热式质量流量计在核电厂液体微小流量测量中的应用

根据热式质量流量计的工作原理,以主泵第三级密封泄漏流的测量为例,分析了其在核电厂液体微小流量测量中的适用性,并与现有的测量方法进行了比较。     

在线比对法在流量计量管理中的应用

介绍了利用超声波流量计进行在线流量比对的方法,为监督和控制液体物料的计量准确性,提供了行之有效的计量保证.     

液体涡轮流量计测量结果（A类）的测量不确定度评定

为了确保液体流量量值的统一和准确可靠传递，满足企业和社会生产经营的需要，我公司建立检测流量计仪表的手段——油流量计量标准装置。同时，通过试验还可以研究仪表的动态特性及计量准确度，以便于对仪表进行合理设计，进一步考虑仪表适应的环境条件。是研究参比条件和实际使用条件之间的差异对仪表准确度影响，采用合理的介质换算和维修的方法，作为计量部门开展计量仲裁工作的手段。油流量标准装置对涡轮流量计使用仪表K系数计算流量计示值误差称为A类计算。     

涡街流量计在液体硫磺流量测量中的应用

介绍了400 kt/a硫磺制酸装置中液体硫磺流量计的应用情况.在实际应用中,质量流量计、转子流量计、靶式流量计均不同程度地存在问题.经过分析比较选用了涡街流量计.3年的应用表明,涡街流量计能很好地测量液体硫磺的流量,实现长周期、稳定、可靠、免维护、准确运行,而且性价比较高.     

超声波流量计测定洗油流量

我公司焦化厂粗苯工段原采用涡街流量计在线测定洗油流量,后因循环洗油中的杂质堵塞而损坏。只能靠洗油循环泵电流来判断洗油的流量,阀门与管道阻力等因素易使判断发生错误,影响生产的正常运行。超声波流量测定仪以其方便、快捷和准确等优点已广泛应用于测定水、石油及其它均质液体的流量。在焦化生产中,利用超声波法可从管道外壁测量管内液体的流速,较好地解决了易燃易爆介质的流量测量问题,还可适应多种管径、多种介质和多种流量的测定条件。     

电磁流量计的故障分析

电磁流量计因其可测腐蚀性液体，输出信号与所测流量成正比，显示仪表不需采取线性化措施等独特的特点，目前已广泛应用于各种工业导电液体的流量测量，如对酸，碱，盐等液体的流量测量。     

高温气体与过冷液直接接触凝结制冷循环的性能分析

提出制冷压缩机排出的高温高压制冷剂气体与制冷剂过冷液体直接接触凝结换热的新型制冷循环,结合自然工质氨的热力特性,分析直接接触凝结制冷循环的热力性能,并与常规双级压缩和单级压缩制冷循环的性能进行对比,得出：随着主循环饱和液温度的升高,直接接触凝结制冷循环的性能系数先增大后减小存在最大值,冷凝器散热量先减小后增大存在最小值,流过蒸发器的制冷剂质量流量逐渐增大。在相同蒸发温度和冷凝温度下,当过冷液体的过冷度为20℃时,较常规双级压缩制冷循环,直接接触凝结制冷循环的性能系数提高4.92%,冷凝器散热量减少6.65%,蒸发器的制冷剂质量流量减少7.2%～7.9%;当过冷液体的过冷度为5℃时,较常规单级压缩制冷循环,直接接触凝结制冷循环的性能系数提高6.52%,冷凝器散热量减少3.32%,蒸发器的制冷剂质量流量减少8.58%～8.91%。结果表明氨直接接触凝结制冷循环较常规制冷循环具有明显的优势。     

简论JJG667—2010液体容积式流量计检定规程的新特点

2010年9月国家质量监督检验检疫总局发布了新版JJG667—2010液体容积式流量计检定规程(以下简称新规程),并于2011年3月6日起施行,它替代了JJG667—1997液体容积式流量计检定规程(以下简称旧规程)。笔者多年来从事液体容积式流量计检定工作,通过学习发现这两版液体容积式检定规程有好多不同之处,并且有的地方改动还比较大。本文将这两版液体容积式检定规程中主要的不同之处进行了分析、归纳,以供从事液体容积式流量计检定工作的同行参考。     

变孔径直管液体分布器的研究与设计

本文研究了均匀开孔与非均匀开孔直管液体分布器的流量分配。结果表明,改变孔径可有效地提高流量分配的均匀性。根据修正动量方程和实验数据计算并关联了动量摩擦修正系数。对小孔阻力系数进行了测定和关联。提出了变孔径直管液体分布器的设计方法,并给出设计示例。     

