Claims:
1. A system for cleaning and drying an inner cover, comprising:
? a hydraulic header (101) and a pneumatic header (102) vertically supported by a common tower (103);
? the hydraulic header (101) connected to a liquid supply line (110) at a lower end of the hydraulic header (101);
? the pneumatic header (102) connected to an air supply line (120) at a lower end of the pneumatic header (102);
? a plurality of pneumatic nozzles (104) configured over the length of the pneumatic header (102);
? a plurality of branch pipe (105) configured over the length of the hydraulic header (102), each branch pipe (105) coupled with a hydraulic nozzle (106); and
? a controller being coupled to the hydraulic header (101) and/or the pneumatic header (102) configured to control the motion of the hydraulic nozzles (106) and the pneumatic nozzles (104).
2. The system as claimed in claim 1, wherein the branch pipe (105) is coupled with a linear actuator and the hydraulic nozzle (106) are mounted on the linear actuator, the linear actuator provides linear movement to the hydraulic nozzle (106) along the branch pipe (105).
3. The system as claimed in claim 1 or claim 2, wherein the plurality of pneumatic nozzles (104) are uniformly distributed along the length of the pneumatic header (102).
4. The system as claimed in claim 3, wherein the distance between each adjacent pneumatic nozzle (104) is equal and the angle between each adjacent pneumatic nozzle (104) is same.
5. The system as claimed in claim 1 or claim 2, wherein the plurality of branch pipes (105) are uniformly distributed along the length of the hydraulic header (101).
6. The system as claimed in claims 5, wherein the distance between each adjacent branch pipe (105) is equal and the angle between each adjacent branch pipe is same (105).
7. The system as claimed in any one of claims 1 to 6, wherein the pneumatic nozzle (104) and/or the hydraulic nozzle (106) supports dual axis of rotation.
8. The system as claimed in any one of claims 1 to 7, wherein the liquid supply line (110) comprises a pressurized liquid source (111), a filtration unit (112), a pump motor set (11), a pressure gauge (117) and a plurality of ball valve (118).
9. The system as claimed in any one of claims 1 to 8, wherein the air supply line (120) comprises a pressurized air source (121), an air drying unit (122), a pressure gauge (123) and a plurality of ball valve (124).
10. The system as claimed in any one of claims 1 to 9, wherein the liquid supply line (110) provides water to the hydraulic header (101).
11. The system as claimed in any one of claims 1 or 10, wherein the air supply line (120) provides dry air to the pneumatic header (102).
12. The system as claimed in any one of claims 1 to 11, wherein the controller configured to control the axial rotation along both axis of each of the pneumatic nozzle (104) and/or the hydraulic nozzle (106).
13. The system as claimed in any one of claims 1 to 12, wherein the controller configured to control the tilting angle of each of the and the pneumatic nozzle (104), and/or the hydraulic nozzle (106).

14. The system as claimed in any one of claims 1 to 13, wherein the controller is configured to control an output of each of the pneumatic nozzle (104), and/or the hydraulic nozzle (106).
, Description:F O R M 2
THE PATENTS ACT, 1970
(39 of 1970)
The Patent Rule, 2003
&

COMPLETE SPECIFICATION
(See section 10 and rule 13)

“A SYSTEM FOR COMBINED COKE QUENCHING”
By

STEEL AUTHORITY OF INDIA LIMITED, A GOVERNMENT OF INDIA ENTERPRISE, HAVING ITS ADDRESS AT RESEARCH & DEVELOPMENT CENTRE FOR IRON & STEEL, DORANDA, RANCHI-834002, STATE OF JHARKHAND, INDIA

The following specification particularly describes the invention and the manner in which it is to be performed
FIELD OF THE INVENTION
The present invention relates to a cleaning and drying system. Particularly, the present invention relates to a system for cleaning and drying an annealing furnace inner cover.
BACKGROUND OF THE INVENTION
Batch annealing is one of the most important processes in cold rolling mills which dominate the final product quality of cold rolled coils. Some deformation given to the coils at room temperature during the cold rolling process significantly reduces the ductility and formability of cold rolled coils. This necessitates annealing, where the cold rolled coils get stress relieved through the mechanisms of recovery, recrystallization and grain growth. Annealing of cold rolled steel coils are carried out in a batch annealing furnace with hydrogen atmosphere is used to anneal the cold rolled coils for improving its formability. A batch annealing furnace consists of an annealing base, an inner cover and a movable bell-type furnaces. In the batch annealing process, three to five cylindrical steel coils are stacked on a furnace base. The inner cover is placed over the coil stack, sealed at the base and is filled with the hydrogen gas to prevent the coils from getting oxidized under high temperature. After this, the heating hood (furnace) is lowered onto the stack. The annealing is performed as the furnace heats up the inner cover, the heat is then radiated and convected to the coils causing them to heat up.
