According to different types of hydraulic pumps, the relationship between pressure and flow is also different. For a constant power pump, the product of pressure and flow is power, and power is constant. The higher the pressure, the lower the flow, and vice versa. For a constant pressure pump, the pressure should be kept constant regardless of the flow rate. For load-sensitive pumps, the pressure is only related to the size of the load, and has nothing to do with the size of the flow, but the maximum power of the motor limits the maximum value of the product of pressure and flow. For the pipeline of the system, the greater the pressure difference between the two ends of the pipeline, the greater the flow.