hr\) complete with a diesel engine driven \(DED\) power source.

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OO-M-2829

shall be provided with an adjustment lever and position locking device when

control gate is used for regulating aggregate flow.

3.14.2 Belt-conveyor feeder(s). The belt-conveyor feeder(s) shall consist

of a suitable steel frame conveyor belt, head-end (drive) pulley, foot-end

mounted under the belt to support the aggregate as it is discharged from the

aggregate hoppers. Steel dustpans shall prevent dust arid aggregate from falling

onto the backside of the conveyor belt. Steel side plates and rubber flashing

shall be provided to prevent spillage of aggregate from the sides as it is

discharged from the hopper. Pulleys and rollers shall be mounted on steel

shafts and supported by antifriction or bronze bearings with dustproof seals.

Self-aligning bearings for head and tail end pulley shafts shall be furnished

and shall be provided with labyrinth seals. The belt-conveyor feeder(s)

foot-end section shall be provided with a takeup adjustment mechanism to obtain

belt tension.

3.15 Cold-aggregate conveyor. Cold-aggregate conveyor shall be of the belt

conveyor drive type of not less than 14 inches (355 mm) in width and

manufacturer's standard length, and shall be electric motor driven.

3.16 Drum mixer. The drum mixer unit shall be semitrailer mounted and shall

include, but not be limited to, the drum mixer, aggregate feed system, burner

and blower, asphalt feed system, hot mix discharge system, dust and fines

collection system. The drum mixer shall, in addition, be capable of mixing

recycled material as specified in 3.3.

3.16.1 Drum. The drum mixer shall be a single cylinder constructed of

heavy-gage steel plate capable of withstanding the abrasion wear and heat

distortion at peak production for long usage without replacement. The drum

shall be provided with replaceable lifting flights which shall lift and drop the

aggregate in a thin veil through the hot gases produced by the burner and then

mix with hot asphalt. Suitable means shall be provided to discharge the hot mix

into the hot-mix conveyor. The drum shall be fitted with steel supporting tires

attached to the outer circumference. Each tire shall revolve on not less than

two adjustable trunnions made of hardened cast steel. Means shall be provided

for controlling the longitudinal movement of the drum along the longitudinal

axis of the drum in both the uphill and downhill direction. The drum shall be

driven by a positive or friction drive arrangement. All bearings used in the

driving mechanism shall be of the antifriction type.

3.16.2 Burner and fuel system. The burner fuel system shall include burner,

fuel piping, valves, fuel pump, strainers, sediment and moisture bowl, relief

valve, pressure gages, and other items which may be required to provide a

complete operating burner fuel system.

3.16.2.1 Burner. The mixer burner shall be low pressure, air atomizing, and

oil burning. The burner shall meet the performance requirements specified

herein, when operated with fuel oil conforming to W-F-800, grade DF-A, DF-1, or

DF-2, and jet fuel conforming to MIL-T-5624, grade JP-4 or JP-5. The burner

shall have the capacity of drying the wet aggregates to meet the specified

production requirement, and shall operate in conjunction with the forced draft

blower for efficient combustion.