JP2017025582A - Backflow prevention device for underground structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a backflow prevention device for an underground structure, the device that can prevent back blow in the conduit of an underground structure without a restriction of an installation location and without using a flexible elastic member of a complex and special shape as a check valve body.SOLUTION: A flexible elastic board 10 having flexibility and elasticity and having a substantially rectangular shape when expanded is used as a check valve body. This flexible elastic board 10 is disposed so that one side 12 of the downstream side in the flow direction of a conduit 20 of an underground structure may conform in an inner circumferential surface of the lower side of the conduit 20. Also, the flexible elastic board functions as a check valve body by that two sides of 13, 13 along the flow direction of the conduit are fixed to the inner circumferential surface of the conduit 20, and one side 11 of the upstream side in the flow direction of the conduit is fixed to the inner circumferential surface of the upper side of the conduit 20.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a backflow prevention device for an underground structure installed in a pipeline of the underground structure.

  As a pipeline of an underground structure where a backflow prevention device is installed, a pipeline for discharging sewage treated water or rainwater to a river or the sea can be mentioned. In such pipelines, a backflow prevention device is installed to prevent backflow from rivers and the sea, especially when storm surges and tsunamis occur. Generally, a backflow prevention device is installed at the end of the pipeline. A flap valve is installed (for example, Patent Document 1).

  However, the backflow prevention device using a flap valve has a problem in durability because it requires a mechanical movable mechanism, and it is difficult to install it at a place other than the end of the pipe line, so the installation place is limited. There is a problem that there is.

  On the other hand, a device using a check valve body is known as a general pipe backflow prevention device. Patent Documents 2 and 3 disclose flexibility and elasticity as the check valve body. A backflow prevention device using a flexible elastic member is proposed. If a flexible elastic member is used as the check valve body in this way, the mechanical movable mechanism can be eliminated, so that the problem of durability can be solved, and the check valve body is located downstream of the manhole. Since it can be installed in places other than the end of the pipeline, such as in the middle of the (outflow pipe) or the pipeline, the problem of the installation location can also be solved.

  However, in the backflow prevention devices of Patent Documents 2 and 3, the shape of the flexible elastic member is complicated and special in order to exhibit the function as a check valve body. It is necessary to prepare a flexible elastic member. For example, in Patent Document 2, it is necessary to prepare a flexible elastic member having an inclined surface at the tip and having a bag shape. Similarly, in Patent Document 3, it is necessary to prepare a flexible elastic member having a complicated and special shape.

  Thus, in the backflow prevention devices of Patent Documents 2 and 3, since it is necessary to prepare a flexible elastic member having a complicated and special shape as a check valve body, it takes time to prepare the flexible elastic member. There is a problem that it is expensive.

Japanese Patent Laid-Open No. 2006-97779 JP-T-2003-519347 US Pat. No. 5,769,125

  The problem to be solved by the present invention is that there is no restriction on the installation location, and the use of a flexible elastic member having a complicated and special shape as a check valve body prevents back flow in the pipe of an underground structure. An object of the present invention is to provide a backflow prevention device for underground structures that can be used.

According to one aspect of the present invention, a backflow prevention device for the following underground structure is provided.
"A backflow prevention device for underground structures installed in pipelines of underground structures,
A flexible elastic plate having flexibility and elasticity and having a substantially rectangular shape when deployed;
The flexible elastic plate is arranged so that one side on the downstream side in the flow direction of the pipeline is along the inner peripheral surface of the lower side of the pipeline in a state where the flexible elastic plate is mounted in the pipeline. Two sides along the flow direction of the pipe are fixed to the inner peripheral surface of the pipe, and one side on the upstream side in the flow direction of the pipe is fixed to the upper inner peripheral surface of the pipe Backflow prevention device for underground structures. "

  In the following description, “upstream side in the flow direction of the pipeline” and “downstream side in the flow direction of the pipeline” are simply referred to as “upstream side” and “downstream side”.

