Laboratory Scale Hammer Mills: Top 5 FAQs [slideshare]

Posted by Cassie Brown

Jun 2, 2015 12:11:16 PM


 

  

 



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Schutte-Buffalo Hammermill Announces New Ownership

Posted by Cassie Brown

Jan 7, 2015 12:31:42 PM

We are pleased to announce the recent acquisition of Schutte-Buffalo Hammermill, LLC. Please join us in welcoming our new CEO, Martin Berardi. The follwing press release cites the details of this exciting new chapter for our company.

 

January 5, 2015  Buffalo, NY - Effective December 29, 2014, Ownership of industrial manufacturing company, Schutte-Buffalo Hammermill, LLC has been acquired by Martin Berardi.

Incoming Chief Executive Officer, Martin Berardi is a recent retiree of Moog, Inc. where in the course of 34 years he served in a variety of roles ranging from sales, operations and general management to senior corporate leadership. Berardi's long-term experience in a successful manufacturing company, both domestic and international, positions Schutte-Buffalo Hammermill for continued growth potential and additional avenues to explore. Mr. Berardi has also been an active member of the Buffalo and Western New York community in various leadership positions including education, business groups and non-profit organizations.

Ownership of Schutte-Buffalo Hammermill has transferred from Thomas Warne and James Guarino who purchased the compnay in 2004 following a merger with Buffalo Hammermill Corporation. During their tenure Warne and Guarino brought about significant growth by maintianing a leadership role in key industries such as wood waste reduction, and feed and grain processing, while broadening their reach to emerging markets such as biomass processing and alternative fuels, as well as e-scrap, asphalt, and carpet recycling.

"Both Jim and I are excited to be a part of this new phase of Schutte-buffalo Hammermill. We look forward to being on Marty's team as we continue to provide the highest quality equipment for our customers," says Tom Warne, President.

"I have great confidence in the present Schutte-Buffalo Hammermill leadership, and I am pleased that Tom and Jim will be staying on in their current roles of President and General Manager, respectively," says Martin Berardi, CEO. "Our focused efforts will be to expand the business aggressively, and to provide opportunity for further employment growth in Western New York."

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How Does a Hammer Mill Work? [Slideshare]

Posted by Cassie Brown

Oct 1, 2014 3:10:51 PM

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How is Finished Particle Size Determined?

Posted by Cassie Brown

Aug 8, 2013 11:22:00 AM

 

In any given size reduction application, the specific properties of the material being processed play a key role in how finished particle size reduction is achieved. Hardness, brittleness, moisture content, oil content, etc. are all considered when determining not only the appropriate style of size reduction equipment, but also the configuration of the equipment's internal components.

70% Control

In the majority of hammer mill applications, the key factor determining finished particle size is the the screen. Any material that enters the grinding chamber must be reduced to a size small enough to pass through the screen that covers the mill's discharge opening. Because of this the screen size provides 70% of the control over the finished particle size.

Size reduction takes place when material is fed into a hammer mill's grinding chamber and it is repeatedly struck by flailing ganged hammers that are attached to a rotor spinning at very high speed. A combination of hammer blows, collision with the walls of the grinding chamber, and particle on particle impact reduce the material until it is able to pass through the screen.

hammer mill diagram

 

Sizing up Screens

Screens and bar grates are constructed from steel and are available with perforations (screens) or spaces (bar grates) in a broad range of sizes.  Screen size is determined by the size of the openings in the screen, and is described in the following units of measure: inches, millimeters, microns (one millionth of a meter), and US mesh (the number of wires running east/west and north/south in one square inch of screen).

hammer mill screens

The appropriate screen size is determined by the desired finished particle size, and the properties of the material being processed. That is, characteristics such as friability and moisture content have an effect of the manner in which a material will break down. As a result, using the same screen to process materials of different properties will result in a range of different finished particle sizes.

