Alicat PCU Portable Calibration Unit - Manual (Page 5)

5
Portable Calibration Unit
Thank you for purchasing an Alicat Scientific Portable Calibration Unit (PCU). Please take the time to
find and read the information contained in this manual. This will help to ensure that you get the best
possible service from your instrument.
The Alicat Scientific Portable Calibration Unit (PCU) is designed to accurately measure gas flow rates
of common gases with three separate flow meters with ranges determined by the end user’s needs.
The laminar flow, differential pressure flow meters housed in the PCU are accurate and exceptionally
repeatable devices, making the PCU an excellent portable secondary standard for field flowmeter
calibration.
The PCU’s three separate displays allow you to monitor Temperature, Absolute Pressure, Volume Flow
Rate, and Mass Flow Rate simultaneously. The PCU is also equipped with an RS-232 output port that
can be connected to a computer or other data-logging device.
The Alicat PCU is designed for CLEAN, DRY, NON-CORROSIVE gases.
Connecting the PCU
The inlet and outlet connections to the PCU are located below the displays for their respective flow
ranges (Figure 1).
Inlet connections are located on the left and the outlet connections are located on the right (Figure 1.)
The connections are either 1/8”, 1/4”, 3/8” or 1/2” push-connect style tubing fittings with each fitting
corresponding to a single flow range. Use appropriately sized plastic tubing to connect the flow source
to the corresponding inlet fitting. If necessary, connect the corresponding outlet fitting to the original
source destination with proper tubing.
CAUTION: Push-connect fittings are easy to use, as no special tools are required to make the joints.
However, special attention must be paid when cutting the tube — as the O-ring inside of the
fittings can easily be damaged.
It is essential to use the correct cutter such as a pipe slice for copper pipe or dedicated plastic pipe
cutters for plastic tube — Do not use a saw because any burrs left on the tube can damage the
O-ring and cause the joint to leak!
Cut your tube to the required length using the dedicated plastic pipe cutters, making sure you
have a straight cut with no burrs. Then push the tubing carefully into the fitting on the bulkhead
panel.
Softer polyurethane tubing will work best, as opposed to some of the harder plastic tubings available.
It decreases the chances of damaging the O-rings.
CAUTION: If the outlet fittings are not connected to your piping, the gas being measured will
vent to atmosphere at the outlet fittings! Use protective eyewear!
Never Vent Flammable Gases To Atmosphere!