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计量喷嘴常有于测定粗真空泵的气体流量的装置,从理论和实践这两方面对计量喷嘴的工作原理,计算方法,安装及使用要求等问题作了简要的叙述,同时对其测量重复性也作了相应的介绍。 相似文献
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一、装置的组成 临界流喷嘴气体流量标准装置(以下简称"装置")主要由气源系统、喷嘴计量段、被检表检定段及微机控制采集系统等组成.如图1所示.其工艺流程为:通过气源系统的空气压缩机组(或真空泵组)结合稳压容器(或缓冲容器)以及大气,作为装置的稳定气源.在计算机上按照检定流量计的需要,通过操作喷嘴开关阀门,实现喷嘴组合流量的选择与切换. 相似文献
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真空泵抽速测量有多种方法,其准确度受到方法、仪表精度等影响。其中定流量法作为其中一种方式,其建立在一元可压缩流体理论基础上。文章结合一元可压缩流体基础理论与现有测试方法,提出将喷嘴临界状态作为定流量法测量基础。通过喷嘴临界状态的出现以及临界值计算,作为真空泵流量的测量方法基准数值,测量过程中只需要测定环境参数就可以测定真空泵流量,进而计算真空泵在某规定压力下的抽速。该测量方法装置和过程简单,容易操作,外界因素影响自然降低到最低,是一种可靠、绿色测量方法。抽速作为真空泵最重要参量,数字化、智能化测量是发展方向,准确的抽速测定是真空泵及系统优化的依据,将推动真空技术发展。 相似文献
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介绍了用一种新思路建造的以文丘里音速喷嘴为传递标准的标准表法气体标准装置,一天内温度变化小于0.3℃,真空泵运行能耗大大低于目前水环真空泵和气环真空泵的水平。达到了高稳定低能耗的目的。 相似文献
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我公司蒸汽一级计量由两部分组成:即动力厂锅炉在定压下加热产生的过热蒸汽和炼钢厂转炉、型钢厂加热炉所产生的余热蒸汽。过热蒸汽都采用标准喷嘴作节流元件,它具有压损小(与孔板比较)、耐磨损、流出系数稳定、使用寿命长、结构已标准化、已有丰富使用经验等优点,缺点是加工制作较孔板难度大,成本比用孔板高。余热蒸汽大多用标准孔板作节流件,与标准喷嘴相比,它压损较大,但其加工容易,成本相对低一些。采用标准喷嘴作节流元件的一级计量情况较好,二级计量绝大多数采用标准孔板计量,问题较多。由于各种原因,以前二级量与总量间输… 相似文献
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浙江真空设备集团有限公司近一年来 ,针对医药、化工、冶金、电力、航空航天、石油等各行业的快速发展 ,对罗茨真空泵、滑阀真空泵、水环真空泵作了较大改进 ,同时开发了大型罗茨真空泵、大中型 L Q系列气冷罗茨真空泵机组、SK- A系列高效、高真空单级液环真空泵等一系列新产品。为使广大用户更好地了解公司的产品 ,及更多地收集不同行业的使用要求 ,浙江真空设备集团有限公司于 2 0 0 2年 11月 14~ 16日在贵州省贵阳市召开了 2 0 0 2年度老产品改进及新产品发布交流会。到会客户来自全国各地各行业。会上公司董事长兼总经理王西龙介绍了… 相似文献
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The primary fluid in a steam-jet vacuum pump is not assumed as a perfect gas as general research in the present study. A mathematic model based on the wet steam model for transonic flow is proposed to investigate the flow behaviours of primary fluid in the nozzle of a steam-jet vacuum pump. The simulation based on a wet steam model was carried out to predict the flow characteristics of primary fluid along the nozzle axis by a commercial computational fluid dynamics (CFD) code (FLUENT6.3). The simulation results showed that there was spontaneous condensation as the supersonic flow passing through the nozzle and the simulation results had a good agreement with the experimental data. It is found from the numerical simulation results that the steam flow characteristics in nozzle are quite different from a wet steam model and a perfect gas assumption: the outlet pressure of the nozzle predicted in the present study is higher than that as the primary fluid assumed as perfect gas, the outlet velocity is about 10% lower than that as the primary fluid assumed as a perfect gas, and the temperature at the outlet of the nozzle is much higher than that as the primary fluid assumed as a perfect gas. The simulation results demonstrate that the thermo-positive process due to steam condensation would hinder the supersonic expanding flow process in nozzle and depress the efficiency of the nozzle which would affect the pumping performance of steam-jet pump. 相似文献
