Positive Displacement Machines for Compressible Media

Positive Displacement Machines for Compressible Media

Positive displacement machines of various types are very widely used in industry with a variety of applications. These are traditional compressed air technology, process gas technology for the compression of natural gas, as well as the use in biogas plants. The correct selection and design of the appropriate machine type is crucial for the respective application. This ensures high reliability of the positive displacement machines, in the mentioned applications. The necessary basic knowledge, the operating modes, and typical applications of the various types of machines are conveyed in the lecture, whereby a fundamental distinction is made between positive displacement compressors and turbomachinery.

Recommended for 5th semester


  • Classification of fluid energy machines, classification of compressors, area of application
  • Common fundamentals (change of state, compression process, dead space, degree of delivery, efficiency, internal compression, multistage applications)
  • Operating principles of positive displacement compressors (reciprocating piston, diaphragm, sliding-vane, gate valve, liquid ring, scroll, roots, claw, screw compressors)
  • Profile generation
  • Standard atmosphere, humid gases, condensation, standard volume
  • Comparison of characteristic lines of turbo and displacement machines, run-up
  • Technical area of application, historical review
  • Design of roots and screw compressors
  • Lubrication, bearings, sealing
  • Pressure pulsation and noise, design of a simple silencer
  • Vibrations
  • Pipes
  • Control
  • Refrigeration technology
  • Vacuum application
  • Expanding operation, flow measurement
  • Acceptance rules and measurements, technical code, product safety

Recommended Previous Knowledge

Fundamentals of Thermodynamics

Recommended Literature

  • Lecture notes
  • O'Neill, P.A.: Industrial Compressors, Theory and Equipment. Butterworth-Heinemann, Oxford ISBN 0 7506 0870 6, 1993Davidson, J.; Bertele, O.v. (Hrsg.): Process Fan and Compressor Selection. MechE Guides for the Process Industries. ISBN 0852988257, 1995
  • Faragallah W.H., Surek D. (Hrsg.): Rotierende Verdrängermaschinen (Pumpen, Verdichter und Vakuumpumpen). 2nd edition, ISBN 3-929682-36-2, 2004
  • Fister, W.: Fluidenergiemaschinen. Volume 1 1984, Volume 2 1986


An excursion to the Aerzener Maschinenfabrik (AM), including performance measurements on the test bench ("block course") is planned. The lecture takes place as a block course (usually fortnightly).

Type of Examination

Oral exam


Further information about this module can be found via the Online Course Catalogue and Stud.IP. In addition, you must also register your attendance at this course via Stud.IP.