Previous in Forum: CO2 Gas Mixer Fluctuation in Wave Bioreactor   Next in Forum: Air Flow Switch That Can Discern Between FWD+REV
Close
Close
Close
14 comments
Rating: Comments: Nested
Associate

Join Date: Apr 2011
Posts: 43

Selection of Valve for Flow Control

10/23/2012 2:21 AM

i have to pass water as coolant through some copper winding (dia for coolant 3.5 mm2),

requirements are: the pressure drop will be 15 bar across winding, flow should be more than 3 L/m.

Q 1: we have pump of 50 bar (constant speed), centrifuge which has min flow rate 5 L/m

i want to control this flow through some valves. can i control flow through this?

Q 2: which valve i should buy, Globe, gate, Needle or any other to control flow

pl suggest

Register to Reply
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

"Almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, vote them!
Guru

Join Date: Oct 2007
Location: India
Posts: 1246
Good Answers: 34
#1

Re: slection of valve for flow control

10/23/2012 2:37 AM
Register to Reply Score 1 for Good Answer
Associate

Join Date: Apr 2011
Posts: 43
#2
In reply to #1

Re: slection of valve for flow control

10/23/2012 3:06 AM

Thanks I don't to buy control valve. i just want to fix flow by manually opening or closing valve at some value. It will restrict the flow and flow rate will change.

Register to Reply
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on.
Posts: 32175
Good Answers: 839
#3
In reply to #2

Re: slection of valve for flow control

10/23/2012 3:52 AM

Why is there a need to restrict the coolant flow to some value below its maximum?

Gate valves will give a lousy adjustment. Go for either a globe or a needle for the application, depending on line size.

__________________
"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Register to Reply
Associate

Join Date: Apr 2011
Posts: 43
#4
In reply to #3

Re: slection of valve for flow control

10/23/2012 5:04 AM

Since the hole in copper conductor is of d=3.5 mm2, the pipe size will be near this.

pump can deliver min 5 L/min, requirement is minimum 3 L/min, but in case we have to work on 3 L /min then perhaps has to reduce the flow.

Register to Reply
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on.
Posts: 32175
Good Answers: 839
#5
In reply to #4

Re: slection of valve for flow control

10/23/2012 5:22 AM

Go for a needle valve for this particular application.

<unsubscribes>

__________________
"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Register to Reply Score 1 for Good Answer
Guru

Join Date: Oct 2007
Location: India
Posts: 1246
Good Answers: 34
#10
In reply to #2

Re: selection of valve for flow control

10/23/2012 4:49 PM

Was I trying to sell you any valve? I was only trying to help you, in selecting a suitable valve yourself, for your application.

Register to Reply
Guru
Technical Fields - Technical Writing - New Member Engineering Fields - Piping Design Engineering - New Member

Join Date: May 2009
Location: Richland, WA, USA
Posts: 21017
Good Answers: 795
#6

Re: slection of valve for flow control

10/23/2012 6:29 AM

The diameter could be 3.5 mm, but not 3.5 mm2. A needle valve will be best.

__________________
In vino veritas; in cervisia carmen; in aqua E. coli.
Register to Reply
Guru
Hobbies - Fishing - Old Salt Hobbies - CNC - New Member United States - US - Statue of Liberty - New Member

Join Date: Mar 2007
Location: Rosedale, Maryland USA
Posts: 5197
Good Answers: 266
#7

Re: Selection of Valve for Flow Control

10/23/2012 7:54 AM

VFD. If the pump volume is more then you need control that flow. In doing so you cut energy cost. Restricting the flow will increase energy cost.

__________________
Life is not a journey to the grave with the intention of arriving in a pretty, pristine body but rather to come sliding in sideways, all used up and exclaiming, "Wow, what a ride!"
Register to Reply Score 1 for Good Answer
Guru

Join Date: Oct 2008
Posts: 42355
Good Answers: 1693
#8

Re: Selection of Valve for Flow Control

10/23/2012 9:09 AM

What makes you think that you will need any restriction? You say you have 15 bar pressure drop across the tubing.

Without knowing what the pump will produce, nobody here can make an intelligent suggestion.

Register to Reply
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on.
Posts: 32175
Good Answers: 839
#9

Re: Selection of Valve for Flow Control

10/23/2012 9:55 AM

The velocity through the tubing is higher than economic for pipe flow by ~+75%.

Flow through the copper winding is laminar, according to those figures. Increasing the diameter of the winding would lead to turbulent flow at a lower velocity, and better heat transfer.

__________________
"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Register to Reply Score 1 for Good Answer
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on.
Posts: 32175
Good Answers: 839
#11
In reply to #9

Re: Selection of Valve for Flow Control

10/24/2012 3:10 AM

...oh, and a lower pressure drop through the coil, giving more controllability at the valve.

__________________
"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Register to Reply
Power-User

Join Date: Dec 2010
Location: Tulsa, OK
Posts: 184
Good Answers: 2
#12

Re: Selection of Valve for Flow Control

10/24/2012 8:43 AM

Kazengg,

First of all you need to indicate whether or not you want modulating control or on-off, next, you need to size the valve for the smallest realistic pressure drop across it, such that it does not make the valve too big yet does not affect your system pressure.

Also you need to define the loop precision and what percentage of deviation is acceptable for your system.

Finally the choice between plug, angle, needle, globe will be an economic criteria since most of these would be applicable for your needs.

Now then sizing the valve most manufacturers will supply the programs, but if it is on-off service, you could take the Cv supplied for each valve and based on calculating the required Cv you could select the appropriate vale.

Finally the actuator, which could be pneumatic, electric solenoid or other, since you have not indicated the function or selection criteria more in detail I would assume that maybe an electric solenoid with a plug valve may work, if you want modulating control I would suggest a globe valve with a small pneumatic actuator.

Register to Reply
Guru

Join Date: Oct 2008
Posts: 42355
Good Answers: 1693
#13
In reply to #12

Re: Selection of Valve for Flow Control

10/24/2012 9:00 AM

See #2.

Register to Reply
Associate

Join Date: Apr 2011
Posts: 43
#14
In reply to #12

Re: Selection of Valve for Flow Control

10/25/2012 12:40 AM

Thanks a lot

Register to Reply
Register to Reply 14 comments

"Almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, vote them!
Copy to Clipboard

Users who posted comments:

Joshi (2); kazengg (3); lyn (2); ozzb (1); PWSlack (4); Tornado (1); vargaalex (1)

Previous in Forum: CO2 Gas Mixer Fluctuation in Wave Bioreactor   Next in Forum: Air Flow Switch That Can Discern Between FWD+REV

Advertisement