always i read that speed ratio v/v control or maintain the gas pressure and control v/v controls the flow. Actually i don't know how to control flow without changing pressure. Or by other words, what is the difference between pressure regulation and flow regulation? In both cases we control how much the valve is opened. So, is the using of 2 valves only for saftey or it is really a must for proper control?
thank u .
thank u .