Drain pipe ventilation facility

Abstract

To provide a drain pipe ventilation facility which can stably open a pressure and suck air according to a change in pressure generated in a drain pipe.SOLUTION: An upper opening lid 3 for closing an upper opening 11 of a drain frame body 2 includes: a pressure opening 16 for communicating an inner void part 13 of the drain frame body 2 with outside; and a pressure opening lid 17 for converting the pressure opening 16 into a closed state and an open state. A pipe pressure opening lid 22 for closing a drain port part 102 communicating with a drain pipe includes: a pipe pressure opening port part 21 for communicating the drain pipe with the inner void part 13; and a pipe pressure opening lid 22 for converting the pipe pressure opening port part 21 into a close state and an open state. When the inner pressure of the drain pipe increases, in the configuration, the pipe pressure opening port part 21 and the pressure opening 16 are sequentially opened, and the inner pressure of the drain pipe can be opened.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a drainage pipe ventilation system that is installed in an opening such as a manhole or inspection hatch to close the opening. [Background technology]

[0002] A known configuration is one in which a drainage pipe such as a sewer is connected to the interior space of a protective frame buried underground and opens to the surface through an upper opening of the protective frame. For example, Patent Document 1 proposes a configuration including an outer lid that closes the upper opening and an inner lid that closes a drain outlet that opens into the interior space of the protective frame and is connected to the drainage pipe.

[0003] In such drainage pipes, when a large amount of water flows during heavy rain and the pressure increases, it is necessary to prevent the drainage pipe from being damaged by this pressure. For example, Patent Document 2 proposes a configuration in which an outer cover that closes the opening that opens to the ground surface is provided with a pressure release cover that opens as the pressure in the drainage pipe increases.

[0004] On the other hand, for example, Patent Document 3 proposes a configuration in which an outer cover that closes an opening on the ground that is connected to a drain pipe is provided with an intake valve that opens in response to negative pressure generated in the drain pipe. This intake valve opens when negative pressure occurs in the drain pipe, and this opening operation allows air to be sucked in from the outside to eliminate the negative pressure. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-275926 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-172322 [Patent Document 3] Japanese Patent Application Laid-Open No. 2001-140313 Summary of the Invention [Problem to be solved by the invention]

[0006] In a conventional configuration in which a drain pipe is connected to the inner space of a protective frame, as in Patent Document 1, the inner space of the protective frame is closed by an outer lid, so pressure changes occurring in the drain pipe are transmitted to the outer lid via the inner space. However, in this conventional configuration, the drain outlet opening into the inner space is closed by the inner lid, so pressure changes occurring in the drain pipe are not transmitted to the inner space. Therefore, even if the outer lid of this conventional configuration is equipped with a pressure release lid as in Patent Document 2 or an intake valve as in Patent Document 3, these cannot be activated by pressure changes in the drain pipe, and there is a problem in that pressure changes in the drain pipe cannot be resolved.

[0007] The present invention proposes a drain pipe ventilation system that can appropriately release pressure and suction air in response to pressure changes occurring in the drain pipe. [Means for solving the problem]

[0008] The first aspect of the present invention is a drainage frame having an upper opening that opens upward and an internal space that communicates with the inside of a drain pipe via a drain outlet provided below the upper opening, the drainage frame having an opening lid device that is disposed at the upper opening and covers the upper opening, and a drainage lid device that is disposed at the drain outlet and covers the drain outlet, the opening lid device having a pressure release lid that is provided so as to be convertible between a closed state that closes the internal space of the drainage frame and an open state that is raised from the closed state to open the internal space, and the opening lid device has a pressure release lid that is provided so as to be convertible between a closed state that closes the internal space of the drainage frame and an open state that is raised from the closed state to open the internal space, and the pressure in the drainage frame is reduced to a predetermined value. This drain pipe ventilation equipment is characterized in that it is equipped with a first pressure release means that, when the internal pressure of the drain frame exceeds a predetermined pressure, causes the pressure release lid to be converted from the closed state to the open state, and the drain lid device is equipped with a pipe pressure release lid that can be converted between a closed state that closes the drain pipe and an open state that is raised from the closed state to open the drain pipe, and is equipped with a second pressure release means that, when the internal pressure of the drain pipe exceeds a predetermined pressure, causes the pipe pressure release lid to be converted from the closed state to the open state, by the internal pressure of the drain pipe.

[0009] With this configuration, an increase in pressure (internal pressure) generated inside the drain pipe causes the pipe pressure release cover to switch to an open state, and an increase in the internal pressure of the drain frame due to the opening of the drain pipe causes the pressure release cover to switch to an open state. As a result, the drain pipe is connected to the outside through the internal space of the drain frame, and the pressure inside the drain pipe can be released. In this way, an increase in pressure in the drain pipe can stably switch the pipe pressure release cover and pressure release cover to their open states, thereby preventing an increase in pressure in the drain pipe and suppressing damage to the drain pipe due to this pressure increase.

[0010] In the configuration of the present invention, the predetermined pressure for converting the pressure release lid to the open state and the predetermined pressure for converting the pipe pressure release lid to the open state can be set as appropriate and may be different or the same. Preferably, the predetermined pressure for converting the pipe pressure release lid to the open state is higher than the predetermined pressure for converting the pressure release lid to the open state. With this configuration, when the pipe pressure release lid is converted to the open state, the pressure transmitted from the drain pipe to the inner space of the drain frame can convert the pressure release lid to the open state, so the pipe pressure release lid and the pressure release lid can be converted to the open state sequentially. This allows the pressure in the drain pipe to be released smoothly.

[0011] In the drain pipe ventilation system of the first invention described above, a configuration is proposed in which the weight of the pipe pressure release cover is heavy compared to the weight of the pressure release cover. Here, the first pressure release means keeps the pressure release lid in a closed state by its own weight, and the predetermined pressure for converting the pressure release lid to an open state is the pressure required to lift the pressure release lid. Similarly, the second pressure release means keeps the tube pressure release lid in a closed state by its own weight, and the predetermined pressure for converting the tube pressure release lid to an open state is the pressure required to lift the tube pressure release lid.

[0012] In this configuration, the internal pressure of the drainage frame required to open the pressure release lid is lower than the internal pressure of the drain pipe required to open the pipe pressure release lid, so when the pipe pressure release lid is opened by the internal pressure of the drainage pipe, the internal pressure of the drainage frame increased by the pressure transmitted from the drain pipe also opens the pressure release lid. In this way, with this configuration, the pipe pressure release lid and the pressure release lid can be opened sequentially by increasing the internal pressure of the drain pipe, and the pressure built up in the drain pipe can be smoothly released to the outside.

[0013] In the drain pipe ventilation equipment of the first invention described above, the drain lid device comprises a drain lid that closes the drain outlet portion, and a pipe pressure release opening portion that is formed on the drain lid so as to connect the inside of the drain pipe with the inner space of the drain frame, and to which a pipe pressure release lid is attached so as to be able to move up and down, and when the pipe pressure release lid is closed, the pipe pressure release opening portion is closed, and when the pipe pressure release lid is open, the pipe pressure release opening portion is opened, and a configuration is proposed in which the weight of the pipe pressure release lid is lighter than the weight of the drain lid and heavier than the weight of the pressure release lid of the opening lid device. Here, the drain cover closes the drain outlet by its own weight, and the second pressure release means closes the pipe pressure release port by its own weight. The predetermined pressure that opens the pipe pressure release port (in other words, the predetermined pressure that changes the pipe pressure release cover to an open state) is the pressure required to lift the pipe pressure release cover. The first pressure release means keeps the pressure release cover in a closed state by its own weight, and the predetermined pressure that changes the pressure release cover to an open state is the pressure required to lift the pressure release cover.

[0014] In this configuration, the internal pressure of the drainage frame required to open the pressure release lid is lower than the internal pressure of the drain pipe required to open the pipe pressure release lid. Therefore, when the pipe pressure release port is opened by the internal pressure of the drainage pipe, the internal pressure of the drainage frame, increased by the pressure transmitted from the drain pipe, opens the pressure release lid. Here, since a pressure greater than that required to open the pipe pressure release port is required to open the drainage lid, if the internal pressure of the drain pipe increases, the pipe pressure release lid can be raised while keeping the drainage lid closed, allowing the pipe pressure release port to be opened stably. Thus, even with this configuration, the pipe pressure release lid and the pressure release lid can be sequentially opened as the internal pressure of the drain pipe increases, allowing the pressure built up in the drain pipe to be smoothly released to the outside.

