1 Characteristics of Steam Directly Buried Pipeline In a centralized heat supply project, production process heat consumers usually need to supply steam. In addition. For users who need to achieve both winter heating and summer thermal cooling, the use of steam as a heat medium will also have greater advantages. In recent years. With North China. Economic development in East China and Northwest China. Some centralized heating projects. Usually connected to the production process user. As well as users who want both winter heating and summer cooling, steam is the only heat medium available. At the same time, as other underground municipal facilities impose restrictions on the installation space of thermal grids, direct burial laying has also become a method of laying steam heating nets. However, due to the higher steam temperatures, the mechanical properties of the buried steam pipe are usually over 150. The insulation and corrosion protection structure and design method have different characteristics from the hot water buried pipeline. Steam temperature is high. The range of temperature stress in the anchorage segment will go far beyond stability conditions. The compensator must be set at regular intervals on the working steel pipe to make the working steel pipe in a sliding state. The tendency of high temperature steam to cause the thermal expansion of the working steel pipe is greater, or a greater occurrence may cause damage to the steel. The steam temperature exceeds the heat resistance of the polyurethane foam. Temperature, therefore, steam buried pipe is usually a composite insulation structure, the inner layer is made of heat-resistant insulation material with high temperature. The outer layer is made of polyurethane foam, so that the gap between the working steel pipe and the outer thermal insulation layer or the outer shell will produce relative sliding between the working steel pipe and the outer thermal insulation layer or the outer shell, which provides a convenient channel for the stability of the water. Therefore, steam buried pipes should have high water resistance. Local water seepage also means that the water seepage of the pipe network is buried directly in the pipeline. The corrosion resistance and water resistance of the pipe shell are easily damaged. The compensator and the fixed pier can make the enclosure appear discontinuous. The water in the soil is infiltrated into the pipe network. The design of the heat insulation structure is easy to make the shell super. For the plastic shell, the shell itself may be hot. For the steel pipe shell, the anti-corrosion layer may be damaged; water infiltration and extrusion of the working steel pipe . It will reduce the overall or partial thermal characteristics of the insulation structure. It can also destroy the corrosion resistance of the shell; for plastic shells, the pressure bearing capacity is low. The infiltrated water is heated. High pressure is generated in the housing. Can burst the shell. can. Directly buried steam pipes are much more complex than hot water pipes. Simply simply change the insulating structure into a composite structure. It is not possible to directly design the complexity of the design of a hot water straight 2 steam pipe network system. 1.1 Different parts of the pipe network system are the same as all the heating pipe network samples, steam pipes and elbows. Head through the fixed bracket. Compensator valves and other piping components consisting of piping systems. Leave the tube. A single steam buried pipe cannot form a complete pipe network system. The strength and waterproof performance of all components together form the strength and water resistance of the pipe network system. therefore. At design time. Qingqing attaches great importance to all parts of the pipe network system in a safe state, so as to form a reliable steam direct buried pipe network. Therefore, the direct buried pipe manufacturer should have the ability to produce all steam prefabricated parts. 22 Product Structure and System Arrangement The product structure design and the pipe network system design together constitute the strength design of the steam buried pipeline system. The foundation of the steam buried pipeline system design is that the working steel pipe can slide freely. In order to release the thermal expansion deformation, therefore. The design of the supporting structure of the prefabricated pipe should be able to meet the sliding requirements of the working steel pipe. For space piping systems, bends in the elbow. At the head and tail, the sliding of the pipe may be accompanied by the lateral displacement of the pipe. According to whether the pipeline produces lateral displacement. Pipe network system design can be divided into two kinds of only axial sliding. Rigid support structures can be used. At the fittings. Without a fixed bracket, the pipeline will produce a compressive deformation of the thermal insulation structure. In the product structure design of the pipe fittings and the nearby pipelines, the working steel pipe should be provided with sufficient space for movement. The outer diameter of the insulating layer and the protective shell should be increased. On the other hand, the support for the working steel pipe should be designed to be flexible. When using a flexible structure design, special attention should also be paid. The scope of the flexible structure should not be too short, otherwise, it will produce a concentrated deformation, resulting in excessive stress due to the working steel pipe. Waterproofing and corrosion protection are important contents of the steam buried pipeline design. Pipe network systems arranged under different geological conditions, the protective layer is also different. Polyethylene shell, the so-called plastic steel model. aspect. The compensator is arranged in the inspection well. Prevent moisture from penetrating into the pipe network system from the compensator. On the other hand. Because of the small water content in the soil. Water penetration is less likely. The thermal performance of the insulation layer can usually be kept stable, and the water resistance of the directly buried part can also meet the design requirements. Simultaneously. This kind of plastic steel mode steam buried pipe cost is low. therefore. When conditions permit, this mode should be preferred. In coastal areas with high groundwater levels, such as Tianjin, Shanghai and Dalian, the possibility of water infiltration increases. After the water is heated. High-pressure steam is generated between the working steel pipe and the casing, and the plastic-steel-type casing will be crushed. Therefore, only steel steam jacketed pipelines can be used. Due to the constant pressure capacity of the steel shell, moisture can be removed by using the exhaust pipe provided in the pipe network system. can. This structure has a certain ability to adapt to the infiltration of water from the soil. In short. For the location in the system and different geological conditions, the manufacturer should be able to provide a variety of forms of prefabricated insulation pipe products. 