System for preventing contaminants from reaching a gas purifier

A continuous ultra-high gas purification supply apparatus, comprising:

• a back-up conventional purity gas supply unit;
• a gas purifier disposed downstream of the back-up conventional purity gas supply unit, the purifier configured to remove hydrogen, oxygen and carbon monoxide to produce a continuous stream of ultra-high purity gas;
• and
• a buffer vessel disposed upstream of the purifier, the buffer vessel sized to hold up a predetermined volume of a conventional purity gas stream prior to routing the conventional purity gas stream to the gas purifier, whereby if a contaminant concentration of the hydrogen, oxygen and carbon monoxide in the conventional purity gas stream each exceeds a predetermined level as determined by a gas analyzer disposed upstream of the buffer vessel, the buffer vessel is configured to switch from on-line to off-line to prevent the contaminated conventional purity gas stream in the buffer vessel from reaching the gas purifier, and the back-up conventional purity gas stream is configured to switch from off-line to on-line to provide a back-up supply of conventional purity gas into the gas purifier.