to cover one opening of the manhole, and that is configured to tighten the opening and fix it to the cylindrical part of the manhole with a string body with a string fastener, also called a cord lock or cord stopper, provided at the opening of the protective cover.

A curing device equipped with the above-mentioned curing mat can achieve the first object of the present invention, and since it can be attached to the inner surface of the manhole by magnetic force, it can be easily installed even by those who have no curing skills.

The curing device according to the present invention is also equipped with a curing sheet that protects the gasket surface in addition to the curing mat, and this can also be attached to cover the gasket surface by magnetic force, making it possible to achieve the second object of the present invention mentioned above. In particular, if the curing sheet can be detachably attached to the curing mat, it becomes possible to install the curing sheet at the same time as installing the curing mat, improving work efficiency. On the other hand, the curing mat and the curing sheet can also be separated and used separately, so it is also possible to carry out only the curing work as needed.

Furthermore, when the above-mentioned protective cover is provided, the protective cover can be attached to the manhole without using adhesive tape by using a string body with a string fastener, which is particularly suitable for cases where the manhole opening is frequently opened and closed.

The protective mats, protective sheets and protective covers used in the protective equipment can be reused.

1A and 1B are perspective views showing a curing mat and a curing sheet of a curing apparatus according to the present invention, in which FIG. 1A shows the mat and the sheet separated from each other, and FIG. FIG. 2 is a front view showing the state in which the curing device of FIG. 1 is installed in a manhole. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. FIG. 2 is a front view showing a schematic view of a curing cover of the curing apparatus according to the present invention. FIG. 2 is a front side view showing a schematic view of a curing cover of the curing apparatus according to the present invention. FIG. 11 is a perspective view showing a curing mat in a curing apparatus according to another embodiment of the present invention. FIG. 11 is a perspective view showing a curing sheet in a curing apparatus according to another embodiment of the present invention. FIG. 11 is a perspective view showing a protective cover in a protective device according to another embodiment of the present invention. 1A and 1B are schematic diagrams showing conventional curing methods, in which (A) shows curing of the inner surface of a manhole and (B) shows curing of a gasket surface.

Below, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings. Note that the same or equivalent parts are given the same reference numerals throughout the drawings, and duplicate explanations will be omitted.

Figure 1 shows one embodiment of a manhole protection device according to the present invention. In this embodiment, the protection device 10 is applied to a horizontal manhole 110 installed in the side wall 200 of a storage tank for oil or the like, as shown in Figures 2 and 3, and the manhole 110 is cylindrical and contains a magnetic material.

As shown in FIG. 1A, the curing device 10 is composed of a rectangular plate-shaped curing mat 20 and an annular curing sheet 30. As can be seen from FIG. 2 and FIG. 3, the curing mat 20 in this embodiment is placed on the lower inner surface of the cylindrical part of the manhole 110, and the curing sheet 30 is for protecting the annular gasket surface 130 formed on the flange part surrounding the opening of the manhole 110.

The curing mat 20 is composed of a magnetic sheet 22. The magnetic sheet 22 is a magnetic sheet obtained by applying a magnetic force to a thin magnetic material, and is flexible and can be curved into a cylindrical shape. In addition, it is preferable that at least one surface of the magnetic sheet 22 (the upper surface in FIG. 1, the surface that the worker comes into contact with) is provided with a protective material 24 having cushioning properties. The protective material 24 is preferably configured by sandwiching a sheet material such as a polyethylene foam sheet of an appropriate thickness (for example, Minafoam (registered trademark) with a thickness of 10 mm manufactured and sold by Sakai Chemical Industry Co., Ltd.) between two appropriate surface materials, but is not limited to this. In the case of a manhole 110 in a storage tank, since a worker crawls through the manhole 110, providing a protective material 24 is effective in supporting the weight of the worker and protecting his knees and hands, thereby obtaining a comfortable working environment. In addition, a tarpaulin with excellent durability, stain resistance, and water resistance is effective as the surface material of the protective material 24.

There are various possible dimensions for the curing mat 20, but in order to cover the area through which workers pass, it is preferable that the short side D1 has a length equal to the overall length of the manhole 110, and the long side D2 has a length equal to the arc length of the inner surface of the lower half of the manhole 110, i.e., "the inner diameter of the manhole x π ÷ 2".

