What method can be employed to decrease back pressure on a condensing engine?

Using a method to decrease back pressure on a condensing engine is crucial for improving its efficiency and performance. Flowing steam directly into the surface condenser effectively reduces back pressure by allowing the steam to condense quickly and efficiently. This is important because the condenser's role is to convert steam back into the liquid phase, creating a vacuum that facilitates the effective operation of the engine.

When steam enters the surface condenser, it comes into contact with the condenser tubes, where it releases heat and changes state back to water. This process not only helps in maintaining a low back pressure but also enhances the overall thermal efficiency of the system. A lower back pressure allows the engine to operate at a higher efficiency, as the pressure differential between the steam entering the engine and the pressure in the condenser is maximized.

In contrast, while increasing the size of the exhaust pipe or redirecting steam to the atmosphere might have some effects on pressure, these methods do not directly address the core function of a condenser as effectively as allowing steam to flow into it. Moreover, installing a pressure relief valve primarily serves a different purpose, which is to protect the system from over-pressurization rather than actively reducing back pressure during operation.