During annealing, the rolling oil carried by the cold rolled coils generates a carbon or carbonaceous products and the generated carbonaceous matter gets deposited on the inner surface of the inner cover.
Frequent bulging and cracking of these inner covers was observed (i.e., at least 10-12 inner covers per month) leading to reduction in availability of batch annealing furnace. In order to identify the causes of frequent failures, various studies were carried out with cracked and bulged samples of the inner cover. These samples were investigated by visual inspection, chemical analysis and microstructural examination. Visual inspection revealed the deposition of soot at the inner surface. Microstructural examination and energy dispersive spectroscopy (EDS) analysis indicated the formation of carbide network and precipitations of sigma phase in the matrix. Analyses of the results suggest that the carburization attack of the hydrocarbon gas generated at the annealing temperature from the rolling oil adherent to the coils favored the formation of carbides network at the inner cover matrix. Formation of carbides associated with depletion of alloying elements from the matrix deteriorates the mechanical properties and sensitizes the steel to corrosion attack because of reduction of chromium from the matrix of the inner cover material making it prone to bulging and cracking.
In a cold rolling mill, the repair of each cracked inner cover takes around 5 hours. Due to bulging of inner cover the furnace gets stuck up and increases the cooling time by 12-14 hr. Because of these problems, the downtime of around 110 hr/month was observed resulting in the loss in production. Presence of thick carbonaceous layer is considered to have adverse effects on life of inner covers. It ultimately leads to reduction in availability and productivity of the batch annealing furnace.
In the current scenario, there is no proper cleaning system for an efficient removable of the carbonaceous deposits from the inside surface of the inner cover. If required, the inner cover is placed in a horizontal position and cleaned manually with the help of brush. However, such cleaning is not practice regularly because the process is inconvenient and unsafe for the human labor.
Therefore, there is a need in the art for a system to clean the inner cover of annealing furnace with minimum or without any human intervention.
SUMMARY OF THE INVENTION
An aspect of the present invention is to address at least the above-mentioned problems and/or disadvantages and to provide at least the advantages described below.
The main objective of the present invention is to provide a system for cleaning and drying an inner cover of annealing furnace with minimum human intervention.
Accordingly the present invention in an embodiment provides a system for cleaning and drying an inner cover, comprising a hydraulic header and a pneumatic header vertically supported by a common tower; the hydraulic header is connected to a liquid supply line at a lower end of the hydraulic header; the pneumatic header is connected to an air supply line at a lower end of the pneumatic header; a plurality of pneumatic nozzles are distributed over the length of the pneumatic header; the hydraulic header has a plurality of branch pipe distributed over the length of the hydraulic header, each branch pipe is coupled with a hydraulic nozzle; a controller coupled to the hydraulic header and the pneumatic header configured to control the motion of the hydraulic nozzles and the pneumatic nozzles.
According to an embodiment of the present invention, the branch pipe is coupled with a linear actuator and the hydraulic nozzle are mounted on the linear actuator, the linear actuator provides linear movement to the hydraulic nozzle along the branch pipe.
According to an embodiment of the present invention, the plurality of pneumatic nozzles are uniformly distributed over the pneumatic header with respect to the length of the pneumatic header and orientation angle of the pneumatic nozzles, such that the distance between each adjacent pneumatic nozzle is same and the angle between each adjacent pneumatic nozzle is same.
According to an embodiment of the present invention, the plurality of branch pipe uniformly distributed over the hydraulic header with respect to the length of the hydraulic header and orientation angle of the branch pipe, such that the distance between each adjacent branch pipe is same and the angle between each adjacent branch pipe is same.
In this respect, before explaining the current embodiments of the system for cleaning and drying the inner cover in detail, it is to be understood that the system for cleaning and drying the inner cover is not limited in its applications to the details of construction and arrangements of the components set forth in the following description or illustration. Those skilled in the art will appreciate that the concept of this disclosure may be readily utilized as a basis for the design of other structures, methods, and systems for carrying out the several purposes of the system for cleaning and drying the inner cover.
It is therefore important that the claims be regarded as including such equivalent construction insofar as they do not depart from the spirit and scope of the system for cleaning and drying system the inner cover. It is also to be understood that the phraseology and terminology employed herein are for purposes of description and should not be regarded as limiting.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are included to provide a further understanding of the invention are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and together with the description serve to explain the principles of the invention. They are meant to be exemplary illustrations provided to enable persons skilled in the art to practice the disclosure and are not intended to limit the scope of the appended claims.
Figure 1 is the layout of the annealing furnace.
