JPH07252874A - Ventilating device - Google Patents

Abstract

PURPOSE:To simplify the structure, increase the ventilation capacity, and provide specifications for both intake and exhaust, for, only exhaust, or only intake with the same basic structure in a ventilating device keeping the pressure in a drain pipe at the same state as the atmospheric pressure, capable of preventing the floating or blowing-off of the cover of an inspecting/cleaning pipe or the breakup of the reservoir water in a trap. CONSTITUTION:A ventilation pipe main body 12 is divided into the first ventilation path 23 and the second ventilation path 24 by a partition 12D provided at its center section, and a semicircular exhaust valve 14 is fitted to each of the semicircular inside vent holes 16 of the first ventilation path 23 and the second ventilation path 24 respectively. A semicircular intake valve 15 is fitted to each of the semicircular outside vent holes 17 of the first ventilation path 23 and the second ventilation path 24 respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ventilator for ventilating a drainage pipe.

[0002]

2. Description of the Related Art Conventionally, sewage discharged from homes has been drained into rivers along with rainwater through drains.
With the spread of sewers, sewage and rainwater have come to be separated, and only rainwater flows into rivers, and sewage is sent to wastewater treatment plants through underground drains.

As the drainage pipe, concrete pipes have been widely used until now, but recently, synthetic resin pipes have become popular. Along with this, lids and the like used for inspection / cleaning pipes for drainage pipes are also shifting from those made of concrete or cast iron to those made of synthetic resin.

The above-mentioned synthetic resin drain pipes and lids are superior in watertightness to conventional ones, but are light in weight, so that the following new problems occur.

That is, for example, when drainage of laundry, bath water, etc. are discharged simultaneously from each house in an apartment house, a large amount of dirty water flows in the drain pipe at once, and the air existing in front of the dirty water is discharged. The pressure rises momentarily. Then, due to the high watertightness of the drainage pipe, the influence of the pressure of the air directly reaches the lid of the inspection / cleaning pipe, thereby,
The lid was easily lifted from the opening of the inspection / cleaning tube or blown off.

Further, the pressure of the air existing behind the wastewater flowing through the drainage pipe at once decreases momentarily, and the accumulated water in the trap for preventing odors communicating with the drainage pipe breaks ( Sucked into the drain). Then, the inside of the drainage pipe and the inside of the building are directly communicated with each other, and there is a problem that a bad odor in the drainage pipe enters the inside of the building.

Therefore, conventionally, the lid of the inspection / cleaning pipe is prevented from being lifted up or blown off when the pressure in the drainage pipe is temporarily increased, and the pressure in the drainage pipe is temporarily lowered. In order to prevent the stored water from being broken, the intake / exhaust valve device for a drain pipe described in JP-A No. 4-7433 is proposed. This intake / exhaust valve device is integrally provided with an exhaust valve for discharging the air in the drain pipe to the outside and an intake valve for introducing the outside air into the drain pipe.

According to this conventional technique, the exhaust valve and the intake valve are actuated in response to pressure fluctuations in the drainage pipe, the pressure in the drainage pipe is kept at the same level as the atmospheric pressure, and the lid of the inspection / cleaning pipe is lifted up. It is possible to prevent blowout or breakage of accumulated water in the trap.

[0009]

However, in the prior art, the intake / exhaust valve device is attached to the ventilation pipe communicating with the drain pipe, and this intake / exhaust valve device includes a canopy portion, a tubular body,
It is composed of a combination of an intake / exhaust valve unit, an exhaust valve, and an intake valve.In particular, the intake / exhaust valve unit has an exhaust passage and an intake passage separated from each other by a complicated partition wall. is there.

Further, in the prior art, the intake and exhaust valve units provided in the cross section of the ventilation pipe are provided with the exhaust ventilation port and the intake ventilation port which are significantly smaller than the cross section of the ventilation pipe. Therefore, the intake and exhaust capacity is small.

Further, in the prior art, although a single intake / exhaust valve device is integrally provided with an exhaust valve and an intake valve, and installation on the exhaust pipe is convenient, a valve device for exhaust only or intake only is provided. If required, it is necessary to provide a completely separate valve device.

Further, in the prior art, since the valve seat surface of the intake / exhaust valve is set horizontally, the condensed water collects on this valve seat surface and freezes it so that the valve and the valve seat come into close contact with each other. There is a risk of malfunctioning of.

