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Author Topic: How does a tank apply pressure without water movement in a closed system?  (Read 1827 times)

Offline thedoc

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Mike Malone asked the Naked Scientists:
   
Please read the following forum Q&A on a PONPC (point of no pressure change) I have on a heating system with a circulator and the expansion tank connected to it, assuming the temp is a steady 100F.

Can you explain how the tank can apply pressure without any movement on a closed system?

http://www.heatinghelp.com/forum-thread/147640/pumping-away-PONPC

Sincerely, Mike Malone

What do you think?
« Last Edit: 22/12/2013 18:30:02 by _system »


 

Offline CliffordK

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Most well tanks, and expansion tanks have a rubber bladder, and an air filled area around the bladder.  The air can be pressurized to assist with providing dynamic pressure to the system. 

Fill the system with water using a pump up to a certain pressure, and the pressure tank allows a portion of the pressure to drop as the tank is emptied.  With a solid steel tank, the pressure would drop too quickly, and any air in the tank would eventually be lost.

A one-way valve can aid with forward circulation of the water.
 

Offline Pmb

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Quote from: CliffordK
Most well tanks, and expansion tanks have a rubber bladder, and an air filled area around the bladder.  The air can be pressurized to assist with providing dynamic pressure to the system. 
What is an expansion tank?
 

Offline Bored chemist

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Offline JP

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http://en.wikipedia.org/wiki/Expansion_tank
Was that so difficult?


Between Wikipedia and lmgtfy.com, I don't think we need a TNS forum anymore.  :)
« Last Edit: 24/12/2013 15:51:26 by JP »
 

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