基于PDCA循环的高温爆破技术

为确保在高温火区安全爆破的前提下,进一步增加高温火区爆破作业规模,稳步提升露天煤矿岩石剥离作业进度,结合宁夏大石头露天煤矿爆破现状,针对降温效果、孔内积水、炸药选择等进行深入研究.将PDCA循环安全管理与布孔钻孔、信息化测温、炮孔降温等进行有效结合,准确掌握了高温区分布情况,制定合理的降温方案;并针对裂隙区炮孔升温反弹...     

全孔蓄水法在高温火区爆破中的应用

针对高温炮孔因裂隙多导致蓄不住水的情况,将内层带有不透水材料的套管快速下放到炮孔并在短时间内注满水,在套管中装有模拟药卷并采用热电偶测量套管中的水温变化。结果表明:全孔蓄水可使工业炸药与起爆器材长时间保持在最高温度不超过水浴温度的环境中,因此能大幅延长高温火区装药施工时间。探索出高温火区的全孔蓄水爆破方法,并通过爆区规模试验,效果良好,该方法能保证施工安全,同时基本解决高温火区较大规模爆破的问题。     

露天煤矿火区成组炮孔与双人制起爆实践

针对露天煤矿火区爆破安全和水资源匮乏降温困难的问题,结合福强露天煤矿火区爆破开采工程,将高温炮孔分为2类,第1类为120以下的炮孔,第2类为120℃以上的炮孔,并确定高温炮孔必须降至120℃以下再实施爆破作业。提出了成组炮孔设置形式和双人制作业,谁装药谁起爆的现场组织管理模式,以减小起爆安全距离或多组轮流作业方式,完成起爆主线与起爆器的连接、充电、起爆一系列操作。有效地解决了露天煤矿火区爆破开采中降温困难、爆破器材受高温作用发生燃烧等问题,阻止了因多人作业现场混乱和误操作等原因导致的早爆事故,保障了煤矿火区爆破作业安全,并取得规模爆破的效果,可为类似露天煤矿火区爆破开采提供参考。     

露天煤矿火区成组炮孔与双人制起爆实践

针对露天煤矿火区爆破安全和水资源匮乏降温困难的问题,结合福强露天煤矿火区爆破开采工程,将高温炮孔分为2类,第1类为120以下的炮孔,第2类为120℃以上的炮孔,并确定高温炮孔必须降至120℃以下再实施爆破作业。提出了成组炮孔设置形式和双人制作业,谁装药谁起爆的现场组织管理模式,以减小起爆安全距离或多组轮流作业方式,完成起爆主线与起爆器的连接、充电、起爆一系列操作。有效地解决了露天煤矿火区爆破开采中降温困难、爆破器材受高温作用发生燃烧等问题,阻止了因多人作业现场混乱和误操作等原因导致的早爆事故,保障了煤矿火区爆破作业安全,并取得规模爆破的效果,可为类似露天煤矿火区爆破开采提供参考。     

分布式光纤测温技术在火区爆破中应用

为了满足多点测量、响应时间短、精度高以及测温范围广等要求,将分布式光纤测温技术应用到高温火区炮孔测温中。为了适应高温炮孔中温度高、湿度大等复杂条件,采用镀金光纤作为分布式光纤测温系统的测温段。现场试验表明分布式光纤测温系统能快速获得炮孔温度分布情况,通过比较同一炮孔在注水降温前后的温度,结果表明:炮孔温度在注水降温停止后的较短时间内即可回升至降温前的温度,因此现场装药连线等爆区区域内的工作需要在抽出水管后的较短时间内完成。     

煤矿火区中锡箔纸防水袋注水爆破研究与应用

温度一直是制约煤矿高温火区爆破施工的重要因素,为了在相对高温区域进行爆破作业,采用锡箔纸防水袋注水爆破技术。采用该爆破技术方法在高温火区内进行了13组爆破作业,孔深在4~12 m内。结果显示:爆破操作时间能够控制在3 min之内,且装药过程顺畅,虽然存在部分根底,但爆破效果总体上满足对高温火区爆破效果的要求。该方法要求钻孔后,无需注水,采用锡箔纸防水袋下孔注满水后,可防止高温火区注水对孔壁的破坏,确保钻孔后孔壁光滑完整,保证装药操作时间,避免卡孔,保证爆破安全和质量。     

煤矿高温火区爆破技术的研究与应用

针对目前煤矿火区高温爆破技术效率较低的问题,根据爆破器材的耐热温度和炮孔的降温性能,并考虑安全裕度,把火区科学地分为一级温度区等5个温度区。然后根据各个温度区炮孔特点,从测温、降温、爆破器材选择、爆破方法等方面精细研究各自爆破技术,并在火区进行爆破实践。结果表明:由联合使用热电偶和红外测温仪、区别降温时间、安全不可逆联网方式、合理爆破顺序等组成的分区爆破技术可提高目前爆破效率、保障爆破安全、降低爆破成本。     

PVC管注水爆破方法在煤矿火区中的应用?