For example:

particle size distribution example

This variation is called particle size distribution, and it is based on the the individual properties of the materials being processed. 

In this example: Glass is very friable, and will shatter very easily upon impact. In comparison, green wood chips are a fibrous material with a moisture content of up to 50%, which both effect the ease with which they are reduced. Finally, computer hard drives are very hard and comprised mostly of metals, making them comparatively hard to process and unlikely to breakdown beyond the screen or bar grate size.

The Force Factor

But screen size only accounts for 70% of what determines the finished particle size. The reamining 30% is attributed to the force of the impact on the material being processing. In the case of hammer mills, force is determined by rotor speed, and the size and number of hammers.

Let's take a closer look, this time using the example of a drinking glass:

Rotor Speed: Slowly tap the glass with a hammer and it will break into perhaps 3 to 4 large pieces. Conversely, if you hit it with the same hammer at a rapid speed, it will break into many more, much smaller pieces.

Hammer Size: Strike a water glass with a butter knife, and it will break into a few large pieces. Strike the same glass with a sledge hammer, and it will shatter into 1000+ pieces.

In short:

 factors determining finished particle size

Summary

Finished particle size is determined by a combination of screen size, rotor speed, and the size and number of hammers. Material must remain in the grinding chamber until it is able to pass through the screen covering the hammer mill's discharge opening. Optimal screen size is determined by the desired finished particle size, and the properties of the material being processed.

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Topics: particle size, green wood chips, hammer configuration, rotor speed, bar grates, material size reduction, moisture content, particle on particle contact, hard drives, particle size distribution, screens, hammer size

Hammer Mill Improves Craft Brewery’s Efficiency [Case Study]

Posted by Cassie Brown

Jul 31, 2013 10:07:00 AM

 

Tin Man Brewing Companytin man brewing company logo

1430 West Franklin Street

Evansville, IN 47710

www.tinmanbrewing.com

 

 

Processing:  Wheat, rye, malted barley, unmalted barley

End product:  Beer

 

Forward Thinking Brewers

The Tin Man Brewing Company of Evansville, Indiana is an early adopter in the craft brewery world.  They are one of the first craft breweries to utilize a mash filter in their brewing process. It’s a relatively simple, yet highly effective concept.  Tin Man’s Head Brewer Sean O’Rear describes the mash filter as a plate and frame filter that is loaded with brewer’s mash, a mixture of water and grains. The filter is then compressed to extract the liquid “wort”. The collected wort is then boiled with hops to produce beer.  Bonus:  the remaining solid portion, called spent grain, is given to a local farmer for use as cow feed!

The key benefit of mash filtering is that it allows for capturing up to 98% of the available sugar in the brewing grains, compared to 75% captured by more traditional methods. 

 tin man brewing company mash filter

Size Reduction Challenge

In order to achieve the goal of capturing 98% of the sugar, the grains had to be processed to a very small particle size prior to filtering. Initially, Tin Man was utilizing a two-roller stripper mill to reduce the grains. Unfortunately, the results were inconsistent at best, producing flour, uncracked kernels, and everything in between.  This  caused backups in filtering to occur, leading to significant loss of sugar portions from the grains, and prevention of the complete enzymatic activity that converts the grain starches to sugars. Ultimately, due to the inconsistency of the roller mill finished particle size, only 87% of the possible 98% grain efficiency was achieved. As a result, Tin Man was required to add approximately 10% more grain to their beer recipes to achieve the desired quality.

 tin man brewing company. grains

Roller Mill Out, Hammer Mill In

Unlike roller mills that reduce materials by compression, a hammer mill reduces by impact. A hammer mill is essentially an enclosed steel container, housing a rotor which spins at very high speed.  Flat steel hammers are attached to the rotor. As the rotor spins, the hammers flail out, and repeatedly impact material in the grinding chamber until it is able to pass through the steel mesh screen covering the mill’s discharge opening. Finished particle size is determined by a combination of rotor speed, hammer size, hammer configuration, and screen size.

