entrance of each dye conduit formed by dye groove 28 the second flow stream the bypass stream flows from the exit of each dye supply conduit 20 to the entrance of each dye bypass drain hole 33 in the undesirable event that a solid contaminant lodges itself at the entrance to a dye conduit formed by dye groove 28 thus restricting dye flow through that groove 28 it can easily be pushed away from the groove entrance and out of the supply stream and into the bypass stream by inserting a properly sized wire into the conduit from the orifice 181 the solid contaminant would then exit the trough 18 by way of dye bypass drain hole 33 through the dye return conduit 34 and into the recirculation system see fig1 where it will be removed through filtration the pressurized air source is connected to air supply fittings 14 when air flow is desired air can flow in a continuous path from the ultimate source of pressurized air not shown through station air supply manifold 177 fig4 and 6 and an associated electromechanical air valve indicated at 159 fig6 to air lines 161 air supply fittings 14 air supply channels 10 and out through air orifices 12 the operation of a.