  In the backflow prevention device of the present invention, the “flexible elastic plate” functions as a check valve body. That is, one side on the downstream side of the flexible elastic plate is arranged along the inner peripheral surface on the lower side of the pipe, and two sides along the flow direction of the pipe are on the inner peripheral surface of the pipe. By fixing one side on the upstream side with respect to the inner peripheral surface on the upper side of the pipe line, the backflow water flowing in the reverse direction in the pipe line is one side on the downstream side of the flexible elastic plate. However, it is blocked by a closed space formed by fixing two sides along the flow direction of the pipeline and one side on the upstream side. Thereby, the backflow in the pipe line of an underground structure can be prevented. On the other hand, the positive flow water flowing in the positive direction flows in from the lower side of the upstream side of the flexible elastic plate, and flows out downstream by pushing up the lower side upward. Thereby, the flow of the positive direction of a pipe line is ensured.

  As described above, the “flexible elastic plate” functions as a check valve body in the backflow prevention device of the present invention. The shape of the “flexible elastic plate” when deployed is substantially rectangular and is simple. That is, according to the present invention, it is possible to prevent the backflow in the pipe of the underground structure without using a flexible elastic member having a complicated and special shape as the check valve body.

Further, in the present invention, the flexible elastic plate can be mounted in the pipe line through an insert inserted and fixed in the pipe line. That is, according to the other viewpoint of this invention, the backflow prevention apparatus for the following underground structures is provided.
"A backflow prevention device for underground structures installed in pipelines of underground structures,
A flexible elastic plate having flexibility and elasticity and having a substantially rectangular shape when deployed;
In the state where the flexible elastic plate is mounted in the pipe via an insert inserted and fixed into the pipe, one side on the downstream side in the flow direction of the pipe is the pipe The two sides along the flow direction of the pipe line are fixed with respect to the inner peripheral surface of the insert body. A backflow prevention device for an underground structure, wherein one side on the upstream side in the flow direction of the pipe is fixed to the inner peripheral surface on the upper side of the insert. "

  When the insert is used in this way, the two sides along the flow direction of the pipe of the flexible elastic plate are fixed with respect to the inner peripheral surface of the insert, and the one side on the upstream side is the inner side of the upper side of the insert. Secure against the circumference. Then, one side on the downstream side is arranged along the lower inner peripheral surface of the pipe line or the lower inner peripheral surface of the insertion body. Thereby, a flexible elastic board fulfill | performs the function as a non-return valve body similarly to the case where an insertion body is not used. That is, two sides along the flow direction of the pipe line are fixed to the inner peripheral surface of the insert body, and one side on the upstream side is fixed to the upper inner peripheral surface of the insert body. Backflow water that flows in the reverse direction tries to flow back over the upper surface of one side on the downstream side of the flexible elastic plate, but the two sides along the flow direction of the pipeline and one side on the upstream side are fixed. It is dammed in a closed space formed by Thereby, the backflow in the pipe line of an underground structure can be prevented. On the other hand, the positive flow water flowing in the positive direction flows in from the lower side of the upstream side of the flexible elastic plate, and flows out downstream by pushing up the lower side upward. Thereby, the flow of the positive direction of a pipe line is ensured.

  When an insert is used in the present invention, the insert may have a shape along the inner peripheral surface above the horizontal plane passing through the center of the conduit. Such a shape of the insert is preferable when applied to a large-diameter pipe. That is, the insert can be reduced in weight and can be easily transported and installed as compared with the case where the insert is shaped along the entire inner peripheral surface of the duct. Note that when the insert is shaped along the inner peripheral surface above the horizontal plane passing through the center of the pipe, the backflow prevention device of the present invention is provided with a pipe in order to securely fix the insert in the pipe. It is preferable to provide a support structure that supports the insert from below in the road.

