JP7525326B2 - Backflow prevention device - Google Patents

Description

The present invention relates to a backflow prevention device that can prevent odor leakage.

A rainwater manhole is known from the prior art, for example as described in Patent Document 1 below. This conventional rainwater manhole has a manhole body, and a riser pipe is connected to the cleaning port of this manhole body. A lid receiver is fitted to the upper end of this riser pipe, and a lid is removably attached to this lid receiver. A mud collection container and a net are also provided within the manhole body.

Japanese Utility Model Application Publication No. 6-76484

However, with the above-mentioned conventional rainwater catch basins, odors may be generated depending on the maintenance conditions, etc., and there is a risk that this odor may leak outside.

The present invention has been developed in consideration of these points, and aims to provide a backflow prevention device that can prevent odor leakage.

The backflow prevention device described in claim 1 is a backflow prevention device that is attached to a pipeline having a lid through which wastewater generated outdoors flows into a pipeline, and a lid receiving part onto which the lid is detachably fitted and whose inner diameter is smaller than the inner diameter of the pipeline, and is composed of a contractible and expandable elastic member and comprises a mounting body that is attached to a part of the pipeline below the lid, and a valved main body that is attached to the mounting body and has a backflow prevention valve that prevents the backflow of odors , and the mounting body is capable of elastic deformation by contracting so that its outer diameter is larger than the inner diameter of the pipeline and smaller than the inner diameter of the lid receiving part .

The backflow prevention device according to the second aspect of the present invention is the backflow prevention device according to the first aspect, wherein the valve-equipped main body is detachably attached to the mounting body via a seal member.

The backflow prevention device of claim 3 is a backflow prevention device of claim 2 , in which the sealing member is attached to the mounting body so that its outer peripheral side is in close contact with the inner peripheral surface of the pipeline, and the valve-equipped main body is removably attached to the inner peripheral side of the sealing member.

The backflow prevention device of claim 4 is a backflow prevention device of any one of claims 1 to 3 , in which the valved main body has an inverted truncated cone-shaped guide portion that guides drainage toward the backflow prevention valve located on the reduced diameter side.

The backflow prevention device according to claim 5 is the backflow prevention device according to any one of claims 1 to 4 , wherein the valved main body has a grip part at least a part of which is located above the backflow prevention valve.

A backflow prevention device according to a sixth aspect of the present invention is a backflow prevention device according to any one of the first to fifth aspects, wherein the valved main body is capable of being inserted into and removed from the pipeline.

The present invention makes it possible to prevent odor leakage.

1 is a cross-sectional view of a manhole device equipped with a backflow prevention device according to a first embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view of a portion of FIG. 1 . FIG. FIG. 1A is a plan view of the valved main body, FIG. 1B is a plan view of the elastic packing, and FIG. 1C is a plan view of the fixed body. 4A to 4C are diagrams showing the installation procedure of the backflow prevention device. 7(d) to (f) are diagrams showing the construction procedure following FIG. 6. 8(g) to 8(i) are diagrams showing the construction procedure following FIG. 7. 11A to 11D are diagrams showing the procedure for removing the mud basin container. 1A and 1B are diagrams showing a backflow prevention device according to a second embodiment of the present invention, in which FIG. 13A and 13B are diagrams showing a backflow prevention device according to a third embodiment of the present invention, in which FIG. 13A is a cross-sectional view and FIG. FIG. 10 is a cross-sectional view showing a backflow prevention device according to a fourth embodiment of the present invention. FIG. 2 is an exploded perspective view showing the backflow prevention device. FIG. 13 is a perspective view showing a modified example of the grip portion of the valved body.

The first embodiment of the present invention will be described with reference to Figures 1 to 9.

In Figures 1 and 2, 1 is a manhole device, which is equipped with a rainwater manhole 2, which is a drainage manhole into which rainwater, which is wastewater generated outdoors, flows, and a backflow prevention device 3 attached to the rainwater manhole 2.