The curing sheet 30 is also composed of a magnetic sheet 32, similar to the curing mat 20. It is preferable that the curing sheet 30 has a protective material 34 similar to that of the curing mat 20 on at least one side (the side that is visible in FIG. 1 and exposed to the outside) to reduce the impact when a worker touches the curing sheet 30, but since the sheet is rarely touched by workers, it may be thinner than the curing mat 20. The protective material 34 is preferably composed of a polyethylene foam sheet of an appropriate thickness, for example, a 2 mm thick sheet material with cushioning properties such as Belpollen or Minafoam (registered trademark) sandwiched between two appropriate surface materials such as tarpaulin, but is not limited to this.

The dimensions of the protective sheet 30 need only be sufficient to cover the gasket surface 130 of the manhole 110, so the inner diameter of the protective sheet 30 needs only to be equal to the inner diameter of the gasket surface 130, which is essentially the inner diameter of the opening of the manhole 110, and the outer diameter of the protective sheet 30 needs only to be equal to the outer diameter of the gasket surface 130.

Since it is preferable to use the curing mat 20 and the curing sheet 30 simultaneously during the curing work, it is effective to have them connected as shown in (B) of FIG. 1. Various means can be considered as a means of connection, such as being integrated in an inseparable manner, but in this embodiment, they are connected in a separable manner. That is, an ear portion 26 is formed in the center of one side edge portion of the curing mat 20, and this ear portion 26 can be passed through the center hole of the curing sheet 30 and folded to abut against a part of the curing sheet 30. In addition, one side of a hook-and-loop fastener known as Velcro (registered trademark) (not shown) is provided on the folded side surface of the ear portion 26, and the other side of the hook-and-loop fastener 36 is provided on the surface of the curing sheet 30 that receives the ear portion 26, and by abutting these, the curing mat 20 and the curing sheet 30 are connected in a separable manner. It is not necessary to make them separable, but it is effective because only one of the curing mat 20 and the curing sheet 30 may be sufficient depending on the type of curing work. For example, although not shown, it is possible to use only the protective sheet 30 when it is necessary to protect the gasket surface of a manhole cover.

The ears 26 can also be used as gripping pieces to make handling of the curing mat 20, especially removal, easier. They also serve as a marker to indicate that curing remains if an attempt is made to close the manhole 110 with a manhole cover. For the same purpose, it is preferable to form ears 38 on the curing sheet 30.

When using such a curing device 10, when the two ends of the short side of the curing mat 20 are brought closer together from the state shown in FIG. 1B, the curing mat 20 is curved and its cross section becomes roughly semicircular. In this state, the side edge of the curing mat 20 opposite the ears 26, 38 is inserted through the opening of the manhole 110 and pushed in until the curing sheet 30 contacts the flange part of the manhole 110 on which the gasket surface 130 is formed. Because the curing mat 20 has self-restoring properties due to the nature of its material, simply removing the force applied thereto causes the entire magnetic sheet 22 of the curing mat 20 to abut against the lower inner surface of the manhole 110 as shown in FIG. 2 and FIG. 3. Because the manhole 110 contains a magnetic material, the magnetic sheet 22 of the curing mat 20 adheres tightly to the manhole 110 due to magnetic force. In addition, the protective sheet 30 has its magnetic sheet 32 that comes into contact with the surface of the flange of the manhole 110 and adheres to it by magnetic force, covering and protecting the gasket surface 130.

In this way, the curing device 10 according to this embodiment can be attached to the manhole 110 by magnetic force, so that the installation can be completed easily without using adhesive tape as in the past. This work does not require any special skills, and even inexperienced workers can fully carry out the desired curing work. When the curing device 10 is installed, workers can enter and exit through the central hole of the curing sheet 30 and move back and forth on the curing mat 20, but the surface of the manhole 110 under the curing mat 20 and the curing sheet 30 is not scratched or stained at that time, and even if the worker comes into contact with the curing mat 20 and the curing sheet 30, the protective materials 24, 34 protect the worker, making it possible to perform maintenance and other work comfortably. In addition, even if the curing mat 20 and the curing sheet 30 are relatively thin, they are in close contact with the contact surface with the manhole 110, so there is no risk of wrinkles.

When maintenance work on the storage tank is completed and the manhole 110 no longer needs to be protected, the protection device 10 can be removed from the manhole 110 by pulling the ears 26, 38 with enough force to overcome the magnetic force of the magnetic sheets 22, 32. This removal work is much easier than the conventional work of peeling off adhesive tape, and there is no need to remove the adhesive remaining on the manhole 110 after peeling off the adhesive tape. In addition, since the protection mat 20 and the protection sheet 30 can be separated, for example, when restoring the gasket surface 130, it is possible to remove only the protection sheet 30, and when restoring the inner surface of the manhole 110, it is possible to remove only the protection mat 20.