[0015] The second aspect of the present invention is a drainage frame having an upper opening that opens upward and an internal space that communicates with the inside of a drain pipe via a drain outlet provided below the upper opening, and an opening lid device that is arranged on the upper opening and covers the upper opening, wherein the opening lid device is provided with an air vent closing lid that can be converted between a closed state that closes the internal space of the drainage frame and an open state that is raised or lowered from the closed state to open the internal space, and is provided with an air vent opening means that converts the air vent closing lid from the closed state to the open state due to pressure acting on the air vent closing lid, and further comprises a pressure transmission means that is arranged in the internal space of the drainage frame and, at least when the air vent closing lid is in the closed state, prevents water from entering the drain pipe and applies pressure generated inside the drain pipe to the air vent closing lid, and the pressure acting on the air vent closing lid via the pressure transmission means converts the air vent closing lid to the open state.

[0016] With this configuration, pressure changes occurring inside the drain pipe can be directly applied to the vent closing cover by the pressure transmission means, so that the vent closing cover can be stably switched to an open state in response to pressure changes inside the drain pipe. Switching the vent closing cover to an open state also connects the inside of the drain pipe to the outside, eliminating pressure changes occurring inside the drain pipe. Therefore, with this configuration, it is possible to prevent problems caused by pressure changes inside the drain pipe.

[0017] Furthermore, in the conventional configuration described above, in which a drainage outlet is provided in the inner cavity of the protective frame, rainwater can enter the inner cavity during rainfall through gaps in the outer lid that closes the upper opening. If rainwater that has entered the inner cavity accumulates, water pressure acts on the inner lid that closes the drainage outlet, making it difficult to open. Furthermore, in a conventional configuration with a protective frame, in which the inner lid is not provided and the drainage outlet is always open, rainwater that has entered the inner cavity of the protective frame flows into the drainage pipe, increasing the flow rate of the drainage pipe and increasing the burden on the drainage treatment. In contrast, the second configuration of the present invention solves the problems of the conventional configuration described above by using a water-impermeable pressure transmission means to prevent rainwater from entering directly above the drainage outlet.

[0018] In the drain pipe ventilation equipment of the second invention described above, the vent opening means of the opening cover device raises the vent closing cover and converts it to an open state when a pressure of a predetermined pressure or more acts on the vent closing cover from below, and the pressure transmission means comprises a non-permeable pressure transmission cylinder whose lower end is connected to the inside of the drain pipe and whose upper end is in close contact with the vent closing cover when the vent closing cover is closed, but which is separated from the vent closing cover when the vent closing cover is open, and a configuration is proposed in which when the vent closing cover is closed, the internal pressure of the drain pipe acts on the vent closing cover through the pressure transmission cylinder, converting the vent closing cover to an open state.

[0019] In this configuration, when the vent cover is closed, the pressure transmission cylinder can directly apply the internal pressure of the drain pipe to the vent cover, so that an increase in pressure generated in the drain pipe can stably switch the vent cover to an open state. Furthermore, when the vent cover is open, the upper end of the pressure transmission cylinder is separated from the vent cover, so the inside of the drain pipe is opened through the pressure transmission cylinder, and the increase in pressure generated inside the drain pipe can be resolved. Therefore, this configuration can prevent damage to the drain pipe caused by an increase in internal pressure.

[0020] Furthermore, the specified pressure that converts the vent closing cover to an open state is the pressure required to lift the vent closing cover, and if, for example, the vent closing cover is configured to be kept closed by its own weight, it is a pressure that can lift the weight of the vent closing cover.

[0021] Furthermore, in the drain pipe ventilation equipment according to the second invention described above, the pressure transmission cylinder is formed from an elastic material and expands and contracts by elastic deformation in the vertical direction, and when the vent closing cover is in the closed state, it is elastically contracted by the weight acting from the vent closing cover, so that the upper end is tightly pressed against the vent closing cover.

[0022] In this configuration, the upper end of the pressure transmission cylinder is stably and tightly attached to the vent closure cover when the vent closure cover is closed, so that the internal pressure of the drain pipe can be reliably applied to the vent closure cover via the pressure transmission cylinder. As a result, the internal pressure of the drain pipe increases, and the vent closure cover can be more stably converted to the open state.

[0023] Furthermore, a configuration is proposed in which the drain pipe ventilation equipment of the second invention described above is equipped with a drain lid device that is arranged at the drain outlet and covers the drain outlet, and the drain lid device is equipped with a pipe pressure release lid that is capable of being converted between a closed state that closes the drain outlet and an open state that is raised from the closed state to open the drain outlet, and is equipped with pipe pressure release means that, when the internal pressure of the drain pipe reaches a predetermined pressure or higher, causes the pipe pressure release lid to be converted from the closed state to the open state by the internal pressure of the drain pipe.

[0024] In this configuration, when the pipe pressure release cover is opened due to an increase in the internal pressure of the drain pipe, this internal pressure can be applied directly to the vent closing cover via the pressure transmission cylinder. This allows the operation from opening the pipe pressure release cover to opening the vent closing cover to be performed quickly, allowing the internal pressure of the drain pipe to be released smoothly.

[0025] In this configuration, the air space directly above the pipe pressure release cover is surrounded by the pressure transmission cylinder, preventing rainwater and other contaminants from entering the air space directly above. As mentioned above, during rainfall, rainwater can enter the internal space of the drainage frame through gaps in the outer cover that closes the upper opening and accumulate there. However, in this configuration, the water pressure of the accumulated rainwater does not act on the pipe pressure release cover. Therefore, regardless of whether rainwater accumulates in the internal space of the drainage frame, the pipe pressure release cover can be stably switched to an open state by increasing the internal pressure of the drain pipe, thereby relieving the internal pressure, thereby stably achieving the aforementioned advantageous effect of the present invention.

[0026] In the drain pipe ventilation equipment of the second invention described above, the opening cover device comprises an upper opening cover that closes the upper opening, and an air vent section formed on the upper opening cover so as to connect the internal space of the drain frame with the outside, and in which the air vent closing cover is arranged so as to be able to move up and down, and when the air vent closing cover is in a closed state, it closes the air vent section, and when the air vent closing cover is in an open state after being lowered from the closed state, it opens the air vent section, and the pressure transmission means comprises a water-impermeable pressure transmission cylinder that connects the drain outlet section and the air vent section, and a configuration is proposed in which negative pressure generated inside the drain pipe acts on the air vent closing cover through the pressure transmission cylinder, converting the air vent closing cover to an open state.

[0027] In this configuration, the pressure inside the drain pipe can be directly applied to the vent cover by the pressure transmission cylinder, so the negative pressure generated inside the drain pipe can stably switch the vent cover to an open state. This allows the negative pressure in the drain pipe to be properly released. Furthermore, this configuration can prevent rainwater that has entered through gaps in the outer cover during rainfall from entering the drain outlet, preventing a large amount of water from flowing into the drain pipe due to the negative pressure generated in the drain pipe, and also ensures the aforementioned negative pressure is released reliably and stably. [Effects of the Invention]

[0028] According to the drain pipe ventilation equipment of the first invention described above, the pipe pressure release cover and the pressure release cover can each be stably converted to an open state as the internal pressure of the drain pipe increases, and the inside of the drain pipe can be connected to the outside, thereby eliminating the increase in internal pressure of the drain pipe and preventing the drain pipe from being damaged by the increase in internal pressure.

