Warren
Globe Valves
Globe
valves have earned their distinction as the preferred control
valve style. The flow path through a globe valve spreads a pressure
drop through the entire device, while other valve styles tend
to concentrate the pressure drop at the vena contracta. The
vena contracta is the place in the final control element where
flowing velocity is at its maximum, and pressure is at its minimum.
It is the place where phenomena such as "flashing",
"choking"
and "cavitation"
originate. Because it slows pressure drop and recovery rates
within its body, the globe valve is more resistant than ball,
plug and butterfly valves to those counter-productive, sometimes
destructive events. This inherent stabilizing characteristic
of the globe valve enhances its ability to control a fluid stream.
Additionally, ball valves have inherently higher dB levels of
audible noise compared to globe valves, contributing to potential
OSHA violations, regardless of the now common characterized
trims.
Valve
Selection
If
a formal valve specification is not available, obtaining most
of the following information can get the discussion started.
You can also use this email worksheet
to have one of our technical support specialists guide you
through the selection process. The same criteria is also beneficial
with a formal valve specification but the selection process
becomes simpler.
•
Identify if valve is a 2-way valve for flow, pressure or temperature
control or a 3-way mixing, bypass or diverting application
• Type of operator – Pneumatic or Electric
• Control Signal (type and value) and any required accessories
• Modulating Service or ON/OFF Service
• Valve size, connections & materials of construction
if important
• Flowing Medium (water, steam, air, etc.)
• Flow Rate required (gpm, lb./hr., scfh, etc.)
• Pressure at the valve inlet (psig - Normal & Maximum)
• Pressure drop available fully open (psid)
• Temperature at the valve inlet (deg. F - Normal &
Maximum)
|
| 
|
