FIELD OF THE INVENTION

The present invention relates to a device for Anti-slosh waveguide and transducer’s wetting protection arrangement for ultrasonic sensor and methods thereof.

BACKGROUND OF THE INVENTION

It has been seen that there have been many proposals in the past  regarding measurement of the fuel level inside the vehicle’s tanks with ultrasonic level sensors. 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.

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. These transducers are placed inside and at the bottom of the pipe 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. However such a floating sphere needs clearance with the walls of the tubing thereby enabling the sphere to rise and fall freely  which also results in the slosh being able to creep in through this space towards the sensor and wet its surface. Once the surface of the sensor gets wet it tends to provide erroneous readings.

Motions impact 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 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 into a 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 fluids with respect to air so the net result is a false reading indicating full tank to be a quarter tanks etc.

The problem to be addressed is by designing a tube  with plurality hollow long sections disposed closely with each other  forming a tubular waveguide and mounting the ultrasonic transducer at its top. The said tubular waveguide is inserted inside the tank to take the measurements of the fluid level wherein its plurality hollow long sections distributes the surface level of the fluid under measurement into plurality smaller sections. This stops them from combining with each other and thus reducing the slosh substantially. A low slosh in the tubular waveguide also keeps the surface of the sensor dry thereby enabling precise measurement to be taken on mobile applications.

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. As the waveguide makes the surface under measurement smooth the tubular waveguide works equally well with non-invasive (through the wall) ultrasonic sensors.

The invention relates more particularly to ultrasonic type level sensors on aircrafts  boats  and locomotive fuel tanks but not by way of limitation  to such apparatus and method utilizing other sensors such as radar level sensors  optical 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 provide a tubular waveguide with plurality hollow sections  in front of an ultrasonic transducer  to divide the surface of the fluid under measurement into multiple smaller sections thus reducing individual slosh levels and also as the force acting on the fluid surface gets divided into smaller magnitudes and hence the resultant slosh gets reduced significantly.

It is another object of the invention to stop the fluid under measurement  from washing the surface of the sensor  thereby improving the sensor performance substantially.

It is another object of the invention to insert the tubular waveguide directly from the top of the tank to measure the level of the fluid accurately under mobile conditions.

A still further objective of the invention is to provide hollow sections of varying diameters placed either adjacently or concentrically as a singular tube.

With the above and other objectives in view  as will hereinafter appear  various embodiments of the present invention are described hereunder.

SUMMARY OF THE INVENTION

According to an embodiment of the invention  Anti-slosh waveguide and transducer’s wetting protection arrangement for ultrasonic sensor; a tubular waveguide comprising of plurality hollow section running throughout its length and is immersed in the fluid whose level is required to be monitored. The plurality hollow sections of different diameters and shapes divides the surface exposed to the ultrasonic transducer into plurality smaller surfaces; these surfaces under the influence of external force produces correspondingly very low level of slosh in each segment hence the net slosh produced becomes significantly lower for the ultrasonic sensor to make precision measurements. The tubular waveguide is spaced at a convenient distance from the ultrasonic transducer through a vent rings having plurality holes  to remove the built up of air pressure due to rising fluid levels. A similar vent ring is also placed at the bottom of the tubular waveguide to cater for any obstruction from the tank bottom surface. The tubular waveguide is able to reduce the slosh and keep the ultrasonic transducer away from getting wet  thereby enabling precision measurements of the fluid level to be taken  even under extreme slosh and vibrations  effectively and reliably.

According to another embodiment of the invention  a tubular waveguide with plurality hollow sections is mounted in front of the ultrasonic transducer spaced at a convenient distance through a vent ring.

According to another embodiment of the invention  the tubular waveguide is dispose with plurality smaller sections running throughout its length to permit the fluid to rise inside.

According to another embodiment of the invention  the hollow sections comprise of plurality hollow sections with varying diameters/ shapes and placed adjacently in a contiguous manner.

According to another embodiment of the invention  the plurality hollow sections can be disposed concentrically.

