In this application an accurate control of the pressure itself and a large pressure range had to be covered. Moreover, a suitable control device should be able to deal with high pressures, high temperatures and low flows. As the valve of the pressure regulation needs to be resistant to high temperatures and several different chemicals, a traditional spring-loaded valve is not suitable. Therefore, a dome loaded back pressure regulator can be a good solution. As products can be gaseous as well as liquid, the pressure controller should be suitable for gases, liquids and two phase flow.