10
Getting Started
Using Alicat Pressure Instruments with Liquids
All of these pressure devices may be used with chemically-compatible
liquids, but a few warnings must be taken into account:
1.
Water is about 50 times more viscous than air. This is important
when sizing a pressure controller, as this significant increase in
viscosity requires a larger valve to reach expected flow rates. For
example, a PC-series pressure controller sized to flow up to 25 SLPM
of air will be limited to roughly 0.5 LPM of water (or similar fluid).
2.
The factory PID tuning terms are established using air. It may be
necessary to adjust the PID tuning parameters if you will be using
a controller with liquid. Find more information at
,
or contact us (
) to help you through this tuning process.
▲
Caution:
Please check with Alicat before using
your pressure controller with liquids unless
specifically ordered for this purpose.
Dual-Valve Integrated Vacuum Controllers (IVCD)
IVCDs are similar to our PCD-Series absolute pressure controllers in
functionality and in the navigation menu available on the screen. IVCD
devices are used in applications where precise control of vacuum is
required, and are available with the following sensor packages:
•
10 Torr absolute pressure
•
100 Torr absolute pressure
•
1000 Torr absolute pressure
•
Dual-sensor package
which integrates a 1000
Torr and a 10 Torr sensor,
for increased turndown
Integration of the vacuum sensor,
control valve, and PID algorithm
in a single device eliminates the
need for an external vacuum
sensor and throttle valve in your
system. These devices often
come with 7/16″-20 SAE ports by
default, but they can be ordered with welded VCR®, compression, or
VCO® fittings if required. Process port sizes may change depending on
the valve on your device.
An Integrated Vacuum Controller (IVCD) device
with PCA valves.Note the process port in front.
