Two screw rotors inside the cylinder of the COBRA NC rotate in opposite directions. The pumped medium is trapped between the cylinder and screw chambers, compressed, and transported to the gas outlet. During the compression process the screw rotors do not come in contact with each other or the cylinder.Thus, no lubricants or operating fluids are required in the compression chamber. COBRA NC series vacuum pumps use efficient water cooling resulting in an even temperature distribution throughout the pump body, and guaranteeing thermal stability throughout the process.