Claims:CLAIMS:
What is claimed is:
1. A pressure switch for detecting pressure levels of a system, the pressure switch comprises:
a first housing comprising:
a face seal for preventing external leakage getting in to the pressure switch and vice versa;
a second housing comprising:
a diaphragm for sealing the pressure switch;
a magnet, and wherein the said magnet is a temperature resistant, with very low temperature coefficient;
a magnet holder fixed concentrically on the other side of the diaphragm and guided along the second housing, for carrying the magnet; and
a spring for holding the said magnet holder;
a spring support for holding the said spring in place; and
a third housing comprising:
an O-ring for creating a sealing at the interface between the second housing and the third housing;
a printed circuit board (PCB) assembly supported mechanically and wherein printed circuit board (PCB) assembly comprises one or more electronic components and an electrical interface for external connectivity;
a sensor for switching; and
an encapsulation, and wherein the PCB assembly and the sensor are encapsulated in the third housing for the protection from an external environment; and
wherein the diaphragm is a flexible seal which moves with respect to a applied pressure, and wherein the diaphragm moves the magnet holder, and wherein the movement of the magnet holder compresses the spring which in turn changes the magnetic flux value, and wherein the change in the magnetic flux value is sensed by the sensor and the output voltage varies accordingly and wherein the pressure is set to the desired switching pressure and the magnetic flux value is noted and the sensor is tuned for the switching, and wherein the change of switching state is programmed with defined hysteresis levels, and wherein once the sensor is tuned, the device starts switching at the set magnetic flux value which is correlated with pressure values.

2. The pressure switch according to claim 1, wherein the clogging degree of the fuel filter is obtained from the vacuum switch and an alarm signal is generated as an output, when the clogging degree exceeds a threshold value.

3. The pressure switch according to claim 1, wherein the pressure switch is fastened with a thread provided on the front housing with a face seal to ensure external leak proof with application of the pressure.

4. The pressure switch according to claim 1, wherein the diaphragm pushes the magnet holder upon application of the external pressure, and wherein the movement of the magnet holder compresses the spring which in turn changes the position of the magnet from the sensor, and wherein the change of position is sensed by sensor and the output varies accordingly.

5. The pressure switch according to claim 1, wherein the pressure is pre-set to the desired switching pressure and the magnetic flux value is noted and the sensor is tuned for switching, and wherein the change of switching state is programmed with defined hysteresis levels, and wherein the device starts switching at the set magnetic flux value which is correlated with pressure values.

6. The pressure switch according to claim 1, wherein the diaphragm isolates the media from the input orifice and the magnet side.

7. The pressure switch according to claim 1, wherein the electronics comprising the sensor and the PCB assembly are encapsulated in the third housing.

8. The pressure switch according to claim 1, wherein the sensor is a Hall Effect sensor, and wherein the Hall Effect sensor is a transducer that varies its output voltage in response to a magnetic field.

9. The pressure switch according to claim 1, wherein the pressure switch further comprises an air vent attached either to the PCB assembly or to the second housing, and wherein the said air vent is air permeable, and wherein the air vent allows only air to pass through and block the liquid medium under normal atmospheric pressure, and wherein the said air vent balances the external and internal pressure of the vacuum switch.

10. The vacuum switch according to claim 1, is adopted for detecting fuel filter clogging in the internal combustion engine.

, Description:FORM 2
The Patents Act 1970
(39 of 1970)
&
The Patent Rules 2003
COMPLETE SPECIFICATION
(See Section 10 and rule 13)

TITLE OF THE INVENTION:
DEVICE FOR DETECTING PRESSURE LEVELS IN A SYSTEM

APPLICANT:
Rotary Electronics Private Limited
No. 18, 5th Cross, 4th Stage, Industrial Town,
Rajajinagar, Bangalore 560044,
Karnataka, India.

PREAMBLE OF THE DESCRIPTION:
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED
A) TECHNICAL FIELD

[0001] The present invention generally relates to a field of pressure sensing devices and particularly relates to a device for detecting pressure levels in a system. The present invention more particularly relates to a pressure switch for detecting pressure levels precisely.