  In the present invention, it is preferable that the length between two sides along the flow direction of the conduit of the flexible elastic plate is approximately half of the circumferential length of the inner peripheral surface of the conduit. By having such a length relationship, the two sides along the flow direction of the pipe of the flexible elastic plate are respectively the inner peripheral surface of the pipe or the insert at a level near the horizontal plane passing through the center of the pipe. It will be fixed with respect to the inner peripheral surface. Then, the position balance in the pipe line between these two sides, the upstream side and the downstream side becomes good, and the flexible elastic plate stably functions as a check valve body. Can demonstrate.

  Furthermore, the backflow prevention device of the present invention preferably includes a support member that can support the upstream side of the flexible elastic plate from below. As described above, the backflow water is dammed in the closed space formed by fixing the two sides along the flow direction of the pipe line of the flexible elastic plate and the one side on the upstream side during the backflow. Since this closed space is formed on the upper surface side on the upstream side of the flexible elastic plate, the backflow water flows into the upper surface side on the upstream side of the flexible elastic plate. Accordingly, by providing a support member that can support the upstream side of the flexible elastic plate from below, the flexible elastic plate is deformed downward by the water pressure of the reverse flow water, particularly when a large amount of the reverse flow water flows. This can be suppressed. If the flexible elastic plate is excessively deformed by the water pressure due to the backflow water, problems such as water leakage and breakage of the flexible elastic plate may occur. The backflow prevention effect by the elastic plate can be reliably maintained.

  According to the backflow prevention device of the present invention, the “flexible elastic plate having a substantially rectangular shape when unfolded” functions as a check valve body. And the backflow in the pipe line of an underground structure can be prevented, without using the flexible elastic member of a special shape. That is, according to the present invention, it is possible to configure a backflow prevention device for an underground structure with a simple component without causing a problem that it takes time and cost to prepare a flexible elastic member as in the prior art. There is no restriction on the location, and a highly versatile backflow prevention device for underground structures can be provided.

The state which installed the backflow prevention apparatus by 1st Example of this invention in the pipe line is shown, (a) is sectional drawing, (b) is the figure seen from the upstream, (c) is the figure seen from the downstream. is there. It is a figure shown in the state which unfolded the flexible elastic board used for the backflow prevention apparatus of FIG. It is a figure which shows notionally a form when the flexible elastic board in the backflow prevention apparatus of FIG. 1 is seen from the downstream. It is a schematic sectional drawing which shows the installation state of the backflow prevention apparatus by 2nd Example of this invention. It is sectional drawing which shows the backflow prevention apparatus of FIG. 4 independently. The state which installed the backflow prevention apparatus by 3rd Example of this invention in the pipe line of an underground structure is shown, (a) is sectional drawing, (b) is the figure seen from the upstream, (c) is from the downstream. FIG. It is a figure which shows notionally a form when the flexible elastic board in the backflow prevention apparatus of FIG. 6 is seen from the downstream.

  Hereinafter, embodiments of the present invention will be described based on examples shown in the drawings.

(First embodiment)
FIG. 1 shows a state in which a backflow prevention device according to a first embodiment of the present invention is installed in a pipeline, (a) is a sectional view, (b) is a view seen from the upstream side, and (c) is a view from the downstream side. FIG. FIG. 2 is a diagram showing a state in which the flexible elastic plate used in the backflow prevention device is developed, and FIG. 3 is a conceptual view of the flexible elastic plate in the backflow prevention device when viewed from the downstream side. FIG.

  The backflow prevention device of the present invention includes a flexible elastic plate 10 (see FIG. 2) that is flexible and elastic and that is substantially rectangular when deployed, and this is used as a check valve body. In this embodiment, the flexible elastic plate 10 is directly attached and fixed to the pipe line 20 and fixed to the pipe line for the underground structure.

  In this embodiment, the flexible elastic plate 10 is made of a rubber plate having a hardness of about 65, and the unfolded shape is one side 11 on the upstream side and one side 12 on the downstream side as shown by a solid line in FIG. And a rectangular shape (rectangular shape) defined by four sides of two sides 13 and 13 along the flow direction of the pipe. The length of one side 11 on the upstream side and one side 12 on the downstream side, that is, the length between the two sides 13 and 13 along the flow direction of the pipe line is the circumferential length of the inner peripheral surface of the pipe line 20. It is almost half of.

