DESC:FIELD OF INVENTION
The present invention relates generally to level sensing of liquid. More particularly, the present invention relates to a Hall Effect level sensing device with double magnets for sensing liquid level present in a container. Advantageously, the present invention eliminates isolation layer formation between the sensing device and contact material due to adulterated fluid or chemical reaction between fluid and the sensing device.

BACKGROUND OF INVENTION
A level sensor is generally used to sense the level of fluid in a tank. There are two kinds of level sensors like contact type and non-contact type. In contact type sensors, wire wound, Thick Film Resistor (TFR) technologies are used and in non-contact type sensors, reed switch, capacitance, ultrasound etc. technologies are used.

Contact type sensors are widely used in small segment automobiles like two wheeler, four wheeler fuel level sensing, Genset fluid level sensing, etc. Signal will be generated when spring contact applies pressure on sensing system in case of the contact type sensor. Contact type sensors are widely used where fuel tanks are non-linear or complicated profiles. Non-contact type sensors are widely used in heavy vehicle application, Genset etc. Signal from the sensor with reference to the level is generally fed to a display unit or Electronic Control Unit (ECU) to process further to display the level or to control other applications. Some of the non-contact type level sensors are not suitable for some types of fluids like conducting mediums, dark mediums, high viscous mediums etc. Non-contact type sensors are widely used where fuel tanks are linear like square, rectangle or circular tanks.
In the contact type sensors, contact pressure variation between spring contact and sensing system leads to abnormal signal or no signal from the sensor, the contact pressure on the sensing system may increase due to assembly process or sloshing effect during operation, which will lead to wear out of the sensing system. The spring contact gets damage due to sloshing effect of fluid inside the tank since spring contact is flimsy part with spring back property. Isolation layer is formed between the sensing system and contact material due to adulterated fluid or chemical reaction between the fluid and sensing system.

WO1988001046 discloses a liquid level sensing system for use with a closed container having a varying level of liquid comprising float means within the container movable in response to variations in the level of liquid within the container, rotatably magnetic field means within the container connected to the float means so as to be at least partially rotated upon movement of the float means, stationary magnetic field sensing means outside the container for detecting variations in the position of the magnetic field caused by the partial rotation of the magnetic field of the rotatable magnetic means.

7356/DELNP/2011 discloses a liquid level detection device comprising: a float arm which is provided with a float moved by following the displacement of a liquid level; a magnet moved in association with the movement of the float arm; and a detection element for detecting a change of magnetism of the magnet.

DE10142618 discloses a tank level indicator for generation of an electrical signal corresponding to the level of fluid in a container, based on a pivoting float arm and a sensor unit for measuring the pivot position of the float arm relative to the container. The sensor measures the arm position in a contact free manner. The sensor arrangement is based on a magnet for generation of a magnetic field and a magnetic field sensitive element for measuring the change in the magnetic field caused by the pivoting of the float arm.

US6976394 discloses a level transmitter for liquid containers, comprising a housing in which a contactless sensor is arranged which is connected with an evaluating unit and operatively connected with a magnet that moves relative to the sensor when a float arranged at a first end of a lever moves so that the change of the magnetic field acting upon the sensor is transformed into an electric signal so that an output signal corresponding to the level of the liquid in the container is obtainable by the evaluating means. However, the PCB is not isolated from the direct fluid contact hence isolation layer can be formed between the level transmitter and contact material due to adulterated fluid or chemical reaction between fluid and the level transmitter.

Accordingly, there exists a need for a Hall Effect level sensing device with double magnets, which overcomes the constraints / issues faced in the contact type level sensor and uses of advantages in non-contact type level sensor. Non-contact sensing solution for the non-linear tanks are required to overcome the above issues and Hall Effect based sensor is the solution.

OBJECTS OF INVENTION
One or more of the problems of the conventional prior art may be overcome by various embodiments of the present invention.

