Title of Invention	A SINGLE FLAP DUST DISPOSAL UNIT FOR WIND DUCT OF SINTER MACHINE
Abstract	A single flap dust disposal unit for wind duct of sinter machine comprising flap assembly (13), a hopper (20), plurality of sensor means (10,17) for detecting presence of materials to be removed, actuator means (11) in operative connection with the said flap assembly (13) and PLC (21) receiving inputs from the said sensor means and conveying signals to said actuator means (11).

Full Text

Field of the invention The present invention relates to a single flap dust disposal unit for wind duct of sinter machine. The invention further relates to a single flap dust disposal system comprising one or more such single flap units wherein each of the single flap unit is activated by pneumatic activation in a predetermined fashion through a PLC. The unit and the system comprising the same enables simple yet effective removal of dust from the wind duct of sinter machines. Background of the invention Sinter machines have a huge wind duct, which is connected to the suction boxes/wind boxes over which the sinter cars travel. Huge fans suck the air through the green mix charged on sinter cars. The wind boxes and wind-duct form the air passage. Alongwith the air sucked through the green mix, large amount of fine ore particles are also sucked in. These particles settle down in the wind-duct and require frequent removal. The conventional dust disposal system is 2-3 Box System. First box unloads dust into the second box. Finally, second/third box unloads the dust on the conveyor while the flap of the first box is kept closed. This ensures no air leakage into the wind duct. Drawbacks of the known art One of the major drawbacks of the wind ducts in the presently available sintering machine is that the flaps of the boxes being inaccessible, therefore, any mal-operation would lead to dislodging of any of the flaps. This results in tripping of the entire system with substantial time to repair/which would not prove to be cost effective for the system operation. Another disadvantage of the presently available sinter machine is that, due to mal-operation bigger lumps or other foreign particles may get stuck up in between the flap and the flap seat. This being inaccessible, air leakage through this takes place. So, the dust disposal is often disrupted resulting in huge dust accumulation in the wind duct and subsequent improper air dynamics within the wind duct. One more disadvantage of the presently available dust disposal system lies in the complexities for changing the box assemblies, which requires more time. In addition to such 2/3 box type disposal systems, one or more systems are in use in which dust is discharged through a dust leg submerged in water. The dust accumulated in water tank is subsequently disposed by means of a chain conveyor. The system is cumbersome and prone to frequent breakdown. Therefore, there is a need of an improved dust disposal system, which is simple yet cost effective and is highly sensitive. Objects of the present invention One of the basic objects of the present invention is to provide an improved dust disposal unit for sintering machine wherein the disposal operation would be 100% reliable. Another object of the present invention is to provide an improved dust disposal system for sintering machine comprising the above unit wherein the disposal operation would be 100% reliable. Another object of the present invention is to provide an improved dust disposal system for sintering machine with a simple and cost effective maintenance. A further object of the present invention is to provide a light dust disposal system, which would be easy to repair at the time of any mal-operation. Another object of the present invention is to provide single flap units, which are automatically excited by pneumatic activation in a predetermined fashion through a PLC. Another object of the present invention is to provide an improved dust disposal system with continuous condition monitoring of the dust accumulation in the wind duct. One more object of the present invention is to increase the flexibility in changing sequence of dust removal from various dust hoppers using multiple single flap units used in the dust disposal system. /Summary of the invention Thus according to main aspect of the present invention there is provided a single flap dust disposal unit for wind duct of sinter machine comprising i) flap assembly in operative connection with hopper; ii) plurality of sensor means for detecting presence of materials to be removed; iii) actuator means in operative connection with the said flap assembly; said unit provided with control PLC which is adapted to receive inputs from the said sensor means and convey signals to said actuator means for dust disposal by the unit such that the unit is adapted to dust removal based on predetermined limits of dust content. According to another aspect of the present invention there is provided a single flap dust disposal system for wind duct of sinter machine, comprising multiple single flap dust disposal units, as mentioned above. Detailed