Dear Mr. Gary Blenkhorn,

The general rules for feeding vibrating screen are as below :

1) The feed should land up on the screen in the direction of forward travel.

2) The incoming velocity should be least possible and it should be at least inclination to the screen. This is to minimise the impact force acting on the screen cloth / deck. This is to be achieved by feeding chute. While choosing the least value, one has to also see that the material will flow in all conditions without possibility of choke-up.

3) The flow should spread to the full width of the screen deck. This is to be also achieved by proper layout / design of the chute. If need be, this can be achieved by providing flaring out flats welded to bottom of chute where material is gliding. The spread angle of such a gliding chute portion is generally limited to 5 degree on each side.

Regards,

Ishwar G Mulani.

Author of Book : Engineering Science and Application Design for Belt Conveyors.

Advisor / Consultant for Bulk Material Handling System & Issues.

Email : parimul@pn2.vsnl.net.in

Tel.: 0091 (0)20 25882916 ■

Dear Mr.Gary



The Sceeen need to get the feed uniformly across the width of the equipment.

Providing chutes is a good idea provided there is enough head room available above the screen.

Other wise a vibrating distribution feeder can be given perpendicular to the screen.

The feeder is arranged with two compartments and each compartment will feed to one half of the screen. The compartments are bottom discharge type and have a triangular slots to spread the feed evenly across the width of the compartment length.

Hope this was of help

Thanks ■

IF THE INLET OF SCREEN IS IN OVAL SHAPE AND THE FEEDING CHUTE DESIGN IS IN STEP FORM WITH PROPER INCLINATION,THEN THEIR IS NO PROBLEM,THERE ARE OTHER THINGS WHICH SHOULD BE TAKEN IN TO ACCOUNT AND CAN NOT BE EXPLAINED WITHOUT SEEING THE GENERAL ARRANGEMENT DRAWINGS.WE HAVE DESIGNED LOT OF SYSTEMS WITH HAVER AND BOECKER SCREENS AND OTHER TYPE OF SCREENS IN COAL AND ORE INDUSTRIES. ■

Hi Gary: We would usually end up going to a PANT-LEG feed chute to split feed the total feed half and half to each screen deck.

The bottom edge would be parallel to angle of screen inclination and the inside design would be shelved like a rock box design to reduce wear of chutes. The bottom edge, we would normally install a sliding gate or door to push across the opening to guide material further to left or right side of screen as needed.

PANT LEGS are a pain by the way but, fairly common on big wide screens. Ideally, if you could afford the expense of a positive screw type conveyor this would be good. THE TPH is a problem normally though.

INSTALLING Inverted V risers in the feed plate will help direct flow to sides of vibrating screen box.

Keep Smiling.......George Baker MODERATOR ■