Abstract: Provided is a blower installed at a manhole opening, with which it is possible to facilitate an entry or an exit of a worker or an import or an export of an article. The present invention provides a ventilation system comprising a frame and a single or a plurality of airflow generation means arranged at the frame, a direction of an airflow is adjusted so that the airflow generated from the airflow generation means flows along with a virtual axis penetrating a virtual surface which the frame is regarded as to periphery, and the airflow flows while swallowing up the surrounding air of the virtual axis, and an air volume more than two times of total fluid volume of the airflow is generated.

Abstract: An opening/closing device according to the present invention includes a gate, a fall prevention unit, a support release unit, a first float, a floating prevention unit, a second float, and a floating prevention release unit. The gate receives a flow of fluid, and is able to fall down toward a downstream direction of the flow. The fall prevention unit supports the gate, thereby preventing the gate from falling down. The support release unit releases the support for the gate by the fall prevention unit. The first float is arranged on an upstream side of the gate, is arranged on one of the left side and the right side of the gate viewed from upstream, and is less in the specific gravity than the fluid. The floating prevention unit prevents the first float from floating.

Abstract: An opening/closing device according to the present invention includes a gate, a fall prevention unit, a support release unit, a first float, a floating prevention unit, a second float, and a floating prevention release unit. The gate receives a flow of fluid, and is able to fall down toward a downstream direction of the flow. The fall prevention unit supports the gate, thereby preventing the gate from falling down. The support release unit releases the support for the gate by the fall prevention unit. The first float is arranged on an upstream side of the gate, is arranged on one of the left side and the right side of the gate viewed from upstream, and is less in the specific gravity than the fluid. The floating prevention unit prevents the first float from floating.

Abstract: Provided is a blower installed at a manhole opening, with which it is possible to facilitate an entry or an exit of a worker or an import or an export of an article. The present invention provides a ventilation system comprising a frame and a single or a plurality of airflow generation means arranged at the frame, a direction of an airflow is adjusted so that the airflow generated from the airflow generation means flows along with a virtual axis penetrating a virtual surface which the frame is regarded as to periphery, and the airflow flows while swallowing up the surrounding air of the virtual axis, and an air volume more than two times of total fluid volume of the airflow is generated.

Abstract: A control plate is provided at a preferred position in a storm overflow chamber. An inflow pipe, an intercepting pipe, and an outflow pipe are connected to the storm overflow chamber. A vortex flow type water surface control device for a draining device includes the overflow chamber, and a control plate arranged in front of an opening portion of the intercepting pipe opening to the storm overflow chamber. A relation (1) 0.5 D?X?0.7 D and 0.83 D?Y?1.5 D holds true, or a relation (2) 0.4 D?X?0.5 D and 1.0 D?Y?1.5 D holds true, where D represents an inner diameter of the opening portion, X represents a projection length of the control plate with respect to the opening portion, and Y represents a distance between the control plate and the opening portion. As a result, contaminants enter the intercepting pipe.

Abstract: A wastewater treatment apparatus includes an air diffusing unit, a denitrification confirming unit, a nitrification confirming unit, a gas supply-amount control unit. The air diffusing unit supplies gas to nitrogen-containing water. The denitrification confirming unit provided at a first predetermined position confirms a denitrification state whether a desired proportion of the nitrate has been denitrified. The nitrification confirming unit provided at a second predetermined position confirms a nitrification state whether a desired proportion of the ammonia has been nitrified. The gas supply-amount control unit controls a gas supply amount at least on an upstream side of the denitrification confirming unit, so that the desired proportion of the nitrate is denitrified at the first predetermined position, and controls the gas supply amount at least on an upstream side of the nitrification confirming unit, so that the desired proportion of the ammonia is nitrified at the second predetermined position.

Abstract: In a conventional storm overflow chamber of a combined sewer system, inflowing floating debris do not flow into an intercepting pipe in a rainy weather, and flow out to a public water body, causing a water pollution in the public water body. According to a vortex flow type water surface control device for a draining device of the present invention, a control plate (6) higher than at least a separating weir (1) is provided between an opening of an inflow pipe (2) and an opening of an intercepting pipe (3) in a storm overflow chamber of a combined sewer system. Moreover, a guide wall (7) higher than at least the separating weir (1) is provided along the separating weir between the opening of the inflow pipe (2) and the separating weir (1).

Abstract: There is provided is a blower installed at a manhole opening, with which it is possible to facilitate an entry or an exit of a worker or an import or an export of an article. The present invention provides a ventilation system in a pipe conduit using the blower. Provided is a blower comprising: a ring-like or circular arc-like frame; a nozzle installed continuously or discontinuously along the frame; and compressed air supplying means for supplying the nozzle with compressed air, wherein the compressed air supplied from the compressed air supplying means is emitted while swallowing up air in the nozzle or near the nozzle, whereby, an airflow to a normal direction of a disk surface of which the flame is periphery is generated. The nozzle may be a nozzle for exhausting an air flown from an entry port of a cylindrical flow channel to an exit port of the cylindrical flow channel, and a plurality of the nozzles may be discontinuously installed along the frame.