[0029] Furthermore, according to the drain pipe ventilation equipment of the second invention described above, the vent closing cover can be stably converted to an open state due to pressure changes occurring inside the drain pipe, and the inside of the drain pipe can be connected to the outside, thereby eliminating pressure changes inside the drain pipe and suppressing the occurrence of malfunctions caused by such pressure changes. [Brief explanation of the drawings]

[0030] [Figure 1] 1 is a cross-sectional view showing the installation state of a drainage pipe ventilation system 1 according to first and second embodiments of the present invention. [Figure 2] 1 is a perspective view showing a drainage frame 2 and an upper opening cover 3 that constitute the drainage pipe ventilation equipment 1. FIG. [Figure 3] 2 is a cross-sectional view showing the upper opening cover 3, the drainage frame 2, and the drainage cover 5 separated from each other. [Figure 4] 1 is an explanatory diagram showing a pressure release mode in the drain pipe ventilation equipment 1. FIG. [Figure 5] FIG. 10 is a cross-sectional view showing the installation state of the drainage pipe ventilation equipment 31 of the third embodiment. [Figure 6] 10 is an explanatory diagram showing a negative pressure release mode in the drain pipe ventilation equipment 31. FIG. [Figure 7] 10 is an explanatory diagram showing the internal pressure release mode in the drain pipe ventilation equipment 31. FIG. [Figure 8] FIG. 10 is a cross-sectional view showing the installation state of the drainage pipe ventilation system 51 of the fourth embodiment. [Figure 9] 10 is an explanatory diagram showing a negative pressure release mode in the drain pipe ventilation equipment 51. FIG. [Figure 10] FIG. 10 is a cross-sectional view showing the installation state of the drainage pipe ventilation equipment 71 of the fifth embodiment. [Figure 11] 10 is an explanatory diagram showing a pressure release mode in the drain pipe ventilation equipment 71. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0031] Examples 1 to 5 embodying the drain pipe ventilation system according to the present invention will be described in detail below. [Example]

[0032] The drain pipe ventilation equipment 1 of Example 1 is for releasing the internal pressure that has increased in a drain pipe buried underground to the outside (atmosphere) through a vertical pipe 101 that is connected to the drain pipe, and is arranged so as to cover the upper end (drain outlet 102) of the vertical pipe 101, as shown in Figure 1. The drain pipe (not shown) and the vertical pipe 101 are buried underground, and a paved area S is constructed around the drain pipe ventilation equipment 1 using asphalt, concrete, or the like that is paved on the ground G. Here, the drain outlet 102 that opens at the upper end of the vertical pipe 101 is exposed to the ground G through an opening (not shown) in a base M that is provided on the ground G.

[0033] The drain pipe ventilation equipment 1 comprises an approximately cylindrical drain frame body 2 installed on the base M, an upper opening lid 3 that closes the upper opening 11 of the drain frame body 2, a lid receiving frame 4 attached to the drain outlet portion 102 of the vertical pipe 101, and a drain lid 5 that is attached to the lid receiving frame 4 and closes the drain outlet portion 102.

[0034] As shown in Figures 1 to 3, the drainage frame 2 has a generally cylindrical shape that is open in the vertical direction, and includes at its upper part the upper opening 11 that is closed by the upper opening lid 3, and at its lower part a circular mounting portion 12 that is mounted on the base M. The drainage frame 2 includes an inner space 13 that communicates with the drain outlet 102 of the vertical pipe 101, and the inner space 13 is opened upward by the upper opening 11. That is, when the drainage lid 5 and the upper opening lid 3 are not attached, the drain outlet 102 of the vertical pipe 101 opens upward through the inner space 13 and the upper opening 11 of the drainage frame 2. On the other hand, when the upper opening 11 and the drain outlet 102 are closed, the inner space 13 of the drainage frame 2 is closed from the inside of the vertical pipe 101 (the inside of the drainage pipe) and the outside.

[0035] The upper opening lid 3 has a pressure opening 16 that penetrates in the vertical direction, and a pressure release lid 17 that closes the pressure opening 16, and the pressure release lid 17 is provided so as to be movable up and down relative to the pressure opening 16. The pressure release lid 17 has a main lid portion 17a and a pressure-receiving shaft portion 17b that protrudes downward from the main lid portion 17a, and the pressure-receiving shaft portion 17b is formed with a diameter smaller than the pressure opening 16 and is inserted through the pressure opening 16 to protrude downward. A lid receiving portion 18 to which the main lid portion 17a of the pressure release lid 17 is attached is provided on the upper surface of the upper opening lid 3, and when the main lid portion 17a of the pressure release lid 17 is attached to the lid receiving portion 18 (hereinafter referred to as the closed state), the pressure opening 16 is closed by the pressure release lid 17. Furthermore, when the pressure release lid 17 is raised upward from the closed state in which it is attached to the lid receiving portion 18, the pressure opening portion 16 is opened (see FIG. 4(B)). When the pressure release lid 17 is raised and opens the pressure opening portion 16 (hereinafter referred to as the open state), the inner space 13 of the drainage frame 2 is connected to the outside. The pressure release lid 17 is maintained in the closed state in which it is attached to the lid receiving portion 18 of the upper opening lid 3 by its own weight, and is raised from the closed state to the open state when it is lifted upward. Then, when this lifting force is released, it moves down from the open state to the closed state.

[0036] Furthermore, a peripheral wall 19 is provided on the back surface of the upper opening lid 3 so as to surround the pressure-receiving shaft 17b of the pressure release lid 17 protruding from the pressure opening 16. This peripheral wall 19 can protect the pressure-receiving shaft 17b of the pressure release lid 17 from external impacts and can efficiently transmit pressure transmitted from the vertical pipe 101 to the pressure-receiving shaft 17b, as will be described later.

[0037] In this embodiment, the pressure opening 16 (pressure opening lid 16) is provided at a position offset (horizontally displaced) from the center of the upper opening lid 3. This is to prevent interference with a locking member (not shown) provided on the upper opening lid 3. This locking member is used to lock the upper opening lid 3 to the upper opening 11 of the drainage frame 2. If the shape of the locking member and the size of the upper opening lid do not cause interference with the locking member, it is preferable to provide the pressure opening (pressure opening lid) at the center of the upper opening lid (directly above the pipe pressure opening 21). This is because the pressure of the drainage pipe released through the pipe pressure opening 21 can be efficiently transmitted to the pressure opening lid.

[0038] The lid receiving frame 4 has a substantially circular ring shape and is fitted into the drain outlet portion 102 of the vertical pipe 101. When the lid receiving frame 4 is fitted into the drain outlet portion 102, the drain outlet portion 102 is open upward, and when the drain lid 5 is attached to the lid receiving frame 4, the drain outlet portion 102 is closed.

[0039] The drainage lid 5 includes a pipe pressure release port 21 that penetrates in the vertical direction, and a pipe pressure release lid 22 that closes the pipe pressure release port 21, and the pipe pressure release lid 22 is provided so as to be movable up and down relative to the pipe pressure release port 21. A lid receiving portion 23 to which the pipe pressure release lid 22 is attached is provided on the upper surface of the drainage lid 5, and when the pipe pressure release lid 22 is attached to the lid receiving portion 23 (hereinafter referred to as the closed state), the pipe pressure release port 21 is closed by the pipe pressure release lid 22. When the pipe pressure release lid 22 is raised from the closed state in which it is attached to the lid receiving portion 23, the pipe pressure release port 21 is opened (see FIG. 4 ). When the pipe pressure release lid 22 is raised and the pipe pressure release port 21 is open (hereinafter referred to as the open state), the interior of the vertical pipe 101 and the inner space 13 of the drainage frame 2 are in communication. The pipe pressure release lid 22 is maintained in a closed state attached to the lid receiving portion 23 of the drainage lid 5 by its own weight, and is raised from the closed state to an open state when lifted upward. When this lifting force is released, the lid 22 moves down from the open state to the closed state. The pipe pressure release lid 22 of this Example 1 is configured to include a main lid portion (not shown) attached to the lid receiving portion 23 of the drainage lid 5, and a pressure receiving shaft portion (not shown) inserted into the pipe pressure release opening portion 21 and protruding downward.

[0040] The drain cover 5 may also be provided with a locking member to prevent it from coming off the cover receiving frame 4. This locking member may be, for example, a locking member that is rotatably mounted on the drain cover 5 and that, when rotated, switches between a locked state in which it engages with the inner wall of the cover receiving frame 4 and an unlocked state in which it is released from the engagement. A locking member of this configuration has a rotating operating part on the top surface of the drain cover 5, and can be switched between the locked state and the unlocked state by manually operating the operating part. The operating part may be configured to be operable with a predetermined jig or may be configured to be directly operated by an operator. The latter configuration, in particular, does not require a jig, making it easy to attach and detach the drain cover.

[0041] In the configuration of the first embodiment, the drainage frame 2, the upper opening lid 3, the lid receiving frame 4, and the drainage lid 5 are made of metal. From the viewpoint of machining, metals used for cast products are preferred, and more specifically, cast iron is preferably used. The pressure release lid 17 and the pipe pressure release lid 22 are formed of a material other than resin (e.g., metal). The pressure release lid 17 is attached to the upper opening lid 3 and is smaller and lighter than the upper opening lid 3. Similarly, the pipe pressure release lid 22 is attached to the drainage lid 5 and is smaller and lighter than the drainage lid 5. Furthermore, in the first embodiment, the pipe pressure release lid 22 is heavier than the pressure release lid 17. Therefore, a greater force is required to switch the pipe pressure release lid 22 from a closed state to an open state than the force required to switch the pressure release lid 17 from a closed state to an open state.