In addition, this illustrated example is an example in which a backflow prevention device 3 for preventing odor leakage has been retrofitted (retrofitting work that does not require special tools) to an existing rainwater manhole 2 buried underground in order to prevent odors from leaking out of the manhole 2 and to prevent pests (mosquitoes, etc.) from escaping to the outside.

The rainwater manhole 2 comprises a manhole body 6, a riser pipe 7 which is a vertical pipe erected on the manhole body 6, a lid receiving body 8 attached to the upper end of the riser pipe 7, and a lid 9 which is removably attached to the lid receiving body 8.

The manhole body 6 has an inlet section 11, an outlet section 12, a cleaning port section 13, and a mud basin section 14. The downstream end of an inlet pipe 16 is connected to the inlet section 11, the upstream end of an outlet pipe 17 is connected to the outlet section 12, and the lower end of a riser pipe 7, which is a cleaning pipe that rises upward, is connected to the cleaning port section 13.

A mud basin container 18, which is a container body with an open top, is disposed in the mud basin section 14. The mud basin container 18 has a cylindrical container body 19 with a bottom that is stored in the mud basin section 14 so that it can be inserted and removed, and a handle 20 attached to the upper end of the container body 19. The outer diameter of the container body 19 of the mud basin container 18 is slightly smaller than the inner diameter of the support portion 25 of the lid receiving body 8.

The lid receiving body 8 has an insertion part 21 inserted and fixed to the inner periphery of the upper end of the riser pipe 7, and a lid receiving part 22 to which the lid 9 is removably fitted. The lid receiving part 22 has an opening 23 that is closed by the disk-shaped lid 9 in an openable and closable manner, and this opening 23 is composed of the upper part of the internal space 24 of the short cylindrical lid receiving body 8. The lid receiving part 22 also has an inwardly protruding, annular support part 25 that receives and supports the lower surface of the lid 9. The inner diameter of this support part 25 is smaller than the inner diameter of the riser pipe 7. Note that the lid receiving body 8 is not limited to a configuration having an insertion part 21, which is a connection part connected to the inner periphery of the upper end of the riser pipe 7, and may be a configuration having a connection part (receiving port) connected to the outer periphery of the upper end of the riser pipe 7, etc.

The lid 9 has multiple water holes 28 that penetrate the top and bottom surfaces of the lid 9. Then, for example, rainwater, which is drainage generated outdoors during rainy weather, flows through the water holes 28 of the lid 9 into the riser pipe 7, which is a cylindrical pipe. The lid 9 is attached to the inner side of the lid receiving portion 22 of the lid receiving body 8 so that its top surface is located on the same plane as the ground surface.

The backflow prevention device 3 is primarily intended to prevent the leakage of odors, and as shown in Figures 3 to 5, it is equipped with a fixed body 31, which is a mounting body that is fixed to the inner circumferential surface of the riser pipe 7 of the rainwater manhole 2 below the lid 9, for example, and a valved body 33 that is detachably attached to the fixed body 31 via an elastic packing 32, which is a circular sealing member, and has a backflow prevention valve 35 that prevents the backflow of odors and pests in the rainwater manhole 2.

As is clear from Fig. 4, the backflow prevention device 3 comprises a fixed body 31, a valved body 33 consisting of a backflow prevention valve 35 and a body member 36 that holds it, and an annular elastic packing 32 provided between the fixed body 31 and the valved body 33. The fixed body 31 and the body member 36 are made of, for example, a synthetic resin, and the elastic packing 32 and the backflow prevention valve 35 are made of, for example, an elastic material that can be elastically deformed.

The fixed body 31 is fixed to the inner peripheral surface of the riser pipe 7, and an elastic packing 32 is attached to this fixed body 31 so that its outer peripheral side is in close contact with the inner peripheral surface of the riser pipe 7 at a position above the fixed body 31, and a valved body 33 is detachably attached to the inner peripheral side of this attached elastic packing 32. Note that the valved body 33 can be inserted and removed from the riser pipe 7 via the internal space 24 of the lid receiving body 8, for example, for maintenance (inspection, cleaning, etc.) inside the rainwater manhole 2.

