How to use flexible waterproof casing at low temperature

How to use flexible waterproof casing at low temperature
When using low-temperature waterproof casing in cold areas, the waterproof casing should be sealed as much as possible. When waterproof casing is used in low temperature pipeline, it can ensure the pressure inside the pipeline and prevent the pipeline from freezing. Generally underground pipeline laying, waterproof casing will occur in winter. Local condensation phenomenon needs to loosen the pressure plate bolt of waterproof casing to avoid the rupture of the expansion pipeline. City water supply, drainage, heating, gas supply pipelines and long-distance oil and gas pipelines are mostly laid underground, and most of the process pipelines in factories are laid on the ground for easy operation and maintenance. The smooth flow, support, slope and drainage, compensation, insulation and heating, anti-corrosion and cleaning, marking, painting and safety of pipelines, whether laid above ground or underground, are important issues.
 
General surface pipelines should try to avoid intersections with roads, railroads and waterways. When the intersection can not be avoided, the height of the intersection span should also be able to make pedestrians, cars and boats safe passage. Underground pipelines are generally laid along roads, and appropriate distances are maintained between various pipelines to facilitate installation and maintenance. Heating pipeline surface with insulation layer, laid in the trench or protection pipe. It should be prevented from being crushed by soil while the pipe swells and moves, and planting waterproof sleeves inside these pipes is the best choice. The pipe may be subjected to a variety of external forces, including self-weight, fluid acting on the end of the pipe thrust, wind and snow loads, earth pressure, thermal stress caused by thermal expansion and contraction, vibration loads, earthquakes and other disasters. In order to ensure the strength and stiffness of the pipe, various supports (hangers) must be set, such as mobile supports, fixed supports, guide supports, spring supports, etc.. The setting of the support is determined according to the diameter, material, wall thickness and load of the pipeline and other conditions. Fixed supports are used to control the thermal elongation of the pipe in sections, so that the expansion joint works evenly; guide supports make the pipe move only axially. In order to exclude condensate, steam and other gases containing water pipeline should have a certain slope, generally not less than two thousandths. Underground drainage pipeline using gravity flow, the slope should not be less than 5/1000. steam or other water-containing gas pipeline at low places with a drain or water storage bend, some gas pipelines are also equipped with a gas-water separator, timely drainage, to prevent water hammer, impede the flow of gas in the pipe. Water supply or other liquid pipelines are equipped with exhaust devices at high places to exclude air or other gases accumulated in the pipeline to prevent abnormal operation caused by air resistance. The waterproof sleeve is made of ductile iron, which is relatively cold resistant. It can be used normally when used under normal low temperature conditions.