S7 Flashcards
To get ultrafine particles, the equipment used is a
fluid energy mill
Vacuum filter is most suitable for the
none of these.
The porosity of a compressible cake is
minimum at the filter medium.
Which of the following conveyors cannot be recommended for transportation of abrasive materials?
Flight conveyor
Separation of materials into products based on the difference of their sizes is called
sizing
For classification of potable (drinking) water, we use a __________ filter.
gravity sand
Hot, lumpy & abrasive materials are best transported by using a/an __________ conveyor.
apron
In case of grinding in a ball mill
all (a), (b) and (c).
The capacity of a classifier in ‘tons of solid/hr’ is given by (where, A = cross-sectional area, m2V = rising velocity of fluid, m/sec.S = percentage of solids in the suspension by volume.ρ = density of solids, kg/m3)
3.6 AVS.ρ
Kick’s law relates to
energy consumption
__________ mill is normally used for grinding of talc.
Ring-roll
Colloidal mills are used for __________ grinding.
ultrafine
The maximum slope of a belt conveyor can be
30°
The filter medium resistance is controlled by
both pressure drop and flow rate
The unit of filter medium resistance is
cm^-1
During size reduction by a jaw crusher, the energy consumed decreases with the
increasing size of feed at constant reduction ratio.
Which of the following can be most effectively used for clarification of lube oil and printing ink?
Sharpies supercentrifuge
Ultracentrifuges running at speeds upto 100000 rpm is normally used for the
separation of isotopes based on their density or molecular weights difference.
Sizing of very fine particles of the order of 5 to 10 microns is done by elutriation, which is a __________ operation.
classification
The basic filtration equation is given asdt/dV = µ/A ∆P (a . CV / A + Rm) where,V is volume of the filtrate ;Ais the filtration area, a is specific cake resistance, μ is viscosity of the filtrate, andC is the concentration of the solids in the feed slurry.
In a 20 minutes constant rate filtration, 5 m3of filtrate was obtained. If this is followed by a constant pressure filtration, how much more time in minutes, it will take for another 5 m3of filtrate to be produced? Neglect filter medium resistance,Rm; assume incompressible cake.
20
Size reduction of fibrous materials like wood, asbestos, mica etc. is done by a disintegrator exemplified by the
cage mill
The material is crushed in a gyratory crusher by the action of
compression
The equivalent diameter of channel of a constant non-circular cross-section of 3 cm by 6 cm will be __________ cms.
2
Which of the following may prove unsuitable for filtering volatile liquids?
Vacuum filter
__________ mean diameter of particles is given by∑ (xi / Dpi)
volume
Mass flow of granular solid (M) through a circular opening of dia,Dfollows
M∝D^3
Sauter mean diameter is the same as the __________ mean diameter.
volume-surface
Cake resistance is
none of these.
In paint industries, blending of light paste is done by using a
charge can mixer
A sand mixture was screened through a standard 10-mesh screen. The mass fraction of the oversize material in feed, overflow and underflow were found to be 0.38, 0.79 and 0.22 respectively. The screen effectiveness based on the oversize is
0.50
__________ is used for producing a thick suspension from a thin slurry.
Pressure filter thickener
Wet seiving is employed, when the product contains __________ materials.
large quantity of very fine
Energy requirement (per unit mass of material crushed/ground) is highest for
fluid energy mill
The energy consumed by a ball mill depends on
all (a), (b) and (c).
Energy consumption in a crusher decreases with increase in the
all (a), (b) & (c).
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).
Peclet
The term ‘angle of nip’ is concerned with the operation of the __________ crushers.
roll
Cartridge filters are termed as ‘edge’ filters, because of the fact that the
bulk of the solids are removed at the periphery of the disks.
Vibrating screens have capacity in the range of __________ tons/ft^2.mm mesh size.
0.2 to 0.8
Cumulative analysis for determining surface is more precise than differential analysis, because of the
assumption that all particles in a single fraction are equal in size, is not needed.
To remove very small amount of tiny solid impurities from liquid, we use a
coagulant
Screw conveyors are
suitable for sticky materials.
__________ mills fall in the category of tumbling mills,
all (a), (b) & (c)
Capacity of flight conveyor in tons/hr is given by (where,W&D= width and depth of flight respectively in metreV= speed of the conveyor, metre/second ρ = bulk density of material, kg/m3)
3.6W.D.V.ρ
Which of the following is not a cutting machine?
Tube mills
Weber number is significant and is concerned with the
dispersion of liquid in liquid.
Power consumption during turbulent flow in agitation tank is proportional to the __________ of the liquid.
density
