Positive displacement compressor types include:

Positive displacement compressors are characterized by their ability to draw in a specific volume of gas and compress it to a higher pressure. The correct answer indicates a selection of types of positive displacement compressors that align with this principle.

The types referenced in the selected answer most likely correspond to specific designs and mechanisms used in positive displacement compression, such as rotary screw compressors, reciprocating compressors, and possibly others that operate by increasing the gas pressure through volume reduction. Each type has its own operational characteristics and applications, ranging from industrial uses to smaller systems.

In understanding why the selected types fit this category, it's essential to know that positive displacement compressors typically feature mechanisms where the volume of the gas is mechanically decreased, thus raising the pressure as it is pushed into a discharge line. Such compressors excel in applications requiring high pressures and relatively low flow rates.

The types mentioned in the chosen answer effectively cover a broad spectrum of technological designs found within the realm of positive displacement compression. This distinction is important for applications where efficiency, reliability, and operational capacity are critical components in selecting the appropriate compressor for a given application.