2880R-LT, 2881R-LT, 2882R-LT
Revision 1.0
P a g e 11 | 28
4.2
Probe Installation
NOTICE
Read the following information
before
installation.
Standard probe entry into a tank is via a 3/4" NPT opening (standard probes) or 1" NPT opening
(heavy duty probes). Flanges and concentric shields are available as options. The entrance
configuration may vary depending on the application requirements.
TO SCREW IN THE PROBE (THREADED ENTRY) USE A WRENCH ON THE LOWER FITTING
ONLY. The probe fittings are compression type with Teflon ferrules assembled by applying torque
between the two sections. The fittings are sealed at the factory to provide a compression seal
capable of withstanding pressure up to 1500 psi / 10342kPa. Once opened they cannot be
reassembled without new ferrules.
The probe should be mounted vertically and parallel to a reference ground surface, which is
typically the vertical wall of the tank or a concentric shield around the probe. The following points
are important when installing the probe:
1-
Reference ground:
This is important for accurate measurements and is typically the metal
walls of the tank. For non-metallic tanks, a concentrically shielded probe is required in which
case the shield provides its own Ground. IMPORTANT: For standard threaded entry and flange
entry probes (without concentric shields), make sure the fittings are clean to ensure a GOOD
ELECTRICAL CONNECTION BETWEEN THE PROBE HEAD ENCLOSURE AND THE TANK
(REFERENCE GROUND).
2-
The distance between the probe and the ground reference:
This only applies to probes
without concentric shields. The closer the distance to the tank wall, the greater the sensitivity of
measurement; too close and bridging problems may occur with more viscous material. The
distance should be greater than 25mm.
3-
The degree of parallelism between the probe and the reference ground:
The probe must
be parallel to the reference ground for a linear output signal. Note: the concentric shield option
is inherently linear due to the concentric shield.
4-
The measurement accuracy may be affected by the temperature change of the material in
the tank.
The amount of measurement error depends on the material. If the temperature
change is excessive, temperature correction may be required. Contact the Arjay representative
for more information.
5-
Agitators or moving objects in the tank:
Moving objects in the tank close to the probe such
as agitator blades, moving baffles etc. appear as moving ground references to a capacitance
probe and will cause measurement errors. In applications where these objects are present, a
concentrically shielded probe should be used.
NOTICE
Install the probe with care. Teflon sheath is used to electrically isolate
the metal probe from the liquid. Damage causing leaks may cause
reading errors.