Engineering Questions with Answers - Multiple Choice Questions
Primary Production of Milk Engineering MCQs
1 - Question
Which of the following centrifugal pumps has higher specific speed than the others?
a) Axial flow
b) Radial flow
c) Mixed flow
d) All centrifugal pumps have same specific speed
View Answer
Explanation: An axial flow pump is a type of centrifugal pump that uses an impeller with vanes that direct the flow axially. Axial flow pumps create less pressure as compared to radial flow centrifugal pumps, but they can produce much higher flow rates.
2 - Question
Pump transfers the mechanical energy of a motor or of an engine into _________ of a fluid.
a) Pressure energy
b) Kinetic energy
c) Either pressure energy or kinetic energy
d) Pressure energy, kinetic energy or both
View Answer
Explanation: A pump is a machine used to convert mechanical energy (shaft movement) into hydraulic energy. Hydraulic energy could be in the form of pressure energy or kinetic energy or a combination of both. An electrical motor usually supplies the mechanical energy to the pump.
3 - Question
Which of the following is NOT a type of positive displacement pumps?
a) Reciprocating pump
b) Rotary displacement pump
c) Centrifugal pump
d) None of the mentioned
View Answer
Explanation: Centrifugal pump is not a positive displacement pump. Reciprocating pumps move liquid by means of a constant back-and-forth motion of a piston, plunger, or diaphragm within a fixed volume or cylinder. Reciprocating pumps can handle viscous and abrasive fluids. They are low-speed machines when compared with centrifugal and rotary.
4 - Question
Rotary displacement pumps are suitable for handling ________
a) Oils
b) Gritty liquids
c) Both oils as well as gritty liquids
d) Granules
View Answer
Explanation: Positive displacement rotary pumps rely on fine clearances between moving parts for their efficient operation. When used for lubricating oil and hydraulic systems, rotary displacement pumps benefit from the sealing effect and provision of lubrication between parts.
5 - Question
Which of the following is/are not example/s of rotary displacement pumps?
a) Gear pump
b) Vane pump
c) Rotary piston pump
d) Centrifugal pump
View Answer
Explanation: Rotary-type positive displacement: internal gear, screw, shuttle block, flexible vane or sliding vane, circumferential piston, and flexible impeller, helical twisted or liquid-ring pumps.
6 - Question
___________ pump is also called as velocity pump.
a) Reciprocating
b) Rotary displacement
c) Centrifugal
d) Screw
View Answer
Explanation: Centrifugal pump is commonly known as velocity pump. A centrifugal pump imparts velocity to a liquid. This velocity energy is then transformed largely into pressure energy as the liquid leaves the pump.
7 - Question
Discharge capacity of the reciprocating pump is __________ that of the centrifugal pump.
a) Higher than
b) Lower than
c) Same as
d) Unpredictabl
View Answer
Explanation: The capacity of a pump has two components, the pump discharge rate and the discharge pressure. The discharge rate is normally measured in gallons per minute (gpm) in English units or liters per second (lps) in metric units. Discharge capacity of the reciprocating pump is less that of the centrifugal pump.
8 - Question
Which pump is more suitable for an application where very high pressure is required to be developed at moderate discharge?
a) Reciprocating pump
b) Centrifugal pump
c) Turbine
d) None of the mentioned
View Answer
Explanation: Reciprocating pumps are generally designed to pump in low flow, high head applications. One of the most extreme of these applications is water jet cutting, where only a few gallons pass through the pump per minute, but exceed pressures of 10,000 PSI.
9 - Question
The process of filling the liquid into the suction pipe and pump casing up to the level of delivery valve is called as _________
a) Filling
b) Pumping
c) Priming
d) Leveling
View Answer
Explanation: Most pumps are not self-priming. In other words, the pump casing must be filled with liquid before the pump is started, or the pump will not be able to function. In case the pump casing gets filled with vapors or gases, the pump impeller becomes gas-bound and incapable of pumping.
