Abstract: A drum mixer asphalt plant is provided with a rotatable cylinder 10 in which virgin aggregate, recycle material and liquid asphalt are mixed to produce an asphaltic composition and the hot gas stream for heating and drying the materials flow in countercurrent relation. In a first zone within the cylinder 10, aggregates are heated and dried by heat radiation and a hot gas stream generated at a burner head 46 of a combustion assembly 40. In a second zone within the drum cylinder 10 isolated from the burner flame and hot gas stream by the combustion assembly 40, liquid asphalt is sprayed from an injection tube 76 to mix with aggregate materials. A recycle feed assembly 60 delivers recycle asphalt material to the second zone also for mixing with the aggregate and liquid asphalt.

Abstract: A housing for an industrial baghouse constructed of a plurality of panels having a stiffening element integral with the wall. Each panel is similarily constructed in the shape of an elongated "U". The panels are arranged upright in juxtaposition to, and in an alternating manner with, each adjoining panel. A channel is formed between two adjoining panels by overlapping the ends of each panel with the next adjoining panel. This channel creates a stiffening element to give structural rigidity to the housing wall. A housing wall so constructed can withstand the internal pressure associated with a baghouse.

Abstract: A drum mixer asphalt plant is provided with a rotatable cylinder having an internal passageway where the aggregates and asphalt are mixed to produce an asphaltic composition. In a first zone within the mixer, aggregates are heated and dried by heat radiation and the stream of hot gases produced by a burner flame. In a second zone within the mixer, liquid asphalt is mixed with the aggregates. An exhaust tube is disposed within the passageway and extends from the output end of the drum mixer into the first zone to remove the hot gases to prevent degradation of the asphalt. Thus, the second zone wherein the liquid asphalt is mixed with the aggregate is isolated from the hot gases used for heating and drying. Recycle asphalt material may be added in both the first and second zones of the mixer drum.

Abstract: A drum mixer asphalt plant is provided with a rotatable cylinder 10 in which virgin aggregate, recycle material and liquid asphalt are mixed to produce an asphaltic composition and the hot gas stream for heating and drying the materials flow in countercurrent relation. In a first zone within the cylinder 10, aggregates are heated and dried by heat radiation and a hot gas stream generated at a burner head 46 of a combustion assembly 40. In a second zone within the drum cylinder 10 isolated from the burner flame and hot gas stream by the combustion assembly 40, liquid asphalt is sprayed from an injection tube 76 to mix with aggregate materials. A recycle feed assembly 60 delivers recycle asphalt material to the second zone also for mixing with the aggregate and liquid asphalt.

Abstract: For an inside to outside dust collector, a tensioning device for bag filters for connecting the upper end of a fabric sleeve filter to an overhead support. The device includes a modified double draw bar spring assembly having a conical spring therein interposed between the overhead support of the baghouse and the upper end of the bag filter. A retainer member engaging the large end of the conical spring receives therethrough the first and second draw bars to prevent binding of the spring assembly and to translate the conical spring force to uniform linear forces acting through the first and second draw bars to appropriately tension the filter sleeve and to permit controlled flexure during cycling from a filtering to a cleaning operation.

Abstract: Installation and maintenance equipment to tension a fabric sleeve filter supported from a bag support frame in a baghouse by a retainer rod and a tensioning spring. A tensioning tool is configured to be removably coupled to the retainer rod while compressing the tensioning spring to pull taut the fabric sleeve. A speed control regulates the speed at which the spring is compressed and a regulator determines the force applied to the spring. A pneumatic, hydraulic or electromechanical power source supplies the tensioning force.

Abstract: Installation and maintenance equipment to tension a fabric sleeve filter supported from a bag support frame in a baghouse by a retainer rod and a tensioning spring. A pneumatic tool is configured to be removably coupled to the retainer rod while compressing the tensioning spring to pull taut the fabric sleeve. A flow control valve regulates the speed at which the spring is compressed and a pressure regulator determines the force applied to the spring.

Abstract: An industrial baghouse having a single clean air plenum in which a portion of the filter bags can be serviced while the baghouse remains on line. Service compartments in the clean air plenum can be individually isolated from the remainder of the clean air plenum by installing removable slide gates through normally sealed slots formed in the top of the baghouse. When a service compartment has been enclosed by the gates, it is isolated from the clean air plenum and access doors above the compartment can be removed to provide access for on line inspection and servicing of the filter bags and related components. Removable gaskets which normally seal the slots can be removed prior to insertion of the gates and replaced following removal of the gates.

Abstract: For an inside to outside dust collector, a self tensioning bag retainer for connecting the upper end of a fabric sleeve filter to an overhead support. For preinstallation of the filter assembly, a compressed tensioning spring is retained from movement by a pin member to facilitate ease of installation. With the pin member removed, however, the spring acts upwardly against a retainer cap to appropriately tension the sleeve filter and to permit controlled flexure during cycling from a filtering to a cleaning operation.

Abstract: A method and apparatus for use in an outside collection baghouse to identify defective filter bags. Each filter bag is equipped with a sensing head adjacent the open mouth of the bag. Each sensing head includes a pair of optical fibers having free ends disposed in the path of gas flowing out the bag mouth. Light is applied to one optical fiber in each pair and the amount of light reaching the other optical fiber is sensed to provide a measurement of the amount of light intercepted by particulate matter leaking through the bag.

Abstract: A 24-hour operable baghouse plant with on-line maintenance features. The filter cartridge, comprising a tube sheet and a plurality of vertically suspended filters, includes a skeletal framework and a plurality of retaining bars traversing the bottoms of the filters to receive a stud projecting from the end cap of each filter. The tube sheet is equipped with retractable locking bars which cooperate with guide and support members attached to the housing walls to wedge the tube sheet to sealing engagement with the housing.

Abstract: Prior to initiating cleaning of the filter assemblies with high pressure air, process gas flow is restricted, as with a flow control valve, to establish a pressure drop across the baghouse in the range 1/4 to 1/2 inches water gauge.

Abstract: A disposable filter cartridge for suspension from the tube sheet in a baghouse. A wire mesh cylindrical cage is rigidly fitted with a diffuser having plurality of flexible fingers which sealingly encircle the tube sheet collar. A fabric filter sleeve encases the cage and has an upper seal skirt of greater diameter than the outside diameter of the diffuser. The cage may be equipped with a bottom end cap having an annular groove adjacent the cage to facilitate crimping thereon. The bottom of an open filter sleeve may be provided with a cuff having a continuous sealing band disposed therein of slightly larger diameter than the bottom end cap.

Abstract: For retarding oxidation of hotmix asphalt, an inert gas injection system for a storage bin equipped with a self-sealing intake door and pressure equalizing valves. Inert gas is periodically introduced into the bin by electrically timed control.

Abstract: A portable self-erecting surge storage system for temporarily storing asphaltic hotmix. The system includes a cylindrical surge bin and an elongate conveyor having a roller yoke at one end thereof to ride a track affixed on the outer surface of the surge bin. The surge bin is pivotally pinned to a subframe to enable hydraulic cylinders to pivot the bin upwardly from a horizontal transit position to an erect operational position. The roller yoke simultaneously travels up the bin track, elevating one end of the conveyor to the top of the erect surge bin. Retraction of the cylinders lowers the bin and conveyor to their transport positions for movement to another construction site.