Gentle Roll™ Technical Data
- Drum Design
- Screen Blinding (plugging)
- Solutions to Blinding
- Screen Replacement
- Screen Selection
- Hopper Model Discharge
- Conveyor Model Discharge
- Options and Accessories
For every foot of forward movement, product rolls over 6.28 sq ft, which is 25.12 sq ft for every screen section.
Screen efficiency is the percentage of product of a size that will pass through a screen that is in the product before screening. An example would be a product to be cleaned has 10 lbs of product that will pass through the screen opening selected. The cleaner removed 9 lbs of product during cleaning. The cleaner had a 90 percent efficiency.
Screen efficiency is maximized in a Gentle Roll™ by the controlled forward movement and gentle rollover action of the product. In the Model 24, the product gently rolls over 6.28 feet of screen for every foot of forward movement (25.12 feet for standard four foot screen section). This insures that all of the product will be in contact with the screen at some point during the drum rotation. This results in a high percentage of the product smaller than the screen opening passing through the screen openings. In a shaking or vibrating type screener the product must not be over feed or the top layer of product will not come in contact with the screen, which results in very low screening efficiency.
Screen Blinding (Plugging)
When products have a tendency to lodge in screen openings, this is commonly referred to as "blinding". When screen blinding occurs the Gentle Roll™ solution is a free rolling rotary brush that will roll against the screen as the drum rotates. The brush gently pushes the particles that are stuck in the screen back into the drum, minimizing blinding. This solution has been successful with many different products. The Gentle Roll™ has maintained screen efficiency with many products without using brushes. The Gentle Roll™ process helps in keeping screens open by the larger product gently rubbing against the lodged products.
Comparing Solutions to Blinding
Shaking or vibrating cleaners use balls to try to prevent screen blinding. The balls impact the bottom of the screen which can force slightly bigger particles into the screen opening & cause screen blinding. The "hammer action created by the balls can be effective in forcing near size lodged product out of the screen opening. However the constant impacting will result in damage to some fragile product and will cause screen damage over time. There are other methods used by different types of screeners to prevent screen blinding; however, no method has been able to achieve total success.
- 1500 bushels per hour of good flowing grain (corn, etc.)
- 1900 cubic feet per hour good flowing product (small pellets)
- 1200 cubic feet per hour poor flowing product (cubes)
- 43 tons per hour of standard grains (corn, etc.)
The stated capacity of 1900 CFH or 1500 BPH (free flowing product) is the true throughput capacity of one gentle roll drum. Standard units cannot be over fed. Example: If you need 15,200 CFH or 12,000 BPH we will provide an eight drum machine. The number of screens on each drum will be based on your cleaning quality requirements. The number of screens on a drum does not affect throughput capacity. One screen through five screen drums will all have the same throughput capacity. Gentle Roll™ throughput capacity is normally its cleaning capacity but is not always cleaning capacity, only testing of your product can determine cleaning capacity as well as throughput capacity. A scalping concentrator may be installed on the drums to reduce good product from remaining in the overs during scalping.
Testing of the product is a major step in the screener selection process to make sure the results obtained will be acceptable. Gentle Roll™ testing should be performed if the product to be cleaned has not been successful with the Gentle Roll™ in the past or when there is any doubt that the end result will meet the needed results established. A small initial sample of about one cu. ft. normally is analyzed to confirm that Gentle Roll™ has the potential to obtain the desired results. When the initial results are positive, then a larger sample of about 60 cu. ft. should be tested. If the Gentle Roll™ is determined to not be the proper cleaning system, then the type of cleaner that may meet the requirements will be recommended when possible.
- Standard is mild steel painted or hot dipped galvanized (stainless optional)
- Dust tight
- Weather resistant
Installation of Gentle Roll™
- All Gentle Roll™ units should be installed close to a level horizontal position.
- Foot mounting, suspension, or a combination is acceptable.
- Rigid or loose mounting is acceptable as no vibration, horizontal, or vertical movement results from Gentle Roll™ operation
- A 24 inch clearance is recommended on ends and sides. Consult engineering for minimums.
- Spouting to and from all flange connections can be ridged. Mating flanges come with all units.
- Conveyor and hopper bottom units are shipped assembled as much as possible. Gentle Roll™ can be disassembled to pass through standard door opening. (Hoppers must be ordered in sections if this is required.)
- Multiple drum units are of stackable design. Hoppers are mounted to lower section. The cover mounts to top section.
- Inlets on stack units are of manifold type.
Each gentle roll drum is powered separately with a drive assembly with a minimum of class II service factor. The speed reducer is a standard off the shelf shaft mounted reducer, not a special item, keeping possible down time to a minimum. Standard T frame motors are standard. V-belts & pulleys are used, allowing speed changes if needed. An adjustable frequency controller is used when cleaning products that require minor speed changes.
- Two heavy duty spherical type bearings are used on drums (externally mounted).
- Two flange bearings are used on each rotary screen brush.
- The time it takes to change screens is approximately 8 - 10 minutes.
- Access: A light weight door with quick release latches allows access to each screen on multiple drum machines. A light weight hood is used on a single drum machine with two clamp bands.
- Retention: Five 5/16 inch bolts hold the screen to the drum. Hand or power tools can be used.
- Procedure for multiple drum machines - Change screen one side at a time with the power locked out on all drums on the side screens are being changed on. (Running one side while changing screens on the other side is safe due to internal design. Each drum is independently driven, providing the operator flexibility with there production schedule. A Gentle Roll™ exclusive.) Single drum units are very similar except full production status will stop, and screen changing is done from the top.
Wire size, clear opening, & material used are selected to meet the requirements of the customer's product. Standard model 24 will have 48 inch wide screens rolled to fit 24 inch diameter drums.
Gentle Roll™ is backed by a one year warranty and the unmatched service of EBM Manufacturing, so it can be purchased with confidence.
Hopper Model Discharge
- Each screen can discharge into a separate hopper or can be mounted so more than one screen discharges into one hopper.
- Overs discharge into a separate hopper at the end of the drum.
- Offset or center discharge is available.
Conveyor Model Discharge
Two way valve assemblies consisting of a full length valve under each screen and overs valve is mounted to the Gentle Roll™ frame. This valve directs product to the right or left side of the opening and is connected directly to an EBM Patented Sidewinder conveyor or to two conveyors of a different type. Internal valve design is available on single level one and two drum models only.
Options and Accessories Available
- Urethane liner for drum flighting
- Scalping concentrator
- Hoppers lined or unlined
- Hot dipped galvanizing external parts instead of painting
- Stainless steel construction instead of mild steel
- Special feeder inlets for hard to flow product
- Explosion proof motors
- Valves: a valve assembly incorporated in to the Gentle Roll™ frame has a full width two way valve under each screen to attach EBM Sidewinder drag conveyor or other types of conveyor
- Can be shipped as and assembled or disassembled unit
- Gates manual or powered
- Service platforms
- Screen brushes
- Vent ports for aspiration
Very little maintenance is required. Recommended maintenance points:
- Gentle Roll
- Grease main bearings on each end of drum
- Proper adjustment of drum seal
- Inspection of screens
- Check fluid level on gearbox
- Belt tracking
- Inspection of flights and belt
- Inspect air take-up
- Check fluid level on gearbox
* Intervals will vary based on use
Contact us to discuss all your applications or questions toll free at (877) 370-4948 or email sales(at)ebmmanufacturing.com