The present invention is a ventilation device capable of keeping the pressure in the drainage pipe at the same level as the atmospheric pressure and preventing the lid of the inspection / cleaning pipe from being lifted or blown off, or the water in the trap being broken. In addition, the ventilation capacity has been increased and the basic configuration has been made the same for both intake and exhaust, exclusive for exhaust,
It is an object of the present invention to provide a ventilation device that can be divided into specifications only for intake.

It is another object of the present invention to prevent freezing of dew condensation water around the valve seat and prevent malfunction of the valve.

[0015]

According to a first aspect of the present invention, there is provided a ventilation device having a ventilation valve provided in a ventilation pipe, wherein a ventilation cover is provided around an opening of a ventilation pipe body, and a central portion of the opening is provided. With the partition provided, the space inside the ventilation cover is divided into a first ventilation path and a second ventilation path, and the ventilation pipe communication part of the first ventilation path is made into a semicircular inner ventilation port, and the ventilation pipe of the first ventilation path is surrounded. The outer space communication part of is a semi-circular outer vent, the ventilation pipe communication part of the second ventilation path is a semi-circular inner ventilation hole, and the outer space communication part of the second ventilation path around the ventilation pipe is a semi-circular outer side. A semi-circular vent valve can be attached to each of the inner vents of the first vent passage and the second vent passage, and a semi-circular annular vent valve of the first vent passage and the second vent passage can be attached. It is adapted to be attached to each of the outer vents.

According to a second aspect of the present invention, in addition to the first aspect of the present invention, the semicircular shape is formed in an inner vent of one of the first vent passage and the second vent passage. An exhaust valve, which is a ventilation valve, is provided, and the exhaust valve is set to close when the internal pressure of the ventilation pipe is in a normal pressure state and to open when the internal pressure exceeds a certain positive pressure. An intake valve, which is the semicircular annular ventilation valve, is provided at the outer ventilation port of the other ventilation path of the ventilation path, and the intake valve closes when the internal pressure of the ventilation pipe is in a normal pressure state, and a constant negative pressure. It is designed so that it will be opened when it exceeds.

According to a third aspect of the present invention, in addition to the first aspect of the present invention, the semicircular vent valve is provided at each of the inner vents of the first vent passage and the second vent passage. An exhaust valve is provided, and the exhaust valve is set to close when the internal pressure of the ventilation pipe is in a normal pressure state and to open when the internal pressure of the ventilation pipe exceeds a certain positive pressure.

According to a fourth aspect of the present invention, in addition to the first aspect of the present invention, the semi-annular vent valve is provided at each of the outer vents of the first vent passage and the second vent passage. An intake valve is provided, and the intake valve is set to close when the internal pressure of the ventilation pipe is in a normal pressure state and to open when the internal pressure exceeds a certain negative pressure.

The present invention according to claim 5 is based on claims 1 to 4.
In any one of the present inventions, the valve seat surface of the ventilation valve is set to be inclined with respect to a horizontal plane.

[0020]

According to the present invention described in claims 1 to 4,
Has the effect of. When a large amount of sewage flows momentarily in the drainage pipe, the pressure of the air on the front side of the sewage increases temporarily. Then, the positive pressure reaches the vent pipe, pushes up the exhaust valve closing the inner vent, and opens the inner vent. As a result, the abnormally high positive pressure in the drainage pipe is discharged to the outside through the ventilation pipe. Then, when the pressure in the drain pipe returns to the normal atmospheric pressure state, the exhaust valve lowers due to its own weight or the like to close the inner vent hole again.
As a result, inspection / due to abnormal increase in pressure in the drainage pipe
It is possible to prevent the lid of the cleaning tube from rising and blowing off.

Immediately after the sewage flows down, the pressure of the air on the rear side of the sewage temporarily decreases. Then, the negative pressure reaches the ventilation pipe, sucks up the intake valve closing the outside ventilation port, and opens the outside ventilation port. As a result, outside air is introduced into the drain pipe from the outer vent through the vent pipe and releases the abnormally high negative pressure in the drain pipe. Then, when the pressure in the drain pipe returns to the normal atmospheric pressure state, the intake valve lowers due to its own weight or the like and closes the outer vent hole again. This prevents the accumulated water in the drain trap from breaking due to an abnormal decrease in pressure in the drain pipe, and prevents the offensive odor from flowing out of the drain pipe.