10 - Question
The volute pumps and vortex volute pumps are __________ pumps with _________ shaft.
a) Multistage, horizontal
b) Multistage, vertical
c) Single stage, horizontal
d) Single stage, vertical
View Answer
Explanation: The volute pumps and vortex pumps are single stage pumps with horizontal shaft. They are both a type of centrifugal pumps.
11 - Question
Most widely used sanitary pumps in the dairy industry are?
a) Centrifugal pump
b) Liquid ring pump
c) Positive displacement pump
d) Suction pump
View Answer
Explanation: Typical dairy pumps are the centrifugal, liquid-ring and positive displacement pumps. The three types have different applications. The centrifugal pump is the type most widely used in dairies.
12 - Question
Main application of centrifugal pump is in which of the following?
a) Low viscosity products
b) Heavily aerated liquids
c) Gentle treatment with high viscosity
d) Water treatment
View Answer
Explanation: The centrifugal pump can be used for pumping of all liquids of relatively low viscosity which do not require particularly gentle treatment. It can also be used for liquids containing relatively large particles, provided of course that the particle size does not exceed the dimensions of the impeller channel.
13 - Question
Main application of liquid ring pump is in which of the following?
a) Low viscosity products
b) Heavily aerated liquids
c) Gentle treatment with high viscosity
d) Water treatment
View Answer
Explanation: Liquid-ring pumps for the dairy industry are used where the product contains large quantities of air or gas, and where centrifugal pumps therefore cannot be used. The clearances between impeller and casing are small, and this type of pump is therefore not suitable for handling abrasive products.
14 - Question
Main application of positive displacement pump is in which of the following?
a) Low viscosity products
b) Heavily aerated liquids
c) Gentle treatment with high viscosity
d) Water treatment
View Answer
Explanation: This type of pump has 100% volumetric efficiency (no slip) when the viscosity exceeds approximately 300 cP. Because of the sanitary design and the gentle treatment of the product, this type of pump is widely used for pumping cream with a high fat content, cultured milk products, curd/whey mixtures, etc.
15 - Question
Which of the following pump suitable for handling AMF in the dairy industry?
a) Centrifugal pump
b) Liquid ring pump
c) Diaphragm pump
d) Peristaltic pumps
View Answer
Explanation: In Peristaltic pumps, during rotation, the medium (liquid or gas) inside the hose is transported to the lower outlet connection. This creates a vacuum on the suction side, and the product is drawn into the pump. The pump is self-priming and is therefore suitable for emptying barrels with juice concentrates and anhydrous milk fat (AMF).
16 - Question
What is the aim of pipes system in the dairy industry?
a) Facilitate product flow
b) Pasteurization
c) Fouling
d) Storage
View Answer
Explanation: The product flows between the components of the plant in the pipe system. A dairy also has conduit systems for other media such as water, steam, cleaning solutions, coolant and compressed air.
17 - Question
Which material is used for pipes which are in contact with milk or product?
a) Stainless steel
b) Copper
c) Ceramic
d) Plastic
View Answer
Explanation: All components in contact with the product are made of stainless steel. Stainless steel is easy to clean and non corrosive.
18 - Question
Which material is used for pipes which conduct water and air?
a) Stainless steel
b) Copper
c) Ceramic
d) Plastic
View Answer
Explanation: Plastic is used for water and air lines. Plastic also provides transparency.
19 - Question
Which material is used for pipes which conduct waste?
a) Stainless steel
b) Copper
c) Ceramic
d) Plastic
View Answer
Explanation: Various materials are used in the other systems, e.g. cast iron, steel, copper and aluminum. Plastic is used for water and air lines, and ceramic for drainage and sewage pipes.
20 - Question
Which grade of stainless steel is known as acid proof steel?
a) AISI 304
b) AISI 316
c) SIS 2333
d) SIS 2359
View Answer
Explanation: For hygienic reasons, all product-wetted parts of dairy equipment are made of stainless steel. Two main grades are used, AISI 304 and AISI 316. The latter grade is often called acid proof steel.
