The partial pressure method itself, from a logical point of view, is really simple and practical: measuring the amount of gases through their pressure, they are added step by step proportionally to the desired composition.
In other words, the assumption is a direct pressure-quantity relationship.
Unfortunately it is not that simple; this is valid only with the Ideal Gas model.
In a nutshell, from the process perspective, to successfully blend a mixture by partial pressures we must focus on the management of three key points:
• The temperature
• The compressibility of each gas
• The molecular interaction between different gases
Tech Gas Blender has this task: to act as an interpreter, making the amount of gases readable by the pressure property.
Of course there are other key components (outside the process - ex measuring instrument), which are taken into account in the section "Errors in Blending".