B) BACKGROUND OF THE INVENTION

[0002] The purpose of the fuel filter is to protect the injection system in internal combustion engine. Incidentally, fuel includes foreign matters, for example, water, dust, and solid undesirable materials such as rust. These foreign matters or impurities need to be removed or filtered. Fuel filters eliminate impurities present in the fuel.

[0003] Fuel filters need to be maintained at regular intervals. This is usually a case of simply disconnecting the filter from the fuel line and replacing it with a new one; although some specially designed filters can be cleaned and reused many times. If a filter is not replaced regularly it may become clogged with contaminants and cause a restriction in the fuel flow, causing an appreciable drop in engine performance as the engine struggles to draw enough fuel to continue running normally. Hence, there exists a need for a system and apparatus for detecting clogging of the fuel filter and time to replace the clogged fuel filer to ensure proper functioning of the internal combustion engine.

[0004] Various fuel filter clogging detection devices are proposed in the art, which are mainly mechanical in nature. In mechanical clogging detectors, upon detecting clogging in the fuel filter, the clogging detectors switches from one state to another pre-determined state and intimate the operator by an alarm or a hazardous light. Theses mechanical fuel filters clogging detectors are more prone to external tolerances; each component in the clogging detectors does not behave the same. There will be some compensation required. Further, the variation between the said mechanical clogging detectors can be upto 1 bar. Hence, in mechanical clogging detectors, switching will not be precise.

[0005] In view of the foregoing, there is a need to provide an efficient device for precisely detecting clogging of fuel filter in internal combustion engine. There is also a need to provide an electro-mechanical switch for precisely detecting and switching clogging of fuel filter in a diesel powered internal combustion engine. Further, there is also a need to provide a programmable pressure switch for detecting clogging of fuel filter and alarming an operator of a vehicle.

[0006] The above mentioned shortcomings, disadvantages and problems are addressed herein and which will be understood by reading and studying the following specification.

C) OBJECT OF THE INVENTION

[0007] The primary object of the present invention is to provide a pressure switch for detecting pressure levels of a system.

[0008] Another object of the present invention is to provide a pressure switch for detecting clogging of fuel filter in a diesel powered internal combustion engine.

[0009] Yet another object of the present invention is to provide a pressure switch for precisely detecting clogging of fuel filter and alarming the operator of the vehicle.

[0010] Yet another object of the present invention is to provide a programmable pressure switch, wherein switching values are accurately set.

[0011] Yet another object of the present invention is to provide a pressure switch with a programmable sensor, wherein mechanical errors are compensated by a programmable sensor.

[0012] These and other objects and advantages of the present invention will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings.

D) SUMMARY OF THE INVENTION

[0013] The various embodiments of the present invention provide a pressure switch for detecting pressure levels of a system. Further, the present invention provide a pressure switch for detecting clogging of fuel filter in diesel powered internal combustion engine. The pressure switch comprises a first housing, a second housing and a third housing. The first housing of the pressure switch comprises a face seal for preventing external leakage getting in to the pressure switch and vice versa. The pressure switch is fastened with a fastening means such as but not limited to a thread provided on the first housing with the face seal to ensure external leak proof with the application of the pressure.

[0014] According to an embodiment of the present invention, the second housing of the pressure switch comprises a diaphragm for sealing the pressure switch, a temperature resistant magnet with very low temperature coefficient, a magnet holder for carrying the magnet, a spring for holding the said magnet holder attached to the diaphragm and a spring support for holding/supporting the said spring in place.

[0015] According to an embodiment of the present invention, the third housing of the pressure switch comprises an O-ring for creating a sealing at the interface between the second housing and the third housing, a printed circuit board (PCB) assembly which is supported mechanically and the said PCB assembly comprises one or more electronic components and an electrical interface for external connectivity, a sensor for switching and an encapsulation. The PCB assembly and the sensor are encapsulated in the third housing for the protection from an external environment.

[0016] According to an embodiment of the present invention, the diaphragm is a flexible seal which moves with respect to the applied pressure. The diaphragm moves the magnet holder, and the movement of the magnet holder compresses the said spring, which in-turn changes the magnetic flux value of the magnet. The change in the magnetic flux value is sensed by the sensor and the output voltage varies accordingly. The pressure is set to the desired switching pressure and the magnetic flux value is noted and the sensor is tuned accordingly. Further, the change of switching state is programmed with a defined hysteresis levels, and once the sensor is tuned, the device (pressure switch) starts switching at the set magnetic flux value which is correlated with the pressure values.