Furthermore, the protective mat 20 and protective sheet 30 that are removed after curing can be reused because they are not attached with adhesive tape or the like.

Meanwhile, maintenance work on storage tanks often takes a long time, and in such cases, traditionally the protective sheet on the inside of the manhole and the adhesive tape on the gasket surface would be left on the manhole as is, and instead of using a manhole cover, the manhole opening would be temporarily closed with a protective cover as a fireproof and waterproofing measure. Conventional protective covers are made of a fireproof and waterproof sheet material such as tarpaulin, which is placed over the manhole opening, and the free edge of the protective cover is gathered together with the cylindrical part of the manhole and secured in place with adhesive tape or rope, etc.

However, when performing maintenance or other work, the protective cover must be removed each time, and once the work is completed, the protective cover must be reinstalled. Reinstalling the protective cover is time-consuming, and there is a risk of gaps occurring when securing the cover with adhesive tape or rope. Furthermore, when the protective cover is secured with adhesive tape, it is often difficult to reuse the cover.

On the other hand, in the case of the curing device 10 according to the present invention, the curing mat 20 and curing sheet 30 can be easily removed, so the curing cover is important to prevent the curing mat 20, etc. from accidentally falling off.

Therefore, we have invented a new curing cover 40 as shown in Figures 4 and 5 as an optional component of the curing device 10.

The protective cover 40 according to one embodiment of the present invention is made of a flexible sheet material suitable for fireproofing and waterproofing, such as tarpaulin, as in the conventional case, and is configured in a bag shape so as to cover the entire flange of the manhole 110. A string passage part 42 is formed at the periphery of the mouth of the protective cover 40, and a single string 44 is passed through it in a loop shape. An ester round rubber string with a diameter of about 4 mm is suitable as the string 44, and by pulling both ends of this string 44, the mouth of the protective cover 40 can be elastically tightened in a drawstring shape. Both ends of the string 44 are passed through a string fastener 46 generally called a cord stopper or cord lock (for example, a cord lock (CL2-T) manufactured and sold by Nifco Co., Ltd.), and the tightening of the mouth of the protective cover 40 can be easily and quickly adjusted by this string fastener 46. Conventional methods of fastening the protective cover with adhesive tape or rope tended to result in gaps between the protective cover and the manhole, but the protective cover 40 of this embodiment can increase the degree of sealing between the cover and the manhole 110, improving fire resistance and waterproofing. It also reduces or prevents gas from escaping from inside the storage tank to the outside, improving safety.

In addition, a window 48 is formed on the main surface of the protective cover 40, which can be opened and closed airtightly by a fastener (for example, a plastic fastener with two slats and a head joint). A gas hose 50 or the like can be installed through this window 48, and it is used to discharge residual gas and odors inside the storage tank to the outside and to maintain an atmosphere of nitrogen or the like. Conventional protective covers were not intended to be reused, so such a window was not provided, but according to the present invention, the protective cover 40 is also reused, so the window 48 is provided, making it possible to discharge residual gas, etc., and also providing a simple access means for other work. The reference numeral 54 in Figs. 4 and 5 denotes a rain cover that prevents rainwater from entering through a gap that occurs when the gas hose 50 is inserted through the fastener of the window 48.

In addition, since the main surface of the protective cover 40 is widely exposed, for example, the part indicated by the reference numeral 52 in FIG. 4 can be used as a display section for displaying work precautions, etc.

The above describes in detail a preferred embodiment of the present invention, but it goes without saying that the present invention is not limited to the above embodiment.

For example, the curing mat 20 shown in Figures 1 to 3 has a main body made of a magnet sheet 22, and although a magnetic force is generated over almost the entire surface of the curing mat 20, a configuration in which a magnetic force is generated partially is also possible. For example, small magnet sheets may be arranged in a dispersed manner over the entire curing mat 20, or multiple (three in the illustrated embodiment) disk-shaped permanent magnets 60 may be fixed to each end of the curing mat 20 as shown in Figure 6. As the permanent magnets 60, for example, neogeo magnets with strong magnetic force are preferable. The main body of the curing mat 20 shown in Figure 6 may be made of the same structure as the protective material of the curing mat 20 shown in Figures 1 to 3, but is not limited to this. In the case of the curing mat 20 configured as shown in Figure 6, if the permanent magnets 60 are kept away from the inner surface of the manhole 110, the curing mat 20 can be moved without being affected by the magnetic force, making it easier to install the curing mat 20.