温度一直是制约煤矿高温火区爆破施工的重要因素,为了在相对高温区域进行爆破作业,采用PVC管注水装药的爆破方法达到预期的爆破施工进度及效果。PVC管注水爆破方法改变原来直接炮孔装药中孔壁与炸药直接接触时热量的传导路线,用PVC管和水将炸药与炮孔隔开,增加隔热层;同时,在PVC管中注水起到了降温作用,延缓了炸药的升温速度,提高了爆破施工作业的安全性及进度。     

露天煤矿火区爆破安全作业技术

为了在保证安全的前提下提高露天煤矿火区爆破施工规模和生产效率,以宁夏汝箕沟煤矿羊齿采区为工程背景,在总结分析常规爆破施工方法存在的主要问题基础上,围绕温度监控、装药方式、施工程序等方面进行了深入研究.提出了采用全孔深测温装置和装药前全过程炮孔温度监控装置,实现了全方位温度监测;采用耐热防护装置,提高了火区爆破的适用范围...     

露天煤矿火区爆破安全作业技术

为了在保证安全的前提下提高露天煤矿火区爆破施工规模和生产效率,以宁夏汝箕沟煤矿羊齿采区为工程背景,在总结分析常规爆破施工方法存在的主要问题基础上,围绕温度监控、装药方式、施工程序等方面进行了深入研究。提出了采用全孔深测温装置和装药前全过程炮孔温度监控装置,实现了全方位温度监测;采用耐热防护装置,提高了火区爆破的适用范围;基于常规施工工艺提出了一套特殊的爆破施工程序,实现了露天煤矿火区快速、安全爆破。实践证明,采用的火区爆破施工技术具有安全可控、施工高效、成本低廉等特点,在类似工程中具有广泛的推广应用价值。     

均温块在热电偶校准中的应用探讨

通过试验数据的比较与分析,阐述了均温块对提高管式炉温场性能、改善铠装廉金属热电偶校准结果准确度方面的显著作用,并对均温块的使用方法进行了探讨。     

Stability of silicon diodes as temperature sensors in the range 4.2 – 273 K

Thermometric properties of TESLA — KA 136 silicon diodes as temperature sensors in the range 1.5 — 380 K are presented. Special attention is paid to the stability of these sensors which was examined for 30 diodes. This stability has been verified both dynamically using a method of cycling the diodes from room temperature to the temperature of liquid helium 100 times and statically using a method of storing the diodes at room temperature for 1 and 2 year periods. It has been found that moe than 90% of the diodes considered have a stability better than 0.4 K and 0.3 K at temperatures 4.2 K and 273 K, respectively, after 30 cycles and 12 months storage.     

Pseudo-Gap Phenomenon in the Sn-Doped Mercury-Based Cuprate Superconductors

The Sn-doped mercury-based copper oxide high temperature superconductors, with nominal composition (Hg_{1 – x} Sn _x )Ba₂Ca₂Cu₃O_{8 +} , have been successfully fabricated. These samples were used to study the pseudo-gap phenomenon in their normal phase. By means of ln[1/(T) – 1/ _N (T)] versus 1/T plots we found three characteristic temperatures T ^*, T _S, and T _F, which describe the role of pseudo-gap phenomenon. From the stated plots, we are able to estimate the magnitude of the pseudo-gap for our samples. The pseudo-gap _PG changes into the spin pairing dipolar superconducting gap _SPDS, when the Fermi kinetic energy shrinks to zero at the critical temperature T _c. It is proved that the spin pairing dipolar superconducting gap , where, _T being the total superconducting gap of the cuprate superconductors, which has the value determined by . It is also proved that the spin pairing dipolar superconducting gap is smaller than the dipolar pseudo-gap, _PG.     

Stability of industrial-grade platinum resistance thermometers in the range 77 – 273 K

The paper pays attention to stability of 10 two-lead industrial-grade 100 Ω platinum resistance thermometers used in the temperature range from 77 to 273 K. The static stability was checked by the method of storing the thermometers for about two years, the dynamic stability was tested by the method of cycling the thermometers in 25 cycles from room temperature to the temperature of liquid nitrogen. it has been found that the static instability of the thermometers ranged within + 2.5 to + 7.7 mK only one thermometer showed –2.5 K The dynamic instability ranged within –5 mK to –80 mK only one thermometer showed +35 mK.     

