FIELD OF THE INVENTION
Fuel level sensor finds application for sensing the level of fuel in a fuel tank. The fuel level sensor comprises grooved aluminum tube, a float (80) with magnet (81) flange (40) with integral connector (60), PCB assembly (72) with Reed switches (71) and Resistor (70), Bottom cover. The float cavity (55) is in the grooved profile of Aluminum tube, which is rigidly fixed to the flange (40). The PCB assembly (72) along with reed switches (71) and resistor (70) is connected to the terminals in the integral connector (60) in the flange (40). The float (80) moves up and down based on the fuel level, which in turn activates a particular reed switch (71) by magnetic effect between the magnet (81) in the float (80) and the terminals in the reed switch (71). Hence the circuit closes up to the particular reed switch (71). The resistance value against the reed switch (71) is received as the output from the Fuel gauge.
BACKGROUND OF THE INVENTION
Numerous design constraints are imposed upon fuel level sensors. For instance, fuel level sensors must be capable of withstanding corrosive environments, as the sensor is at least partially submerged in fuel and various types of fuel additives throughout its operational life. Also, the sensor is frequently subjected to extreme vibration and shock, elements that are intensified in recreational vehicle applications. Traditionally, two primary fuel level sensor designs have been employed to address the aforementioned needs. The first entails a purely mechanical design while the second utilizes magnetically activated reed-switches.
The purely mechanical fuel level sensor generally includes a float, a spiral strip of metal, and a fuel gauge. In operation, the float moves according to the fuel level in a vertical direction along the spiral strip of metal, which is attached to an indication needle of the fuel gauge. As the fuel level rises and lowers, the float causes the strip of metal to turn, thus moving the indication needle of the fuel gauge and informing the operator of the current fuel level.
The reed-switch type fuel level sensor, on the other hand, typically includes an elongated circuit board containing a series of reed-switches and resistors and is encapsulated by a

protective housing that is partially surrounded by a float having a magnetic component. The encapsulated circuit board is generally aligned in a vertical orientation, such that a change in the fuel level causes the float to move up and down along the circuit. As the magnet carrying float vertically moves along the circuit, reed-switches located at various vertical positions are activated and deactivated. Interspersed between these reed-switches are resistors, all of which are connected in series and help form a complete current path. When the fuel level is at a half of a tank, for example, the magnet carried by the float activates a reed-switch located at an equivalent vertical position. Activating that reed-switch causes the resistors located below the switch to be shorted. Therefore, assuming a constant voltage source, the amount of electrical current through the circuit is related to the number of series connected resistors that it flows through, and thus is related to the fuel level. Numerous fuel level sensors employ a magnet carrying float and reed-switches.
Thus, it would be advantageous to provide a fuel level sensor that utilized series connected resistors and magnetically activated switches in order to provide an accurate, compact, and rugged fuel level sensor.
OBJECTS OF INVENTION
The principle objective of the present invention is to develop an integrated fluid level
sensor.
Yet another object of the present invention is to develop a method to detect fluid level.
Still another object of the present invention is to develop a method of assembling
integrated fluid level sensor
STATEMENT OF INVENTION
Accordingly the present invention provides an integrated fluid level sensor, comprising: a guide body (10) with a float cavity (55) to guide a float during variation of the fluid level, with reed switches (71) and resistors (70) PCB assembly (72) placed in a compartment of the guide body (10) for float (80) level indication, and a flange (40) with the guide body (10) mounted to it, wherein the flange (40) comprising an integrated valve assembly (41) to regulate pressure built inside a fluid tank, and a gauge driver PCB (61) connected to the PCB assembly (72) to indicate fluid level; the present invention also provides a