[0042] That is, in the first embodiment, as will be described later, the pipe pressure release cover 22 is changed from a closed state to an open state due to the increased internal pressure in the drain pipe. Then, the internal pressure of the internal space 13 increases due to the pressure released from the inside of the vertical pipe 101 to the internal space 13 of the drain frame 2 through the pipe pressure release port 21, and the pressure release cover 17 is changed from a closed state to an open state. Here, in order to change the pipe pressure release cover 22 from a closed state to an open state, pressure is required to lift the weight of the pipe pressure release cover 22, so the internal pressure of the drain pipe that changes the pipe pressure release cover 22 to an open state is determined according to the weight of the pipe pressure release cover 22. In other words, the weight of the pipe pressure release cover 22 can be set based on the upper limit (threshold) of the internal pressure increase in the drain pipe. Similarly, the internal pressure of the inner space 13 of the drainage frame 2 that converts the pressure release lid 17 into the open state is determined according to the weight of the pressure release lid 17, and the weight of the pressure release lid 17 can be set based on the upper limit (threshold) of the internal pressure increasing in the inner space 13.

[0043] Next, the operation of the drain pipe ventilation system 1 of the first embodiment will be described. Under normal conditions, a sufficient amount of water flows through the drain pipe, and the internal pressure does not increase to the level required to lift the pipe pressure release lid 22 of the drain pipe ventilation equipment 1, so as shown in Figure 1, the pipe pressure release lid 22 and the pressure release lid 17 are each held in a closed position by their own weight.

[0044] When the amount of water flowing through the drain pipe increases due to heavy rain or the like and the internal pressure of the drain pipe exceeds the pressure required to lift the pipe pressure release cover 22 of the drain cover 5, the pressure acting on the pipe pressure release cover 22 from the vertical pipe 101 causes the pipe pressure release cover 22 to rise from the closed state and change to the open state, as shown in Figure 4(A). As a result, the internal pressure of the drain pipe is released to the inner space 13 of the drain frame 2 through the vertical pipe 101 and the pipe pressure release port 21.

[0045] When the pipe pressure release port 21 of the drain cover 5 is opened, the internal pressure of the drain pipe is transmitted to the internal space 13 of the drain frame 2, increasing the internal pressure of the internal space 13. When the internal pressure of the internal space 13 exceeds the pressure required to lift the pressure release cover 17 of the upper opening cover 3, the pressure acting on the pressure release cover 17 causes the pressure release cover 17 to rise from the closed state to the open state, as shown in Figure 4(B). As a result, the internal pressure of the internal space 13 of the drain frame 2 is released, and the internal pressure of the drain pipe is released to the outside via the vertical pipe 101 and the internal space 13 of the drain frame 2, thereby suppressing an increase in the internal pressure of the drain pipe.

[0046] With both the pipe pressure release port 21 and the pressure opening 16 open, when the internal pressure of the drain pipe decreases and becomes lower than the pressure that lifts the pipe pressure release lid 22, the pipe pressure release lid 22 changes from the open state to the closed state. As a result, the internal pressure of the inner space 13 of the drain frame 2 also decreases, and the pressure release lid 17 changes from the open state to the closed state. In this way, the normal state is restored.

[0047] In the drain pipe ventilation equipment 1 of the first embodiment, the drain cover 5 that closes the drain outlet 102 of the vertical pipe 101 is provided with a pipe pressure release cover 22 that opens when the internal pressure of the drain pipe increases, and the upper opening cover 3 that closes the upper opening 11 of the drain frame 2 is provided with a pressure release cover 17 that opens when the internal pressure of the inner space 13 of the drain frame 2 increases. With this configuration, when the internal pressure of the drain pipe increases, the pipe pressure release port 21 opens, and when the internal pressure of the inner space 13 of the drain frame 2 increases due to pressure transmitted from the drain pipe, the pressure opening 16 opens. Here, since the pipe pressure release cover 22 is heavier than the pressure release cover 17, the pressure transmitted from the drain pipe to the inner space 13 of the drain frame 2 when the pipe pressure release cover 22 is raised (the pipe pressure release port 21 is opened) can raise the pressure release cover 17. As described above, according to the configuration of the first embodiment, the pipe pressure release lid 22 can be raised (opening the pipe pressure release port 21) and the pressure release lid 17 can be raised (opening the pressure opening 16) in a stable sequence as the internal pressure of the drain pipe increases. Therefore, the pressure in the drain pipe that increases during heavy rain or the like can be smoothly released to the outside, and damage to the drain pipe due to the increase in pressure can be prevented.

[0048] In the configuration of Example 1, the upper opening lid 3 (and pressure opening 16) and pressure release lid 17 correspond to the opening lid device of the present invention. The pressure opening 16 and pressure release lid 17 correspond to the first pressure release means of the present invention. The drainage lid 5 (and pipe pressure release port 21), lid receiving frame 4, and pipe pressure release lid 22 correspond to the drainage lid device of the present invention. The pipe pressure release port 21 and pipe pressure release lid 22 correspond to the second pressure release means of the present invention. The internal pressure of the inner space 13 of the drainage frame 2, which raises the pressure release lid 17 attached to the upper opening 11 by its own weight, corresponds to the predetermined pressure that converts the pressure release lid of the present invention from a closed state to an open state. The internal pressure of the drainage pipe (vertical pipe 101), which raises the pipe pressure release lid 22 attached to the lid receiving frame 4 by its own weight, corresponds to the predetermined pressure that converts the pipe pressure release lid of the present invention from a closed state to an open state. [Example]

[0049] In the drain pipe ventilation equipment 1 of Example 2, the pressure release lid 17 attached to the upper opening lid 3 and the pipe pressure release lid 22 attached to the drain lid 5 are made of resin, and the weight of the pipe pressure release lid 22 is made heavier than the pressure release lid 17. Since the pressure release lid 17 is made of resin, it is lighter than the metal upper opening lid 3, and similarly, the pipe pressure release lid 22 is lighter than the metal drain lid 5. Here, the pressure release lid 17 and the pipe pressure release lid 22 are preferably made of a thermoplastic resin, and more specifically, those made of a hard polyvinyl chloride resin can be used.

[0050] As described above, the pipe pressure release lid 22 is made of resin and is therefore lighter than the pipe pressure release lid 22 of the first embodiment described above. Therefore, the pipe pressure release lid 22 can be raised from the closed state to the open state at a pressure lower than that of the first embodiment. Similarly, the pressure release lid 17 can also be raised from the closed state to the open state at a pressure lower than that of the first embodiment. That is, the configuration of the second embodiment can sequentially change the pipe pressure release lid 22 and the pressure release lid 17 to the open state when the internal pressure of the drain pipe reaches a pressure lower than that of the first embodiment, thereby preventing the internal pressure of the drain pipe from increasing.

[0051] The configuration of Example 2 is the same as that of Example 1 described above, except that the pressure release lid 17 and the tube pressure release lid 22 are made of resin and the tube pressure release lid 22 is made heavier than the pressure release lid 17. Therefore, the same components are denoted by the same symbols and their explanations are omitted.

[0052] In the drain pipe ventilation equipment 1 of Example 2, when the internal pressure of the drain pipe increases due to heavy rain or the like, the internal pressure causes the pipe pressure release lid 22 to rise and open the pipe pressure release port 21 (see FIG. 4(A)). As a result, the internal pressure of the internal space 13 of the drainage frame 2 increases, and the internal pressure of the internal space 13 causes the pressure release lid 17 to rise and open the pressure opening 16 (see FIG. 4(B)), thereby releasing the internal pressure of the drain pipe to the outside. In this way, the configuration of Example 2 is capable of releasing the internal pressure of the drain pipe as the internal pressure increases, similar to Example 1 described above, but releases the internal pressure at a lower pressure (internal pressure of the drain pipe) than Example 1.