description of the invention Each disposal unit of the system of invention is single flap in design. The design is very simple as it consists of very few elements. Actuator means comprises pneumatic cylinder in combination to the single flap unit. The flap is hinged to the link mechanism that connects the flap to the actuator. Hinges on flap and actuator arms ensure proper seating of flap. Small capped port for inspection and poking helps in clearing any jamming of dust in the hopper. A grill over the flap assembly arrests bigger particles coming into the flap assembly. There are sensor means provided at a suitable distance above the flap. The sensor gives signal to the activator to close the flap, ensuring small column of dust over the flap. This provides sealing for any air leakage through the flap. Conical flap and seat ensures good sealing. The bottom of the wind duct is provided with hoppers. Accumulation of dust in the wind duct is not uniform. As the material builds up in the hopper and the pipe of the assembly, the upper level sensor senses the presence of material and sends signal to the solenoid to operate the actuator. Similarly, the lower level sensor senses the absence of the material and provides signal for closing the actuator. As the actuator travels back the flap is closed. The hoppers unload the dust through the flap assemblies on to the conveyor. The flap is activated by pneumatic activation of the actuator means in a predetermined fashion through a PLC. The PLC comprises of an input unit, a comparator and an output unit. The input unit receives the upper or the lower level signals from the sensors and compares it with predetermined values. The PLC provides the signal for activation of the pneumatic activator. The activator keeps the flap open, disposing the dust on the conveyor below. When the sensor senses the vacuum, it gives signal to the activator to close. This ensures minimum height of the dust column to maintain sealing. The PLC selects simultaneous operation of flaps at different locations (according to the data manually fed by the operator) so that the dust can be uniformly loaded on the conveyor. This will avoid the overloading on conveyors. The sensor provides the signal for closing of the activators. Accordingly, the operator depending on his observation from time to time programs the PLC. In the multiple unit system of the present invention, depending upon the severity of dust accumulation, an appropriate sequence of valve operation can be selected. The complete dust disposal system has 25 to 30 dust hoppers. If dust collects more frequently in certain hoppers, say hopper 10 to 15, then these are opened every hour whereas, others having less dust accumulation are operated once in two hours. With respect to the sinter machine operating practice, program for frequency of dust unloading can be executed to open the flaps individually or as a group. In this way flexibility in operation is achieved. Once the operation cycle is completed the PLC as per the programmed sequence gives command to the actuator to operate. Brief description of accompanying drawings Figure 1 shows a conventional dust disposal system. Figure 2 shows the dust disposal unit of the present invention. Figure 3: Flow chart depicting the sequence of operation of dust unloading by the system of present invention Figure 1 describes the dust disposal assembly of conventional system. Box assembly (1) comprises 2-3 boxes, which are cascaded to one another. Actuator (2) is linked to the flap (5) through a link mechanism (4). In the figure a supporting structure (3) is found, which is connected to actuator (2) providing it a mechanical support. The lower surfaces of BOX-1 and BOX-2 are provided with flap assembly structures (6) and flaps (5). A flat plated conveyor skirt (7) is located above the belt conveyor (8), which again rests on the conveyor roller (9). In figure 2 sensor (10) senses the presence of material and gives signal to the solenoid to operate the actuator (11). A rod like structure (12) provides support to the pneumatic cylinder (11). A flat lamella like structure, flap (13) is found just beneath the valve seat (14). The cone shaped seat (14) provides perfect sealing to the flap (13). Flap (13) is connected to the pneumatic cylinder actuator (11) through a link mechanism (15). A thin rod-strip design actuator arm (16) is connected to both cylinder (11) and link mechanism (15) to operate the flap. A small lower level sensor (17) is located just below the upper level sensor (10) to close the flap (13) when the material is unloaded to a desired level. Sensor (10) and level sensor (17) are connected to the PLC (18), which is again connected to the pneumatic cylinder actuator (11). The cone shaped conveyor skirt (19) encapsulates the flap (13) and valve seat (14). Conveyor skirt (19) is designed in such a way, that it can arrest spillage when the material is being unloaded to the conveyor assembly. The dust hopper (20) consists of grill (21) to arrest the bigger materials to flow into the hopper and pipe. In figure 3 the flow chart depicts the following