Stream switching system

An improved double block and double bleed stream switching system (modifiable to, for example, a double block, single bleed stream switching system) includes a common stream path for a multitude of gas streams from, for example, a process pipeline. The improved stream switching system includes a heating mechanism and insulation oven to help temperature stabilization, along with a structure to separate temperature sensitive solenoids from the heated area. Pre-heat coils are located between the sample switching system and the sample shut off system to warm the gas sample and to act as a flow restrictor. A first embodiment is suited for the Division environment and a second embodiment is suited for Division uses. The improved stream switching system may also feature membrane or cartridge filters located upstream of the sample wetted portion of the stream switching system.