Mechanical Operations Quiz 4

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

In case of a ball mill ?

Jigging is a technique by which different particles can be______?

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

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

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

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

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

In a roll crusher, both the rolls__________?

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

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?

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 constant pressure filtration ?

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

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

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

In case of grinding in a ball mill___________?

In bag filters, filter fabrics are never made of___________?

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

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

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

Mixer used for rubber compounding is___________?

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) ?

Limestone is normally crushed in a _______?

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?

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

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?

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

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

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

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

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?

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

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

Length/diameter ratio of a ball mill is ___________ ?

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

Helical screw agitator is used for_________?

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_________?

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__________?

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?

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) ?

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

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

In case of a hammer crusher ?

increasing the capacity of a screen ________ the screen effectiveness?

Mesh indicates the number of holes per__________?

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

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_________?