Backflow prevention mass

Abstract

To easily replace a valve body of a backflow prevention basin at a low cost.SOLUTION: A backflow prevention basin 10 is installed in a drainage pipeline that connects an indoor drainage system to a sewer line. The backflow prevention basin 10 comprises a drain basin main body 11, an inspection port 11a open at the top of the drain basin main body 11, a drainage inflow pipe portion 12 and an outflow pipe portion 13 provided on the side wall of the drain basin main body 11, and a valve body 14 configured to be able to close a downstream opening 12b of the inflow pipe portion 12. A pivot portion 15 is provided on the downstream end of the inflow pipe portion 12. The valve body 14 is rotatably held by the pivot portion 15. The valve body 14 includes a valve main body 141, a rotating shaft portion 143 provided on the valve main body 141, and a pivoted portion 144 provided at the end of the rotating shaft portion 143. The pivoted portion 144 is detachably held by the pivot portion 15.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a backflow prevention mass provided in a drainage pipeline connecting indoor drainage facilities such as toilets to a sewer pipe, and preventing the intrusion of drainage flowing backward in the drainage pipeline into the upstream side.

Background Art

[0002] Generally, the drainage discharged from indoor drainage facilities such as toilets is discharged into the main sewer pipe (hereinafter simply referred to as the sewer pipe) via a drainage pipeline buried in the ground. In addition, in order to remove and inspect dirt such as garbage in the drainage pipeline, a drainage mass is installed on the upstream side of the connection point with the sewer pipe in the drainage pipeline.

[0003] When a large amount of rainwater flows into the sewer pipe in a short time due to a typhoon or the like, the drainage that overflows beyond the drainage capacity of the sewer pipe may flow backward in the drainage pipeline. Patent Documents 1 to 3 disclose a backflow prevention mass in which a backflow prevention valve is attached to the inflow side opening inside the drainage mass in order to prevent the drainage flowing backward from the sewer pipe from spraying out from the indoor drainage facilities through the drainage mass.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the backflow prevention mass, due to long-term use, the backflow prevention valve may wear out, reducing its ability to prevent backflow of drainage, or there may be a problem with the operating mechanism of the backflow prevention valve, which may prevent normal drainage. In contrast, in the conventional backflow prevention masses disclosed in Patent Documents 1 to 3, it is possible to replace the backflow prevention valve.

[0006] However, in the backflow prevention mass of Patent Document 1, in order to replace the backflow prevention valve, it is necessary to perform nut attachment / detachment work deep inside the mass body, and the backflow prevention valve cannot be easily replaced. Also, in the fixing method of the backflow prevention valve of Patent Document 1, since it is necessary to fit a ring-shaped member onto a shaft extending in the vertical direction, accurate positioning is difficult, and there is a possibility that a gap may occur between the valve seat and the valve body. Further, in the backflow prevention masses of Patent Documents 2 and 3, in order to enable replacement of the backflow prevention valve, a special valve body holding member is provided, increasing the manufacturing cost of the backflow prevention mass.

[0007] In view of the above, an object of the present disclosure is to enable easy and low-cost replacement of the valve body in the backflow prevention mass.

Means for Solving the Problem

[0008] To achieve the above object, a first aspect according to the present disclosure is a backflow prevention mass provided in a drainage pipe connecting indoor drainage facilities and a sewer pipe, and preventing intrusion of drainage flowing back in the drainage pipe into the upstream side. The backflow prevention mass includes a drainage mass body, an inspection port portion opening at the upper part of the drainage mass body, an inflow pipe portion and an outflow pipe portion for drainage provided on a side wall of the drainage mass body, and a valve body configured to be able to close a downstream opening of the inflow pipe portion. At least a downstream end of the inflow pipe portion protrudes into the drainage mass body. A shaft support portion is provided above the downstream end of the inflow pipe portion, and the valve body is rotatably held by the shaft support portion. The valve body has a valve main body, a rotation shaft portion provided on the valve main body, and a shaft-supported portion provided at an end of the rotation shaft portion and detachably held by the shaft support portion. By removing the shaft-supported portion from the shaft support portion, the valve body can be replaced through the inspection port portion.

[0009] According to the first aspect, a shaft support portion for rotatably holding a valve body is provided above the downstream end of an inflow pipe portion protruding inside a drain mass body. Further, a shaft-supported portion detachably held by the shaft support portion is provided at an end portion of a rotation shaft portion of the valve body. Therefore, by simply removing the shaft-supported portion from the shaft support portion, the valve body can be easily replaced through the inspection port. Further, since the valve body can be replaced only by configuring the shaft-supported portion to be detachable from the shaft support portion, an increase in manufacturing cost can be suppressed.

[0010] According to a second aspect of the present disclosure, in the first aspect, the rotation shaft portion has a substantially cylindrical shaft member and a shaft insertion portion into which the shaft member is inserted. The shaft-supported portion is provided at an end portion of the shaft member. The shaft insertion portion is formed integrally with the valve body and is rotatable while supporting the shaft member.

[0011] According to the second aspect, since the shaft-supported portion does not rotate in principle together with the shaft member, the frictional force generated between the shaft-supported portion and the shaft support portion can be reduced, so that wear of the shaft support portion that is difficult to replace can be suppressed. Further, compared with a configuration in which the shaft-supported portion directly rotates in the shaft support portion, the diameter of the shaft member that is a shaft for supporting the rotation of the valve body can be reduced, so that the contact area of the shaft becomes smaller. For this reason, the frictional force between the shaft member and the shaft insertion portion can be reduced, so that the valve body rotates more easily.

[0012] According to a third aspect of the present disclosure, in the second aspect, the shaft-supported portion is a cap-shaped member having a hole into which an end portion of the shaft member is fitted.

[0013] According to the third aspect, compared with the case where the shaft-supported portion is a donut-shaped member having a through hole, it becomes easier to attach the shaft-supported portion to the shaft member, so that the assembly accuracy of the backflow prevention mass is improved.

