Buried pipe insulation Features What? What buried insulating pipe construction scheme?
Acronym hydrocarbon ester buried insulating pipe tube, which is based substrate is a substrate, the coating material is an ester, so it not only maintains the high strength and toughness of the base material, and has a high pressure, impact resistance, anti-cracking and other properties , and conventional pipe insulation, compared pipeline, more secure and reliable, economical and environmental protection, good insulation properties, effective solution to the high-temperature thermal town district heating heat transport 130 ℃ -600 ℃ with buried insulating pipe, the slide lubrication and waterproofing the exposed end of the tube.not only has the traditional trench laying of pipelines and overhead incomparable advanced technology, practical performance, but also has significant social and economic benefits, but also energy-saving heating of effective measures. Buried pipe insulation technology using buried heating pipe, marking China heating pipe insulation polyurethane technology has entered a new starting point. It can be said in the art can replace the water supply pipe insulation and gas pipelines, the installation method of an ordinary buried insulating pipe similar to pipe insulation. The next set of network Yin Xiao Bian to introduce more about buried pipe insulation for everyone, including: buried pipe insulation performance characteristics, construction plan, construction precautions, composition, Notes on maintenance. 1, excellent anti-rust properties: resistance to various concentrations of acid, alkali, salt corrosion, fouling rate in other product life. 2, no ignition performance: the additives used in the polyurethane raw material, which does not meet national standards which ignitability hydrocarbon ester of a composite structure, does not fire performance better than other product. 3, has a very powerful adhesion? Base outer wall and blasted after blasting efficiency, which coating adhesion ≥30N / 10mm. 4, excellent mechanical properties: better able to withstand harsh environments buried insulating pipe coating toughness, high mechanical strength of the substrate, with superior ability to withstand impact or bending outside influences. The combined solid convenient, quick connectors may be used combined merged, combined card, having a very powerful interchangeability. First, the construction preparation (1) the worker shall be subject to pre-job professional training certificates. Materials (2) mending used, there should be quality certification, product design and should comply with the relevant technical standards and specifications. (3) the accuracy of the mending process monitoring of the appliance should be checked before proceeding to the next step after the inspection. (4) the factors affecting the quality of the fill opening and the determined key parameters mending process shall be documented and used in mending process.(5) before opening up, in this project should be matching between the inlet pipe and fill mending materials for process evaluation test to confirm mending process raw materials, and well-matched to meet the requirements of the construction project. After the (a) step of the construction process (b) preparing a pipe welding process is completed by the non-destructive testing and inspection, mending received notification of the line without affecting the construction, fill port construction for the pipe. 1, before installation remove soil and dirt across the inner and outer sleeve portion and pipe, plastic bonding site to ensure clean. 2, to determine the size of the lap joint sleeve and the outer sleeve of polyethylene, the joint bushing placed at the joint, to ensure centering the outer sleeve, and then shrinking band installation. (D) mounting a thermal zone, ready to (1) remove soil and dirt heat shrink tube and the outer parts of the adhesive, is greater than the clear width of the thermal zone, where there is oil clean with alcohol, and the viscosity roughening contact portion, roughening width greater than the width of the heat-shrinkable. (2) adhesion areas should ensure that there is water the dry or dry bake lamp. 2, the installation (1) determining the length of the lap belt and the thermal shrink sleeve. (2) taken with length of heat-shrinkable. One end (3) to cut shrink band chamfer 50 × 15mm. (4) The thermal adhesive layer inwardly covering band at the interface, and to ensure thermal zone at a centered position in the overlap. (5) low heat shrink sequentially with two overlapping baking subbing layer to overlap and secure the micronized and then baked gland glue has centered on the buckle lap seam, and back and forth with the fire until uniform baking gland and gland close thermal bonding the adhesive tape completely free of bubbles and edge lifting, during heating or pressure roller can be used to smooth the glove capping it with thermal zone. (6) After pressing gland, from the middle of the thermal zone starts, first the sleeve lap side baking, the baking should start from the bottom, and at the follow up regulation with baking inside-out, to avoid bubbles, (7) the flame length adjustment, along the first thermal zone uniformly heated to the middle ring, the middle finish after shrinkage heating sequence ends, the heating process to ensure that the gun should be moved back and forth with or without local thermal