Introduction
HBLC is an intelligent sensor with a built-in
microprocessor. It is designed to control
refrigerant levels in both low pressure and high
pressure systems. It emits a 4-20 mA signal,
which is proportional to the sensor's set range of
measurement.
Apart from the 4-20 mA signal, the sensor also
has a built-in controller.
The controller can be set-up with all the
parameters necessary for controlling a
modulating motor valve.
The sensor can be delivered with a cable for
direct supply to and control of motor valves.
Measurement Principle
The sensor is a capacitative sensor. The capacitative measurement principle is based on the electrical
properties in the proximity of a capacitor. A capacitor is an electrical component that is capable of building
and sustaining an electrical charge
Principally, a capacitor consists of two plates.
When a charge is applied to a plate, the other
plate will be charged with the opposite polarity
and retain the charge until it has been grounded.
The magnitude of the charge (the capacitance)
that can be generated depends, among other
things, on what is found between the plates.
The substance between the plates is referred to
as a dielectric.
Rather than two plates, the sensor for level
measurement is shaped as a cylindrical rod.
When liquid covers the sensor, the measured
capacity is changes.
The conductivity of a material can vary depending
on temperature, chemical composition, and the
homogeneity of the material, and therefore it can
in some cases require a different factory
calibration.
HB Products sensors are calibrated so that they differentiate between conductive and non-conductive
liquids.
In refrigeration systems, the oil and liquid CO2and HFC are not regarded as conductive fluids, whereas
refrigerants such as ammonia and brine are regarded as conductive.
Design
The sensor consists of a mechanical part and an electronic part. These are easily separated by loosening 2
grub screws, or for mechanisms with mounting tabs, by pressing the electronic part in towards the
mechanical part and turning the housing counter-clockwise until a wave washer pushes it from the
mounted position. The electronic part is designed in accordance with IP65 waterproof rating and so as to
withstand vibrations.
The mechanical part is produced in AISI304/PTFE and tested to withstand high pressure.
Software
The sensor is supplied with the latest firmware.
The sensor is configured with a configuration tool, "HB Tool", using a PC. It is capable of determining the
