JP7701281B2 - Backflow prevention mass - Google Patents

Description

This disclosure relates to a backflow prevention block that is installed in a drainage pipe that connects indoor drainage equipment such as a toilet to a sewer pipe, and prevents wastewater that flows backward through the drainage pipe from entering the upstream side.

Generally, wastewater discharged from indoor drainage facilities such as toilets is discharged into the sewer main (hereinafter simply called the sewer pipe) via drainage pipes buried underground. In addition, a drainage basin is installed upstream of the connection point of the drainage pipe to the sewer pipe in order to remove and inspect waste such as garbage in the drainage pipe.

When a large amount of rainwater flows into a sewer pipe in a short period of time due to a typhoon or other event, the drainage capacity of the sewer pipe may be exceeded and the overflowing wastewater may back up the drainage pipe. Patent documents 1 to 3 disclose backflow prevention manholes with backflow prevention valves attached to the inlet opening inside the manhole to prevent wastewater that backs up from the sewer pipe from passing through the manhole and spewing out of the indoor drainage system.

JP 2008-261222 A JP 2010-126888 A JP 2018-204197 A

In a backflow prevention mass, the backflow prevention valve may wear over many years of use, reducing its ability to prevent backflow of wastewater, or the operating mechanism of the backflow prevention valve may be impaired, causing normal drainage. In contrast, the conventional backflow prevention masses disclosed in Patent Documents 1 to 3 allow the backflow prevention valve to be replaced.

However, in the backflow prevention mass of Patent Document 1, replacement of the backflow prevention valve requires attaching and detaching a nut deep inside the mass body, making it difficult to easily replace the backflow prevention valve. In addition, the method of fixing the backflow prevention valve in Patent Document 1 requires fitting a ring-shaped member onto a vertically extending shaft, making accurate positioning difficult and raising the risk of a gap occurring between the valve seat and the valve body. In addition, the backflow prevention masses of Patent Documents 2 and 3 are provided with a special valve body retaining member to enable replacement of the backflow prevention valve, which increases the manufacturing costs of the backflow prevention mass.

In view of the above, the present disclosure aims to make it possible to easily and inexpensively replace the valve body in a backflow prevention mass.

In order to achieve the above object, the first aspect of the present disclosure is a backflow prevention basin that is provided in a drainage pipe that connects an indoor drainage system to a sewer pipe and prevents wastewater that flows backward through the drainage pipe from entering the upstream side. The backflow prevention basin includes a drainage basin body, an inspection opening that opens at the top of the drainage basin body, inlet and outlet pipes for wastewater provided on the side wall of the drainage basin body, and a valve body configured to be able to close the downstream opening of the inlet pipe. At least the downstream end of the inlet pipe protrudes into the inside of the drainage basin body. A shaft support is provided on the downstream end of the inlet pipe, and the valve body is rotatably held on the shaft support. The valve body has a valve body, a rotating shaft provided on the valve body, and a shaft supported part provided at the end of the rotating shaft part and detachably held on the shaft support part. By removing the shaft supported part from the shaft support part, the valve body can be replaced through the inspection opening part.

According to the first aspect, a support part that rotatably holds the valve body is provided on the downstream end of the inlet pipe part that protrudes into the drainage manhole body. In addition, a supported part that is detachably held on the support part is provided on the end of the pivot part of the valve body. Therefore, the valve body can be easily replaced through the inspection hatch by simply removing the supported part from the support part. In addition, because the valve body can be replaced simply by configuring the supported part to be detachable from the support part, an increase in manufacturing costs can be suppressed.

In a second aspect of the present disclosure, in the first aspect, the rotating shaft portion has a substantially cylindrical shaft member and a shaft insertion portion into which the shaft member is inserted. The supported portion is provided at the end of the shaft member. The shaft insertion portion is formed integrally with the valve body and is rotatable with the shaft member as a support.

According to the second aspect, the supported part does not rotate in principle together with the shaft member, so the frictional force generated between the supported part and the support part can be reduced, suppressing wear on the support part, which is difficult to replace. Also, compared to a configuration in which the supported part rotates directly at the support part, the diameter of the shaft member, which is the shaft that supports the rotation of the valve body, can be made smaller, so the contact area of the shaft is reduced. As a result, the frictional force between the shaft member and the shaft insertion part can be reduced, making it easier for the valve body to rotate.

The third aspect of the present disclosure is the second aspect, in which the supported portion is a cap-shaped member having a hole into which the end of the shaft member is fitted.

According to the third aspect, the supported part can be attached to the shaft member more easily than when the supported part is a donut-shaped member with a through hole, improving the assembly accuracy of the backflow prevention mass.

The fourth aspect of the present disclosure is the second or third aspect, in which the supported portion and the shaft insertion portion are spaced apart.

According to the fourth aspect, compared to when the supported portion and the shaft insertion portion abut, it is possible to reduce friction when the shaft insertion portion rotates, and it is possible to prevent the supported portion from rotating (co-rotating) with the shaft insertion portion, thereby preventing increased wear between the supported portion and the shaft insertion portion.

A fifth aspect of the present disclosure is any one of the first to fourth aspects, in which the support portion is provided with a recess into which the supported portion is inserted. The recess has a tapered shape that widens as it approaches the upper end, and the portion of the bottom of the recess that abuts against the supported portion has an arc shape.

According to the fifth aspect, the opening side of the recess provided in the support part is widened, making it easier to assemble and remove the support part. In addition, even if the position of the support part shifts from the bottom of the recess (contact part) due to pressure on the valve body when suppressing backflow of drainage, the support part will tend to naturally return to its original contact part.

