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FIELD OF THE INVENTION
The present invention relates to anti-slosh arrangement for level measurement
and Methods thereof.
BACKGROUND OF THE INVENTION
It has been seen that there are many proposals in the past regarding
measurement of the fluid level with ultrasonic level sensors in the vehicle tanks.
In the prior arts the inventors had introduced electronic circuits and filters to their
sensors to cater for the slosh factor. This type of electronic filtering is applicable
for medium slosh conditions but when the slosh is high even filtering and
averaging doesn’t provide adequate results. Ultrasonic sensors measure the
level of the fluid by projecting high frequency audio waves directed towards the
surface of the liquid under measurement and then computing the time it requires
for the signal to return to the sensor. A rising or falling fluid level provides
different time periods thereby enabling the sensor to compute its level
effectively. Ultrasonic sensors provide good results when the surface of the fluid
is either at rest or moves slowly. However when the fluid surface moves wildly
the sensor loses tracks of the surface and provides wrong results.
In the prior arts, the inventors had introduced electrical circuits and digital/
analog filters to counter these errors. Inventors had also introduced concept of
pipe mounted on the ultrasonic sensor’s head to reduce the errors generated by
the slosh however a considerable amount of slosh also remains inside the pipe.
Motion impacts the performance of an ultrasonic level sensor, a common
phenomenon being the formation of standing waves in a fuel tank. Wave motion
creates noise in the measured data because the level sensor measures one
distance at the wave peak and another distance during the wave troughs. It
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should be noted that for a typical on highway application, this difference can be
as high as 30% of full scale. Therefore as stated above many inventors in the
past designs compensates for this difference by averaging data and processing
the result through a multi tap finite impulse filter / other filtering algorithms. The
combination of which minimizes the standing wave noise level to a manageable
level with a minimal reduction in the level sensor’s response time.
Another common and very difficult problem to handle in mobile/ highway
applications is when the fuel / liquid washes over the surface of the level sensor
. This results in altering the transducer with to depth sounder, coupling to the
fluid and then measuring the distance to the bottom of the tank and back again.
Thereby consequently increasing the speed of sound as the speed of sound is
roughly 4 times faster in a fluids with respect to air so the net result is a false
reading indicating full tank to be a quarter tank.
US7421895, Fluid level measuring system. This patent teaches a method where
the ultrasonic sensors that could be placed outside the wall of the tank at its
bottom to measure the fluid level, is in-fact placed inside a pipe and at its
bottom , the assembly can be inserted inside the fluid tank to take
measurements of the level. The fluid inside the tube is also subjected to slosh in
highway application. This slosh can also wash off the sensor surface thus
causing wrong measurements.
US5184510, Liquid level sensor, shows a method of placing a buoyantly
supported sphere in a tube to indicate correct level to ultrasonic sensor on its
top in arrangements where the tube is required to be aligned. The spherical float
enables the measurements to be take when the pipe tilts as the spherical float
remains un affected. However the clearance between the float and the pipe
walls permits slosh to wet the sensor thereby making the measurement erratic.
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US4170765, Liquid level sensor. Proposes a tube fitted with acoustic sensor at
its top having a discontinuous region in the tubing to serve as a reference for the
ultrasonic sensor . The fluid inside the tube is also subjected to slosh in highway
application. This slosh can also wash off the sensor surface thus causing wrong
measurements.
The problem to be addressed is by tapping the bottom of the fuel tank with a
small adapter and installing a narrow pipe parallel to the fuel tank with reduced
diameter such that the sensor could be placed on this pipe without taking
considerations for the tank compartments. The pipe is further provided plurality
circular fins on its inner surface along its surface to reduce the fluid sloshing
inside the pipe and placing an ultrasonic sensor on its top to take the
measurements more accurately and precisely.
There are ultrasonic sensor of non-invasive type which could be mounded
beneath the tank on its tank wall and these sensors also measure the fluid level
on similar principles but the waves gets reflected from the inner surface of the
fluid. Such type of sensors can equally be benefited from the patent under
discussion.
The invention relates more particularly to ultrasonic type level sensors on
locomotive fuel tanks but not by way of limitation, to such apparatus and method
utilizing other sensors such as a radar level sensor or other similar types on
different type of tanks used in mobile/ vibrating applications.
