non-return valve

Abstract

To provide a check valve which can be easily attached to the water outlet of a drain pipe, the lid of which opens with the pressure of water flowing out of the drain pipe, and the lid of which is securely closed with the pressure of water from the outside. [Solution] The check valve 18 comprises a cylindrical portion 20 with an outer shape that fits tightly against the inner surface of the drain pipe 12, an upward-facing oval opening 22 created by cutting the cylindrical portion 20 along a cut surface that has an inclination angle of 60 degrees or more but less than 70 degrees relative to the central axis of the cylindrical portion 20, a lid 24 shaped to close the opening 22, a bearing 28 that receives a support shaft 26 of the lid 24 and enables the lid 24 to open and close, and an elastic packing 30 attached to the surface of the lid 24 that comes into contact with the opening 22. The lid 24 is opened by the pressure of water overflowing through the opening 22, and the water pressure of water accumulated in the drain culvert 16 presses the lid 24 against the opening 22, closing it.

Description

[Technical Field]

[0001] This invention relates to a check valve for a drain pipe. [Background technology]

[0002] An example of a check valve for preventing backflow in a drain pipe is introduced (Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-189811 [Patent Document 1] Utility Model Registration No. 3177003 Summary of the Invention [Problem to be solved by the invention]

[0004] The existing check valves are relatively complex in structure and cannot be permanently attached to the drainage pipe outlet. This invention provides a check valve that can be attached to the drainage pipe outlet to allow drainage to flow at all times and reliably prevent backflow. [Means for solving the problem]

[0005] The following configuration is a means for solving the above problems. <Configuration 1> It is attached to the outlet of one of the drainage pipes of a drainage culvert in which the outlets of multiple drainage pipes are open, A cylindrical portion having an outer shape that fits tightly against the inner surface of any drainage pipe, and an upward-facing elliptical opening created by cutting the cylindrical portion with a cutting plane having an inclination angle of 60 degrees to 70 degrees with respect to the central axis of the cylindrical portion; A lid shaped to close the opening, a bearing fixed to the outer wall of the cylindrical portion near the upper end of the opening and adapted to receive the support shaft of the lid, thereby enabling the lid to be opened and closed; and an elastic packing attached to a surface of the lid that contacts the oval opening, A check valve characterized in that the lid is opened by the pressure of water flowing through the above-mentioned opening, and the underwater weight of the lid is selected so that the water pressure of the water accumulated in the drainage culvert presses the lid against the opening, closing it. [Effects of the Invention]

[0006] It can be easily attached to the water outlet of a drain pipe, and the lid opens with the pressure of water flowing out of the drain pipe, and the lid closes securely with the pressure of water from outside. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a perspective view showing a specific example of a check valve of the present invention and a perspective view of a drainage culvert to which the check valve is attached. [Figure 2] (a) is a side view of the check valve in its normal state, (b) is a top view of the cylindrical part, and (c) is a side view of the check valve in its state of preventing backflow. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, the embodiments of the present invention will be described in detail with reference to the examples. [Example]

[0009] In Figure 1, drainage culvert 16 has outlets 14 for drainage pipes 12 and 13 at multiple locations (two locations in this example). Under normal circumstances, wastewater from each of drainage pipes 12 and 13 flows into drainage culvert 16 at its own timing. Now, let's assume that a large amount of rain flows into drainage culvert 16 from one of the drainage pipes 13.

[0010] In this case, the water level in the drain culvert 16 increases, and the drain surface 17 may rise above the height of the outlet 14 of the other drain pipe 12. In this case, the wastewater accumulated in the drain culvert 16 flows into the outlet 14 of the drain pipe 12, causing a backflow.

[0011] The check valve 18 of the present invention reliably prevents backflow with a simple structure, while maintaining the drainage function of the drain pipe at all times. This check valve 18 is installed at the outlet 14 of the drain pipe 12 where backflow of wastewater needs to be prevented.