The fixed body 31 is formed of a C-shaped expandable member having a notch 40 so that it can pass through the internal space 24 of the lid receiving body 8, that is, for example, an elastically deformable elastic member 41. The outer diameter of the fixed body 31, which is made only of this elastic member 41, is slightly larger than the inner diameter of the riser pipe 7 before elastic deformation. The fixed body 31 is attached to a predetermined position on the inner surface of the riser pipe 7 in a state where it is elastically deformed to the contracted diameter side so as to correspond to the inner diameter of the riser pipe 7, and is then fixed, for example, with an adhesive.

The fixed body 31 has a peripheral wall portion 42 that is fixed to the inner peripheral surface of the riser pipe 7, and an upper plate portion 43 that protrudes radially inward from the upper end of the peripheral wall portion at a downward incline and to which the elastic packing 32 is attached from above.

A plurality of rectangular recesses 45 that serve as adhesive reservoirs are formed at intervals in the circumferential direction on the outer peripheral surface of the upper portion of the peripheral wall portion 42. Each recess 45 is open at the top so that the adhesive can enter from above, and is formed from the vertical middle portion to the upper end on the outer peripheral surface of the peripheral wall portion 42. Note that, for example, although not shown, a single longitudinal recess extending in the circumferential direction may be formed on the outer peripheral surface of the upper portion of the peripheral wall portion 42.

The upper surface of the upper plate portion 43 is formed with an inclined surface 46 that is inclined at an acute angle of a predetermined inclination angle α with respect to the horizontal direction so as to gradually slope downward from the outer end side toward the inner end side. The predetermined inclination angle α is, for example, 15° to 30°, and preferably 25° (see FIG. 2).

When the elastic packing 32 is attached to the upper plate portion 43 from above, the lower attachment portion 52 of the elastic packing 32 is guided radially inward (toward the center) by the inclined surface 46 of the upper plate portion 43. In other words, the attachment portion 52 of the elastic packing 32 elastically deforms once to the reduced diameter side while being guided radially inward by the inclined surface 46, and then, when it leaves the inclined surface 46, it returns to its original shape by elastic restoring force. In this way, the inclined surface 46 with a predetermined inclination angle α makes it easier to insert the elastic packing 32 and also prevents foreign matter such as dirt from becoming lodged.

The inclined surface 46 of the fixed body 31 is parallel to the inclined surface 55 of the mounting portion 52 of the elastic packing 32, or has an inclination angle greater than that of the inclined surface 55 of the mounting portion 52, thereby improving the insertability of the elastic packing 32. In addition, the inclination angle may be changed midway along the inclined surface 46 to improve the insertability.

The elastic packing 32 has a lip-shaped contact portion 51 on the upper side that contacts the inner surface of the riser pipe 7 watertightly and airtightly all around when elastically deformed, and an attachment portion 52 on the lower side that is attached from above to the upper plate portion 43 of the fixed body 31. The maximum outer diameter of the elastic packing 32 is slightly larger than the inner diameter of the riser pipe 7 before elastic deformation.

The contact portion 51 is formed with an inverted U-shaped cross section that opens downward. The mounting portion 52 is formed with a U-shaped cross section that opens radially outward. In other words, an annular recessed groove 53 is formed on the upper outer peripheral surface of the mounting portion 52, into which the inner end side of the upper plate portion 43 of the fixed body 31 fits.

The groove 53 has a lower horizontal surface 56, an upper inclined surface 57, a vertical surface 58 connecting the upper and lower surfaces 56, 57, and a groove space 59 facing these surfaces 56, 57, 58. The upper inclined surface 57 of the groove 53 is inclined at the same angle as the inclined surface 46 of the upper plate portion 43 of the fixed body 31 so as to be in close planar contact with the inclined surface 46.