OBJECTS OF THE INVENTION
It is therefore the object of the device to enable the placement of a sensor at a
convenient location where the fluid tanks comprise of multiple compartments
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and at location inaccessible for the sensors from its top side, by the placement
of adapter at the bottom of the tanks and placing a parallel tube along the height
of the tank. The tube is provided with a narrow beam ultrasonic sensor at its top
to measure the level of the fluid rising or falling inside the tube which in-fact
represents the tank level. The tubing is further provided with plurality concentric
hollow rings and plurality vertical fins at its inner surface at appropriate spacing
to reduce the slosh arising in the tube, thereby providing accurate measurement
of liquid level.
It is another object of the invention to provide a device and method to access the
fluid level inside the tanks which are inaccessible from the top surface for the
ultrasonic/ like sensors by attaching a vertical tube outside the tank.
It is another object of the invention to provide an ultrasonic sensor which uses
narrow beam for level measurement on the top end of the tube .
A further objective of the invention is to provide plurality hollow circular fins
attached concentric to the tube along with plurality vertical fins to remove slosh.
A still further objective of the invention is to distribute the plurality concentric
rings as said on the entire inner length of the tubing.
A still further objective of the invention is to provide an ultrasonic level sensor
with significantly higher power output to compensate for the loss in power arising
from the attenuations caused by the plurality circular fins and vertical fins.
With the above and other objectives in view, as will hereinafter appear, various
embodiments of the present invention are described hereunder.
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SUMMARY OF THE INVENTION
According to an embodiment of the invention, Anti-slosh arrangement for level
measurement comprises; a tube arrangement having a tap at the bottom of the
tank and ventilating holes at its top and placed parallel to the tank, wherein the
tube and the tank works like a ‘U’ shaped tube and represents the tank level in a
smaller cross-section area with reduced slosh level; an ultrasonic sensor with
narrow beam width of measurement mounted on the top of the tube to measure
the fluid level inside the tube at any given instant of time. The tube further
comprising plurality hollow circular fins and placed concentrically inside the pipe
and plurality vertical fins along its inner length and distributed along its length at
convenient spacing to mitigate the slosh inside the pipe thereby enabling precise
measurements of fluid level even in heavy sloshing environments.
According to another embodiment of the invention, a tube with small crosssection
area and parallel to the tank is provided which is tapped at the bottom of
the tank such that it could be conveniently located at other place in applications
where the tanks are inaccessible from the top surface for the ultrasonic/ like
sensors.
According to another embodiment of the invention, the tube has ventilation holes
conveniently located on its top to enable this tube work like one end of the ‘U’-
shaped tube thereby representing tank level.
According to another embodiment of the invention, an ultrasonic sensor is used
which uses narrow beam for level measurement on the top end of the tube.
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According to another embodiment of the invention, the tube is provide with
plurality hollow circular fins of appropriate width attached concentrically to the to
the inner side of the tube along its entire length.
According to another embodiment of the invention, the tube is provide with
plurality vertical fins of appropriate dimensions attached vertically to the inner
side of the tube along its entire length.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 shows a detailed view of various components of the invention
according to an embodiment of the present invention where the tube is mounted
external to the tank.
Figure 2 shows a detailed view of various components of the inner structure of
the tube.
Figure 3 shows a detailed view of various components of the invention
according to an embodiment of the present invention where the tube is mounted
inside the tank with ultrasonic sensor at its top.
Figure 4 shows a detailed view of various components of the invention
according to an embodiment of the present invention where the tube is mounted
inside the tank with a non-invasive ultrasonic sensor.
For a better understanding of the embodiments of the invention and to show
how it may be performed, it will now be described in more detail with reference
to the accompanying drawings.
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DETAILED DESCRIPTION OF THE INVENTION
The present invention can be better understood by reading the following detailed
description of some of the embodiments, with reference made to the
accompanying drawings. It will be understood that a particular system
embodying the invention is shown by way of illustration only and not as a
limitation of invention. The principles and features of this invention may be
employed in various numerous embodiments without departing from the scope
of the invention. References are made to accompanying drawing in which its
novel feature and advantages will be apparent.
