Pneumatic and Hydraulic Pressure Sensors and its application.
Pressure Sensor
Technology:-
Pneumatic and hydraulic sensors are transducers that
generate an electrical signal in proportion to the measured pressure. This
allows you to control the pressure with a variety of electronic devices.
The most popular technology for pneumatic and hydraulic
sensors uses a physical diaphragm made of silicon, which bends under pressure.
The diaphragm is a tension meter, whose electrical resistance changes when the
force is applied, in which case the electrical resistance varies due to the
pressure exerted by the air, gas or hydraulic fluid of the sensor. This
resistor is used to modify the sensor output voltage.
Some pressure sensors for power steering applications use
linear variable differential transformers. This includes a core that moves
inside the hollow tube and monitors the movement of the high precision
directional control valve, allowing hydraulic oil to flow to other areas of the
system.
Many pressure sensors are now independent, integrating all
the necessary electronics and temperature compensation technology into the
device.
However, this is not always possible, since the pressure
used in hydraulic systems increases, increasing efficiency and making the
entire system smaller and more compact. An alternative is the built-in sensor,
in which the electronic components are separated from the sensor itself. This
allows the sensor to work in environments characterized by high temperatures,
vibrations and radiation.
To resist harsh environments, pressure sensor chips are
designed so that the medium (gas or liquid) comes into contact only with
silicon to protect electronic components.
Some pressure sensors for pneumatic and hydraulic pressure
work by measuring the expansion of a flexible tube, not the pressure of a gas
or liquid. This allows you to detect blockages in the tube and monitor the
performance of the pump.
Measurement options:-
Like other types of pressure
sensors, sensors used in pneumatic and hydraulic devices can measure
differential pressure (the difference between two pressures) or absolute
pressure (measured against zero or other absolute value).
In the pressure regulator, the differential pressure sensor
compares the pressure on both sides of the valve to determine if the inlet flow
is equal to the outflow.
Applications:-
Examples of systems based on pneumatic technology include
vehicle tires, air brakes (buses, trucks and trains), air compressors,
compressed air engines, vacuum pumps, etc.
Examples of hydraulic devices include vehicle braking
systems, power steering systems, shock absorbers, utility vehicles such as
excavators and aerial platforms, and industrial machines such as elevators and
hydraulic presses.
The most important application of pressure sensors in
pneumatics and hydraulics is to ensure that the pressure in the system is
within the correct level or the optimum range.
This is especially important for hydraulics, where the
liquid in the system is volatile or flammable (for example, mineral oil) and
reaches very high pressures and temperatures, which can lead to leaks and
accidents.
The pressure sensor works like an automatic valve (see
figure below) designed to control the pressure of a part of the pressure
regulator or system. Pressure regulators adjust the demand for gas or liquid to
the needs of the system while maintaining a constant output pressure. As the
system requires more power, the load flow must increase and the regulator flow
must increase. Otherwise, the controlled pressure drops.
Options and
specifications of Pneumatic and Hydraulic Sensor:-
Pneumatic and hydraulic sensors generally have a pressure
range that can be measured, for example, 0-200 bar. In addition, you can
specify a temperature range (for example, -40ºC to 85ºC) that allows the device
to provide safe pressure limits and accurate readings that can cause a
malfunction.
Most pneumatic and hydraulic sensors specify an error band
(for example, ± 0.05%) that indicates the level of accuracy of the sensor.
Other options include input and output connection types and
physical specifications such as output signals, materials (including parts in
contact with the liquid), thread sizes and sizes.
Limitations:-
Hydraulics in particular is used in harsh and demanding
environments that contain extreme heat, water, dust and radiation. The
hydraulics of large vehicles can be affected by physical shocks and vibrations,
and sudden pressure spikes can also occur. Therefore, the pressure sensor must
be able to withstand these conditions and continue to function properly.
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