Electric Liquid Level Sensing System

1
Electric Liquid Level Sensing System
Team 8
Abstract The Wayside Top of Rail system
disburses a lubricant, which reduces the curving
forces, rail wear, and energy needed to propel
trains. Internal pumps are self-lubricated and
can fail if the lubricant falls below the intake.
The designed solution is a series of multiple
sensors retrofitted on a current system to
monitor the lubricant level inside the tank. This
robust system includes sensors for temperature,
audio frequency, and Radio Frequency
Identification (RFID). This fail-safe integrated
implementation is designed to shut off the pumps
at a critical level to prevent damage to the
pumps. The sensing system will also provide the
status of the tank locally within the electronics
cabinet.
Design Requirements Norfolk Southern has
requested a liquid level sensing system to be an
effortlessly implementable system onto tanks that
are currently in place. The challenge was to put
this system into operation without modifying the
tank in any way. Any modification, such as
drilling into the tank, will be impractical while
it is operational and filled to capacity. In
addition, debris could enter the pumps causing
damage. The internal level sensing system also
needs to be implemented with caution. The
lubricant has a tendency to bond on other
objects and solidify when exposed to air for an
extended period. The other objective is to
utilize a small amount of power since the whole
system, including the new liquid level sensing
system, runs off a car sized battery that is
charged by a solar panel.
End-Product Description The final design that
has been developed consists of three types of
sensors. The first sensor is an audio frequency
sensor. This sensor consists of a solenoid that
strikes the side of the tank and a microphone
that picks up the audio vibration. The audio
data is then processed to find if the lubricant
level is at the critical point. The next sensor
is a temperature- based sensor. This sensor
consists of multiple temperature sensors that
read the temperature at different levels. Based
on the temperature at each location, it can be
determined if the pump must to be shut off. The
last sensor is a magnetic reed switch and float
sensor. This sensor consists of a floating
magnet on an track that triggers the magnetic
reed switch to shut off the pump. The data from
the three sensors are interpreted by a digital
signal controller to improve the accuracy of the
system. The purpose of having three sensors is
for intermittent error correction to ensure the
pump runs as much as needed Without allowing pump
failure.
Introduction Norfolk Southern Corporation has
implemented the Wayside Top of Rail systems that
dispense lubricant onto train tracks to reduce
friction. The lubricant inside the tank must not
sink below the pump intake level. This situation
causes air to enter the pumps leading to
malfunction. The locations where these systems
are installed have a refilling schedule that
is hard to implement due to varying
track use and track location.
Craig ZofchakManager
Michael DowWebmaster
Nicholas VogtmannDocument Prep
George BalliosLab Coordinator
Final Product/Project Results When collecting
data from our final product we have concluded
that the magnet float sensor is the most
accurate, but it is required to have some
internal components. The audio frequency sensor
does have a variance when the water level reaches
the critical, but it has room for improvements
based on the frequency dose not vary enough. The
temperature sensor has a good theory to back it
up, but the fact that it requires a lot of time
to computer the different level leaves room for
improvement. The fact that each one has a minor
flaw is why we decide to implement them all
together to make a more robust system.
Prof. Virginia AyresFacilitator
Budget Budget Budget Budget
Qty Part Unit Price Total
1 Digital Signal Controller 4.26 4.26
1 PCB (Estimate) 50.00 50.00
1 Suction Cup Microphone 11.99 11.99
1 Magnetic Reed Switch 14.32 14.32
1 Neodymium Iron-Boron Magnet Pack 29.99 29.99
6 Precision Temperature Sensor 2.89 17.34
1 Plastic Enclosures 6.82 6.82
1 Miscellaneous Parts (Estimate) 20.00 20.00
Grand Total 154.72
Kevin ConnSponsor