[0014] According to a fourth aspect of the present disclosure, in the second or third aspect, the shaft-supported portion and the shaft insertion portion are separated from each other.

[0015] According to the fourth aspect, compared with the case where the shaft-supported portion and the shaft insertion portion are in contact, the friction when the shaft insertion portion rotates can be reduced, and it is possible to prevent the shaft-supported portion from rotating (rotating together) with the shaft insertion portion and increasing the wear between the shaft-supported portion and the shaft support.

[0016] According to the fifth aspect of the present disclosure, in any one of the first to fourth aspects, the shaft support is provided with a concave portion into which the shaft-supported portion is inserted. The concave portion has a tapered shape that widens as it approaches the upper end, and the portion of the concave portion that contacts the shaft-supported portion at the bottom has an arc shape.

[0017] According to the fifth aspect, since the opening side of the concave portion provided in the shaft support is widened, it becomes easier to assemble and disassemble the shaft-supported portion. Further, even when the position of the shaft-supported portion is displaced from the bottom (contact portion) of the concave portion due to the pressure on the valve body when suppressing the backflow of drainage, the shaft-supported portion easily returns to the original contact portion naturally.

[0018] According to the sixth aspect of the present disclosure, in any one of the first to fifth aspects, the valve body has a gripped portion for gripping the valve body during replacement.

[0019] According to the sixth aspect, when replacing the valve body, it is possible to more easily remove and attach the shaft-supported portion to the shaft support.

[0020] According to the seventh aspect of the present disclosure, in any one of the first to sixth aspects, the valve body closes the downstream opening of the inflow pipe portion vertically when there is no drainage.

[0021] According to the seventh aspect, the opening and closing of the valve body during drainage becomes easier. Further, compared with the case where the valve body is inclined when there is no drainage, the valve body is less likely to come off when the backflow of drainage occurs.

[0022] According to the eighth aspect of the present disclosure, in any one of the first to seventh aspects, the hardness of the constituent material of the shaft-supported portion is lower than the hardness of the constituent material of the shaft support.

[0023] According to the eighth aspect, since the shaft-supported part is made of a softer material than the shaft support part, the shaft-supported part can be easily removed from the shaft support part, facilitating the replacement of the valve body. Further, wear of the shaft support part, which is difficult to replace, can be suppressed when assembling the shaft-supported part to the shaft support part, when the valve body operates, and when replacing the valve body.

[0024] According to the ninth aspect of the present disclosure, in any one of the first to eighth aspects, the inflow pipe part has a valve pipe attached from the inside of the drainage mass main body to the downstream side. The shaft support part is provided above the downstream end of the valve pipe. The valve body is configured to be able to close the downstream side opening of the valve pipe.

[0025] According to the ninth aspect, since the valve pipe opened and closed by the valve body is attached from the inside of the drainage mass main body, the valve body can be attached integrally with the valve pipe, facilitating the assembly of the backflow prevention mass.

Advantages of the Invention

[0026] According to the present disclosure, the valve body can be replaced easily and at low cost in the backflow prevention mass.

Brief Description of the Drawings

[0027]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Mode for Carrying Out the Invention

[0028] (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 embodiments shown below, and various modifications can be made without departing from the technical idea of the present disclosure.

[0029] <Drainage pipeline> The backflow prevention mass 10 of the present 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 for example. The backflow prevention mass 10 prevents the intrusion of drainage flowing backward in the drainage pipeline 1 to the upstream side. Between the indoor drainage facility 2 and the backflow prevention mass 10 in the drainage pipeline 1, for example, other drainage masses 3A, 3B, and 3C may be provided to remove dirt such as dust in the drainage pipeline 1 and to inspect the drainage pipeline 1. The pipe constituting the drainage pipeline 1 may be, for example, a vinyl chloride pipe. The drainage pipeline 1 may be provided with a gentle downward slope toward the downstream.

[0030] <Backflow prevention mass> As shown in FIG. 2, the backflow prevention mass 10 includes a drainage mass main body 11, an inspection port portion 11a that opens at the upper part of the drainage mass main body 11, an inflow pipe portion 12 and an outflow pipe portion 13 provided on the side wall of the drainage mass main body 11 for drainage, and a valve body 14 configured to be able to close the downstream opening 12b of the inflow pipe portion 12. The backflow prevention mass 10 may be made of a synthetic resin such as polyvinyl chloride, for example.

[0031] The inspection port 11a has, for example, a circular shape with a diameter of about 50 to 300 mm. By inserting an adjuster for height adjustment and a lid (not shown) into the inspection port 11a, the backflow prevention mass 10 can be faced toward the ground surface, enabling inspection and maintenance of the backflow prevention mass 10.

[0032] The inflow pipe portion 12 includes a first horizontal pipe portion 121 disposed on the upstream side, an inclined pipe portion 122 disposed on the downstream side of the horizontal pipe portion 121, a second horizontal pipe portion 123 disposed on the downstream side of the inclined pipe portion 122, and a valve pipe 124 disposed on the downstream side of the second horizontal pipe portion 123. The first horizontal pipe portion 121, the inclined pipe portion 122, and the second horizontal pipe portion 123 may be integrally formed. The valve pipe 124 is attached from the inside of the drain mass body 11 and is horizontally connected to the second horizontal pipe portion 123. A valve seat surface 12c capable of abutting against the valve body 14 is provided on the downstream end surface of the valve pipe 124.

[0033] The bottom of each of the first horizontal pipe portion 121 and the second horizontal pipe portion 123 (the bottom of the inner wall of the pipe) is horizontal or substantially horizontal. The bottom of the inclined pipe portion 122 slopes downward toward the downstream side. Therefore, the bottom of each of the inclined pipe portion 122 and the second horizontal pipe portion 123 is located below the bottom of the first horizontal pipe portion 121. In other words, the downstream bottom of the inflow pipe portion 12 is located below the upstream bottom of the inflow pipe portion 12.

