Cone Crusher Liners

In the current economic climate, decreasing cost and increase profit are the most important, and cost base is a major factor in managing a successful quarrying business, crusher replacement costs associated with cone crushers can be a major cost center. This post explains a method to reduce crusher replacement costs by casting crusher liners. However, the process has been perfected in recent years and can work well in the right applications. Cone crushers operate by having stone fed into the top of the crusher chamber. The chamber is lined with crusher replacement, namely the mantle and bowl liners. As the stone drops through the choked chamber, crushing is achieved when the motion of the mantle causes compressive and abrasive forces to act upon the stone and bowl liner, causing the stone to break. Liners are manufactured from manganese steel rather than normal steel as the manganese content provides protection against abrasion (normal steel generally has a lower tolerance to wear than crushing duties require). Depending on the stone being crushed, the percentage of manganese in the liners can vary from around 12% to 23%, so we can find the materials Mn14, Mn18, and Mn21. Below are the major factors we need analytics:

Liner selection

When selecting a crusher the bowl liner also varies in type:

• Coarse: wide inlet aperture
• Medium: medium inlet aperture
• Fine: small inlet aperture

Once again, selection depends upon the product required and the feedstock. Consultation with manufacturers is essential, some of whom will provide computer design facilities and offer wear-analysis services on both their own and other makes of crusher, such as the level of competition.

Crusher selection

Correct crushing chamber selection is crucial when installing a cone crusher. The reduction ratio, which in turn determines the product produced, depends on the chamber selected. In addition, the closed-side setting (the gap where maximum crushing is attained) affects both wear and the product produced. For example, if a standard unit is used instead of a short head, a reduction in fine product occurs, resulting in recirculation and, hence, more wear. The characteristics of the main types of the chamber are Standard: shallower angle than a shorthead with a longer crushing face. Suitable for larger feed sizes, generally +100mm, with a wide feed grading curve. Suitable for use as a secondary crusher but, if the smaller feed is introduced, can become susceptible to packing/blockages. Shorthead: steeper angle than a standard with a shorter crushing face. Suitable for smaller feed sizes, generally –100mm, with a short feed grading curve. Suitable for use as a tertiary crusher but will not accept large feed size owing to its smaller feed aperture.

Add protective surface

In order to prevent liner wear during the initial period of work-hardening, specialist contractors can coat the liners with a protective surface. This process has to be carried out with great care because the manganese liners can distort and/or shrink during the process, causing a poor fit in the crusher. Small distortions are generally not a problem in crushers using the backing compounds, as the backing material compensates for any such irregularities. To apply the protective coating, the liner is placed on a rotating turntable and carefully preheated. A bead of 3 mm thick chrome carbide is welded onto the liner as the table revolves. The areas requiring treatment are determined by the wear pattern on a normal set of liners, and by experimenting with resultant wear patterns on treated liners.

Cone crusher liners that exceed their intended operating life will cause mechanical problems with the crusher. A liner that is pushed too long will flex and crack, and the flexing of a thin or cracked mantle will cause severe seat surface damage.

Although there is no foolproof way to tell when the liners are worn out, here are Three indications it is time to change the liners:

1. Production level

When you see a 10% or more drop in production level or throughput, it is a good indication the Cone Crusher liners need to be changed.

2. Liner thickness

If the liner is wearing evenly throughout the chamber, you should consider changing it when it has worn down to about 1” (2.5 cm) thick at the bottom. At about 3/4” to 5/8” (1.9 cm to 1.6 cm) thick, the liner will crack, causing the backing material to begin to disintegrate. This will cause the liners to break loose. If the liners break loose, the continued operation could destroy the seat on the support bowl or the head of the Cone Crusher.

Some Cone Crushers feature an automatic liner change reminder. When new mantle and concave liners are installed, the automatic reminder is reset. As the crusher operates, the system tracks production capacities and calculates the liner wear rate. When the cone liners reach the maximum wear point, the system sends a flashing reminder to “Change Cone” on the cone setting meter. After the wear parts are changes, reset the automatic reminder system and continue efficient and reliable crushing.

An important item to note: You should never place a new concave liner in a crusher with a worn mantle or a new mantle in a crusher with a worn concave liner. Mating new and worn components will change the profile of the crushing chamber and restrict the feed from entering the crushing chamber, which will reduce the tons per hour produced.

3. Change the liner before you start to suffer significant production losses.

On top-adjust/screw adjust cones this is especially true as the feed size starts to shrink pretty dramatically as soon as you get to the last 1/3 of life and as you near the end the feed size can get very small, losing as much as 30% of feed size. This is less of an issue with hydrocones as the feed size remains constant throughout the life of the manganese.