In effort to solve their issue with finished particle size consistency, Tin Man purchased a Schutte- Buffalo Hammer Mill Model 18-7-301B Circ-u-Flow hammer mill. Custom configured to suit their specific materials, and production goals, the mill features a 10 hp motor, abrasion resistant steel hammers, and a 1/8” screen. 

The model 18-7-301B is a full circle screen hammer mill with 300 degree screen coverage of the rotor,  compared to  the 150 degree screen coverage seen in more traditional industrial hammer mill models. This means the properly sized material has a larger area to evacuate the grinding chamber. As a result, the full circle screen hammer mill has the highest throughput to horsepower ratio of all hammer mill styles.

model 187301b full circle screen hammer mill

O’Rear reports that following the hammer mill installation, the process improvements were instantly remarkable. The grains were processed to a very fine, consistent finished particle size with no additional milling time required, and thus no impact on labor. The resulting mash was much less viscous, and the loading of the mash filter was fast and easy, with no backups.

 Immediate Impact

The first beer produced from the hammer milled grain using the old grain weights came out with significantly higher sugar loads than the beers produced with the same weight of roller milled grain. According to O’Rear, the efficiency went from 87% to 94% immediately! As a result, they are able to reduce production costs by dropping grain amounts by 8.5%.

 tin man brewing company

“We will continue to optimize the system to achieve 98% mash efficiency, but no other improvement will have as large or as immediate an impact as our Schutte-Buffalo hammer mill.”

Sean O’Rear, Head Brewer
Tin Man Brewing Company


 

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Topics: finished particle size, hammer mill, full circle screen hammer mills, size reduction, brewing grains, grains, grain efficiency

Hammer Mill Application Focus: Grinding Grains for Animal Feed

Posted by Cassie Brown

Mar 29, 2013 9:37:00 AM

Producers of animal feed all know a simple truth: when processing cereal grains for animal feed, finished particle size matters.  A lot.corn before and after hammer mill processing

Blendability, and digestibility – even the economics of feed production – are all affected by the finished particle size of the grains.  But this is not a one-size-fits-all situation.¹  The ideal finished particle size varies by the grain being processed, and depending on the species, the life stage of the animal.²  With all of this in mind, selecting the proper method of size reduction is a critical decision.

 

Roller Mill or Hammer Mill

Unlike the angular shaped particles produced in a roller mill, the pulverizing action of the hammer mill results in particles that are more rounded. These smoother surfaces make it easier for the grains to be blended with other components of the feed.²

 

So Many Hammer Mills

A hammer mill is essentially a steel box surrounding a rotor. Swinging hammers attached to the rotor, flail out when the rotor spins. A screen covers the discharge opening to regulate the finished particle size.

As material enters the hammer mill, it is pulverized by a combination of hammer blows, particle on particle contact, and impact with the walls of the hammer mill. The material remains in the grinding chamber until it is able to pass through the screen covering the discharge area.

But those are just the basics. There are myriad styles of hammer mills: industrial mills, full circle screen hammer mills, horizontal grinders, tub grinders, and more.  As for size, hammer mills can range in size from 6” to more than 60” rotor widths.  Choosing the right hammer mill for your purposes depends greatly upon the material you are processing, and your production goals.

 

The Full Circle Solution

The design of the full circle screen hammer mill makes it the ideal method of size reduction when processing cereal grains for animal feed.  Let’s take a closer look:

Throughput

With swine operations reporting that up to 75% of their budget is allocated for feed production,³  the need for energy efficiency cannot be overstated.

As its name suggests, the full circle screen hammer mill differs from the traditional industrial hammer mill because it has nearly double the screen coverage of the rotor:

 screen coverage for full circle screen hammer mill                       screen coverage for industrial hammer mills                                     

    Full Circle Screen Hammer Mill                                 Industrial Hammer Mill

                                                                  

The greater screen coverage of the full circle mill means that there is more area for the material to evacuate the grinding chamber. As a result, a higher throughput rate can be achieved at a lower horsepower in comparison to industrial hammer mill models.  

