MIL-W-52125 Washing And Screening Unit, Aggregate, Electric Motor Driven, 75 Ton Per Hour CapacityThis specification covers a semitrailer-mounted, pneumatic-tired, electric-motor-driven aggregate washing and screening unit with dolly.

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MIL-W-52125B

3.11.3.1  Wire.  All screen cloth shall be made of crimping-grade, oil-tempered standard heavy wire conforming to NSGA Circular No. 80, table 3, grade B, carbon range 0.55 to 0.70, drawn and hardened.  Wire size shall be as shown in table I.

3.11.4  Vibrating mechanism.  A mechanical vibrating mechanism shall be provided for activating the live frame.  When material from the deck or decks of the screen impinges on the activating mechanism, the mechanism shall be equipped with a replaceable, protective cover. The mechanism shall be driven by a 15-hp electronic motor.

3.11.4.1  Shaft bearings.  The vibrating screen shall have double-row, self-alining, antifriction shaft bearings.  All bearings exposed to dust shall be provided with labyrinth grease and dust seals.

Table I.  Wire sizes

Clear opening (minimum)                                                Wire diameter

(Inch)

2-1/2

2

1-1/2

1

3/4

1/2

3/8

(Inch)

1/2

7/16

3/8

5/16

1/4

0.192

0.162

                              1/4                                                                                  0.135        

3.11.5  Spray pipes.  The vibrating screen shall be equipped with spray pipes above each screen deck.  Each spray pipe shall contain a multiple number of spray nozzles directed downward.  The spray pipes shall receive water under pressure from the main water header controlled by a valve and shall be provided with valves for regulating the flow or water for each deck.

3.12  Dehydrator.  The unit shall be provided with a dehydrator for fines.  The dehydrator shall have a single screw 30 inches in diameter and a tub approximately 22 feet in length, set at an angle not more than 20 degrees from the horizontal.  The screw shall be driven by a 10-hp electric motor.  A means shall be provided to flush water through the drain trough of the tub.

3.12.1  Screw.  The dehydrator screw shall be equipped with replaceable, segmental, iron or steel castings or weldments having a hardness of not less than 430 Brinell.  The upper end of the screw shaft shall be mounted on thrust-type antifriction bearings enclosed in an oiltight case

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