A sixth aspect of the present disclosure is any one of the first to fifth aspects, in which the valve body has a gripping portion for gripping the valve body during replacement.

According to the sixth aspect, when replacing the valve body, it is even easier to remove and attach the supported part to the support part.

A seventh aspect of the present disclosure is any one of the first to sixth aspects, in which the valve body closes the downstream opening of the inlet pipe section vertically when no drainage is occurring.

According to the seventh aspect, the valve body can be opened and closed easily when draining water. In addition, the valve body is less likely to come off when backflow of drainage water occurs, compared to when the valve body is tilted when no drainage is occurring.

The eighth aspect of the present disclosure is any one of the first to seventh aspects, in which the hardness of the material constituting the supported portion is lower than the hardness of the material constituting the support portion.

According to the eighth aspect, since the supported part is made of a softer material than the support part, the supported part can be easily removed from the support part, facilitating replacement of the valve body. In addition, wear on the support part, which is difficult to replace, can be suppressed when the supported part is attached to the support part, when the valve body is in operation, when the valve body is being replaced, etc.

A ninth aspect of the present disclosure is any one of the first to eighth aspects, in which the inlet pipe section has a valve pipe attached to the downstream side from the inside of the drainage basin body. The pivot support section is provided on the downstream end of the valve pipe. The valve body is configured to be able to close the downstream opening of the valve pipe.

According to the ninth aspect, the valve pipe that is opened and closed by the valve body is attached from the inside of the drainage manhole body, making it possible to attach the valve body integrally with the valve pipe, facilitating assembly of the backflow prevention manhole.

According to this disclosure, the valve body in the backflow prevention mass can be replaced easily and at low cost.

FIG. 1 is a diagram showing an example of a drainage pipeline in which a backflow prevention block according to an embodiment is provided. FIG. 2 is a vertical cross-sectional view of the backflow prevention mass according to the embodiment. 3 is a perspective view showing a valve body and a pivot support portion of the backflow prevention mass shown in FIG. 2. FIG. 4 is a perspective view showing the valve body of the backflow prevention mass shown in FIG. 2 detached from the pivot support portion and disassembled. FIG. 5 is a plan view showing the valve body and the journal portion of the check valve shown in FIG. 2. FIG. FIG. 6 is a cross-sectional view showing a state in which a supported portion is attached to an end of a shaft member of a pivot shaft portion in the valve body of the backflow prevention mass shown in FIG. 2. FIG. 7 is a perspective view showing a part of the valve body and the pivot support of the backflow prevention mass according to the first modification. FIG. 8 is a vertical cross-sectional view of a backflow prevention mass according to the second modification.

(Embodiment)
Hereinafter, a backflow prevention mass according to an embodiment of the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the embodiment shown below, and various modifications are possible within the scope of the technical concept of the present disclosure.

<Drainage pipe>
The backflow prevention basin 10 of this embodiment is provided in a drainage pipeline 1 that connects an indoor drainage facility 2 such as a toilet to a sewer pipe (not shown), as shown in FIG. 1. The backflow prevention basin 10 prevents wastewater flowing backward through the drainage pipeline 1 from entering the upstream side. For example, other drainage basins 3A, 3B, and 3C may be provided between the indoor drainage facility 2 and the backflow prevention basin 10 in the drainage pipeline 1 to remove filth such as garbage in the drainage pipeline 1 and to inspect the drainage pipeline 1. The piping that constitutes the drainage pipeline 1 may be, for example, a polyvinyl chloride pipe. The drainage pipeline 1 may be provided with a gentle downward slope toward the downstream.

<Backflow prevention block>
2, the backflow prevention tank 10 includes a drainage tank body 11, an inspection hatch 11a opening at the top of the drainage tank body 11, an inlet pipe 12 and an outlet pipe 13 for drainage provided on the side wall of the drainage tank body 11, and a valve body 14 configured to be able to close a downstream opening 12b of the inlet pipe 12. The backflow prevention tank 10 may be made of a synthetic resin such as polyvinyl chloride.

The inspection hatch 11a has a circular shape with a diameter of, for example, about 50 to 300 mm. By inserting a height adjustment adjuster or a lid (not shown) into the inspection hatch 11a, the backflow prevention tank 10 can be exposed to the ground surface, allowing inspection and maintenance of the backflow prevention tank 10.

The inlet pipe section 12 includes a first horizontal pipe section 121 arranged on the upstream side, an inclined pipe section 122 arranged downstream of the horizontal pipe section 121, a second horizontal pipe section 123 arranged downstream of the inclined pipe section 122, and a valve pipe 124 arranged downstream of the second horizontal pipe section 123. The first horizontal pipe section 121, the inclined pipe section 122, and the second horizontal pipe section 123 may be integrally molded. The valve pipe 124 is attached from the inside of the drainage basin body 11 and is connected horizontally to the second horizontal pipe section 123. A valve seat surface 12c that can abut against the valve body 14 is provided on the downstream end face of the valve pipe 124.

The bottom of each of the first horizontal pipe section 121 and the second horizontal pipe section 123 (the bottom of the pipe inner wall) is horizontal or approximately horizontal. The bottom of the inclined pipe section 122 is inclined downward toward the downstream side. Therefore, the bottoms of the inclined pipe section 122 and the second horizontal pipe section 123 are located lower than the bottom of the first horizontal pipe section 121. In other words, the downstream bottom of the inflow pipe section 12 is located lower than the upstream bottom of the inflow pipe section 12.

