This set of Metal Casting Multiple Choice Questions & Answers (MCQs) focuses on “Dust Control and Dust Extraction in Foundry”.
1. What does LEV stand for?
a) Local Exhaust Ventilation
b) Limited Entry Ventilation
c) Local Entry Ventilation
d) Limited Exhaust ventilation
View Answer
Explanation: The LEV stands for Local Exhaust Ventilation system. This system has a ventilation place in a downward direction with a turn table to help manipulate the castings.
2. Which of the following would not be counted among foundry dust?
a) Bentonite
b) Silica
c) Iron
d) Sea coal
View Answer
Explanation: Among the following, bentonite, silica and sea coal are the materials from which a considerable amount of dust is found to remain in the foundries. Iron is not a part of it.
3. What will happen if continuously fine sands are removed from the molding mixture?
a) Brittleness
b) Poor finish
c) Less elasticity
d) More ductility
View Answer
Explanation: For controlling the sand, if the fine sand which is added in the molding sand is removed continuously, it may cause the casting to be formed with a poorer finish than desired.
4. Which disease is caused by the inhalation of silica sand?
a) Silver syndrome
b) Silicosis
c) Sillence syndrome
d) Sinus venosus
View Answer
Explanation: Silicosis is caused by the inhalation of silica sand, which in crystalline form. The inhalation of this sand causes inflammation in the upper part of the lungs. The characteristics are shortness of breath and fever.
5. What is the average velocity at the slit in Owan’s Jet counter apparatus?
a) 100 m/s
b) 150 m/s
c) 250 m/s
d) 360 m/s
View Answer
Explanation: The Owan’s Jet Counter works on very high velocity using a hand pump. The velocity of operation, of this apparatus is between 200 m/s to 300 m/s, which makes the average velocity of operation to be 250m/s.
6. What should be the width of the slit used in Owan’s apparatus?
a) 0.1 mm
b) 0.2mm
c) 0.3 mm
d) 0.4 mm
View Answer
Explanation: In the Owan’s counter jet apparatus, the length of the slit should be only 10 mm. But, the width of the slit is very small, being only 0.1 mm.
7. What is the amount of clearance allowed between the slits and the collecting plate in Owan’s appartaus?
a) 0.5 mm
b) 1 mm
c) 2 mm
d) 3 mm
View Answer
Explanation: In Owan’s apparatus, the amount of clearance that is allowed, in between the slits and the collecting plates is only 1 mm, the width for dust depository is only 70 micro meter.
8. Which of the following cannot be a way of spreading dust?
a) Enclosing the mixer
b) Screening the sand
c) Moistening the sand
d) Treating the cast chemically
View Answer
Explanation: For the prevention of spreading the dust, moistening and screening the sand can be options. By enclosing the mixer too sand spreading can be avoided. But by treating the cast chemically, its physical, chemical, as well as mechanical properties may change.
9. In pneumatic chisel, ventilation is applied through a duct over the operator’s hand.
a) True
b) False
View Answer
Explanation: In pneumatic chisel, ventilation is applied through three places in the apparatus. A duct over the operator’s hand, a duct connected on the chisel side and a hollow chisel present.
10. In pneumatic chisel, what is the dust velocity normally?
a) 270 meters/min
b) 330 meters/min
c) 370 meters/min
d) 430 meters/min
View Answer
Explanation: In pneumatic chisel, there is a vacuum created of up to 250 to 375 Hg. This enables the dust velocity to be around 370 meters/minute.
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