As can be seen in Figure 1, it shows the elements of the present invention as
attached to the main tank (7) for liquid level measurement. There are many
places where the fuel tanks are inaccessible from the top surface of the tank and
yet requires explosion proof methods for level measurement and that too in
operating conditions which provides large amount of slosh. Such tanks have pre
installed partitions inside to reduce slosh. This makes the placement of the
sensors more difficult. To overcome this present invention uses an external tube
3, which is placed parallel to the tank’s height, providing a smaller diameter as
compared with the tank and is connected to the bottom of the tank through
connecting pipe 4, of desired length which enables the placement of the tube at
different location to the tank. The external tube 3, is provided with ventilation
holes 8, on its top surface to enable the free rise and fall of the fluid thereby
working as a ‘U’ shaped tube but with significantly reduced diameter. The
external tube 3, is attached with an ultrasonic sensor 1, at its top side emitting
narrow beam ultrasound for level measurement. The external tube 3, reduces
the slosh considerably due to its reduced surface area as compared to its main
tank 7, but it is yet not enough for good measurements, to overcome this
plurality hollow circular fins 2, are attached to its inner side and along its entire
length at convenient spacing to obstruct the movement of the fluid 5, along its
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walls. Similarly plurality vertical fins 10, are also provided in this arrangement at
convenient spacing to obstruct the movement of the fluid 5, in circular direction.
These arrangement reduce the slosh substantially, thereby enabling precise
measurements of the fluid 5, level to be take during the run. The tube 3, could
also be disposed with non-invasive type ultrasonic sensor appropriately
mounted at its bottom.
As can be seen in Figure 2, it shows the elements of the tube 3, in greater
details. Plurality hollow circular fins 2, with appropriate inner and outer diameter
and thickness are placed on top of each other duly spaced along the entire inner
length of the tube 3, concentrically. It also has plurality vertical fins 10, disposed
between two consecutive hollow circular fins 2, to provide spacing and also
prevent circular motion of the fluid.
As can be seen in Figure 3, it shows the elements of the present invention as
attached to the main tank (7) for liquid level measurement. This arrangement
shows the mounting of the tube 3, inside the tank with its bottom opened
appropriately to allow the fluid 5, to rise inside freely. All other measurement
principals remaining the same.
As can be seen in Figure 4, it shows the elements of the present invention as
attached to the main tank (7) for liquid level measurement. This arrangement
shows the mounting of the tube 3, inside the tank with non-invasive ultrasonic
sensor 9, disposed at the bottom of the tube 3, after taking care of media
isolation.
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I Claim:
1. An Anti-slosh arrangement for level measurement, comprising:
A tube (3) placed externally or internally in the tank (7) with
ventilating holes(8) at its top and/or bottom to allow for free rise and fall of
fluid(5) whose level is required to be measured; Wherein
the said tube(3) further comprise plurality hollow circular fins (2) placed
concentrically and distributed along the entire length of the tube(3) at
convenient spacing; wherein
the said tube(3) is further disposed with plurality vertical fins(10) of
appropriate height serving as spacers and circular movement restrictors for fluid
(5), and disposed between two adjacent hollow circular fins (2); thereby
the arrangement reduces the slosh inside the pipe significantly; and
a narrow beam ultrasonic sensor(1) mounted on the tube (3) to
measure the fluid level inside the tube precisely at any given instant of time.
1. The device as claimed in any one of the preceding claims, wherein the
said tube(3) comprises, plurality hollow circular fins(2) of 1~4mm
thickness with appropriate diameter and placed concentrically in the
inner surface of the tube(3) and distributed along its entire length.
2. The device as claimed in any one of the preceding claims, wherein the
said tube(3) comprises, plurality vertical fins(10) of 1~4mm thickness
having width equal to the width of the plurality hollow circular fins(2) and
disposed vertically serving as spacers between the two adjacent hollow
circular fins(2) along its entire length.
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3. The device as claimed in any one of the preceding claims, wherein the
tube (3) can be disposed on the main tank (7) by connecting it to its
bottom with a connecting pipe(4) such that the tube (3) could be placed
externally, away from the main tank(7).
4. The device as claimed in any one of the preceding claims, wherein top
end of the tube(3) can be mounted with an ultrasonic sensor(1) which
uses narrow beam ultrasound for level measurement.
5. The device as claimed in any one of the preceding claims, wherein the
tube (3) can be used with other type of level measurement sensors such
as radar, laser, optical levels sensors in particular and even with other
types of the sensors.
6. The device as claimed in any one of the preceding claims, wherein the
said tube (3) can be interfaced with the non-invasive ultrasonic sensor (9)
disposed at its bottom, with appropriate media isolations, along with
ventilation holes(8) at its bottom and top.
7. An anti-slosh arrangement for level measurement and Methods thereof,
substantially as herein described and illustrated in the figure 1, figure 2,
figure 3 and figure 4 of the accompanied drawings.