# Principles of valves

## Main Question or Discussion Point

Hello to everybody!

I would like to find out how valves work but I cant find detailed information through Google.
Could you tell me on what physical principles their work is based on? Most of all, Im interested in heart valves or their analogs - reed valves. Thank you in advance.

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Integral
Staff Emeritus
Gold Member
Valves? Lots of different kinds of valves, do you mean vacuum tubes or solenoids? Or what?

Do you mean energy conversions like headloss or do you want mechanical construction? What kind of valves?

I mean mechanical valves, especially, reed valves or heart valves. Why do they work so that the liquid or gas flow only in one direction? What prevents the backflow of liquid?

chroot
Staff Emeritus
Gold Member
If you look at a picture of a heart valve, it's pretty self-explanatory.

- Warren

Integral
Staff Emeritus
Gold Member
Heart valves are pretty simple, similar in concept to a "duckbill" valve.

I mean mechanical valves, especially, reed valves or heart valves. Why do they work so that the liquid or gas flow only in one direction? What prevents the backflow of liquid?
Samwell it's just a trap-door.

You can easily push it open from one side,
but you can't do the same from the other side.

i.e. It only pushes open from one side.

Thank you very much guys for explanation!