  The two sides 13 and 13 along the flow direction of the duct of the flexible elastic plate 10 are fixed to the inner peripheral surface of the duct 20 along the longitudinal direction (flow direction of the duct). In this embodiment, fixing is performed by bolting using linear presser bars 21 and 21 having substantially the same length as the two sides 13 and 13 along the flow direction of the conduit of the flexible elastic plate 10. . At this time, the length between the two sides 13, 13 along the flow direction of the pipe line is substantially half of the circumferential length of the inner peripheral surface of the pipe line 20 as described above, so it follows the flow direction of the pipe line. The two sides 13 and 13 are fixed to the inner peripheral surface of the pipe line 20 at a level near the horizontal plane passing through the center of the pipe line 20. At this time, one side 12 on the downstream side of the flexible elastic plate 10 is arranged along the inner peripheral surface on the lower side of the pipe line 20. On the other hand, one side 11 on the upstream side of the flexible elastic plate 10 is fixed to the inner peripheral surface on the upper side of the duct 20. In this embodiment, the presser bar 22 having a semicircular arc shape having substantially the same length as the one side 11 on the upstream side is used to fix it by bolt joining.

  The flexible elastic plate 10 can be fixed to the pipe line 20 by the following procedure. First, the flexible elastic plate 10 is inserted into the pipe line 20 so that one side 12 on the downstream side is along the lower inner peripheral surface of the pipe line 20. Thereafter, the two sides 13 and 13 along the flow direction of the pipe line of the flexible elastic plate 10 are fixed to the inner peripheral surface of the pipe line 20 by bolting using linear presser bars 21 and 21. In this state, one side 11 on the upstream side and one side 12 on the downstream side of the flexible elastic plate 10 are both in a state along the inner peripheral surface on the lower side of the pipe line 20. The one side 11 on the side is lifted upward, and the one side 11 on the upstream side is fixed to the inner peripheral surface on the upper side of the pipe line 20 by a bolt connection using a semi-arc-shaped presser bar 22. At this time, the one side 11 on the upstream side of the flexible elastic plate 10 has two sides 13 along the flow direction of the pipe line by the linear presser bars 21 and 21, as shown in FIG. It will be in the state where it turned up in the place which cross | intersects the 13 fixed position.

  If the one side 11 on the upstream side of the flexible elastic plate 10 is folded back as described above and fixed to the inner peripheral surface on the upper side of the conduit 20, both end portions of the one side on the upstream side have a semicircular arc shape. The presser bar 22 protrudes slightly. And the both ends which protruded may be cut off after fixing in order to improve appearance. Then, the shape when the flexible elastic plate 10 is developed becomes a broken line shape with a hatched portion cut out in FIG. 2, and is not exactly a rectangular shape. However, even if a part of the flexible elastic plate 10 is cut out and becomes an exact rectangular shape, the effect of the present invention is not impaired. Therefore, in the present invention, an accurate rectangular shape as shown by a solid line in FIG. 2, a shape close to a rectangular shape in which the hatched portion in FIG. It is defined as “shape”, and it is required that the shape when the flexible elastic plate is developed is substantially rectangular.

  FIG. 3 conceptually shows a form of the flexible elastic plate 10 fixed to the duct 20 as seen from the downstream side. As shown in the figure, one side 12 on the downstream side of the flexible elastic plate 10 is disposed along the inner peripheral surface of the lower side of the pipe line 20, and 2 along the flow direction of the pipe line. The sides 13 and 13 are fixed to the inner peripheral surface of the pipe line 20, and the one side 11 on the upstream side is fixed to the upper inner peripheral surface of the pipe line 20. Thereby, the flexible elastic board 10 exhibits the function as a non-return valve body.

