Orifice leak inlet

Fig. 5.2 Schematics of the atmospheric pressure orifice leak inlet system attached to the lithium ion attachment mass spectrometer. The sampling of the inlet probe is shown for polymer pyrolysis. RC reaction chamber, ELS electrostatic lens system, QMS quadrupole mass spectrometer. (Reprinted with permission from [26]. 2001, Elsevier)...

The gas pressure in the first hexapole section is influenced by gas leaking in from the inlet system and, at about 10" mbar, is higher than desirable if excessive ion/neutral collisions are to be prevented. Therefore, the first hexapole is separated from the second hexapole section by a small orifice, which allows ions to pass through. 

In Jan 93 when SG was put in service for the first time, after 70 h of operation at 4 MWt, a water leak took place due to a linear pin hole defect in die end cap of one of the orifice assemblies at SG inlet. All similar caps (35 numbers) were ultrasonically inspected and four more were found having indication of linear defects. The leaking cap was replaced and additional covers were welded on the defective caps and SG modules requalified (Fig 6). This was attributed to inspection (having less capability to detect such defects) before accepting the material for fabrication of these caps. 

Steam Leaks from Steam Pipes (Visible) The most common causes of steam leaks come from holes in steam pipes and threaded pipe connections in a steam and condensate system. Steam flow through a leak can be calculated using an orihce equation, which is based on the diameter of the leak, pressure at the inlet of the orifice, and pressure at the outlet (atmosphere). 

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