[0012] As shown in Figure 1, this check valve 18 comprises a cylindrical portion 20 and a lid 24. The cylindrical portion 20 has an outer shape that fits tightly against the inner surface of the drain pipe 12. It is preferable that there is enough clearance so that the cylindrical portion 20 can be firmly fixed by inserting it firmly. However, a hose band (not shown) or the like may be used to securely fix the cylindrical portion 20 to the drain pipe 12.

[0013] A bearing 28 is fixed to the outer wall of the cylindrical portion 20 near the upper end of the water outlet 14. The lid 24 is supported on the bearing 28 via a support shaft 26, and the oval opening 22 can be opened and closed by moving the lid 24 up and down. The lid 24, support shaft 26, and bearing 28 should all be made of anti-corrosion treated metal or resin material to prevent corrosion by sewage.

[0014] An elastic packing 30 is attached to the surface of the lid 24 that contacts the oval opening 22. The cylindrical portion 20 is preferably a resin pipe that is widely used as a water pipe or a sewer pipe.

[0015] As shown in Figure 2(b), the cylindrical portion 20 is cut at a cut surface inclined at an angle of 60 degrees or more but less than 70 degrees with respect to the central axis 34 of the cylindrical portion 20, and an elliptical opening 22 facing upward is provided. The lid 24 is opened by the pressure of water flowing through the opening 22, which is the state shown in Figure 2(a). On the other hand, when a large amount of wastewater accumulates in the drainage culvert 16, the water pressure of the accumulated water presses the lid 24 against the opening, closing it, which is the state shown in Figure 2(c).

[0016] If the lid 24 operates in this manner, the check valve 18 will function normally. It has been found that not only the weight of the lid 24 in water but also the inclination angle α of the cut surface of the elliptical opening 22 plays a significant role in this. In known check valves, this angle α is set to approximately 90 degrees. However, various experimental results by the present inventors have shown that the optimal angle is 65 degrees.

[0017] A lid that weighs too much underwater will remain blocking the drain pipe opening. A lid that is too light will open wide due to buoyancy, and will not be able to close the opening due to water pressure. Resin is the most suitable material for the lid. When using a resin lid, it has been found that the optimal way to ensure that the lid opens due to the pressure of the water flowing out of the drain pipe and closes due to the pressure of external water is to cut the cylindrical portion 20 at a cutting surface that has an inclination angle of 60 degrees or more but less than 70 degrees with respect to the central axis 34 of the cylindrical portion 20, creating an upward-facing oval opening 22.

[0018] Even taking into account margin of error, a practical range is about 65 degrees plus or minus 5 degrees. The cushioning effect of the packing 30 presses the lid against the oval opening 22 with water pressure, reliably preventing backflow. [Explanation of symbols]

[0019] 12 Drain pipe 14 Water outlet 16 Culvert 18 Check valve 20 Cylindrical part 22 Oval opening 24 Lid 26 Spindle 28 Bearings 30 Packing

Claims

[Claim 1] It is attached to the outlet of one of the drainage pipes of a drainage culvert in which the outlets of multiple drainage pipes are open, A cylindrical portion having an outer shape that fits tightly against the inner surface of any drainage pipe, and an upwardly facing elliptical opening created by cutting the cylindrical portion with a cutting plane having an inclination angle of 60 degrees to 70 degrees with respect to the central axis of the cylindrical portion; A lid shaped to close the opening, a bearing fixed to the outer wall of the cylindrical portion near the upper end of the opening and adapted to receive the support shaft of the lid, thereby enabling the lid to be opened and closed; and an elastic packing attached to a surface of the lid that contacts the oval opening, A check valve characterized in that the lid is opened by the pressure of water flowing through the above-mentioned opening, and the underwater weight of the lid is selected so that the water pressure of the water accumulated in the drainage culvert presses the lid against the opening, closing it.

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