Although not shown, the upstream opening 12a of the inlet pipe section 12 (first horizontal pipe section 121) is connected to a pipe (upstream pipe on the indoor drainage equipment 2 side) that constitutes the drainage pipe line 1. Specifically, the outer diameter of the upstream pipe is approximately equal to the inner diameter of the first horizontal pipe section 121, and the downstream end of the upstream pipe is inserted into the first horizontal pipe section 121. A step 121a is provided along the inner circumference of the pipe at the boundary between the first horizontal pipe section 121 and the inclined pipe section 122. The inner surface of the inclined pipe section 122 may have a curved surface that bulges outward when viewed from the pipe axis of the inclined pipe section 122. This curved surface can smooth the flow of drainage. The inner diameters of the inclined pipe section 122 and the second horizontal pipe section 123 may be approximately equal to the inner diameter of the upstream pipe inserted into the first horizontal pipe section 121. The tip of the upstream pipe inserted into the first horizontal pipe section 121 abuts against the step 121a, thereby positioning the upstream pipe in the insertion direction.

The outer diameter of the second horizontal pipe section 123 is approximately equal to the diameter of the opening 11b of the drainage basin body 11. The downstream end of the second horizontal pipe section 123 may be connected to the upstream end of the valve pipe 124, for example, at the position of the opening 11b. A cylindrical section 11c that protrudes outward from the drainage basin body 11 so as to surround the opening 11b may be provided on the side wall around the opening 11b of the drainage basin body 11, and the second horizontal pipe section 123 may be inserted into the cylindrical section 11c. In this case, a protrusion 123a may be provided along the outer periphery of the pipe at the boundary between the second horizontal pipe section 123 and the inclined pipe section 122, and when the second horizontal pipe section 123 is inserted into the cylindrical section 11c, the protrusion 123a may abut against the tip of the cylindrical section 11c, thereby positioning the second horizontal pipe section 123. Furthermore, if the tip surface of the cylindrical portion 11c is made flush with a flat surface, the tip surface of the cylindrical portion 11c and the protrusion portion 123a can be in surface contact, so that the inlet pipe portion 12 (second horizontal pipe portion 123) and the drainage basin body 11 can be satisfactorily connected without using a gasket or the like.

The valve pipe 124, i.e., at least the downstream end of the inlet pipe section 12, protrudes into the drainage manhole body 11. The outer diameter of the valve pipe 124 is approximately equal to the diameter of the opening 11b of the drainage manhole body 11. An extension section 111 extending into the inside of the drainage manhole body 11 may be provided on the inner wall around the opening 11b of the drainage manhole body 11, and the valve pipe 124 may be supported by the extension section 111. The valve pipe 124 may be bonded to the cylindrical extension section 111 while inserted into the extension section 111.

The outflow pipe section 13 may be integrally formed with the drainage basin body 11. The bottom of the drainage basin body 11 and the bottom of the outflow pipe section 13 may be located at approximately the same height. Although not shown, the opening (downstream opening) of the outflow pipe section 13 is connected to a pipe (downstream pipe on the sewer pipe side) that constitutes the drainage pipeline 1. Specifically, the outer diameter of the downstream pipe is approximately equal to the inner diameter of the opening side of the outflow pipe section 13, and the upstream end of the downstream pipe is inserted into the outflow pipe section 13. Inside the outflow pipe section 13, a step 13a is provided along the inner circumference of the pipe, and the inner diameter of the outflow pipe section 13 upstream of the step 13a is smaller than the inner diameter of the opening side of the outflow pipe section 13, i.e., the outer diameter of the downstream pipe. As a result, the tip of the downstream pipe inserted into the outflow pipe section 13 abuts against the step 13a, thereby positioning the insertion direction of the downstream pipe.

In this embodiment, in order to facilitate the flow of wastewater and other materials that have passed through the downstream opening 12b of the inlet pipe section 12 (valve pipe 124) downstream, the bottom of the drainage manhole body 11 may be positioned further below the bottom of the valve pipe 124, i.e., the downstream bottom of the inlet pipe section 12. In this case, the drainage manhole body 11 may be provided with an inclined section that slopes downward downstream from the lower end of the downstream opening 12b of the valve pipe 124 to the bottom of the drainage manhole body 11. In addition, the drainage manhole body 11 may be provided with a horizontal section that connects to the inclined section and supports the valve pipe 124, and a support section that supports the horizontal section and is positioned below the opening 11b of the drainage manhole body 11.

The bottom of the drainage manhole body 11 may be provided with an invert section 11d having a semicircular cross section, for example. The bottom of the invert section 11d and the bottom of the outflow pipe section 13 may be located at approximately the same height. The invert section 11d may be provided by extending from the bottom of the drainage manhole body 11 to the downstream opening 12b of the valve pipe 124. In this way, the invert 11d connects the inflow pipe section 12 and the outflow pipe section 13, preventing sewage and the like from accumulating during drainage.

The inclination of the inclined pipe section 122 may be set so that the difference in height between the bottom of the first horizontal pipe section 121 and the bottom of the second horizontal pipe section 123 (i.e., the bottom of the valve pipe 124) is about 1/4 or more of the inner diameter of the upstream pipe (the pipe connected to the inlet pipe section 12 from the upstream side). Alternatively, the inclination of the inclined pipe section 122 may be set so that the extension line of the pipe axis (center axis) of the first horizontal pipe section 121 passes through the downstream opening 12b of the valve pipe 124 without intersecting the inner wall surface of the inclined pipe section 122. In other words, the difference in height between the bottom of the first horizontal pipe section 121 and the bottom of the valve pipe 124 (second horizontal pipe section 123) may be set to less than 50% of the inner diameter of the inclined pipe section 122 (the inner diameter of the upstream pipe).