Figure 2(a) is the front view of an embodiment of the present invention.
Figure 2 (b) is the side view of an embodiment of the present invention.
Figure 2 (c) is the front view of an embodiment of the present invention illustrating hydraulic headers and hydraulic nozzles.
Figure 2 (d) is the front view of an embodiment of the present invention illustrating pneumatic headers and pneumatic nozzles.
Figure 2 (e) is the structural representation of an embodiment of the present invention.
Figure 3 (a) is the top view of fig. 2(a).
Figure 3 (b) is the top view of fig. 2(c).
Figure 3 (c) is the top view of fig. 2(d).
Figure 4 (a) is a schematic view of liquid supply line according to an embodiment of the present invention.
Figure 4 (b) is a schematic view of air supply line according to an embodiment of the present invention.
Figure 5 illustrates 3600 horizontal and vertical rotation of the hydraulic nozzle.
Figure 6 illustrates 3600 horizontal rotation of the hydraulic nozzle.
Figure 7 illustrates the pneumatic nozzle.
Throughout the drawing, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures.
DETAILED DESCRIPTION OF THE INVENTION
The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of the invention as defined by the description. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.
The terms and words used in the following description are not limited to the bibliographical meanings but are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of the present invention is provided for illustration purpose only.
It is to be understood that the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise.
Figure 1 shows the structural representation of an annealing furnace (1). The furnace (1) includes a heating hood (2), an inner cover (3) and a plurality of coils (4). In the batch annealing process, three to five cylindrical steel coils (4) are stacked on a furnace (1) base. The inner cover (3) is placed over the coil (4) stack, sealed at the base and is filled with the hydrogen gas to prevent the coils (4) from getting oxidized under high temperature. After this, the heating hood (2) is lowered onto the stack. The annealing is performed as the heating hood (2) heats up the inner cover (3), the heat is then radiated and convected to the coils (4) causing them to heat up.
Figure 2 (a) – figure 2 (e) shows a system for cleaning and drying an inner cover of annealing furnace (100) comprising a hydraulic header (101) and a pneumatic header (102) vertically supported by a common tower (103). The hydraulic header (101) connected to a liquid supply line at a lower end of the hydraulic header (101). The pneumatic header (102) connected to an air supply line at a lower end of the pneumatic header (102). A plurality of pneumatic nozzles (104) distributed over the length of the pneumatic header (102). In an embodiment, the pneumatic nozzles (104) are uniformly distributed over the length of the pneumatic header (102). In other embodiment, the plurality of pneumatic nozzles (104) are uniformly distributed over the pneumatic header (102) with respect to the length of the pneumatic header (102) and orientation angle of the pneumatic nozzles (104), such that the distance between each adjacent pneumatic nozzle (104) is same and the angle between each adjacent pneumatic nozzle (104) is same.
The hydraulic header (101) has a plurality of branch pipe (105) distributed over the length of the hydraulic header (101). The other end of each branch pipe (105) is coupled with a hydraulic nozzle (106). In an embodiment of the present invention, the plurality of the branch pipe (105) are uniformly distributed over the hydraulic header (101) with respect to the length of the hydraulic header (101). In another embodiment of the present invention, the plurality of branch pipe (105) are uniformly distributed over the hydraulic header (101) with respect to the length of the hydraulic header (101) and orientation angle of the branch pipe (105), such that the distance between each adjacent branch pipe (105) is same and the angle between each adjacent branch pipe (105) is same. In one another embodiment of the present invention, each branch pipe (105) is coupled with a linear actuator (not shown in the figure) and each hydraulic nozzle (106) is mounted on the linear actuator, the linear actuator provides linear movement to the hydraulic nozzle (106) along the branch pipe (105). In an embodiment of the present invention the linear actuators can be mechanical actuators, electro-mechanical actuators, piezoelectric actuators, electric actuators, hydraulic actuators or pneumatic actuators.
In one another embodiment, the hydraulic nozzle (106) is attached perpendicularly to the branch pipe (105) such that the hydraulic nozzles (106) are parallel to the hydraulic header (101).
A controller (not shown in the figure) is coupled to the hydraulic header (101) and the pneumatic header (102) configured to control the motion of the hydraulic nozzles (106) and the pneumatic nozzles (104). The controller follows the commands provided by the user. In an embodiment of the present invention, the controller configured to control the axial rotation of each of the hydraulic nozzle (106) and the pneumatic nozzle (104) along both the axis individually. In another embodiment, the controller is configured to control the tilting angle of each of the hydraulic nozzle (106) and the pneumatic nozzle (104) individually. In one another embodiment, the controller is configured to control the output of each of the hydraulic nozzle (106) and the pneumatic nozzle (104) individually.
