Have sufficient strength and certain rigidity; The inner wall surface of the pipe is smooth, reducing the flow resistance; Have certain corrosion resistance; Sufficient airtightness; Easy to process and economical.
(1) Concrete pipes and reinforced concrete pipes have high strength and convenient materials; Poor acid and alkali resistance and impermeability, many joints, heavy weight, easy to be damaged during transportation. It is applicable to sections with poor soil quality, crossing railways and roads. Nozzle type: socket, plain, tongue and groove.
(2) After the ceramic pipe is glazed, the pipe wall is smooth, impermeable and corrosion resistant; Fragile and low strength. It is applicable to the removal of acidic industrial wastewater or corrosive groundwater. Nozzle type: socket and plain.
(3) Metal tube High strength, impermeability, smooth pipe wall and few interfaces; High price and easy corrosion. It is applicable to sections with high seismic level, high groundwater level, high pressure, severe quicksand or high leakage requirements. Nozzle type: flange, socket n Common pipes: steel pipe, cast iron pipe.
(4) Plastic pipes are easy to construct, light in material and smooth in inner wall; Low strength, poor rigidity, large thermal expansion and cold contraction, easy aging under sunshine. Nozzle connection: bonding and electrofusion welding. Common pipes: UPVC rigid PVC, PE polyethylene, PP polypropylene.
(5) New pipe nHDPE high density polyethylene, FRP, glass fiber concrete, etc
3. Water supply pipe fittings
① Fitting n is used at bends, branches, reducers of pipes and at connections with other equipment, such as tees, crosses, elbows, reducers (reducers), short pipes (adapters), etc.
② Accessory water transmission and distribution control check valve: control the flow in one direction to prevent backflow Exhaust valve: rib the gas in the pipeline to reduce the flow resistance Drain valve: empty the pipeline, remove sediment Fire hydrant: fire truck water intake facilities
2、 Pipeline construction
Including: foundation, foundation and pipe socket
① Sand foundation arc plain soil foundation and sand cushion foundation are suitable for areas with very good soil conditions and no underground water. The pipeline with diameter less than 600mm and the thickness of pipe top covering soil between 0.7-2.0m, secondary pipeline and temporary pipeline not under the roadway.
② Concrete sleeper base
The concrete cushion block set under the pipe interface is applicable to the area with good soil conditions and no groundwater, and the water supply and drainage branch pipe.
③ The concrete strip foundation is paved with strip cement concrete along the whole length of the pipeline, which is suitable for all kinds of soil, especially for poor soil conditions, seismic regions, important pipelines, etc. According to the form of pipe socket, there are four types of pipe socket foundations: 90 °, 135 °, 180 ° and 360 °, which are selected according to the buried depth of the pipeline.
2、 Auxiliary structures of drainage pipeline
(1) Inspection well function: convenient for pipe connection, regular inspection and dredging. Location: pipeline intersection, turning, size or slope change, water drop, and straight line segment separated by a certain distance. Structure: composed of well bottom, well body and well cover.
The bottom of the well is generally made of low-grade concrete, and the foundation is made of crushed stone, pebble or concrete; The launder should be set and the bottom of the launder should have a certain slope to reduce the flow resistance and prevent sedimentation; The width from both sides of the launder to the well wall shall be no less than 20cm, so that the maintenance personnel can stand on the trench shoulder when they go down the well.
The shaft is built with bricks and stones, or cast-in-situ reinforced concrete. Shallow manhole that does not need to be lowered into the well, and the well bore is straight cylindrical; The well body that needs to be lowered into the well is structurally divided into three parts: well chamber, tapered part and wellbore. The chamber diameter is not less than 1m, and the shaft diameter is not less than 0.7m. The well chamber is connected with the shaft by a tapered part. Reinforced concrete cover plate can also be added on the well chamber, and the shaft can be built on the cover plate.
The well cover is composed of the well cover and the cover seat, usually made of cast iron, reinforced concrete, etc. To prevent rainwater from flowing in, the roof should be slightly higher than the ground.
(2) Function of gutter inlet: collect rainwater from surface runoff and lead it into rainwater pipeline. Location: road intersection, certain distance (25-50m) on the straight line, curb low-lying land. Structure: composed of foundation, grate, shaft and connecting pipe.
3、 Ancillary structures of water supply pipeline
(1) Function of valve well: install various water supply pipeline accessories to facilitate operation and maintenance.
(2) Function of drain valve well: drain the water discharged by the drain valve, which is composed of wet well and valve well.
（ 3) Buttress Function: to prevent the socket connector of the pipeline from falling off due to excessive water flow thrust. Location: elbow, tee, reducer, etc.