<Valve body and pivot support>
2 to 5, a journal portion 15 is provided on the downstream end of the valve pipe 124, i.e., the inlet pipe section 12, and the valve body 14 is rotatably held by the journal portion 15. The journal portion 15 may be formed integrally with the valve pipe 124 at the top of the valve pipe 124.

The valve body 14 mainly has a valve body 141 and a rotating shaft portion 143. The valve body 141 is configured in a substantially disk shape so as to be capable of closing the downstream opening 12b of the inlet pipe portion 12. A connection portion 141a that connects to the rotating shaft portion 143 is provided at the top of the valve body 141. A shaft support portion 144 that is detachably held by the shaft support portion 15 is provided at both ends of the rotating shaft portion 143.

In this embodiment, the center of gravity of the valve body 141 is located downstream of the pivot shaft 143, and the connection part 141a has a shape that is bent from the valve body 141 toward the upstream side toward the pivot shaft 143. The connection part 141a serves as a gripped part for gripping the valve body 14 when replacing the valve body 14. The connection part 141a and the gripped part may be provided separately.

The opening surface of the downstream opening 12b of the inflow pipe section 12 (valve pipe 124) is substantially a vertical surface, and the valve body 141 blocks the downstream opening 12b substantially vertically along this vertical surface when no drainage is occurring. That is, the angle that the disk shape of the valve body 141 makes with the vertical surface when blocking the downstream opening 12b is substantially 0°. A valve seat surface 12c that can abut against the valve body 141 is provided on the downstream end surface of the inflow pipe section 12, that is, the peripheral portion of the downstream opening 12b in the valve pipe 124. The valve seat surface 12c is configured to be able to abut against the valve body 141 when drainage backflows. The valve seat surface 12c may be provided in a downstream direction from the inner peripheral surface to the end surface of the inflow pipe section 12 (valve pipe 124). That is, the valve seat surface 12c may be a tapered surface (inclined surface). An annular packing 16 that can be fitted tightly to the valve seat surface 12c of the inlet pipe section 12 is provided on the outer circumferential surface of the valve body 141. The packing 16 may be, for example, a V-packing. In this way, the packing 16 is more tightly fitted to the valve seat surface 12c, and the water-stopping effect of the valve body 141 when wastewater backflows is increased.

The rotating shaft portion 143 is composed of, for example, a substantially cylindrical shaft member 145 and a shaft insertion portion 146 having a through hole 146a into which the shaft member 145 is inserted. The shaft support portion 144 is provided at both ends of the shaft member 145. The shaft member 145 is made of, for example, stainless steel. The shaft insertion portion 146 is formed integrally with the valve body 141 (connection portion 141a). The diameter of the through hole 146a of the shaft insertion portion 146 is larger than the diameter of the shaft member 145. This allows the shaft insertion portion 146 to rotate together with the valve body 141, using the shaft member 145 as a support. The shaft insertion portion 146 and the shaft support portion 144 may be spaced apart.

The supported portion 144 may be, for example, a cylindrical cap member having a hole 144a into which the end of the shaft member 145 is fitted. Specifically, as shown in FIG. 6, the hole 144a of the supported portion 144 may have a tapered shape that narrows toward the back. This makes it easier to press the shaft member 145 into the hole 144a of the supported portion 144 when attaching the supported portion 144 to the shaft member 145, and makes it difficult for the supported portion 144 to come off the shaft member 145. In particular, by suddenly narrowing the hole 144a at the deepest part of the hole 144a, the shaft member 145 is engaged with the supported portion 144, which makes it easier to position and fix the two.

The support portion 15 is provided with a recess 15a into which the supported portion 144 is inserted. The recess 15a has, for example, a tapered shape that widens as it approaches the upper end, and the portion of the bottom of the recess 15a that abuts against the supported portion 144 has an arc shape that corresponds to the shape of the supported portion 144. The support portion 15 may have a base 15b that connects to the valve pipe 124, as shown in FIG. 5. Also, a protrusion 124a used to align the drainage manhole body 11 and the valve body 124 may be provided integrally with the base 15b at the top of the valve pipe 124.

In this embodiment, the supported portion 144 is left in the recess 15a of the support portion 15 without any other fixing means. This improves the workability when installing the valve body 14 or replacing the valve body 14. On the other hand, even if the weight of the valve body 14 itself (for example, about 100 g) causes the supported portion 144 to shift in position within the recess 15a of the support portion 15, the supported portion 144 naturally returns to its original position (the bottom of the recess 15a). In addition, when there is no drainage, the valve body 141 is fitted into the valve pipe 124 side due to the effect of the packing (V packing), so the supported portion 144 is less likely to shift in position within the recess 15a. Furthermore, when backflow is prevented, the valve body 141 is tightly attached to the valve seat surface 12c of the inlet pipe portion 12 (valve pipe 124), so that the supported portion 144 is even less likely to shift in position within the recess 15a.

In addition, in this embodiment, the bottom of the recess 15a has a curvature that fits the cap-shaped supported portion 144, so the support portion 15 and the supported portion 144 are in surface contact. In contrast, in the rotating shaft portion 143 of the valve body 14, the shaft member 145 on which the supported portion 144 is provided and the through hole 146a of the shaft insertion portion 146 have different diameters, so they are basically in line contact. Therefore, the frictional force between the support portion 15 and the supported portion 144 is greater than the frictional force between the shaft member 145 and the shaft insertion portion 146, so the shaft insertion portion 146 can rotate together with the valve body 141, using the shaft member 145 as a support.

