device 30 is located comprising a pressure controlled valve 31 see fig4 which allows the fluid to pass if the pressure of the fluid pumped down is greater than the ambient pressure in the well 1 this valve 31 opens up and shuts off the central channel 16 and the annulus 15 simultaneously thereby providing both supply and return flow by means of the pressure control of the valve 31 the result is that when the valve opens the return flow channel opens simultaneously and when the valve closes the return flow channel closes simultaneously in an embodiment the supply and return channels may be supply in the annulus 15 and return in the central channel 16 in addition the pressure controlled check valve may be arranged in combination with a third bypass valve see fig4 for a channel between the return flow channel and the channel for flow into the well this bypass valve 32 is controlled by means of its shape with the result that the bypass valve is open when the pressure controlled valve 31 is closed and the bypass valve 32 is closed when the pressure controlled valve 31 is open the pressure controlled valve may be a check valve a possible physical embodiment for the guide device with the two valves is to mount a ball body 310 in.