The inner and outer tubes are all leak-detected by helium mass spectrometry. It has good cooling-keeping effect and is easy to install and maintain. It can save a lot of work and installation cost. The product adopts the inner and outer compensation structure of resultant force, the technical index is excellent, the performance is stable, the operation is reliable, the pipeline is treated scientifically, the appearance is beautiful, the surface is smooth, the pipeline service life is long, the anticorrosion is strong; According to the requirement of users, the pipeline can be directly installed vacuum insulation cut-off valve, check valve, emergency shut-off valve, control valve, solenoid valve, gas-liquid separator and so on