In addition, if the shaft member 145 and the shaft insertion portion 146 (through hole 146a) become stuck due to, for example, aging, in other words, if the shaft insertion portion 146 (valve body 141) can no longer rotate with the shaft member 145 as support, the cylindrical shaft support portion 144 can rotate within the recess 15a because the bottom of the recess 15a is arc-shaped.

In the above description, a cylindrical cap member is used as the supported portion 144, and the contact portion of the recess 15a with the supported portion 144 is arc-shaped. Alternatively, the supported portion 144 may be configured with a cornered shape (e.g., a rectangular parallelepiped shape), and the recess 15 may be shaped to match the supported portion 144. In this case, if the shaft member 145 and the shaft insertion portion 146 are fixed, the supported portion 144 cannot be rotated within the recess 15a, but since the supported portion 144 is less likely to move within the recess 15a, wear on the support portion 15, which is difficult to replace, can be reduced.

In this embodiment, the hardness of the material of the supported portion 144 is preferably lower than the hardness of the material of the support portion 15. For example, the supported portion 144 may be made of polyethylene resin or a polyethylene-based elastomer, and the support portion 15 may be made of a hard polyvinyl chloride resin. In this way, when the supported portion is made of a material that is softer than the support portion 15, the supported portion 144 becomes easier to remove from the support portion 15, making it easier to replace the valve body 14. In addition, wear of the support portion 15, which is difficult to replace, can be suppressed when the supported portion 144 is assembled to the support portion 15, when the valve body 14 is in operation, when the valve body 14 is replaced, etc. Furthermore, even if the shaft member 145 and shaft insertion portion 146 become stuck and the supported portion 144 rotates within the recess 15a of the support portion 15, the self-lubricating properties of plastic are exerted, suppressing wear on the support portion 15 and limiting wear on the supported portion 144, ensuring the service life of the valve body 14 (for example, 10 years).

<Operation of backflow prevention mass>
When no drainage is required, the valve body 141 contacts the valve seat surface 12c of the inflow pipe section 12 to block the downstream opening 12b of the inflow pipe section 12. When the valve body 141 is blocking the downstream opening 12b, if wastewater flows out of the indoor drainage system 2, the wastewater that flows into the inflow pipe section 12 through the drainage pipe line 1 pushes open the valve body 141 that is in contact with the valve seat surface 12c of the inflow pipe section 12 by water pressure. As a result, the wastewater flows from the inflow pipe section 12 into the drainage basin body 11, and the wastewater flows out of the backflow prevention basin 10 through the outflow pipe section 13. In addition, since the center of gravity of the valve body 141 is located downstream of the pivot shaft section 143, when the wastewater flows out of the inflow pipe section 12, the valve body 141 closes the downstream opening 12b again by its own weight.

On the other hand, even if the drainage capacity of the sewer pipe is exceeded due to heavy rain or the like and the overflowing drainage water flows back up the drainage pipe 1, the downstream opening 12b of the inlet pipe section 12 is blocked by the valve body 141, so the drainage water will not enter the drainage pipe 1 upstream of the valve body 14. Therefore, the backflowing drainage water and the air compressed by this drainage water can be prevented from spraying out of the indoor drainage equipment 2.

<Replacing the valve body>
In this embodiment, the valve body 14 can be replaced through the inspection port 11a by removing the supported portion 144 of the valve body 14 from the support portion 15 (recess 15a). At this time, the center of gravity of the valve body 141 is located downstream of the rotating shaft portion 143 on which the supported portion 144 is provided. In other words, the connecting portion 141a connecting the valve body 141 and the rotating shaft portion 143 has a shape that is bent from the valve body 141 toward the rotating shaft portion 143 on the upstream side. Therefore, the valve body 14 can be easily replaced (removal of the old valve body 14 and installation of the new valve body 14) while avoiding interference between the packing 16 of the valve body 14 and the valve pipe 124. Also, as described above, by making the supported part 144 out of a softer material than the support part 15, the supported part 144 can be easily removed from the support part 15, making replacement of the valve body 14 even easier and suppressing wear of the support part 15, which is difficult to replace. Furthermore, if the backflow prevention mass 10 is buried deep underground and a jig (e.g., a magic wand) needs to be used to replace the valve body 14, the connection part 141a (gripped part) is gripped with the jig for replacement, and in this case, even if the valve body 14 and the support part 15 come into contact with each other at a position other than the predetermined position, the support part 15 is less likely to be damaged.

<Features of the embodiment>
As described above, according to the backflow prevention basin 10 of this embodiment, the axial support portion 15 that rotatably holds the valve body 14 is provided on the valve pipe 124 (the downstream end of the inlet pipe portion 12) that protrudes into the drainage basin body 11. In addition, the axially supported portion 144 that is detachably held on the axial support portion 15 is provided on the end of the pivot shaft portion 143 of the valve body 14. Therefore, the valve body 14 can be easily replaced through the inspection opening portion 11a simply by removing the axially supported portion 144 from the axial support portion 15. In addition, since the valve body 14 can be replaced simply by configuring the axially supported portion 144 to be detachable from the axial support portion 15, an increase in manufacturing costs can be suppressed.

