Selecting the right Crusher to Rent or Buy is critical because the right machinery can help increase productivity and reduce downtime – which of course translates to higher profitability and quicker completion of your project.
Material may need to go through several stages of Crushing and Screening before achieving the desired end-result.
How to Choose a Crusher?
When choosing the right crusher for you, there are several factors to consider. You will have to choose from the three key crushers available on the market: Mobile Cone Crushers, Mobile Jaw Crushers and Mobile HSI Impact Crushers. Each one of these crushers come with their own unique set of pros and cons in different applications. This does not mean that one crusher is better than the other. Rather, the list of pros and cons help with decision-making, helping you narrow down your choices and zero in on the crusher that will yield the best results for your project and its scope.
Some of the key factors to consider when purchasing or renting a crusher include:
What point in the process the crusher will be used – Primary, secondary or tertiary crusher?
- A primary crusher is best suited to reduce material: from 900 to 300mm, a secondary crusher is typically suited to crushing 300 to 100mm rock and a tertiary crusher is ideal for finer crushing producing fractions below 30mm
- The Level of Abrasiveness and Hardness of the Material Being Crushed: Different crushers are designed to withstand varied levels hardness or abrasiveness of materials. It is very important to choose a crusher that can handle the material you aim to crush. Abrasive rock can increase wear on crusher parts, and add to the expense of running the machine. Hard abrasive rock can include granite and quartz, softer less abrasive rock can include dolomite and limestone.
- The Size & Dimension of the Material Being Crushed: Not only do you need to consider the size of the crushed material, but also the size and dimensions of the material being put into the crusher. The feed material needs to be less than 80% of the gape which is the greatest distance between the two crushing sides. Other factors to consider when examining the feed material is how it will break and what shape will be produced along with the amount of fines.
- The Required Product Size: the end product size will depend on the type of crusher you use and the CSS Closed size setting you are able to achieve
- The Processing Capacity/Throughput: Whatever project you are working on, you will have a required throughput to ensure you have the amount of material processed on time. This is measured in tonnes per hour. “Proper production capacities are critical to the success of a business. A crusher that is too small fails to produce the desired tonnages, which limits yields and profits and caps the organization’s growth potential. A machine that’s too large carries extra expense with no added value.”https://www.pitandquarry.com/selecting-the-right-crusher/
Cost and quality of wear parts:
- The Cost and Quality of Parts Can Vary: this can be due to a number of factors such as the material used in the parts including manganese, steel, chrome or ceramic, if they are genuine parts, and the quality of manufacture.
Ease of maintenance:
- Some Jaw Crushers have Removable Engines: which can ensure that when located remotely from the crushing plant it will reduce dust and vibration levels, as well as facilitate easy maintenance access.
- Some Jaws Have a Reversible Jaw Drive: that allows material like asphalt to be 'fluffed' and in the case of oversized or sticky material; quickly unblock the unit and continue crushing. Both of these features assist in managing WHS.
- Some crushers are designed to be more mobile: The mobility of the crusher is more than just the speed. It is also the ability to maneuver in small spaces. Mobile crushers are mostly available as tracked equipment, they are designed to turn within their own footprint, travel from side to side and have a lower centre of gravity ensuring more stability. Mobile crushers can also come wheeled and are suitable for certain applications such as asphalt and hard concrete.
The Key Crushers on The Market – Which One Should You Choose?
Going through the pros and cons of each crusher will help you make a well-informed decision when considering crushers for rent.
Mobile Jaw Crusher
Jaw Crushers are predominately primary crushers. They are used to crush hard material such as rock, ores, granite, recycled concrete and more.
They consist of a fixed plate, a swing plate (called jaws), and it is between these that rock is trapped and crushed. Both sides are replaceable as well as the side liners or cheek plates. The typical reduction ratio is 5:1 - 7:1. Minimum CSS closed sized setting is 75-90mm
- Handle large feed size
- High production
- They are low maintenance.
- Often less costly to operate due to minimal moving parts
- They are comparatively rudimentary and so, not difficult to use
- Is mainly suitable for hard material, not soft or mixed material
- Has a limited reduction ratio (however can be used in combination with other crushers if required)
- Depending on the rock type the jaw may not give the best shape
Mobile Cone Crusher
Cone Crushers (Conical Crushers) are a popular choice for secondary crushing. The outside of the chamber is called the concave and is fixed, inside the chamber is the rotating shaft called the Mantle. The Mantle rotates and moves in an eccentric circular motion crushing the rock against the concave. As the rocks break they slide down the chamber and continue to be crushed by the mantle until they are small enough to pass through the opening at the bottom.
- Good product shape especially if the reduction ratio is lower
- Accepts most types of feed material
- Reasonable reduction ratio
- They are designed as a secondary crusher
- Can be more expensive
- Is mainly suitable for hard material, not soft, clay or mixed material such as concrete feed material or metal mixed with rock
Mobile Impact Crusher
Impact crushers can vary from primary crushers, secondary crushers to tertiary crushers depending on the technology and size of the model. They use high impact to crush material, being equipped with a high speed rotor with blow bars or hammers that throw the rock against the breaker plates. The blow bars hit the raw material which lands onto the breaker plates, before bouncing back up and continuing the process until the material is small enough. Impact Crushers generally come as either Horizontal-shafts or Vertical-axis.
- They can crush a variety of material such as clay, dirt, soft materials and more.
- Better quality shaped product produced
- High reduction ratio
- Can be used as a primary crusher to produce final product
- Produces large amount of fines
- Accept contaminated materials
- Different blow bars can be chosen to best suit the application. These include Manganese, Chrome and Ceramic, which have different wear qualities.
- Can be more expensive
- Higher wear rate especially in abrasive rock
- Large pieces of steel will cause substantial damage
- Good dust suppression will be required
To get the most out of any crusher you choose, consider prescreening your material to ensure the feed is relatively uniform and then choke feed the crusher. Greater production will be achieved if the material is fed in a consistent manner without start stop operation in order to give better shape and better reduction, with less wear and tear.
To find out more about which crusher would suit your application, speak to one of our trained consultants, contact Bost Group today at 1800 267 847.