The protective sheet 30 that protects the gasket surface 130 shown in Figures 1 to 3 is an annular, indivisible, one-piece type, but it may be divisible. For example, as shown in Figure 7, multiple arc-shaped protective sheet segments 70 may be arranged in a ring shape, with the ends of adjacent protective sheet segments 70 detachably joined together by hook-and-loop fasteners 72a, 72b. Making the protective sheet 30 divisible in this way makes it easier to handle, such as by attaching and removing the protective sheet 30. Of course, it is also possible to make the protective mat 20 divisible as well.

In the case of the curing sheet 30 shown in FIG. 7, each curing sheet segment 70 is made by sandwiching a cushioned sheet material 70c such as Belpollen or Minafoam (registered trademark) between two surface materials 70a, 70b such as tarpaulin, and joining the surface materials 70a, 70b by sewing or the like along the periphery of the sheet material 70c. When the surface materials 70a, 70b are shifted in the circumferential direction during the production of the curing sheet segment 70, and hook-and-loop fasteners 72a, 72b are provided at the shifted portions, the surface of the joint is less uneven when joined to the adjacent curing sheet segment 70, making it less likely for workers' clothes to get caught or for dirt to get in.

The magnetic source in the curing sheet 30 shown in FIG. 7 is a disk-shaped permanent magnet 74, such as a neodymium magnet, as in the curing mat 20 in FIG. 6. The permanent magnet 74 can be installed by embedding it in a recess or through hole 76 provided in the sheet material 70c, but is not limited to this.

The protective cover 40 shown in Figs. 4 and 5 is made of a flexible sheet material such as tarpaulin in a bag shape, but as in the protective cover 40 shown in Fig. 8, the portions 80, 82 surrounding the flange portion of the manhole 110 may be made to have a certain degree of rigidity. In the case of a rigid protective cover 40, the cover itself does not twist or bend, making installation very easy. In addition, a polyester flame-retardant twill 84, such as F2600 Ernest sold by Aotake Co., Ltd., extends in a skirt shape from the free edge of the cylindrical portion 82 of the protective cover 40. The opening of this twill 84 is provided with a string 44 with a fastener 46, as in the protective cover 40 shown in Figs. 4 and 5, making it easy to attach the protective cover 40 to the manhole 110 and adjust its position.

In addition, for example, in the above embodiment, the curing mat 20 is fixed only to the lower inner surface of the manhole 110, but it is also possible to extend the entire length of the curing mat 20 so that it covers the entire circumference of the inner surface of the manhole 110.

Furthermore, the present invention is not limited to the manhole 110 of an oil storage tank, but can also be applied to manholes or equivalents of other buildings. For example, in a building having multiple compartments such as a nuclear reactor building, the present invention can be applied to the equivalent of a manhole to a pipe that penetrates the wall separating the compartments, as long as it is cylindrical and contains a magnetic material. The manholes to which the present invention can be applied are not limited to horizontal types, and since the curing mat 20 and/or curing sheet 30 in the curing device 10 of the present invention can be attached by magnetic force, the present invention can also be applied to vertical manholes that extend vertically.

LIST OF SYMBOLS 10...Curing device, 20...Curing mat, 22...Magnetic sheet of curing mat, 24...Protective material of curing mat, 26...Ear of curing mat, 30...Curing sheet, 32...Magnetic sheet of curing sheet, 34...Protective material of curing sheet, 36...Velcro, 38...Ear of curing sheet, 40...Curing cover, 42...String passage, 44...String body, 46...String fastener, 48...Window, 50 ...Gas hose, 52...Display unit, 54...Rain cover, 60...(Disc-shaped) permanent magnet, 70...Protection sheet segment, 70a, 70b...Surface material, 70c...Sheet material, 74...(Disc-shaped) permanent magnet, 76...Recess or through hole, 80, 82...Rigid part of protective cover, 84...Twill, 110...Manhole, 130...Gasket surface, 200...Side wall of storage tank (wall of building)

Claims (3)

A covering device for use in a manhole including a magnetic material installed through a side wall of a building,
A curing device for a manhole, comprising a curing mat that is attached to at least a portion of the inner surface of the manhole by magnetic force in a curved state that follows the curved shape of the manhole . 2. The manhole protection device according to claim 1, further comprising an annular protection sheet that is attached to the periphery of one of the openings of the manhole by magnetic force so as to cover the gasket surface around the opening of the manhole. The manhole curing device according to claim 1 or 2, which is provided with a curing cover arranged to cover one opening of the manhole, and which is configured to be fixed to the cylindrical portion of the manhole by tightening the opening with a string body with a string fastener provided at the opening of the curing cover.

Images