Adjusting the discharge valve: This is the most common method; partially closing the discharge valve increases pipeline resistance, thereby raising the pump's discharge pressure.
Adjusting pump speed: The motor speed is regulated using a variable frequency drive (VFD) to alter the pump's flow rate and head. Reducing the speed decreases both flow rate and head, while increasing the speed raises them. This method offers significant energy savings but requires VFD equipment.
Changing impeller diameter: Reducing the impeller diameter lowers the pump's head and flow rate, thereby adjusting the pressure. This method is suitable for applications requiring long-term pressure adjustment.
Adjusting the number of stages in a multistage pump: For multistage pumps, the total head-and thus the pressure-can be adjusted by adding or removing stages.
Bypass regulation: A portion of the fluid is recirculated to the suction side via a bypass line; this reduces the discharge flow rate, thereby increasing the discharge pressure.
