Cold welding sealing of copper-water micro heat pipe ends

The quality of micro heat pipe(MHP) is strongly affected by sealing technology. Based on the analysis of requirements of sealing technology, a cold welding technology was presented to seal MHP. In the cold welding process, compression force was used to flatten micro groove copper(MGC) tube. Then the bonding of MGC tube was reached because of intensively plastic deformation of MGC tube under pressure. It is found that the plastic deformation area of the cold welding of MGC tube can be divided into three sections. The deformation of micro grooves in each section was investigated; the influence of the dimensions of cylindrical heads on the weld joint shape and strength was studied; and a comparison between smooth copper tube and MGC tube was done. The results show that a groove compression stage exists in the cold welding of MGC tube besides a flattened stage and a melting stage.

Development and Investigation of a Miniature Copper-Acetone Loop Heat Pipe with a Flat Evaporator

The paper presents the results of development and investigation of a copper miniature loop heat pipe (LHP) with acetone as a working fluid. The device was equipped with a flat evaporator measuring 80 × 42 × 7 mm and vapor and liquid lines with an outside diameter of 3 mm, whose lengths were 145 mm and 175 mm, respectively. The LHP was tested at heat loads from 5 W to 60 W, different orientations in the gravity field and heat-sink temperatures from -40°C to +50°C. It is shown that the LHP retains its efficiency at all testing conditions. It is also mentioned that at a heat-sink temperature of +50°C the device operates in the mode of constant conductivity in the whole range of heat loads, and in this case a minimum thermal resistance of the “heat source-heat sink” system equal to 0.16°C/W is achieved, which is independent of the LHP orientation in the gravity field.

Field load testing of copper extraction aeration pipes under simulated high heap pile

Recently a research team at Ohio University,USA,conducted a unique full-scale feld load test to simulate the aeration pipe installations at a copper extraction mine operated in Chile.The overliner material taken from the mine was used in recreating the in situ conditions.Electric heaters were utilized to raise the temperature inside each pipe to simulate the essential element of the copper extraction process.The maximum vertical deflection reached by the test pipes was close to 20%,when the simulated heap pile height was 80 m.The plastic pipes and the overliner material were also tested in the laboratory.Based on the results,the maximum heap pile fll depth was recommended for the aeration system.The results indicated that the vertical deflection was the primary performance index for the aeration pipes installed in heap piles at mines.Lastly,the pipe made of polypropylene resin was super.

Ceramic-lined compound copper pipe prepared by SHS process

Self-propagating high-temperature synthesis(SHS) is a new kind of material synthesis technique, and has characteristics with respect to low energy consumption, short synthetizing time, high production quantity, high product purity and no environmental pollution. When SHS combines with centrifugal casting, ceramic-lined compound copper pipe(CLCCP) can be produced, the inner surface of copper pipe can produce ceramic coatings having good wear and corrosion resistance. In order to increase the densification degree, combining strength and toughness of ceramic layer, the effects of additives such as SiO2, CrO3, Na2B4O7 and ZrO2 are researched, adding SiO2 and CrO3 in thermite, the densification degree of ceramic layer increases, adding Na2 B4 O7 in thermite can increase combining strength, adding ZrO2 in thermite can increase the toughness of ceramic layer. CLCCP is used in tubular billet crystallizer, having excellent service effects and decreasing the production cost of tubular billet.

Elimination of Oil Residual inside the Copper Pipe Using Ladder Technique

This study presents the methodology to eliminate oil residual in copper pipe due to rolling process for manufacturing coil used in air conditioner. The pressure caused by Nitrogen flow rate was applied starting from 0, 5, 10, and 15 bar, respectively which was depending on time delay and pipe length. The developed system was divided into 2 modules: Parallel pressure ladder module (PPLM) [1] and Serial pressure ladder module (SPLM) which were experimented with 2 sizes of copper pipe: diameter 7.29 mm, thickness 0.25 mm, and length 10 km, and diameter 8 mm, thickness 0.25 mm, and length 10 km. From experiment, it can be noted that PPLM would perform better in elimination of oil residual compared to SPLM. About 97.44% (0.04 mg/m) and 97.59% (0.05 mg/m) of oil residual can be respectively eliminated from diameter 7.29 mm pipe and diameter 8 mm pipe which exceeded the standard allowance of 30% or 0.1 mg/m. Moreover, the cost of Nitrogen can be reduced by 6.25% per month.