[0053] The configuration of the second embodiment achieves the same effects as the first embodiment. Furthermore, because the internal pressure of the drain pipe can be released at a lower pressure than in the first embodiment, the internal pressure of the drain pipe can be kept even lower, further reliably preventing damage to the drain pipe. Furthermore, in the second embodiment, the metal drain cover 5 is heavier than the pipe pressure release cover 22. This allows the drain cover 5 to be held in a closed state over the drain outlet 102 by the internal pressure of the drain pipe, while the pipe pressure release cover 22 alone can be stably and reliably raised. Similarly, the metal upper opening cover 3 is heavier than the pressure release cover 17. This allows the internal pressure of the inner space 13 of the drain frame 2 to be stably and reliably raised over the upper opening 11 by the internal pressure of the drain frame 2. As a result, the sequential opening of the pipe pressure release port 21 and the pressure opening 16 can be more smoothly achieved by increasing the internal pressure of the drain pipe. [Example]

[0054] The drain pipe ventilation equipment 31 of the third embodiment has the function of releasing the internal pressure that has increased in the drain pipe to the outside (to the atmosphere) and the function of eliminating the negative pressure that has developed in the drain pipe, and is arranged to cover the upper end of the vertical pipe 101, as shown in Figure 5. This drain pipe ventilation equipment 31 includes the same drain frame 2 as in the first embodiment described above, an upper opening lid 33 that closes the upper opening 11 of the drain frame 2, a lid receiving frame 4 attached to the drain outlet portion 102 of the vertical pipe 101, a support plate 35 attached to the lid receiving frame 4, and a pressure transmission cylinder 32 attached to the support plate 35.

[0055] The drainage frame 2 has the upper opening 11 that is closed by the upper opening lid 33, and has an engagement portion 37 on the inside of the upper opening 11 that engages with a lifting rod portion 41 provided on the upper opening lid 33. The drainage frame 2 of Example 3 has the same configuration as Example 1 except for the engagement portion 37.

[0056] 5 and 6 , the upper opening lid 33 includes a main lid portion 42 having an opening 49 penetrating therethrough in the vertical direction, the lift rod 41 tiltably mounted on the main lid portion 42, a support portion 43 fixed to the opening 49 of the main lid portion 42, and a cover portion 44 covering the opening of the main lid portion 42 and the support portion 43. The main lid portion 42 has a cylindrical wall portion (not shown) that protrudes downward and forms the opening 49. When the upper opening lid 33 is closed, the upper opening 32a of the pressure-voltage cylinder 32 (described later) surrounds and is in close contact with the wall portion. The cover portion 44 also has a vent hole 45, which communicates with the opening 49 of the main lid portion 42 via a storage space 47 formed by the cover portion 44 and the support portion 43. That is, when the upper opening lid 33 is attached to the upper opening 11 of the drainage frame 2, the inner space 13 of the drainage frame 2 is connected to the outside (atmosphere) through the opening 49, the storage space 47, and the ventilation port 45.

[0057] A vent hole closing cover 46 that closes the vent hole portion 45 is arranged so as to be movable up and down in the storage space 47 of the upper opening lid 33. The vent hole closing cover 46 is biased upward by a coil spring 40 provided in the storage space 47, and is normally held in a closed state in which the vent hole portion 45 is closed by the biasing force of the coil spring 40.

[0058] The lifting rod 41 engages with the engaging portion 37 of the drainage frame 2, and enables the upper opening lid 33 to be converted between a closed state in which it is attached to the upper opening 11 of the drainage frame 2, and an open state in which it is raised from the closed state to open the upper opening 11. When the lifting rod 41 and the engaging portion 37 are engaged, the upper opening lid 33 cannot be detached from the drainage frame 2. This prevents the upper opening lid 33 from being blown upward when strong pressure acts on the upper opening lid 33 from the internal space 13 of the drainage frame 2.

[0059] A lid receiving frame 4 similar to that of the first embodiment is disposed in the drain outlet portion 102 of the vertical pipe 101, and the support plate 35 is attached to the lid receiving frame 4. The support plate 35 is provided with a cylindrical flange portion 38 that penetrates in the vertical direction, and the inside of the vertical pipe 101 (the drain outlet portion 102) communicates with the inner space 13 of the drain frame 2 via the flange portion 38. Here, the inner diameter of the flange portion 38 is smaller than the inner diameter of the drain outlet portion 102. In addition, in the third embodiment, the flange portion 38 is always open, and therefore the flange portion 38 essentially corresponds to an opening that opens the vertical pipe 101 upward.

[0060] The pressure transmission cylinder 32 is a generally cylindrical body formed in a bellows shape in the vertical direction. Its lower end is fitted onto the flange portion 38 of the support plate 35 and sealed thereto, with an upper opening 32a that opens upward as a free end. The pressure transmission cylinder 32 is made of an elastically deformable resin and is expandable and contractible in the vertical direction. With the upper opening lid 33 attached to the upper opening 11 of the drainage frame 2, the pressure transmission cylinder 32 is elastically contracted downward by the upper opening lid 33, so that the upper opening 32a of the pressure transmission cylinder 32 is tightly fitted to the upper opening lid 33. In this state, the upper opening 32a of the pressure transmission cylinder 32 is closed by the upper opening lid 33, so that the interior of the pressure transmission cylinder 32 is connected to the interior of the vertical pipe 101 (the drain outlet 102) and is closed to prevent water from passing through the inner space 13 of the drainage frame 2. Here, the upper end opening 32a of the pressure transmission cylinder 32 is tightly fitted around and surrounds the opening 49 of the upper opening lid 33. As a result, with the upper opening lid 33 attached to the upper opening 11, the inside of the vertical pipe 101 (drain outlet portion 102) communicates with the storage space 47 via the opening 49 of the upper opening lid 33, and the internal pressure of the drain pipe acts on the upper opening lid 33 (opening 49) and the vent hole closing lid 46.

[0061] In this embodiment 3, the main cover portion 42, the lifting rod portion 41, the support portion 43, the covering portion 44, and the vent hole closing cover 46 that constitute the upper opening cover 33 are made of metal (preferably a metal used in cast products, more preferably cast iron) as in the case of embodiment 1. The support plate 35 is also made of a similar metal. In addition, the pressure transmission cylinder 32 is preferably made of resin (preferably a thermoplastic resin).

[0062] Next, the operation of the drain pipe ventilation system 31 of the third embodiment will be described. In the normal state, as shown in Figure 5, the upper opening lid 33 is attached to the upper opening 11 by its own weight and is held in a closed state, and the vent closing lid 46 of the upper opening lid 3 is held in a closed state over the vent portion 45 by the biasing force of the coil spring 40.

[0063] When the pressure inside the drain pipe drops and becomes negative, this negative pressure acts on the vent hole closing cover 46 via the vertical pipe 101 and the pressure transmission cylinder 32. When this negative pressure becomes greater than the upward biasing force (elastic force) of the coil spring 40, the vent hole closing cover 46 moves down against the biasing force of the coil spring 40, as shown in Figure 6, and the vent portion 45 is opened. This connects the inside of the drain pipe to the outside, thereby releasing the negative pressure in the drain pipe. Note that the negative pressure also acts on the upper opening cover 33, but since the upper opening cover 33 is supported so that it cannot move downward below the closed state of the upper opening 11, it is maintained in this closed state.

[0064] When the negative pressure in the drain pipe is released by opening the vent port 45, the vent port closing cover 46 rises due to the biasing force of the coil spring 40, closing the vent port 45. This returns the device to the normal state described above (FIG. 5).

[0065] Here, in order to change the vent closing cover 46 from the closed state to the open state, a force is required to elastically compress the coil spring 40, and therefore the negative pressure in the drain pipe that changes the vent closing cover 46 to the open state is determined according to the elastic force (elastic coefficient) of the coil spring 40. In other words, the elastic force of the coil spring 40 can be set based on the limit (threshold) of the negative pressure generated in the drain pipe.

[0066] On the other hand, when the internal pressure of the drain pipe increases due to heavy rain or the like, the internal pressure acts on the upper opening lid 33 via the vertical pipe 101 and the pressure transmission cylinder 32. When this internal pressure exceeds the pressure required to lift the upper opening lid 33, the upper opening lid 33 lifts from the closed state to the open state, as shown in Figure 7. As a result, the upper opening lid 33 moves upward above the upper end of the pressure transmission cylinder 32, opening the upper end opening 32a of the pressure transmission cylinder 32 and also opening the upper opening 11 of the drainage frame 2. This opens the inside of the drain pipe to the outside, and the internal pressure of the drain pipe is released. Note that the internal pressure of the drain pipe also acts on the vent hole closing lid 46, but because the vent hole closing lid 46 cannot move upward relative to the upper opening lid 33, the vent hole portion 45 is kept closed.