The mounting portion 52 also has an inclined, i.e., inverted truncated cone-shaped support surface 60 that receives and supports the underside of the main body portion 61 of the main body member 36 of the valved main body 33, and this support surface 60 is also inclined at the same angle as the inclined surface 46. Note that the guide surface 71 on the upper surface of the main body portion 61 is also inclined at the same angle as the inclined surface 46, but the support surface 60 and the guide surface 71 do not necessarily have to be at the same angle as the inclined surface 46, and may be inclined at a different angle. In addition, the lower part of the outer circumferential surface of the mounting portion 52 is formed in the shape of an inverted truncated cone whose diameter decreases downward.

The valved body 33 is composed of a body member 36 that can be attached from above to the inner circumferential surface of the elastic packing 32 attached to the fixed body 31, and an elastically deformable check valve 35 that is circular in plan view and held by the body member 36. The body member 36 is detachably attached to the inner circumferential surface of the elastic packing 32 so that at least a portion of the outer circumferential surface (e.g., the upwardly protruding cylindrical portion 62) is in watertight and airtight contact with the inner circumferential surface of the elastic packing 32 all around. The outer diameter of the body member 36 is slightly smaller than the minimum inner diameter of the support portion 25 of the lid receiving body 8. Therefore, the valved body 33 can pass through the internal space 24 of the lid receiving body 8.

The main body member 36 has a mortar-shaped, i.e. inverted truncated cone-shaped, main body portion 61 that tapers downward, a short cylindrical upward-protruding tube portion 62 that protrudes upward from the outer circumferential end of the upper surface of the main body portion 61, a short cylindrical downward-protruding outer tube portion 63 that protrudes downward from near the outer circumferential end of the lower surface of the main body portion 61, and a short cylindrical downward-protruding inner tube portion 64 that protrudes downward from the inner circumferential end of the lower surface of the main body portion 61.

The lower end surface of the downward-projecting inner cylinder portion 64 forms a truncated cone-shaped valve seat surface 65, to which the valve portion 83 of the check valve 35 is in close contact and detachable contact. The valve seat surface 65 has a small contact area with the valve portion 83, making it difficult for foreign matter to be caught when the valve is closed. The downward-projecting inner cylinder portion 64 has an upper opening 66 and a lower opening 67, and the lower opening 67 is opened and closed by the check valve 35.

The main body member 36 has a small annular valve holding part 68 that is positioned in the center of the main body member 36 within the downward-projecting inner cylindrical part 64 and holds the check valve 35, a large annular prevention part 69 that is positioned concentrically with the valve holding part 68 within the downward-projecting inner cylindrical part 64 and prevents the valve part 83 of the check valve 35 from rolling up, and a grip part 70 that is connected to the valve holding part 68 and the prevention part 69 and at least a part of which is located above the check valve 35. The grip part 70 that is held by the operator is stored and positioned within the main body part 61, the entirety of which is in the shape of an inverted truncated cone.

The main body 61 has a guide surface 71 on its upper surface, which is an inverted truncated cone-shaped guide that guides rainwater drained from above (and both the rainwater and foreign objects, if soil or other foreign objects flow in together with the rainwater) toward the center, which is the backflow prevention valve 35 side, that is, toward the top opening 66 of the downwardly protruding inner cylinder 64. This guide surface 71 is formed as an inverted truncated cone surface that narrows toward the backflow prevention valve 35 side, which is the lower side, and since rainwater is smoothly guided toward the backflow prevention valve 35 side located on the narrowing diameter side, the formation of rainwater pools on the guide surface 71 is suppressed.

The gripping portion 70 has three vertical plate portions 76, 77, 78, i.e., a first plate portion 76, a second plate portion 77, and a third plate portion 78, positioned at equal intervals in the circumferential direction of the main body member 36, i.e., at intervals of, for example, 120°, an annular portion 79 connecting these three plate portions 76, 77, 78, and a horizontal plate portion 80 with an arc-shaped surface that protrudes from a part of the outer circumferential end of the annular portion 79 and is positioned between the mutually opposing first plate portion 76 and second plate portion 77.