You should have a pretty good idea when you will need to change manganese and be able to have all of the parts on hand prior to needing to change. By having an accurate belt scale, you can know to the day when your production starts to tail off to the threshold and schedule the change immediately.

What is the threshold for a liner change? We believe the maximum threshold for a liner change is as follows: Change your liners no later than a 10% decline in production.

Why?

Production rate: 200 tons per hour of sellable? minus Crush Margin $2.50 per ton hours per day 10 production hours per day.

Therefore a 10% reduction in production results in a loss of $2,000 per day in gross profit. All of the other fixed and “variable” costs of labor and fuel keep adding up at the same rate. At $10,000-12,000 per week it doesn’t take too long to rack up serious losses, in two weeks you could afford at least two new sets of liners!

Some may say that times are tough and we can’t sell everything we can produce so why not get the last ton out of that set of manganese? If you conduct four liner changes per year and you delayed each change by two weeks, you add forty-four hours of operation time to your season, that’s a whole week of wages and fuel!

Simple, have an accurate belt scale, plan your liner change and do it no later than when you notice a 10% decline in production.

Normally, there are 6 steps to change cone crusher liners:

1. On the first collection of brand-new linings, position a mark on the modification cap chauffeur ring where the pinion tooth reaches a motorist ring tooth when the target crusher setting has actually been accomplished.
2. Keep an exact document of the number of teeth made use of to compensate for lining wear on this collection of linings.
3. After the first collection of linings have worn out, but before relocating the dish, record the complete number of teeth the driver ring has actually relocated as well as also repaint a straight lining on the side of the dirt
4. covering just listed below all-time low of the changing cap. This will be the standard for determining exactly how close the next liner collections are to being worn.
5. When a new liner set has been installed, keep a document of the number of teeth the driver ring has relocated and compared this number to the overall number from the first collection of linings. This will give an evaluation of the liner wear.
6. The horizontal mark repainted on the dust shell will additionally be suggested when the linings are coming close to the wear restriction. The approximate minimum heights of the changing cap (A-dimension) with used linings are provided in the affixed tables.

There are 5 key points that you need to consider when selecting the correct crushing chamber:
1. Feed size
Each chamber configuration has a maximum feed size that it can accept.
2. Feed grading
The maximum feed size is important as if there are a lot of fines in the feed or a lot of single size in the
feed, it can cause issues with wear and output.
Attention should also be given to recirculating stone for the following reasons: It has a tendency to be a lot more abrasive and harder than virgin stone; Depending on the amount recirculating, it can cause issues with segregated feed
3. Output required
This takes into account output and grading required, which can affect which crushing chamber you
should select.

4. Crusher adjustment (CSS)

The closed side setting (CSS) defines the reduction ratio in cone crushers and has a significant effect on product gradation, capacity, and power draw. The closed side setting is measured from the bottom of the mantle to the bottom of the bowl liner at their closest point during the gyrating cycle.

CSS should be close to the required product. The setting is too small if the adjustment ring is moving on the mainframe.

5. Crusher operating speed (RPM)

Generally, a higher speed creates a finer product gradation curve and better product shape, which is important when producing the end product for most construction applications, while operating the cone crusher at the lower end of its speed range will increase the cavity volumetric throughput and the product gradation curve can be altered to produce fewer fines. The Crusher operating speed is adjusted by changing the diameter of the crusher and motor sheaves.

Each cone crusher has several cavity options with different feed openings and setting ranges. The correct cavity can be selected based on the feed size, setting, and application. Overall, it is essential to keep in mind that the crusher is just one part of a crushing circuit. Its performance depends on the proper selection and operation of feeders, conveyors, screens, electric motors, drive components, and feed silos which are part of the circuit. All the elements should be examined as part of an entity to get the most out of the production.

Normally, cone crusher liners are cast by sand casting. The standard cast steps as the followings:

Step 1: Check the drawings with the customer, and translate the drawings;

Step 2: Make a  of the product is generated for better understanding;

Step 3: Engineers make a design and produce documents to show the details: the heat treatment temperature, heat treatment time, casting temperature, casting time, keep the temperature time;

Step 4: Make product models. Our models include steel model, wood pattern models;

Step 5: Start to prepare and analyze the raw material;

Step 6:Products are poured using a bottom pour ladle;

Step 7: After cooling time, remove gating and risers, the goods start to heat treatment;

Step 8: Cone crusher liner Machining;

Step 9: Printing and package.