  That is, the backflow water flowing in the reverse direction through the pipe line 20 tries to flow back over the upper surface of the one side 12 on the downstream side of the flexible elastic plate 10 as shown by the broken line arrow in FIG. It is dammed in a closed space formed by fixing the two sides 13, 13 along the flow direction of the pipeline and the one side 11 on the upstream side. Thereby, the backflow in the pipe line 20 can be prevented. The backflow water may flow back (leakage) somewhat from the lower surface of one side 12 on the downstream side of the flexible elastic plate 10 to the upstream side. However, the amount of the water leakage is a problem in the pipes of the underground structure. It is a small amount not to become. Further, when the backflow water is dammed up in the closed space, a downward force acts on the flexible elastic plate 10 due to the water pressure of the backflow water, so that the lower surface of one side 12 on the downstream side of the flexible elastic plate There is no large gap on the side.

  On the other hand, the positive water flowing in the forward direction in the pipe 20 flows from below the one side 11 on the upstream side of the flexible elastic plate 10 as shown by the solid line arrow in FIG. Is pushed upward and flows downstream. Thereby, the flow of the positive direction of the pipe line 20 is ensured.

(Second embodiment)
FIG. 4 is a schematic cross-sectional view showing an installation state of the backflow prevention device according to the second embodiment of the present invention, and FIG. 5 is a cross-sectional view showing the backflow prevention device alone.

  As shown in FIG. 4, the backflow prevention device of the present embodiment is installed in an outflow pipe 41 of a manhole 40 as a conduit for an underground structure, and is particularly suitable for an outflow pipe 41 having a small diameter of about 200 to 300 mm. Installed.

  Similarly to the first embodiment, the backflow prevention device of the present embodiment has flexibility and elasticity as its basic structure, and the flexible elastic plate 10 having a substantially rectangular shape when unfolded is non-returned. In the first embodiment, the flexible elastic plate 10 is directly attached to the conduit, whereas in the present embodiment, the flexible elastic plate 10 is connected to the conduit (outflow pipe 41). It is adapted to be mounted via the insert 30. This is because it is difficult to directly attach the flexible elastic plate 10 to the outflow pipe 41 having a small diameter having an inner diameter of about 200 to 300 mm as in the present embodiment.

  The insertion body 30 has a cylindrical shape so as to follow the shape of the inner peripheral surface of the outflow pipe 41, and at the upstream end thereof, when the backflow prevention device according to this embodiment is installed in the outflow pipe 41 of the manhole 40, A flange 31 for fixing to the inner wall of the manhole 40 is integrally provided.

  As in the first embodiment (see FIG. 2), the flexible elastic plate 10 is unfolded in the form of one side 11 on the upstream side, one side 12 on the downstream side, and the flow direction of the pipeline. The length between the two sides 13 and 13 along the flow direction of the pipe line is the circumferential length of the inner peripheral surface of the insert 30. It is almost half of. Since the inner diameter of the insertion body 30 is substantially equal to the inner diameter of the outflow pipe 41, the length between the two sides 13, 13 along the flow direction of the conduit of the flexible elastic plate 10 is the inner length of the outflow pipe 41. It is also approximately half the circumferential length of the peripheral surface.

  As shown in FIG. 5, in this embodiment, the two sides 13, 13 along the flow direction of the duct of the flexible elastic plate 10 are in the longitudinal direction (the duct of the duct) with respect to the inner peripheral surface of the insert 30. It is fixed along the flow direction. Specifically, as in the first embodiment, linear presser bars 21 and 21 having substantially the same length as the two sides 13 and 13 along the flow direction of the duct of the flexible elastic plate 10 are used. It is fixed by bolting. At this time, since the length between the two sides 13, 13 along the flow direction of the pipe line is substantially half of the circumferential length of the inner peripheral surface of the insert 30 as described above, it follows the flow direction of the pipe line. The two sides 13 and 13 are fixed to the inner peripheral surface of the insert 30 at a level near the horizontal plane passing through the center of the insert 30 (outflow pipe 41). At this time, one side 12 on the downstream side of the flexible elastic plate 10 is arranged along the inner peripheral surface on the lower side of the insert 30. On the other hand, one side 11 on the upstream side of the flexible elastic plate 10 is fixed to the inner peripheral surface on the upper side of the insert 30. Specifically, as in the first embodiment, a semi-arc-shaped presser bar 22 having substantially the same length as the one side 11 on the upstream side is fixed by bolt joining.

