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HOW TO CHOOSE THE RIGHT LUMP BREAKER DESIGN
Friday, June 16, 2017
Lump breakers are commonly used in the food and chemical processing industry; thus the need to know the right lump breaker design suitable for your industry use. They are often used to break up lumpy product that has formed during storage. It is typically found in the following operations:
Discharge point of raw materials
Manual bag emptying stations
Discharge point of storage silos or containers
In this article, we'll give you tips on how to choose the right lump breaker design for your industry needs. However, let us begin by understanding some basic facts about lump breakers.
What are the different uses of lump breakers
Lump breakers are used for the following processes:
Preparing your material for conveying
Breaking up agglomerates
Reducing the material for further processing
What materials require the use of a lump breaker?
Lump breakers reduce the lumps and agglomerations in various powder and grains which can impact and impede product flow. These include:
A typical lump breaker is composed of the following:
Rotating shafts
Stationary combing bars
Housing Weldment
Reducer
Motor
Parts of a lump breaker
In addition to these, most lump breakers have a fixed grate and one or two sets of rotating blades designed with different speed options. These have a self-cleaning design with very small dimensions that can easily be inserted into existing systems. As needed, it can be installed as a stand-alone component which is normally located immediately above the vessel or incorporated within an existing plant layout and system for discharge.
How does a lump breaker work?
Lump breakers work in the following manner:
The two rotors equipped with a range of blades impact the lumps and force the material through the fixed grate. The width of the grate opening determines the maximum size of material allowed through. These blades and rotors also follow a rotating movement, which pushes the material to the centre of the machine. This motion then adjusts, grinds and crushes the material.
However it is noteworthy to remember that these blades are designed to both impact the product and “drag the material through the grate to avoid product blockage.
This video shows how it is done:
How to find the perfect lump breaker design for your industry use?
There are many lump breaker manufacturers in Australia and around the world. But how do you find the perfect lump breaker design for your industry use? Here are some of the guidelines to consider:
Application parameters when finding the perfect lump breaker design
Before proceeding into buying a lump breaker for your industry needs, it would be best to know the following characteristics of your materials.
Bulk density information
Bulk density is the material's response when it comes into compact under various loads. It is also an indicator of flow. It is dependent on its consolidation strength, the ability of the materials to compress.
Coarse powders and dry sand are not compressible giving these materials a lower bulk density compared to other fine grained materials that can be easily compressed.
Granulated sugar is classified as an easy flowing material whilst confectionary sugar is a fine, cohesive material. Thus if you fill a container with granulated sugar and hit a hundred times in an effort to compress it, you'll see very little compression in the accumulated material. That is because the voids between the particles remains unfilled due to the coarseness of the material.
Do the same with confectioner’s sugar and observe how easily it fills in the voids.
Why is this important in choosing the right lump breaker for your industry use?
Based on the bulk density information, you can determine how compressible the material is and how many bags can be fed into the lump breaker.
Moisture content
A material with high moisture content can easily overwork the crusher due to its gummy and sticky feature. Understanding this will help you adjust with the amount of energy to input into the material by varying the following factors:
Rotor tip speed
Tooth design
Tooth quantity
In doing so, this will help minimise problems associated with high moisture materials.
Consistency and fiber content of materials
Fibrous materials can be challenging to crush, but by selecting the proper tooth or blade design, screen or comb tooth configuration and rotor tip speed, this can be very much possible. Talk to us if you are dealing with these challenges.
Heat-sensitivity of the materials
Heat-sensitive materials are quite tricky to crush. One of the ideal solutions for this is to:
Add a cooling material to the product
Control the operating speed of the lump breaker
Choose an internal contact component like a comb teeth rather than a screen
Nevertheless, using a pneumatic conveying system to draw ambient or chilled air through the crusher can be the best options. Talk to us about it.
Process parameters when choosing a lump breaker design
These process parameters ensures your choice of lump breaker design will help you achieve your desired particle size and consistency.
Particle size distribution
This includes the percentage of lumps against the free flowing material as it enters the lump breaker.
Entry flow into the lump breaker
It is important to identify how the material is being fed to the lump breaker. Is it by surging, controlling and metering, or flood feeding?
Exit flow from the lump breaker
For materials that have small percentage of lumps and large percentages of fine grains, an efficient way of separating these fines is through a gravity screening transition.
The screening process will filter the fines so it can directly go to your process line, while the oversized material gets into the lump breaker. These easily helps draw the material out of the crusher discharge while preventing over grinding of the material.
The location where the lump breaker is to be installed has a big impact on its operation, specifically its relationship to the feeding and discharge device.
Feeding device
The common misconception is for the crusher to be mounted directly under a bin so it can serve as a feeding device for the process. However, this is not the case because doing so creates a head loading to the feeder.
If you carefully observe a lump breaker's rotor design, it will easily reveal that mounting the lump breaker so material flows from the bin and down around the rotor will easily fill its housing. This puts an excessive load on the rotor(s) because there is no room to move or to displace the material during rotation.
What is a better approach to this?
Try metering your material to the crusher with a device such as a belt feeder or screw feeder to achieve a more consistent and efficient lump breaking action.
Discharge device
Your chosen discharge devices should remove the material from the lump breaker as fast as the feeder meters material into the crusher, which is 1.5 times the feed rate. This prevents the material from backing up into the lump breaker at the discharge which is the cause of over grinding.
Material back-up
Another reason for a crusher drive overload is the material back-up at the discharge. It can be likened to a the lump breaker being twisted into a spade that's driven into a barrel of sand due to the additional head load put into it.
Lump breakers take tremendous torque to handle head loads. Thus a need for a larger lump breaker or crusher to handle it.
Metal choice for your lump breaker design
Lump breakers are usually welded or bolted and available in:
Carbon steel
Stainless steel
Cast Iron
Abrasion resistant steel
Aluminium
Castalloy
Titanium
Here are the following recommendations based on the industry type:
Bolted or welded carbon steel - agricultural applications
Stainless steel - food, dairy and pharmaceutical applications
Chemical and resins - aluminium and titanium
Pneuvay Engineering provides stainless steel lump breakers which are ideal for the reclaim systems within the food processing industry. It is most suitable for light-medium duty. Learn more about this product here.