脉动热管太阳能集热器传热性能实验研究

以真空玻璃管为载体、石蜡为相变储热材料、脉动热管和铜管为传热元件,对比分析了充液率φ=50.0%的脉动热管太阳能集热器与铜管太阳能集热器在相同辐照度下的集热性能。研究结果表明,当辐照度大于0 W/m^(2)时,脉动热管太阳能集热器相比于铜管太阳能集热器管壁温度提高了40℃;相较于铜管太阳能集热器,热源温度越高,脉动热管太阳能集热器吸热能力越强,传热效果越好;在相同的辐照度下,相比于铜管太阳能集热器,脉动热管太阳能集热器内的石蜡达到熔点的时间缩短了13%;脉动热管太阳能集热器输出的热量比铜管太阳能集热器高0.5 kJ,随着辐照度的增强,热量差值将会更大;脉动热管蒸发段和冷凝段壁面与其相接触的传热工质会形成一种准平衡态,蒸发段与冷凝段的传热能力呈反比关系,当蒸发段传热能力下降时,冷凝段传热能力上升,保证了集热器的稳定运行。

暖通空调给排水管道的表面改性与性能研究

为提升暖通空调铜合金排水管的表面性能,采用化学镀的方法在铜合金排水管表面制备了Ni-P/TiN镀层,研究镀液中TiN质量浓度对化学镀层物相组成、表面及截面形貌、硬度和耐磨性能的影响。结果表明,无镀层的铜合金基体主要物相为CuZn和CuZn5,表面镀层主要由非晶Ni组成;在基础镀液中适当添加TiN会形成镀层质量较好的含有胞状颗粒的镀层,而过量的TiN添加会使得镀层质量恶化。相较铜合金基体,表面镀层的硬度明显更高,且表面镀层硬度会随着镀液中TiN质量浓度的增加而增大;当TiN质量浓度为10 g/L时,表面镀层的硬度和磨损率分别为633 HV0.1和0.93×10^(-8)g/(r·N),具有相对较好的耐磨性,此时的磨损机制主要为氧化磨损。

铜铝双金属复合管二辊纵轧成形工艺研究

铜铝复合管主要应用于冰箱、空调冷热交换器等的连接管件,其机械性能优良、可加工性好、经济性强,同时纵轧管作为一种高效的管材成形方法,适用于铜铝复合管的轧制成形。本次对轧制变形、孔型系统、轧制力、伸长率等进行理论研究和有限元模拟复合管连轧成形分析,并结合实验进行验证,实验结果表明复合管内外壁均光滑无缺陷,机械结合力为2.92 MPa,实现有效复合。轧制力的理论值与实测值、理论值与仿真值的平均误差分别为16.44%、15.33%;铜层、铝层、总壁厚的仿真值和实测值的平均误差分别为2.36%、1.62%、2.07%;伸长率的理论值与实测值、理论值与仿真值的平均误差分别为7.94%、5.11%,均在合理范围内。该结果验证了铜铝双金属复合管轧制成形工艺的理论研究和仿真分析的准确性和可靠性。

适用有机液体脱氢的热管换热器传热实验研究

为提高有机液体脱氢反应器的传热性能,采用热管和泡沫铜强化传热技术,设计一种适用于有机液体脱氢的新型换热器。以空气为换热工质,通过实验分析入口温度和流量对传热量、传热系数、效能和?效率等传热性能的影响,并对比分析泡沫铜与热管对换热器传热性能的强化程度。结果表明:所用热管在有机液体脱氢温度下的传热效果良好,当工作温度为473 K时,当量导热系数达到1407.9 W/(m·K);对于热管换热器,当热风入口温度为453~493 K、热风流量为0.6~1.8 m^(3)/h、冷风流量为0.6~1.5 m^(3)/h时,提高热风入口温度和流量能有效提高传热性能;此外,通过对比发现,基于热管和泡沫铜强化的换热器,传热量可提升33.3%,效能可提升31.0%。

微束水蒸气等离子弧焊在空调铜管钎焊中的应用

铜管是制冷设备的重要原材料,生产中通常采用气体火焰钎焊对铜管接头进行焊接。但传统的气体火焰钎焊存在诸多缺点,故引入微束水蒸气等离子弧焊工艺方法,探究其焊接铜管的可行性并确定出合适的焊接工艺参数。通过对5组不同规格的铜管接头在6个焊接电流档位下分别进行焊接试验,对试验样本焊后的外观和内部结构进行观察、分析、对比,验证了该方法相比于气体火焰钎焊方法的有效性,并获得了各类铜管接头合适的焊接电流档位。与气焊相比,使用微束水蒸气等离子弧焊工艺在合适的焊接工艺参数下进行焊接,具有较高的效率、稳定性、易用性和安全性,能够为空调铜管的焊接和维修提供一种新的工艺方法。