  The flexible elastic plate 10 can be fixed to the insert 30 in the same procedure as the fixing to the pipe line 20 described in the first embodiment. However, in this embodiment, since the flexible elastic plate 10 is fixed to the insert 30, the backflow prevention device according to this embodiment is a unit in which the flexible elastic plate 10 is fixed in the insert 30 in advance. Composed. The flexible elastic plate 10 is indirectly fixed to the inner peripheral surface of the outflow pipe 41 by inserting and fixing the insert 30 as the unit into the outflow pipe 41. Similar to the first embodiment, it functions as a check valve body.

(Third embodiment)
6A and 6B show a state in which the backflow prevention device according to the third embodiment of the present invention is installed in the pipe of the underground structure, where FIG. 6A is a cross-sectional view, FIG. 6B is a view seen from the upstream side, and FIG. These are views seen from the downstream side. The backflow prevention device of this embodiment is installed in the outflow pipe 41 of the manhole 40 as in the second embodiment, but the backflow prevention device of this embodiment is suitable for the large diameter outflow pipe 41 having an inner diameter of about 1000 mm. Installed.

  Similarly to the first and second embodiments, the backflow prevention device of the present embodiment has flexibility and elasticity, and reverses the flexible elastic plate 10 that has a substantially rectangular shape when deployed. The flexible elastic plate 10 is provided as a stop valve body, and is attached to the outflow pipe 41 via the insertion body 50.

  In the present embodiment, the insert 50 has a semi-cylindrical shape along the inner peripheral surface above the horizontal plane passing through the center of the outflow pipe 41, but if it is formed as an integral object, it becomes large and is carried into the manhole 40. Since it cannot be performed, it divides | segments into 3 members of the center member 50a and the both end members 50b and 50c along a longitudinal direction (flow direction of a pipe line), and it is made to assemble by field construction. At this time, both ends on the downstream side of the insert 50 are supported from below in the outflow pipe 41 by the support structure 70. In this embodiment, the support structure 70 includes a support substrate 71 formed by bending a plate material disposed along the lower inner peripheral surface of the outflow pipe 41 into a semicircular arc shape, and jack bolts 72 disposed at both ends thereof. The jack bolts 72 at both ends are respectively connected to the downstream end portions of the insert 50, and the jack bolts 72 at both ends support the end portions on the downstream side of the insert 50 from below. To do.

  Further, a flange 60 for fixing the insert 50 to the inner wall of the manhole 40 is connected to the upstream end of the insert 50 in order to fix the insert 50 along the inner peripheral surface of the outflow pipe 41. . The flange 60 is also divided into three members, that is, a central member 60a and both end members 60b and 60c, and is assembled on site.

  As in the first embodiment (see FIG. 2), the flexible elastic plate 10 is unfolded in the form of one side 11 on the upstream side, one side 12 on the downstream side, and the flow direction of the pipeline. The length between the two sides 13 and 13 along the flow direction of the pipe is the circumferential length of the inner peripheral surface of the outflow pipe 41. It is almost half of.

  In the present embodiment, the flexible elastic plate 10 is attached to the outflow pipe 41 via the insertion body 50 by field construction, and functions as a check valve body as in the first embodiment. This on-site construction can be generally performed according to the following procedure.

(1) The central member 50a of the insertion body 50 is inserted into the outflow pipe 41, and positioned using a jack or the like so that the top of the central member 50a matches the top of the inner peripheral surface of the outflow pipe 41.

(2) The central member 60a of the flange 60 is connected to the center member 50a of the inserted insert 50 with bolts and nuts.

