CHEMICAL VAPOR DELIVERY SYSTEM AND METHOD FOR CONTROLLING THE FLOW OF VAPOR IN A CHEMICAL VAPOR DELIVERY SYSTEM

摘要

The previous methods of controlling the flow of vapor transported by a carrier gas from a bubbler (10) to a using system have customarily been the thermal-conductivity mass flow meter and the temperature controlled vaporizer bubbler (10). However, such control methods have the disadvantage that fluctuations occur in the vapor mass flow. In accordance with the present invention the flow of vapor transported by a carrier gas from a bubbler (10) to a using system is controlled to provide on uninterrupted uniform mass flow of the vapor to the using system. Control of the flow of vapor is achieved by controlling the temperature (48) and pressure (50) within the bubbler (10).