Element for compressing a gas and method for controlling such element

An element for compressing a gas,

• wherein the element (1) comprises a housing (2) with an inlet (3) for gas and an outlet (4) for compressed gas,
• wherein the housing (2) encloses a compression chamber (5), which compression chamber (5) is provided in the housing (2) with an inlet port (6) connected to the inlet (3) and an outlet port (7) connected to the outlet (4),
• wherein the compression chamber (5) has a rotor (8) rotatably mounted relative to the housing (2) in such a manner that the rotor (8) divides the compression chamber (5) into several working chambers which are arranged successively in a direction from the inlet port (6) to the outlet port (7) and which are mutually sealed or almost sealed,
• such that on rotation of the rotor (8) in the compression chamber (5) the working chambers are successively created at the inlet port (6), subsequently move in a direction from the inlet port (6) to the outlet port (7), are reduced in volume after termination of a fluid contact with the inlet port (6), and eventually get into adjacent contact with the outlet port (7),
• wherein the element (1) further comprises a first passage (10) configured to be able to put the outlet (4) in fluid connection with a first working chamber in the compression chamber (5), which first working chamber is in such a first position that it is not yet in adjacent contact with the outlet port (7),
• wherein the first passage (10) includes a first overpressure valve (11) configured to open the first passage (10) when a first pressure difference between a pressure in the first working chamber in said first position and a pressure at the outlet (4) exceeds a first preset value and to close it when this first pressure difference is lower than the first preset value,
• wherein
• the first overpressure valve (11) includes a valve body (12) that encloses an internal buffer space (13) with a variable volume that is in fluid connection with the outlet (4) through a constriction (14),
• configured so that, upon opening the first passage (10), this variable volume is reduced and gas is carried from the internal buffer space (13) through the constriction (14) to the outlet (4), and
• so that, upon closing the first passage (10), this variable volume increases, and gas is carried from the outlet (4) through the constriction (14) to the internal buffer space (13).