JP6241876B2 - Underground structure - Google Patents

Description

  The present invention relates to an underground structure that connects a sewer pipe and the like to the ground.

In the manhole connecting the sewer and the ground, the opening on the ground is closed with a lid to prevent people and objects from falling or odors from leaking. Normally, a drainage hole is formed in the lid so that the lid does not scatter due to the pressure in the sewer line.
However, when a large amount of rainwater flows into the sewer pipe at a stretch, if the pressure in the sewer pipe rises rapidly, it is not possible to cope with such a pressure rise only with the exhaust pressure hole formed in the lid. .
Therefore, manholes with through-holes for releasing air in addition to the exhaust holes formed in the lid are assumed to increase the exhaust pressure so that the pressure that has suddenly increased in the sewer line can be released sufficiently. A lid structure is known (Patent Document 1).

The one described in Patent Document 1 is provided with a receiving frame for receiving a hole cover at the upper end of a manhole, and a ventilation groove is formed by a receiving frame inner side wall, a receiving frame outer wall, and a ventilation groove bottom part on which the hole opening cover is placed. In addition, a ventilation lid provided with a large number of through holes is placed on the upper part of the ventilation groove, and a swing plate is provided in a plurality of ventilation holes formed in the inner side wall of the receiving frame.
Normally, the swinging plate blocks the vent, but when the air pressure in the manhole rises rapidly, the swinging plate opens outward and the vent is opened, and the pressure in the sewer pipe is It escapes to the outside from the exhaust hole of the through hole and the entrance lid.

Japanese Patent No. 4759169

In the manhole cover structure disclosed in Patent Document 1, if mud or dust accumulates at the bottom of the ventilation groove, the rocking plate is prevented from swinging outward, and cannot perform the exhaust pressure function through the vent.
The problem to be solved by the present invention is that air can be sufficiently released when the pressure in the cylindrical space suddenly rises, and even if mud or dust accumulates below the annular portion provided with the vent hole, The purpose is to provide an underground structure that maintains its function.

The present invention relates to a ground structure that opens to the ground and forms a cylindrical space in the ground, and a lid having air permeability is fitted into a lid support frame installed in the ground opening, and a space is provided below the lid. An inner lid with an air valve for blocking odor is installed, and the lid support frame has an annular portion along the ground surface, and a vent hole is formed in the annular portion, and the lid and the inner lid The space between and the lower surface side of the annular portion communicate with each other.
The inner lid is placed so as to be able to lift on a support surface provided on a wall surface constituting the cylindrical space, and floats when the pressure from below is high, so that the air flow between the inner cover and the support surface It may be a structure that creates a gap.
The inner lid may have a structure having a peripheral wall inclined so that the diameter gradually increases toward the upper end.

According to the present invention, since the vent hole is formed in the annular portion of the lid support frame outside the breathable lid, the opening area of the closed portion of the ground opening portion is widened, and suddenly in the cylindrical space. The increased pressure can be released sufficiently.
Since the air valve that opens when the pressure in the cylindrical space rises is provided on the inner lid installed below the lid, the operation of the air valve can be performed even if mud or debris dropped from the vent hole accumulates below the annular part. Not disturbed.

According to the second aspect of the present invention, when the pressure in the cylindrical space cannot be released to the upper side of the inner lid simply by opening the air valve, the pressure can be exhausted through the gap formed between the inner lid and the support surface. .
According to the third aspect of the present invention, the air blown upward of the inner lid is guided by the peripheral wall inclined so as to gradually increase in diameter toward the upper end of the inner lid and diffuses evenly below the annular portion. Therefore, it exhausts efficiently from all the vent holes. When the inner lid can be lifted, the air is guided by the peripheral wall inclined so that the diameter gradually increases toward the upper end below the inner lid, and the movement of the air blowing up the peripheral wall becomes uniform. Can be evenly raised, and the annular gap formed between the inner lid and the support surface can be increased.

It is a disassembled perspective view which shows the Example of this invention. It is sectional drawing in the normal state which shows the Example of this invention. It is a top view which shows the Example of this invention. It is sectional drawing in the damper open state in the Example of this invention. It is sectional drawing in the air valve open state in the Example of this invention. It is sectional drawing in the state where the inner lid floats in the Example of this invention. It is sectional drawing in the normal state which shows the other Example of this invention. The top view of the inner cover in the other Example of this invention. It is sectional drawing in the normal state which shows the other Example of this invention.