(3) The both end members 50b and 50c of the insert 50 are inserted into the outflow pipe 41 and connected to the central member 50a with bolts and nuts, respectively. Subsequently, both end members 60b, 60c of the flange 60 are connected to both end members 50b, 50c of the insert 50 by bolts and nuts, respectively.

(4) After the support structure 70 is disposed at a position corresponding to the downstream end of the insert 50, the jack bolt 72 is connected to both ends of the insert 50 on the downstream side. The jack bolt 72 supports and positions the downstream end portions of the insert 50 so as to push up from below.

(5) The center member 60a and both end members 60b, 60c of the flange 60 are fixed to the inner wall of the manhole 40 with anchor bolts.

(6) The flexible elastic plate 10 is inserted into the outflow pipe 41 such that one side 12 on the downstream side is along the lower inner peripheral surface of the outflow pipe 41.

(7) The two sides 13 and 13 along the flow direction of the conduit of the flexible elastic plate 10 are fixed to the inner peripheral surface of the insertion body 50 by bolting using linear presser bars 51 and 51. . This is the same as in the first embodiment.

(8) In this state, as in the first embodiment, the upstream side 11 and the downstream side 12 of the flexible elastic plate 10 are both on the inner peripheral surface of the lower side of the outflow pipe 41. In this state, one side 11 on the upstream side is lifted upward from this state, and the one side 11 on the upstream side is taken as the inner peripheral surface of the insert 50 (corresponding to the inner peripheral surface on the upper side of the outflow pipe 41) On the other hand, the presser bar 52 having a semicircular arc shape is used to fix it by bolt joining. At this time, one side on the upstream side of the flexible elastic plate 10 is fixed to the fixed positions of the two sides 13 and 13 along the flow direction of the pipe line by the linear presser bars 51 and 51 as in the first embodiment. It will be folded at the intersection.

  By the above field construction, the flexible elastic plate 10 has a form as shown in FIG. 7 as in the first embodiment. That is, one side 12 on the downstream side of the flexible elastic plate 10 is arranged along the inner peripheral surface on the lower side of the outflow pipe 41, and two sides 13 and 13 along the flow direction of the pipe line are inserted bodies. The first side 11 on the upstream side is fixed to the inner peripheral surface of the insertion body 50. Thereby, the flexible elastic board 10 exhibits the function as a non-return valve body similarly to 1st Example.

  However, in the case of the present embodiment, since the outflow pipe 41 has a large diameter, a large amount of backflow water is blocked in the closed space, and the flexible elastic plate 10 may be greatly deformed downward due to water pressure by the backflow water. is there. In order to cope with this, in this embodiment, as shown by a one-dot chain line in FIG. 6A, a support member 80 capable of supporting the upstream side of the flexible elastic plate 10 from below can be installed as an option.

  In the present embodiment, the support member 80 is a rod-shaped member, and one end of the support member 80 can be pivoted by being pivotally supported by the central member 50a of the insertion body 50. In the installed state, the other end is below the outflow pipe 41. It is positioned by abutting against the inner peripheral surface of the side. By installing the support member 80 in this way, even if a large amount of backflow water flows in, it is possible to suppress the flexible elastic plate from being deformed downward by water pressure due to the backflow water. Further, since the support member 80 is rotatable about one end thereof, the normal flow water flowing in the forward direction through the outflow pipe 41 can be rotated upward in accordance with the flow, so the normal flow water is There is no hindrance to the flow.

  In this embodiment, the support member 80 is a rod-shaped member, but the shape is not limited to a rod-shape. In short, any material that can support the upstream side of the flexible elastic plate 10 from below may be used, and for example, it may be formed of a planar member. Further, the site construction procedure is not limited to the above-described procedure, and the center member 60a of the flange 60 and both end members 60b, 60c are fixed to the inner wall of the manhole 40 with anchor bolts, and then the center of the insert 50 is fixed. You may change suitably, such as inserting the member 50a in the outflow pipe 41. FIG.