overheating. (8) should be carefully observed if heat shrinking heat shrinkable band edge with a hot melt overflow. (9) to be completed shrinkage, again check whether the thermal zone and Gland Alice and the presence of bubbles, if bubbles should be excluded to ensure thermal zone patch and gland formation. (10)Non-immersion insulation materials, insulation found flooding, water cut-out portion of the insulation material should be re-insulation. (E) an airtight test, the outer sleeve to drill a hole in one end portion of the pressure gauge mounted in the hole and tighten the fixing bolt. 2, open air compressor, pressure tested with soap and water rose to 0.02Mpa, not leak. 3, when the heat-shrinkable polyethylene strip should be repaired leakage site, and air tightness test, after passing the urethane foam before proceeding. 4, the pressure on the outer casing reaming drill hole is also foamed and discharging vent. (F) When the polyurethane foam tightness test and satisfies predetermined qualifying post may be made of polyurethane foam. 2, using a polyurethane raw material. 3, the length of the interface according to the injection amount calculation polyurethane tapping test performed after 4, the overflow from the hole completely cured foam, the foam should enrich full. 5, a polyethylene occluder: a plastic closure sealed foam cells. Third, the construction site conditions to claim 1, buried insulating pipe, although very low water absorption of the polyurethane, but not immersed in water. Construction must be set and drain sump, sump inner diameter of 0.8m, bottom deeper than the groove bottom 0.5m, 0.2m × 0.2m along the groove ditch digging, the groove bottom slope aspect sump 1%, using the drain pump (with standby pump) water pumped in time, to ensure that when operating dry socket pipe installation. 2, the joint working pit size should meet construction specifications, in particular, the bottom of the bottom of the spacing duct should be as large pits some work to ensure grilled thermal zone at the bottom of the lance pipe has sufficient space to prevent thermal zone drain grilled or baked inadequate phenomenon occurs along the lower circumference. 3, the construction site has a full-time person to manage drainage, 24 hours a day, to prevent the pipe being immersed in water. 4, in order to ensure the construction quality, there should be a reasonable time limit. 5, if conditions permit, should be taken after a plurality of trenches in the insulation pipe welding joint insulation well is completed, and then placed in the trench program suspended. 6, the working pit shall decide whether to set up support to ensure the safety of construction workers depending on the circumstances depth, soil and water table. buried insulating pipe Construction Notes arise from the practice of engineering quality point of view, should pay particular attention to the following issues in the design and construction of: a, design and construction, we must truly understand for buried way heat pipe is divided into and has no compensation buriedBuried compensation in two ways, really two ways to master their works, characteristics and applications, so a reasonable choice in the design, the construction of safe, reliable and economical. 1, the first to grasp the concepts: YES compensation Buried way, thermal elongation is solved by the pipe line natural compensator and a compensator (such as a square and a bellows compensator), so that the thermal stress is small; uncompensated linear buried laying, simply put, it is the pipeline without any compensation measures when heated, but by the strength of the pipe itself to absorb thermal stress. The basic principle of laying uncompensated: When installing piping, the piping is first heated to a certain temperature, and then welded and fixed to the pipe, when the pipe mounting restored to temperature (temperature decrease), pipe previously subjected to a certain tensile stress. When the pipe through hot working, as the temperature rises, the pipe stress is zero, while continuing heating, the compressive stress of the pipe increases when the temperature is raised to the working temperature, the pipe stress (thermal stress) is still less than the allowable stress. Thus, the pipe can not work properly compensating apparatus. This non-compensation applications fourth strength theory, the need for warm-up pipeline construction, construction is too much trouble, but at home and abroad has a large number of engineering practice, the reliability of calculation, to ensure safety. Another way in recent years, no compensation calculation method proposed by the Institute of Beijing Gas heat stress and stability analysis using classification, application of the third strength theory. In this way full potential of steel plasticity, easy construction, no warm-up. 2 two lay buried depth consideration of different factors. (1) When determining compensation has adopted Buried way, consider only the burial depth due to ground load can not destabilize the pipeline, from the viewpoint of economy, construction and convenient. When there is compensation Buried way, in shallow as possible, typically greater than 0.6 m Futuhoudu to, and independent of the diameter size. Construction Notice buried insulating pipe (2) When no compensation Buried way, the depth of buried pipeline requirements to be considered stable, and stability is mainly soil thickness, generally buried deeper than with a compensation, not preheated when employed when uncompensated buried pipe, casing depth should be small \”city heating network design specification\” (CJJ34-90) section 7.2.15 executed Futuhoudu should be proportional to the size of the diameter. 