Hereinafter, an embodiment in which the ground structure is a manhole connecting the sewer pipe line and the ground will be described.
As shown in FIGS. 1 and 2, the manhole 1 is composed of a rising tube 2, a lid 3, an inner lid 4, and a lid support frame 5.
The riser pipe 2 is buried in the ground to form a cylindrical space 6 therein. The lower end of the start-up pipe 2 leads to the sewer pipe, and the upper end opens to the ground. A plurality of anchor bolts 28 and guide bolts 33 are provided at the upper end of the rising pipe 2 at equal intervals in the circumferential direction and shifted in position.
The lid 3 is a member that closes the ground opening of the manhole 1 and is made of a cast iron disk. The lid 3 has a number of exhaust holes 7 and a plurality of clamp protrusions 8 attached at equal intervals in the circumferential direction. The total area of the exhaust holes 7 is about 40% of the area of the ground opening of the manhole 1 in this embodiment. The clamp protrusion 8 is suspended below the lid 3 via a bolt 9 penetrating the radial long hole of the lid 3, and can be moved in the radial direction by loosening the bolt 9.

The inner lid 4 is installed below the lid 3 with an interval, and has an inverted conical peripheral wall 10 inclined so as to gradually increase in diameter toward the upper end, and a flange 11 projecting outward from the upper end of the peripheral wall 10; A bottom plate 12 provided at the lower end of the peripheral wall 10 and a damper 13 attached to the bottom plate 12 are provided, and as described above, the entire shape is an inverted cone.
Exhaust ports 14 that communicate the space between the lid 3 and the inner lid 4 and the cylindrical space 6 are provided at a plurality of locations on the peripheral wall 10. The exhaust port 14 is normally closed and opened and closed by a flap type air valve 15 that is opened by a pressure increase on the cylindrical space 6 side.
A plurality of guide bolt insertion holes 22 are formed in the flange 11 at equal intervals in the circumferential direction.
The bottom plate 12 is inclined to one side (FIG. 2), and an opening 16 is formed on the lower side of the bottom plate 12 (left side in FIG. 2). An end of the bottom plate 12 facing the opening 16 is bent downward at a right angle to form a blocking edge 17.

The damper 13 includes a plate 18 that opens and closes the opening 16 of the bottom plate 12, a weight 19 that is fixed to the plate 18, and a magnet 20 that attracts the plate 18 in the closing direction.
One end of the plate 18 is attached to the lower surface of the bottom plate 12 via a hinge 21 at a position slightly higher than the blocking edge 17. The weight 19 is fixed to one end of the plate body 18, and the magnet 20 is fixed to the lower end portion of the peripheral wall 10 on the side opposite to the blocking edge 17 across the opening 16. The plate 18 that rotates about the hinge 21 is normally brought into contact with the lower end of the peripheral wall 10 and the blocking edge 17 by the attracting force of the magnet 20 and the weight 19 and stopped in a state where the opening 16 is closed. (Fig. 2).

The lid support frame 5 has an annular upper wall 24 connecting the outer annular wall 23a and the inner annular wall 23b, an upper edge of the outer annular wall 23a and an upper edge of the inner annular wall 23b, and a lower edge of the inner annular wall 23b from the lower edge to the center. An overhanging lid flange 26 and a support flange 25 overhanging substantially horizontally from the lower edge of the outer annular wall 23a are provided. An inner diameter of the inner annular wall 23b is substantially the same as an inner diameter of the upper flange 2a of the rising pipe 2. An annular window 31a is provided between the lid flange 26 and the support flange 25. By this annular window 31a, the space of the annular groove 31b formed by the outer annular wall 23a, the inner annular wall 23b and the annular upper wall 24 is communicated with the space inside the rising pipe 2. The communicated space communicates with the outer space of the manhole 1 through a large number of vent holes 27 (FIG. 3) provided radially on the annular upper wall 24.
The total area of the vent holes 27 is set to be about 40% of the area of the ground opening of the manhole 1. In order to form the vent hole 27 having a sufficient area, it is desirable that the annular upper wall 24 has a width of 80 mm or more (outer spacing between the outer annular wall 23a and the inner annular wall 23b).

  A plurality of through holes 29 for passing anchor bolts 28 (FIG. 2) and through holes 30 for passing guide bolts 33 are formed in the support flange 25. The through hole 30 for passing the guide bolt 33 is formed inside the through hole 29 for passing the anchor bolt 28. Further, the through hole 30 for passing the guide bolt 33 corresponds to the position of the guide bolt insertion hole 22 of the inner lid 4 and is shifted in the circumferential direction from the through hole 29 for passing the anchor bolt 28. Is formed.