According to another embodiment of the invention  the ultrasonic sensor is provided with an additional power amplification stage to cater for any signal strength attenuation.

According to another embodiment of the invention  the tubular waveguide prevents the fluid under measurement from washing the surface of the sensor  thereby improving the sensor performance and reliability substantially.

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 sensor is mounted on the top of the tubular waveguide.

Figure 2 shows a detailed view of the tubular waveguide as attached to the ultrasonic transducer.

Figure 3 shows a detailed view of the tubular waveguide as mounted on the tank with a tilt.

Figure 4 shows a detailed view of the tubular waveguide as mounted on the tank with a non-invasive ultrasonic sensor.

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 mounted on the main tank 3  for liquid level measurement. A tubular waveguide 1  is attached to the ultrasonic transducer 7  of the ultrasonic sensor 2   separated appropriately through vent ring 10  that has holes to vet any pressure development inside the tubular waveguide 1  due to rising fluid and similarly a vent ring 10  at it bottom to allow free flow of liquid level inside the tubular waveguide 1. The tubular waveguide 1  comprise of plurality hollow sections 9  running along its length and thereby enabling the fluid 4  to rise inside. When the main tank 3  is mounted for mobile application and is under the influence of the external force the fluid 4  inside the tank moves randomly causing slosh 5. The ultrasonic sensors 2  requires a flat surface in order to make accurate measurements  any slosh in the fluid 4  surface disturbs the accuracy of measurement. The tubular waveguide 1  is disposed with plurality smaller hollow sections 9  running along the length of the tubular waveguide 1  thereby distributing the surface level of the fluid under the transducer 7  into plurality smaller sections. This stops the fluid surface from combining with each other and the smaller hollow sections 9  further minimizes the slosh level in each sections and thus reduces substantially the resultant effect of the slosh 5  and presents an average level 6  of the fluid inside the tank for measurement. The tubular waveguide 1  is thereby able to keep the surface of the transducer 7  dry by preventing the fluid from washing the surface of sensor which induces significant errors in the reading by altering the response of the transducer 7. The system  hence  is able to make precise  accurate  reliable measurements of the liquid level inside tanks 3  mounted either on the mobile vehicles or the applications where the structure supporting the tank 3  are subject to extreme level of vibrations.

As can be seen in Figure 2  it shows the detailed view of the tubular waveguide 1  as mounted with the transducer 7. The tubular waveguide 1  of appropriate diameter and length has hollow sections 9  disposed along its entire length. The tubular waveguide 1  is spaced at a small distance from the transducer 7  through a vent ring 10  with plurality small holes 11. This arrangement helps to prevent pressure buildup inside the tube when the fluid rises inside it. Another vent ring 10  of appropriate dimensions matched with the tubular waveguide 1  is disposed at its bottom to enable free flow of fluid at it bottom surface. The transducer 7  is mounted with an electronic signal conditioning circuit 8  to enable it take measurement and compute and present the results. The signal conditioning circuit 8  is provided with an additional power amplification stage to cater sound pressure level loss caused by the attached tubular waveguide 1.

As can be seen in Figure 3  it shows the elements of the present invention  as mounted on the main tank 3  for liquid level measurement. This arrangement shows where the tubular waveguide 1  is mounted at an angle with respect to the fluid 4  level under measurement. The plurality hollow sections 9  of the tubular waveguide 1  presents a level surface 6  to the transducer 7  for accurate measurements wherein the each hollow sections 9  provides smaller individual tilt surfaces   which doesn’t affect the accuracy   performance of the measurement.

As can be seen in Figure 4  it shows the elements of the present invention  as mounted on the main tank 3  for liquid level measurement. This arrangement shows where the tubular waveguide 1  is mounted with a non-invasive ultrasonic sensor 12  at its bottom at the bottom end of the tubular waveguide 1  through proper media isolation arrangements. The non-invasive ultrasonic sensor 12  injects the ultrasonic waves from the bottom of the tubular waveguide 1  and receives the echo from the inner surface of the fluid 4  under measurement.