高速列车铜合金管路密封连接绿色感应钎焊技术研究

为解决传统火焰钎焊和高温银钎料存在的质量问题、环境污染、安全风险、成本高昂等问题,研究了一种适用于高速列车铜合金管路密封连接的绿色钎焊技术。采用低银复合钎料BAg34CuZnSn复合钎料和感应钎焊技术,对TP2Y2紫铜管套接接头进行钎焊连接,通过OM、SEM、EDS及拉伸试验等分析测试方法,分析了复合钎料感应钎焊紫铜管钎缝形貌、钎料填充深度、钎焊接头界面组织、力学性能以及钎焊热循环对紫铜管组织性能的影响。结果表明,在输出功率40 kW、钎焊电流100A和钎焊时间40 s的条件下,钎料能够完全有效填缝,实现TP2Y2紫铜管套接接头的密封和高强连接,钎缝外观光滑、连续,母材无凹陷性熔蚀。钎缝组织主要由Ag固溶体和Cu固溶体组成,钎缝组织连续致密,无气孔、裂纹等缺陷。紫铜管钎焊接头的平均抗剪强度达到222.7 MPa,能够满足大熔深铜管结构的可靠连接。

金刚石涂层游动芯头制备及其在铜管生产中的应用

通过沉积方式和旋转装置设计,采用直流电弧等离子体喷射法在硬质合金游动芯头表面均匀沉积金刚石涂层,并利用白光干涉仪、扫描电子显微镜、Raman光谱仪和压痕法对涂层的表面粗糙度、形貌、质量均匀性和膜–基附着力等进行测试分析。结果表明:金刚石涂层抛光后的表面平均粗糙度S_(a)为76.4 nm,金刚石涂层脱落位置到压痕中心的平均距离为287.9μm,且各位置的金刚石涂层厚度均匀性和质量均较好。将制备的金刚石涂层游动芯头应用于高精度精密铜管生产线中,与硬质合金游动芯头对比,其在降低劳动强度、保证铜管一致性和延长芯头使用寿命方面都有显著效果。

抗氧剂1024在铜嵌件聚丙烯管件中的应用研究

铜嵌件聚丙烯管件在建筑给排水领域广泛使用,然而铜的存在会加速聚丙烯材料的热氧老化。该研究在聚丙烯树脂中引入抗氧剂1024,通过长期热氧老化实验以及在力学性能、OIT、熔融指数方面的测试,结果表明含有抗氧剂1024的聚丙烯具有强的抗铜热氧老化性能。加入0.3%的抗氧剂1024对聚丙烯的力学性能保持较好,老化后强度为21.6MPa,仅降低14.6%;而管件内层OIT下降速度缓慢,在180天老化后依然保持为13.7min。微观形貌研究发现,抗氧剂1024可以在聚丙烯与铜接触表面形成稳定络合物。含有抗氧剂1024的聚丙烯铜内嵌管件,其热氧老化性能与镀镍黄铜管件相近,具有较好应用前景。

基于图像处理的换热器换热铜管尺寸测量研究

针对换热器换热铜管直径非接触及自动测量问题,提出了一种基于图像处理的测量方法.首先利用CCD相机采集换热铜管图像,然后通过灰度化、滤波去噪、二值化及数学形态学处理等方法对图像预处理;接着采用Canny边缘检测算子绘制边界轮廓,并获得换热铜管直径像素尺寸;最后结合相机标定法将换热铜管像素尺寸换算为实际物理尺寸.将该测量结果与游标卡尺测量结果对比,计算得到误差为1.6%,提高了测量精度.