[0067] When the internal pressure of the drain pipe is reduced by the opening of the upper opening 11 and the upper end opening 32a of the pressure transmission cylinder 32, the upper opening lid 33 descends under its own weight and fits onto the upper opening 11 of the drain frame 2, closing it. As a result, the upper end of the pressure transmission cylinder 32 comes into tight contact with the upper opening lid 33, closing the upper end opening 32a. This returns the system to its normal state (Fig. 5).

[0068] Here, in order to change the upper opening lid 33 from a closed state to an open state, pressure is required to lift the upper opening lid 33, and therefore the internal pressure of the drain pipe that changes the upper opening lid 33 to an open state is determined according to the weight of the upper opening lid 33. In other words, the weight of the upper opening lid 33 can be set based on the upper limit (threshold) of the internal pressure of the drain pipe.

[0069] The drain pipe ventilation system 31 of the third embodiment includes an upper opening cover 33 that converts the upper opening 11 of the drain frame 2 between a closed state and an open state, a vent closing cover 46 that opens the vent opening 45 using negative pressure in the drain pipe, and a pressure transmission cylinder 32 that directly transmits drain pipe pressure to the upper opening cover 33 and the vent closing cover 46 in the interior space 13 of the drain frame 2. With this configuration, when negative pressure occurs in the drain pipe, the negative pressure acts on the vent closing cover 46 via the pressure transmission cylinder 32, causing the vent closing cover 46 to move downward and open the vent opening 45. Because the negative pressure in the drain pipe can be applied directly to the vent closing cover 46, the negative pressure can stably convert the vent closing cover 46 to an open state. This eliminates negative pressure in the drain pipe.

[0070] Furthermore, when the internal pressure of the drain pipe increases, this internal pressure acts on the upper opening lid 33 via the pressure transmission cylinder 32, causing the upper opening lid 33 to rise, opening the upper opening 11 and the upper end opening 32a of the pressure transmission cylinder 32. In this way, the internal pressure of the drain pipe can be made to act directly on the upper opening lid 33, so that the increase in internal pressure can stably convert the upper opening lid 33 to an open state. This prevents the internal pressure of the drain pipe from increasing, and prevents the drain pipe from being damaged by the increase in internal pressure.

[0071] Furthermore, in the configuration of the present embodiment 3, the drain outlet portion 102 (inside the drain pipe) of the vertical pipe 101 is closed by the pressure transmission cylinder 32 within the drainage frame 2 to prevent water from passing through. This makes it possible to prevent rainwater that has entered the inner space 13 of the drainage frame 2 through gaps in the upper opening lid 33, etc., from flowing into the drain pipe. This makes it possible to prevent rainwater that has entered the inner space 13 from flowing into the drain pipe, thereby preventing an increase in the burden on drainage treatment.

[0072] In the configuration of Example 3, when viewed from the perspective of the drain pipe negative pressure relieving function, the vent portion 45, vent port closing cover 46, and coil spring 40 correspond to the vent port opening means of the present invention, and the pressure transmission cylinder 32 corresponds to the pressure transmission means of the present invention. The negative pressure in the drain pipe that moves the vent port closing cover 46 down corresponds to the pressure that converts the vent port closing cover of the present invention to an open state (pressure acting on the vent port closing cover). On the other hand, in terms of the drain pipe internal pressure release function, the upper opening lid 33 corresponds to the vent hole closing lid of the present invention. The upper opening 11, the upper opening lid 33, and the lifting rod 41 correspond to the vent hole opening means of the present invention, and the pressure transmission cylinder 32 corresponds to the pressure transmission means of the present invention. Furthermore, the internal pressure of the drain pipe that lifts the upper opening lid 33 corresponds to the predetermined pressure that lifts the vent hole closing lid of the present invention and changes it to the open state. [Example]

[0073] The drain pipe ventilation equipment 51 of the fourth embodiment has the function of eliminating negative pressure generated in the drain pipe, and is disposed so as to cover the upper end of the vertical pipe 101, as shown in Fig. 8. As with the third embodiment described above, this drain pipe ventilation equipment 51 includes a drain frame 2, an upper opening lid 53, a lid receiving frame 4, a support plate 35, and a pressure transmission cylinder 52. Here, other than the upper opening lid 53 and the pressure transmission cylinder 52, the configuration is the same as that of the third embodiment.

[0074] As shown in Figures 8 and 9, the upper opening lid 53 comprises a main lid portion 62 that is attached to the upper opening 11 of the drainage frame 2, and a small lid portion 64 that is attached to the mounting opening 63 of the main lid portion 62. The main lid portion 62 is provided with the mounting opening 63 that penetrates in the vertical direction, and is further provided with the lifting rod portion 41 similar to that of Example 3. The small lid portion 64 is attached to the mounting opening 63 of the main lid portion 62 to close the mounting opening 63, and can be opened by lifting it upward relative to the main lid portion 62. The small lid portion 64 is provided with a cylindrical tube wall portion (not shown) that forms an opening 65 that penetrates in the vertical direction, and is provided with a support portion 43 fixed to the opening 65, and a covering portion 44 that covers the opening 65 and the support portion 43. A vent hole portion 45 formed in the covering portion 44 is in communication with the opening 65 via a storage cavity 47 formed between the covering portion 44 and the support portion 43. Furthermore, the storage cavity 47 is provided with a vent hole closing cover 46 that closes the vent hole portion 45, and a coil spring 40 that keeps the vent hole closing cover 46 in a closed state. The support portion 43, covering portion 44, storage cavity 47, vent hole portion 45, vent hole closing cover 46, and coil spring 40 have the same configuration as in the third embodiment described above.

[0075] The pressure transmission cylinder 52 is formed from a soft cylindrical sheet and is disposed in the inner space 13 of the drainage frame 2. The lower end of this pressure transmission cylinder 52 is fitted onto the flange portion 38 of the support plate 35 and tightly fixed thereto, and the upper end is surrounded by and tightly fixed to the cylindrical wall portion that forms the opening 65 of the upper opening lid 53. The pressure transmission cylinder 52 connects the drain outlet 102 of the vertical pipe 101 with the opening 65 of the upper opening lid 33. This allows the pressure inside the drain pipe to act on the vent hole closing cover 46 of the upper opening lid 53 via the pressure transmission cylinder 52.

[0076] In the drain pipe ventilation system 51 of Example 4, in its normal state, the upper opening lid 53 is attached to the upper opening 11 and held in a closed position, as shown in FIG. 8 , and the vent closing lid 46 is held in a closed position over the vent opening 45 by the biasing force of the coil spring 40. As shown in FIG. 9 , when the negative pressure generated in the drain pipe exceeds the biasing force (elastic force) of the coil spring 40, the negative pressure acting on the vent closing lid 46 via the vertical pipe 101 and the pressure transmission cylinder 52 causes the vent closing lid 46 to move downward, opening the vent opening 45. This connects the inside of the drain pipe to the outside, thereby releasing the negative pressure in the drain pipe. After this, when the negative pressure in the drain pipe is released, the vent closing lid 46 moves upward by the biasing force of the coil spring 40, closing the vent opening 45. This returns the system to the normal state ( FIG. 8 ).

[0077] The drain pipe ventilation equipment 51 of the fourth embodiment maintains communication between the opening 65 of the upper opening lid 53 and the drain outlet 102 (inside the drain pipe) of the vertical pipe 101 by a pressure transmission cylinder 52 connected to the upper opening lid 53 and the support plate 35. With this configuration, when negative pressure occurs in the drain pipe, the negative pressure acts directly on the vent hole closing lid 46 via the pressure transmission cylinder 52, as in the third embodiment described above, and the vent hole closing lid 46 is lowered to open the vent hole 45. In this way, the negative pressure in the drain pipe can stably switch the vent hole closing lid 46 to an open state, thereby eliminating the negative pressure in the drain pipe.

[0078] Furthermore, as in the above-mentioned third embodiment, the pressure transmission cylinder 52 closes the drain outlet portion 102 (inside the drain pipe) of the vertical pipe 101 so that water cannot pass through, thereby preventing rainwater that has entered through gaps in the upper opening lid 53, etc., from flowing into the drain pipe, thereby preventing an increase in the burden of drainage treatment.