21 - Question
Which of the following are installed in order to collect product samples hygienically for quality analysis?
a) Bends
b) Reducers
c) Sampling device
d) Tees
View Answer
Explanation: Sampling devices need to be installed at strategic points in the plant to collect product samples for analysis. For quality control, such as determining the fat content of milk and the pH value of cultured products, the samples can be collected from a sampling cock.
22 - Question
Which among the following is not a permanent wielding connection?
a) Bends
b) Reducers
c) Sampling device
d) Tees
View Answer
Explanation: Some examples of fittings for permanent welding are Tees, reducers and bends. This union allows disconnection without disturbing other pipe work. This type of joint is hence used to connect process equipment, instruments, etc. that need to be removed for cleaning, repair or replacement.
23 - Question
What are the reasons causing pressure drop in hydraulic systems? i. Long length of pipe ii. Friction iii. Type of fluid iv. Losses in valves and bends
a) i and iv
b) Only i
c) ii and iii
d) i, ii, iii and iv
View Answer
Explanation: Pressure drop is the difference in the pressure of liquid entering the hydraulic system and pressure of liquid leaving the system. Long length of pipe, friction, fluid type and losses in valves and bends are all reasons behind pressure drop in hydraulic system.
24 - Question
Calculate area of a pipe if, flow rate is 20 l/min and flow velocity is 5 cm/s.
a) 66.66 cm2
b) 60 cm2
c) 62 cm2
d) 64 cm2
View Answer
Explanation: Flow rate = 20 litre/min = 200000 cm3/60s = 333.33 cm3/s Flow Rate = Velocity x Area 333.33cm3/s = 5cm/s x Area Area = 333.33cm3/s / 5 cm/s = 66.66 cm2.
25 - Question
Which formula is used to calculate head loss in valves?
a) K2 (v/2 g)
b) K (v/2 g)
c) K (v2/2 g)
d) K3 (v2/2 g)
View Answer
Explanation: K (v2/2 g) calculates head loss for Newtonian fluid. When fluid flows inside a pipeline, friction occurs between the moving fluid and the stationary pipe wall. The friction converts some of the fluid’s hydraulic energy into thermal energy. The thermal energy cannot be converted back to hydraulic energy, so the fluid experiences a drop in pressure. This conversion and loss of energy is known as head loss.
26 - Question
Which among the following is shut-off and change over valve?
a) Seat valve
b) Butterfly valve
c) Seat valve and butterfly valve
d) Bend
View Answer
Explanation: There are many places in a piping system where it must be possible to stop the flow or divert it to another line. These functions are performed by valves. Seat valves, manually or pneumatically controlled, or butterfly valves, are used for this purpose.
27 - Question
To prevent the product flow in the wrong direction which of the following valve is used?
a) Seat valve
b) Butterfly valve
c) Seat valve and butterfly valve
d) Check valve
View Answer
Explanation: A check valve is fitted when it is necessary to prevent the product from flowing in the wrong direction. The valve is kept open by the liquid flow in the correct direction. If the flow stops, the valve plug is forced against its seat by the spring. The valve then closes against reversal of the flow.
28 - Question
Which of the following valves is used to maintain pressure in the system?
a) Pressure relief valve
b) Check valve
c) Manual control valve with variable flow plug
d) Pneumatic control valve with variable-flow plug
View Answer
Explanation: A pressure relief valve maintains the pressure in the system. If the pressure is low, the spring holds the plug against the seat. When the pressure has reached a certain value, the force on the plug overcomes the spring force and the valve opens.
29 - Question
The pipes will expand considerably when the product temperatures are high and during cleaning.
a) True
b) False
View Answer
Explanation: Pipes must be firmly supported. On the other hand the pipes should not be so restrained that movement is prevented. The pipes will expand considerably when the product temperatures are high and during cleaning. The resulting increase in length and tensional forces in bends and equipment must be absorbed.
30 - Question
Valves with constant outlet pressure are used after which of the following machines?
a) Separator
b) Pasteurizer
c) Homogenizer
d) Filling machine
View Answer
Explanation: Valves for constant inlet pressure are often used after separators and pasteurizers. Those for constant outlet pressure are used before filling machines.