The first plate portion 76 and the second plate portion 77 are both of the same shape, but the third plate portion 78 is formed in a longitudinal shape along a different radial direction, and a triangular portion 78a of the third plate portion 78 is erected vertically on the guide surface 71 of the main body portion 61. The annular portion 79 is formed with a larger diameter than the annular valve holding portion 68, and is located above and concentric with the valve holding portion 68. The horizontal plate portion 80 is located above the check valve 35, and overlaps with part of the check valve 35 in a plan view (see FIG. 5(a)).

When gripping the gripping portion 70, the operator inserts two fingers, for example the index finger and middle finger, into the space 75 between the first plate portion 76 and the second plate portion 77 and hooks the two fingers on the underside of the horizontal plate portion (finger hook portion) 80, while pressing the thumb against the top surface of the third plate portion (finger rest portion) 78.

In this way, the operator can stably hold the valved main body 33 with one hand by using the gripping portion 70, so that the valved main body 33 can be attached and detached to and from the elastic packing 32 with only one hand without using any tools.

When attaching the valved body 33, the gripping part 70 is held in one hand, and the valved body 33 is moved downward while remaining in a horizontal position, so that it is attached to the elastic packing 32 by strongly pushing it from above to below. On the other hand, when removing the valved body 33, the gripping part 70 is held in one hand, and the wrist is rotated around the thumb as a fulcrum to change the position of the valved body 33 from a horizontal position to an inclined position, and this change lifts the part of the outer periphery of the valved body 33 opposite the thumb side and removes it from the elastic packing 32, and then the valved body 33 is moved upward while remaining in an inclined position to remove it from the elastic packing 32. In either case, the worker needs to use a certain amount of force, but it is possible to attach and remove the valved body 33 to and from the elastic packing 32 without tools while holding the gripping part 70 in one hand.

The backflow prevention valve 35 is, for example, an umbrella valve with an inverted T-shape in cross section, which allows the forward flow (downward flow) of rainwater that flows into the riser pipe 7 from the water passage hole 28 in the lid 9, but prevents the backflow (upward flow) of odors and pests in the rainwater manhole 2.

The check valve 35 is integrally formed from an elastic material such as silicone rubber, and has a disk-shaped base 81, a rod-shaped mounting portion 82 erected in the center of the base 81, and a thin-film valve portion 83 protruding radially outward from the outer periphery of the base 81.

The mounting portion 82 is fitted and inserted from below into the valve holding portion 68 of the main body member 36, so that it is attached and held in the valve holding portion 68 in a non-removable state. A bulge 84 is formed on the outer peripheral surface of the vertical middle portion of the mounting portion 82 to prevent it from falling out.

The valve portion 83 has an annular contact surface 85 on the upper surface on the outer periphery side, and this contact surface 85 normally abuts in a planar manner so as to be able to come into contact with and separate from the valve seat surface 65 of the main body member 36. When the valve portion 83 elastically deforms so as to bend downward due to the weight of rainwater (force received from above), the contact surface 85 separates from the valve seat surface 65 and the bottom opening (discharge port) 67 opens, and as a result, the rainwater is discharged downward (downstream). When the rainwater is discharged, the valve portion 83 returns to its original shape due to its elastic restoring force, and the contact surface 85 comes into contact with the valve seat surface 65, closing the bottom opening 67.

The valve portion 83 is formed in an upwardly convex arc shape so that it is not easily deformed by forces received from below (such as pressure within the sewer system). The apex 86 of this convex arc shape of the valve portion 83 is located above the valve seat surface 65 within the downwardly protruding inner cylinder portion 64. Before the mounting portion 82 is attached to the valve holding portion 68, the valve portion 83 is umbrella-shaped, i.e., inverted truncated cone-shaped. However, when the mounting portion 82 is inserted into the valve holding portion 68 and attached, the contact surface 85 comes into contact with the inclined valve seat surface 65, causing the valve portion 83 to elastically deform into an upwardly convex arc shape.

Next, the construction procedure or installation method for installing the backflow prevention device 3 to the existing rainwater catch basin 2 will be explained with reference to Figures 6 to 8.

