Liquid-injected compressor or expander element and method for controlling the liquid injection of a compressor or expander device

A method for controlling liquid injection of a compressor installation or expander installation, w herein the compressor installation or expander installation comprises at least one compressor or expander, w herein the at least one compressor or expander comprises a housing that comprises a rotor chamber in which two rotors are rotatably affixed, said rotors rotating with lobes of the rotors mated together, wherein lubricating liquid is injected into the compressor or expander, wherein the method comprises the step of:

• providing at least two liquid supplies to the rotor chamber of the housing,
• wherein one liquid supply of the at least two liquid supplies is always injected into a first compression chamber or expansion chamber and the other of the at least two liquid supplies is injected into a second or subsequent compression chamber or expansion chamber,
• wherein the first compression chamber or expansion chamber is a gas chamber that is closed off after a gas inlet of the rotor chamber and said second or subsequent compression chamber or expansion chamber being formed after at least one rotor of the two rotors has rotated one pitch or revolution from the gas inlet,
• wherein a first injection point is located on a first helical line formed by a tip of a lobe of a rotor that separates the first compression chamber or expansion chamber from the second or subsequent compression chamber or expansion chamber and a second injection point is located on a second helical line formed by a second tip of a second or subsequent lobe of the rotor that separates the second or subsequent compression chamber of expansion chamber from a successive compression chamber,
• wherein the first injection point and the second injection point, further comprises a number of sub-injection points that each open into the first, or second or subsequent compression chamber or expansion chamber, respectively.