FOR Proper vibrating screen sizing to determine: width x length x number of decks x EFFICIENCY factor. You need to get your hands on the VSMA handbook. In that handbook is located the VIBRATING SCREEN SIZING FORMULA which ALL vibrating screen manufacturers use typically with very slight modifications to their own formulas to either be more conservative on TPH or less conservative in TPH. More conservative = more safety factor = a bigger screen needed and less conservative = smaller screen needed....and less dollars.

SELECTION OF SCREEN SIZE AND TYPE:

applying screening area formula

a separate calaculation is required for each deck of a multiple deck screen, but the same formula is used in each deck calculation.

SCREENING AREA = U

= SQUARE FEET

A X B X C X D X E X F X G X H X J

U = UNDERSIZE: Amount in stph OF MATERIAL IN THE FEED TO THE DECK THAT IS SMALLER THAN A SPECIFIED APERTURE OR OPENING

DIVIDED BY:

FACTOR U: (UNDERSIZE) this means the amount of STPH of material in the feed to the deck that is smaller than a specified aperture.

FACTOR A: (BASIC CAPACITY): this means a predetermined rate of material in STPH through a square foot of a specified opening when the feed to the deck contains 25% oversize (factor B) and 40% halfsize (factor C)

FACTOR B: (OVERSIZE): Actual % of material in the feed to the deck that is larger than a specified aperture. (this will adjust FACTOR A) to suit the conditions

FACTOR C: (HALF-SIZE): Actual % of material in the feed to the deck that is one half the size of a specified aperture. (Also adjust Factor A)

FACTOR D: (DECK LOCATION): applies for multiple deck screeners. Total screening area is available for the top deck separation. time delay for material to pass the top deck and the 2nd deck or the 3rd deck leaves LESS effective open area available. This factor is expressed in a percent of the top deck effective area.

FACTOR E: (WET SCREENING) if a wet screen, this factor applies when water is sprayed on the material as it moves down the screening deck. Generally, about 5 to 7 GPM (gallons per minute) are used per each STPH of solids fed to the screen. the volume of water required should be supplied so that a portion is combined with the solids into a feed box to prepare a SLURRY FEED to the screen. the balance of water is added through a series of spray bars located over the screening deck.

FACTOR F: (MATERIAL WEIGHT): if the weight of the material is NOT 100 LBS per CU FT bulk density...which equals the A factor. use this formula LBS per cu foot of actual material divided by 100 . and insert this number into formula.

FACTOR G: (SCREEN SURFACE MEDIA TYPE OPEN AREA): Appiles when open area of screening surface is less than the open area shown in FACTOR A, capacity chart. FACTOR G =

% open area of screen surface being used DIVIDED BY % of open area indicated in the capacity chart

FACTOR H: (SHAPE OF THE OPENING): Applies when rectangular openings are used. Slotted or oblaong openings will in fact, PASS more material per square foot than a square opg.

FACTOR J: (EFFICIENCY): Applies when the objective or required screening EFFICIENCY is less than the standard A FACTOR, which is 95% EFFICIENCY. For example: if scalping, you do not need to be 95% efficient, more like 85% if completely acceptable. less efficiency = smaller screen needed.

SCREEN EFFICIENCY: you must double check the BED DEPTH FACTORS....MOST MOST CRITICAL after arriving at the width vs length needed from the forumula above.

HOPING THIS HELPS.. IF MORE QUESTIONS, LET er RIP. George Baker MODERATOR.

(I tried to copy my VSMA FORMULA and my scanner was not co-operating...........so, I typed all this .... painful)

Need help on how to find out screening efficiency and how it can be related to screen size selection with respect to screen efficiency factor. What are the factors that we should consider for finding out the overall screening area of a screen deck.

What are the other prominent screening model apart from Karra model.[/QUOTE] ■

ONE LAST POINT: if you buy the AGGFLOW SIZING PROGRAM from BEDROCKRESOURCES.COM it is all contained in that software to size screens and crushers. or you can just order the VSMA HANDBOOK on line....for strictly screening formulas and troubleshooting. GEORGE BAKER.

....................

