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Shown above is an example graph pulled from a regulator’s company datasheet
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Shut-off Valves
“Shut-off” valves really just refer to all valves in the system that serve as gates to the flow. We add valves to our system to have control over different steps of operation. This includes propellant tank pressurization, engine firing, system venting, propellant filling, and anything in between. The below table provides a brief overview of some types of shut-off valves that are often used in a simple pressure-fed engine feed system. Note: although I literally just found these pictures off google, choosing valves for your system is a CRUCIAL (and surprisingly fun) area of design for pressure-fed engines. In industry, things get even more interesting, as it is common to design custom valves in-house.
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One of the main things to consider when choosing valve components is the resulting pressure drop through the valve. This is important to consider because if we have many valves in our system that cause large pressure drops, the resulting pressure at the engine inlet will be much lower than desired. A COTS (commercial off-the-shelf) valve will usually have an accompanying flow coefficient from its datasheet. If you know the basic characteristics of your feed system, you can use the flow coefficient equation (discussed earlier) to calculate the pressure drop across each valve and ensure your valve pressure drops are not detrimental.
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Pressure Relief Components
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