Particle Size Flexibility

Precision and consistency of the finished particle size has a strong effect on the digestibility of the feed.  A finished particle size that is either too large or too small will have adverse effects on animal performance.²

The primary factor determining finished particle size is the measurement of the perforations in the screen covering the discharge area. The size of these perforations is equal to the maximum finished particle size of the material processed.

The ideal particle size range of 650 to 750 microns³ can easily and consistently be achieved through proper screen selection. In addition, screens can easily be changed to accommodate the processing goals of a variety of grains using the same hammer mill.

The secondary factor in determining finished particle size if the speed of the hammer mill. When the rotor spins, the hammers flail out and impact the material with great severity causing it to break down.  As a result, the higher the rotor speed, the greater the number of hammer mill blows, and thus a finer end product.  An optional component for the full circle screen hammer mill is a variable frequency drive electrical control. This control panel allows the operator to raise or lower the rotor speed as needed for different applications.

 

Summary

The pulverizing action of the hammer mill produces a finished particle that is easily blendable. The nearly 360 degree screen coverage of the full circle screen hammer mill allows for the greatest throughput to horsepower ratio of all hammer mill designs. A consistent and precise finished particle size can be achieved by screen selection. Finally, the ability to change screen size, and the option of a variable speed frequency drive control, enable processing a variety of grains using the same hammer mill.

 

References

¹ Steinhart, Terry L., Iowa State University (2012). Swine Feed Efficiency: Influence of Particle Size. Retrieved from  http://www.swinefeedefficiency.com

²Pork Production in Mississippi is Particle Size Important for Swine Diets?(2013). http://www.msucares.com/livestock/swine/particle.html

³Sayler, Julie. (2012). Small Particle Size Makes a Big Difference.http://swineperformance.vitaplus.com/2012/04/small-particle-size-makes-a-big-difference/  

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Topics: finished particle size, full circle screen hammer mills, variable frequency drive, size reduction equipment, corn, animal feed, cereal grains

What are the Benefits of Pneumatic Discharge in Size Reduction?

Posted by Cassie Brown

Nov 5, 2012 8:37:00 AM

Size Reduction 101

Hammer mills of all shapes and sizes process material with the same basic pulverizing action. Rectangular steel hammers are attached to a shaft inside of a steel grinding chamber. As the shaft spins, the hammers flail out bringing them into contact with the material being processed. A combination of hammer blows, particle on particle impact, and contact with the mill’s interior work in unison to reduce the material until it is able to pass through the screen covering the mill’s discharge opening.

 

Evacuation Options

Once the material is reduced to the desired finished particle size and passed throught the screen, there are two options for how it exits the mill. The method is determined by the material's characteristics. If the material is:

 gravity vs pneumatic discharge graphic

 

How Does Pneumatic Discharge Work?

It's all about the fan. Air swept mills are used primarily when grinding light, relatively non-abrasive materials to a mid range to fine particle size because lighter particles require suction to overcome the rotor airflow. The fan pulls the material from the mill in-feed through the grinding chamber. In addition, it pulls the finished product through the suction pipe, into the fan itself, and then blows the material out of the discharge pipe either to storage or next stage grinding.

 

pneumatic discharge hammer mill diagram

Why Choose Pneumatic?

