F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
F04D—NON-POSITIVE-DISPLACEMENT PUMPS
F04D25/00—Pumping installations or systems
F04D25/02—Units comprising pumps and their driving means
F04D25/08—Units comprising pumps and their driving means the working fluid being air, e.g. for ventilation
F04D25/12—Units comprising pumps and their driving means the working fluid being air, e.g. for ventilation the unit being adapted for mounting in apertures
F04D25/14—Units comprising pumps and their driving means the working fluid being air, e.g. for ventilation the unit being adapted for mounting in apertures and having shutters, e.g. automatically closed when not in use
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Engineering & Computer Science
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Mechanical Engineering
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General Engineering & Computer Science
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Structures Of Non-Positive Displacement Pumps
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