电站锅炉炉膛温度测量技术发展

该文介绍热电偶测温、CO2红外光谱测温、光纤测温、辐射能测温、声波测温等温度测量方法的原理及其所存在的问题,分析一种基于激光吸收光谱的炉膛测温技术及其系统构成。在某电厂的应用表明,基于激光吸收光谱的测温系统能够对炉膛温度场进行比较精确的测量。测量结果可指导操作人员通过调节相应的二次风门开度等手段来调整锅炉燃烧,使煤粉在炉膛内燃烧均匀,温度场居中分布,从而有效地提高锅炉燃烧效率。     

Measurement of Microkelvin Temperature Differences in a Critical-Point Thermostat

The density of a pure fluid near its critical point is extremely sensitive to temperature gradients. In the absence of gravity, this effect limits the fluid's homogeneity. For example, at 0.6 mK above the critical temperature, the microgravity experiment Critical Viscosity of Xenon (CVX) can allow temperature differences no larger than 0.2 K, corresponding to a gradient of 10^–5 K·m^–1. The CVX thermostat, which consists of a thick-walled copper cell contained within three concentric aluminum shells, was designed to achieve such a small temperature gradient. However, asymmetries not included in the thermostat's model could degrade the thermostat's performance. Therefore we measured the temperature gradient directly with a miniature commercial thermoelectric cooler consisting of 66 semiconductor thermocouples. We checked the results with a half-bridge consisting of two matched thermistors. The measurement was made along a thin-walled stainless-steel cell whose conductance was much lower than that of the copper cell, thus amplifying the temperature differences by a factor of 60. When the thermostat was controlled at a constant temperature, the steel cell's static temperature difference was 5±1 K. (The value inferred for the copper cell is 0.08 K.) Ramping the thermostat's temperature at a rate of 1 × 10^–5 K·s^–1 increased the temperature difference to 0.36 mK. These results demonstrate the feasibility of achieving extremely low temperature gradients.     

超高层筏板基础大体积混凝土温度场分布现场试验研究

通过对某超高层筏板基础大体积混凝土浇筑养护过程进行温度实时监控试验,研究了混凝土水化热温度场在竖向、横向以及不同厚度处的实际分布规律。在基础不同厚度区域9 350 mm、4 500 mm和2 700 mm采取了“下密上疏”和“中密边疏”的监测层位布置方案,利用全自动温度巡检仪实时记录温度变化。结果表明,大体积混凝土最高温出现于竖向方向距离底层向上2 000 mm处左右,横向方向位于散热方式较少的中心处,随着混凝土厚度的增加,混凝土的最高温度也升高。当混凝土开始降温时,混凝土温度下降速率由快到慢依次是顶层、中心层、底层。该结果可为超高层筏板基础大体积混凝土的温度控制及施工养护提供理论参考。     

煤矿火区炮孔温度特性及快速测温方法的研究

针对煤矿火区炮孔测温效率和测温准确性间存在的矛盾,首先分析火区炮孔温度来源,然后在此基础上,通过Ansys热分析软件模拟不同温度来源的炮孔内部温度分布规律,并通过现场钻孔测温验证其准确性,最后结合炮孔温度分布规律,得出快速测温方法。结果表明:热源温度的热传导和裂隙中高温气体的热对流是火区炮孔高温的主要来源。通过粗略测温、观察炮孔等方式,得出炮孔只受热源温度和孔口冷空气影响时,对炮孔下端位置进行重点测温,可提高测温效率,并保障测温准确性。     

Temperature fluctuations in a solid-nitrogen cooled secondary frequency standard

Liquid helium and liquid nitrogen are commonly used as coolants for highly frequency stable oscillators. In this paper, we present the use of solid nitrogen as an alternative coolant. Solid nitrogen solidifies near 52 K under vacuum and we show that the temperature fluctuations in the solid are an order of magnitude lower than in the liquid. This has the advantage of reducing the temperature control requirements necessary to limit temperature induced frequency fluctuations in cryogenic microwave resonator-oscillators.     

现场校准用的测温传感器

介绍了一种新型的现场校准用测温传感器,从温度计的结构和电阻- 温度系数计算方法方面进行论述,并提供相应的试验数据.对温度计的稳定性等方面进行分析,显示该测温传感器的优点,可用于温度产品的现场校准,具有一定的实用价值.