Mechanical Operation Lab

Vibrating screens are those, which rapidly vibrated with small amplitude, are less likely to blind than gyrating screens. The vibrations may be generated mechanically or electrically. Mechanical vibrations are usually transmitted from high-speed eccentrics to the casing of the unit and from there to inclined screens. The setup consists of three different screen with fitted on a rigid M.S. frame, feed hopper, eccentric etc. Three screens of different sizes are fitted one above the other. The drives are given from an electric motor.

The universal mixing and kneading machine consists of two counter-rotating blades in a rectangular trough curved at bottom to form two longitudinal half cylinders and a saddle section. The blades are driven by gearing at either or both ends. The mixing action is a combination of bulk movement, smearing, stretching, folding, dividing and recombining as the material is pulled and squeezed against blades, saddle and sidewalls. The blades are pitched to achieve end-to-end circulation. Rotation is usually such that material is drawn down over the saddle. The blades are tangential and run at different speeds, with the advantages of faster mixing from constant change of relative position. The blade design most widely used is the sigma blade. The sigma blade mixer is capable of starting and operating with either liquids or solids or a combination of both. The sigma blade has good mixing action, readily discharges materials that do not stick to the blades, and is relatively easy to clean when sticky material are being processed. The drive is given through an electric motor coupled to a reduction gearbox. The whole assembly is fitted on rigid MS structure. The tilting mechanism is provided for discharge of product.

Pressure filters can apply a large pressure differential across the septum to give economically rapid filtration with viscous liquids or fine solids. The most common types of pressure filters are filter press. A filter press contains a set of plates designed to provide a series of chambers or compartments in which solids may collect. The plates are covered with a filter medium such as canvas cloth. Slurry is admitted to each compartment under pressure; liquor passes through the canvas cloth and out a discharge pipe, leaving a wet cake of solids behind. Plates and frames sit horizontally in a metal rack, with cloth covering the face of each plate, and are squeezed tightly together by a screw. Slurry enters at one end of the assembly of plates and frame. It passes through a channel running lengthwise through one corner of assembly. The set up consists of 7 plates and 6 frames. Frames are covered with filter cloth. Feed is fed by gear pump at the top and filtrate collected at the bottom from each plate by operating the cock. After removing Cake, washing and cleaning can be done by water provided by overhead tank. Inlet & outlet pressures are measured by pressure gauges. Rate of filtrate removals is measured by calibrated tank provided.

A Cyclone Separator is a vertical cylinder with the inlet stream introduced tangentially near the top, giving the suspension a spinning rotation in the cylinder. The centrifugal force acting on the particles tends to throw them radially to the sides of the cylinder as they spiral downward to a conical bottom where they are removed. A collector is fitted at the bottom & the induced draft blower is used to create the air stream. The classified air leaves the cyclone through a pipe extended down into the cyclone & passes through blower delivery side fitted with fine screen cloth bag to avoid dust expansion in the laboratory. The setup consists of I.D. blower connected to discharge side of Cyclone Separator. A flow meter with manometer is provided to measure the flow rate of air. Pressure drop in the Cyclone is measured by water manometer. Solids are collected in the collector fixed at the bottom. The set-up is complete with flow control & by-pass valve.

Gyratory type shaker is driven by FHP motor through a reduction gear suitable to carry up to 7 sieves of 15 cm or 20 cm diameter. When clamped the sieve table does not rotate but it is inclined from the vertical axis and the direction of inclination changes progressively in the clockwise direction. In addition to the gyratory motion of the Shaker, there is an upward and downward movement ensuring that each square inch of the sieve is utilized. The whole mechanism runs in an oil bath. Complete with adopter for 20-cm diameter sieves. Suitable for use from 220/230 volts 50 Hz.AC supply. Test Sieves will be supplied at an extra cost. A time switch from 0 to 60 minutes is provided.

The Lab setup is used to crush different sample and material. Two heavy Smooth faced chilled metal rolls turning on parallel horizontal axes are the working elements of the roll crusher. A hopper is provided at the top for feeding the material. Particles of feed caught between the rolls are broken in compression and drop out below. The rolls turn towards each other at the same speed. They have relatively narrow faces and are larger in diameter so that they can nip moderately large lumps. Loading bolts are provided for safety. The maximum size of the product is approximately equal to gap between the rolls & it can be adjusted by loading bolts.

Jaw Crusher is designed to speed up the crushing of aggregates, ores, minerals, coke, chemicals and others similar materials. It is compact and of rugged construction for general laboratory or small pilot plant operations. The set-up contains two Jaws of hard steel with one Jaw stationary and other moving. The movable jaw produces blows for every revolution reducing over sizing to a minimum. A combination of forward and downward strokes with a rocking action exert pressure on the coarser materials yet permits the finished materials to pass through the jaws. A hopper is provided at the top for feeding material. The smooth jaws ensure a uniform product and easy cleaning is possible. The opening of the Jaw is adjustable. The motor is coupled to the machine through Triple `V' belt drive

Ball Mills are horizontal rotating cylindrical steel chamber of half filled with steel balls. The size reduction is accomplished by the impact of balls as they fall back after being lifted by the baffles fitted in the rotating chamber. Ball Mill is fitted on a sturdy MS frame. Charging of balls and material is done by the means of opening provided in the chamber. The chamber is turning about the horizontal axis through a reduction gearbox drive through a ½ HP variable speed motor. Drive is provided to vary the RPM. A RPM indicator with proximity switch is provided in the set-up. A revolution counter is provided to find out the number of turns. Special arrangement is done to free the Ball Mill from reduction gearbox for charging and discharging the material.