浅谈化工液体原料汽车装卸场地布置

化工企业离不开液体化工原料或是液体成品的运输,而汽车运输是常用的一种运输方式。本文分析描述了化工液体汽车装卸场地在不同设备需求及场地限制情况下的多种布置形式。     

Non-dimensional heat of gasification measurements in the intermediate scale rate of heat release apparatus

Wall-fire spread models require heat of gasification or non-dimensional heat of gasification to calculate mass loss rate or rate of heat release from the wall material. An intermediate scale rate of heat release apparatus was used to measure all the parameters needed to calculate non-dimensional heat of gasification for wood materials. An infra-red pyrometer was used to measure surface temperature. The results of measurements on six wood materials indicate that non-dimensional heat of gasification, if plotted against mass remaining, does not change significantly with external heat flux, but is material dependent.     

Rate of heat release measurements with the Swedish box test

The Swedisn box apparatus was modified to include an oxygen analysis of the exhaust gases to be compared with the conventional exhaust gas temperature measurement. A slow-burning material shows good correlation between the temperature measurement and the rate of heat release. A fast-burning material, however, consumes all the available oxygen, and the temperature measurement becomes a measure of only the thermal properties of the material.     

海信空调风门叶片的翘曲变形研究

采用有限元方法研究了温度场、压力场对注塑件残余应力及翘曲变形的影响，重点讨论注塑件的温度场、压力场的计算，以及热塑性小变形理论下的注塑件翘曲变形计算。对影响薄壳塑件翘曲变形的因素（如模具温度、熔体温度、注射速率、保压压力等）进行分析，提出翘曲产生的原因及相应的改进措施。     

紫外分光光度测量系统在线跟踪研究NKA-II树脂吸附间氯苯胺的行为

利用紫外-可见分光光度法跟踪观察了NKA-II树脂吸附间氯苯胺的行为。利用固—液界面吸附的动力学方程,求取表观吸附速率常数(k),测定了平衡吸附量(Qe),分析计算出了吸附质的亲和能(Ua)及吸附势(E)。实验结果表明,NKA-II树脂吸附间氯苯胺的速率随温度升高而增大,随间氯苯胺浓度的增大而减小;当温度一定时,溶质的吸附量随原始浓度(C0)的增加而增加,吸附势则随着吸附量的增加而降低小;吸附质对吸附剂的亲和能也是随着吸附质浓度的增大而减小。     

Effect of shrinkage and process parameters on the monitoring of bulk and surface stream temperatures in injection molding via the infrared waveguide method

This paper analyzes for the first time the application of the infrared hollow waveguide method for the remote sensing of the temperature decay of polymer streams during injection molding. The key feature of the infrared procedure employed is its low transmission loss of the thermal energy in the mid and far infrared spectral regions. This particular advantage allows the hollow waveguide device to measure not only the bulk temperature within the polymer, as commercially available full‐core optical fiber instruments do, but also the temperature at the polymer surface. Moreover, the hollow waveguide device is able to measure quite low temperatures, which conventional thermometers cannot do either. Experimental trials have been run on a Husky injection molding press in order to investigate the effect of some process parameters and shrinkage on the bulk and surface temperature decay signals. The results showed a drastic deviation between the kinetic behaviors of the surface and bulk temperature traces throughout the injection cycle. Particularly, it was noticed that the cooling rate of the surface temperature was more affected by part shrinkage than the cooling rate of the bulk temperature. The experimental results showed also that temperatures below 60°C could be reliably measured with reasonable signal‐over‐noise ratio. Polym. Eng. Sci. 44:955–964, 2004.     

A study of the effect of the extrusion variables and screw design on the thermal and rheological characteristics of acetal and nylon 66

A detailed study of the effect of several extrusion variables was made on the rheological and thermal properties of Delrin II acetal homopolymer and Zytel 42 polyamide 66 materials. A 63.5 mm Davis Standard extruder was used to measure the effect of screw design, screw rpm, die and head pressure, and melt temperature on the rheology of acetal and nylon 66 resins. A single stage metering screw was used to determine the effect of screw geometry and viscous heating on the melt viscosity breakdown and the rate of degradation of each polymer. The melt temperature was measured in the melt stream in the channel and correlations are shown between ideal melt temperature predicted from the rheology data and the actual loss of properties of each polymer due to viscous heating. The paper also discusses how to measure the melt temperature accurately in extrusion, and to use it as a key indicator to optimize the extrusion process, and to control the rheology, thermal stability, and the molecular weight of a polymer during processing.     