[0034] Although not shown in the figure, a pipe (upstream pipe on the indoor drainage facility 2 side) that constitutes the drainage pipe 1 is connected to the upstream opening 12a of the inflow pipe portion 12 (first horizontal pipe portion 121). Specifically, the outer diameter of the upstream pipe is substantially equal to the inner diameter of the first horizontal pipe portion 121, and the downstream end of the upstream pipe is inserted into the first horizontal pipe portion 121. A step 121a is provided along the inner circumference of the pipe at the boundary between the first horizontal pipe portion 121 and the inclined pipe portion 122. The inner peripheral surface of the inclined pipe portion 122 may have a curved surface that bulges outward when viewed from the pipe axis of the inclined pipe portion 122. This curved surface can smooth the flow of drainage. The inner diameters of the inclined pipe portion 122 and the second horizontal pipe portion 123 may be substantially equal to the inner diameter of the upstream pipe inserted into the first horizontal pipe portion 121. The tip of the upstream pipe inserted into the first horizontal pipe portion 121 abuts against the step 121a, thereby positioning the upstream pipe in the insertion direction.

[0035] The outer diameter of the second horizontal pipe portion 123 is substantially equal to the diameter of the opening 11b of the drainage mass body 11. The downstream end of the second horizontal pipe portion 123 may be connected to the upstream end of the valve pipe 124, for example, at the position of the opening 11b. A cylindrical portion 11c that protrudes outward from the drainage mass body 11 so as to surround the opening 11b may be provided on the side wall around the opening 11b in the drainage mass body 11, and the second horizontal pipe portion 123 may be inserted into the cylindrical portion 11c. In this case, a protrusion 123a is provided along the outer circumference of the pipe at the boundary between the second horizontal pipe portion 123 and the inclined pipe portion 122. When the second horizontal pipe portion 123 is inserted into the cylindrical portion 11c, the protrusion 123a abuts against the tip of the cylindrical portion 11c, thereby positioning the second horizontal pipe portion 123. Also, if the tip surface of the cylindrical portion 11c is made flat and flush, the tip surface of the cylindrical portion 11c and the protrusion 123a can be brought into surface contact, so that the inflow pipe portion 12 (second horizontal pipe portion 123) and the drainage mass body 11 can be well connected without using a packing or the like.

[0036] The valve pipe 124, that is, at least the downstream end of the inflow pipe portion 12, protrudes into the inside of the drain mass main body 11. The outer diameter of the valve pipe 124 is substantially equal to the diameter of the opening 11b of the drain mass main body 11. An extended portion 111 extending inside the drain mass main body 11 may be provided on the inner wall around the opening 11b in the drain mass main body 11, and the valve pipe 124 may be supported by the extended portion 111. The valve pipe 124 may be adhered to the extended portion 111 in a state of being inserted into the cylindrical extended portion 111.

[0037] The outflow pipe portion 13 may be integrally formed with the drain mass main body 11. The bottom of the drain mass main body 11 and the pipe bottom of the outflow pipe portion 13 may be located at substantially the same height. Although not shown in the figure, a pipe (downstream pipe on the sewer side) constituting the drain pipe 1 is connected to the opening (downstream opening) of the outflow pipe portion 13. Specifically, the outer diameter of the downstream pipe is substantially equal to the inner diameter on the opening side of the outflow pipe portion 13, and the upstream end portion of the downstream pipe is inserted into the outflow pipe portion 13. A step 13a is provided along the inner circumference of the pipe inside the outflow pipe portion 13, and the inner diameter of the outflow pipe portion 13 on the upstream side of the step 13a is smaller than the inner diameter on the opening side of the outflow pipe portion 13, that is, the outer diameter of the downstream pipe. Thereby, the tip of the downstream pipe inserted into the outflow pipe portion 13 abuts against the step 13a, whereby the positioning of the downstream pipe in the insertion direction is performed.

[0038] In addition, in the present embodiment, in order to facilitate the flow of dirt and the like that have passed through the downstream opening 12b of the inflow pipe portion 12 (valve pipe 124) to the downstream side together with the drainage, the bottom of the drain mass main body 11 may be positioned further below the pipe bottom of the valve pipe 124, that is, the downstream pipe bottom of the inflow pipe portion 12. In this case, an inclined portion that inclines downward in the downstream direction from the lower end of the downstream opening 12b of the valve pipe 124 to the bottom of the drain mass main body 11 may be provided in the drain mass main body 11. Further, a horizontal portion that connects to the inclined portion and supports the valve pipe 124, and a support portion that supports the horizontal portion and is located below the opening 11b of the drain mass main body 11 may be provided in the drain mass main body 11, respectively.

[0039] Further, an inverted portion 11d having a substantially semi-circular cross-section, for example, may be provided at the bottom of the drain mass body 11. The bottom of the inverted portion 11d and the bottom of the outflow pipe portion 13 may be located at substantially the same height. The inverted portion 11d may be provided to extend along an inclined portion from the bottom of the drain mass body 11 to the downstream opening 12b of the valve pipe 124. By doing so, since the inflow pipe portion 12 and the outflow pipe portion 13 are connected by the inverted portion 11d, it is possible to prevent dirt and the like in the drainage from staying.

[0040] Further, the inclination of the inclined pipe portion 122 may be set such that the height difference between the bottom of the first horizontal pipe portion 121 and the bottom of the second horizontal pipe portion 123 (that is, the bottom of the valve pipe 124) is equal to or greater than about 1 / 4 of the inner diameter of the upstream pipe (the pipe connected to the inflow pipe portion 12 from the upstream side). Alternatively, the inclination of the inclined pipe portion 122 may be set such that the extension line of the central axis of the first horizontal pipe portion 121 passes through the downstream opening 12b of the valve pipe 124 without intersecting the inner wall surface of the inclined pipe portion 122. In other words, the height difference between the bottom of the first horizontal pipe portion 121 and the bottom of the valve pipe 124 (the second horizontal pipe portion 123) may be set to less than 50% of the inner diameter of the inclined pipe portion 122 (the inner diameter of the upstream pipe).

