Degassing process for titanium sublimation pump filament

A technology of titanium sublimation pump and filament, applied in pump, liquid variable capacity machinery, machine/engine, etc., can solve the problems of incomplete degassing, poor vacuum, and shortening the service life of titanium wire.

Inactive Publication Date: 2007-02-28
INST OF MODERN PHYSICS CHINESE ACADEMY OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the actual working condition of the existing technology is to use a titanium sublimation pump to carry out vacuum pumping operations, and its effect is extremely unsatisfactory. The expected vacuum degree, even the vacuum degree is worse than that of the titanium sublimation pump before sublimation
This is one of the main reasons why the application of titanium sublimation pumps is limited at this stage. Even many domestic units believe that titanium sublimation pumps are not suitable for working in high vacuum systems.
On the other hand, when the titanium wire is pretreated with a large current, the service life of the titanium wire is seriously reduced because the titanium wire is sublimated in the non-working state

Method used

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Examples

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Embodiment Construction

[0010] An example of the present invention is provided below.

[0011] The sublimator used in this embodiment consists of 3 titanium filaments and a heater (only 1 titanium filament is used, and the remaining 2 are spare parts, but all 3 should be degassed). The titanium filament is an argon-free titanium-molybdenum alloy wire (85% titanium, 15% molybdenum) produced by American VACOM Company, with a diameter of 2.1 mm and a length of 141 mm. The rated sublimation current is 48A, the corresponding voltage is 5.3V, and the surface temperature of the filament is 1470°C (1743K) when the rated current is added to produce complete sublimation. Relevant tests show that the critical sublimation current of this material is 28 amperes, so it is determined that the degassing current of this embodiment is 27A, and the corresponding voltage is 3.5V. After calculation, the surface temperature of the filament is 1094°C (1367K), and the degassing is carried out. 24 hours.

[0012] In this e...

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PUM

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Abstract

The invention relates to a pretreatment on titanium wire, wherein said method comprises: before normal operation of titanium sublimation pump, first, adding degassing current on the titanium wire; said degassing current is from 1 / 2 of normal sublimation current to the difference between sublimation current and the ampere, while the degassing time is not less than 24 hours. The invention can fully discharge the gas on the surface of titanium wire and the gas inside the titanium wire, to be discharged outside the vacuum system via turbine molecule pump, to reduce the gas load on the surface of titanium wire most; therefore, when the pump operates normally that after the sublimation of titanium wire, the system can reach vacuum degree. And the best degassing current is 56% of normal titanium sublimation current.

Description

technical field [0001] The invention relates to a method for using a vacuum pump, in particular to a pretreatment method for titanium wires before a titanium sublimation pump works normally, that is, before it is fully sublimated. Background technique [0002] Titanium sublimation pump has a long history as a kind of ultra-high vacuum pump, but it is not widely used in vacuum systems at present, especially in domestic seldom use of such equipment for vacuuming operations. At this stage, there is basically no degassing operation for the titanium filament before using the titanium sublimation pump. Before vacuuming with a titanium sublimation pump, some users apply a small current or a large current (generally close to the full sublimation current) to the titanium wire for degassing treatment for several minutes or more than ten minutes, and then make the pump work sublimation. However, the actual working condition of the existing technology is to use a titanium sublimation p...

Claims

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Application Information

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IPC IPC(8): F04B37/14
Inventor 蒙峻杨晓天张军辉张喜平胡振军侯生军郝斌干
Owner INST OF MODERN PHYSICS CHINESE ACADEMY OF SCI
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