When the pressure in the drain pipe is in a normal state, the exhaust valve and the intake valve are kept closed, and the malodor in the drain pipe is not leaked to the outside.

The ventilation device includes a ventilation pipe body, a ventilation cover,
It is composed of only a combination of ventilation valves (exhaust valve and intake valve), and the first ventilation passage and the second ventilation passage are separated and formed by a simple partition, and the construction is simple.

Each of the two semi-circular communication parts obtained by dividing the cross section of the ventilation pipe into two is used as an inner ventilation port (exhaust ventilation port), and each of the two semi-circular communication parts provided around the ventilation pipe. Is an outer vent (intake vent), the opening areas of the inner vent and the outer vent are large, and the vent capacity (exhaust capacity or intake capacity) can be increased.

An exhaust valve is provided at the inner vent of the first ventilation passage, and an intake valve is provided at the outer vent of the second ventilation passage so as to be used for both intake and exhaust, inside each of the first ventilation passage and the second ventilation passage. By installing an exhaust valve at the vent, it can be used exclusively for exhaust.
By providing an intake valve at each of the outer vents of the air passage and the second air passage, it is possible to dedicate air intake. That is, it is possible to separate specifications for both intake and exhaust, exclusive for exhaust, and exclusive for intake while maintaining the same basic configuration.

The present invention according to claim 5 has the following actions. Since the valve seat surface of the ventilation valve (exhaust valve and intake valve) is set to be inclined with respect to the horizontal plane, the condensed water around the valve seat is allowed to naturally flow down from the inner vent hole and the outer vent hole into the vent pipe.
It is possible to avoid the occurrence of freezing of condensed water around the valve seat and prevent valve malfunction.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic view showing a ventilation device for both intake and exhaust, FIG. 2 is an exhaust state view of FIG. 1, FIG. 3 is a schematic view showing a ventilation pipe body, FIG. 4 is a schematic view showing a ventilation cover, and FIG. Is a schematic diagram showing an exhaust valve, FIG. 6 is a schematic diagram showing an intake valve, FIG. 7 is a schematic diagram showing a valve pivoting structure to a ventilation pipe body, FIG. 8 is a schematic diagram showing an exhaust ventilation device, and FIG. It is a schematic diagram which shows the ventilation device for intake.

The ventilation device 10 is provided on a ventilation pipe 11 communicating with a drain pipe (not shown) (FIGS. 1, 2, 8, and 9).

The ventilation device 10 comprises a ventilation pipe body 12, a ventilation cover 13, an exhaust valve 14 and an intake valve 15.

As shown in FIG. 3, the ventilation pipe main body 12 includes an inner cylinder portion 12A and an inner cylinder portion 1 which are fitted and bonded to the outer periphery of the ventilation pipe 11.
An outer cylinder portion 12 integrally formed with 2A via a rib 12B.
C, it has a partition 12D that is formed to rise on the diameter. In addition, the ventilation pipe main body 12 has a locking projection 12E that is locked to the upper end surface of the ventilation pipe 11 and determines the fitting position of the ventilation pipe 11 and the ventilation pipe main body 12 at the inner peripheral portion of the inner cylindrical portion 12A. It is provided in. Further, the ventilation pipe main body 12 is provided with two semicircular inner ventilation holes 16, 16 divided into two parts by a partition 12D in the inner region of the inner tubular portion 12A, and is sandwiched between the inner tubular portion 12A and the outer tubular portion 12C. The area is provided with two semicircular outer vents 17, 17 divided in two by a partition 12D. Also, the ventilation pipe body 1
The valve 2 has valve shaft mounting holes 18 at two diametrical positions on both sides of the partition 12D.

As shown in FIG. 4, the ventilation cover 13 has a cylindrical shape with a bottom fitted and bonded around the outer cylindrical portion 12C of the ventilation pipe body 12.

As shown in FIG. 5, the exhaust valve 14 is a semicircular vent valve that can open and close the inner vent 16 described above. The exhaust valve 14 can be opened / closed by inserting the valve shaft 14A provided at two positions in the diametrical direction into the valve shaft mounting hole 18 of the ventilation pipe body 12 and engaging (pivoting) (FIG. 7) to open / close the inner ventilation port 16. And Exhaust valve 1
In the closed state, the outer peripheral portion 4 is in close contact with the valve seat surface 21 formed by the upper end surface of the inner cylindrical portion 12A. At this time, the valve seat surface 21 of the exhaust valve 14 is set to be inclined with respect to the horizontal plane.