To construct the manhole 1, as shown in FIG. 2, the lid support frame 5 is passed through the upper end of the rising pipe 2 buried in the ground, the through hole 29 is passed through the anchor bolt 28, and the through hole 30 is guided. The support flange 25 is fixed by the anchor bolt 28 and the nut 32, and the annular upper wall 24 is disposed along the ground surface (on the same plane as the ground surface). The guide bolt 33 is protruded upward through the through hole 30.
Next, the flange 11 of the inner lid 4 is placed on the support flange 25 of the lid support frame 5, and the guide bolt insertion hole 22 of the inner lid 4 is protruded upward from the through hole 30 of the support flange 25 in the lid support frame 5. The inner lid 4 is attached to the lid support frame 5 through the bolts 33. The length of the shaft portion of the guide bolt 33 is longer than the sum of the thickness of the support flange 25 and the thickness of the flange 11 of the inner lid 4, and the through hole 30 of the support flange 25 is sufficiently larger than the shaft portion diameter of the guide bolt 33. The inner lid 4 can be lifted from the upper surface of the support flange 25 which is the support surface. In addition, it is preferable to attach a nut etc. to the upper end part of the guide bolt 33, and to make it the structure which can suppress that the inner lid | cover 4 lifts too much.

Next, the lid 3 is fitted inside the lid support frame 5 with the clamp projection 8 moved inward, the lid 3 is placed on the lid flange 26 of the annular portion 24, and then the clamp projection 8 is moved outward. Move to and fix. The clamp protrusion 8 moved outward is inserted into the groove 31 b of the lid support frame 5 and engaged with the lower surface of the lid hooking flange 26.
Thus, when the lid 3 and the inner lid 4 are installed with an interval in the vertical direction, the annular groove 31b between the annular upper wall 24 and the support flange 25 opens to the inner peripheral side through the annular window 31a. 3 and the inner lid 4 communicate with the outside of the manhole 1 through the vent hole 27 of the annular upper wall 24.

Normally, the exhaust port 14 and the opening 16 of the inner lid 4 are closed to prevent the bad odor generated in the sewer pipe from leaking outside through the cylindrical space 6. On the other hand, since the space between the lid 3 and the inner lid 4 and the outside air are connected by the exhaust hole 7 of the lid 3 and the vent hole 27 of the annular upper wall 24, the outside air and rainwater flow into the manhole 1. And if rainwater and mud more than fixed weight accumulate on the board 18 of the inner lid 4, the board 18 will open (FIG. 4).
When the pressure in the cylindrical space 6 becomes higher than the external atmospheric pressure, the air valve 15 is opened and the exhaust port 14 is opened (FIG. 5), and air rises from the cylindrical space 6 to the space between the lid 3 and the inner lid 4. Further, the air is exhausted from the exhaust hole 7 of the inner lid 4 and the vent hole 27 of the annular upper wall 24 to the outside of the manhole 1. Further, the air blown above the inner lid 4 is guided to the peripheral wall 10 and diffused evenly, enters the annular groove 31b through the annular window 31a, and is exhausted almost uniformly from the vent holes 27 of the annular upper wall 24. .

If the air pressure below the inner lid 4 suddenly increases due to sudden heavy rain and the like, and the pressure difference between the lower and upper sides of the inner lid 4 becomes large and exhaust from the exhaust port 14 alone is not sufficient, The flange 11 floats from the upper surface of the support flange 25 of the lid support frame 5 (FIG. 6). Then, since a gap is formed between the flange 11 and the support flange 25, the air pressure can be released upward through this gap. At this time, air from below is guided by the inverted conical peripheral wall 10 of the inner lid 4 and spreads and rises evenly in the circumferential direction. Since the gap between the flange 11 of the inner lid 4 and the support flange 25 in the lid support frame 5 is annular, the opening amount is large.
Further, since the opening ratio is only about 40% with the exhaust pressure hole 7 of the lid 3, a large amount of air flows into the space between the lid 3 and the inner lid 4 due to the increase of the pressure in the cylindrical space 6. When the pressure in the space increases, the pressure may not be released from the lid 3 and the lid 3 may jump. However, a vent hole 27 is formed in the annular upper wall 24 of the lid support frame 5, and the air inside the manhole is formed there. By adopting a structure for guiding the flow, the aperture ratio is about 50% to 80%, and the lid 3 can be prevented from jumping up.
On the other hand, if rainwater, mud or the like of a certain weight or more accumulates on the plate 18, the plate 18 can no longer maintain the closed state by the weight 19 and the magnet 20, and rainwater, mud, etc. that suddenly rotates and accumulates. Is dropped into the cylindrical space 6 (FIG. 4).