As shown in FIG. 6(a), first, the worker removes the lid 9 from the lid receiving body 8 to open the opening 23. Then, the worker removes the dirt and other deposits 88 that are attached to the inner surface of the riser pipe 7.

Next, as shown in Figures 6(b) and (c), the leveling sheet 90, which is an elastically deformable band-shaped member, is rolled into a circle and passed through the internal space 24 of the lid receiving body 8 and attached to the inner surface of the riser pipe 7. At this time, the leveling sheet 90 is attached so that its upper end abuts against the lower end of the lid receiving body 8.

Next, as shown in FIG. 7(d), the fixed body 31 is elastically deformed to reduce its diameter so that it is smaller than the inner diameter of the support portion 25, and is passed through the internal space 24 of the lid receiving body 8 and attached to the inner surface of the riser pipe 7. At this time, the fixed body 31 is attached so that the distance L between its upper end and the lower end of the leveling sheet 90 is a predetermined distance (for example, about 50 mm).

Next, as shown in FIG. 7(e), adhesive 91 is applied to the upper side of the inner circumferential surface of the riser pipe 7, in the portion located between the leveling sheet 90 and the fixed body 31, with the adhesive 91 applied to the lower end of the leveling sheet 90 and with a width approximately equal to that of the fixed body 31.

Next, as shown in FIG. 7(f), the fixed body 31 is slid upward along the inner circumferential surface of the riser pipe 7 by a distance L until its upper end abuts against the lower end of the leveling sheet 90, and then the fixed body 31 is slid circumferentially by a predetermined angle, for example, 45°. Note that the rotation angle of the fixed body 31 may be less than 45°.

As the fixed body 31 slides, the adhesive 91 enters each recess 45 from above and spreads over the entire outer circumferential surface of the fixed body 31. After, for example, one minute or more has elapsed in this state, the adhesive 91 hardens and the fixed body 31 is firmly fixed to a predetermined position on the inner circumferential surface of the riser pipe 7. Note that, due to the presence of the leveling sheet 90, the adhesive 91 does not adhere to the portion of the inner circumferential surface of the riser pipe 7 where the elastic packing 32 is in close contact.

Next, as shown in FIG. 8(g), after removing the leveling sheet 90, the elastic packing 32 is elastically deformed by contracting its diameter so that it is smaller than the inner diameter of the support portion 25, and passed through the internal space 24 of the lid receiving body 8, and attached to the fixed body 31. At this time, the elastic packing 32 is attached so that its outer peripheral surface is in close contact with the inner peripheral surface of the riser pipe 7. In this way, the elastic packing 32 is held by the fixed body 31.

Next, as shown in FIG. 8(h), the valved body 33 having the check valve 35 is passed through the internal space 24 of the lid receiving body 8 and attached to the elastic packing 32. At this time, the worker can attach the valved body 33 to the elastic packing 32 simply by pushing the valved body 33 downward while holding the gripping portion 70 with one hand and keeping it in a horizontal position.

Next, as shown in FIG. 8(i), the lid 9 is attached to the lid receiving body 8 to close the opening 23, completing the installation of the backflow prevention device 3. In this way, the worker can easily install the backflow prevention device 3 on the inner surface of the riser pipe 7 of the existing storm water manhole 2 without using special tools.

Next, the procedure for removing the mud collection container 18 from the rainwater manhole 2 will be explained with reference to Figure 9.

When removing the mud collection container 18 with mud or other sediment 92 accumulated in the container body 19 from the rainwater catch basin 2 as shown in Figure 9 (a), the worker first removes the lid 9 from the lid receiving body 8 to open the opening 23 as shown in Figure 9 (b).

Next, as shown in FIG. 9(c), the valved body 33 having the check valve 35 is removed from the elastic packing 32, and then the valved body 33 is passed through the internal space 24 of the lid receiving body 8 and removed from inside the riser pipe 7. At this time, the worker can remove the valved body 33 from the elastic packing 32 simply by holding the gripping portion 70 with one hand and pulling the valved body 33 upward while tilting it.

