User’s & Technical Manual –
P/I LEVEL TRANSMITTER PIT7000
GELEC
Industrial Electronics
PAGE
14
BUBBLE TUBE
A thin tube should be firmly installed in the tank with its nozzle
submerged in the measured fluid. A small volume of air is
provided to this tube
through the device’s airflow regulator
and connection pipes, escaping into the fluid in a form of
bubbles.
The device measures the hydrostatic pressure at
the point where the bubbles are released.
At the bottom side, the tube
’s nozzle
must have
a smoothed
V-notch
, in order to assist the release of a controlled and
constant stream of small bubbles (3-4 per second). This is
preferable for consistent measurement, rather than
intermittent large bubbles.
On the top side,
a T-shaped fitting
is needed to connect the
6/4mm tubes which lead to (S) and (O) adaptors of the
PIT7000.
Use standard and compatible pneumatic parts, which meet the
operating requirements of the application regarding pressure,
temperature, safety etc.
The top of the tube must be at least
25cm above the
fluid
’s highest
possible level
, for avoiding fluid suction
towards connection tubes and PIT7000 after air supply cut-
off.
In order to have unaffected measurement, it is very
important to
prevent air leakage in all pneumatic
connections
. Use an appropriate thread sealant in all
threaded elements.
In a common level measurement application, the tube is installed almost at the bottom of
the tank.
Ensure that the provided air can escape freely into the fluid
and the nozzle is
not blocked by the tank body or possible sediment/dirt during operation. Partial blockage
of the nozzle will cause faulty readings and full blockage will lead the compressed air
supply directly to the pressure sensor and damage it.
Do not install the tube deeper than your PIT7000 version allows
. The excessive applied
pressure can cause permanent damage or degradation to the
device’s
pressure sensor.