I wanted to know the function of a pressure regulator.. Am using one to control liquid flow rate. Here is my understanding- A pressure regulator can be connected across a valve. The pressure regulator maintains a constant "pressure drop" across the valve so if i set it to give a drop of 10 kPa, whilst the pump provides 800 kPa, the pressure of liquid coming out from the valve will be 790 kpa ("Always maintain a drop of 10 kPa"). The valve is used to control the liquid flow rate - that is the valve is open or closed (by hand revolutions) which changes the area inside the valve changing the liquid mass flow rate. How correct is this?