This document introduces the use of calibrated helium leak and provides detailed step-by-step instructions
This document provides instructions and technical information for the Varian NW25 Calibrated Helium Leak. The device is designed with an integral helium reservoir and an isolating valve, featuring either an NW25 or a 1-1/8 inch diameter sealing surface to fit the test port of any Varian Leak Detector.
The manual explains the principles of operation, noting that helium permeates through the pyrex-glass finger. It details how leak rates are affected by temperature and depletion over time, providing a table of typical depletion rates for various PIN suffixes. Users are advised to leave the valve open when not in use to maintain stability.
It is furnished with either an NW25 or a 1-1/8 inch diameter sealing surface to fit the test port of any Varian Leak Detector.
When the calibrated leak is not in use, it should always be left with the valve open and stored at the same temperature at which it will be used.
The actual leak rate increases with increased temperature at 3% per degree (Celcius).