Next, as shown in FIG. 9(d), the worker lifts the mud container 18 by the handle 20, and passes the mud container 18 through the fixed body 31, the elastic packing 32, and the lid receiving body 8 in that order, and removes it from the riser pipe 7.

After removing the sediment 92, the worker returns the mud container 18 to its original position and sequentially installs the valved body 33 and the lid 9. In other words, the worker performs the installation process in reverse to the removal process described above. In this way, the worker can easily clean the mud container 18 without using special tools.

The backflow prevention device 3 described above can be attached to the riser pipe 7 of the rainwater manhole 2 to appropriately prevent odors and pests that occur within the rainwater manhole 2 from leaking out to the outside of the rainwater manhole 2.

In addition, the backflow prevention device 3 can be easily attached to the riser pipe 7 without using any special tools, and the mud collection container 18 can be easily cleaned after attachment.

Furthermore, the fixed body 31 is composed of a C-shaped elastic member 41 having a notch 40, so that it can easily pass through the internal space 24 of the lid receiving body 8 and can appropriately accommodate the inner diameter of the riser pipe 7.

In addition, the fixing body 31 has a recess 45 that serves as a reservoir for the adhesive, which prevents poor adhesion and allows the fixing body 31 to be properly fixed to the riser pipe 7. Moreover, excessive excess adhesive is not produced, and adhesive dripping, etc., can be prevented.

Furthermore, the elastic packing 32 has a contact portion 51 where the outer periphery is in close contact with the inner periphery of the riser pipe 7 and the inner periphery is in close contact with the outer periphery of the main body member 36, so that a watertight and airtight state can be appropriately maintained and the elastic packing 32 can be prevented from shifting out of position.

In addition, the elastic packing 32 has a mounting portion 52 in which a groove 53 is formed on the upper part of the outer circumferential surface and the lower part of the outer circumferential surface is formed in an inverted truncated cone shape, so that the elastic packing 32 can be easily mounted to the fixed body 31.

Furthermore, the main body member 36 of the valved main body 33 has an inverted truncated cone-shaped guide surface 71 that guides and collects rainwater toward the check valve 35 located on the reduced diameter side, so that the formation of rainwater pools on the guide surface 71 can be appropriately prevented.

In addition, the main body member 36 of the valved main body 33 has a gripping portion 70 that is held by the operator, so the valved main body 33 can be easily attached to and detached from the elastic packing 32 using only one hand.

Furthermore, the check valve 35 of the valved main body 33 has a valve portion 83 that moves toward and away from the valve seat surface 65 of the main body member 36, so that incoming rainwater can be quickly discharged downward and odors and pests can be appropriately prevented from flowing back (i.e., moving upward).

Next, the second embodiment of the present invention will be described with reference to FIG. 10.

The backflow prevention device 3 shown in Figure 10 is attached to the upper end of the riser pipe 7. The fixed body 31 of this backflow prevention device 3 is composed of a short cylindrical lid receiving body (receiving seat) 8, not a C-shaped elastic member 41. In other words, this fixed body 31 also serves as the lid receiving body 8.

In addition, an annular groove 101 is formed on the inner peripheral surface of the lid receiving body 8, and an elastic packing 32 is fitted into this groove 101, and a valved body 33 is removably attached to the inner peripheral side of this elastic packing 32.

The backflow prevention device 3 shown in FIG. 10 can also provide the same effects as the first embodiment, such as being able to appropriately prevent odor leakage.

Next, the third embodiment of the present invention will be described with reference to FIG.

The backflow prevention device 3 shown in FIG. 11 is attached to the vertical middle of the riser pipe 7. The fixed body 31 of this backflow prevention device 3 is composed of a short cylindrical joint 102, not a C-shaped elastic member 41. In other words, this fixed body 31 also serves as the joint 102. In this example, the riser pipe 7 is composed of, for example, a first riser pipe 7a and a second riser pipe 7b, and these two pipes 7a, 7b are connected via the joint 102.