多工位紫铜管口径扩缩装置的研制

在中央空调多联机安装系统中,分歧管的作用是将管道中的制冷剂分流到室内机中。空调分歧管的进口和出口均由变径的多节紫铜管组成。变径的多节铜管加工难度较大。针对传统的手工扩缩技术效率低等问题,本文设计了一种高效、结构简单、操作便捷的多工位铜管口径扩缩装置。该装置集铜管进料、扩口、缩口、打磨、推料为一体。利用该装置能够对若干个铜管进行连续操作,提高了铜管扩缩与打磨的效率,可以显著降低企业的人力成本。

套管式换热器管路用铜合金组织及性能研究

地源热泵套管换热器对其内部流水管路的抗腐蚀性能及耐磨性要求极高。研究主要针对T2紫铜管及B10铜镍合金管在0.0598 mol/L NaCl和0.1 mol/L NaHSO3混合溶液中的腐蚀速率,分析两种合金管的腐蚀行为及抗腐蚀性能,并综合考虑两种合金的力学性能、加工工艺、材料成本,使选材最优化。结果表明:在3.5%NaCl和0.1 mol/L NaHSO3溶液中,T2紫铜管以均匀腐蚀为主,最大腐蚀深度约为0.121 mm,B10铜镍合金表面轻微腐蚀,局部存在点蚀坑,最大腐蚀深度为0.041 mm,铜镍合金管的抗腐蚀性能明显优于紫铜管;B10铜镍合金的抗拉强度及硬度分别为450 MPa、140 HV,力学性能明显优于紫铜。综合抗腐蚀性能、力学性能、加工工艺、材料成本考虑,认为B10铜镍合金更适用于制造地源热泵套管换热器内管路。

空调连接管发黑失效机理分析

在空调系统中,连接管是传输冷热介质的管道,其表面会因温度差异而产生热量传递,导致能量流失,通常连接管均会套保温管进行保温,售后反馈采用橡塑保温管在放置一段时间后会出现铜管发黑的情况。本文通过宏观检查、微观检查、EDS、金相分析、化学分析等手段进行分析,结果表明发黑物质的成份主要是硫化铜(CuS)。可从生产配方上优化以解决保温管导致铜管发黑问题。

精密铜管生产线在线质量控制系统研究

精密铜管因其卓越的导热性和电导性,在众多工业领域中发挥着重要作用。随着工业需求的不断提高,精密铜管的质量控制显得尤为重要。文中通过分析精密铜管生产线的组成和工艺流程,探讨了精密铜管的应用领域及其质量要求,并着重介绍了在线质量控制系统的设计与实施。通过引入在线质量监测技术和质量数据分析处理,该系统能有效提高精密铜管的生产效率和产品质量。此外,文中还探讨了系统的设计原理、硬件配置与软件开发,并通过案例分析展示了实施效果,为精密铜管生产线的质量控制提供了新的思路。

Sintering technology for micro heat pipe with sintered wick

In order to study reasonable sintering technological parameters and appropriate copper powder size range of micro heat pipe (MHP) with the sintered wick, the forming principle of copper powders in wicks and MHP's heat transfer capabilities were first analyzed, then copper powders with different cell sizes and dispersions were sintered in RXL-12-11 resistance furnace under the protection of the hydrogen at different sintering temperatures for different durations of sintering time, and finally the sintered wicks' scanning electron microscope (SEM) images and their heat transfer capabilities were analyzed. The results indicate that the wick sintered with copper powders of larger cell size or smaller size range has better sintering properties and larger heat transfer capabilities; and that the increase of either sintering temperatures or sintering time also helps to improve the wick's sintering properties and heat transfer capabilities, and the former affects more obviously than the latter. Considering both its manufacturing cost and performance requirements, it is recommended that copper powders with the size range of 140-170 μm are sintered at 900-950℃ for 30-60 min in practical manufacturing. In addition, two approaches to improve wick's porosity are also proposed through theoretical analysis, which suggests that the larger the wick's porosity, the better the heat transfer capabilities of the MHP.

Health Safety of Main Water Pipe Materials Supplied in China Market

Objective To assess the health safety of copper, steel and plastic water pipes by field water quality investigations. Methods Four consumers were randomly selected for each type of water pipes. Two consumers of every type of the water pipes had used the water pipes for more than 1 year and the other 2 consumers had used the water pipes for less than 3 months. The terminal volume of tap water in copper and steel water pipes should be not less than 0.1 liter, whereas that in plastic water pipes should be not less than 1 liter. Results The mean values of the experimental results in the second field water quality investigation of the copper and steel water pipes met the Sanitary Standards for Drinking Water Quality. The items of water sample of the plastic water pipes met the requirements of the Sanitary Standards for Drinking Water Quality. Conclusion Copper, steel, and plastic pipes can be used as drinking water pipes.