What makes a fluid flow in a pressurized system? What controls this flow?

In a pressurized system, the fluid flows due to a change
in pressure which can be produced by pistons, pumps, etc. The flow is controlled by the
pipes along which the fluid flows. At the joints the direction of fluid can be changed
with the use of valves. If a pipe splits into two different pipes, valves are located on
both the branches. The fluid flows in the pipes which have open
valves.

In pressurized fluid systems the pipes have been
constructed and joined in a manner that enables them to withstand the high pressures
without getting damaged. As pressurized fluids can be highly corrosive, valves should be
able to withstand high pressures and strains.