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The pressure gauge should be mounted in the same ori-
entation (vertical or horizontal) as in the process.
The reference pressure gauge (2700G) should be mount-
ed vertically.
For hydraulic comparators prime the fluid with the prim-
ing pump, to remove any bubbles.
Measurement points should be distributed uniformly over
the calibration range. Conveniently source pressure with
a manual pump up to 300 psi, after that use an external
pressure supply.
For gas comparators use the fine needle valve or fine
adjustment screw press to precisely meter the pressure.
With hydraulic models use the screw press to source and
fine adjust the pressure.
The source pressure can be adjusted until the device
under test is reading a nominal pressure or until the
reference gauge reads the nominal pressure.
•
The key to a good experience in using a
hand pump, either pneumatic or hydraulic, is
to test and debug your test setup in the shop
before going to the field. Minimizing the
number of pressure connections minimizes
the probability for leaks. Mount the test
gauge carefully to the test pump in the shop.
•
Be sure to consider the hoses that connect
from the hand pump to the device to be
tested. There are a variety of specialty “no
tools required” connectors to connect to
the test hose to make this easy. If these
connectors are not available be sure to have
a variety of adapters, wrenches and PFTE
sealing tape to be able to connect from the
test hose to the input port of the device for
testing. If using “push fit” hoses it is likely
they will eventually leak. Each time - a push
fit hose is connected, it leaves a mark on the
test hose and eventually does not seal well.
To eliminate the leak cut off the affected
portion of the test hose so there is a clean
surface to connect to. This process will need
to be repeated with use.
•
When attempting to get maximum pressure
out of a pneumatic pump, adjust the fine
adjust vernier all the way to down to the stop
so turning the vernier increases the pressure.
When approaching the target pressure use
the vernier to increase to your target pressure.
•
When using hydraulic hand pumps
remember the thermodynamic effect. Once
any fluid is compressed, the temperature
increases and the fluid expands. This
becomes obvious when pumping to a target
pressure with a hydraulic pump. Once
the target pressure is met the fluid has
expanded. As the fluid cools and contracts
the pressure quickly bleeds down until
it reaches temperature equilibrium, this
can take 5 minutes or more. Once the
temperature stops changing, dial the desired
pressure back in with the vernier adjuster.
STEP
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STEP
2
STEP
3
STEP
4
STEP
5
STEP
6
STEP
7
To perform the test:
Additional resources
For more in depth information about
this application check out these videos
and application notes from Fluke.
Check out the 700G videos.
700G Data Sheet.
Interpreting Specifications for Process Calibrators,
Application Note
TECH
TIPS
43
Pressure Applications