[0041] <Valve body and shaft support portion> As shown in FIGS. 2 to 5, a shaft support portion 15 is provided above the valve pipe 124, that is, the downstream end of the inflow pipe portion 12, and a valve body 14 is rotatably held by the shaft support portion 15. The shaft support portion 15 may be integrally formed with the valve pipe 124 at the top of the valve pipe 124.

[0042] The valve body 14 mainly includes a valve body 141 and a rotation shaft portion 143. The valve body 141 is configured in a substantially disc shape so as to be able to close the downstream opening 12b of the inflow pipe portion 12. A connection portion 141a for connecting to the rotation shaft portion 143 is provided at the upper part of the valve body 141. At both ends of the rotation shaft portion 143, shaft support portions 144 that are detachably held by the shaft support portion 15 are provided.

[0043] In this embodiment, the center of gravity of the valve body 141 is located on the downstream side of the rotation shaft portion 143, and the connecting portion 141a has a shape bent upstream from the valve body 141 toward the rotation shaft portion 143. The connecting portion 141a serves as a gripped portion for gripping the valve body 14 when the valve body 14 is replaced. The connecting portion 141a and the gripped portion may be provided separately.

[0044] The opening surface of the downstream opening 12b of the inflow pipe portion 12 (valve pipe 124) is substantially a vertical plane, and the valve body 141 substantially vertically closes the downstream opening 12b along this vertical plane when there is no drainage. That is, the angle formed by the disk shape of the valve body 141 with the vertical plane when closing the downstream opening 12b is substantially 0°. A valve seat surface 12c capable of abutting against the valve body 141 is provided at the end surface on the downstream side of the inflow pipe portion 12, that is, at the peripheral edge 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 during backflow of drainage. The valve seat surface 12c may be provided in a flaring shape in the downstream direction from the inner peripheral surface to the end surface of the inflow pipe portion 12 (valve pipe 124). That is, the valve seat surface 12c may be a tapered surface (inclined surface). An annular packing 16 capable of closely adhering to the valve seat surface 12c of the inflow pipe portion 12 is provided on the outer peripheral surface of the valve body 141. The packing 16 may be, for example, a V-packing. In this way, the adhesion of the packing 16 to the valve seat surface 12c is improved, and the water-stopping effect by the valve body 141 during backflow of drainage is increased.

[0045] The rotation shaft portion 143 is composed of, for example, a substantially columnar shaft member 145 and a shaft insertion portion 146 having a through hole 146a into which the shaft member 145 is inserted. The shaft supported 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 integrally formed with the valve body 141 (connecting 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. Thereby, the shaft insertion portion 146 can rotate together with the valve body 141 with the shaft member 145 as a support. The shaft insertion portion 146 and the shaft supported portion 144 may be separated.

[0046] The shaft-supported part 144 may be, for example, a columnar 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 shaft-supported part 144 may have a tapered shape with a narrower back side. This makes it easier to press-fit the shaft member 145 into the hole 144a of the shaft-supported part 144 when attaching the shaft-supported part 144 to the shaft member 145, and also makes it difficult for the shaft-supported part 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 can be bitten into the shaft-supported part 144, thereby facilitating the positioning and fixing of both.

[0047] A recess 15a into which the shaft-supported part 144 is inserted is provided in the shaft support 15. The recess 15a has, for example, a tapered shape that widens towards the upper end, and the part of the bottom of the recess 15a that contacts the shaft-supported part 144 has an arc shape corresponding to the shape of the shaft-supported part 144. Incidentally, as shown in FIG. 5, the shaft support 15 may have a pedestal 15b that connects to the valve pipe 124. Also, a convex part 124a used for aligning the drain mass body 11 and the valve body 124 may be provided integrally with the pedestal 15b at the top of the valve pipe 124.

[0048] In this embodiment, the shaft-supported part 144 remains placed in the recess 15a of the shaft support 15 without taking any other fixing means. For this reason, the workability when attaching the valve body 14 or when replacing the valve body 14 is improved. On the other hand, due to the self-weight of the valve body 14 itself (for example, about 100 g), even if the shaft-supported part 144 is displaced within the recess 15a of the shaft support 15, the shaft-supported part 144 naturally returns to its original position (the bottom of the recess 15a). Also, when there is no drainage, the valve body 141 fits into the valve pipe 124 side due to the effect of the packing (V-packing), so displacement of the shaft-supported part 144 within the recess 15a is unlikely to occur. Furthermore, during backflow prevention, since the valve body 141 adheres strongly to the valve seat surface 12c of the inflow pipe part 12 (valve pipe 124), displacement of the shaft-supported part 144 within the recess 15a becomes even less likely to occur.

[0049] Also, in the present embodiment, since the bottom of the recess 15a has a curvature that fits the cap-shaped shaft-supported portion 144, the shaft-supported portion 15 and the shaft-supported portion 144 are in surface contact. On the other hand, in the rotation shaft portion 143 of the valve body 14, the shaft member 145 provided with the shaft-supported portion 144 and the through-hole 146a of the shaft insertion portion 146 have different diameters from each other, so they are basically in line contact. Therefore, since the frictional force between the shaft-supported portion 15 and the shaft-supported portion 144 is greater than the frictional force between the shaft member 145 and the shaft insertion portion 146, the shaft insertion portion 146 can rotate together with the valve body 141 while supporting the shaft member 145.

[0050] In addition, for example, when the shaft member 145 and the shaft insertion portion 146 (through-hole 146a) are fixed due to aging deterioration or the like, in other words, when the shaft insertion portion 146 (valve body 141) cannot rotate with the shaft member 145 as a support, since the bottom of the recess 15a has an arc shape, the columnar shaft-supported portion 144 can rotate within the recess 15a.