In addition, an annular groove 103 is formed on the inner peripheral surface of the fitting 102, and an elastic packing 32 is fitted into this groove 103, and a valved body 33 is removably attached to the inner peripheral side of this elastic packing 32.

The backflow prevention device 3 shown in FIG. 11 can also provide the same effects as the first embodiment, such as being able to appropriately prevent odor leakage.

Next, the fourth embodiment of the present invention will be described with reference to Figures 12 and 13.

The backflow prevention device 3 shown in Figures 12 and 13 is attached to the lower end of the riser pipe 7. The fixed body 31 of this backflow prevention device 3 is composed of the manhole main body 6, not a C-shaped elastic member 41. In other words, this fixed body 31 also serves as the manhole main body 6.

In addition, an annular groove 105 is formed on the inner circumferential surface of the cleaning port 13 of the manhole body 6, an elastic gasket 32 is fitted into this groove 105, and a valve-equipped body 33 is removably attached to the inner circumferential side of this elastic gasket 32 and the inner circumferential side of the cleaning port 13.

The backflow prevention device 3 shown in Figures 12 and 13 can also provide the same effects as the first embodiment, such as being able to appropriately prevent odor leakage.

In any of the above embodiments, the gripping portion 70 of the valved body 33 may have a finger rest surface 106, which is a horizontal semicircular finger rest against which the operator presses his or her thumb from above when gripping the gripping portion 70, as shown in FIG. 14. The finger rest surface 106 is connected to the tip side of the triangular portion 78a of the third plate portion 78.

The backflow prevention device is not limited to a configuration in which the mounting body is fixedly attached to the pipeline using a fixing means such as adhesive, and may be configured, for example (not shown), in which the mounting body is attached to the pipeline in an adjustable position.

Furthermore, the backflow prevention device may be configured such that the valve body is directly attached to the mounting body without using a sealing member such as an elastic packing.

In addition, the mounting body is not limited to being made of only an elastic member (one member), but may be made of multiple members so that it can be expanded and contracted, for example.

Furthermore, the backflow prevention device may be installed in, for example, a newly constructed rainwater catchment or a newly constructed pipeline, rather than in an existing rainwater catchment.

In addition, the pipeline in which the backflow prevention device is installed is not limited to a riser pipe rising from the manhole body, but can be any pipeline into which wastewater generated outdoors flows.

Although several embodiments and variations of the present invention have been described, it is possible to combine the various embodiments and variations as appropriate without departing from the spirit of the present invention.

3 Backflow prevention device 7 Rise pipe (pipe) 9 Lid
31 Fixed body that is the mounting body
32 Elastic packing, which is a sealing material
33 Valve body
35 Check valve
41 Elastic member
70 Grip
71 Guide surface that is a guide part

Claims (6)

A backflow prevention device to be attached to a pipeline including a lid through which wastewater generated outdoors flows into the pipeline , and a lid receiving part to which the lid is detachably fitted and whose inner diameter is smaller than the inner diameter of the pipeline ,
a mounting body that is made of an expandable and contractible elastic member and is attached to a portion of the pipeline below the lid;
a valved main body attached to the attachment body and having a check valve for preventing backflow of odors ;
The mounting body is elastically deformable to reduce its diameter so that its outer diameter is larger than the inner diameter of the pipeline and smaller than the inner diameter of the lid receiving portion.
A backflow prevention device characterized by: 2. The backflow prevention device according to claim 1 , wherein the valve body is detachably attached to the mounting body via a seal member. The seal member is attached to the mounting body so that the outer periphery of the seal member is in close contact with the inner periphery of the pipeline,
3. The backflow prevention device according to claim 2 , wherein the valve body is detachably attached to the inner circumferential side of the seal member. 4. The backflow prevention device according to claim 1 , wherein the valved body has an inverted truncated cone-shaped guide portion that guides drainage toward the backflow prevention valve located on the reduced diameter side. 5. The backflow prevention device according to claim 1 , wherein the valved body has a grip portion, at least a portion of which is located above the backflow prevention valve. 6. The backflow prevention device according to claim 1, wherein the valve body is removable from the pipeline.

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