How to reduce or eliminate the noise of water treatment equipment and pipelines for dialysis?

The opening of mechanical valves is directly related to the impact or friction between water and valves, so noise is generated. There are many solutions, such as changing the operation mode of the water pump to frequency conversion (to meet different water demand) and adding sound insulation devices (sound insulation felt), but it has nothing to do with your pipe diameter, because what you need is flow, and the noise comes from the valve, not the pipe wall.