[0051] In the above description, as the shaft-supported portion 144, a columnar cap member is used, and the contact portion of the recess 15a with the shaft-supported portion 144 has an arc shape. Instead of this, the shaft-supported portion 144 may be configured in a shape having corners (for example, a rectangular parallelepiped shape), and the shape of the recess 15 may also be a shape adapted to the shaft-supported portion 144. In this case, when the shaft member 145 and the shaft insertion portion 146 are fixed, the shaft-supported portion 144 cannot be rotated within the recess 15a, but since the shaft-supported portion 144 becomes difficult to move within the recess 15a, wear of the shaft-supported portion 15, which is difficult to replace, can be suppressed.

[0052] In this embodiment, it is preferable that the hardness of the constituent material of the shaft-supported portion 144 is lower than the hardness of the constituent material of the shaft support portion 15. For example, the shaft-supported portion 144 may be made of a polyethylene resin or a polyethylene-based elastomer, and the shaft support portion 15 may be made of a rigid polyvinyl chloride resin. Thus, when the shaft-supported portion is made of a softer material than the shaft support portion 15, the shaft-supported portion 144 can be easily removed from the shaft support portion 15, facilitating the replacement of the valve body 14. Also, when assembling the shaft-supported portion 144 to the shaft support portion 15, during the operation of the valve body 14, or when replacing the valve body 14, wear of the shaft support portion 15, which is difficult to replace, can be suppressed. Furthermore, even if the shaft member 145 and the shaft insertion portion 146 become fixed and the shaft-supported portion 144 rotates within the recess 15a of the shaft support portion 15, the self-lubricating property, which is a characteristic of plastic, is exhibited, suppressing wear of the shaft support portion 15 and also limiting wear of the shaft-supported portion 144, and enabling the service life (e.g., 10 years) of the valve body 14 to be satisfied.

[0053] <Operation of the backflow prevention mass> When there is no drainage, the valve body 141 contacts the valve seat surface 12c of the inflow pipe portion 12, closing the downstream opening 12b of the inflow pipe portion 12. When drainage flows out from the indoor drainage facility 2 while the valve body 141 is closing the downstream opening 12b, the drainage that has flowed into the inflow pipe portion 12 through the drainage pipe 1 presses open the valve body 141 that is in contact with the valve seat surface 12c of the inflow pipe portion 12 by water pressure. As a result, drainage flows from the inflow pipe portion 12 into the drainage mass main body 11, and the drainage flows out from the backflow prevention mass 10 through the outflow pipe portion 13. Also, since the center of gravity of the valve body 141 is located downstream of the rotation shaft portion 143, when the drainage in the inflow pipe portion 12 flows away, the valve body 141 closes the downstream opening 12b again by its own weight.

[0054] On the other hand, even if drainage that has overflowed beyond the drainage capacity of the sewer pipe due to heavy rain or the like flows back through the drainage pipe 1, since the downstream opening 12b of the inflow pipe portion 12 is closed by the valve body 141, drainage does not penetrate into the drainage pipe 1 upstream of the valve body 14. Therefore, it is possible to prevent the backflowed drainage and the air pumped by this drainage from spraying out from the indoor drainage facility 2.

[0055] <Replacement of the valve body> In this embodiment, by removing the shaft-supported portion 144 of the valve body 14 from the shaft support portion 15 (recess 15a), the valve body 14 can be replaced through the inspection port portion 11a. At this time, the center of gravity of the valve body main body 141 is located on the downstream side of the rotation shaft portion 143 where the shaft-supported portion 144 is provided. In other words, the connecting portion 141a that connects the valve body main body 141 and the rotation shaft portion 143 has a shape that bends upstream from the valve body main body 141 toward the rotation shaft portion 143. For this reason, while avoiding interference between the packing 16 of the valve body 14 and the valve pipe 124, the replacement of the valve body 14 (removal of the old valve body 14 and attachment of the new valve body 14) can be easily performed. Also, as described above, by forming the shaft-supported portion 144 with a softer material than the shaft support portion 15, the shaft-supported portion 144 can be easily removed from the shaft support portion 15, making the replacement of the valve body 14 even easier, and wear of the shaft support portion 15 that is difficult to replace can be suppressed. Furthermore, when the backflow prevention mass 10 is buried deep underground and it is necessary to use a jig (for example, a magic hand) for replacing the valve body 14, the connecting portion 141a (the portion to be gripped) is gripped by the jig for replacement. At this time, even if the valve body 14 and the shaft support portion 15 come into contact outside the predetermined position, the shaft support portion 15 is less likely to be damaged.

[0056] <Features of the embodiment> As described above, according to the backflow prevention mass 10 of this embodiment, a shaft support portion 15 for rotatably holding the valve body 14 is provided on the valve pipe 124 (the downstream end of the inflow pipe portion 12) protruding inside the drain mass main body 11. Also, a shaft-supported portion 144 that is detachably held by the shaft support portion 15 is provided at the end of the rotation shaft portion 143 of the valve body 14. For this reason, by simply removing the shaft-supported portion 144 from the shaft support portion 15, the valve body 14 can be easily replaced through the inspection port portion 11a. Also, since the valve body 14 can be replaced simply by configuring the shaft-supported portion 144 to be detachable from the shaft support portion 15, an increase in manufacturing cost can be suppressed.

[0057] In the backflow prevention mass 10 of the present embodiment, the rotation shaft portion 143 of the valve body 14 may include a substantially cylindrical shaft member 145 and a shaft insertion portion 146 into which the shaft member 145 is inserted. The shaft support portion 144 may be 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 while supporting the shaft member 145. By doing so, the shaft support portion 144 and the shaft member 145 will not rotate in principle, and the frictional force generated between the shaft support portion 144 and the shaft support 15 can be reduced, so that wear of the shaft support 15, which is difficult to replace, can be suppressed. Further, compared with a configuration in which the shaft support portion 144 directly rotates in the shaft support 15, the diameter of the shaft member 145, which is the shaft supporting the rotation of the valve body 141, can be reduced, so that the contact area of the shaft becomes smaller. For this reason, the frictional force between the shaft member 145 and the shaft insertion portion 146 can be reduced, and the valve body 141 becomes easier to rotate.