steps, which are involved in the dust unloading operation for wind duct of sinter machine: At first signal is provided by conveyor to the sensor during the relay actuation. The sensor then senses the presence of material in the hopper and the pipe and sends signals to the PLC. In the next step the actuator operates as directed by the PLC to open the flap unloading the material on the conveyor. In the next step the sensor senses the absence of material in the hopper and the pipe thus closing the actuator through the PLC. After that again new signals are generated by the PLC for other actuator to operate. We claim 1) A single flap dust disposal unit for wind duct of sinter machine comprising i) flap assembly in operative connection with hopper (20); ii) plurality of sensor means (10, 17) for detecting presence of materials to be removed; iii) actuator means (11) in operative connection with the said flap assembly; said unit provided with control PLC (18) which is adapted to receive inputs from the said sensor means (10, 17) and convey signals to said actuator means (11) for dust disposal by the unit such that the unit is adapted to dust removal based on predetermined limits of dust content. 2) A single flap dust disposal unit as claimed in claim 1 wherein the PLC (18) comprises an input unit adapted to receive signals from sensor means (10,17), comparator and an output unit adapted for sending the excitation signal to the actuator means (11). 3) A single flap dust disposal unit as claimed in claims 1 to 2 wherein the comparator is provided with predetermined values of the quantity of materials present in the disposal unit and is adapted to compare the said values with the obtained by the sensor means (10,17). 4) A single flap dust disposal unit as claimed in claims 1 to 3 wherein the said unit has a plurality of sensor means located at a suitable distance from the flap. 5) A single flap dust disposal unit as claimed in claims 1 to 4 wherein the sensor means comprises upper level sensors (10) and lower level sensors (17). 6) A single flap dust disposal unit as claimed in claims 1 to 5 with upper level sensors (10) adapted to sense the building up of material in the said unit and give signal to PLC (18). 7) A single flap dust disposal unit as claimed in claims 1 to 6 wherein said lower level sensors (17) are adapted to sense the absence of material in the unit closing the actuator (11). 8) A single flap dust disposal unit as claimed in claims 1 to 7 wherein said flap assembly comprises triangle shaped conveyor skirt (19) encapsulating a part of the hopper pipe. 9) A single flap dust disposal unit as claimed in claims 1 to 8 wherein the conveyor skirt (19) is adapted to arrest the spillage of the material. 10)A single flap dust disposal unit as claimed in claims 1 to 9 wherein said flap assembly comprises a solenoid adapted to operate the actuator means. 11)A single flap dust disposal unit as claimed in claim 10 wherein the solenoid is adapted for link mechanism (15) between the actuator (11) and the flap. 12)A single flap dust disposal unit as claimed in claim 1 to 11 wherein said flap assembly comprises a conical valve seat (14) adapted to ensure perfect sealing against air leakage. 13)A single flap dust disposal unit as claimed in claims 1 to 12 wherein said flap assembly comprises a hinged flap (13). 14)A single flap dust disposal unit as claimed in claim 1 to 13 wherein the hinged flap (13) is adapted to clear any jamming of dust in the hopper. 15)A single flap dust disposal unit as claimed in claims 1 to 14 wherein said flap assembly is further provided with grills (21) over the flap assembly adapted to resist movement of the bigger particles. 16)A single flap dust disposal system for wind duct of sinter machine, comprising plurality of single flap dust disposal units, as claimed in any preceding claim. 17)A single flap dust disposal system as claimed in claim 16 adapted to be controlled by the PLC to operate the units at variable frequency and sequence based on the level of accumulation of material in them. 18)A single flap dust disposal unit substantially as herein described and illustrated with reference to the accompanying figures. 19)A single flap dust disposal system for wind duct of sinter machine, comprising plurality of single flap dust disposal units as herein described. A single flap dust disposal unit for wind duct of sinter machine comprising flap assembly (13), a hopper (20), plurality of sensor means (10,17) for detecting presence of materials to be removed, actuator means (11) in operative connection with the said flap assembly (13) and PLC (21) receiving inputs from the said sensor means and conveying signals to said actuator means (11).

Documents:

00809-kol-2004-abstract.pdf

00809-kol-2004-claims.pdf

00809-kol-2004-correspondence.pdf

00809-kol-2004-description (complete).pdf

00809-kol-2004-drawings.pdf

00809-kol-2004-form 1.pdf

00809-kol-2004-form 18.pdf

00809-kol-2004-form 2.pdf

00809-kol-2004-form 3.pdf

00809-kol-2004-letter patent.pdf

00809-kol-2004-pa.pdf

00809-kol-2004-reply f.e.r.pdf

809-KOL-2004-FORM 27.pdf