Abstract: An opening/closing device 1 according to the present invention includes a gate 10 that receives a flow of a sewage W in an upright state, and can fall toward a downstream side of the flow and a first spring 52a that generates a force for bringing the gate 10 into an upright state, wherein the first spring 52 generates a force insufficient for bringing the gate 10 into the upright state if the gate 10 is in a fallen state, and generates a force sufficient for bringing the gate into the upright state if the gate 10 is tilted by an angle equal to or less than a predetermined angle.

Abstract: An opening/closing device includes a gate that receives a flow of a sewage, and can fall toward a downstream side of the flow, a fall prevention unit that prevents the gate from falling by supporting the gate, a support release unit that releases the support for the gate by the fall prevention unit, a first float that is arranged on the upstream side of the gate, and is smaller in specific gravity than the sewage, a surfacing prevention unit that prevents the first float from surfacing, a second float that is arranged on the upstream side of the gate, above the first float, and is smaller in specific gravity than the fluid, and a surfacing-prevention release unit that releases, resulting from surfacing of the second float, the prevention of the surfacing of the first float by the surfacing prevention unit. Further, the support release unit is activated resulting from surfacing of the first float.

Abstract: A control plate is provided at a preferred position in a storm overflow chamber. An inflow pipe, an intercepting pipe, and an outflow pipe are connected to the storm overflow chamber. A vortex flow type water surface control device for a draining device includes the overflow chamber, and a control plate arranged in front of an opening portion of the intercepting pipe opening to the storm overflow chamber. A relation (1) 0.5D?X?0.7D and 0.83D?Y?1.5D holds true, or a relation (2) 0.4D?X?0.5D and 1.0D?Y?1.5D holds true, where D represents an inner diameter of the opening portion, X represents a projection length of the control plate with respect to the opening portion, and Y represents a distance between the control plate and the opening portion. As a result, contaminants enter the intercepting pipe.

Abstract: An opening/closing device includes a gate that receives a flow of a sewage, and can fall toward a downstream side of the flow, a fall prevention unit that prevents the gate from falling by supporting the gate, a support release unit that releases the support for the gate by the fall prevention unit, a first float that is arranged on the upstream side of the gate, and is smaller in specific gravity than the sewage, a surfacing prevention unit that prevents the first float from surfacing, a second float that is arranged on the upstream side of the gate, above the first float, and is smaller in specific gravity than the fluid, and a surfacing-prevention release unit that releases, resulting from surfacing of the second float, the prevention of the surfacing of the first float by the surfacing prevention unit. Further, the support release unit is activated resulting from surfacing of the first float.

Abstract: An opening/closing device 1 according to the present invention includes a gate 10 that receives a flow of a sewage W in an upright state, and can fall toward a downstream side of the flow and a first spring 52a that generates a force for bringing the gate 10 into an upright state, wherein the first spring 52 generates a force insufficient for bringing the gate 10 into the upright state if the gate 10 is in a fallen state, and generates a force sufficient for bringing the gate into the upright state if the gate 10 is tilted by an angle equal to or less than a predetermined angle.

Abstract: A vortex flow type water surface control device for a draining device is provided. The vortex flow type water surface control device may include an inflow pipe, an outflow pipe, an intercepting pipe, and a separating weir that is disposed to block the intercepting pipe and the inflow pipe from the outflow pipe. The vortex flow type water surface control device may also include a control plate that is disposed between an opening of the inflow pipe and an opening of the intercepting pipe. A height of the control plate may be higher than at least a height of the separating weir. The control plate may be apart from the separating weir, and may approximately extend to a center axis of the intercepting pipe.

Abstract: In a conventional storm overflow chamber of a combined sewer system, inflowing floating debris do not flow into an intercepting pipe in a rainy weather, and flow out to a public water body, causing a water pollution in the public water body. According to a vortex flow type water surface control device for a draining device of the present invention, a control plate (6) higher than at least a separating weir (1) is provided between an opening of an inflow pipe (2) and an opening of an intercepting pipe (3) in a storm overflow chamber of a combined sewer system. Moreover, a guide wall (7) higher than at least the separating weir (1) is provided along the separating weir between the opening of the inflow pipe (2) and the separating weir (1).

Abstract: A shield tunneling machine has a shield body and a cutter head rotatably provided at the forward end of the shield body in the excavation direction. Abrasive jet spray nozzles for spraying abrasive jet water are movably provided on the cutter head. Obstacles encountered during excavation can be broken efficiently with high cutting quality by properly controlling the movable abrasive jet spray nozzles according to the size and configuration of each particular obstacle.