There are three key benefits:

  1. A properly designed pneumatic discharge system can increase production 300-400% over gravity dischage mills when grinding light materials to a fine particle size.
  2. Without air, dusty material will take the path of least resistance, typically out the feed chute. In a pneumatic system, dust is controlled and contained because all material is pulled in a common direction.
  3. The fan also aids in material transport to storage or next stage processing.
Bonus advantage:
The ability of the fan to pull the material through the screen allows for processing of materials with slightly higher moisture content than can be effectively processed via gravity discharge.
Download our Fact Sheet:
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Topics: particle size, particle on particle contact, hammer mill design styles, gravity discharge industrial hammer mill, pneumatic discharge hammer mills, air assist, low density materials, abrasive materials

Full Circle Screen Hammer Mills: Low Horsepower, High Throughput

Posted by Cassie Brown

Jul 20, 2012 12:59:00 PM

high production full circle screen hammer millSize reduction equipment comes in a wide variety of shapes and sizes: vertical or horizontal hammer mills, jaw crushers, roller mills and ram-fed grinders, just to name a few. For the most part, the size and shape of the mill/grinder/crusher plays a key role in the functionality of the machine, and for the applications it is best suited for. Nowhere is this truer than with the Full Circle Screen Hammer Mill.

 

A Peek Inside...

The full circle screen hammer mill gets its name from the 300 degree screen coverage of the rotor, while all other styles of hammer mills typically have closer to 180 degree coverage of the rotor. 

describe the image                    

 Full circle screen hammer mills                                 

 

Ideal Applications

To achieve the circular, nearly full coverage of the rotor requires that the screen be somewhat pliable, and therefore relatively thin. In addition, the full circle screen mills use thin, notched hammers that reduce material with a tearing/grinding action, as opposed to the pulverizing effect of the large, heavy hammers often used in the industrial hammer mills. As a result, the full circle mills are best suited for light, easy to grind materials that do not require initial grinding against a breaker plate. 

Some examples include:

 cuf application.wordle resized 600

 Size Reduction 101

When material enters the grinding chamber, it is repeatedly struck by hammers that flail out as the shaft spins.  A combination of these hammer blows, particle on particle impact, and impact with the walls of the grinding chamber all work together to break the material down. The material remains in the grinding chamber until it is reduced to a size that will pass through the screen. 

The larger the screen area, the greater the opportunity for the material to evacuate the mill. As a result...

 full circle mills.throughput

 Additional Considerations

Once you have decided that the full circle screen hammer mill is best for your material, determining the following criteria will ensure so that the mill is configured to meet your production goals:

  • Material being processed -  Material characteristics such as: friability, flowability, moisture content, and infeed size
  • Desired finished particle size  - Sawdust, granules, coarse or fine powder?
  • Desired production rate - 10 lbs/hr, 10 tph, etc.

With this information, the following can then be determined:

  • Hammer mill size - Rotor diameter and internal mill width.
  • Hammer size and style - Number of hammers, size, style and metallurgy.
  • Screens  - Style and thickness of screen, and size of openings.
  • Choice of proper RPM
It's Optional
Finally, once the the mill is configured, the last determination is whether or not any optional peripheral equipment is needed. For this, the following questions must be answered:
  • How will the material be fed into the mill? By hand, auger, or belt conveyor?
  • How will the material be taken from the mill? Gravity, air assist, or full air evacuation?
  • Is dust a concern?

Answers to these questions will help to determine the best types of optional equipment such as belt conveyors, augers, rotary feeders, and dust collection, as well as the most efficient design of the infeed and discharge chutes.  

 

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Topics: full circle screen hammer mills, particle on particle contact, biofuels, briquetting, bio-fuel applications, circular hammer mill, corn, animal feed, corn meal, corn flour, hammer mill design styles

5 Reasons to Choose a Hammer Mill for E-Scrap Recycling

Posted by Cassie Brown

May 18, 2012 3:50:00 PM

 

Challenging the Industry Standard

In earlier posts we discussed how the simplicity of hammer mill technology lends itself well to many applications. On occasion though we encounter an application where the hammer mill is not only effective, it far exceeds the industry standard. E-scrap processing is one of those areas.

Traditionally, whether the goal is data destruction, recycling of materials - or both, e-scrap has been processed in large industrial shredders. Shredders process the e-scrap by using a shearing action that cuts the material as it passes through claw-like knives. While this is method is effective, drawbacks include frequent maintenance to replace the shredder knives, and the costly price point of the standard industrial shredder.

