Hydraulic Machines MCQ with answer and solution

Concept

An air vessel is a closed chamber fitted on the suction and delivery pipes, close to the pump, to make the flow uniform.

Step-by-step solution

1. An air vessel is a closed cast iron chamber. It has compressed air at the top and liquid at the bottom. 2. It is connected to the suction pipe and the delivery pipe, very near the cylinder. 3. Its job is to give nearly uniform flow, cut friction loss, save power and stop separation. 4. Of the given options, only 'fitted in the delivery pipe' matches the standard arrangement. 5. So the answer is A.

Explanation

An air vessel stores and releases water to smooth out the varying flow of a reciprocating pump. It is fitted on the delivery pipe (and also on the suction pipe) close to the pump. Among the options, A is the correct choice.

Why the other options are wrong

B: 'Ahead of the pump' is vague. Air vessels are placed on the pipes near the cylinder, not ahead of the pump. C: Air vessels are commonly fitted, so 'not fitted' is wrong. D: The air vessel is part of the pipe system, not outside it.

Shortcut

Air vessel = on suction and delivery pipes, near the cylinder.

Common mistake

Thinking air vessels are used only on centrifugal pumps, or that they are fitted away from the pump.