Process Equipment and Plant Design

261. The buckling tendency of compression members is always in the direction of the

1. Least radius of gyration
2. Axis of the load
3. Perpendicular to the axis of the load
4. None of these

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262. The centre to centre distance between two consecutive baffles in a shell and tube heat exchanger is called the baffle pitch or baffle spacing, which is more than 1/5th the I.D. of the shell. Which of the following is not a function of the baffles?

1. To increase the residence time of shell side fluid
2. To provide support to the tube bundle
3. To reduce the induced vibration in the tubes
4. To increase the tube side heat transfer co-efficient by inducing turbulence

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263. The circumferential (hoop) stress in a thin walled cylindrical vessel under internal pressure is

1. pd/2t
2. pd/4t
3. pd/t
4. pd/3t

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264. The clearance between two tubes in a shell and tube heat exchanger is known as 'ligament', whose minimum value is _________ the outside diameter of the tube, but in no case it should be less than 4.5 mm.

1. Equal to
2. Half
3. One fourth
4. Three fourth

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265. The design stress, which is more than the damaging stress, is the least unit stress that will render a member unfit for service before the end of its normal life. The design stress factor or factor of safety indicates the margin between design stress and the _________ stress.

1. Working
2. Damaging
3. Allowable
4. None of these

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266. The diameter of a propeller agitator used in agitation tank ranges from _________ percent of the tank diameter and its peripheral speed is normally 300 to 500 metres/minute.

1. 5 to 10
2. 15 to 30
3. 40 to 50
4. 55 to 75

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267. The difficulty of liquid distribution in packed towers is accentuated, when the ratio of tower diameter to packing diameter is

1. < 30
2. < 7
3. > 7 < 15
4. > 20 < 50

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268. The distance between the centres of a rivet hole to the nearest edge of the plate is called

1. Pitch
2. Margin
3. Back pitch
4. None of these

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269. The distance between the top of the slots and the liquid surface when the static liquid is just ready to flow over the overflow weir is called

1. Downcomer liquid seal
2. Static submergence
3. Skirt clearance
4. None of these

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270. The dust collection efficiency of a cyclone separator

1. Decreases with increase in gas flow rate
2. Is inversely proportional to the mass of the dust particle
3. Is directly proportional to the radius of the dust particle path
4. None of these

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