# Mechanical Operations Questions and Answers – Floatation

This set of Mechanical Operations Multiple Choice Questions & Answers (MCQs) focuses on “Floatation”.

1. After the layer of precoat is exhausted, filtration is _____
a) Lesser
b) Started
c) Stopped
d) Greater

Explanation: After the layer of precoat is exhausted, filtration is stopped and a new thick layer of precoat is deposited and filtration is continued.

2. ______ consists of introducing water through the strainers.
a) Front washing
b) Backwashing
c) Stripping
d) Distillation

Explanation: Backwashing consists of introducing water through strainers so that it may flow up through the sand bed and out through the connection.

3. What is the capacity of a sand filter?
a) 2 to 4 GPM
b) 1 to 3 GPM
c) 8 to 10 GPM
d) 50 to 60 GPM

Explanation: The capacity of an average sand filter is from 2 to 4 GPM per square feet of filtering area, GPM represents gallon per minute.

4. ______ filters are operated under super atmospheric pressure.
a) Drag
b) Cyclone
c) Gravity
d) Pressure

Explanation: Pressure filters are operated under super atmospheric pressure at filtering surface or greater pressure at the downstream side.

5. At what pressure, cake filters are operated?
a) < 50 psi
b) < 100 psi
c) >25 psi
d) <25 psi

Explanation: Cake pressure filters are operated at a pressure of less than 25 psi, but the pressure may go up to 75 psi for high end special operations.
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6. In a plate frame press, the size of a plate is?
a) 100 to 200 inch
b) 50 to 60 inch
c) 10 to 12 inch
d) 12 to 36 inch

Explanation: The plates are usually made up of cast irons from 12 to 36 inch across, approx. ½ inch thick and with a raised edge from ½ to 2 inches.

7. When cake is finally accumulated, closing screw is _____
a) Started
b) Packed
c) Released
d) Tightened

Explanation: When sufficient cake has accumulated to fill the chambers, the closing screw is released, the follower is drawn back along the supporting rails.

8. The chamber press is adapted for washing the cake.
a) True
b) False

Explanation: It is hard to get a clean discharge of cake and most important, the wear on the cloth is severe, so the chamber press is not at all adapted for the same.

9. Which of the following represents the setup of two single, three triple and four dual plates?
a) 1-1-1-3-3-3-3-2-2
b) 1-2-1-1-2-1-3-3
c) 1-2-1-2-3-3-3-2-2
d) 3-3-3-1-2-2-3-1

Explanation: The setup so assembles should consists a chain of 2- 1’s, 3-3’s and 2-2’s i.e. 1-2-1-2-3-3-3-2-2 which is the perfect setup.

10. When filtration reaches the practical limit, connection is _____
a) Opened
b) Closed
c) Expanded
d) Contracted

Explanation: Filtration is carried out in the non-washing plate and frame press, when it is at final limit and good cake is formed, the feed connection is closed.

Sanfoundry Global Education & Learning Series – Mechanical Operations.

To practice all areas of Mechanical Operations, here is complete set of 1000+ Multiple Choice Questions and Answers.

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