共查询到20条相似文献,搜索用时 431 毫秒
1.
IEC79—17(第1版)1990—10爆炸性气体环境用防爆电气设备第17部分:危险区域电气装置的检查和维护标准(煤矿除外)(续)4、附加规定4.1防爆型d─—隔爆外壳(见表1)4.1.1隔爆接合面(见3.4.1条)当重新装配隔爆外壳时,所有接合面应... 相似文献
2.
2.滑动轴承用滑动轴承代替滚动轴承能显著降低轴承噪声。目前一般趋向是在大型或分马力及以下的微型电机中,较多采用滑动轴承。尤其微型电机大多要求低噪声,而轴承噪声常最突出,如采用高精度轴承又太贵。据统计,微型电机用的粉末冶金含油轴承能保证电机轴承噪声不大于40分贝(A),要做到30 相似文献
3.
以茂名热电厂3号汽轮机为例,分析了汽扛接合面产生间隙的原因,介绍了铜网垫片在高压汽轮机汽缸接合面上的应用及其工艺实施过程。实践证明,铜网垫片是消除汽缸接合面间隙、治理接合面泄漏的一种有效而简单可行的方法. 相似文献
4.
电刷镀技术在修复汽缸接合面中的应用江苏省电力局科教处孙卫平多年来,科研部门和火电厂技术人员都在研究如何解决汽缸接合面变形处理的技术及工艺方法。过去曾采用补焊,大面积人工修刮,以及更换汽缸接合面螺栓材质,增加螺栓紧力的办法消除漏气,但效果均不够理想。最... 相似文献
5.
高压多级离心泵接合面密封的好坏,直接关系到泵的安全运行。接合面一旦出现泄漏,不仅损耗给水,脏污运行现场,而且容易导致泄漏处零件材料的冲损。一般虽经更换垫片就可以使用,但严重时就要焊补接合面、车床加工及研磨,这样都要被迫停役,解体检修,给检修工作带来了许多麻烦。 相似文献
6.
针对GB 3836.2标准2000年版(简称“新标准”),从名词术语、外壳材质及强度、专用规定、过盈配合接合面、ⅡC电气设备的接合面、螺纹隔爆接合面、衬垫和O形环、胶粘接合面、透明件、紧固件、电缆和导线的引入及连接、检查与试验等12个方面,与老标准进行了分析比较。 相似文献
7.
提出了防爆电气设备的防护结构及某些具有特殊结构的防爆电气设备所采取的防护型式,分析了衬垫密封时存在的两种问题和注意事项,并对采用止口隔爆接合面、平面隔爆接合面时密封结构的设置位置进行了总结。 相似文献
8.
9.
介绍了滑动轴承九种损伤类型,分析其产生的原因和解决措施。提出了如何通过滑动轴承动态监测技术中的振动测量技术和污染检查来判断滑动轴承工作是否正常。通过监测润滑油质量技术,磁塞检查油的光谱分析技术,铁谱技术,可以提前发现滑动轴承存在问题,应及时处理,以防止滑动轴承不能正常工作。 相似文献
10.
隔爆外壳是由具有一定强度的钢板或铸钢、铸铁、铝合金、不锈钢和塑料等非金属材质制成的机械结构,并具有一定的耐爆能力。然而隔爆外壳的接合面形式是多种多样的,文章简要介绍了隔爆外壳接合面结构形式和隔爆外壳的设计要求。 相似文献
11.
12.
天水长城开关厂研制的ELH1-126/T2500-40型气体绝缘金属封闭开关设备(GIS)采用SF6气体作为绝缘和灭弧介质,由断路器、隔离开关、接地开关、套管或电缆终端等电器元件相互直接连接构成.公司在研制过程中吸收并应用了国际先进的技术和成熟的运行经验,因此产品具有体积小、配置灵活、易于安装、不受外界环境影响、维护简单、不检修周期长等特点.…… 相似文献
13.
Two types of encapsulated lead zirconate titanate (PZT) composite hydrophones have been built and tested: a straight walled 1-3-0 PZT composite design and a curved wall 1-3-0 PZT design. The solid freeform fabrication (SFF) technique was used to construct the polymer encapsulation for the two prototype designs.In the 1-3 composites soft PZT bars are embedded in a polymer matrix with a surrounding air gap. The polymer encapsulations were fabricated on a SFF stereolithography machine in order to enclose the gap and the PZT. Air gaps between the polymer and the PZT were shown to increase the hydrostatic piezoelectric response (d
h) by absorbing the lateral hydrostatic stress. Because of the small percentage of PZT, these composites had a low density (neutral buoyancy), low dielectric constant, and, therefore, a lower dielectric constant, and a corresponding higher hydrostatic voltage coefficient, g
h.The curved-wall composite design decoupled the PZT component more effectively from the lateral pressure, and thereby improved upon the direct piezoelectric effect. The large cap surface and the curved-wall further improved the amplification of the mechanical loading on the PZT element. The effective hydrostatic charge coefficient d
h, reached about 1100 pC/N which amplified the d
33 coefficient, and greatly enhanced the d
h
g
h figure of merit. 相似文献
14.
GB4943-2001是我国信息技术类产品的现行国家标准,它等效采用IEC60950-1:1999。目前IEC60950-1:2005已经代替IEC6095-1:1999。以下为GB4943-2001与IEC60950-1:2005的主要差异。 相似文献
15.
16.
17.
18.
19.
Meijuan Zhou Min Sun Mimi Li Shihui Xie Shifeng Huang 《Journal of Electroceramics》2012,28(2-3):139-143
A design method is presented for 1-3-2 type multi-element piezoelectric composite so as to provide basis for the development and study of transducer and transducer array. The composite samples have been fabricated by a twice dice-filling process from lead zirconate titanate (PZT-4), epoxy resin and silicone, the properties of the composites have been measured and investigated physically. The results show that the piezoelectric, dielectric and electromechanical coupling properties of the composite exhibit a good consistency, while it has a high thickness electromechanical coupling factor K t and a wide bandwidth of pulse-echo signal. The impedance plot of every element indicates good behavior that all elements show excellent frequency consistency, and on the other hand the chance of coupling of lateral resonance and thickness resonance is very small, and with a clear thickness resonance mode at around 100?kHz. Silicon has extremely decoupling properties which can efficiently block the transmission of the acoustic vibrations and eliminate coupling effect among elements. And the farther the distance between the incentive element and receiving element is, the smaller the response signal become, while the response signal decay rate exhibits the trend of increase, the largest up to 95%. 相似文献