SUBJECT:-mechanical operation(2150502) SUBMITTED TO: - PROF.VINAY B. PATEL SUBJECT:-mechanical operation(2150502) TOPIC: - ROLL CRUSHER GROUP MEMBER:- NAME ENROLLMENT NO. RAJAPARA SAGAR 140113105007 SHARMA SHIVAM 140113105008 BHATT PURV 140113105009 DESHMUKH ASHISH 140113105010 DEPARTMENT OF CHEMICAL ENGINEERING G.H. PATEL COLLEGE OF ENGINEERING & TECHNOLOGY VV NAGAR.

CRUSHERS Crushers are the machine which is used to reduce the size of the rock so that all fragment are finer than the definite maximum size.

TYPES OF CRUSHERS Crushers are classified according to the stage of crushing which they accomplish, such as: Primary Secondary Tertiary A primary crusher receives the stone directly from a quarry after blasting, and produces the first reduction in size. The output of the primary crusher is fed to a secondary crusher, which further reduces the stone size. Some of the stone may pass through four or more crushers before it is reduced to the desired size.   The degree of breakage is spread over several stages as a means of closely controlling product size and limiting waste material.

Selection of crushing equipment The information needed should include, but will not necessarily be limited to, the following items: The kind of stone to be crushed. The maximum individual size of the feed stones and perhaps the size ranges of the feed to the plant. The method of feeding the crushers. The required capacity of the plant. The percent of material failing within specified size ranges.

SINGLE ROLL CRUSHER

FIELDS OF APPLICATION Single Roll Crushers are used for size reduction of products ranging from soft to medium-hard. FEED MATERIALS   Coal, coke, salt, slag, marl, chalk, chemical and Similar products.

MODE OF OPERATION The Single Roll Crusher carries out size reduction in a wedge- shaped crushing area by pressure and Shearing stress. The crushing body is composed of a rotating roll and an adjustable and spring-mounted crushing plate located on the opposite side. The distance between the bases of the crushing plate and the tips of the roll crusher’s teeth determines the adjustable gap width, which can be varied depending on the desired product size. Any wear and tear which may occur can be adjusted via the crushing plate. Depending on the feed material and the desired product size, the Roll Crusher is equipped with either teeth or ledges. The crushing plate is equipped with a replaceable comb plate.

SPECIAL FEATURES The crushing roll is firmly fixed onto the base frame of the machine. The crushing rings, shells or ledges, made of a special casting, are mounted up or bolted on the roller body of welded construction. The crusher shaft, made of high-grade steel, is arranged in amply-dimensioned spherical roller bearings. The bearing housings are equipped with lubricated labyrinths to avoid dust and dirt penetration. To adjust the gap width, the crushing plate is set by using threaded spindles. The spring elements provide initial tension for the crushing force and serve simultaneously as overload protection. The machine can be powered either hydraulically, by belt drive or a slip-on gear motor.

ADVANTAGES – high and constant capacity – high availability – long lifetime – easy replacement of wear and spare parts – wide range of application – high reduction ratio – with a minimum of fines

SCOPE OF APPLICATION – feed size: up to approx. 800 mm – product size: 15–150 mm depending on the feed material and its size – capacity: up to 1000 t/h – reduction ratio: up to 1 : 6 – required power: up to 200 kW

Introduction of roll crusher: In the mining industry, roll crushers are used to crush mines of medium or low hardness, rocks that have low or medium rigidity during mine selection, for cement, chemicals, and industrial production of building materials, among others. However, their use in the mining industry has greatly declined due to their inability to produce large amounts of output. In mining applications, the roll crusher does not match up to cone crushers, when considering the volume of production and maintenance costs. However, roll crushers have the advantage of producing a close distribution of the product size. In cases where the ore is not very abrasive, the maintenance costs are significantly reduced.

Theoretically speaking, the maximum reduction ratio of roll crushers is 4:1. For example, the smallest size that can be recognized by a particle of 2inches is 1/2 an inch. Using this machine, a material is crushed and reduced to a minimum particle size of 10Mesh (2mm). The materials are crushed by compression between two rolls rotating about a shaft. The size between the two rolls used for compression can be suitably adjusted according to the desired size of the end- product. It is important to note that the largest particle size of the materials inserted should not be more than four times the dimension of the gap.

Smooth Roll Crusher OR Double Roll Crusher Crusher Working principle of roll crusher(COMPRESSION): Smooth Roll Crusher OR Double Roll Crusher Crusher

MAJOR ADVANTAGES – high and constant capacity – low susceptibility to breakdowns – long lifetime – easy replacement of wear and spare parts – wide range of application – with a minimum of fine grains – gentle crushing

Applicable material of roll crusher: 1) Clay 2) Shale clay 3) Coal gangue 4) River silt THE SCOPE OF APPLICATION – Capacity: up to 2500 m3/h – Feeding size: up to approx. 1500 mm – Final grain size: 15 - 300 mm depending on the feed material and its size – Reduction ratio: up to 1 : 5 – Required power: up to 2 x 250 kW  

Feed materials Raw materials, secondary materials and by-products such as coke, sinter, coal, soft to medium-hard rock, ore, chalk, broken glass and similar products.Hour output: 150m3/h CAPACITY The capacity of the rolls depends upon their speed, the width of their faces ,their diameter, and their set. The theoretical capacity in tons per hours is C= 0.0034N*D*W*s*G Where N= no of revolutions per min D= diameter of the rolls W=width of face s= The set G=specific gravity of rock crushed All in inches. Actual capacity varies from 10-30% of the theoretical

Toothed Roll Crusher Structure of double teeth roller crusher: This type of machine is mainly composed of frame, housing, roll axle, spring, transmission section. It is driven by two motors and two belt wheels. The two rolls are driven by a motor v-belts and gears and rotate in opposite direction for crushing material. The clearance between two rolls is adjustable at a given range for proper control of discharge size.

Toothed Roll Crusher

Features and benefits of toothed roller crusher: Good performance to the material with the moisture not exceeding 15% Even discharging size without blocking up Full-sealed design and no dust pollution which meet environmental protection requirements and easy to collect samples Removable shell which is convenient for daily maintenance and inspection of the machine. Total electro-static coating surface which makes good appearance and easy to clean All moving parts have the safeguards which meets the requirements of work safety.

Application of double roller crusher: Double roll crusher series is designed to be used in the industrial branches of ore dressing, chemical engineering, cement, building material, steel industries and so on for medium and fine reduction of various ores and rocks with the hardness below medium level.

Working principle of double roll crusher: 1).The particles are drawn into the gap between the rolls by their rotating motion and a friction angle formed between the rolls and the particle, called the nip angle. 2).The two rolls force the particle between their rotating surface into the ever smaller gap area, and it fractures from the compressive forces presented by the rotating rolls. 3).Some major advantages of roll crushers are they give a very fine product size distribution and they produce very little dust or fines. 4).Coal plants will use roll crushers, either single roll or double roll, as primary crushers, reducing the ROM coal. Usually, these crushers will have teeth or raised forms on the face of the roll. 

ANGLE OF NIP Definition:- The largest angle that will just grip a lump between the jaws, rolls, or mantle and ring of a crusher. Also known as angle of nip In mechanical operation In a rock-crushing machine, the maximum angle subtended by its approaching jaws or roll surfaces at which a specified piece of ore can be gripped.

ANGLE OF NIP EQUATION where α = angle of nip r = radius of roll R = radius of feed particle d = roll diameter

ANGLE OF NIP