[0079] Furthermore, the pressure transmission cylinder 52 is made of a cylindrical sheet made of soft vinyl chloride resin, and is therefore extendable. This has the excellent advantage of allowing the pressure transmission cylinder 52 to be extended when opening the small lid portion 64 of the upper opening lid 53, for example, during inspection, making the work easier and more efficient. The pressure transmission cylinder 52 is not limited to being made of soft vinyl chloride resin, and any soft resin can be used, with soft thermoplastic resin being preferred.

[0080] In the configuration of Example 4, the vent portion 45, the vent closing cover 46, and the coil spring 40 correspond to the vent opening means of the present invention, and the pressure transmission cylinder 52 corresponds to the pressure transmission means of the present invention. The negative pressure of the drain pipe that moves the vent closing cover 46 down corresponds to the pressure that changes the vent closing cover of the present invention to the open state (the pressure acting on the vent closing cover). [Example]

[0081] The drain pipe ventilation equipment 71 of the fifth embodiment has the function of releasing the internal pressure that has increased in the drain pipe to the outside (atmosphere), and is arranged to cover the upper end of the vertical pipe 101, as shown in Figure 10. This drain pipe ventilation equipment 71 includes a drain frame 2, an upper opening lid 73, a lid receiving frame 4, a drain outlet lid 75, and a pressure transmission cylinder 32. Here, apart from the upper opening lid 73 and the drain outlet lid 75, the configuration is the same as that of the third embodiment described above.

[0082] The upper opening lid 73 is attached to the upper opening 11 of the drainage frame 2 to close the upper opening 11, and is provided with the lifting rod 41 similar to that of Example 3. As in Example 3 described above, this upper opening lid 73 can be converted between a closed state in which it is attached to the upper opening 11 of the drainage frame 2 and an open state in which it is lifted from the closed state to open the upper opening 11 by engaging the lifting rod 41 with the engaging portion 37 of the drainage frame 2, and in this engaged state it cannot be detached from the drainage frame 2. The upper opening lid 73 of Example 5 is configured not to have a vent portion or vent closing lid as in Examples 3 and 4.

[0083] The drain outlet lid 75 is attached to the lid receiving frame 4 disposed in the drain outlet portion 102 of the vertical pipe 101 to close the drain outlet portion 102. The drain outlet lid 75 is provided with a cylindrical flange portion 78 with a top and a pipe pressure release lid 81 that closes the pipe pressure release port 79 of the flange portion 78. The pipe pressure release port 79 is formed by vertically penetrating the ceiling portion of the flange portion 78, and connects the inner space 13 of the drain frame 2 with the drain outlet portion 102 of the vertical pipe 101. Furthermore, the ceiling portion of the flange portion 78 is provided with a lid receiving portion 82 to which the pipe pressure release lid 81 is attached, and when the pipe pressure release lid 81 is attached to the lid receiving portion 82 (hereinafter referred to as the closed state), the pipe pressure release port 79 is closed by the pipe pressure release lid 81. When the pipe pressure release lid 81 is raised and the pipe pressure release port 79 is open (hereinafter referred to as the open state), the interior of the vertical pipe 101 communicates with the inner space 13 of the drainage frame 2 (FIG. 11(A)). The pipe pressure release lid 81 is maintained in a closed state in which it is attached to the lid receiving portion 82 of the drainage port lid 75 by its own weight, and is raised from the closed state to an open state when it is lifted upward. Then, when this lifting force is released, it is lowered from the open state to a closed state.

[0084] The pipe pressure release lid 81 is configured to include a main lid portion (not shown) that is attached to the lid receiving portion 82 of the drain outlet lid 75, and a pressure receiving shaft portion (not shown) that is inserted into the pipe pressure release port portion 79 and protrudes downward. The drain outlet lid 75 can also be provided with a locking member similar to that of the drain lid 5 of the first embodiment described above.

[0085] The pressure transmission cylinder 32 has the same structure as in the third embodiment, with its lower end fitted onto the flange 78 of the drain outlet lid 75 and tightly fixed thereto, and its upper opening 32a being a free end. With the upper opening lid 73 attached to the upper opening 11 of the drain frame 2, the pressure transmission cylinder 32 is elastically compressed downward by the upper opening lid 73, so that the upper opening 32a of the pressure transmission cylinder 32 is in tight contact with the upper opening lid 73.

[0086] Next, the operation of the drain pipe ventilation system 71 of the fifth embodiment will be described. In the normal state, as shown in Figure 10, the upper opening lid 73 is attached to the upper opening 11 of the drainage frame 2 by its own weight and is kept in a closed state, and the pipe pressure release lid 81 is attached to the pipe pressure release opening portion 79 of the drain outlet lid 75 by its own weight and is kept in a closed state.

[0087] When the internal pressure of the drain pipe increases due to heavy rain or the like, the internal pressure acts on the pipe pressure release cover 81 through the vertical pipe 101. When this internal pressure exceeds the pressure required to lift the pipe pressure release cover 81, the pipe pressure release cover 22 rises from the closed state to the open state, as shown in Figure 11 (A). As a result, the internal pressure of the drain pipe is released into the pressure transmission cylinder 32 through the pipe pressure release port 79, and acts on the upper opening cover 73 through the pressure transmission cylinder 32.

[0088] Thereafter, when the internal pressure of the pressure transmission cylinder 32 exceeds the pressure required to lift the upper opening lid 73, the upper opening lid 73 rises and is converted to an open state, as shown in Figure 11(B) . As a result, the upper opening lid 73 moves upward above the upper end opening 32a of the pressure transmission cylinder 32, opening the upper end opening 32a and also opening the upper opening 11 of the drainage frame 2, so that the inside of the drainage pipe communicates with the outside and the internal pressure of the drainage pipe is released.

[0089] When the internal pressure of the drain pipe is reduced by the opening of the upper opening 11 and the upper end opening 32a of the pressure transmission cylinder 32, the upper opening lid 73 moves down under its own weight and fits onto the upper opening 11, closing it, and the pipe pressure release lid 22 moves down under its own weight and closes the pipe pressure release port 79. This returns the pipe to its normal state (Fig. 10).

[0090] In this fifth embodiment, similarly to the first and third embodiments described above, the weight of the pipe pressure release lid 22 and the weight of the upper opening lid 73 can be set based on the upper limit (threshold) of the internal pressure of the drain pipe.

[0091] The drain pipe ventilation equipment 71 of the fifth embodiment includes a drain outlet cover 75 that closes the drain outlet 102 of the vertical pipe 101, a pipe pressure release port 79, and a pipe pressure release cover 81. The drain outlet cover 75 also includes a pressure transmission cylinder 32 that allows the internal pressure of the vertical pipe 101 to directly act on the upper opening cover 73 when the pipe pressure release cover 81 is open. With this configuration, when the internal pressure of the drain pipe increases, the pipe pressure release port 79 opens, and the internal pressure transmitted from the drain pipe to the pressure transmission cylinder 32 opens the upper opening 11. In this way, when the pipe pressure release port 79 is open, the pressure transmission cylinder 32 can directly act on the upper opening cover 73, thereby stably switching the upper opening cover 73 to an open state. This prevents the internal pressure of the drain pipe from increasing, thereby preventing damage to the drain pipe due to the increased internal pressure.

[0092] Furthermore, the configuration of the fifth embodiment makes the inside of the pressure transmission cylinder 32 in the drainage frame 2 watertight. This prevents rainwater that has entered the internal space 13 of the drainage frame 2 through gaps in the upper opening lid 73, etc., from accumulating on the pipe pressure release lid 81, thereby preventing the pipe pressure release lid 81 from becoming unable or difficult to lift due to the water pressure of the water accumulated in the internal space 13, and allowing the pipe pressure release lid 81 to be stably lifted by an increase in the internal pressure of the drainage pipe. Thus, the configuration of the fifth embodiment stably performs the function of relieving the internal pressure of the drainage pipe.

