The use of high-speed rotation of the impeller to pass the momentum to the gas molecules, the gas generated directional flow of the vacuum pump. Turbo molecular pump has the advantages of fast start-up, anti-radiation, resistance to atmospheric impact, no gas storage and desorption, no oil vapor pollution or little pollution, to obtain a clean ultra-high vacuum. Turbomolecular pumps are widely used in high energy accelerators, controlled thermonuclear reactors, heavy particle accelerators and advanced electronics manufacturing.
Structure and working principle 1958, the Federal Republic of Germany for the first time put forward the practical Baker turbocharger turbomolecular pump, have appeared after the various structures of the molecular pump, there are two vertical and horizontal, Figure 1 is vertical Turbo molecular pump structure. Turbomolecular pump mainly by the pump body, with a rotor blades (ie moving impeller), static impeller and drive system and other components. The linear velocity of the outer edge of the moving impeller is up to the speed of thermal movement of gas molecules (usually 150 to 400 m / s). The compression ratio of a single impeller is very small, turbomolecular pump to be composed of more than a dozen impeller and impeller. Moving impeller and static impeller alternately arranged. Dynamic and static impeller geometrical dimensions are basically the same, but the blade inclination angle is opposite. Figure 2 for the 20 rotor impeller monolithic rotor. Install a static impeller between each two moving impellers. The outer edge of the impeller is fixed by a ring and the gap between the impeller and the impeller is maintained at about 1 mm. The movable impeller can rotate freely between the impellers.
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Figure 3 for a moving blade schematic. Gas molecules on both sides of the blade are diffusely scattered. On the left side of the impeller (Figure 3a), the gas molecules reflected in angle α1 return to the left when the gas molecules reach the point A; the gas molecules reflected in angle β1 return to the left and the other part passes through the leaves Reaches the right; the gas molecules reflected in angle γ1 will pass directly through the leaves to the right. Similarly, on the right side of the impeller (Figure 3b), when the gas molecules are incident on the vicinity of point B, the gas molecules reflected in the angle α2 will return to the right side; part of the gas molecules reflected in the angle β2 will reach the left side and the other part Returns to the right; the gas molecules reflected in the [gamma] 2 angle pass through the leaf to the left. Tilting the movement of the blades moves the gas molecules from the left through the leaves to the right, much more likely than the right through the leaves to the left. Continuous rotation of the impeller, the gas molecules will continue to flow from the left to the right, resulting in pumping effect.
Performance and Features The ratio of pump discharge pressure to intake pressure is called compression ratio. Compression ratio in addition to the pump level and speed related, but also with the type of gas. High molecular weight gas has a high compression ratio. Compression ratio to nitrogen (or air) is 108 to 109; for hydrogen is from 102 to 104; for large molecular weight gases such as oil vapor is greater than 1010. The pump's ultimate pressure is 10-9 Pa and the working pressure range is 10-1-10-8 Pa. The pumping rate is tens to thousands of liters per second (1 liter = 10-3 m3). Turbomolecular pumps must demonstrate their superiority in the molecular flow regime (the mean free path of the gas molecules is much greater than the maximum size of the duct cross-section) and therefore require that the working pressure be 1 to 10-2 Pa Vacuum pump. Molecular pump itself by the speed of 10000 ~ 60000 rev / min IF motor direct drive.
Measuring Wheel is also known as measure wheel.There are two types, mechanical and digital display measuring wheel. It is designed for outdoor distance measurement. It can be for a variety of ground conditions, including hills, meadows, and rugged construction sites and so on.
Features:
1. Accurate
2. Flexible and durable
3. Easy to operate
4. Light weight and easy to convenient
5. OEM is welcome
6.It is easy to use,great for real estate pros,appraisers,surveyors,law enforcement,facility engineers,flooring specialists,insurance agents,adjusters,decorators,painters,roofers.
Distance Measuring Wheel specification:
Distance Measuring Wheel
Distance Measuring Wheel,Measuring Wheel,Rolling Distance Measuring Wheel,Wheel Measuring Tool
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