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SCREENING

DiamondRoll® Thickness Screens

Selective screening & chip removal

  • With Cover
  • No Cover
acrowood-diamondroll-thickness-screen-feature
acrowood-diamondroll-thickness-screen-no-covers-feature

Acrowood DiamondRoll® Thickness Screen

Chip Thickness Screening is based on the ability of a screen to selectively remove only those chips that are too thick for the pulping process. Many screens have been used in an attempt to achieve this separation and none has succeeded like the DiamondRoll® Thickness Screen.

DiamondRoll® Thickness Screen Features

  • Most accurate chip thickness screen on the market
  • Highly accurate selectivity retained in every installation over years of reliable operation
  • Changing thickness targets easily achieved with simple, on-site shim changes
  • Roll surfaces are hard chromed for long wear life
  • Highest overthick removal efficiency of any screen type
  • Maximizing your natural resources
  • Scale-able based on the need and type of application (Large or small units available)
  • Obtain a higher yield of pulp from raw materials coming in, resulting in immediate savings
  • Video Demo 1
  • Video Demo 2
diamondroll-thickness-screen-03
Acrowood engineering, manufacturing, sales and service staff work in tandem to provide the best equipment and installation for your mill.
The Acrowood Approach
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How It Works

The principle of operation of this unique screen lies in the use of solid shafts, or rolls. These rolls move and agitate a mat of chips as they are fed from the infeed of the screen, letting the smallest chips pass between the shafts first.

Gradually the larger chips are concentrated on the surface of the rolls, until they are finally discharged off the end. In the nip between the rolls is a gap of free space that lets the acceptable chips fall through. The distance in this gap is what makes all the difference!

DiamondRoll Shafts with bumpers
DiamondRoll-Nihon-Itagami-Screw-and-DiamondRoll-Thickness-Screen

Getting The “Good” Chips

For most pulping processes a maximum allowable chip thickness is between 8 and 10 mm. This means that chips larger than 8 mm must be sorted out of the mass of chips that make the feedstock for the pulping process, and treated separately to make them acceptable.

Chips between 2 mm and 8 mm are generally considered to be “good” chips, or Accepts, but larger chips result in high levels of knotter rejects in the pulp mill, and reduce pulping efficiency. Accurately separating these large chips is critically important to the economic success of the pulping process.

DiamondRoll-DiamondRoll-Thickness-Screen-Drive-Detail
We are a 100% sawmill residual mill, so chip quality is important to us. We rely on the DiamondRoll Thickness Screen to prevent overthick chips from getting into the digester. It has done a great job. “
Pulp Mill Superintendent
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Superior Engineering

VIRO Makes the Difference! What makes this screen so special? Variable InterRoll Opening (VIRO) technology! The ability to set the distance between the shafts to virtually any opening needed is a feature unique to the DiamondRoll Thickness screen. The drive system, slotted side frame, bearing block supports, and machined DiamondRoll shafts all fit together in one seamless system of strength, selectivity, and performance. No other screen matches it in terms of efficiency or performance!

Shaft spacing is adjusted by changing shims between bearing blocks in the side frame of the screen. The bearing blocks for each shaft run in a slot cut into the frame, separated by these “shim” spacers.

Using spacers between the blocks sets the spacing between the rolls. If a larger opening is needed, additional shims can be added. If the rolls need to come closer together, a thinner shim is used. In either case it is a simple and quick matter to alter the screen, and can be done in a few short hours, without the need of special tools.

DiamondRoll-diamondroll-thickness-screen-shafts-close-up
DiamondRoll blue-covered-unit

Machine Basics

Each DiamondRoll roll starts out as a solid alloy steel shaft. It is machined to a precisely specified diameter, cut with the diamond pattern, has the chambered shaft end added at the end, and is finished with a journal on each end to mate with the specially designed housing and bearing. The entire surface is hard chromed for long service life.

The drive is a loop chain design using lube-free chain and special sprockets. This highly efficient design makes it possible to keep the drive simple and maintenance free, yet drive the longer and higher capacity screens needed by mills today.

The side frames are steel plate with aluminum drive enclosures. Dust covers are provided. Screens are shipped either fully assembled, or they can easily be assembled in place to save on installation costs.

Integrated Scalping Screen

It is possible to include a scalping screen section after the thickness screening section. The shafts used here are typically cut with a deeper knurl pattern, and set 20 to 30 mm apart. This section rejects large strings, knots, and cards present in the chip flow, protecting the overthick chip processing equipment that follows.