FOR Proper vibrating screen sizing to determine: width x length x number of decks x EFFICIENCY factor. You need to get your hands on the VSMA handbook. In that handbook is located the VIBRATING SCREEN SIZING FORMULA which ALL vibrating screen manufacturers use typically with very slight modifications to their own formulas to either be more conservative on TPH or less conservative in TPH. More conservative = more safety factor = a bigger screen needed and less conservative = smaller screen needed....and less dollars.

SELECTION OF SCREEN SIZE AND TYPE:

applying screening area formula

a separate calaculation is required for each deck of a multiple deck screen, but the same formula is used in each deck calculation.

SCREENING AREA = U

= SQUARE FEET

A X B X C X D X E X F X G X H X J

U = UNDERSIZE: Amount in stph OF MATERIAL IN THE FEED TO THE DECK THAT IS SMALLER THAN A SPECIFIED APERTURE OR OPENING

DIVIDED BY:

FACTOR U: (UNDERSIZE) this means the amount of STPH of material in the feed to the deck that is smaller than a specified aperture.

FACTOR A: (BASIC CAPACITY): this means a predetermined rate of material in STPH through a square foot of a specified opening when the feed to the deck contains 25% oversize (factor B) and 40% halfsize (factor C)

FACTOR B: (OVERSIZE): Actual % of material in the feed to the deck that is larger than a specified aperture. (this will adjust FACTOR A) to suit the conditions

FACTOR C: (HALF-SIZE): Actual % of material in the feed to the deck that is one half the size of a specified aperture. (Also adjust Factor A)

FACTOR D: (DECK LOCATION): applies for multiple deck screeners. Total screening area is available for the top deck separation. time delay for material to pass the top deck and the 2nd deck or the 3rd deck leaves LESS effective open area available. This factor is expressed in a percent of the top deck effective area.

FACTOR E: (WET SCREENING) if a wet screen, this factor applies when water is sprayed on the material as it moves down the screening deck. Generally, about 5 to 7 GPM (gallons per minute) are used per each STPH of solids fed to the screen. the volume of water required should be supplied so that a portion is combined with the solids into a feed box to prepare a SLURRY FEED to the screen. the balance of water is added through a series of spray bars located over the screening deck.

FACTOR F: (MATERIAL WEIGHT): if the weight of the material is NOT 100 LBS per CU FT bulk density...which equals the A factor. use this formula LBS per cu foot of actual material divided by 100 . and insert this number into formula.

FACTOR G: (SCREEN SURFACE MEDIA TYPE OPEN AREA): Appiles when open area of screening surface is less than the open area shown in FACTOR A, capacity chart. FACTOR G =

% open area of screen surface being used DIVIDED BY % of open area indicated in the capacity chart

FACTOR H: (SHAPE OF THE OPENING): Applies when rectangular openings are used. Slotted or oblaong openings will in fact, PASS more material per square foot than a square opg.

FACTOR J: (EFFICIENCY): Applies when the objective or required screening EFFICIENCY is less than the standard A FACTOR, which is 95% EFFICIENCY. For example: if scalping, you do not need to be 95% efficient, more like 85% if completely acceptable. less efficiency = smaller screen needed.

SCREEN EFFICIENCY: you must double check the BED DEPTH FACTORS....MOST MOST CRITICAL after arriving at the width vs length needed from the forumula above.

HOPING THIS HELPS.. IF MORE QUESTIONS, LET er RIP. George Baker MODERATOR.

(I tried to copy my VSMA FORMULA and my scanner was not co-operating...........so, I typed all this .... painful)

Need help on how to find out screening efficiency and how it can be related to screen size selection with respect to screen efficiency factor. What are the factors that we should consider for finding out the overall screening area of a screen deck.

What are the other prominent screening model apart from Karra model.[/QUOTE][/QUOTE] ■

FINALLY got my scanner working: here are the pages from VSMA.

Originally Posted by George Baker

ONE LAST POINT: if you buy the AGGFLOW SIZING PROGRAM from BEDROCKRESOURCES.COM it is all contained in that software to size screens and crushers. or you can just order the VSMA HANDBOOK on line....for strictly screening formulas and troubleshooting. GEORGE BAKER.

....................

FOR Proper vibrating screen sizing to determine: width x length x number of decks x EFFICIENCY factor. You need to get your hands on the VSMA handbook. In that handbook is located the VIBRATING SCREEN SIZING FORMULA which ALL vibrating screen manufacturers use typically with very slight modifications to their own formulas to either be more conservative on TPH or less conservative in TPH. More conservative = more safety factor = a bigger screen needed and less conservative = smaller screen needed....and less dollars.