method to detect fluid level comprises steps of: regulating the pressure built inside a tank with an integrated valve (41) inside a flange (40), guiding a float (80) carrying a magnet (81) along the guide body (10) by mounting a guide body (10) onto the flange (40) with float cavity (55), indicating the level of a float (80) by placing reed switch (71) and resistor PCB assembly (72) in the guide body (10), and measuring the fluid level by placing a gauge driver PCB (61) inside the flange (40) which is connected to the reed switch (71) and resistor PCB. the present invention also provides a method of assembling a integrated fluid level sensor comprises, placing an integrated valve assembly (41) inside a flange (40) to regulate the pressure built inside a fluid tank, placing a gauge driver PCB (61) inside a flange (40) to indicate level of a float (80) mounted on a float guide through a top grommet (90), mounting a guide body (10) to the flange (40), wherein guide body (10) has a pickup cavity, a return cavity for the fluid to flow and float cavity (55), placing a reed switch (71) and resistor PCB assembly (72) inside the PCB compartment, and fixing grommet (91) to the PCB compartment and bottom cover to the guide body (10).
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 shows front perspective view of the Fluid level Sensor
Figure 2 shows block drawing of the instant invention with different parts of it
Figure 3 shows a reed switch (71)
Figure 4 Shows perspective view of Valve for robust holding of Housing with the Flange
(40).
Figure 5 Shows perspective view of Housing of the Fluid level Sensor.
Figure 6 Shows view of the Flange (40) with Gauge drive PCB connector of the Fluid level Sensor.
Figure 7 Shows perspective assembly view of PCB.
Figure 8 Shows perspective view of the Float Assembly of the Fluid level Sensor.
Figure 9 a Shows perspective view of top grommet (90).
Figure 9 b Shows perspective view of bottom grommet (91).
Figure 10 Shows front perspective view of the Valve assembly (41).

DESCRIPTION OF THE INVENTION
The primary embodiment of the invention is an integrated fluid level sensor, comprising: a guide body (10) with a float cavity (55) to guide a float (80) during variation of the fluid level, with reed switches (71) and resistors (70) PCB assembly (72) placed in a compartment of the guide body (10) for float level indication, a flange (40) with the guide body (10) mounted to it, wherein the flange (40) comprising an integrated valve assembly (41) to regulate pressure built inside a fluid tank, and a gauge driver PCB (61) connected to the PCB assembly (72) to indicate fluid level.
In yet another embodiment, the guide body (10) provides for point contact (82) float cavity (55).
In still another embodiment, the float cavity (55) provides for atleast three point contacts (82) with the float (80).
In still another embodiment, the guide body (10) comprises pickup cavity, return cavity for the fluid to flow.
In still another embodiment, the cavities (50, 52) are provided with filters to restrict foreign materials.
In still another embodiment, the integrated valve assembly (41) comprises atleast one port for passing atmospheric pressure.
In still another embodiment, the valve assembly (41) comprises a bush for releasing of atmospheric pressure.
In still another embodiment, the valve assembly (41) comprises a spring compressions to intake atmospheric pressure.
In still another embodiment, a magnet (81) is mounted onto the float (80) to activate the reed switches (71) to indicate the float (80) position.
In still another embodiment, the guide body (10) is provided with grommet (91) at the bottom to restrict fluid entry into the PCB assembly (72).
In still another embodiment, a grommet (90) at the top end of the guide body (10) comprises a hole to pass wires from the PCB assembly (72) to the gauge driver PCB (61).

In still another embodiment, the guide body (10) is provided with a bottom cover to restrict float (80) movement within the float cavity (55) with a provision for fluid to flow into the cavities (50, 52).
Another embodiment of the present invention is a method to detect fluid level comprises steps of: regulating the pressure built inside a tank with an integrated valve (41) inside a flange (40), guiding a float (80) carrying a magnet (81) along the guide body (10) by mounting a guide body (10) onto the flange (40) with float cavity (55), indicating the level of a float (80) by placing reed switch (71) and resistor (70) PCB assembly (72) in the guide body (10), and measuring the fluid level by placing a gauge driver PCB (61) inside the flange (40) which is connected to the reed switch (71) and resistor (70) PCB.
In yet another embodiment is providing cavities (50, 52) in the guide body (10) for fluid movement.
Another embodiment of the present invention is a method of assembling a integrated fluid level sensor comprises, placing an integrated valve assembly (41) inside a flange (40) to regulate the pressure built inside a fluid tank, placing a gauge driver PCB (61) inside a flange (40) to indicate level of a float (80) mounted on a float (80) guide through a top grommet (90), mounting a guide body (10) to the flange (40), wherein guide body (10) has a pickup cavity, a return cavity for the fluid to flow and float cavity (55), placing a reed switch (71) and resistor (70) PCB assembly (72) inside the PCB compartment, and fixing grommet to the PCB compartment and bottom cover to the guide body (10).
In yet another embodiment the gauge driver PCB (61) is connected to the resistor (70) PCB assembly (72) for indicating the fluid level.
Conventional sensing devices for use in sensing the liquid level in fuel tanks include a pickup tube and a return tube positioned adjacent to a float (80).
This invention relates to tubular fuel level sensors for use with vehicle fuel tanks such as Car, LCV, HCV, off road vehicle, snowmobiles, etc... An indicating instrument will be used in conjunction with the fuel sensor to read the fuel level in the tank.
Fluid level sensor finds application for sensing the level of fluid in a fluid tank. A fluid level sensor comprises of grooved aluminum tube, a float (80) with magnet (81), flange