[0093] In the configuration of this fifth embodiment, the upper opening lid 73 corresponds to the vent hole closing lid of the present invention. The upper opening 11, the upper opening lid 73, and the lifting rod portion 41 correspond to the vent hole opening means of the present invention, and the pressure transmission cylinder 32 corresponds to the pressure transmission means of the present invention. The drain outlet lid 75, the pipe pressure release port portion 79, and the pipe pressure release lid 81 correspond to the pipe pressure release means of the present invention. Furthermore, the internal pressure of the drain pipe that lifts the pipe pressure release lid 81 corresponds to the predetermined pressure that converts the pipe pressure release lid of the present invention to an open state, and the internal pressure of the pressure transmission cylinder 32 that lifts the upper opening lid 73 corresponds to the predetermined pressure that lifts the vent hole closing lid of the present invention and converts it to an open state.

[0094] The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, the dimensions and shapes of the components in the above-described embodiments can be modified as needed.

[0095] In the configuration of Example 2, the upper opening lid and the drainage lid may be made of resin, like the pressure release lid and the pipe pressure release lid. Even in this case, it is preferable that the pressure release lid is lighter than the upper opening lid, the pipe pressure release lid is lighter than the drainage lid, and the pressure release lid is lighter than the pipe pressure release lid. In addition, in the configurations of Examples 1 and 2, as long as the weight relationship between the upper opening lid, the pressure release lid, the drainage lid, and the pipe pressure release lid is maintained, the molding material can be appropriately selected and applied, not limited to metal (cast iron) or resin. Similarly, the molding material can be appropriately selected and applied to the configurations of Examples 3 to 5.

[0096] In the configurations of Examples 1 and 2, the upper opening lid is provided with a pressure opening and a pressure release lid. However, this is not limited to this, and the upper opening lid can also function as a pressure release lid. Specifically, the upper opening lid of Example 5 is used instead of the upper opening lid of Examples 1 and 2. In this configuration, the upper opening of the drainage frame corresponds to the pressure opening of the present invention, and the upper opening lid corresponds to the pressure release lid of the present invention. The upper opening, the upper opening lid, and the lifting rod of the upper opening lid correspond to the first pressure release means of the present invention. With this configuration, when the pipe pressure release port portion is opened due to an increase in internal pressure of the drainage pipe, the internal pressure of the drainage frame increases, and the upper opening lid is raised and opened. As a result, the internal pressure of the drainage pipe can be released to the outside, as in Examples 1 and 2.

[0097] In the configuration of the third embodiment, the drain pipe has both the function of releasing the internal pressure that has increased in the drain pipe and the function of releasing the negative pressure that has occurred in the drain pipe, but this is not limited to this, and the configuration may also have only the function of releasing the internal pressure that has increased in the drain pipe. This configuration can be implemented by replacing the upper opening lid of the third embodiment with an upper opening lid similar to that of the fifth embodiment.

[0098] The configuration of Example 5 has the function of relieving internal pressure built up in the drain pipe, but in addition to this function, it can also be configured to have the function of relieving negative pressure generated in the drain pipe. In this configuration, the upper opening lid of Example 3 is applied instead of the upper opening lid of Example 5. The pipe pressure release lid provided on the drain outlet lid is provided with a structure similar to the vent portion, storage space, vent hole closing lid, and coil spring provided on the upper opening lid of Example 3. As a result, when negative pressure occurs in the drain pipe, the vent hole closing lid provided on the pipe pressure release lid of the drain outlet lid descends to open the vent portion, which in turn opens the vent hole opening lid of the upper opening lid, thereby relieving the negative pressure. [Explanation of symbols]

[0099] 1, 31, 51, 71 Drainage pipe ventilation equipment 2 Drainage frame 3,53,73 Top opening lid 5 Drain lid 11 Top opening 13 Inner cavity 16 Pressure Opening 17 Pressure Relief Lid 21,79 Pipe pressure release port 22,81 Pipe pressure release lid 32,52 Pressure transmission cylinder 45 Ventilation port 46 Vent Closure Cover 102 Drain port

Claims

1. a drainage frame having an upper opening that opens upward and an inner space that communicates with the inside of a drainage pipe via a drain outlet provided below the upper opening; and an opening lid device that is disposed in the upper opening and covers the upper opening; a drain cover device disposed at the drain outlet portion and covering the drain outlet portion; The device is provided with: The opening lid device is a pressure release lid that can be changed between a closed state that closes the internal space of the drainage frame and an open state that is raised from the closed state to open the internal space, and a first pressure release means that changes the pressure release lid from the closed state to the open state by the internal pressure of the drainage frame when the internal pressure of the drainage frame reaches a predetermined pressure or higher; The drain lid device is A drain pipe ventilation system characterized in that it is equipped with a pipe pressure release cover that can be converted between a closed state that closes the drain pipe and an open state that is raised from the closed state to open the drain pipe, and is equipped with a second pressure release means that, when the internal pressure of the drain pipe reaches a predetermined pressure or higher, causes the pipe pressure release cover to convert from the closed state to the open state due to the internal pressure of the drain pipe.

2. 2. The drain pipe ventilation system according to claim 1, wherein the weight of the pipe pressure release cover is heavy compared to the weight of the pressure release cover.

3. The drain cover device is a drain cover for closing the drain outlet; The drain cover has a pipe pressure release port formed to communicate with the inside of the drain pipe and the inner space of the drain frame, and the pipe pressure release cover is attached to the pipe pressure release port so as to be movable up and down. The pipe pressure release port is closed when the pipe pressure release lid is in a closed state, and the pipe pressure release port is opened when the pipe pressure release lid is in an open state, 2. The drain pipe ventilation equipment according to claim 1, wherein the weight of the pipe pressure release lid is lighter than the weight of the drain lid and heavier than the weight of the pressure release lid of the opening lid device.

4. A drainage frame body has an upper opening that opens upward and an inner space that communicates with the inside of a drainage pipe via a drain outlet portion provided below the upper opening, and is provided with an opening lid device that is disposed at the upper opening and covers the upper opening, The opening lid device is a vent closing cover that can be changed between a closed state that closes the internal space of the drainage frame and an open state that opens the internal space by being raised or lowered from the closed state, and a vent opening means that changes the vent closing cover from the closed state to the open state by pressure acting on the vent closing cover; Furthermore, a pressure transmission means is provided in the inner space of the drainage frame, and prevents water from entering the drain pipe at least when the vent closing cover is closed, and applies pressure generated inside the drain pipe to the vent closing cover, A drain pipe ventilation system characterized in that the vent closing cover is converted into an open state by pressure acting on the vent closing cover via the pressure transmission means.

5. The vent opening means of the opening cover device is When a pressure equal to or greater than a predetermined pressure acts on the vent hole closing cover from below, the vent hole closing cover is raised and converted into an open state, The pressure transmitting means is a water-impermeable pressure transmission cylinder whose lower end is connected to the inside of the drain pipe and whose upper end is in close contact with the vent hole closing cover when the vent hole closing cover is closed, and which is spaced apart from the vent hole closing cover when the vent hole closing cover is open; A drain pipe ventilation equipment as described in claim 4, characterized in that when the vent closing cover is closed, the internal pressure of the drain pipe acts on the vent closing cover through the pressure transmission cylinder, thereby converting the vent closing cover to an open state.

6. The pressure transmission cylinder is It is made of an elastic material and expands and contracts by elastic deformation in the vertical direction. The drain pipe ventilation equipment according to claim 5, characterized in that when the vent closing cover is closed, it is elastically compressed by the weight acting from the vent closing cover, so that the upper end is tightly contacted with the vent closing cover.

7. The drain cover device is disposed at the drain outlet and covers the drain outlet, The drain lid device is A drain pipe ventilation equipment as described in claim 5 or claim 6, characterized in that it is equipped with a pipe pressure release cover that can be converted between a closed state that closes the drain outlet and an open state that is raised from the closed state to open the drain outlet, and is equipped with pipe pressure release means that, when the internal pressure of the drain pipe reaches a predetermined pressure or higher, causes the pipe pressure release cover to convert from the closed state to the open state due to the internal pressure of the drain pipe.

8. The opening lid device is an upper opening lid that closes the upper opening; The upper opening cover has a vent portion formed to communicate the inner space of the drainage frame with the outside, and a vent closing cover arranged to be movable up and down. The vent opening is closed when the vent closing cover is in a closed state, and the vent opening is opened when the vent closing cover is lowered from the closed state, The pressure transmitting means is a water-impermeable pressure transmission cylinder that communicates between the drain port and the vent port; A drain pipe ventilation system as described in claim 4, characterized in that negative pressure generated inside the drain pipe acts on the vent closing cover through the pressure transmission cylinder, thereby converting the vent closing cover to an open state.

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