Liquid injected screw compressor, controller for the transition from an unloaded state to a loaded state of such a screw compressor and method applied therewith

摘要

Liquid injected screw compressor with an inlet valve (6) and blow- off valve (19); a liquid circuit (20) with injector (22); a controller (35) for the transition from unloaded to loaded, whereby when unloaded the inlet valve (6) is closed and the blow-off valve (19) is open, and when loaded the inlet valve (6) is open and the blow-off valve (19) is closed, and whereby during an aforementioned transition, when the injection pressure (p22) is below a minimum threshold, the inlet valve (6) remains closed and is opened with a certain delay (tB-tA) and that there are means to gradually increase the injection during this delay (tB-tA) and to open the inlet valve (6) when the injection pressure (p22) has reached the minimum threshold.