Brown Stock Screening

SKU: C-654Duration: 29 Minutes

Pay-per-view (PPV) format perfect for individual users.

Get immediate access to this interactive eLearning course online. Must be used within 30 days, expires 48 hours after launch.


Great for in-person classroom training or as an alternative to DVD.

Includes printable documents and Convergence Video Player for Windows systems. Content expires after 1 year.


Great for trainers or groups who need unlimited online access to multiple courses. Available in two ways:

Kraft Pulping Series (Details)
Includes 12 courses for $499/year.

Pulping Library (Details)
Includes 72 courses for $1,499/year.

Ideal for corporate licensing and high volume users.

Get Convergence courses into your current LMS to track and report employee training. Or contact us to learn more about the advantages of licensing our courses with the Convergence LMS.

 Need help deciding? Compare delivery formats.

Course Details


Training Time: 29 minutes

Compatibility: Desktop, Tablet, Phone

Based on: Industry Standards and Best Practices

Languages: English, French
 Multiple languages available for USB and Enterprise (SCORM/AICC) formats. Contact us for more info.

In the kraft chemical pulping process, wood chips are "cooked" in a mixture of alkaline chemicals in large pressure vessels called digesters. Due to irregularities in the wood, and contaminants in the incoming wood, not all of the material coming from the digester is suitable for papermaking. Brown stock screening is that part of the pulping process where oversized and contaminant particles are separated from good papermaking fibers. Pulp exiting a kraft digester is known as brown stock. Unwanted material, or debris, is generally removed in two steps, deknotting and screening.

Learning Objectives

At the end of this module, you will be able to:

  • Identify the contaminants in unscreened brown stock
  • Describe the purpose and theory of knotting and screening
  • Identify the major components of a screen/ pressure screen
  • Identify the major components of a knotter
  • Describe the screening process
  • Describe the benefits of a cascaded screening system
  • Identify factors which affect screening performance
  • Identify and describe the flows in a screen and knotter

Key Questions

The following key questions are answered in this module:

What is the purpose of brown stock screening?
The purpose of brown stock screening is to pass as many flexible usable fibers through to downstream processes while removing oversize contaminants.

What is the advantage of having a secondary knotter?
A secondary knotter processes rejects from a primary knotter and increases overall screening yield by recovering usable fiber.

What is the role of dilution water in a pressure screen?
Dilution water added to the lower part of a screen helps maintain good separation of fiber within the screen.

What is one way that pressure screens are kept from plugging?
Most cylindrical screens have a rotor which moves relative to the basket and creates pressure pulses.

What is a cascaded screening system?
A cascaded screening system is one in which the rejects of one stage of screens are re-screened in order to increase the overall screening yield.

Sample Video Transcript

Below is a transcript of the video sample provided for this module:

A rotary knotter is a coarse pressure screen. It consists of a perforated cylinder or basket held within an outer pressurized housing. Feedstock enters tangentially at the top of the vessel. This creates a swirling action which helps throw dense trapped material outward. The material which stays against the wall goes into a junk trap. This is a holding chamber outside the main screen which is periodically isolated from the screen and its contents discarded. The stock flows down along the outside of the screen basket. Small accepted fibers pass in through the basket and flow to the bottom of the screen and out of the accepts port. The particles which do not pass through the screen work their way down the outside of the basket and flow out the rejects port.

Customer Q&A

I would like to have several employees take multiple courses. How can I set that up?

We're in the process of making bulk course and multiple user purchases easier. But for now, you can order multiple courses and contact us with details on who you'd like to assign courses to. We can set up each user's training plan and make sure everyone gets the eLearning assignments they need.

Can I get a free full-length preview of a course to see what this course covers?

While we do our best to offer details on course contents, we don't normally offer full-length previews. But please contact us with more details for a better understanding of what your organizaton needs and how we can help.

Do I get a certificate when I complete a course?

Yes. All of our courses allow you to print a completion certficate upon successfully passing the integrated test at the end of each eLearning course.

How do I log in to take a course that I have already paid for?

You'll receive an email with login details moments after you purchase your pay-per-view (PPV) course. Just click the login link and enter the user name and password provided.

Do you have courses in different languages?

Yes. While all of our courses are originally produced in English, we develop many courses in a growing number of languages, including Chinese, Dutch, German, Italian, Japanese, Korean, Polish, Portuguese, Russian, Spanish, Tamil, and Thai. Available languages are normally displayed in the Course Details section on each course page.
Added to Cart! Click here to view your cart.