Specifications: DiamondRoll Thickness Screen (imperial)
Roll Width60728496108120132144156
width (in)
# of RollsMotor (HP)Weight (tons)Motor (HP)Weight (tons)Motor (HP)Weight (tons)Motor (HP)Weight (tons)Motor (HP)Weight (tons)Motor (HP)Weight (tons)Motor (HP)Weight (tons)Motor (HP)Weight (tons)Motor (HP)Weight (tons)
40109.51010.51511.51512.5----------
5015111512.31513.51514.81516--------
6015131514.31515.51516.81518.31519.52021.32022.32023.8
70--1516.31517.81519.32020.82022.32023.82025.32026.8
80----1519.82021.42023.02024.82026.32028.02029.8
90------2023.82025.62027.52029.32031.12533.1
100------2026.02028.02030.02032.02534.02536.0
110----------2532.92535.12537.32539.9
Specifications: DiamondRoll Thickness Screen (metric)
Roll Width1.51.82.12.42.73.03.43.74.0
width (m)
# of RollsMotor (KW)Weight (mt)Motor (KW)Weight (mt)Motor (KW)Weight (mt)Motor (KW)Weight (mt)Motor (KW)Weight (mt)Motor (KW)Weight (mt)Motor (KW)Weight (mt)Motor (KW)Weight (mt)Motor (KW)Weight (mt)
407.59.77.510.71111.71112.7----------
501111.21112.41113.71115.01116.3--------
601113.21114.51115.71117.01118.51119.81521.61522.61524.1
70--1116.51118.01119.61521.11522.61524.11525.71527.2
80----1120.11521.71523.41525.11526.71528.41530.2
90------1524.11526.01527.91529.71531.618.533.7
100------1526.41528.41530.51532.518.534.518.536.6
110----------18.533.418.535.718.537.818.540.5

DiamondRoll Thickness Screen Diagram of Machine Length & Width and Screening Width

DiamondRoll Thickness Screen diagram drawing of machine width and length and available screening area for wood chips.
DiamondRoll Thickness Screen diagram describing the machine width, length and available screening width for pulp mill wood chip screening.

DiamondRoll Thickness Screen Dimensions Diagram with optional Dust Covers

DiamondRoll Thickness Screen diagram example of specs with the optional dust covers on
DiamondRoll Thickness Screen diagram example of specs with the optional dust covers on.

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The DiamondRoll® Thickness Screens brochure

Request the DiamondRoll thickness screen machine brochure provided to you in PDF format for easy reading and printing.

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Case Study: Primary Thickness Screening, Efficiency and Chip Size Distribution

The big advantage of the DiamondRoll screen is that the solid steel rolls are set in the frame of the screen in such a way that the opening dimension is highly uniform. Since the shafts don’t vibrate and are not subject to bending or damage, the IRO is consistent over the operational life of the screen.

VIEW CASE STUDY

Case Study: Pulping System Sensitivity to Chip Quality

What this means is that the rate limiting dimension of the chip is its smallest dimension, which is its thickness. This was the critical discovery that resulted in Chip Thickness Screening (CTS), and the resultant rush to install CTS systems in every Kraft mill in the world.

VIEW CASE STUDY

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Shipping Address

Acrowood Corporation
4425 S. Third Ave.
Everett, WA 98203
USA

Mailing Address

Acrowood Corporation
PO Box 1028
Everett, WA 98206-1028
USA
Tel: 1 (425) 258-3555
Fax: 1 (425) 252-7622

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  • Home
  • About
    • Executive Team
  • Products
    • Debarking Machines
      • Batch Debarker
      • Continuous Rotary Debarker
    • Chipping
      • Whole Log Chipper
      • Slant Disc Chipper
      • Veneer Chipper and Feedworks
      • Rechipper
      • Chip Cracker
      • Chip Slicer
    • Screening
      • Trillium® OSB Strand Screen
      • Disc Thickness Screen
      • HD Disc Scalping Screen
      • Dual Drive Suspended Rotary Screen
      • DiamondRoll® Fines Screens
      • DiamondRoll® Thickness Screens
      • DiamondRoll® Particle Screen
    • Distribution & Separation
      • Air Density Separator
      • Star Feeder
      • Screw Distributor
  • Development Center
  • Case Studies
  • Expertise
    • Pulp Mills
    • Saw Mills
    • Panel Board Mills
    • Biomass & Pellet Mills
    • DiamondRoll Shaft Wear [Assessment Guide]
    • Blacksmithing custom bolts the old fashioned way [Technical Article]
  • Contact
  • Jobs
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