Thread Content
Internal layout and structural features of rainwater pumping stations! In rainwater pumping stations, the pumps are generally arranged in a single row; each pump draws water from its own collection tank and discharges it independently into the outlet well. The outlet well is usually placed outdoors; when overflow may occur, it should be sealed, and a vent pipe should be installed on the well cover or an overflow pipe should be placed within the outlet well to direct the backflowing water back into the collection tank. The distance between the water intake and the bottom of the collection tank is generally best at D/2 (where D is the diameter of the water intake); when this distance increases to D, the pump efficiency decreases instead. If this distance must be greater than D, to improve the hydraulic conditions, an eddy current prevention wall (check valve) should be installed below the water intake. The distance between the water intake and the pool wall should not exceed D/2; if the collection tank can ensure a uniform distribution of water flow, the distance between the suction nozzles of each pump should be 2D. Since the head of an axial flow pump is very low, the pressure pipe should be as short as possible to minimize head losses. The diameter of the pressure pipe should be chosen so that the velocity head in it is less than 4%–5% of the pump’s head. No gate valve is installed at the outlet of the pressure water pipe; only a flap valve is used. The highest water level in the collection tank is generally at the elevation of the top of the inlet main pipe, while the lowest water level is usually slightly below the bottom of that same main pipe. For pump stations with high flow rates, in order to avoid overly deep pump houses that would make construction difficult, it is also possible to locate them slightly above the bottom of the inlet canal, so that the lowest water level is at the same elevation as the water surface in the inlet canal at that pump flow rate. The submersion depth of the pump is adopted in accordance with the specifications in the pump manual. When the length of the pump drive shaft is greater than 1.8M, an intermediate bearing must be installed. A sump pit and a small pump should be installed in the pump room to drain water that seeps from the pumps, and this pump should be placed in a location that will not be flooded. The clear distance between the foundations of adjacent units shall meet the same requirements as those for the feed water pump station. In pumping stations equipped with vertical axial flow pumps, the motor room is generally located above the pump room. Lifting equipment should be installed between the electric motors; when the span of the building is not large, a single-girder crane can be used ； When the span is large or the weight is heavy, a bridge crane should be used. Holes for lifting should be provided on the floor between the motors, and these holes are covered with covers in normal times. When using a single-girder crane, to facilitate lifting operations, the I-beam should be placed above the unit. If the beam is exactly at the center of the gate, the I-beam can be extended more than 1 meter outside the gate; after the equipment is lifted, the rear shell can be directly installed on the vehicle, which saves labor and makes transportation easier. However, attention must be paid to the issue of loads applied above. The clear height between motors should be no less than 35 m when the motor power is 55 KW or less ； For capacities above 100KW, it should be no less than 5.0m. To protect the pump, a grille should be installed in front of the collection tank. A separate ceiling can be installed for the grid. A cover plate can also be installed on top of the well, attached inside the pump station, but it must be completely separated from the machine room, transformer room, and other rooms. To facilitate the removal of the grid, a grid platform should be provided; this platform must be 0.5 m above the highest water level in the collection tank, and its width should be at least 1.2 m. Weeping holes should be provided on the platform, along with a tap for flushing. The grid width must not be less than twice the width of the inlet channel. The gap between the grating bars should be chosen based on the size of the debris that the selected water pump is able to handle; generally, 50–100 mm is a suitable value. The flow velocity within the channel ahead of the grid should not be less than 0.9 m/s, while the flow velocity passing through the grid is 0.8–1.0 m/s. Both the motor room and the water tank room are naturally ventilated, while the pump room is ventilated through ventilation ducts. An overflow pipe and a vent pipe are installed in the water outlet well. Experts in wear-resistant repair, Luoyang Napute New Materials Technology Co., Ltd. 13603889856 0379-60679266