3, whether the design is still laid-free compensation compensation laying, the longer straight pipe principle, less intermediate branch, when the heating medium does not exceeds 100 ℃, preference should be givenLaying without compensation, otherwise, we should consider compensation laying. Specific trunk heating network should be no compensation laying and branch courtyard pipe network should be used to compensate laying there, but there are some designers prefer to compensate laid, should promote optimal design. Second, before the construction of the necessary casein manufacturers of prefabricated polyurethane insulation buried pipe research, after careful inspection approach, failed to reject the use of pipe insulation. Third, in the buried pipeline construction, welding work is a key to ensuring project quality. 1, must obtain a certificate of welders, only within the permitted range of certificates welding, no certificate can not participate welders welded construction. 2, welding pipe joints, should do the pit, and should pay attention to the joint fight and groove joint welding quality. Fourth, mounting bracket, a variety of construction quality directly affects the life of the well and pipeline construction quality, such as the well water is not good, it will make part due to flooding destroyed. Therefore, the construction should be careful to ensure construction quality. After the pressure inside the pipe was raised to 1.5 times the working pressure: five, must pay attention to the pressure pipe buried pipe, under pressure conditions satisfied, first, the net irrigation exhaust air, and then do the two steps: 1, strength test in the regulator 10 since the beginning no leakage. 2. Tightness test: when the pressure in the pipe down to the working pressure, with a hammer 1kg one by one beat of the weld around the weld inspection, no leakage after 30 minutes and the pressure drop does not exceed 0.2 atm i.e. qualified. 3, requires good pressure test specification should record. buried insulating pipe structures 2, insulation layer: a rigid polyurethane foam. New insulation scheme employed 20mm ~ 30mm inner airgel mat, the outer high-pressure polyurethane foam technology. 3, the protective case: high-density polyethylene or fiberglass. 4, leakage alarm line: the production of high temperature insulation pipe buried in the insulation layer near the steel pipe, buried alarm line, once leakage occurs somewhere in the pipeline, by conduction line alarm, the alarm can be on a dedicated instrumentation and shows the exact location and extent of the size of the leak leaking to notify maintenance personnel to quickly deal with pipe leakage, ensure safe operation of the heating network. Precautions maintenance buried insulating pipe a, to avoid alcohol, gasoline, or other chemical solvents other stains. Buried insulating pipe surface if the stain, do not rub hard Meng, mayWith warm gently remove tea stains, after evaporation of water, until the sol coated with a little of the original site, and then again several light mill to form a protective film. Second, avoid scratch hard objects, buried insulating pipe during maintenance, do not use the cleaning tool touches the surface, usually pay attention not to let the hard metal or other sharp touch buried insulating pipe, protect the surface without bruising traces . Third, pay buried insulating pipe cleaner outer jacket pipe maintenance. The outer protection pipe is made of high density polyethylene material is made, if the outer protective tube buried pipe insulation once destroyed will affect the internal structure. Yin above is set small as we explain the network Features buried insulating pipe, construction scheme, construction considerations, structural composition, when maintenance considerations. You know, pipe insulation is an important factor affecting energy conservation, development and application of pipe insulation is more and more widespread attention around the world. After the 1970s, foreign widespread attention to the production and application of pipe insulation, and strive to significantly reduce energy consumption, reduce environmental pollution and the greenhouse effect. Foreign insulation industry has a long history, and new insulation materials are constantly emerging. Prior to 1980, the development of pipe insulation in our country is very slow, one of the few plants can only produce a small amount of insulation buried underground pipe insulation, but the Chinese insulation industry after 30 years of effort, especially after nearly 10 years of rapid development, many products from scratch, from single to diversity, the quality from low to high, more and more common. Hydrocarbon ester materials are commonly used internationally insulation material. Hard hydrocarbon ester having many excellent properties, are widely used in Europe and the United States insulation field. Insulation materials in Europe and other developed countries, about 49% hydrocarbon ester materials, while the proportion in China is still less than 20%. Thus, pipe insulation material hydrocarbon ester in the development of China as well as a lot of space.