Process Equipment and Plant Design

321. Thin spherical shells subjected to internal pressure, develop _________ stresses.

1. Radial
2. Circumferential
3. Both (A) & (B)
4. Neither (A) nor (B)

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322. To avoid the tearing off the plate of an edge, the margin (i.e., the minimum distance from the centre of the rivet hole to the nearest edge of the plate) should be equal to

1. 0.5 d
2. d
3. 1.5 d
4. 2.5 d

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323. To keep the power input constant for a stirred vessel operating under fully developed turbulent flow conditions (constant power number), if the impeller diameter is increased by 20%, the impeller speed should be decreased by a factor of

1. (1.2)^3/2
2. (1.2)^3/5
3. (1.2)^2/3
4. (1.2)^5/3

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324. Triangular pitch tube layout as compared to square pitch in a shell and tube heat exchanger

1. Permits the use of less tubes in a given shell diameter
2. Facilitates comparatively easier external cleaning because of large clearance
3. Permits the use of more tubes in a given shell diameter
4. Both (B) and (C)

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325. Tube height in a calandria type evaporator is normally less than _________ metres.

1. 1
2. 2
3. 3.5
4. 5.5

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326. Tube side heat transfer co-efficient for turbulent flow of liquid through tubes is proportional to

1. G^0.2
2. G^0.5
3. G^0.8
4. G^1.5

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327. Tube side pressure drop in a 1-2 heat exchanger (for turbulent flow of fluids through the tubes) is about _________ times, that in a 1-1 heat exchanger having the same size & number of tubes and operated at the same liquid flow rate.

1. 2
2. ½
3. 4
4. 8

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328. Tube wall thickness depends on the corrosiveness of the fluids and their operating pressure & temperature and is specified by Birmingham wire gauge (B.W.G)-a number which varies from 8 to 18 with the numbers 14 and 16 being more commonly used. Outside diameter of tubes varies from about 15 to 50 mm; however a tube of less than _________ mm outside diameter is generally not recommended for fouling fluids.

1. 16
2. 19
3. 28
4. 38

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329. Tubes are fixed to the tube sheet (a thick circular metallic plate) by the method of tube rolling and brazing (non-removable) or ferrule connection (removable). Thickness of the tube, sheet is normally _________ the outside diameter of the tube but in no case it should be less than 22 mm (7/8").

1. Half
2. Three fourth
3. Equal to
4. 1.5 times

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330. Typical static submergence for bubble cap plate column operating at atmospheric pressure may be around

1. 2.5"
2. 0.5"
3. 5"
4. 50% of the plate spacing

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