A stuffing box apparatus for sealing between a polish rod in a hydrocarbon production well comprises a tubular housing arranged for connection to the well which has a bore therethrough to receive the polish rod. The hardware interlock system includes an RF generator operative to transmit a forward RF power used to generate plasma in a plasma chamber. The cover includes an aluminum plate having a surface on which an anodic oxidation process is performed. A catalyzer unit is provided before the entrance of the fuelair mixture into the combustion chamber. The cooling channel includes a channel segment which is located near the drain hole and which is formed to have a sectional shape avoiding the drain hole.