隔膜式压缩机双函数构造膜腔曲面

膜腔曲面形状是隔膜式压缩机的关键,它直接影响压缩机的排气量和膜片使用寿命。多年来,国内外一直沿用一种单指数方程曲面。这种曲面,不但工作容积小,还使膜片的工作应力很不均匀,其外缘应力幅大,膜片的寿命很低,一般不超过1000小时。本文根据压缩机的工作过程,应用对称圆薄板大挠度理论,计算分析了膜腔曲面形状对膜片应力状态和工作容积的影响规律,提出了一种新的膜腔曲面的构造方法,即用双函数组合构造膜腔曲面。经计算表明,新曲面不但使膜片工作应力均匀,外缘应力幅小,同时还增大了膜腔曲面约6.6％,故新构造的曲面对提高隔膜式压缩机的可靠性和经济性具有重要的实用意义。

DESIGN OF DIAPHRAGM CHAMBER CURVE SURFACE SHAPE WITH DOUBLE FUNCTION OF A DIAPHRAGM COMPRESSOR

The design of the curve surface shape of a diaphragm chamber is a key technique. It directly influences the displacement of a diaphragm compressor and the working life of diaphragm. Over the past years, a kind of index curve shape has been used, however, not only is its working volume smaller, but the resulting working stress is also very uneven; in addition, its outer-circumferential ampli- tude is very large, and the life of diaphragm is very shortusually under 1 000 hours. In accordance with the working process of the compressor, this paper pre- sents a new approach to design the diaphragm chamber surface shape by calcula- ting and analyzing the regular influence of the shape of diaphragm chamber curve surface on the stress of diaphragm and the working volume with the aid of large -deflection theory of a thin circular plate, that is, the diaphragm chamber curve shape is designed with the combination double function. Both the calculations and the experiments show that this kind of curve surface not only results in the uniformity of working stress and small amplitude of the outer-circumferen- tial stress, but also enlarges the working volume of the diaphragm chamber by about 6.6%. Hence the new approach of designing diaphragm chamber surface is of practical importance to enhancing the roliability and economy of a diaphragm compressor.