What is the difference between a pressure reducing valve and a pressure limiting valve?

The pressure reducing valve is a valve that adjusts the inlet pressure to a certain required outlet pressure and relies on the energy of the medium itself to automatically maintain the outlet pressure. From the point of view of fluid mechanics, the pressure reducing valve is a throttling element whose local resistance can be changed, that is, by changing the throttling area, the flow velocity and the kinetic energy of the fluid are changed, resulting in different pressure losses, thereby achieving the purpose of decompression. Then, relying on the adjustment of the control and regulation system, the fluctuation of the post-valve pressure is balanced with the spring force, so that the post-valve pressure remains constant within a certain error range.
The pressure limiting valve is to limit the pressure range of the pipeline. Most of them are used for high and low pressure limiting. When the pipeline pressure is too high or too low, the pressure limiting valve will give a signal and the front end will be regulated.
Simply speaking, the pressure reducing valve is simply a decompression valve. The pressure limiting valve regulates the pressure in the pipe to a constant range by boosting and stepping down.