双蓄热式加热炉换向阀应用优化

针对新钢高速棒材生产线双蓄热式加热炉换向阀在使用中出现的侧阀板密封圈损坏、换向阀阀杆与箱体间漏煤气、阀杆变形卡死、换向阀开关不到位、管道内壁的锈蚀物堵塞三联件或是气源管路以及阀杆与阀板的连接方式在设计上存在缺陷等问题,采取了严格控制炉温、定期更换阀杆密封圈、增加隔热材料及优化换向阀结构等措施,减少了换向阀的故障率,提高了换向阀的安全运行可靠性。     

1500m^3／h制氧机自动阀的改造

大连钢厂制氧车间的两台７０年代初自制的ＫＤＯＮ—１５００／１５００制氧机，由于设计和施工等方面的缺陷，该机的故障较多，尤其是自动阀箱里面的自动阀经常损坏而导致设备停止运行。自动阀的主要作用是使进出空分装置的正、反流气体自动分配．当正流空气由３０℃自上而下进入蓄冷器底部时，温度降至-１７２℃污氮由-１７８℃从蓄冷器底部上升至顶部，复热后排出装置。四个自动阀箱分为两组，每组两个自动阀箱中的１６个自动阀每５～６ｍｉｎ切换一次，以保证正反气流的正常分配，从而满足制氧生产工艺要求。而正常生产中自动阀的故障至…     

AWC伺服阀故障浅析

介绍了粗轧伺服液压系统设备组成,阐述了该液压系统AWC伺服阀存在的一些设计缺陷和运行过程中出现的故障,如阀台上阀块设计失误,无法安装伺服阀、AWC控制阀台震动剧烈、频繁漏油等,并提出了相应的解决方法和措施,改进后整个伺服液压系统平稳运行,伺服阀损坏机率大大降低。     

干熄焦汽轮机组抽汽逆止阀故障分析与改造

主要介绍抽汽逆止阀的开闭控制原理,对原水控系统出现的故障原因进行分析,并结合实际提出改造方案,将抽汽逆止阀开启的控制动力由水控系统改为气控系统,消除了故障。     

高压水除鳞喷射阀的改进

对高压水除鳞喷射阀阀杆与控制部分由分体式结构改为整体式，消除了原喷射阀杆经常断裂的缺陷，确保其稳定准确地开关，减少了故障停机时间，节省了检修费用并提高了带钢的表面质量。     

热轧机乳液系统控制蝴蝶阀结构的改造

分析轧板分厂热轧机乳液循环系统蝴蝶阀经常损坏的原因,重新进行强度计算和结构设计。经过近半年多的使用,改进后的乳液蝴蝶阀结构未再发生故障,解决了生产难题。     

水隔离浆体泵清水阀漏油漏水的原因分析及处理措施

本文介绍了的水隔离泵的工作原理,从液控清水阀的作用及结构分析了渗氮阀杆发生电化学腐蚀的机理及清水阀易漏油漏水的原因,并提出了采取改进阀杆表面处理措施--电镀铬,提高阀杆及密封圈的使用寿命,解决清水阀漏油漏水的问题。     

热风阀阀杆镀层失效原因分析

本文就热风阀阀杆电镀层脱落、基体腐蚀问题,通过腐蚀产物SEM形貌分析,认为管道中酸性介质直接导致阀杆基体腐蚀。为预防腐蚀发生,对阀杆电镀层质量提出了严格的技术要求,尤其是电镀层无孔隙要求,采取了相应质量保证措施,解决了电镀层脱落及阀杆腐蚀问题。     

热风炉空气燃烧阀故障原因分析及改造

介绍了热风炉空气燃烧阀的结构、工作原理,详细分析了造成故障的原因以及相应的处理方法,对空气燃烧阀开关过程进行了受力分析及计算,提出液压控制回路的改造方案,改造实施后达到了预期的效果,取得了较好的经济效益。     

KDON-10000/10000-V型切换蝶阀滚键的处理

我厂有三套ＫＤＯＮ－１００００／１００００－Ｖ型空分设备，其切换系统均采用蝶阀，但在运行中经常发生前阀杆滚键故障，处理这种故障均需要整个机组停机，严重影响着公司的生产。我们通过认真分析研究，决定采用在前阀杆与阀柄的配合处穿销钉的方法来解决了这一问题，下面以氮切阀为例，具体处理方式如下：１穿销钉处轴的强度校核ａ．气缸的最大提升力Ｆ动力气源气压：Ｐ＝０．６ＭＰａ气缸直径：Ｄ＝１５ｃｍｂ.提升力Ｆ施加在前阀杆上的扭矩Ｔ提升活塞杆与传动轴的距离ｓ＝１２ｃｍＴ＝Ｆ·ｓ＝１２７１７０Ｎ·ｃｍｃ．穿销钉处轴的…     

空透机滑动轴承故障诊断

本文通过ＢＺ－８７０１袖珍式测振仪和ＦＦＴ动态分析仪配套，采集透平空压机滑动轴承的振动特征信号，用图表和谱图准确地判断出机组的故障部位及损坏程度。     

质量流量控制器在智能吹氩系统中的改进与应用

莱钢质量流量控制器损坏的主要原因是过压击穿损坏和内部电路故障。通过采取质量流量控制器换型、增加切断电磁阀、修改控制软件等措施进行改进,提升了智能吹氩系统的工作稳定性,质量流量控制器损坏率显著降低。     