As shown in FIG. 6, the intake valve 15 is a semi-circular ventilation valve that can open and close the outer ventilation port 17 described above. For the intake valve 15, the valve shaft 15A provided at two positions in the diametrical direction is inserted into the valve shaft mounting hole 18 of the intake pipe main body 12 to be engaged (pivotally attached) (FIG. 7), and the outer vent 17 can be opened and closed. And Intake valve 1
In the closed state, the outer peripheral portion 5 is in close contact with the valve seat surface 22 formed by the upper end surface of the outer cylindrical portion 12C. At this time, the valve seat surface 22 of the intake valve 15 is set to be inclined with respect to the horizontal plane.

The constituent materials of the ventilation pipe 11, the ventilation pipe main body 12, and the ventilation cover 13 are AE having good impact resistance and weather resistance.
S resin is preferable, and vinyl chloride and polyethylene can be used as well.

The constituent material of the exhaust valve 14 and the intake valve 15 is preferably an olefinic thermoplastic elastomer having good cold resistance and heat resistance.

That is, in the ventilation device 10, the ventilation cover 13 is provided around the outer tube portion 12C of the ventilation pipe body 12, and the ventilation cover 13 is provided by the partition 12D provided at the center of the ventilation pipe body 12.
The inner space is divided into a first air passage 23 and a second air passage 24,
(a) The semicircular communication portion communicating with the ventilation pipe 11 of the first ventilation passage 23 is used as the inner ventilation port 16, and the ventilation pipe 11 of the first ventilation passage 23 is provided.
The semi-circular annular communication part that is in communication with the external space around is the outer vent 17, and (b) the semi-circular communication part that communicates with the vent pipe 11 of the second vent passage 24 is the inner vent 16, and the second vent passage A semi-circular annular communication portion that communicates with the external space around the ventilation pipe 11 of 24 is defined as an outer ventilation hole 17. The ventilation device 10 allows the exhaust valve 14 that is a semicircular ventilation valve to be pivotally attached to each of the inner ventilation holes 16 of the first ventilation passage 23 and the second ventilation passage 24, and also has a semicircular annular ventilation valve. The intake valve 25, which is a valve, can be pivotally attached to each of the outer ventilation holes 17 of the first ventilation passage 23 and the second ventilation passage 24.

Here, the exhaust valve 14 is set so as to close when the internal pressure of the ventilation pipe 11 is in a normal pressure state and open when it exceeds a certain positive pressure, and an abnormally high positive pressure in the drain pipe is set. Can be released to the outside. Further, the intake valve 15 is set to close when the internal pressure of the ventilation pipe 11 is in a normal pressure state and to open when the internal pressure of the ventilation pipe 11 exceeds a certain negative pressure, so that an abnormally high negative pressure in the drain pipe can be eliminated. To do.

Therefore, in the ventilation device 10, the selection of whether or not the exhaust valve 14 is installed for each inner ventilation hole 16 of the first ventilation passage 23 and the second ventilation passage 24, the first ventilation passage 23 and the second ventilation passage 23
By selecting whether or not to install the intake valve 15 for each outer vent 17 of the air passage 24, three types of valves as shown in (A) to (C) below can be selectively configured.

(A) Ventilation device 10 for both intake and exhaust (FIGS. 1 and 2) The exhaust valve 14 is provided in the inner ventilation port 16 of one of the first ventilation passage 23 and the second ventilation passage 24 (24). Is provided, and the other ventilation passage 2 of the first ventilation passage 23 and the second ventilation passage 24 is provided.
An intake valve 15 is provided at the outer vent 17 of No. 4 (23). According to this, in the ventilation device 10, the abnormal positive pressure in the drain pipe is released to the outside by the exhaust valve 14, and the abnormal negative pressure in the drain pipe can be eliminated by the intake valve 15.

(B) Exhaust ventilation device 10 (FIG. 8) An exhaust valve 14 is provided in each of the inner ventilation holes 16 of the first ventilation passage 23 and the second ventilation passage 24. According to this, the ventilation device 10 enables the abnormal positive pressure in the drain pipe to be released to the outside by the exhaust valve 14.

