Compound Steam Engines — Crank Arrangement A compound engine with the high-pressure and low-pressure pistons driving two different cranks set 180° apart is known as:

Introduction / Context:
Compound engines expand steam in stages across multiple cylinders. Their mechanical layout—how pistons connect to the crankshaft—affects torque uniformity and the need for a receiver (a connecting volume between cylinders). Terminology distinguishes these arrangements.

Given Data / Assumptions:

• Two cylinders: high-pressure (HP) and low-pressure (LP).
• Cranks are separate and set 180° apart.
• Standard historical definitions of compound layouts.

Concept / Approach:
When HP and LP cylinders drive separate cranks on the same shaft, a receiver between the cylinders accommodates the phase difference and volume flow; this is called a receiver type compound engine. In tandem type, both pistons are in line on the same rod and drive a single crank (0° phase). In Woolf type, the cylinders are combined without a receiver, also sharing a common rod and crank.

Step-by-Step Solution:
Note crank geometry: two different cranks at 180°.Separate cranks imply cylinder phasing and require a receiver volume.Therefore the engine is a receiver type compound engine.

Verification / Alternative check:
Textbook schematics show receiver vessels and valve gear arrangements for the 180° two-crank configuration.

Why Other Options Are Wrong:
Tandem type: uses a single crank; not 180° apart.Woolf type: common rod without receiver; again, single crank.both (a) and (b): mutually exclusive layouts, so incorrect.

Common Pitfalls:
Assuming 'tandem' means two cranks; it actually means two cylinders in line on one rod.

Final Answer:
receiver type compound engine