Chemical Engineering : CRUSHER


Crusher: It is usually  used to break large piece  of solid materials into small lump.

Different types of crusher are used to reduced solid into different forms.

Course or Primary crusher reduce the solid upto 150-250 mm/ 6-10 inch lump

Secondary crusher reduce the solid upto 40 mesh.


*Jaw crusher is a type of crusher which produce coarse particle

* Feed size of the jaw crusher is 1500mm-40mm and the product size is from 50mm-5mm.

* Compressive strength of jaw crushers is 320 mega pascal.

* Rpm for jaw crusher is between 200-400.

* Jaw crusher are heavy duty machines and hence need to be robustly constructed.

* The outer frame is generally made of cast iron or steel.

* The jaws themselves are usually constructed from cast steel.

* They are fitted with replaceable liners which are made of manganese steel.


* A jaw crusher uses compressive force for breaking of particle.

* A jaw crusher reduces large size rocks or ore by placing the rock into compression. A fixed jaw mounted in a "V" alignment is the stationary breaking surface, while the movable jaw exerts force on the rock by forcing it against the stationary plate.

* The space at the bottom of the "V" aligned jaw plates is the crusher product size gap, or the size of the crushed product from the jaw crusher. The rock remains in the jaws until it is small enough to pass through the gap at the bottom of the jaws.


*Angle between two jaws is between 20-30 degree.

*Larger lumps caught between upper part of the jaw and broken into small piece by impact force.

*Small pieces come to narrower space at the bottom where compressive force do a sufficient size reduction and product obtained.

* Simple construction makes for easy maintenance.

* Stable performance

* High crushing ration

*Low operational cost

*High capacity

*Adjustable discharge port.


*Crushers are used-

1. Heavy duty mining
2. Cement industry
3. Fertilizers industry
4. Plaster of paris plant
5. Animal (cattle) feed plants.
6. Herbal plants
7. Cement plants
8. Ceramic plants
9. Coconut shell plant
10. Salt plant
11. Mines and Minerals
12. Agro based industries
13. Others where size reduction required.


* Gyratory crusher looked like a jaw crusher with circular jaws between which material is being crushed some point all the time.

* Rpm is 125-425 gyration per minute.

* Give a continues discharge because some part of the crushing head working all the time.

* Produces up to 4500 ton per hour of material being crushed.

* A gyratory crusher is similar in basic concept to a jaw crusher, consisting of a concave surface and a conical head, both surfaces are typically lined with manganese steel surfaces.

* The inner cone has a slight circular movement, but does not rotate, the movement is generated by an eccentric arrangement.

* As with the jaw crusher, material travels downward between the two surfaces being progressively crushed until is small enough to fall out through the gap between the two surfaces.

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