Accordingly, it is the primary object of the present invention to provide Hall Effect level sensing device with double magnets provided with Hall Effect sensing element which is programmable type or pre-programmed type for sensing liquid level present in a container.

It is another object of the present invention to provide Hall Effect level sensing device with double magnets, which overcomes the constraints / issues faced in the contact type level sensor and uses advantages in non-contact type level sensor.

It is another object of the present invention to provide Hall Effect level sensing device with double magnets, which eliminates isolation layer formation between the sensing device and contact material due to adulterated fluid or chemical reaction between fluid and the sensing device.

SUMMARY OF INVENTION
Thus according to the basic aspect of the present invention there is provided a Hall Effect level sensing device, comprising:
flange with housing including metal pivot insert molded, said housing houses sensing element, Printed Circuit Board (PCB) and container;
lever arm; and
float,
wherein the sensing element is located in pre-defined position in the PCB within the housing,
wherein the container houses at least two magnets,
wherein the magnets are encapsulated opposite to each other with opposite poles facing each other within slots located in a pre-defined location of the container,
wherein one end of the lever arm is connected with the float and pivot point of the lever arm is attached to the container through a holder or to the holder and container which are formed as a single part, and
wherein the pivot point of the lever arm and the container moves circularly according to the movement of the float based on the level of fluid inside the tank.

It is another aspect of the present invention, wherein the PCB is fixed within the housing and covered with epoxy solution to isolate from direct fluid contact.

It is another aspect of the present invention, wherein an insulating plate is positioned in between the container and PCB.

It is another aspect of the present invention, wherein one side of the holder is provided with shaft for connecting to the pivot point and other side of the holder is provided with one or more protrusions to hold the lever arm.

It is another aspect of the present invention, wherein the pivot point of the lever arm swings radially while the float moves up or down based on the level of fluid inside a tank.

It is another aspect of the present invention, wherein the container moves circularly around the sensing element on the PCB to create change in magnetic flux on the sensing element.

It is another aspect of the present invention, wherein the sensing element converts the change in the magnetic flux on the sensing element into a linear voltage signal or container is fitted as holder.

It is another aspect of the present invention, wherein the output from the sensing element is fed to a connecting terminal through the protrusion in the flange for interfacing with cluster/ECU or to control other applications.

It is another aspect of the present invention, wherein the output from the sensing element is fed as input to an additional electronic circuitry for converting said output from the sensing element into forms of outputs as per requirement.

It is another aspect of the present invention, wherein the sensing element is a Hall Effect sensing element.

BRIEF DESCRIPTION OF THE DRAWINGS:
Figure 1: illustrates Hall Effect level sensing device with double magnets according to the present invention.
Figure 2: illustrates exploded view of the Hall Effect level sensing device with double magnets according to the present invention.

Referring to Figures 1 and 2, the Hall Effect level sensing device comprises of flange [1] with housing [2], said housing [2] houses sensing element [8], Printed Circuit Board (PCB) [9] and container [6]; lever arm [3]; and float [4]. The container [6] houses at least two magnets [7], said magnets [7] are encapsulated opposite to each other with opposite poles facing each other within slots located in a pre-defined location of the container [6]. The PCB [9] is fixed within the housing [2] and covered with sealant to isolate from the direct fluid contact, thereby eliminating formation of isolation layer formation between the Hall Effect level sensing device and contact material due to adulterated fluid or chemical reaction between fluid and the Hall Effect level sensing device. The sealant includes plastic or epoxy solutions. The sensing element [8] is located in pre-defined position in the PCB [9] within the housing [2]. An insulating plate [11] is positioned in between the container [6] and PCB [9].

