Low Turbulence Argon Purging System

Abstract

Apparatus and method for purging atmospheric air from a chamber with a gas including means for generating a substantially non-turbulent, laminar flow front of the gas into the chamber with minimal turbulence to displace the atmospheric air in the chamber, the chamber having exhaust means associated therewith to permit the displaced atmospheric air to exit the chamber. The chamber is preferably a welding chamber and the gas is preferably argon.

1 . Apparatus for purging atmospheric air from a chamber with a gas comprising means for generating a substantially non-turbulent, laminar flow front of the gas into the chamber with minimal turbulence to displace the atmospheric air in the chamber, said chamber having exhaust means associated therewith to permit the displaced atmospheric air to exit the chamber. 
     
     
         2 . The apparatus of  claim 1  wherein the means for generating a laminar flow front comprises a perforated plate positioned within the chamber having a plurality of spaced-apart holes formed therethrough, a purge support plate positioned in a spaced relation beneath the perforated plate, said purge support plate having a plurality of spaced-apart diffusers affixed thereto and a manifold means communicating with the diffusers and adapted to supply the gas to the diffusers, whereby the gas is emitted to the diffusers to enter the space between the purge support plate and the perforated plate to pass through the holes in the perforated plate creating a low turbulent, laminar flow front of gas to displace the atmospheric air in the chamber. 
     
     
         3 . The apparatus of  claim 1  in the form of a welding chamber. 
     
     
         4 . A method for purging atmospheric air from a chamber comprising the steps of:
 (a) providing an airtight chamber having exhaust means associated therewith;   (b) providing means for generating a substantially non-turbulent, laminar flow front of a gas into the chamber to displace the atmospheric air in the chamber; and   (c) exhausting the displaced atmospheric air from the chamber through the exhaust means.   
     
     
         5 . The method of  claim 4  wherein the means for generating the substantially non-turbulent, laminar flow front of the gas provided in step (b) comprises the apparatus of  claim 2 . 
     
     
         6 . The method of  claim 5  wherein the chamber is a welding chamber. 
     
     
         7 . A method of welding comprising the steps of:
 (a) providing an airtight weld chamber having exhaust means associated therewith;   (b) providing means for generating a substantially non-turbulent, laminar flow front of an inert gas into the chamber;   (c) conducting an initial purge with the inert gas according to step (b) at a desired flow rate to displace atmospheric air from the chamber and exhausting the displaced atmospheric air from the weld chamber through the exhaust means until an oxygen content in the weld chamber is at a desired level; and   (d) conducting a maintenance purge after step (c) by decreasing the flow rate of inert gas so as to maintain the weld chamber at or below the desired oxygen level during welding.   
     
     
         8 . The method of  claim 7 , including conducting a standby step after conclusion of welding in step (d) by halting the continuous flow of inert gas into the weld chamber, and initiating short bursts of inert gas periodically to maintain a desired gas pressure in the weld chamber. 
     
     
         9 . The method of  claim 7  wherein the desired level of oxygen in the weld chamber is detected by providing a test plate in the weld chamber and depositing a weld bead on the test plate, wherein a shiny weld bead deposited on the test plate indicates an acceptable level of oxygen is present. 
     
     
         10 . The method of  claim 7  wherein the inert gas is argon.