Means for electrically heating gases

In gas heating means for electrically heating gases having

• (a) a plasma generator comprising first and second cylindrical electrodes, said first cylindrical electrode having an open end and a closed end and said second cylindrical electrode having two open ends;
• and
• (b) supply means to supply gas to be heated, said gas generally flowing in a main direction from said first electrode toward said second electrode, the improvement comprising:
• at least one spacer arranged between said first and second electrodes, said spacer defining a length disposed between said first and second electrodes and said length being 100 to 500 mm;
• and
• a first gas supply gap, between said first electrode and an adjacent spacer, for causing the gas to flow initially in a direction opposite to said main direction of gas flow through said gas heating means, whereby an arc may emerge from said first electrode at an upstream arc root, follow an arc passage through said spacer, and contact said second electrode at a downstream root, and whereby said upstream root of the arc is moved against the main direction of gas flow, toward the closed electrode end.