跌水井

跌水井 Drop well energy dissipation facilities is provided with a manhole, it can overcome the huge impact of the water drop. If there is no water well, when the water pipe downhill, the flow of water is very fast, the impact of a large, long time will wash the pipe bad. The drop well is mainly used to drop the water head over the boundary of Im. The pipeline due to terrain elevation difference, fall head larger on the trunk or branch of the people buried deeper. As everyone knows In order to prevent the flow velocity of the pipeline from exceeding the scouring velocity (maximum velocity), the hydraulic condition of the pipeline is often used to improve the hydraulic condition of the pipeline. But it leads to it: 1, not laying the pipeline according to the slope of the road, then the buried depth of the pipe will be increased, the pipe diameter will increase; 2, drop wells set, so that the cost increases. But if not set, then to some large slope, into the road slope of 4.5%, it may lead to downstream of the smooth slope of the pipe diameter needs to be reduced by more than 2 times, so obviously does not meet the specifications. But in reality it is not a lot of engineering design according to the maximum velocity of control parameters to decide whether to adopt water wells drainage way. What I want to ask is..: You prawns, you generally in what grade, road width is the number of municipal roads to set down wells, on the basis of what? In general the design flow rate does not exceed 5m/s (metal tube 10) under the condition of no need to set down wells, can be considered a level for the downstream pipe diameter, the general cost in the project investment in the proportion is not large, you say 4.5% not too big, I have no problem doing 9%! Principle of setting down water wells General requirements for drop well settings: 1, when the drainage tube water head for the 1.0~2.0m, should be set down wells, water head was more than 2.0m, should be set down wells. No water well should be set at the bend of pipe. 2 、 the flow velocity in the drain is too large to be added to the adjustment. 3 、 the branch pipe is connected to the lower elevation of the dry pipe. 4, the pipeline meets the underground obstruction, must drop through. 5, when submerged discharge, in the water before the last well. Suppose the difference between two points is H1, the length of two points is L, the diameter between two points is DN, and the hydraulic gradient of the pipe diameter is S by checking the hydraulic calculation table Then, the slope gradient is L*S = H2, H1 - H2 for the drop head. Then according to the standard according to the value judgment to set down wells Acting head is at a point of water pressure, such as our taps need a certain amount of water pressure to meet our water needs, almost 2 to 5 of them, these are the role of water head Why do water wells fall? The reason is that the grade is too steep Then you have to calculate the maximum flow speed, the non-metallic pipe should be flow rate is not greater than 5M/S, in order to reduce the hydraulic erosion of the pipeline. The flow rates are different at different pipe diameters / flow rates at the same slope! It takes calculation to make sure. As far as possible not set / less set water wells, or water wells project too large, but also affect the layout of other pipelines! ------UPVC large diameter winding pipe is preferred for blowdown Material: polyvinyl chloride (PVC-U) Caliber (mm) 300mm - 2500mm Ring stiffness (Kpa = 2Kpa---4Kpa) Color: white Features: PVC-U material is lightweight: the proportion of PVC-U material is only 1/10 of cast iron, easy to transport and easy to install and lower cost. Excellent chemical resistance: PVC -U has excellent acid and alkali resistance, except for near saturation point, strong acid base or strong Oxidising, agents, atmaximun. Non conductive: PVC -U material can not conduct electricity, nor by electrolysis, current corrosion, there should be no need for two processing. No burning, no combustion, no fire care, low prices, the use of UPVC glue connection, practice proved reliable, safe, easy to operate, durable, good resistance to climate, and can not be corrupted by bacteria and fungi. Resistance is small, flow rate is high: the inner wall is smooth, the fluid flow property is little, the dirt is not easy to adhere to the smooth pipe wall, the maintenance is simpler, and the maintenance cost is low. Use: 1, apartments, residential, garden and other urban water and rainwater, factory sewage, waste pipe; 2 underground conduit and communication cable duct; 3, farmland irrigation pipeline; 4. Sea water pipeline; 5, other low pressure water supply, drainage and so on. First of all, determine the slope of the ground and determine the slope of the pipeline, not greater than the ground Secondly, the slope is determined by flow rate, the metal pipe is 10m/s, and the nonmetal pipe is 5m/s. Finally, after the above method has been used, it still can not reach the high difference, so you can consider setting a gentle slope for 1.2 meters of inspection wells (H<=1.2 called inspection wells, H>=1.2 is called down wells). If not, there are only two ways, either to set down a well or to change the direction of the pipeline. 168 distance, more than 20 meters height difference, this kind of slope, general road will not have. In reality should be relatively rare, such as flow can be adjusted, it is recommended that you reduce the pipe diameter, increase the pipe slope. The slope is too large, the pipe erosion is too large, the specifications require a maximum slope of 15%, the design is best not to use, the flow rate is too large, the downstream inspection well, When the degree of fullness is high, it is easy to take water, turning and turning slope will also have problems. It is suggested to adopt a drop well and a place in place. 1. increase the slope (control the maximum flow rate) + more down wells 2., increase the slope (control the maximum flow speed) + a ladder type drop well 3. normal slope + a ladder down water well Drainage piping shall be controlled at the ground elevation of the starting point, or at the bottom elevation of the inspection well at the starting point. Then determine the slope and location of the inspection well (mainly considering the access point), according to the flow rate of the pipe load, with the maximum (or minimum) fullness, maximum (or minimum) flow speed, and whether the approved slope meets the requirements. If the demand is not satisfied, the corresponding measures of energy dissipation (or energy gain) must be taken.