Food Processing Unit Operations Multiple Choice Questions on “Filtration Equipments”.
1. What is the advantage of vacuum filtration?
a) Efficiency
b) Faster than other filtration equipment
c) Cost effective
d) Low power cost
Answer: b
Clarification: Vacuum filtration is used to collect a desired solid, normally in recrystallization for the collection of crystals. These are faster than gravity filtration, because the solvent and air is forced through the filter paper by the using reduced pressure.
2. Identify the filtration equipment?
a) Centrifugal filtration
b) Rotary filtration
c) Plate and frame filter
d) Vacuum filter
Answer: a
Clarification: Centrifugation controls the influence of the centrifugal force for the separation. Centrifugation filtration is a process that depends on rotation to separate high density substances from low density substances.
3. Why is cotton wool used in filtration?
a) Remove fine particles
b) Moderately coarsely particles
c) Big particles
d) Uniform particles
Answer: b
Clarification: Cotton wool is used for filtering of moderately coarse particles. The disadvantage is presence of fine cotton hair in the filtrate. This is avoided by wetting the cotton wool plug with liquid before using it.
4. What is membrane filters made up of?
a) Cellulose acetate
b) Resins
c) Positively charge ions
d) Negatively charge ions
Answer: a
Clarification: The membrane filters are made of cellulose acetate and other cellulose derivatives, nylon and polyvinyl chloride. These are primarily used to remove microorganism and very fine particles from solution.
5. What is the disadvantage of the filter press?
a) The filtering media can be used repeatedly
b) Operation and maintenance is simple
c) It requires less space
d) It is used where the proportion of solid in the liquid to be filtered is about 5% or less
Answer: d
Clarification: The advantages of filter press are filtering media can be used repeatedly. Operation and maintenance is simple. It requires less space. It provides a large surface area for filtration. Efficient washing of cake is possible.
6. Is sintered filters are made up of borosilicate glass ?
a) True
b) False
Answer: a
Clarification: Sintered filters are made of borosilicate glass. Borosilicate glass is finely Powdered sieved and desired particle size are separated. It is then packed into a disc mould and heated to a temperature where adhesion takes place between the particles. Finally the disc is then fused to a funnel of suitable shape and size.
7. Where is Meta filters used?
a) Water treatment
b) Metal recovery
c) Clarification of syrups
d) Oil recovery
Answer: c
Clarification: The Meta filters have significant strength and therefore it can withstand the high pressure. The corrosive liquids can be filtered without any problem. It is a cost-effective filter. Cake is removed effectively without any difficulty.
8. What is hot filtration?
a) Prevent virus during filtration
b) Prevent bacteria during filtration
c) Minimize crystal formation during filtration
d) Prevent yeast during filtration
Answer: c
Clarification: In hot filtration, the solution, filter and funnel are heated to minimize the crystal formation during filtration. Stemless funnels are useful so that there is less surface area for crystal growth.
9. What is cold filtration?
a) To quickly cool a solution
b) Prevent bacteria during filtration
c) Minimize crystal formation during filtration
d) Prevent yeast during filtration