Long-term supply tankers tank cylinder vacuum portable devices Pre-seeking speed

With the development of cryogenic insulation storage industry matures, the study of the influence of storage and transportation of cryogenic insulation also flourished together. The main points accumulation cryogenic insulation insulation, vacuum powder (fiber) insulation, high vacuum multilayer insulation and high-vacuum thermal insulation in the form of several multi-screen insulation. Including high vacuum multilayer insulation due to good insulation properties, the process is simple to obtain the favor, widely used in small-scale low-temperature insulated container, even low tankers and other fields, and has a tendency to gradually expand the application fields. In the many factors that affect the performance of the multilayer insulation, the vacuum has played a crucial role. Research shows that when the degree of vacuum is low ie P> 10 Pa, the vacuum degree change had little effect on the thermal conductivity; when the vacuum degree of 10 - 10 - 2 Pa interval, with increasing degree of vacuum, rapid thermal conductivity fall; when the vacuum better than 10 - When 3 Pa, the thermal conductivity approaching a constant value [1]. Thus, the apparent vacuum of general dissection superior to 10 - 2 Pa, multilayer insulation in order to give full play to the effect, to achieve good insulation purpose now mainstream market vacuum pumping on portable devices have two pumps molecular diffusion pump shown in FIG. First, let me introduce the next bulk diffusion pump pump principle. Diffusion pump oil is heated in a vacuum to a boiling temperature (about 200 degrees) to produce a lot of oil vapors, oil vapor through the draft tube by the directional high-speed spray nozzle levels. Since the diffusion pump intake has been pumping gas near the mouth of the partial pressure is higher than the partial pressure of the vapor stream of the gas. Thus, high-speed movement was pumping gas molecules along the direction of steam, gas molecules hit the wall and reflected pump, and then subjected to vapor flow impact to the pump vapor stream along the wall and re-direction. After several collisions, the gas molecules are compressed to a low vacuum side, and then into the nozzle at several stages of a multistage vapor compression air, and finally pulled out by the pre-pump and the oil vapor is condensed in a cooling pump wall and then return to the lower back is heated, so the cycle of work to achieve the pumping purposes. This represents a selective diffusion pumps must always be equipped with a chiller to cool the diffusion pump, which greatly increased the volume of the complete equipment extremely difficult to carry, and a diffusion pump boot off time is very long, so it is consumed time. It works. Fixed line speed impeller tip speeds up to thermal motion of gas molecules (typically 150 to 400 m / sec). Single stage compression ratio is small, turbo-molecular pump impeller and static impeller to move consists of more than a dozen. Dynamic and static impeller impeller arranged alternately. Dynamic and static impeller geometry is basically the same, but the blade pitch angle opposite. 20 move integrally formed impeller rotor. Between each two rotor vanes mounted a static impeller. Static impeller tip with fixed and movable ring, maintain the gap between impeller quiet about 1 mm, impeller rotatably movable between static impeller. It is a schematic view of a rotor blade work. Gas molecules in motion on both sides of the blade was diffuse scattering. At the left side of the impeller, when gas molecules reach the vicinity of the point A, the gas molecules within the angles α1 reflected back to the left; the gas molecules in the angle β1 is reflected back to the left part, the other part to reach the right side through the blade; gas molecules within the angles γ1 reflection will directly reach the right side through the blade. Similarly, on the right side of the impeller, moving page piece works, when the gas molecules near the incident to point B, the gas molecules in the reflection angle α2 will return on the right; the gas molecules in the β2 reach the left angle of the reflecting part Another part of the return to the right side; the gas molecules in the γ2 reflected through the blade angle to reach the left. Tilt blade motion of the gas molecules to reach the right side through the blade from the left, from the right side through the blade than the chance to reach a much larger on the left side. Continuous rotation of the impeller, the gas molecules will continue to flow from the left side of the right side, resulting in pumping action. So it is not wanted molecular pump cooling, switch time is greatly shortened, with respect to the terms of the diffusion pump if this saves time with space. Both devices are introduced over who are interested are welcome to call