Patent Application
20180147512
This application claims priority under 35 U.S.C. ยง 119 to patent application number IN 201641040878 filed on Nov. 30, 2016 in India, the disclosure of which is incorporated herein by reference in its entirety.
The invention here relates to an air venting device for a filter.
Selective Catalytic Reduction system is a technology used in diesel engines to reduce NOx emissions by having chemical reaction between aqueous urea solution and exhaust gas. The hydraulic circuit of selective catalytic reduction system consists of storage tank, pump, filters, valves, hose and spraying device and aqueous urea solution as working medium. In present system, the supply module pumps the working medium to the dosing module. Before pumping the working medium, the working medium is filtered so that to ensure that the clean working medium is supplied to the dosing module. The main filter is permanently fixed or welded with carrier assembly which holds the level sensor and then the carrier assembly is fitted to the tank. During the testing process of vehicle in the assembly plant, the selective catalytic reduction system is supposed to build the required system pressure within specified time which is the threshold value to pass the general criteria for all vehicles but the system fails. This failure is dependent on various parameters.
The U.S. Pat. No. 5,951,862 discloses a filter. Here the filter comprises a filter cartridge located within a housing. Fuel flows through a filter medium of the cartridge, in use, from an outer chamber to an inner chamber. From the inner chamber, the fuel flows over and around a sedimentation baffle located within a sedimentation chamber. Fuel exits the sedimentation chamber through an outlet passage, an air collection chamber being arranged to collect air from the flow of fuel. Air exits the air collection chamber via openings.
A first embodiment of the present invention includes an air venting device for a filter. The air venting device includes a flow path, a frame, a movable element, a flexible element, and a slab. The flow path includes a first flow path end and an opposite second flow path end, and is configured to allow a fluid to flow through the air venting device. The frame is located in the second flow path and includes a first frame end and a second frame end. The movable element is located in the frame. The flexible element is located in the frame and includes a first flexible element end attached to the first frame end and a second flexible element end attached to the movable element. The slab is located in the second frame end. The movable element abuts the slab.
A further embodiment of the present invention includes a filter for a selective catalytic reduction (SCR) system. The filter includes a filter housing and an air venting device. The filter housing is configured to enable a fluid to flow from the filter. The air venting device includes a flow path, a frame, a movable element, a flexible element, and a slab. The flow path includes a first flow path end and an opposite second flow path end, and is configured to allow a fluid to flow through the air venting device. The frame is located in the second flow path and includes a first frame end and a second frame end. The movable element is located in the frame. The flexible element is located in the frame and includes a first flexible element end attached to the first frame end and a second flexible element end attached to the movable element. The slab is located in the second frame end. The movable element abuts the slab.
An exemplifying embodiment of the invention is explained in principle below with reference to the drawings. The drawings are,
In the air venting device 100, the flexible element 104 is a spring element and one end of the spring element is attached to the first end of the frame 103 and other end of the spring element is attached to the movable element 105. The movable element 105 is a structure made up of material which is compatible for the fluid. For example if the fluid is Ad blue then the compatible material for movable element 102d is HNBR i.e. hydrogenated nitrile butadiene rubber. Also the fluid disclosed as above refers to air, liquid or any other liquid variants.
In the air venting device 100, the first end 102a of the flow path 102 is adapted to have first diameter and second end 102b of the flow path 102 adapted to have second diameter. The diameters of both the first end 102a and the second end 102b of the flow path 102 are different and the diameter of the second end 102b of the flow path 102 is larger than the diameter of the first end 102a of the flow path 102 so that the frame 103 can be easily located in the second end 102b of the flow path 102.
According to an embodiment of this disclosure, in the air venting device 100, the frame 103 is locked to the second end 102b of the flow path 102 by a locking means 102c. Here the locking means 102c can be for example a snap fit lock which locks the frame 103 to the second end 102b of the flow path 102 from inside. The locking means 102c can be any means which is capable to lock the frame 103 to the second end 102b of the flow path 102 from inside. For example the locking means 102c is a screw and preferably the locking means 102c is located in between the second end 102b of the flow path 102 and the frame 103.
According to an embodiment of this disclosure, the frame 103 has at least two protrusions 102d to hold the slab 106. Here the protrusions 102d are the extensions from the frame 103 so that the slab 106 can be held easily on the extensions. Also the slab 106 is a salt slab which can be dissolved easily into the fluid.
According to an embodiment of this disclosure, the slab 106 is adapted to hold the movable element 105 when the flexible element 104 is in the compressed state. The movable element 105 is held by the slab 106. One end of the flexible element 104 is attached to the movable element 105 on one side and the second side of the movable element 105 is free and therefore held by the slab 106. Also the flexible element 104 is in the compressed state when the slab 106 is holding the movable element 105.
The flexible element 104 is adapted to expand and contract based on the movement of the movable element 105. Also as described above the slab 106 is a salt slab which can dissolve into the fluid. So when the slab 106 comes in contact with the fluid it dissolves and then the movable element 105 due to pre-tensioned force of flexible element 104, starts moving down and finally seals the first end 102a of the flow path 102.
The main aim of the air venting device in accordance with this disclosure is to vent the trapped air out from the filter 200 during final testing of the vehicle. This is a onetime process. By doing this, the selective catalytic reduction system of a vehicle will be able to build the required pressure for example 1.5 bar in a limited time which is say 120 seconds.
When the fluid is filled inside the filter 200 for the first time, the trapped air from the filter 200 starts moving upwards in the air venting device 100 via the first end 102a of the flow path 102 and as the volume of the fluid increases the trapped air is vacated from the filter 200 via air venting device 101. As the volume of the fluid increases, the fluid from filter housing 101 flows to the air venting device 100 and touches the slab 106 where the slab 106 dissolves in the fluid and the movable element 105 held by the slab 106 moves down and blocks the first end 102a of the flow path 102. One the air venting device 100 is blocked, the fluid starts flowing to the system of the vehicle. This blockage of air venting device 100 will be for the entire life time of the selective catalytic reduction system of the vehicle.
It must be understood that the embodiments explained in the above detailed description in only illustrative and does not limit the scope of this invention. The scope of this invention is limited only by the scope of the claims. Many modification and changes in the embodiments aforementioned are envisaged and are within the scope of this invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201641040878 | Nov 2016 | IN | national |