[0058] In the backflow prevention mass 10 of the present embodiment, the shaft support portion 144 may be a cap-shaped member having a hole 144a into which the end of the shaft member 145 is fitted. By doing so, compared with the case where the shaft support portion 144 is a donut-shaped member having a through hole, it becomes easier to attach the shaft support portion 144 to the shaft member 145, and thus the assembly accuracy of the backflow prevention mass 10 is improved.

[0059] In the backflow prevention mass 10 of the present embodiment, the shaft support portion 144 and the shaft insertion portion 146 may be separated. By doing so, compared with the case where the shaft support portion 144 and the shaft insertion portion 146 are in contact, the friction when the shaft insertion portion 146 rotates can be reduced, and it is possible to prevent the shaft support portion 144 from rotating (co-rotating) together with the shaft insertion portion 146 and increasing the wear between the shaft support portion 144 and the shaft support 15.

[0060] In the backflow prevention mass 10 of the present embodiment, the shaft support portion 15 may be provided with a recess 15a into which the supported shaft support portion 144 is inserted. The recess 15a has a tapered shape that widens as it approaches the upper end, and the portion of the recess 15a that contacts the supported shaft support portion 144 at the bottom may have an arc shape. By doing so, since the opening side of the recess 15a provided in the shaft support portion 15 is widened, it becomes easier to assemble and disassemble the supported shaft support portion 144. Further, even when the position of the supported shaft support portion 144 deviates from the bottom (contact portion) of the recess 15a due to the pressure on the valve body 14 when suppressing the backflow of drainage, the supported shaft support portion 144 easily returns to the original contact portion naturally.

[0061] In the backflow prevention mass 10 of the present embodiment, the valve body 14 may have a gripped portion (connection portion 141a) for gripping the valve body 14 during replacement. By doing so, when replacing the valve body 14, it is possible to more easily remove and attach the supported shaft support portion 144 to the shaft support portion 15.

[0062] Further, in the backflow prevention mass 10 of the present embodiment, the valve body 141 may substantially vertically close the downstream opening 12b of the inflow pipe portion 12 when there is no drainage. By doing so, the opening and closing of the valve body 141 during drainage becomes easy. Further, compared to the case where the valve body 141 is inclined when there is no drainage, the valve body 14 is less likely to come off when backflow of drainage occurs.

[0063] Further, in the backflow prevention mass 10 of the present embodiment, the hardness of the material constituting the supported shaft support portion 144 may be lower than the hardness of the material constituting the shaft support portion 15. By doing so, since the supported shaft support portion 144 is made of a softer material than the shaft support portion 15, it becomes easier to remove the supported shaft support portion 144 from the shaft support portion 15, and thus it becomes easier to replace the valve body 14. Further, it is possible to suppress wear of the shaft support portion 15, which is difficult to replace, during assembly of the supported shaft support portion 144 to the shaft support portion 15, during operation of the valve body 14, and during replacement of the valve body 14.

[0064] Also, in the backflow prevention mass 10 of the present embodiment, the inflow pipe portion 12 may have a valve pipe 124 attached from the inside of the drainage mass body 11 to the downstream side. A shaft support portion 15 may be provided above 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. By doing so, since the valve pipe 124 opened and closed by the valve body 14 is attached from the inside of the drainage mass body 11, the valve body 14 can be attached integrally with the valve pipe 124, facilitating the assembly of the backflow prevention mass 10.

[0065] In addition, the backflow prevention mass 10 of the present embodiment may have the following characteristics.

[0066] In the inflow pipe portion 12 of the drainage provided on the side wall of the drainage mass body 11, the downstream pipe bottom may be located below the upstream pipe bottom. By doing so, when the drainage flows from the upstream side to the downstream side of the inflow pipe portion 12, the flow velocity of the drainage increases, so that the valve body 141 of the valve body 14 that closes the downstream opening 12b of the inflow pipe portion 12 is likely to be opened by the flow of the drainage. Therefore, even when the amount of drainage is small, it is possible to suppress the occurrence of drainage blockage due to dirt or the like in the backflow prevention mass 10. In particular, this configuration is useful when the flow gradient of the pipe connected to the inflow pipe portion 12 from the upstream side is small and the flow velocity of the drainage in the pipe is small.

[0067] The bottom of the drainage mass body 11 may be located below the downstream pipe bottom of the inflow pipe portion 12. By doing so, it is possible to avoid a situation where dirt or the like accumulates on the downstream side of the valve body 141 in the drainage mass body 11 and inhibits the opening of the valve body 141. Therefore, it is possible to further suppress the occurrence of drainage blockage due to dirt or the like in the backflow prevention mass 10.

[0068] The height difference between the downstream pipe bottom and the upstream pipe bottom in the inflow pipe portion 12 may be about 1 / 4 or more of the inner diameter of the pipe connected to the upstream side of the inflow pipe portion 12. By doing so, when the drainage flows from the upstream side to the downstream side of the inflow pipe portion 12, the flow velocity of the drainage can be sufficiently increased, so that the valve body 141 is more likely to open due to the flow of the drainage. Therefore, it is possible to further suppress the occurrence of drainage blockage due to dirt or the like in the backflow prevention mass 10.

[0069] The inflow pipe portion 12 may include a first horizontal pipe portion 121 disposed on the upstream side and having a pipe bottom that is horizontal or substantially horizontal, and an inclined pipe portion 122 disposed on the downstream side of the first horizontal pipe portion 121 and having a pipe bottom that inclines downward toward the downstream side. By doing so, the pipe connected to the upstream side of the inflow pipe portion 12 can be easily connected to the first horizontal pipe portion 121 of the inflow pipe portion 12.