The detailed structure of the underground structure is not limited to the above embodiment. For example, the shape of the inner lid and the structure of the damper or air valve provided on the inner lid may be changed to a conventionally known one.
Note that the peripheral wall inclined so that its diameter gradually increases toward the upper end of the inner lid has an inverted conical shape in the description of the embodiments, but it is close to a frustoconical shape precisely. The basic shape is not limited to a cone, but may be a pyramid (polygonal pyramid).

7 to 8 show other embodiments of the manhole 1 and are characterized by the structure of the inner lid 4. Since the other structure is the same as that of the embodiment described above, only the structure of the inner lid 4 will be described with reference to the same reference numerals.
As shown in FIGS. 7 and 8, in this embodiment, the inner lid 4 has a structure of a parent-child lid provided with a core lid 34. The core lid 34 has a handle 35 on the upper surface side, and when the inside of the manhole 1 is inspected, the core lid 34 is opened to enter the inside. Since the core lid 34 is smaller than the middle lid 4, the core lid 34 is lightweight, and the burden on the operator is less than when the entire middle lid 4 is lifted. Some manhole iron covers are equivalent to parent-child covers, but not on the inner cover. The core lid 34 may be simply placed by covering the opening provided in the inner lid 4 so that it floats when the wind pressure from the cylindrical space 6 is high. Similarly to the case 4, the guide may be lifted by being guided by a guide provided on the upper surface of the inner lid 4.

FIG. 9 shows a structure in which the core lid 34 has the same structure as the previously described middle lid 4, and includes a plate body 36, a weight 37, and a magnet 38, so that the closed state is always maintained. Reference numeral 39 is a guide pin provided on the upper surface of the inner lid 4 and guides the floating of the core lid 34 when the wind pressure from the cylindrical space 6 is high.
In the case of this structure, when the core lid 34 is opened, there is an effort to remove the retaining pin (such as a nut attached to the tip of the pin) of the guide pin 39. The guide pin 39 may be attached by welding or screwing to the inner lid 4 or by an engagement structure.

DESCRIPTION OF SYMBOLS 1 Manhole 2 Startup pipe 2a Upper flange 3 Lid 4 Middle lid 5 Lid support frame 6 Cylindrical space 7 Pressure relief hole 8 Clamp protrusion 9 Bolt 10 Perimeter wall 11 Flange 12 Bottom plate 13 Damper 14 Exhaust port 15 Air valve 16 Opening part 17 Blocking Edge 18 Plate 19 Weight 20 Magnet 21 Hinge 22 Guide bolt insertion hole 23a Outer annular wall 23b Inner annular wall 24 Annular upper wall 25 Support flange 26 Covering flange 27 Vent hole 28 Anchor bolt 29 Through hole 30 Through hole 31a Annular window 31b Annular groove 32 Nut 33 Guide bolt 34 Core cover 35 Handle 36 Plate body 37 Weight 38 Magnet 39 Guide pin

Claims (2)

A ground structure that opens to the ground and forms a cylindrical space in the ground, and a lid having air permeability is fitted into a lid support frame installed in the ground opening, and a space is provided below the lid. A lid is installed,
The lid support frame has an annular upper wall along the ground surface, and a ventilation hole is formed in the annular upper wall, and the space between the lid and the inner lid communicates with the lower surface side of the annular upper wall. And
The inner lid is composed of a peripheral wall, a flange projecting outward from the upper end of the peripheral wall, and a bottom plate provided at the lower end of the peripheral wall,
The inner lid is supported by a support surface provided on a wall surface forming the cylindrical space by a flange, and the whole lid can be lifted by air pressure from below, and when the pressure from below is high An underground structure characterized in that a gap for air circulation is created between the flange and the support surface by lifting the flange from the support surface. Peripheral wall of the inner lid is inclined to gradually diameter toward the top end is large, according to claim 1, the gap for air circulation was characterized by work Rukoto between the support surface by floating Underground structure .