(C) Intake-only ventilation device 10 (FIG. 9) An intake valve 15 is provided in each of the outer ventilation holes 17 of the first ventilation passage 23 and the second ventilation passage 24. According to this, the ventilation device 10 can eliminate the abnormal negative pressure in the drain pipe by the intake valve 15.

The operation of this embodiment will be described below. Air intake / exhaust ventilation device 10 or exhaust air ventilation device 1
According to 0, when a large amount of sewage flows instantaneously in the drainage pipe, the pressure of the air on the front side of the sewage increases temporarily.
Then, the positive pressure reaches the ventilation pipe 11, and the inner ventilation port 16
The exhaust valve 14 which is closed is pushed up, and the inner vent 16 is opened. As a result, the abnormally high positive pressure in the drain pipe is discharged to the outside through the ventilation pipe 11. Then, when the pressure in the drain pipe returns to the normal atmospheric pressure state, the exhaust valve 14 lowers due to its own weight or the like and closes the inner vent 16 again. As a result, it is possible to prevent the lid of the inspection / cleaning pipe from being lifted or blown off due to an abnormal increase in the pressure in the drain pipe.

According to the intake / exhaust ventilation device 10 or the intake ventilation device 10, immediately after the sewage flows down, the pressure of the air on the rear side of the sewage temporarily decreases. Then, the negative pressure reaches the vent pipe 11, sucks up the intake valve 15 that closes the outer vent 17, and the outer vent 1
Open seven. As a result, outside air is introduced into the drainage pipe from the outer ventilation port 17 through the ventilation pipe 11 and releases an abnormally high negative pressure in the drainage pipe. Then, when the pressure in the drain pipe returns to the normal atmospheric pressure state, the intake valve 15 lowers due to its own weight or the like and closes the outer vent 17 again. This prevents the accumulated water in the drain trap from breaking due to an abnormal decrease in pressure in the drain pipe, and prevents the offensive odor from flowing out of the drain pipe.

When the pressure in the drainage pipe is in a normal state, the exhaust valve 14 and the intake valve 15 are kept closed, so that the bad odor in the drainage pipe is not leaked to the outside.

The ventilation device 10 comprises a combination of a ventilation pipe main body 12, a ventilation cover 13, and a ventilation valve (exhaust valve 14 and intake valve 15) only, and the first ventilation passage 23 and the second ventilation passage 2 are combined.
4 is separated and formed by a simple partition 12D, and the configuration is simple.

Each of the two semicircular communication portions obtained by dividing the ventilation pipe 11 into two sections is provided with an inner ventilation port 16 (exhaust ventilation port).
And each of the two semi-circular communication portions provided around the ventilation pipe is used as the outer ventilation port 17 (intake ventilation port), and the opening areas of the inner ventilation port 16 and the outer ventilation port 17 are Large, ventilation capacity (exhaust capacity or intake capacity)
Can be increased.

An exhaust valve 14 is provided at the inner vent 16 of the first vent passage 23, and an intake valve 15 is provided at the outer vent 17 of the second vent passage 24, so that both intake and exhaust can be performed. The exhaust valve 1 is attached to each inner vent 16 of the second vent passage 24.
It is possible to provide exhaust only by providing No. 4 and only intake by providing the intake valve 15 at each outer vent 17 of the first ventilation path 23 and the second ventilation path 24. That is, it is possible to separate specifications for both intake and exhaust, exclusive for exhaust, and exclusive for intake while maintaining the same basic configuration.

Since the valve seat surfaces 21 and 22 of the ventilation valves (exhaust valve 14 and intake valve 15) are set to be inclined with respect to the horizontal plane, the condensed water around the valve seat is discharged from the inner vent hole 16 and the outer vent hole 17 respectively. By allowing the water to flow down into the ventilation pipe 11 naturally, the occurrence of freezing of dew condensation water around the valve seat can be avoided, and defective valve operation can be prevented.

The embodiment of the present invention has been described in detail above with reference to the drawings. However, the specific configuration of the present invention is not limited to this embodiment, and changes in design within the scope not departing from the gist of the present invention can be made. Even if it exists, it is included in the present invention. For example, a semi-circular ventilation valve provided at each inner ventilation hole of the first ventilation passage and the second ventilation passage is an intake valve, and a semi-circular annular ventilation provided at each outer ventilation opening of the first ventilation passage and the second ventilation passage. The valve can be an exhaust valve.