(40) with connector (60), PCB assembly (72) with Reed switches (71) and Resistors (70), Gauge driver PCB (61), Bottom cover. The float (80) guides in the grooved profile of Aluminum tube, which is rigidly fixed to the flange (40). The PCB assembly (72) along with reed switches (71) and resistors (70) is connected to the Gauge driver PCB (61). The Gauge driver PCB (61) is inserted in the flange (40). The float (80) moves up and down based on the fluid level, which in turn activates a particular reed switch (71) by magnetic effect between the magnet (81) in the float (80) and the terminals in the reed switch (71). Hence the circuit closes up to the particular reed switch (71). The resistance value against the reed switch (71) is received as the output from the Fluid gauge.
The output resistance of the reed switch (71) is taken as input by the gauge driver PCB (61) in the flange (40), which gives the fluid level.
In accordance with the invention, a liquid level sensor consists an integral tube includes therein a pickup tube, a return tube and a grooved path for the movement of the float (80). A sensing board known as PCB ASSEMBLY (72) is positioned within cavity in the housing.
The resistor (70) in the PCB reads the fluid level in the tank after the reed switch (71) gets activated. The activation of reed switch (71) is based on the principle of activating a reed switch (71) with another magnet (81) will allow closed operation. The system is also provided with an improved liquid level sensing device that is not subjected to wild fluctuations in the liquid level due to movement of the vehicle in rough terrain. When the sensing device is installed within the tank, the sensing device is not likely to be damaged by contact (82) with a tank opening
Advantages of Reed switch (71)
• Reed switches (71) are hermetically sealed in glass environment, free from contamination, and are safe to use in harsh industrial and explosive environments.
• Reed switches (71) are immune to electrostatic discharge (ESD) and do not require any external ESD protection circuits.
• The isolation resistance between the contacts (82) is as high as 1015 ohms, and contact resistance is as low as 50 milliohms.

• Reed switches (71) can directly switch loads as low as a few microwatts without
needing external amplification circuits, to as high as 120W. Figure 2 details as listed below

S.No. PART NAME
1. FLANGE (40)
2. CONNECTOR (60)
3. ASSEMBLY VALVE (41)
4. PCB ASSEMBLY (72)
5. FLOAT (80).
6. TOP GROMMET (90)
7. BOTTOM COVER.
8. BOTTOM GROMMET (91)
9. GUIDE BODY (10)
Details of the components used in fluid level sensing
The Flange (40) is the mounting component which is used to mount all the other components. It consists of pickup tube return tube, air vent hole and holes for mounting valve assembly (41) and connector (60) assembly. In this flange (40) we mount integrated valve assembly (41) instead of separate valves. The main function of this valve (41) is to regulate the pressure, which is built inside the tank i.e. over/under vacuum pressure in tank Vs atmospheric pressure.
The Tube is the integrated profile which is designed for pickup tube, return tube, reed tube and float (80) movement passage instead of single separate tube. The new design is robust when compared to the existing design.
The guide body (10) comprises float cavity (55); cavities (50, 52) and PCB compartment. The float cavity (55) is having point's contacts (82) over its surface at 4 places to have friction free movement of the float (80). These four points will have contact (82) with the float (80) thus reducing the amount of friction, wear and tear due to surface contact (82) ofthe float (80).

