The invention includes an apparatus and process for the catalytic production of HCN from a feed gas of ammonia and a hydrocarbon gas by means of heat tubes supplying heat to the feed gas stream and heat tubes for removal of heat from the products. The helix cup has a convergent funnel wall. Since the home-in operation is performed only when power is initially supplied, the number of home-in operations is minimized. The fourth input transistor has a gate and a source coupled to a second reference voltage and the second tail current source, respectively. Each individual label includes an attachment end with active adhesive and a freeunattached end with inactive adhesive.