In the backflow prevention mass 10 of this embodiment, the rotating shaft portion 143 of the valve body 14 may have a substantially cylindrical shaft member 145 and a shaft insertion portion 146 into which the shaft member 145 is inserted. The supported shaft portion 144 is provided at the end of the shaft member 145, and the shaft insertion portion 146 may be formed integrally with the valve body 141 and be rotatable with the shaft member 145 as a support. In this way, the supported shaft portion 144 does not rotate in principle together with the shaft member 145, and the frictional force generated between the supported shaft portion 144 and the support portion 15 can be reduced, so that wear of the support portion 15, which is difficult to replace, can be suppressed. In addition, compared to a configuration in which the supported shaft portion 144 rotates directly at the support portion 15, the diameter of the shaft member 145, which is the shaft that supports the rotation of the valve body 141, can be made smaller, so that the contact area of the shaft is reduced. This reduces the friction between the shaft member 145 and the shaft insertion portion 146, making it easier for the valve body 141 to rotate.

In the backflow prevention mass 10 of this embodiment, the supported portion 144 may be a cap-shaped member having a hole 144a into which the end of the shaft member 145 is fitted. In this way, it is easier to attach the supported portion 144 to the shaft member 145 compared to when the supported portion 144 is a donut-shaped member having a through hole, improving the assembly accuracy of the backflow prevention mass 10.

In the backflow prevention mass 10 of this embodiment, the supported portion 144 and the shaft insertion portion 146 may be spaced apart. In this way, compared to when the supported portion 144 and the shaft insertion portion 146 abut, it is possible to reduce friction when the shaft insertion portion 146 rotates, and it is possible to prevent the supported portion 144 from rotating (rotating together) with the shaft insertion portion 146, thereby preventing increased wear between the supported portion 144 and the shaft insertion portion 146.

In the backflow prevention mass 10 of this embodiment, the support portion 15 may be provided with a recess 15a into which the supported portion 144 is inserted. The recess 15a may have a tapered shape that widens as it approaches the upper end, and the portion of the recess 15a that abuts against the supported portion 144 at the bottom may have an arc shape. In this way, the opening side of the recess 15a provided in the support portion 15 is widened, making it easier to assemble and remove the supported portion 144. In addition, even if the position of the supported portion 144 shifts from the bottom of the recess 15a (the abutment portion) due to pressure on the valve body 14 when suppressing the backflow of wastewater, the supported portion 144 will tend to naturally return to its original abutment portion.

In the backflow prevention mass 10 of this embodiment, the valve body 14 may have a gripped portion (connection portion 141a) for gripping the valve body 14 during replacement. In this way, it is even easier to remove and attach the supported portion 144 to the support portion 15 when replacing the valve body 14.

In addition, in the backflow prevention mass 10 of this embodiment, the valve body 141 may block the downstream opening 12b of the inlet pipe section 12 substantially vertically when no drainage is occurring. In this way, the valve body 141 can be easily opened and closed when drainage is occurring. Also, compared to when the valve body 141 is tilted when no drainage is occurring, the valve body 14 is less likely to come off when backflow of drainage occurs.

In addition, in the backflow prevention mass 10 of this embodiment, the hardness of the constituent material of the supported portion 144 may be lower than the hardness of the constituent material of the support portion 15. In this way, the supported portion 144 is made of a softer material than the support portion 15, making it easier to remove the supported portion 144 from the support portion 15 and facilitating replacement of the valve body 14. In addition, wear of the support portion 15, which is difficult to replace, can be suppressed when the supported portion 144 is assembled to the support portion 15, when the valve body 14 is in operation, when the valve body 14 is replaced, etc.

In addition, in the backflow prevention basin 10 of this embodiment, the inlet pipe section 12 may have a valve pipe 124 attached to the downstream side from the inside of the drainage basin body 11. A shaft support section 15 may be provided on the downstream end of the valve pipe 124, and the valve body 14 may be configured to be able to close the downstream opening 12b of the valve pipe 124. In this way, since the valve pipe 124 that is opened and closed by the valve body 14 is attached from the inside of the drainage basin body 11, it is possible to attach the valve body 14 integrally with the valve pipe 124, making it easier to assemble the backflow prevention basin 10.

In addition, the backflow prevention mass 10 of this embodiment may have the following features:

In the wastewater inlet pipe section 12 provided on the side wall of the drainage manhole body 11, the downstream pipe bottom may be located lower than the upstream pipe bottom. In this way, the flow rate of the wastewater increases when the wastewater flows from the upstream side to the downstream side of the inlet pipe section 12, so the valve body 141 of the valve body 14 that blocks the downstream opening 12b of the inlet pipe section 12 is more likely to open due to the flow of the wastewater. Therefore, even if the amount of wastewater is small, it is possible to prevent the backflow prevention manhole 10 from becoming clogged with sewage or the like. This configuration is particularly useful when the flow gradient of the pipe connected from the upstream side to the inlet pipe section 12 is small and the flow rate of the wastewater in the pipe is low.

The bottom of the drainage manhole body 11 may be located below the bottom of the downstream pipe of the inlet pipe section 12. This can prevent waste matter from accumulating downstream of the valve body 141 in the drainage manhole body 11 and impeding the opening of the valve body 141. This can further prevent drainage blockages caused by waste matter in the backflow prevention manhole 10.

The height difference between the downstream pipe bottom and the upstream pipe bottom in the inflow pipe section 12 may be approximately 1/4 or more of the inner diameter of the piping connected to the inflow pipe section 12 from the upstream side. In this way, the flow rate of the wastewater can be sufficiently increased when the wastewater flows from the upstream side to the downstream side of the inflow pipe section 12, making it easier for the valve body 141 to open due to the flow of the wastewater. Therefore, the backflow prevention mass 10 can be further prevented from becoming clogged with wastewater due to sewage, etc.

The inflow pipe section 12 may include a first horizontal pipe section 121 that is located upstream and has a horizontal or nearly horizontal pipe bottom, and an inclined pipe section 122 that is located downstream of the first horizontal pipe section 121 and has a pipe bottom that is inclined downward toward the downstream side. In this way, the piping that is connected to the inflow pipe section 12 from the upstream side can be easily connected to the first horizontal pipe section 121 of the inflow pipe section 12.

