How could we measure the "drag pressure"?

You are always requested to measure the drag pressure with pipes stayed in the machine. Simply speaking, completely open the machine carriage, zero the pressure in the hydraulic system, close the pressure relief valve, then push the direction lever to maximum and gradually rotate the pressure regulated valve in a clockwise way until the machine carriage gets in motion. The current pressure shown on the gauge is the drag pressure. For more details, please refer to Riyang operation manual for butt fusion machine.