The inner covers are generally made of 309S stainless steel. The standard outer diameter of inner cover is 2318 mm with wall thickness of 6 mm and height of 7481 mm. In an embodiment the height of hydraulic header is 6800 mm, the height of a pneumatic header is 5500 mm.
Fig. 3(a), fig. 3(b) and fig. 3(c) shows the top view of fig. 2(a), fig. 2(c) and fig. 2(d) respectively. Fig 3 (a) shows the angular arrangement of branch pipe (105) and pneumatic nozzle (104) with respect to the headers (101,102). Figure 3 (b) shows the angular arrangement of branch pipe (105) with respect to the hydraulic header (101). Fig 3 (c) shows the angular arrangement of pneumatic nozzle (104) with respect to the pneumatic header (102).
Figure 4 (a) shows the liquid supply line (110) comprising a pressurised liquid source (111), a filtration unit (112), a pump motor set (113), a check valve (114), a minimum flow line (115), a pressure relief valve (116), a pressure gauge (117) and a plurality of ball valve (118). The fluid from the liquid source (111) goes to the filtration unit (112), the filtered fluid enters the pump motor set (113). The ball valve (118) sets a pressure for the fluid as per the requirement of the controller and the outlet of the liquid supply line (111) is connected to the hydraulic header (101). In an embodiment, the filtration unit (112) is a basket filter. In an embodiment, the capacity of the filtration unit (112) is in the range of 12 m3/hr – 20 m3/hr at 5 bar and the mesh filter size is in the range of 200-250 micron. In another embodiment, the pump motor set (113) is having a minimum capacity 10-15 m3/hr and the output power is 10-15 kW.
Figure 4 (b) shows an air supply line (120) comprising a pressurised air source (121), an air dryer (122), a pressure gauge (123) and a plurality of ball valve (124). The pressurised air from the air source (121) enters the air dryer (122). Then the ball valve (124) sets a pressure for the dry air as per the requirement of the controller and the outlet of the air supply line (120) is connected to the pneumatic header (102).
Figure 5 and figure 6 illustrates 3600 horizontal and vertical rotation of the hydraulic nozzle (106). The nozzle head (141) rotates 3600 along A-A axis as shown in the figure 5. Figure 6 illustrates 3600 horizontal rotation of the hydraulic nozzle (106). The nozzle tip (142) rotates 3600 along B-B axis as shown in the figure 5. In an embodiment of the present invention, the hydraulic nozzle (106) supports dual axis of rotation. In another embodiment of the present invention, the narrowest cross-section of hydraulic nozzle (106) is in the range of 1.2-1.8 mm in diameter with a flow rate in the range of 35 - 45 litre/min at 4-6 bar.
The linear actuator and the dual axis rotating hydraulic nozzle (106) can efficiently clean the entire inner cover form inside.
Figure 7 illustrates the static pneumatic nozzle (104) according to an embodiment of the invention. In other embodiment of the present invention, the pneumatic nozzle (104) supports dual axis of rotation. In another embodiment of the present invention, the narrowest cross-section of pneumatic nozzle (104) is in the range of 0.8-1.2 mm in diameter with a flow rate in the range of 30-45 Nm3 /hr at 3-4 bar.
In an embodiment of the present system, the liquid supply line (110) provides water to the hydraulic header (101). In an embodiment of the present system, the air supply line (120) provides dry air to the pneumatic header (103).
In an embodiment of the present invention, a base is provided with a hole. The hole is a clearance for the tower such that the base is not in the contact with the tower. The inner cove is kept on the base. The base has provisions to rotate along the axis of the tower. As the base rotates the inner cover also rotates thereby provided more efficient cleaning.
The present system is able to clean the entire inside surface of the inner cover within 45-60 minutes using high pressure water jet and subsequently dry them using dry compressed air. Experimental trials were carried out with the present system. After the completion of water cleaning and drying operation, the inside surface of the inner cover was visually inspected. Removal of carbonaceous deposits from the inner surface of inner cover was observed. After satisfactory visual inspection, a surface contamination test was performed by using a conventional tape test. In each inner cover, tape test was carried out at different locations to evaluate the effect of cleaning. A substantial reduction of surface contamination and surface reflectance was observed by conventional tape test. An average of tape test results on various experimental trials of cleaned inner cover revealed that surface reflectance in conventional tape test by over 80% with the cleaned inner cover.
The present system can used to clean and dry the inner cover of any furnace. The present system will improve the overall availability of inner cover at all annealing furnaces leading to improved productivity of the shop.
Although there has been shown and described the preferred embodiment of the present invention, it will be readily apparent to those skilled in the art that modifications may be made thereto which do not exceed the scope of the appended claims. Therefore, the scope of the invention is only to be limited by the following claims.