Baized on moddling calculating the coefficient of performance of refrigeration cycle with two stages compression and volumic refrigerating effect of the compressor while working and the change of high-low pressure volumic ratio, a seres of conclusions have been obtained for the guidance of exploring the reasonable high-low pressure volumic ratio of the two stages compressor and the best wo.

If complemented with the economy device in low-voltage grade, the unit refrigeration amount of mix a group of one pair of spiral shell pole machines under the low-temperature operating mode runs can be improved.

This introduction tells the advantages of fiberglass cloth, time of standard issuing, standard name, product designation and specifications for mass per unit area, combustible matter content, tensile breaking strength, limit for harmful matter and product inspection regulation.