Electron beam irradiation induced grafting of acrylonitrile to polyethylene powder

This study focuses on the influence of various parameters on the post-irradiation grafting of acrylonitrile monomer to a low density polyethylene powder having an average particle size of 20 μm diameter. The type of radiation used was 0.8 MeV electrons with a dose rate of either 0.1 Mrad/min or 4.0 Mrad/min. Irradiations were carried out in vacuum, air, and dry oxygen environments at room temperature to total doses ranging from 1 Mard to 15 Mrad. Several experimental techniques were used to investigate various interrelated aspects of both the graft copolymer product and the graft process, including infrared spectroscopy to measure percent graft, electron spin resonance to measure radical concentrations, scanning electron microscopy to investigate surface morphology, and differential scanning calorimetry to measure crystalline content. Comparisons of the percent graft determined from different probes were found to be consistent. The dose dependence of grafting exhibited a linear relationship below 8 Mrad. Initiation by both alkyl and peroxy radicals at 77°C was supported by results of decreased grafting with decreased temperature, increased dose rate or vacuum irradiation. Decreased grafting after oxygen irradiation suggested a unique change in grafting mechanism. Higher grafting yields were found for quenched relative to annealed samples. The amount of extractable homopolymer formed was found to be ～ 10% at a dose of 10 Mrad and a dose rate of 4 Mrad/min.     

Kinetics of solvent-assisted dyeing of acrylic fibres

The kinetics of dyeing acrylic fibres with cationic dyes in the presence of small amounts of the solvents ethylene carbonate, propylene carbonate, nitromethane and iso-amyl alcohol has been studied. The time of half-dyeing was taken as a measure of the rate of dyeing, which was found to decrease with increasing concentration of the solvent in the dyebath. A linear correlation was observed between the rate of dyeing and the change in glass transition temperature of the fibre.     

镁合金化学镀镍溶液稳定性

为了开发出长寿命高稳定性镁合金化学镀镍溶液,通过添加硫脲、碘酸钾等稳定剂,研究了pH值、温度对镀液的稳定性能、镀速、镀层质量等因素的影响。采用称重法测定镀层的沉积速率,沉积到镀件上的镍量占溶液中消耗镍量的百分比来表示溶液的稳定性,NaCl溶液浸泡实验评定镀层的覆盖度,热震实验评定镀层的结合力,极化曲线表征镀层的耐蚀性。 结果表明,沉积速率随硫脲、碘酸钾浓度的增大先升高后降低,碘酸钾对镀速的影响不如硫脲显著。添加硫脲0.5 mg·dm^-3时稳定常数最大值达89.25%,添加碘酸钾 5 mg·dm^-3时,稳定常数达82.45%。采用pH值为5.0的含硫脲的镀液,（82±1）℃施镀,获得的Ni-P镀层和镁合金基体之间没有缝隙,结合紧密,而且Ni-P镀层均匀致密。硫脲不仅能提高沉积速率,而且也催化镁合金表面,提高沉积效率。     

A comparison of induction time and crystallization rate for syndiotactic polystyrene

One objective of this study was to measure the crystallization parameters for syndiotactic polystyrene (M_W = 244,000) to support a computer simulation of this material in an injection molding application. A second objective was to introduce a new crystallization rate equation that adequately predicts crystallization rates over a broader temperature range than the Hoffman‐Lauritzen equation. A third objective was to establish a new clearly defined method for determining the true induction time of a semicrystalline polymer as a function of temperature. The new crystallization rate equation introduced in this study has been formulated to give appropriate crystallization rate constants for all the temperatures currently usable with the Hoffman‐Lauritzen equation. In addition, this new equation also predicts appropriate crystallization rate constants outside the range of the Hoffman‐Lauritzen equation from temperatures significantly below the glass transition temperature, T_g, to temperatures significantly above the melting point, T_m. Interestingly, the isolation of the true isothermal induction times from apparent induction times in this study nicely mirrored the isothermal crystallization rates at each specific temperature. Both the true induction time and the crystallization rate curves were found to be similarly unsymmetrical as a function of temperature. Also, the temperature at the minimum induction time and the temperature at the peak crystallization rate determined from nonisothermal crystallization rate measurements were found to be nearly identical. Consequently, the results from this study strongly suggest that there is a significant and potentially very useful relationship between induction time analysis and crystallization rate kinetics.