[0070] The inflow pipe portion 12 may further include a second horizontal pipe portion 123 disposed on the downstream side of the inclined pipe portion 122, connected to the drainage mass body 11, and having a pipe bottom that is horizontal or substantially horizontal. By doing so, the second horizontal pipe portion 123 of the inflow pipe portion 12 can be easily attached to the side wall of the drainage mass body 11.

[0071] The extension line of the axis of the first horizontal pipe portion 121 may pass through the downstream opening 12b of the inflow pipe portion 12 without intersecting the inner wall surface of the inclined pipe portion 122. By doing so, when the drainage flows from the upstream side to the downstream side of the inflow pipe portion 12, it is possible to avoid a situation where the drainage collides near the pipe top (the top of the pipe inner wall) of the inclined pipe portion 122 and the flow velocity of the drainage decreases. Therefore, the valve body 141 can be brought into a state where it is easily opened by the flow of the drainage.

[0072] The first horizontal pipe portion 121, the inclined pipe portion 122, and the second horizontal pipe portion 123 may be integrally formed. By doing so, the number of components of the backflow prevention mass 10 can be reduced, so that the assembly of the backflow prevention mass 10 becomes easy.

[0073] (Modification 1) The point where Modification Example 1 differs from the above-described embodiment is the structure of the rotation shaft portion 143 and the shaft-supported portion 144 of the valve body 14, as shown in FIG. 7. Note that in FIG. 7, only one end side of the rotation shaft portion 143 is illustrated. In FIG. 7, the same reference numerals are assigned to the same components as those in the above-described embodiment shown in FIGS. 2 to 5.

[0074] In Modification Example 1, the end portion 143a of the rotation shaft portion 143 is thinner than other portions, and the end portion 143a is rotatably inserted into the through hole of the donut-shaped shaft-supported portion 144. That is, in Modification Example 1, the rotation shaft portion 143 and the valve body 141 are configured to be rotatable while supporting the shaft-supported portion 144.

[0075] The shaft-supported portion 144 is placed in a semi-fixed state in the concave portion 15a of the shaft support portion 15. In other words, a clearance is provided between the shaft-supported portion 144 and the concave portion 15a. The shaft-supported portion 144 may rotate at a speed slower than that of the rotation shaft portion 143 while receiving the rotation torque of the rotation shaft portion 143 (end portion 143a). An anti-disengagement member 147 for preventing the shaft-supported portion 144 from coming off may be provided at the end portion 143a of the rotation shaft portion 143.

[0076] Also in Modification Example 1, the same effects as those of the above-described embodiment can be obtained. That is, by simply removing the shaft-supported portion 144 from the shaft support portion 15, the valve body 14 can be easily replaced through the inspection port 11a. Further, since the valve body 14 can be replaced only by configuring the shaft-supported portion 144 to be detachable from the shaft support portion 15, an increase in manufacturing cost can be suppressed.

[0077] Also in Modification Example 1, the hardness of the constituent material of the shaft-supported portion 144 is preferably lower than the hardness of the constituent material of the shaft support portion 15. For example, the shaft-supported portion 144 may be made of a polyethylene resin or a polyethylene-based elastomer, and the shaft support portion 15 may be made of a rigid polyvinyl chloride resin. Thus, when the shaft-supported portion is made of a softer material than the shaft support portion 15, the shaft-supported portion 144 can be easily removed from the shaft support portion 15, facilitating the replacement of the valve body 14. Further, wear of the shaft support portion 15, which is difficult to replace, can be suppressed when the shaft-supported portion 144 is assembled to the shaft support portion 15, during the operation of the valve body 14, or when the valve body 14 is replaced. Furthermore, even when the shaft-supported portion 144 rotates within the concave portion 15a of the shaft support portion 15, the self-lubricating property, which is a characteristic of plastic, is exhibited, suppressing wear of the shaft support portion 15 and also limiting wear of the shaft-supported portion 144, enabling the service life (e.g., 10 years) of the valve body 14 to be satisfied.

[0078] (Modification Example 2) The difference between Modification Example 2 and the above-described embodiment is that, as shown in FIG. 8, the inflow pipe portion 12 is configured without using the valve pipe 124, in other words, the downstream side (second horizontal pipe portion 123) of the inflow pipe portion 12 is inserted into the inside of the drain mass body 11. In FIG. 8, the same reference numerals are assigned to the same components as those in the embodiment shown in FIG. 2.

[0079] In Modification Example 2, the second horizontal pipe portion 123 is inserted from the outside to the inside of the drain mass body 11 through the opening 11b in the side wall of the drain mass body 11, thereby connecting the drain mass body 11 and the inflow pipe portion 12. The outer diameter of the second horizontal pipe portion 123 is substantially equal to the diameter of the opening 11b of the drain mass body 11. The downstream opening 12b of the inflow pipe portion 12 (second horizontal pipe portion 123) is located on the inner side of the drain mass body 11 relative to the opening 11b of the drain mass body 11. A valve seat surface 12c capable of abutting against the valve body 141 is provided on the end surface of the second horizontal pipe portion 123. When the second horizontal pipe portion 123 is inserted into the opening 11b, the protrusion 123a of the second horizontal pipe portion 123 abuts against the side wall (cylindrical portion 11c) around the opening 11b in the drain mass body 11, thereby positioning the second horizontal pipe portion 123 in the insertion direction.

[0080] On the upper side of the opening 11b on the inner wall of the drainage mass body 11, an extended portion 111 extending inwardly of the drainage mass body 11 along the outer peripheral top of the second horizontal pipe portion 123 may be provided. The shaft support portion 15 may be fixed on the extended portion 111 by a method such as adhesion, screwing, or welding. The rotating shaft portion 143 pivotally supported by the shaft support portion 15 is disposed on the upstream side of the center of gravity position of the valve body 141. The extended portion 111 may be integrally formed with the drainage mass body 11.