[0017] According to an embodiment of the present invention, the clogging degree of the fuel filter is obtained through the pressure switch and an alarm signal is generated as an output to an operator, when the clogging degree exceeds a threshold value.

[0018] According to an embodiment of the present invention, the diaphragm pushes the magnet holder upon application of the external pressure, and the movement of the magnet holder compresses the spring which in turn changes the position of the magnet from the sensor. The change of position is sensed by sensor and the output varies accordingly.

[0019] According to an embodiment of the present invention, the pressure is pre-set to the desired switching pressure and the magnetic flux value is noted and the sensor is tuned for switching. The change of switching state is programmed with defined hysteresis levels, and the said pressure switch starts switching at the set magnetic flux value which is correlated with pressure values.

[0020] According to an embodiment of the present invention, the diaphragm isolates the media from the input orifice and the magnet inside.

[0021] According to an embodiment of the present invention, the electronics comprising the sensor and the PCB assembly are encapsulated in the third housing.

[0022] According to an embodiment of the present invention, the sensor is a Hall Effect sensor. The Hall Effect sensor is a transducer that varies its output voltage in response to a magnetic field.

[0023] According to an embodiment of the present invention, the pressure switch further comprises an air vent attached either to the PCB assembly or to the second housing. The said air vent is air permeable, allowing only air to pass through and block the liquid medium under normal atmospheric pressure. The said air vent balances the external and internal pressure of the vacuum switch.

[0024] These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating the preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.

E) BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The other objects, features and advantages will occur to those skilled in the art from the following description of the preferred embodiment and the accompanying drawings in which:

[0026] FIG. 1 illustrates a block diagram of a system for detecting clogging of fuel filter in diesel powered internal combustion engine, according to an embodiment of the present invention.

[0027] FIG. 2 illustrates a side view of the pressure switch for precisely detecting pressure levels of a system, according to an embodiment of the present invention.

[0028] FIG. 3 illustrates a cross-sectioned view of the pressure switch for precisely detecting pressure levels of a system, according to an embodiment of the present invention.

[0029] FIG. 4 illustrates a front side view of the pressure switch for precisely detecting pressure levels of a system, according to an embodiment of the present invention.

[0030] FIG. 5 is an exploded view of the pressure switch illustrating mechanical and electronic components adopted for precisely detecting clogging of fuel filter in a diesel powered internal combustion engine, according to an embodiment of the present invention.

[0031] Although the specific features of the present invention are shown in some drawings and not in others. This is done for convenience only as each feature may be combined with any or all of the other features in accordance with the present invention.

F) DETAILED DESCRIPTION OF THE INVENTION

[0032] In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which the specific embodiments that may be practiced is shown by way of illustration. These embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments and it is to be understood that the logical, mechanical and other changes may be made without departing from the scope of the embodiments. The following detailed description is therefore not to be taken in a limiting sense.

[0033] The various embodiments of the present invention provide a pressure switch for detecting pressure levels of a system. Further, the present invention provide a pressure switch for detecting clogging of fuel filter in diesel powered internal combustion engine. The pressure switch comprises a first housing, a second housing and a third housing. The first housing of the pressure switch comprises a face seal for preventing external leakage getting in to the pressure switch and vice versa. The pressure switch is fastened with a fastening means such as but not limited to a thread provided on the first housing with the face seal to ensure external leak proof with the application of the pressure. The diaphragm moves the magnet holder upon application of external pressure, and the movement of the magnet holder compresses the said spring, which in-turn changes the magnetic flux value of the magnet. The change in the magnetic flux value is sensed by the sensor and the output voltage varies accordingly. The pressure is set to the desired switching pressure and the magnetic flux value is noted and the sensor is tuned accordingly. The change of switching state is programmed with defined hysteresis levels. Once the sensor is tuned, the device starts switching at the set magnetic flux value which is correlated with pressure values. Further, the diaphragm isolates the media from the input orifice and the magnet inside. The electronics are encapsulated in a separate housing.

