Building a Grizzly Bar Screener: Design, Construction, and Applications

[MikePhua]

A grizzly bar screener is a vital piece of equipment in many industries, used to separate large rocks and debris from smaller materials. Typically found in mining, aggregate processing, and construction, these devices use a series of bars or grids to allow fine materials to pass through while trapping larger pieces. Building a custom grizzly bar screener can be a valuable project for businesses or individuals involved in material handling, offering a cost-effective solution and the ability to tailor the equipment to specific needs.
What is a Grizzly Bar Screener?
A grizzly bar screener is a simple yet effective tool designed for sorting materials by size. It consists of parallel bars arranged in a grid-like structure, with spaces between them that allow smaller particles to fall through while larger materials are retained. These screens are often used for sorting rocks, gravel, sand, and other materials in mining, construction, and even in recycling operations.
The primary function of a grizzly screener is to filter out oversize material before it moves onto other processing equipment. By using a grizzly bar screen, operators can reduce wear and tear on crushers, grinders, and other machinery by preventing oversized pieces from clogging the system.
Types of Grizzly Screens
There are several types of grizzly screens depending on their intended use:

1. Static Grizzly:
   • The static grizzly is the most basic form of screening, composed of fixed bars or grids that allow material to pass through by gravity.
     
   • It is often used for coarse material sorting, where the flow of material is not constant.
     
2. Vibrating Grizzly:
   • A vibrating grizzly uses mechanical vibrations to help separate material.
     
   • This type is more effective for wet, sticky, or fine materials that need additional movement to help pass through the bars.
     
3. Heavy-Duty Grizzly:
   • This version is made from stronger materials to handle heavy loads and more abrasive materials.
     
   • Often used in mining or demolition where large, hard materials need to be sorted.
     
4. Hydraulic Grizzly:
   • Incorporates hydraulic controls to adjust the spacing between the bars, allowing for quick customization depending on the material being processed.
     

Steps to Build a Custom Grizzly Bar Screener
Building a custom grizzly bar screener involves several stages, from initial design to final assembly. Here is a step-by-step guide to creating one.
1. Designing the Grizzly Bar Screener
The design of your grizzly screen will depend on several factors, including:

• Material to be processed: Whether you're screening rock, dirt, gravel, or other materials, the size and hardness of the material will influence the spacing between bars.
  
• Bar spacing: The gaps between the bars should be adjusted according to the size of the material you want to screen. Typically, the spacing should be between 2 to 6 inches, but it can vary.
  
• Length and width of the screen: Consider how much material you need to process at once. The larger the surface area, the more material can be sorted.
  
• Incline angle: The angle of the screen impacts the flow of materials. A typical incline angle ranges from 15 to 30 degrees, depending on the material being processed.
  

2. Selecting Materials
The materials used for constructing the grizzly bar screener must be durable enough to withstand the harsh environments in which they will operate. The key components to focus on are:

• Bars: The bars must be made from high-quality steel or alloy to resist wear and impact. Harder alloys, such as manganese steel, are often chosen for their durability in harsh conditions.
  
• Frame: The frame should be made of thick steel to support the bars and withstand heavy loads. Structural steel is a popular choice.
  
• Springs or Vibrating Mechanism: If building a vibrating grizzly, high-quality springs or a mechanical vibration system will be needed to facilitate material movement.
  

3. Building the Frame
The frame serves as the backbone of the grizzly screener. It must be strong enough to support the bars and the weight of the material being processed. The frame should be welded together from steel beams and tubes, with enough rigidity to avoid warping under pressure.
Make sure to include provisions for mounting the screen at an appropriate incline. The frame should also allow for easy attachment to machinery like excavators, front loaders, or trucks, depending on how the screener will be used.
4. Attaching the Grizzly Bars
The grizzly bars are typically welded into place, though in some designs, they may be bolted for easier replacement. The spacing between bars must be precise to ensure that the desired material is separated. Bars can be either straight or tapered, depending on the type of material you need to separate.
For larger materials, you may want to space the bars further apart. For finer materials, tighter spacing will be necessary. Customizing the size of the gaps between bars is one of the advantages of building your own screener.
5. Adding the Vibrating Mechanism (Optional)
If you choose to add vibration to your grizzly screen, this will help material move more freely through the bars. A vibrating grizzly uses a mechanical or hydraulic system to create vibrations that encourage material to fall through the gaps. This is especially useful when working with wet or sticky materials like clay or soil.
The vibration system is typically mounted underneath the bars and connected to a motor or hydraulic system. Proper tension and balancing of the vibrating mechanism are essential to ensure efficient operation.
6. Testing and Adjusting the Screener
Once your grizzly screener is assembled, it's important to test it with various types of material. Adjust the spacing between the bars if necessary, and check the flow of material to ensure it is being sorted correctly. The frame should also be inspected for any weak points or areas where it may be prone to wear.
Testing helps identify any necessary adjustments to the angle of the screen, bar spacing, or vibration system.
Maintenance and Troubleshooting
Regular maintenance is essential to keep your grizzly screener working at peak efficiency. Some key maintenance tasks include:

• Checking bar wear: Over time, the bars will become worn from contact with rocks and other hard materials. Inspect them regularly for signs of damage or excessive wear.
  
• Cleaning: Material buildup can reduce the efficiency of the screen. Periodically cleaning the bars and frame will ensure that the machine continues to operate effectively.
  
• Vibration system: If your grizzly has a vibrating mechanism, check the springs or motor for wear and tear. Ensure that they are functioning properly to avoid interruptions in the sorting process.
  

Benefits of a Custom Grizzly Bar Screener
Building a grizzly bar screener has several advantages:

1. Customization: A custom-built screener can be tailored to specific material types and processing needs.
   
2. Cost Efficiency: Instead of purchasing a pre-made screener, building your own can be a more cost-effective option, especially if you have access to spare parts and tools.
   
3. Durability: A well-built grizzly screener can last for years with proper maintenance, providing a long-term solution for material sorting.
   

Conclusion
A grizzly bar screener is an essential tool for many industries that deal with material handling. Building one yourself can be a rewarding project, offering customization, cost savings, and the satisfaction of creating something that fits your exact needs. Whether you need a static screen for simple material sorting or a vibrating grizzly for more demanding tasks, understanding the design and construction process can help ensure that your grizzly screener operates efficiently for years to come.