Hammer Mill 101 

Hammer mills process material with a pulverizing action. Rectangular steel hammers are attached to a shaft inside of a steel grinding chamber. As the shaft spins, the hammers flail out, bringing them into contact with the material being processed. A combination of hammer blows, particle on particle impact, and contact with the mill interior, work in unison to reduce the material until it is able to pass through the screen or heavy bar grate covering the mill's discharge opening.

A Better Mousetrap 

Now let's look at that process as it relates to e-scrap processing, to see how it is more efficient and effective:

1. Flexibility - The simplicity of the hammer mill design offers great flexibility, making it suitable for processing a wide variety of e-scrap materials down to the exact desired finished particle size. Mill size, hammer style and configuration, and screen size are determined based on the processor's production goals. In fact, multiple types of e-scrap media can be processed in the same hammer mill, without reconfiguration.

hard drives

2. Complete Data Destruction -  As it is pulverized, the e-scrap material is continuously scraped and scoured by the turbulent action within the mill. As a result, all retrievable data is destroyed.

smartphones3. Liberation of Metals and Other Materials - The second benefit of the pulverizing process is that the hammering action breaks the e-scrap apart, liberating the metals and various other materials. Once broken apart, all pieces remain in the grinding chamber and continue to be pulverized until they are able to pass through the screen covering the mill's discharge opening.

printed circuit boards 

4. Low Cost, High Production - Hammer mills are available in a range of sizes, and are highly customizable based on the material(s) being processed and the user's production goals. A mid-sized hammer mill configured for computer hard drives can process up to 2500 units per hour. A shredder with the same throughput capacity would cost roughly four times that of the hammer mill. 

5. Minimal Maintenance -  The knives of the shredder dull quickly, and in many cases must be changed monthly. In comparison, one set of 4-way reversible hammers will, on average, last up to one year.

For more information, download our new eBook:

hammer mills for processing e-scrap ebook

 

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Topics: hammer configuration, hard drives, hammer mills, shredders, de-manufacturing electronics, e-scrap, data destruction, recycling, smartphones, printed circuit boards

Hammer Mills: 5 Key Styles You Need to Know About

Posted by Cassie Brown

Apr 12, 2012 3:50:00 PM

 

You Need a Hammer Mill for That…

So, you have a material that you would like to make smaller for a given purpose. Sounds simple, right?  Well, in most cases it is. However, there are a number of considerations that must be made to get you to the finish line in the most efficient and  most economical way.  

But First a Little Background

Hammer mills are just one type of machinery among the much larger category of size reduction equipment that also includes:  shredders, jaw crushers, ram fed grinders, roll mills, ball mills, and more. Looking a bit closer, even within hammer mills, there are several styles to choose from. Among those styles, the functionality of a hammer mill remains basically the same:
  • Material is fed into a grinding chamber
  • Contact with moving hammers, and interior mill components reduce the material’s size
  • Material remains in the hammer mill’s grinding chamber until it is able to pass through a screen or grate with certain size openings.
The following is a comparison of five key styles of hammer mills:

 

Gravity Discharge Industrial Hammer Mills

Industrial hammer mills have the simplest and most recognizable funtionality. A rectangularindustrial hammer mill steel chamber houses a shaft to which swinging hammers are attached. As the shaft rotates at high speed, the hammers flail out impact the material. In addition to the hammers, size reduction occurs through particle on particle contact and through contact with the breaker plate inside the grinding chamber. Because of their simplicity, the industrial hammer mill is easily adaptable to different sizes and milllab scale hammer mill  designs.
Important to know: Replaceable steel liner plates protect the mill's interior from wear caused by grinding abrasive materials.
Ideal Applications: glass, coal, coke, dry chemicals, metals, resin, porcelain, aggregates, brass, ceramics.
 

