| 摘要 |
A known device at roof drains for discharging through the roof drain water being collected at the roof includes a gully (1) having an inlet opening (3), the upper edge of which is placed in the plane (2) of the roof and also an outlet opening (5) which is smaller than said inlet opening (3) and is connected to a drainage pipe. A plate means (7) is arranged in the gully under the plane of the upper edge of the inlet opening (3), which plate means (7) has an area (8) which blocks the water and is concentrically placed in relation to the outlet opening (5) and has a larger projection area than the area of the outlet opening. In order to control that air is mixed in the water the gully (1) has an air flow pipe (13), which is closed in relation to the space (4) of the gully, which space is between the inlet opening (3) and the outlet opening (5) and which pipe (13) has an open end (17) to the environment above the inlet opening (3) of the gully and has a second open end in the outlet opening (5) of the gully and which flow pipe (13) has a small cross-section area in relation to the outlet opening of the gully. |