[0034] FIG. 1 illustrates a block diagram of a system for detecting clogging of fuel filter in diesel powered internal combustion engine, according to an embodiment of the present invention. The system comprises a diesel fuel filter 102 for filtering foreign matters or contaminants such as but not limited to water, dust, and solid undesirable materials like rust from the diesel fuel, an Electronic Control Unit (ECU) 103 for controlling a series of actuators on an internal combustion engine to ensure optimal engine performance and a pressure switch 101 for precisely detecting clogging of fuel filter.

[0035] According to an embodiment of the present invention, the said diesel fuel filter 102 is fixed in a fuel line, for screening out dirt and rust particles from the fuel, normally made into cartridges containing a filter paper. The said diesel fuel filter 102 comprises a fuel inlet 104 for receiving fuel from a fuel tank and a fuel outlet 105 for dispensing filtered dust free fuel from the diesel fuel filter 102 to the fuel injection system of the internal combustion engine. The said pressure switch 101 is fixed at the fuel outlet 105 of the diesel fuel filter 102 for measuring the outlet pressure of the fuel filter as shown in FIG. 1.

[0036] FIG. 2 illustrates a side view of the pressure switch for precisely detecting pressure levels of a system, according to an embodiment of the present invention. The said pressure switch 101 comprises a first housing 201 including a plurality of mechanical components for measuring fuel pressure; a second housing 202 including a magnet for sensing the pressure value; a third housing 203 including a sensor Integrated Circuit; and a PCB assembly for sensing magnetic flux. The said pressure switch 101 further comprises a wiring harness 204 for transferring measured pressure value; and a connector 205 for connecting the said pressure switch 101 to the ECU 103.

[0037] FIG. 3 illustrates a cross-sectioned view of the pressure switch for precisely detecting pressure levels of a system, according to an embodiment of the present invention. The pressure switch 101 comprises a first housing, a second housing and a third housing. The first housing 201 of the pressure switch 101 comprises a face seal for preventing external leakage or dust or liquids getting in to the pressure switch 101 and vice versa. The second housing 202 of the pressure switch 101 comprises a diaphragm 301 for sealing the pressure switch 101, a magnet holder 302 fixed concentrically on the other side of the diaphragm 301 and guided along the second housing, for carrying a magnet 306, and wherein the said magnet 306 is a temperature resistant and very low temperature coefficient magnet; a spring 303 for holding the said magnet holder 302 attached to the diaphragm 301; and a spring support 304 for holding the said spring 303 in place. Further, the third housing 203 of the pressure switch 101 comprises an O-ring 309 for creating a sealing at the interface (between the second housing 202 and third housing 203); a printed circuit board (PCB) assembly 308, which is mechanically supported and the said PCB assembly comprises one or more electronic components and an electrical interface for external connectivity using conductive tracks, pads and other features etched from copper sheets laminated onto a non-conductive substrate; a sensor 307 for switching; and an encapsulation 305. The entire rear unit is housed in the third housing 203 and is encapsulated with the PCB assembly 308 for the protection from external environment.

[0038] According to an embodiment of the present invention, the diaphragm 301 is a flexible seal which moves with respect to the applied external pressure. The diaphragm 301 moves the magnet holder 302 upon application of external pressure, and the movement of the magnet holder 302 compresses the said spring 303, which in-turn changes the magnetic flux value of the magnet 306. The change in the magnetic flux value is sensed by the sensor 303 and the output voltage varies accordingly. The pressure is set to the desired switching pressure and the magnetic flux value is noted and the sensor 303 is tuned accordingly. The mechanical movement of the diaphragm 301 is converted into a magnetic flux value, which in-turn is converted into an electrical signal by the sensor 307. The pressure is set to the desired switching pressure and the magnetic flux value is noted, and the sensor 307 is tuned for the switching. The change of switching state is programmed with a defined hysteresis levels, and once the sensor is tuned, the device (pressure switch 101) starts switching at the set magnetic flux value which is correlated with the pressure values.

