Select the pump type best suited for duties requiring very high heads with relatively small discharge (typical of boiler feed to high-pressure systems and precise dosing).

Introduction:
Pumps are matched to head–discharge requirements. Applications demanding very high delivery head but comparatively small flow rates (e.g., boiler feed to high-pressure drums, hydraulic presses, metering) call for machines that can generate large pressures efficiently at low capacity.

Given Data / Assumptions:

• Required head is high; discharge is small-to-moderate.
• Steady, incompressible liquids (e.g., water).
• Preference for positive, reliable delivery against high system resistance.

Concept / Approach:
Reciprocating pumps are positive-displacement machines: head rise is largely independent of flow (within mechanical limits). They easily achieve very high pressures at small discharges. Centrifugal, axial, and mixed-flow pumps are roto-dynamic; very high heads typically require multi-staging or very high specific speed compromises and are less efficient at tiny flows.

Step-by-Step Solution:
1) Map duty: high head, small Q → positive displacement preferred.2) Evaluate pump families: reciprocating achieves target without excessive staging.3) Conclude: reciprocating pump is most suitable.

Verification / Alternative check:
Industry practice: boiler feed at very high pressures often uses reciprocating or multistage centrifugal; at very small flows, reciprocating dominates.

Why Other Options Are Wrong:
Centrifugal/axial/mixed-flow: better for medium-to-large flows and moderate heads unless multistaged.

Regenerative pumps can produce moderate high heads but at low efficiencies and not to the extent of robust reciprocating units for very high heads.

Common Pitfalls:
Assuming “high head” always implies centrifugal multistage without considering discharge magnitude and efficiency at small Q.

Final Answer:
Reciprocating pump