depending on the material being screened:

DECLINE SLOPE ANGLE: 33 DEGREES coarser fine screening material

DECLINE SLOPE ANGLE: 36 DEGREES finer fine screeing material

FPM: foot per minute travel....well, i do not have it at the tip of my tongue. but, for a standard 20 degree decline, it is typically 60-75 FPM travel rate.

FPM on HUMMER deck: would be quite a bit faster than 20 degree slope. the reason is of course, finer screening, needs more slope or help from mother nature to move, so...if you do a little trick you can easily calculate the FPM travel rate. lightly spray a very small pebble or stone....flourescent orange - throw it one the deck...time it going down in seconds and you can determine the travel rate easily. if i were to guess...i would say over 100 FPM easy.

also: the exciting movement is by overhead ELECTROMAGNETIC Vibrators....which run at 1800 VPM for the 33 deg units and 3600 VPM on the 36 deg decline units.

VPM: MEANS vibrations per minute vs RPM, this means the number of pulls upwards on the armature post which connects the vibratior excitor to the vibrating strip which is attached to the FINE mesh wirecloth. These meshes could be in th 50 mesh up to the 500 mesh range openings.

GEORGE BAKER

Moderator

PS: this is an old post.......but, i just read it....travelling a lot these days.

Originally Posted by dauna47

Can somebody tell me what is the slope used for an Hummer screen, and also what is the material conveying speed in feet per minute?

Thank you, best regards.

■

newer style HUMMERS: will probably use INVICTA style mechanical vibrators vs the old electro magnetic style (these old ones ran at over 107 DBA levels...real loud). The newer ones are QUIET.

Originally Posted by George Baker

depending on the material being screened:

DECLINE SLOPE ANGLE: 33 DEGREES coarser fine screening material

DECLINE SLOPE ANGLE: 36 DEGREES finer fine screeing material

FPM: foot per minute travel....well, i do not have it at the tip of my tongue. but, for a standard 20 degree decline, it is typically 60-75 FPM travel rate.

FPM on HUMMER deck: would be quite a bit faster than 20 degree slope. the reason is of course, finer screening, needs more slope or help from mother nature to move, so...if you do a little trick you can easily calculate the FPM travel rate. lightly spray a very small pebble or stone....flourescent orange - throw it one the deck...time it going down in seconds and you can determine the travel rate easily. if i were to guess...i would say over 100 FPM easy.

also: the exciting movement is by overhead ELECTROMAGNETIC Vibrators....which run at 1800 VPM for the 33 deg units and 3600 VPM on the 36 deg decline units.

VPM: MEANS vibrations per minute vs RPM, this means the number of pulls upwards on the armature post which connects the vibratior excitor to the vibrating strip which is attached to the FINE mesh wirecloth. These meshes could be in th 50 mesh up to the 500 mesh range openings.

GEORGE BAKER

Moderator

PS: this is an old post.......but, i just read it....travelling a lot these days.

■

Dear Dauna, W.S Tyler Canada is the OEM supplier of this machine if you require any parts or service please contact

Luigi Petrucci

905-688-2644 ext 1284

lpetrucci@wstyler.ca

Answer:

SLOPE

An H-Class screen will generally be operated at a slope between 31 and 36 degrees. The optimum slope for any particular job is that which will handle the greatest volume of oversize and still remove the available undersize to the required standards. The machine must be level across the width to promote proper distribution of the material being screened. To quickly and efficiently separate any material into a coarse and a fine fraction the bed thickness must be limited so that the load can be stratified. This is the action, which causes the larger pieces to come to the top of the bed, and allows the fines to work their way down to the screening surface so that they are able to pass through the openings. An increase in the slope will naturally increase the rate of travel so at a given rate of feed the thickness of the bed of material will be reduced. When you design the structure you will take into consideration the recommended angle of operation. This recommendation has been recorded in the attached “Screen Specification” in topic 1 in attachments. Even though we may not have mentioned it as a part of our recommendation keep in mind that small uncontrollable changes due to the screening characteristics of the material or even changes in your product specifications may make it desirable to change the slope. We suggest that you plan for a variation of plus or minus two degrees when you design the structure and the feed and product chutes. Keep in mind that as the slope increases the vertical distance between the elevation of the mounting points increases and the horizontal distance will decrease and vice versa.

FEEDING

Having purchased the size and type of W.S Tyler screen we have recommended for your screening application the next step will be to design an efficient arrangement for feeding the screen. The success of your installation may very well hinge on this important point. In order to fully utilize the capacity and efficiency and to minimize maintenance of the screening surface material should enter the feed area along a line parallel to the centerline of the screen. It should be fed at a uniform rate and the material should be evenly distributed across the full width of the machine. W.S Tyler provides Balance Gate Feeders that help to distribute the feed material evenly.

Any positive feeding arrangement, such as a surge bin equipped with a vibrating feeder, is an excellent investment when they are correctly selected and installed. Such feeding equipment should have controls so as to time the feeder to the capacity of the screen. Material should travel down the length of a vibrating screen at a rate of approximately 50 feet per minute. It is detrimental to introduce the feed at a higher velocity. The stratification of the bed of material, and the resulting removal of the fines, will be impaired if the material must first of all slow down to the normal velocity.

Gravity chutes are commonly used to deliver the material to the screen. The arrangement can be successful if the material is free flowing and there is no extreme surging. Chutes and spouting should be large enough and steep enough to assure a steady flow of material without danger of choking. Layout should be such that clearances required to change screen sections are not consumed. Use extreme caution if you attempt to design a split chute to feed two or more units from a single source. The vast majority of such arrangements result in the loading of only one side of each unit.

Best Regards,

Luigi Petrucci

Service Manager

W.S. TYLER

lpetrucci@wstyler.ca

Phone: (905) 688-2644 Ext. 1284 ■

Hello Luigi

Good to see you on this forum.

Gary ■