One end of the lever arm [3] is connected with the float [4] and pivot point [10] of the lever arm [3] is attached to the container [6] through a holder [3a] as shown in Figure 2. In one of the embodiments the holder and container are formed as a single part. One side of the holder [3a] is provided with shaft for connecting to the pivot point [10] and other side of the holder [3a] is provided with one or more protrusions to hold the lever arm [3]. The holder [3a] is molded with metal part to avoid wear and tear. The pivot point [10] of the lever arm [3] swings radially while the float [4] moves up or down based on the level of fluid inside a tank. The pivot point [10] of the lever arm [3] and the container [6] moves circularly according to the movement of the float [4] based on the level of fluid inside the tank. The container [6] moves circularly around the sensing element [8] on the PCB [9] to create change in magnetic flux on the sensing element [8]. The container [6] is preferably circular in shape.

The sensing element [8] converts the change in the magnetic flux on the sensing element [8] into a linear voltage signal. The output from the sensing element [8] is fed to a connecting terminal [5] through the protrusion in the flange [1] as shown in Figure 2 for interfacing with cluster/ECU or to control other applications. Optionally, the output from the sensing element [8] is fed as input to an additional electronic circuitry for converting said output from the sensing element [8] into forms of outputs as per requirement such as voltage, current, resistance, CAN signals, RS232 signals, RS485 signals etc. The sensing element [1] is a Hall Effect sensing element. It should be noted that the dimensions of the housing [2] of the Hall Effect level sensing device and specification of the PCB [9] depends on vehicle application.

The advantages of the present invention are as follows:
• Suitable to sense the level of fluid in small, medium and complex profile tanks.
• Suitable to sense the level of any type of fluids such as conducting mediums, dark mediums, high viscous mediums etc.
,CLAIMS:WE CLAIM:
1. A Hall Effect level sensing device, comprising:
flange [1] with housing [2] including metal pivot insert molded, said housing [2] houses sensing element [8], Printed Circuit Board (PCB) [9] and container [6];
lever arm [3]; and
float [4],
wherein the sensing element [8] is located in pre-defined position in the PCB [9] within the housing [2],
wherein the container [6] houses at least two magnets [7],
wherein the magnets [7] are encapsulated opposite to each other with opposite poles facing each other within slots located in a pre-defined location of the container [6],
wherein one end of the lever arm [3] is connected with the float [4] and pivot point [10] of the lever arm [3] is attached to the container [6] through a holder [3a] or to the holder and container which are formed as a single part, and
wherein the pivot point [10] of the lever arm [3] and the container [6] moves circularly according to the movement of the float [4] based on the level of fluid inside the tank.

2. The Hall Effect level sensing device as claimed in claim 1, wherein the PCB [9] is fixed within the housing [2] and covered with epoxy solution to isolate from direct fluid contact.

3. The Hall Effect level sensing device as claimed in claim 1, wherein an insulating plate [11] is positioned in between the container [6] and PCB [9].
4. The Hall Effect level sensing device as claimed in claim 1, wherein one side of the holder [3a] is provided with shaft for connecting to the pivot point [10] and other side of the holder [3a] is provided with one or more protrusions to hold the lever arm [3].

5. The Hall Effect level sensing device as claimed in claim 1, wherein the pivot point [10] of the lever arm [3] swings radially while the float [4] moves up or down based on the level of fluid inside a tank.

6. The Hall Effect level sensing device as claimed in claim 1, wherein the container [6] moves circularly around the sensing element [8] on the PCB [9] to create change in magnetic flux on the sensing element [8].

7. The Hall Effect level sensing device as claimed in claim 6, wherein the sensing element [8] converts the change in the magnetic flux on the sensing element [8] into a linear voltage signal.

8. The Hall Effect level sensing device as claimed in claim 7, wherein the output from the sensing element [8] is fed to a connecting terminal [5] through the protrusion in the flange [1] for interfacing with cluster/ECU or to control other applications.

9. The Hall Effect level sensing device as claimed in claim 7, wherein the output from the sensing element [8] is fed as input to an additional electronic circuitry for converting said output from the sensing element [8] into forms of outputs as per requirement.

10. The Hall Effect level sensing device as claimed in claim 1, wherein the sensing element [1] is a Hall Effect sensing element.