[0081] According to Modification 2, since the downstream side of the inflow pipe portion 12 is inserted into the drainage mass body 11, the configuration of the inflow pipe portion 12 is simplified and the assembly of the backflow prevention mass 11 becomes easy.

[0082] (Other Embodiments) In the above-described embodiments (including modifications. The same shall apply hereinafter), the backflow prevention mass 10 is provided in the drainage pipeline 1 configured in series. However, the present invention is not limited thereto, and for example, the backflow prevention mass 10 may be provided in a drainage pipeline including a plurality of pipes configured in parallel using a drainage header or the like.

[0083] Further, in the above-described embodiments, one inflow pipe portion 12 and one outflow pipe portion 13 for drainage are provided on the side wall of the drainage mass body 11. However, the present invention is not limited thereto, and a plurality of inflow pipe portions 12 or a plurality of outflow pipe portions 13 may be provided on the side wall of the drainage mass body 11.

[0084] Further, in the above-described embodiments, the inflow pipe portion 12 is composed of the first horizontal pipe portion 121, the inclined pipe portion 122, the second horizontal pipe portion 123, and the valve pipe 124. However, the configuration of the inflow pipe portion 12 is not particularly limited. For example, the first horizontal pipe portion and / or the second horizontal pipe portion 123 may not be provided. Alternatively, a third horizontal pipe portion may be provided in the middle of the inclined pipe portion 122.

[0085] Further, in the above-described embodiments, the inflow pipe portion 12 and the drainage mass body 11 are separate bodies, but instead, the inflow pipe portion 12 excluding the valve pipe 124 and the drainage mass body 11 may be integrally formed.

[0086] In the above embodiment, the shaft support portion 15 and the valve pipe 124 are integrally formed. Alternatively, the shaft support portion 15 may be removably fixed to the valve pipe 124 by screws or the like. By making the shaft support portion 15 removable, it can be replaced even if the shaft support portion 15 is damaged.

[0087] Although the embodiments have been described above, it will be understood that various changes in form and detail can be made without departing from the spirit and scope of the claims. Also, the above embodiments may be combined or replaced as appropriate as long as the functions of the subject of the present disclosure are not impaired. Furthermore, the descriptions such as "first", "second",... described above are used to distinguish the phrases to which these descriptions are given, and do not limit even the number and order of those phrases.

Explanation of Reference Numerals

[0088] 1 Drainage pipe 2 Indoor drainage facility 3A, 3B, 3C Drainage mass 10 Backflow prevention mass 11 Drainage mass body 11a Inspection port portion 11b Opening 11c Cylindrical portion 11d Invert portion 111 Extension portion 12 Inflow pipe portion 12a Upstream opening 12b Downstream opening 12c Valve seat surface 121 First horizontal pipe portion 121a Step 122 Inclined pipe portion 123 Second horizontal pipe portion 123a Protrusion 124 Valve pipe 124a Convex portion 13 Outflow pipe portion 13a Step 14 Valve body 141 Valve body 141a Connection portion 143 Rotating shaft portion 144 Shaft support portion to be supported 144a hole 145 shaft member 146 shaft insertion part 146a through hole 147 anti-disengagement 15 shaft support 15a recess 15b pedestal 16 packing

Claims

1. A backflow prevention mass provided in a drainage pipeline connecting an indoor drainage facility and a sewer pipe, for preventing the intrusion of drainage flowing backward in the drainage pipeline into the upstream side, comprising: a drainage mass body; an inspection port portion opening at the upper part of the drainage mass body; an inflow pipe portion and an outflow pipe portion for drainage provided on the side wall of the drainage mass body; a valve body configured to be able to close the downstream opening of the inflow pipe portion; and comprising; at least the downstream end of the inflow pipe portion protrudes into the interior of the drainage mass body; a shaft support portion is provided above the downstream end of the inflow pipe portion, and the valve body is rotatably held by the shaft support portion; the inflow pipe portion includes a horizontal pipe portion connected to the drainage mass body and having a horizontal or substantially horizontal pipe bottom, and an inclined pipe portion arranged upstream of the horizontal pipe portion and having a pipe bottom inclined downward toward the downstream side; the valve body; a valve main body; a rotation shaft portion provided on the valve main body; a shaft-supported portion provided at the end of the rotation shaft portion and detachably held by the shaft support portion; and having; a recess into which the shaft-supported portion is inserted is provided in the shaft support portion; by removing the shaft-supported portion from the shaft support portion, the valve body can be replaced through the inspection port portion; a backflow prevention mass.

2. The rotation shaft portion; a substantially columnar shaft member; and a shaft insertion portion into which the shaft member is inserted; and having; the shaft-supported portion is provided at the end of the shaft member; the shaft insertion portion is formed integrally with the valve main body and is rotatable with the shaft member as a support; the backflow prevention mass according to Claim 1.

3. The shaft-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.

4. The shaft-supported portion and the shaft insertion portion are separated from each other; the backflow prevention mass according to Claim 2 or 3.

5. 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 shaft-supported portion has an arc shape; the backflow prevention mass according to any one of Claims 1 to 4.

6. The valve body has a gripped portion for gripping the valve body during replacement; the backflow prevention mass according to any one of Claims 1 to 5.

7. The valve main body vertically closes the downstream opening of the inflow pipe portion when there is no drainage; the backflow prevention mass according to any one of Claims 1 to 6.

8. The hardness of the constituent material of the shaft-supported portion is lower than the hardness of the constituent material of the shaft support portion; The backflow prevention mass according to any one of claims 1 to 7.

9. The inflow pipe portion has a valve pipe attached from the inside of the drain mass body on the downstream side, The shaft support portion is provided above the downstream end of the valve pipe, The valve body is configured to be able to close the downstream side opening of the valve pipe, The backflow prevention mass according to any one of claims 1 to 8.

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