Further, the exhaust valve and the intake valve are not limited to those set to the closed position by their own weight, but may be set to the closed position by the spring force.

Further, the exhaust valve and the intake valve are not limited to those which rotate and open and close, but may be those which move linearly in the vertical direction to open and close.

[0052]

As described above, according to the present invention, the pressure in the drainage pipe is kept at the same level as the atmospheric pressure, and the lid of the inspection / cleaning pipe is prevented from being lifted or blown off, or the accumulated water in the trap is broken. In the possible ventilation device, it is possible to obtain a ventilation device which has a simplified configuration, a large ventilation capacity, and the same basic configuration, and which can be classified into specifications for both intake and exhaust, exclusive for exhaust, and exclusive for intake.

Further, according to the present invention, it is possible to prevent the dew condensation water from freezing around the valve seat and prevent the malfunction of the valve.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an intake and exhaust ventilation device.

FIG. 2 is an exhaust state diagram of FIG.

FIG. 3 is a schematic view showing a ventilation pipe main body.

FIG. 4 is a schematic view showing a ventilation cover.

FIG. 5 is a schematic diagram showing an exhaust valve.

FIG. 6 is a schematic diagram showing an intake valve.

FIG. 7 is a schematic view showing a valve pivot attachment structure to a ventilation pipe body.

FIG. 8 is a schematic diagram showing an exhaust ventilation device.

FIG. 9 is a schematic diagram showing an intake ventilation device.

[Explanation of symbols]

 10 Ventilation device 11 Ventilation pipe 12 Ventilation pipe main body 12D Partition 13 Ventilation cover 14 Exhaust valve 15 Intake valve 16 Inner ventilation port 17 Outer ventilation ports 21, 22 Valve seat surface 23 First ventilation passage 24 Second ventilation passage

Claims (5)

[Claims] 1. A ventilation device comprising a ventilation valve provided in a ventilation pipe, wherein a ventilation cover is provided around an opening of a ventilation pipe main body, and a partition provided at a central portion of the opening defines a space inside the ventilation cover as a first ventilation path. The second ventilation passage is divided into two parts, and the ventilation pipe communication portion of the first ventilation passage is made into a semicircular inner ventilation port,
The external space communicating portion around the ventilation pipe of the first ventilation passage is a semi-circular outer ventilation hole, the ventilation pipe communicating portion of the second ventilation passage is a semi-circular inner ventilation hole, and the outside of the ventilation pipe periphery of the second ventilation passage is The space communication portion is a semi-circular outer vent, and the semi-circular vent valve can be attached to each of the inner vents of the first vent passage and the second vent passage. A ventilation device, wherein the ventilation device is attachable to each of the outer ventilation holes of the ventilation passage and the second ventilation passage. 2. An exhaust valve, which is the semi-circular vent valve, is provided at an inner vent of one of the first vent passage and the second vent passage, and the exhaust valve has a vent pipe internal pressure normally. Is set so as to close when a predetermined positive pressure is exceeded and to open when a certain positive pressure is exceeded, and the semi-circular annular ventilation is provided in the outer ventilation opening of the other ventilation path of the first ventilation path and the second ventilation path. 2. A ventilation device according to claim 1, further comprising an intake valve which is a valve, the intake valve being set to be closed when the internal pressure of the ventilation pipe is in a normal pressure state and to be opened when a certain negative pressure is exceeded. . 3. An exhaust valve, which is the semi-circular vent valve, is provided at each of the inner vents of the first vent passage and the second vent passage, and the exhaust valve keeps the vent pipe internal pressure in a normal pressure state. The ventilation device according to claim 1, wherein the ventilation device is set to close at a certain time and open when a certain positive pressure is exceeded. 4. An intake valve, which is the semi-annular ventilation valve, is provided in each of the outer ventilation ports of the first ventilation passage and the second ventilation passage, and the intake valve is provided with a ventilation pipe internal pressure in a normal pressure state. The ventilation device according to claim 1, which is set to close at a certain time and open when a certain negative pressure is exceeded. 5. The ventilation device according to claim 1, wherein the valve seat surface of the ventilation valve is inclined relative to a horizontal plane.