 

 

Pneumatic Discharge Hammer Mills

The grinding mechanism of this group is quite simliar to the gravity discharge hammerhigh production industrial grindermills. However, the pneumatic mills typically use a thinner hammer and the interior wall of the grinding chamber features a ribbed liner plate. This plate has a washboard effect on the material, and works in unison with the hammers and particle on particle impact to reduce the material. finish grinding hammer mill with integral fanThe biggest difference of course is the group's the use of air assitance to evacuate material from the mill. Whether attached to the main mill shaft, or as a separate optional component in a high production model, the fan pulls the the material through the mill, and conveys it to storage.
Important to know:  Specially designed notched hammers are ideal for tearing and shredding. In addition to assisting the evacuation of  light or low density materials, the pneumatic suction can increase throughput up to 400% over gravity discharge hammer mills. 
Ideal Applications:  hogged wood scrap, wood chips, green wood, biomass, paper, carpet, meat and bone meal 

 

Full Circle Screen Hammer Mills         

This next group also features the same grinding mechanism as the first two, and the same thin hammers as the pneumatic hammer mills. The amount of screen coverage is what sets the full circle screen hammer mills apart.  
high production full circle screen hammer mill The nearly 300 degree coverage of the rotor translates to a greater surface area for the processed material to evacuate the grinding chamber. As a result, compared to the industrial mills, you get greater throughput per horsepower with full circle screen hammer mills.
diagram of circ-u-flow screen coverageImportant to know: To achieve the circular, nearly full coverage of the rotor requires that the screen be somewhat pliable and therefore relatively thin. Because of this, the full circle screen mill is best suited for light, easy to grind materials to that do not require initial grinding against a breakerplate.
Ideal Applications: corn, grain, spices, grasses, planer shavings, sawdust

 

Horizontal Infeed Hammer Mills

The unique quality of the horizontal infeed mills is that material is fed into the side of the hammer mill, instead of the top. This design makes them ideal for long, linear or horizontal trim scrap grinderotherwise large, geometric materials to be processed with out a pre-grind. This group includes trim scrap grinders and pallet grinders. As with the prior styles, the horizontal mills use heavy duty screens covering the discharge area to determine finished particle size.
Important to know:  the style and design of the hammers aggressively moves the material into the mill. Feed rolls are ideal to properly control the rate that material enters the grinding chamber.
Ideal Applications: trim scrap, truss palnt scrap, 2x4s, whole pallets, pallet scrap

  

Lumpbreakers

The Lumpbreaker is quite different from the prior categories in both designsingle rotor lump breaker and functionality. Instead of swinging hammers attached to a shaft rotating at high speed, the lumpbreaker has stationary hammers attached to a slower moving shaft. As the shaft rotates, the hammers remain rigid, and pass between combs attached to the wall of the grinding chamber. Lumpbreakers do not use screens for sizing. Instead, the configuration of spacing between the hammers and combs, along with hammer size and RPM allows some control over the finished particle size.
Important to know: The open infeed, fixed hammers and slow shaft rotation give the lumpbreaker the ability to accept a certain amount of a headload, making it suitable for large blocky materials, de-agglomerating, de-lumping, and returning materials to a flowable consistency.
Ideal Applications: sugar, cement, dry chemicals, agglomerated powders

Broad Categories

For the purpose of this post we broadly examined five of the more common styles of hammer mills. It is important to note that each of these categories could be further broken down to highlight the scope of its variables.

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Topics: full circle screen hammer mills, particle on particle contact, size reduction equipment, industrial hammer mill, hammer mills, hammer mill design styles, gravity discharge industrial hammer mill, liner plates, pneumatic discharge hammer mills, ribbed liner plates, air assist, low density materials, abrasive materials, horizontal infeed hammer mills, trim scrap grinder, pallet grinders, feed rolls, stationary hammers, hammers and combs, deagglomeration, delumping

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