SELECTION OF SCREEN SIZE AND TYPE:

applying screening area formula

a separate calaculation is required for each deck of a multiple deck screen, but the same formula is used in each deck calculation.

SCREENING AREA = U

= SQUARE FEET

A X B X C X D X E X F X G X H X J

U = UNDERSIZE: Amount in stph OF MATERIAL IN THE FEED TO THE DECK THAT IS SMALLER THAN A SPECIFIED APERTURE OR OPENING

DIVIDED BY:

FACTOR U: (UNDERSIZE) this means the amount of STPH of material in the feed to the deck that is smaller than a specified aperture.

FACTOR A: (BASIC CAPACITY): this means a predetermined rate of material in STPH through a square foot of a specified opening when the feed to the deck contains 25% oversize (factor B) and 40% halfsize (factor C)

FACTOR B: (OVERSIZE): Actual % of material in the feed to the deck that is larger than a specified aperture. (this will adjust FACTOR A) to suit the conditions

FACTOR C: (HALF-SIZE): Actual % of material in the feed to the deck that is one half the size of a specified aperture. (Also adjust Factor A)

FACTOR D: (DECK LOCATION): applies for multiple deck screeners. Total screening area is available for the top deck separation. time delay for material to pass the top deck and the 2nd deck or the 3rd deck leaves LESS effective open area available. This factor is expressed in a percent of the top deck effective area.

FACTOR E: (WET SCREENING) if a wet screen, this factor applies when water is sprayed on the material as it moves down the screening deck. Generally, about 5 to 7 GPM (gallons per minute) are used per each STPH of solids fed to the screen. the volume of water required should be supplied so that a portion is combined with the solids into a feed box to prepare a SLURRY FEED to the screen. the balance of water is added through a series of spray bars located over the screening deck.

FACTOR F: (MATERIAL WEIGHT): if the weight of the material is NOT 100 LBS per CU FT bulk density...which equals the A factor. use this formula LBS per cu foot of actual material divided by 100 . and insert this number into formula.

FACTOR G: (SCREEN SURFACE MEDIA TYPE OPEN AREA): Appiles when open area of screening surface is less than the open area shown in FACTOR A, capacity chart. FACTOR G =

% open area of screen surface being used DIVIDED BY % of open area indicated in the capacity chart

FACTOR H: (SHAPE OF THE OPENING): Applies when rectangular openings are used. Slotted or oblaong openings will in fact, PASS more material per square foot than a square opg.

FACTOR J: (EFFICIENCY): Applies when the objective or required screening EFFICIENCY is less than the standard A FACTOR, which is 95% EFFICIENCY. For example: if scalping, you do not need to be 95% efficient, more like 85% if completely acceptable. less efficiency = smaller screen needed.

SCREEN EFFICIENCY: you must double check the BED DEPTH FACTORS....MOST MOST CRITICAL after arriving at the width vs length needed from the forumula above.

HOPING THIS HELPS.. IF MORE QUESTIONS, LET er RIP. George Baker MODERATOR.

(I tried to copy my VSMA FORMULA and my scanner was not co-operating...........so, I typed all this .... painful)

Need help on how to find out screening efficiency and how it can be related to screen size selection with respect to screen efficiency factor. What are the factors that we should consider for finding out the overall screening area of a screen deck.

What are the other prominent screening model apart from Karra model.

[/QUOTE][/QUOTE]

Attachments

vsma selection of screen size & type (JPG)

vsma screen size & type (JPG)

vsma screen sizing formula 2 (JPG)

vsma screen sizing formula (JPG)

■

Originally Posted by tanmaytega

Need help on how to find out screening efficiency and how it can be related to screen size selection with respect to screen efficiency factor. What are the factors that we should consider for finding out the overall screening area of a screen deck.

What are the other prominent screening model apart from Karra model.

If you want to send through your application details then we can tell you what efficiency you should be able to achieve on the size of machine you have.

If you can send:-

- TPH

- Material (Sand/Coal etc)

- Bulk Density (t/m3)

- Cut Size each deck (mm)

- Type of Deck (Wire/P.U etc)

- Inclined/Horizontal

-Wet/Dry

-Feed Grading (% passing)

Many thanks. ■