The inflow pipe section 12 may further include a second horizontal pipe section 123 that is located downstream of the inclined pipe section 122, is connected to the drainage manhole body 11, and has a horizontal or nearly horizontal pipe bottom. In this way, the second horizontal pipe section 123 of the inflow pipe section 12 can be easily attached to the side wall of the drainage manhole body 11.

The extension of the pipe axis of the first horizontal pipe section 121 may pass through the downstream opening 12b of the inlet pipe section 12 without intersecting with the inner wall surface of the inclined pipe section 122. In this way, it is possible to avoid a situation in which wastewater flows from the upstream side to the downstream side of the inlet pipe section 12 and collides with the pipe apex (the apex of the pipe inner wall) of the inclined pipe section 122, causing a decrease in the flow rate of the wastewater. This makes it possible to realize a state in which the valve body 141 is easily opened by the flow of wastewater.

The first horizontal pipe section 121, the inclined pipe section 122, and the second horizontal pipe section 123 may be molded as a single unit. In this way, the number of components of the backflow prevention mass 10 can be reduced, making it easier to assemble the backflow prevention mass 10.

(Variation 1)
The difference between the first modified example and the above embodiment is the structure of the pivot shaft portion 143 and the pivotally supported portion 144 of the valve body 14, as shown in Fig. 7. Note that Fig. 7 only shows one end side of the pivot shaft portion 143. In Fig. 7, the same components as those in the above embodiment shown in Figs. 2 to 5 are denoted by the same reference numerals.

In the first modification, the end 143a of the pivot shaft 143 is thinner than the other portions, and the end 143a is rotatably inserted into a through hole of the donut-shaped pivot support portion 144. That is, in the first modification, the pivot shaft 143 is configured to be rotatable together with the valve body 141, with the pivot support portion 144 as a support.

The supported shaft portion 144 is placed in a semi-fixed state in the recess 15a of the support portion 15. In other words, a clearance is provided between the supported shaft portion 144 and the recess 15a. The supported shaft portion 144 may receive the torque of the rotation of the rotating shaft portion 143 (end portion 143a) and rotate at a slower speed than the rotating shaft portion 143. The end portion 143a of the rotating shaft portion 143 may be provided with a stopper 147 to prevent the supported shaft portion 144 from falling off.

In variant 1, the same effect as in the above embodiment can be obtained. That is, the valve body 14 can be easily replaced through the inspection port 11a simply by removing the supported portion 144 from the support portion 15. In addition, since the valve body 14 can be replaced simply by configuring the supported portion 144 to be detachable from the support portion 15, an increase in manufacturing costs can be suppressed.

In addition, even in the first modified example, it is preferable that the hardness of the material of the supported portion 144 is lower than that of the material of the support portion 15. For example, the supported portion 144 may be made of polyethylene resin or polyethylene-based elastomer, and the support portion 15 may be made of hard polyvinyl chloride resin. In this way, when the supported portion is made of a material that is softer than the support portion 15, the supported portion 144 is easier to remove from the support portion 15, making it easier to replace the valve body 14. In addition, when the supported portion 144 is assembled to the support portion 15, when the valve body 14 is in operation, when the valve body 14 is replaced, etc., wear of the support portion 15, which is difficult to replace, can be suppressed. Furthermore, even if the supported portion 144 rotates within the recess 15a of the support portion 15, the self-lubricating property, which is a characteristic of plastic, is exhibited, so that wear of the support portion 15 is suppressed and wear of the supported portion 144 is also limited, and the service life of the valve body 14 (for example, 10 years) can be met.

(Variation 2)
The difference between the second modification and the above embodiment is that, as shown in Fig. 8, the inflow pipe section 12 is configured without using a valve pipe 124, in other words, the downstream side of the inflow pipe section 12 (the second horizontal pipe section 123) is inserted into the inside of the drainage basin body 11. In Fig. 8, the same components as those in the above embodiment shown in Fig. 2 are denoted by the same reference numerals.

In the second modification, the second horizontal pipe section 123 is inserted from the outside to the inside of the drainage manhole body 11 through the opening 11b of the side wall of the drainage manhole body 11, thereby connecting the drainage manhole body 11 and the inflow pipe section 12. The outer diameter of the second horizontal pipe section 123 is approximately equal to the diameter of the opening 11b of the drainage manhole body 11. The downstream opening 12b of the inflow pipe section 12 (second horizontal pipe section 123) is located closer to the inside of the drainage manhole body 11 than the opening 11b of the drainage manhole body 11. The end face of the second horizontal pipe section 123 is provided with a valve seat surface 12c that can abut against the valve body 141. When the second horizontal pipe section 123 is inserted into the opening 11b, the protrusion section 123a of the second horizontal pipe section 123 abuts against the side wall (cylindrical section 11c) around the opening 11b of the drainage manhole body 11, thereby positioning the insertion direction of the second horizontal pipe section 123.

An extension portion 111 may be provided above the opening 11b in the inner wall of the drainage manhole body 11, extending toward the inside of the drainage manhole body 11 along the outer periphery of the second horizontal pipe portion 123. The pivot support portion 15 may be fixed to the extension portion 111 by a method such as gluing, screwing, or welding. The rotating shaft portion 143 pivotally supported by the pivot support portion 15 is positioned upstream of the center of gravity of the valve body 141. The extension portion 111 may be integrally molded with the drainage manhole body 11.

