JPH072702Y2 - Invert - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an invert provided at the bottom of a manhole, and more particularly to an invert made of a material different from concrete constituting the bottom of the manhole.

(Prior Art) Conventionally, rainwater and wastewater such as domestic wastewater and industrial wastewater have been drained into rivers without being separated. However, pollution of rivers due to sewage has become a problem, and now rainwater and sewage are separated, and rainwater is drained directly to rivers, and sewage is
Once treated at the treatment plant, it is drained to rivers. The sewage pipe through which sewage flows has a manhole (called a collecting basin or a sewage basin) installed along the way for maintenance such as cleaning and inspection. If the bottom of the manhole is flat, sewage accumulates in the manhole, causing an offensive odor. For this reason, a water passage called an invert is provided at the bottom of the manhole.

The invert is conventionally provided by scraping off the concrete that forms the bottom of the manhole. However, when concrete is scraped off and an invert is provided, the flow part must be finished in a flat state so that sewage can flow well. However, it takes a long time even for a skilled person to finish-process the flow passage portion in this way, which is very troublesome.

In order to solve such a problem, for example, Jikho Sho 56-219.
No. 08 and Japanese Utility Model Laid-Open No. 56-64482 disclose an invert made of a material different from that of the concrete forming the bottom of the manhole, for example, an invert made of synthetic resin. Such an invert can be integrated with concrete by pouring the concrete and hardening the concrete if it is temporarily fixed in a predetermined state when pouring the concrete to form the bottom of the manhole. .

(Problems to be solved by the invention) As described above, in an invert made of a synthetic resin or a metal different from that of concrete, if the concrete is placed at the bottom of the manhole, the invert may rise due to the buoyancy of the concrete. . Since the invert has a concave cross-section so that sewage can flow inside, the buoyancy applied to the invert is large with respect to its weight, and there is a high possibility that the invert will float on the concrete. If the invert floats on the concrete,
There is a risk that the sewage flowing into the manhole will not be able to flow smoothly in the specified direction due to changes in the slope of the invert.

The present invention solves the above-mentioned conventional problems, and an object thereof is to prevent the floating of the manhole bottom even when the manhole bottom is made of concrete. It is to provide an invert that can be integrated with the concrete in a predetermined state.

(Means for Solving the Problem) The invert of the present invention is arranged at the bottom of the manhole,
An invert that connects a pair of sewer pipes connected to the manhole, is fitted into a gutter-shaped main body having a concave cross-section, and the back surface of the main body, and the bottom surface is in a substantially horizontal state, And a hollow leg portion having an opening portion opened to each side in the width direction of the main body portion, whereby the above object is achieved.

(Embodiment) An embodiment of the present invention will be described below.

As shown in FIG. 2, the invert of the present invention is a manhole in which the ends of a pair of sewer pipes 20 and 20 are connected.
It is provided on a concrete bottom 31 of 30. The invert 10 has a predetermined slope so that the sewage flowing into the manhole 30 from one sewer pipe 20 flows into the other sewer pipe 20.

The invert 10 is made of synthetic resin or metal,
As shown in FIGS. 1 and 3, the gutter-shaped main body 11 having a semicircular cross section and the main body 11 are integrally formed on the back surface of the main body 11 with a predetermined space in the longitudinal direction. And has, for example, three legs 12, 12, 12.

The main body portion 11 has flange portions 11a and 11a extending laterally at the upper side edges.

Each leg 12 is a hollow body fitted over the entire circumference of the back surface of the main body 11, and each leg 12 is formed between the side edges of the flange 11a provided on each side in the width direction of the main body 11. It is provided over. The bottom of each leg 12 is in a substantially horizontal state at a position slightly below the bottom surface of the main body 11, and each flange 11
Below the side edges of a, openings 12a that are open toward the lateral direction of the main body 11 are provided.

The invert 10 of the present invention having such a configuration is a manhole.
It is installed when forming 30 concrete bottoms 31.
First, the invert 10 is arranged in the manhole 30 in a state in which the ends of the pair of sewer pipes 20 and 20 connected to the manhole 30 are connected to each other and at a predetermined gradient, and is temporarily fixed. It In such a state, the concrete forming the bottom portion 31 of the manhole 30 is placed in the lower portion of the manhole 30. The concrete poured into the manhole 30 flows into each leg 12 through the opening 12a of the leg 12 in the invert 10. The concrete that flows into each leg 12 becomes a weight and prevents the invert 10 from floating due to buoyancy. In addition, each leg portion 12 exerts the effect of a reinforcing rib that prevents the body portion 11 from being deformed by the surrounding concrete that has been cast. When the concrete is hardened in such a state, the invert 10 is firmly fixed to the concrete in a predetermined state with respect to the cast concrete.

Inverting 10 in the bottom 31 of the manhole 30 in this way
With the above arrangement, the sewage flowing into the manhole 30 from the one sewer pipe 20 passes through the inside of the main body portion 11 of the invert 10 and is introduced into the other sewer pipe 20.

(Effect of the Invention) Since the invert of the present invention has the hollow leg portion on the back surface of the gutter-shaped main body portion as described above, the invert member is placed inside the leg portion at the time of placing concrete when installing the invert into the manhole. When the concrete flows in, the invert does not float up due to buoyancy and is firmly fixed to the placed concrete. Moreover, each leg also acts as a reinforcing rib, and there is no risk of the main body deforming during concrete pouring.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of the invert of the present invention, and FIG.
The figure is a perspective view of the manhole in which the invert is installed.
FIG. 3 is a sectional view of the essential part of the bottom of the manhole. 10 …… Invert, 11 …… Main body, 11a …… Flange, 12…
… Legs, 12a …… Opening, 20 …… Sewer, 30 …… Manhole.

Claims (1)

[Scope of utility model registration request] 1. An invert which is disposed at the bottom of a manhole and connects a pair of sewer pipes connected to the manhole, and which is fitted with a gutter-shaped main body having a concave cross section and a back surface of the main body. And the bottom surface is substantially horizontal, and the hollow leg portion has an opening portion that is open toward each side in the width direction of the main body portion.