flow rates, temperature and pressure - valves questions

[andrew20441]

Many questions with so little space.

Flow through a valve is directly proportional to pressure and temperature?
Liquid density, flow and pressure are directly related?

Can anyone help with an array of questions i have.....

pressure differential control valves - overview of operation and relation to pressure and temp ( is the temperature increase the pressure and therefore results in the regulation of flow?)

double regulating valves - flow, temp and pressure?

Anyone can help?

[Brian_UK]

Are you relating your questions to water flow through valves?

[andrew20441]

Brian
thanks for your reply. Just wanted a synopsis of valves what systems to use them on and the relationships between the flow/pressure and temperature heat again across FCU/AHU coil....
is there anything quick and easy as a chart or sheet to use for them....
constant flow regualtors on constant flow systems
PICV's on variable flow systems

That kind of thing...

Cheers

ACP

[Josip]

Hi, andrew20441 :)


Brian
thanks for your reply. Just wanted a synopsis of valves what systems to use them on and the relationships between the flow/pressure and temperature heat again across FCU/AHU coil....
is there anything quick and easy as a chart or sheet to use for them....
constant flow regualtors on constant flow systems
PICV's on variable flow systems

That kind of thing...

Cheers

ACP

try this link ....

http://www.danfoss.com/North_America/Products/Categories/

there is not a simple answer to your question ...

of course there are always relations between pressure/temperature or pressure/flow ...


here you have (if you want;)) some software to download ...

http://www.danfoss.com/North_America/BusinessAreas/Refrigeration+and+Air+Conditioning/Software/Product+Selection+Tools.htm


hope this will be of some help to you ...

Best regards, Josip :)

[andrew20441]

ok thats good.
If the valve authority ratio is high eg: 0.9 what is the main cause/effect?
if the valve authority is too low...eg 0. what is the main cause/effect?

Any help would be good.
Andrew

[sterl]

Andrew: You have a good sized topic here. A whole lot dependent on the role of the valves....But to

http://w3.usa.siemens.com/buildingtechnologies/us/en/consulting-engineer/engineeradvantage/Documents/pi-control-valves-vs-hp-control-valves.pdf

http://www.watsonmcdaniel.com/2011Catalog/EngineeringData.pdf

The second one will get you a lot of data in tabular form but the basic equations for control valves is on about the 5th and 6th pages.