Mechanical Operations Quiz 4

In case of a revolving mill, wet grinding compared to dry grinding___________?

In a ball mill, the volume occupied by the balls (when the mill is stopped) is about ________ percent of the volume of the mill?

In a size reduction crushing operation, the feed size is 10 to 50 mm, while the product size is 2 to 10 mm. This is a case of ________ crushing?

Height of liquid in agitation tank is normally maintained equal to the tank diameter. However, if the tank is too tall and a large liquid hold up is desired, then two or more impellers mounted on the same shaft may be used. The clearance between the tank bottom and the bottom most impeller should be about (where, D = impeller diameter) ?

Highly viscous liquids & pastes are agitated by_________?

Hot, lumpy & abrasive materials are best transported by using a/an ___________ conveyor ?

In constant pressure filtration ?

In case of a hammer crusher ?

Mass flow of granular solid (M) through a circular opening of dia, D follows_______?

In a mixer, the quantity, (v. L/D) is termed as __________ number (where, v = longitudinal velocity of material, L = length of the mixer, D = diffusivity in axial mixing) ?

Horsepower required for a roll crusher is directly proportional to its___________?

If a force greater than that of gravity is used to separate solids & fluids of different densities, the process is termed as the ___________?

Introduction of slurry in a plate and frame filter press is done through a plate in each frame. The plate of this filter has a ________ surface?

Half the angle of nip, (?), for a roll crusher is given by (where, dr, dp and df are diameters of crushing rolls, feed particles and rolls gap respectively) ?

Handling of ashes and similar materials can be done best by a _______ conveyor?

In closed circuit grinding as compared to open circuit grinding, the__________?

Maximum size reduction in a ball mill is done by the, _______ action?

In a size reduction crushing operation, feed size is 100 to 300 mm. while the product size is 10 to 50 mm. This is a case of the ______ crushing?

If radius of a batch basket centrifuge is halved & the r.p.m. is doubled, then the__________?

Kick?s law assumes that the energy required for size reduction is proportional to the logarithm of the ratio between the initial and the final diameters. The unit of Kick?s constant is__________?

Helical screw agitator is used for_________?

In screen analysis, the notation +5 mm/-10 mm means particles passing through ______?

In froth floatation, chemical agent added to cause air adherence is called_____?

Higher is the mesh number, smaller will be the aperture size of the screen. It means that the aperture size of a 200 mesh screen will be smaller than that of 20 mesh screen. This is valid for___________?

In coal washeries, three products namely the valuable product (i.e. clean/washed coal), discarded product (i.e. mineral matter) and an additional concentrated product called ______ is produced?

Jigging is a technique by which different particles can be______?

Mixer used for rubber compounding is___________?

Mesh indicates the number of holes per__________?

In filtration, the use of ?filter aid? helps in___________?

In case of a ball mill ?

Length/diameter ratio of a ball mill is ___________ ?

In washing type plate and frame filter press, the ratio of washing rate to the final filtrate rate is___________?

increasing the capacity of a screen ________ the screen effectiveness?

In case of a hammer crusher, the final product size depends on the______?

In a roll crusher, both the rolls__________?

In a grinding operation, the limiting particle size is the size of the ________ particle in the sample?

In case of grinding in a ball mill___________?

In the cyclone separator used for separation of dust from dust laden gas, the gas ?

In a roll crusher, the specific power consumption and the production rate is affected by the__________?

Maximum size reduction in a fluid energy mill is achieved by_____?

Limestone is normally crushed in a _______?

In case of a plate and frame filter press, filtrate flow through the cake follows ________ flow?

Laminar flow region is said to exist during agitation of a liquid in an agitator, when the value of Reynolds number is_________?

In continuous filtration (at a constant pressure drop), filtrate flow rate varies inversely as the___________?

Mechanical conveyors which push the material along an endless trough or tube are called scrappers. Which of the following conveying equipments comes under the category of ?scrappers? ?

In classification, particles are said to be equal settling, if they have the same terminal velocities in the________?

If dp is the equivalent diameter of a non-spherical particle, Vp its volume and sp its surface area, then its sphericity is ?s is defined by_________?

In a size reduction crushing operation, feed size is 300 to 1500 mm while the product size is 100 to 300 mm. This is a case of the _________ crushing?

In bag filters, filter fabrics are never made of___________?

Metallic wire mesh is used as a filtering medium for the separation of dust from dust laden gas in case of a/an_________?