VALVE SELECTION 1

[amanites]

My project has carbon steel product lines in which soya/rapeseed oil and biodiesel are being pumped at ambient temp and not more than 10 barg.I need flanged valves ASA 150# some manual and some motor operated they are 6" and 10" diameter lines.Will I use butterfly or gate or other for this purpose?There will also be 6" check valves and Im not sure if they will be ball/swing check/single check.
Will my actuators need limit switches or mechanical.Any advice would be much appreciated.
Thanks

 

[BigInch]

I'd use a gate or a ball valve unless you have some reason not to. Your project design specification or company standards should have a Valve Selection Specification or some other specific procedure. Look for that first. You might also get hold of a valve selection guide and review the typical criteria. When selecting individual specific valves for purchase, you should review the detailed manufacturer's product description.

Here's a few basic Valve Selection guides. Note that it says "guide" and the standard recommendations may not apply in all situations. That is only the beginning, as there are also many material options that need to be specified after the basic valve style is determined.

Valve Selection Guides,

http://www.engineeringtoolbox.com/valve-selection-guide-d_35.html

http://www.thevalveshop.com/menu/select.html

Check valve selection may depend on the valves position in the line, the adjacent equipment, the horizontal or vertical orientation, flow direction, speed of action needed, whether positive closure is needed at low pressures, etc.

http://virtualpipeline.spaces.msn.com

 

[JimCasey]

I don't disagree with BigInch, but I will embellish.
Gate valves are cheap. THey are big. They leak. They take a jillion turns and a cheater bar to open or close. SInce they typically have no elastomers, they can tolerate high temperatures.

Butterfly valves are also comparatively inexpensive. With their resilient seats they shut off tightly during their service life. They are much more compact than gate valves particularly in headspace requirement, and they are short face-to-face. Since the shaft seal is rotary the mechanism for packing wear is orders of magnitude less than the packing wear in a gate valve(long-travel rising stem), so butterfly valves are eco-friendly or wallet-friendly if your procees fluid lost to leakage is expensive. And Butterfly valves only turn 90 degrees co it is possible for them to open and close more quickly than a gate. The elastomer seats usually used are temperature limited. When flexible metal seats are used for hi temperatures, they are somewhart fragile.

Ball valves also shut off tightly but they are more expensive. They have a precision-machined stainless steel ball at their heart, and that's a lot of expensive alloy. Same temp limits with resilient seats. All-metallic seats are available for hi-temp but the torque to move the valve increases with metal seats.

 

[JLSeagull]

As you need carbon steel valves at 10 barg maximum design pressure and ambient temperature, you are within the limits for ASME Class 150 flanges in carbon steel.
The 6 NPS and 10 NPS lines per ASME B36.10 are suitable for the use of butterfly, ball or gate valves. These valve patterns are generally suitable for your clean lubricating fluid. I generally recommend lugged or flanged valves instead of flangeless wafer valves that mount between flanges for combustible or toxic material. Your application does not sound very hostile.

Position switches may be desired for interlock logic or operator status displays. The butterfly and ball valves are more suitable for the automated (actuated) valves than gate valves. The position switches are typically used for automated valves; and infrequently used for manual valves. If interested in position switches, visit a few web sites such as the following to see the preferred devices from

http://www.Moniteurdevices.com,

http://www.Topworx.com,

http://www.westlockcontrols.com.