This invention relates to a method and system for increasing the utilization of the supply of acetylene from two acetylene sources. The flow is provided at a substantially constant delivery pressure to a point of use, such as a customer point of use. A portable apparatus is configured to operably connect to each of the two acetylene sources simultaneously and during operation automatically provide flow from one of the acetylene sources through various valving and piping assembled onto the portable apparatus followed by supply to a customer point of use.