[0039] According to an embodiment of the present invention, when the diaphragm 301 moves to and fro, the magnet 306 also moves within the second housing 202. The magnet 306 moves along with the diaphragm 301 which goes through the spring 303. Further, with the differential pressure, the magnet 306 movement changes, so this will change the magnetic flux and the flux value is sensed by the sensor 307, which is housed on the PCB assembly 308.

[0040] FIG. 4 illustrates a front side view of the pressure switch for precisely detecting pressure levels of a system, according to an embodiment of the present invention. The pressure switch 101 comprises a fastening means such as but not limited to a thread provided on the first housing as shown in FIG. 4. The pressure switch 101 is fastened with the thread provided on the front housing with a face seal to ensure external leak proof and vice versa with the application of fuel pressure.

FIG. 5 is an exploded view of the pressure switch illustrating mechanical and electronic components adopted for precisely detecting pressure levels of a system, according to an embodiment of the present invention. The pressure switch 101 comprises a face seal 501 housed inside the first housing 201 for preventing external leakage and vice versa; a diaphragm 301 for sealing the system (pressure switch 101), a magnet holder 302 for carrying a magnet 306, a spring 303 for holding the said magnet holder 302 attached to the diaphragm 301, a spring support 304 for holding the said spring 303 in place, which are housed inside the second housing 202; an O-ring 309 for creating a sealing at the interface, a printed circuit board (PCB) assembly 308 mechanically supported for electrically connecting electronic components, and an encapsulation 305. The entire rear unit is housed in the third housing 203 and is encapsulated with the PCB assembly 308 for the protection from external environment. The said pressure switch 101 further comprises a wiring harness 204 for transferring measured pressure value; and a connector 205 for connecting the said pressure switch 101 to the ECU 103.

[0041] According to an embodiment of the present invention, the pressure switch 101 further comprises an air vent 501 attached either to the PCB assembly 308 or to the second housing. The said air vent 501 is an air permeable, allowing only air to pass through and blocking the liquid medium under normal atmospheric pressure. The said air vent 501 balances the external and internal pressure of the pressure switch 101.

[0042] According to an embodiment of the present invention, the O-ring 309, also known as a packing, or a toric joint, is a mechanical gasket in the shape of a torus; it is a loop of elastomer with a round cross-section, designed to be seated in a groove and compressed during assembly between two or more parts, creating a seal at the interface between the second housing 202 and the third housing 203.

[0043] According to an embodiment of the present invention, the sensor 307 is a Hall Effect sensor, and wherein the Hall Effect sensor is a transducer that varies its output voltage in response to a magnetic field. The Hall Effect sensors are used for: such as but not limited to proximity switching, positioning, speed detection, and current sensing applications.

G) ADVANTAGES OF THE INVENTION

[0044] The various embodiments of the present invention provide a pressure switch for precisely detecting pressure levels of a system. This will enhance the life of the diesel fuel filter. With increased life of diesel fuel filter, the end user has a much lower maintenance cost.

[0045] The pressure switch of the present invention protects the fuel injection pump from damage that may be caused due to usage of clogged filters beyond life.

[0046] The pressure switch of the present invention is of Hall Effect based electrically programmable type, and flexible enough to adapt in different requirements/environments. With the said programmable pressure switch, the mechanical errors are compensated.

[0047] The pressure switch of the present invention provides two state programmable features, which helps in accurate switching and further provides low hysteresis.

[0048] The pressure switch of the present invention gives direct analog output.

[0049] The electronics of the said pressure switch are totally isolated from the working media i.e. mechanics, ensuring more safety of the electronics.

[0050] The said programmable advanced Hall Effect switch/latch IC (pressure switch) enables end-of-line (EOL) calibration to reduce mechanical tolerances assuring reliable and accurate switching thresholds.

[0051] The said end-of-line (EOL) programmable feature ensures a very good First Time Quality (FTQ).

[0052] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the appended claims.

[0053] Although the embodiments herein are described with various specific embodiments, it will be obvious for a person skilled in the art to practice the invention with modifications. However, all such modifications are deemed to be within the scope of the claims.

[0054] It is also to be understood that the following claims are intended to cover all of the generic and specific features of the embodiments described herein and all the statements of the scope of the embodiments which as a matter of language might be said to fall there between.