  Further, in the present embodiment, the insert 50 and the flange 60 are each divided into three members, ie, a central member and both end members, in the vertical direction, but the number of divisions and the division direction are arbitrary, and may be divided in the radial direction, for example. Is possible.

  Further, in the above embodiment, the one side 12 on the downstream side of the flexible elastic plate 10 is arranged so as to be in close contact with the inner peripheral surface on the lower side of the pipe (insert), In order to secure the flow path in advance, the lower end portion of one side 12 on the downstream side of the flexible elastic plate 10 is slightly lifted upward along the inner peripheral surface of the lower side of the pipe line (insert). It can also arrange | position and can provide a clearance gap as a flow path of positive flow water. That is, in the present invention, such a gap is also included in the concept of “arranging along the lower inner peripheral surface of the pipe (insert)”. Even if such a gap is provided in this way, the amount of water leakage to the upstream side of the backflow water does not cause a problem in the pipe line of the underground structure. In addition, when the backflow water flows into the above-mentioned closed space, a downward force acts on the flexible elastic plate due to the water pressure of the backflow water, so that the gap does not expand during backflow. However, since it is in the direction of shrinking, the backflow prevention effect is sufficiently exhibited.

  In the first embodiment, the backflow prevention device is installed in the middle of the pipe, and in the second and third embodiments, the backflow prevention device is installed in the outflow pipe of the manhole. However, the present invention is not limited to this. However, it may be installed at the manhole inflow pipe or at the end of the pipe.

DESCRIPTION OF SYMBOLS 10 Flexible elastic board 11 One side of upstream side 12 One side of downstream side 13 Two sides along the flow direction of a pipe line 20 Pipe line 21 Linear presser bar 22 Semi-circular presser bar 30 Insert 31 Flange 40 Manhole (underground structure)
41 Outflow pipe (pipe)
DESCRIPTION OF SYMBOLS 50 Insert 50a Center member 50b, 50c Both-ends member 51 Linear presser bar 52 Semi-circular presser bar 60 Flange 60a Central member 60b, 60c Both-ends member 70 Support structure 71 Support substrate 72 Jack bolt 80 Support member

Claims (5)

A backflow prevention device for an underground structure installed in a pipeline of the underground structure,
A flexible elastic plate having flexibility and elasticity and having a substantially rectangular shape when deployed;
The flexible elastic plate is arranged so that one side on the downstream side in the flow direction of the pipeline is along the inner peripheral surface of the lower side of the pipeline in a state where the flexible elastic plate is mounted in the pipeline. Two sides along the flow direction of the pipe are fixed to the inner peripheral surface of the pipe, and one side on the upstream side in the flow direction of the pipe is fixed to the upper inner peripheral surface of the pipe Backflow prevention device for underground structures. A backflow prevention device for an underground structure installed in a pipeline of the underground structure,
A flexible elastic plate having flexibility and elasticity and having a substantially rectangular shape when deployed;
In the state where the flexible elastic plate is mounted in the pipe via an insert inserted and fixed into the pipe, one side on the downstream side in the flow direction of the pipe is the pipe The two sides along the flow direction of the pipe line are fixed with respect to the inner peripheral surface of the insert body. A backflow prevention device for an underground structure, wherein one side on the upstream side in the flow direction of the pipe is fixed to the inner peripheral surface on the upper side of the insert.   The said insertion body has a shape which follows the inner peripheral surface above the horizontal surface which passes along the center of the said pipe line, and is further provided with the support structure which supports this insert body from the downward direction in the said pipe line. The backflow prevention device for underground structures as described in 1.   The length between two sides along the flow direction of the said pipe line of the said flexible elastic board is a substantially half of the circumferential direction length of the internal peripheral surface of the said pipe line. Backflow prevention device for underground structures.   The backflow prevention device for an underground structure according to any one of claims 1 to 4, further comprising a support member capable of supporting the upstream side of the flexible elastic plate from below.

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