According to variant example 2, the downstream side of the inlet pipe section 12 is inserted into the inside of the drainage manhole body 11, simplifying the configuration of the inlet pipe section 12 and facilitating assembly of the backflow prevention manhole 11.

Other Embodiments
In the above embodiment (including the modified example, the same applies below), the backflow prevention mass 10 is provided in the drainage pipeline 1 configured in series. However, this is not limited to this, and the backflow prevention mass 10 may be provided in a drainage pipeline including multiple pipes configured in parallel using, for example, a drainage header or the like.

In addition, in the above embodiment, one inlet pipe section 12 and one outlet pipe section 13 for drainage are provided on the side wall of the drainage manhole body 11. However, this is not limited to this, and multiple inlet pipe sections 12 and multiple outlet pipe sections 13 may be provided on the side wall of the drainage manhole body 11.

In the above embodiment, the inflow pipe section 12 is composed of a first horizontal pipe section 121, an inclined pipe section 122, a second horizontal pipe section 123, and a valve pipe 124. However, the configuration of the inflow pipe section 12 is not particularly limited. For example, the first horizontal pipe section and/or the second horizontal pipe section 123 may not be provided. Alternatively, a third horizontal pipe section may be provided midway through the inclined pipe section 122.

In addition, in the above embodiment, the inlet pipe section 12 and the drainage manhole body 11 are separate bodies, but instead, the inlet pipe section 12 and the drainage manhole body 11, excluding the valve pipe 124, may be integrally molded.

In addition, in the above embodiment, the pivot support portion 15 and the valve pipe 124 are integrally molded, but instead, the pivot support portion 15 may be removably fixed to the valve pipe 124 by means of screws or the like. By making the pivot support portion 15 removable, it becomes possible to replace the pivot support portion 15 in the unlikely event that it is damaged.

Although the embodiments have been described above, it will be understood that various changes in form and details are possible without departing from the spirit and scope of the claims. Furthermore, the above embodiments may be combined or substituted as appropriate as long as the functionality of the subject matter of this disclosure is not impaired. Furthermore, the descriptions "first," "second," ... described above are used to distinguish the words to which these descriptions are attached, and do not limit the number or order of the words.

REFERENCE SIGNS LIST 1 drainage pipeline 2 indoor drainage equipment 3A, 3B, 3C drainage manhole 10 backflow prevention manhole 11 drainage manhole body 11a inspection port section 11b opening 11c cylindrical section 11d invert section 111 extension section 12 inlet pipe section 12a upstream opening 12b downstream opening 12c valve seat surface 121 first horizontal pipe section 121a step 122 inclined pipe section 123 second horizontal pipe section 123a protrusion section 124 valve pipe 124a convex section 13 outlet pipe section 13a step 14 valve body 141 valve body 141a connection section 143 pivot shaft section 144 shaft supported section 144a hole 145 shaft member 146 shaft insertion section 146a through hole 147 Stopper 15 Axle support 15a Recess 15b Base 16 Packing

Claims (9)

A backflow prevention block is provided in a drainage pipe that connects an indoor drainage system to a sewer pipe, and prevents wastewater flowing backward through the drainage pipe from entering the upstream side.
A drainage basin body,
An inspection port opening at an upper portion of the drainage basin body;
A drainage inlet pipe portion and a drainage outlet pipe portion provided on a side wall of the drainage basin body;
a valve body configured to be able to close a downstream opening of the inlet pipe portion,
At least a downstream end of the inlet pipe portion protrudes into the inside of the drainage basin body,
a bearing portion is provided on the downstream end of the inlet pipe portion, and the valve body is rotatably held on the bearing portion,
The inflow pipe section includes a horizontal pipe section connected to the drainage basin body and having a horizontal or substantially horizontal pipe bottom, and an inclined pipe section disposed upstream of the horizontal pipe section and having a pipe bottom inclined downward toward the downstream side ,
The valve body is
A valve body;
A pivot shaft portion provided on the valve body;
a supported portion provided at an end of the pivot shaft portion and detachably held by the support portion;
The support portion is provided with a recess into which the supported portion is inserted,
By removing the supported part from the support part, the valve body can be replaced through the inspection port.
Backflow prevention mass. The rotation shaft portion is
A substantially cylindrical shaft member;
a shaft insertion portion into which the shaft member is inserted,
The supported portion is provided at an end of the shaft member,
The shaft insertion portion is formed integrally with the valve body and is rotatable with the shaft member as a support.
The backflow prevention mass according to claim 1 . The supported portion is a cap-shaped member having a hole into which the end of the shaft member is fitted.
The backflow prevention mass according to claim 2. The supported portion and the shaft insertion portion are spaced apart from each other.
A backflow prevention mass according to claim 2 or 3. The recess has a tapered shape that widens toward an upper end, and a portion of the bottom of the recess that abuts against the supported portion has an arc shape.
A backflow prevention mass according to any one of claims 1 to 4. The valve body has a gripping portion for gripping the valve body during replacement.
A backflow prevention mass according to any one of claims 1 to 5. The valve body vertically closes the downstream opening of the inlet pipe portion when no drainage is performed.
A backflow prevention mass according to any one of claims 1 to 6. The hardness of the constituent material of the supported portion is lower than the hardness of the constituent material of the supporting portion.
A backflow prevention mass according to any one of claims 1 to 7. The inlet pipe section has a valve pipe attached from the inside of the drainage basin body on the downstream side,
The support portion is provided on a downstream end of the valve pipe,
The valve body is configured to be capable of closing a downstream opening of the valve pipe.
A backflow prevention mass according to any one of claims 1 to 8.