空分装置冷箱入口V101阀自动开启程序的设置

针对安阳钢铁股份有限公司空分装置的控制系统工艺流程,重点介绍了冷箱入口V101阀自动开启程序和氧透自动加载程序,并对应用情况进行了分析。     

A videofluoroscopic comparison of straw and cup drinking: the potential influence on dental erosion

Tracheostoma valves are often required in the rehabilitation process of speech after total laryngectomy. Patients are thus able to speak without using their hands to close the tracheostoma. The improved Groningen tracheostoma valve consists of a "cough" valve with an integrated ("speech") valve, which closes for phonation. The cough valve opens as the result of pressure produced by the lungs during a cough. The speech valve closes by the airflow produced by the lungs, thus directing air from the lungs into the esophagus at a deliberately chosen moment. An experimental setup with a computer-based acquisition program was developed to measure the pressure at which the cough valve opened and the flow at which the speech valve closed. In addition, the airflow resistance coefficient of the tracheostoma valve was defined and measured with an open speech valve. Both dry air from a cylinder and humid expired air were used. Results showed a pressure range of 1-7 kPa to open the cough valve and a flow range of 1.2-2.7 l/s to close the speech valve. These values were readily attained during speech, while the flow range occurred above values reached in quiet breathing. The device appeared to function well in physiological ranges and was optimally adjustable to an individual setting. No significant differences were measured between air from a cylinder and humid expired air. Findings showed that methods used to obtain results could be employed as a reference method for comparing aerodynamic characteristics of tracheostoma valves.     

大型透平式离心压缩机振动故障分析及处理

针对大型透平离心空压机在试运转中出现的振动故障,进行分析、诊断,判断振动故障的原因,采取相应的措施处理,通过开机运行来验证分析与诊断的准确性。     

大型高炉用ф1700mm新型阀门的制造

本文介绍大型高炉热风炉送风和燃烧系统用，通径为１７００ｍｍ的冷风阀、煤气燃烧阀、煤气切断阀和助燃空气燃烧阀四种新型阀门的性能、结构特点和制造关键技术。特别是堆焊Ｓｔｅｌｌｉｔｅ合金不出裂纹和使用中型组合夹具元件组装大型夹具加工阀体及阀板，保证阀门制造质量的经验。     

分子筛后空气中CO2含量超标故障分析与处理

对天铁空分设备分子筛后空气中CO2含量超标的故障现象进行了分析,经分析确认其原因是分子筛再生流路的阀门QD-305发生了微漏.通过对设备进行停机检修,更换了新的QD-305阀门,检修后分子筛后空气中CO2含量不再超标,设备运行正常稳定.     

汽轮机调节系统故障分析与解决办法

在汽轮机调试过程中,拉阀试验不正常,直接影响了汽轮机空负荷试车。通过查找原因并消除,汽轮机空负荷试车得以正常进行,为机组投运创造了条件。     

氮气循环与空气循环流程的应用与选择

介绍了空气循环与氮气循环流程的空分设备的三种流程形式,通过具体计算详细对比了空气循环单泵流程、空气循环双泵流程和氮气循环单泵流程三者在氮气透平压缩机是否能做、下塔抽氮气量限制等因素的影响下,能耗与投资的优劣势,同时提出了针对产品规格的流程选择。     

Therapy with a combination of low doses of interleukin 12 and chloroquine completely cures blood-stage malaria, prevents severe anemia, and induces immunity to reinfection

PURPOSE: To develop an instrument to measure corneal sensitivity. Mechanical stimulation was performed with increasing air flow. Chemical stimulation consisted of local pH decreases induced by a mixture of air and CO2 at different concentrations. METHODS: Air and 98.5% CO2 were mixed with an electronic, proportional-direction control valve to obtain gas mixtures from 0% to 80% CO2. The regulated outflow of gas was carried to a probe mounted on a slit lamp holder, where it was warmed and its CO2 concentration monitored. An electronic valve directed gas pulses of controlled duration to the cornea. Corneal stimulation was performed in 17 young human subjects. The intensity of the experienced sensation was recorded in a continuous visual analog scale (VAS). To obtain threshold values and intensity-response curves, 3-second pulses were applied. For mechanical stimulation, air pulses of increasing flow were used. For chemical stimulation, gas mixtures of increasing CO2 concentration at subthreshold flow and CO2 in stepped increases of 5% was applied. RESULTS: Mechanical and chemical stimulation of the cornea evoked a brief sensation of irritation. Mechanical threshold (flow values) varied among subjects but were reproducible within each subject and were higher with warmed air. The magnitude of the sensation increased proportionally to the flow of air. The mean chemical stimulation threshold (CO2 concentration) was 25% +/- 3%. Increases in CO2 concentration from 10% to 80% augmented proportionally the intensity of the evoked sensation. CONCLUSIONS: The gas esthesiometer, which combines variable air flow and CO2 concentrations, permits application to the cornea of mechanical stimuli of controlled force and pH reductions of increasing magnitude. This instrument may be useful in a separate exploration of mechanical and chemical sensitivity of the cornea in human subjects.