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真空系统是真空镀膜设备的主要组成部分,其主泵的选择对真空性能影响很大,真空镀膜设备的发展要求真空性能清洁无油,动态抽速大.传统的以油扩散泵为主泵的设备不能满足要求,本文叙述了油扩散泵、分子泵及低温泵的特点及北京北仪创新真空技术有限责任公司开发以分子泵及低温泵为真空系统主泵的镀膜设备情况. 相似文献
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给出了以真空泵抽速特性系数表示的抽速计算公式,以实例说明如何求值和选定真空泵抽速特性系数,最后说明真空泵抽速特性系数应用。 相似文献
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随着炼钢技术的飞速发展,真空脱气处理技术成为减少钢中气体和非金属杂质的有效措施,其关键在于如何获得真空.本文以某厂利用蒸汽喷射泵的钢水炉外真空处理为例,介绍了真空系统的设备组成,阐述了真空泵的抽气理论,利用边试验边改进的方法来优化蒸汽喷射泵的抽气性能.最后,给出了钢水的真空脱气处理工艺及其效果. 相似文献
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In the case of a plasma-enhanced chemical vapor deposition, large amounts of byproduct particles arrive at a vacuum pump in spite of the use of cleaning process. As these particles are accumulated on internal components of a vacuum pump, its performance is reduced. A plasma reactor located right before a vacuum pump is proposed with an aim to reduce the size and quantity of byproduct particles, thereby to improve the durability of a vacuum pump. The plasma reactor and electrode all have a concentric cylindrical shape, which allows the device to be easily connected to pre-existing vacuum pipelines without any disturbance to the exhaust stream. The sizes of byproduct particles before the vacuum pump are quite diverse in the range of tens of nanometers to tens of micrometers. The plasma reactor makes the size and quantity of byproduct particles much smaller, and the particles larger than 1 μm are not observed anymore. This result indicates that the vacuum pump durability can be significantly improved by using plasmas. 相似文献
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描述了上海天文台在2008年为提高被动型氢原子钟真空系统的可靠性所研制的由非蒸散型吸气剂泵和小离子泵组成的复合泵的实验过程,吸气剂泵在室温下吸收2.1MPa.l的H2气后仍可达到3.2×10-5Pa的真空度,2l/s的离子泵电流工作在0.30μA,证明了复合泵可以维持氢钟13年以上的正常工作。经过再激活固定了激活工艺,吸气剂最终吸氢6.0 MPa.l仍没有饱和,证明了吸气剂的强大吸氢能力。至今复合泵已成功应用在4台被动型氢钟上。 相似文献
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The modern diaphragm pump has become a proven device for generating coarse and fine vacuum. The article describes disigns and functions of various construction types as well as state-of-the art development and manufacturing. Physical and technical demands have resulted in diaphragm pumps with typical ultimate pressures of 70 to 0,1 mbar and a pumping speed of several m3/h. As an almost chemically resistant pump, the diaphragm pump is used in the chemical laboratory. Combining a diaphragm pump with an oil-free, not against atmosphere compressing pump, a contamination-free pump assembly for (ultra-)high vacuum is obtained which is well suited for coating technology, vacuum metallurgy and semiconductor industry due to its oilfree operation. 相似文献