Reciprocating Pump Components — Definition of an Air Vessel Consider the statement: “The air vessel in a reciprocating pump is a cast iron closed chamber having an opening at its base (connected to the pipeline).” Choose the correct response.

Introduction:
Air vessels are classic accessories used with reciprocating pumps to smoothen discharge, reduce acceleration head, minimize power fluctuations, and prevent separation. Understanding their construction and connection helps in correct placement and operation.

Given Data / Assumptions:

• Reciprocating pump with suction and/or delivery air vessel.
• Traditional construction uses cast iron; modern variants may use steel pressure vessels.
• Connection is near the pump cylinder to be effective.

Concept / Approach:
An air vessel is a closed chamber partially filled with air. It is connected to the pipeline at its base so that water can enter/leave below, compressing/expanding the air cushion above. This arrangement absorbs flow pulsations during stroke reversals and maintains near-uniform pipe velocity.

Step-by-Step Solution:
Identify construction: closed pressure vessel with trapped air.Connection detail: opening at the base into the suction/delivery line near the cylinder.Function: air compressibility stores/releases energy, smoothing the flow and reducing acceleration head.

Verification / Alternative check:
Standard pump texts depict bell-shaped cast-iron vessels mounted vertically with flange at the base connecting to the pipeline tee near the pump body.

Why Other Options Are Wrong:

• Disagree: contradicts the conventional design description.
• Side-specific agreements are unnecessary; vessels can be provided on suction, delivery, or both.

Common Pitfalls:
Assuming the vessel must be at the top or confusing it with surge tanks used on long mains.

Final Answer:
Agree