The cavities (50, 52) are to use as suction and return of the fluid. The suction cavity is usually bigger in size compare to the return cavity. Having these cavities (50, 52) will have an advantage of not having separate cavities (50, 52) for suction and return of the fluid in fluid tank. This gives advantage of not have fluid leakage due to the separate holes punched for fluid suction and return. This will also eliminate the time required to punch holes and welding to have air tight in the assembly line. The compartment is the place where the PCB is inserted. Guide ribs are provided to fix the PCB in tact. This compartment is made bigger than required to place the PCB assembly (72) to reduce the weight of the guide body (10) and to reduce the material cost. The contour of the body is designed to have flat surface on one side to have pool-proofing method in the flange (40) assembly. The Flange (40) can also have a provision to allow the return and suction of the fluid to the guide body (10) cavities (50, 52). The guide body (10) is made up of Aluminium or plastic or poly acetal like Delrin based on the requirements of the flexi fluid.
The float (80) is designed to have blind cavity and not a through cavity to fix the magnet(s) (81). This is having an advantage to fix the magnet(s) in the ideal position and more rigid. The float (80) contour is designed to have points contact (82) instead of surface contact (82) with the float cavity (55) to avoid friction/wear in the floating movement. The outer circumference of the float ribs has point contact (82) with the float cavity (55) of the guide body (10). This float (80) is made out of hard rubber sponge using 14 chemical compositions bonding to have compatible with flexi fluid. The composition is varied in such a way that it suits the requirement of the flexi fluid.
Top grommet (90) is placed in between the inner flange (40) surface and PCB top surface. It acts as a stopper for the fluid level sensor PCB. Top grommet (90) has a hole in left side, which is used to take wires outside from fluid level sensor PCB to gauge driver PCB (61). It gives sealing effect, not to entry any particles into the tank. It is made up EPDM 60 (Ethylene propylene Diane monomer) rubber.
Valve assembly (41) is used to release or intake the atmospheric pressure when required i.e. from tank to atmosphere or from atmosphere to tank. The valve (41) has single inlet and outlet port, but having two passages for release and intake the atmospheric pressure.

The valve has separate bush and spring compressions for release & intake. Both the valves are integrated and placed in single housing.
Vacuum will create inside the tank during fluid suction, when the vacuum pressure exists "the limit, the flow of fluid will not be linear and also there will be chance to blast tank or any other functional problems. So, to overcome this problem, valve assembly (41) is fixed on the top of the integrated fluid level sensor. When vacuum pressure reaches 0.199 bars, bush will move downwards due to the vacuum and allows atmospheric air in to the tank from atmosphere, to break that vacuum pressure i.e. to balance.
Atmospheric pressure will create inside the tank due to opening of valve 1 (i.e. Bush 1). Bubbles or fluid flow restriction will be there due to excess of atmospheric pressure instead of atmospheric air. To overcome this problem, integrated fluid level sensor needs one more valve to release this excess atmospheric pressure to atmosphere. When atmospheric pressure reaches 0.02 bar, bush will lift upwards due to pressure and releases the atmospheric air, from tank to atmosphere.
Integrated fluid level sensor has two PCB's, one is inserted vertically inside the integrated tube and other one is inserted on the top of flange (40) (Slot is provided in the flange (40) to insert).
Fluid level measuring PCB or Reed switch PCB consists of reed switches (71) and resistors (70), which are used to measure the corresponding fluid level in the fluid tank. It is placed vertically inside the integrated tube. The output of this PCB is ohms or resistance, but the customer requirement is voltage or volts.
Gauge driver PCB (61) or Secondary PCB consists of electronic components, which is used to convert ohms into volts. It converts the corresponding ohms value in to volts to drive the gauge or to the EMU. Four Pin DIN standard connector is connected to gauge driver PCB (61) to take output.
The following are the advantages of the instant inventions flange (40) design over the previous flange (40) design:
1. The design is simple with no complication.
2. Easy to service and replace.

3. Easy for tool making.
4. Product making time is very short.
5. Material cost is low.
6. Single hole is provided for integrated valve assembly (41) instead of several holes.
7. Assembling and Replace of connector assembly is easy.
8. Stopper is provided to arrest connector rotation, during assembling (Customer Side)
9. This product works under IP67 (Ingress protect of water and air.)
10. Slots are provided in the flange (40) for easy assembling of driver gauge PCB (Ohms to Volts)
11. Single cavity is provided for pickup tube. Return Tube, PCB & float (80) passage instead of separate cavities (50, 52).
12. Flange (40) is made up of Plastic instead of Aluminum.
13. Easily replaced, when problem occurs in flange (40) or valve assembly (41).
The following are the advantage of the valve assembly (41) over the prior art valve assemblies or design.
1. Simple design.
2. Easy to replace.
3. Easy and less time for assembling.
4. Material cost is low.
5. Valves (to regulate the Vacuum and Atmospheric pressure inside the tank) are integrated in one assembly instead of separate assembly.
6. Valve assembly can be easily replaced, because of integrated.

