Abstract: A directional control valve having three positions controls the direction of flow through an asphalt distributor. The directional control valve is interposed between a pump and a feed line assembly to a spray bar. The directional control valve has a first position in which flow is recirculated through the pump, a second position in which flow is delivered to the spray bar and a third position providing for handspray and transfer operations. A pressure relief valve is provided for controlling return flow of asphalt from the spray bar to the tank. The pressure relief valve is open in spray bar circulation mode and is closed during a spraying mode. According to the preferred embodiment the directional valve and pressure relief valve are contained within a modular control valve assembly. The directional control valve eliminates the need to reverse the flow in one of the individual feed lines and feed line assembly connecting the modular control valve assembly to the spray bar.

Abstract: A feed line assembly includes adjacent running or coaxial delivery and return conduits for transferring asphalt between a spray bar and a pump and tank of an asphalt distributor. The coaxial feed line assembly provides for one directional flow in each of the feed lines between the spray bar and the asphalt tank/pump. The circulating system can be operated in spraying and circulating modes. Asphalt flows through the delivery conduit to the spray bar and out through nozzles in the spraying mode and asphalt flows from the delivery conduit through the spray bar and is returned through the return conduit in the circulation mode. Asphalt is substantially static in the return conduit during the circulation mode. The coaxial feed line assembly serves as a heat exchanger to transfer heat from the delivery conduit to the return conduit and thereby prevent freezing of substantially static asphalt in the return conduit during spraying mode.

Abstract: In an asphalt distributor having a tank for holding asphalt and a pump for pumping asphalt from the tank to a spraybar, a self draining asphalt strainer is provided. The asphalt strainer includes a body having an inlet and outlet with a filtering chamber disposed between the inlet and the outlet. A filter or straining element is disposed in the filtering chamber for filtering asphalt flowing between the inlet and the outlet. A conduit extends the inlet into the filtering chamber. A pair of valves are disposed on each end of the conduit forming a suckback chamber therebetween. A suckback tube is connected to the conduit intermediate the valves and extends into the filtering chamber. The pump is bidirectional and has a reverse mode which forces asphalt back through the outlet and inlet into the tank. The strainer has a first flow passage from the outlet to the inlet through both of the valves when open.