two rotors 208 and 210 fig2 shows a compressor 302 which has a suction pipe 382 connected to the suction side of the compressor the compressor 302 has a discharge pipe 378 which is connected to an oil management system 376 from which refrigerant is flowing to a pipe 380 in the compressor 302 one of the rotors 308 and 310 can be seen a slider 322 can also be seen this slider has a front area 324 which engage the rotors 308 and 310 the slider has a backside 328 which is placed in a working chamber 380 the working chamber 330 is connected to the chamber 333 through a flow restriction 370 from chamber 333 there is a connection towards the compressor to a point in the compressor having a relatively low pressure p 4 the chamber 330 is further connected to a line 371 to a magnetic valve 372 and further to a line 374 to the oil management system 376 in operation the discharge pressure p 2 will be present at the area a 1 which is the front of the slider 322 this pressure p 2 working on a 1 will press the slider backwards in the chamber 333 a pressure p 4 is operating which is slightly above p 1 which is the.