We Claim:
1. An integrated fluid level sensor, comprising:
a. a guide body (10) with a float cavity (55) to guide a float (80) during variation
of the fluid level with reed switches (71) and resistors (70) PCB assembly
(72) placed in a compartment of the guide body (10) for float (80) level
indication, and
b. a flange (40) with the guide body (10) mounted to. it, wherein the flange (40)
comprising an integrated valve assembly (41) to regulate pressure built inside
a fluid tank, and a gauge driver PCB (61) connected to the PCB assembly (72)
to indicate fluid level.
2. The integrated fluid level sensor as claimed in claim 1, wherein the guide body (10) provides for point contact (82) float cavity (55).
3. The integrated fluid level sensor as claimed in claim 2, wherein the float cavity (55) provides for atleast three point contacts (82) with the float (80).
4. The fluid level sensor as claimed in claim 1, wherein the guide body (10) comprises pickup cavity, return cavity for the fluid to flow.
5. The fluid level sensor as claimed in claim 4, wherein the cavities (50, 52) are provided with filters to restrict foreign materials.
6. The integrated fluid level sensor as claimed in claim 1, wherein the integrated valve assembly (41) comprises atleast one port for passing atmospheric pressure.
7. The integrated fluid level sensor as claimed in claims 1 and 6, wherein the valve assembly (41) comprises a bush for releasing of atmospheric pressure.
8. The integrated fluid level sensor as claimed in claims 1 and 6, wherein the valve assembly (41) comprises a spring compressions to intake atmospheric pressure.

9. The integrated fluid level sensor as claimed in claim 1, wherein a magnet (81) is mounted onto the float (80) to activate the reed switches (71) to indicate the float (80) position.
10. The integrated fluid level sensor as claimed in claim 1, wherein the guide body (10) is provided with grommet (91) at the bottom to restrict fluid entry into the PCB assembly (72).
11. The integrated fluid level sensor as claimed in claim 1, wherein a grommet (90) at the top end of the guide body (10) comprises a hole to pass wires from the PCB assembly (72) to the gauge driver PCB (61).
12. The integrated fluid level sensor as claimed in claims 1 and 4, wherein the guide body (10) is provided with a bottom cover to restrict float (80) movement within the float cavity (55) with a provision for fluid to flow into the cavities (50, 52).
13. A method to detect fluid level comprises steps of:
a. regulating the pressure built inside a tank with an integrated valve inside a
flange (40),
b. guiding a float (80) carrying a magnet (81) along the guide body (10) by
mounting a guide body (10) onto the flange (40) with float cavity (55),
c. indicating the level of a float (80) by placing reed switch (71) and resistor (70)
PCB assembly (72) in the guide body (10), and
d. measuring the fluid level by placing a gauge driver PCB (61) inside the flange
(40) which is connected to the reed switch (71) and resistor (70) PCB.
14. The method as claimed in claim 13, wherein providing cavities (50, 52) in the guide body (10) for fluid movement.
15. A method of assembling a integrated fluid level sensor comprises.

a. placing an integrated valve assembly (41) inside a flange (40) to regulate the
pressure built inside a fluid tank,
b. placing a gauge driver PCB (61) inside a flange (40) to indicate level of a float
(80) mounted on a float (80) guide through a top grommet (90),
c. mounting a guide body (10) to the flange (40), wherein guide body (10) has a
pickup cavity, a return cavity for the fluid to flow and float cavity (55),
d. placing a reed switch (71) and resistor (70) PCB assembly (72) inside the PCB
compartment, and
e. fixing grommet (91) to the PCB compartment and bottom cover to the guide
body (10).
16. The integrated fluid level sensor as claimed in claim 15, wherein the gauge driver
PCB (61) is connected to the resistor (70) PCB assembly (72) for indicating the fluid
level.
17. An integrated fluid level sensor, a method to detect fluid and method of assembling
the integrated fluid level sensor as herein described in the description with examples
and substantiated along with accompanied drawings.