Fluid machine and operating method thereof

A fluid machine, comprising:

• a main body (1), internally divided into a low-pressure chamber (11), an intermediate-pressure chamber (12), and a high-pressure chamber (13), sequentially interconnected to each other;
• a screw set (2), comprising a pair of first screws (21) accommodated in the low-pressure chamber (11) and engaged with each other, and a pair of second screws (22) accommodated in the high-pressure chamber (13) and engaged with each other, wherein a first contact line (Z1) is defined between the pair of first screws (21), and a second contact line (Z2) is defined between the pair of second screws (22);
• a drive module (3), disposed in the intermediate-pressure chamber (12), wherein the drive module (3) is connected and configured to drive one of the first screws (21) and one of the second screws (22) to rotate coaxially;
• a capacity adjustment mechanism (4), comprising a first slide valve (41) movably disposed corresponding to the first contact line (Z1) and a second slide valve (42) movably disposed corresponding to the second contact line (Z2);
• an intermediate pressure sensor (5), disposed in the intermediate-pressure chamber (12), wherein the intermediate pressure sensor (5) is configured to obtain an interior pressure of the intermediate-pressure chamber (12);
• and
• a controller (6), connected to and configured to drive the first slide valve (41) and the second slide valve (42) to move, wherein the controller (6) is configured to adjust relative position between the first slide valve (41) and the pair of first screws (21), and adjust relative position between the second slide valve (42) and the pair of second screws (22), based on a rotational speed of co-axial rotating of one of the first screws (21) and one of the second screws (22) and a value of the interior pressure;
• wherein the low-pressure chamber (11) comprises an intake port (16), and the high-pressure chamber (13) comprises an exhaust port (17), each first screw (21) comprises a first suction end (211) and a first discharge end (212) at two ends, each second screw (22) comprises a second suction end (221) and a second discharge end (222) at two ends, the first slide valve (41) comprises a first low-pressure end (411) arranged on one end thereof corresponding to the first suction end (211) and a first radial notch (412) arranged on another end thereof corresponding to the first contact line (Z1), the second slide valve (42) comprises a second low-pressure end (421) arranged on one end thereof corresponding to the second suction end (221) and a second radial notch (422) arranged on another end thereof corresponding to the second contact line (Z2).