2.3 Thermal design and strength design Thermal design and strength design are the contents of any heating pipe network design. However, steam is buried directly in the pipeline. Between the thermal design and the strength design there is strong in the steam buried pipe. In addition to reducing the heat loss and thermal dyeing of the heating pipe network, the thermal design of the thermal insulation structure must also control the temperature of the outer thermal insulation layer and the waterproof and rotproof enclosure not to exceed the corresponding heat-resistant temperature. To ensure that the working steel pipe is in the normal design state, the strength design conditions are met. For the temperature field outside the steel tube. In addition to the insulation structure, such as the thickness and composition of the insulation material type. It also depends on the steam temperature and on the ground temperature. In addition. It should also consider the infiltration of moisture in the soil and the sliding of the working steel pipe. Insulation performance degradation factors. And the influence of the thermal bridge formed by the support. To accommodate the changes in the above factors. The thermal insulation design of steam buried pipeline products is calculated by thermal calculation. According to different series to determine. For manufacturers, each series of products should be given a strict scope of application. 3 Steps for Design of Directly-buried Pipeline Network System 3.1 Selection of Prefabricated Pipes for Preserved Shell Structures According to Geological Conditions Corrosion-proof Design of Steam Pipes Directly Buried Pipes of Steel Structures are Applicable to Geological Conditions with Small Soil Water Content; Steam of Steel Jacket Structures Directly buried pipeline has strong adaptability. It can be used on geological conditions where the groundwater level is high. In geological conditions where groundwater levels are relatively low. Insulation materials with insulation properties that are not sensitive to moisture should be selected. After the penetration of moisture into the outside, damage to the insulation material; in the structural design of the components should be used a good waterproof structure. To prevent the infiltration of moisture in the soil to the maximum; in the design of the system, the exhaust pipe should be set reasonably. To facilitate the smooth discharge of water. 32 According to the steam temperature and buried depth, the structural insulation of the insulation layer is determined by adopting different thicknesses of inner insulation and outer insulation. Different steam temperature and cover depth conditions apply. When the steam temperature is low and the buried depth is shallow, the insulation thickness can be reduced. To reduce the cost of the product. In order to facilitate the use of designers, manufacturers should calculate the results based on thermal calculations. According to the insulation structure thickness. Serialized its steam buried pipe products to meet different conditions of use. At the same time, the most unfavorable temperature on the insulation layer and the protective shell should also be provided, providing parameters for the strength calculation. In addition.å² Supports and supports. 1 monument; do not count against the thermal bridge to the temperature position 33 according to the site of the system to select the strength of the support structure design According to the position of the rigid support, into the office of steam directly buried pipe network system of internal forces and stress calculations. It is to check the stress state of the working steel pipe when using the steel sleeve steel structure. The stress of the outer steel tube is also checked; the thrust of the fixed support and the compensation amount of the compensator are calculated; and the displacement of the working steel at the flexible structure is calculated. In order to design a flexible support structure and the degree of insulation. 4 Conclusion Directly buried steam pipe design is a typical system project must be a comprehensive and systematic analysis of all components and components of the steam pipe network of anti-corrosion insulation and strength characteristics in order to design a safe and reliable buried steam pipe network. Harvest date 19W Author brief introduction Liu Shuyi female. 13 students 1 also Harbin. Senior Engineer, currently engaged in HVAC, followed by water plugging work on the 46th floor of miscellaneous fill soil. Ground water must not infiltrate into the foundation pit. If there is no precipitation in excavation, the excavation slope will be steep and the excavation vibration will be affected. The strength of the soil is reduced and the soil will slide. Caused the retaining wall to lean. Engineering pile displacement. Even the pile is broken. 223 Construction Management Q. The current on-site construction management is not standardized, and it is often the project's general contractor and support system. Another earthwork was excavated. Home coordination is not easy, it is easy to get things wrong. Can't dig after digging. Instead, over-excavation or support is often not related to the above-mentioned management system. There are also layers of management subcontracting and subcontracting, which are more prone to accidents caused by cutting corners. 2.3 Monitoring monitoring is an important basis for verifying the correctness of design theory and developing design theory. The monitoring content mainly includes the deformation of the soil in the active and passive earth pressure pits of the foundation pit supporting structure, including the soil subsidence and the lateral displacement of the soil body, the pore water pressure drop and the change of groundwater level. The supporting structure is Monitoring of internal forces and displacements under earth pressure and other loads. There are different monitoring contents and monitoring methods for different types of support structures, for the underground walls. In the case of sheet piles, the main monitoring items are the stress strain of the steel bars in the underground walls or cast-in-place piles, the deformation support of the stress-strain supporting structure of the concrete or the internal forces and deformations of the anchor rods. Many of the deep foundation pit projects are located in urban dense areas and may have an impact on the surrounding environment during construction. They should be closely monitored around the site. Wheel Bearing For HYUNDAI & KIA Wheel Bearing For Hyundai & Kia,Kia Wheel Bearing,Hyundai Wheel Bearing,Hub Bearing Replacement SHAOXING ZHENGHONG AUTO PARTS CO.LTD , https://www.kontinental-bearing.com
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