TECHNICAL FIELD
[001] Embodiments disclosed herein relate to oxygen probe cleaning, and more particularly to control the carbon potential during oxygen probe cleaning.
BACKGROUND
[002] In an industrial furnace, oxygen probes are used to control the furnace 5 atmosphere. During production, carbon deposits accumulate on the probe, leading to an increase in the carbon potential in the furnace atmosphere. Regular cleaning by purging of oxygen probe tip is required for avoiding excess deposit of carbon on zirconium metal. In existing systems, the purging is causing wrong interpretation by oxygen probe due to the presence of reference air and this causes excess flow of undesired carburizing 10 gases into the furnace. Due to increase in carbon potential, the process becomes unstable and can lead to undesired result(s) during production.
OBJECTS
[003] The principal object of embodiments herein is to control the carbon potential value during purging in a furnace. 15
[004] Another object of embodiments herein is to control the carbon potential value during purging in a furnace using an external relay.
[005] 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 20 following descriptions, while indicating at least one embodiment 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. 25
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BRIEF DESCRIPTION OF FIGURES
[006] Embodiments herein are illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which: 5
[007] Fig. 1 is the electrical circuit diagram arrangement provided to control the carbon potential of a furnace during oxygen probe purging, according to embodiments as disclosed herein; and
[008] Fig. 2a and 2b are the graphs that show the effects of variations in the carbon potential values, according to embodiments as disclosed herein. 10
[009] Fig. 3 is a flow diagram illustrating a method for controlling a carbon potential of a furnace, according to embodiments as disclosed herein.
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DETAILED DESCRIPTION
[0010] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are 5 omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein. 10
[0011] The embodiments herein control the flow of carbon potential by restricting the flow of gases. Referring now to the drawings, and more particularly to FIGS. 1 through 3, where similar reference characters denote corresponding features consistently throughout the figures, there are shown embodiments.
[0012] FIG. 1 is the electrical circuit diagram arrangement provided to control 15 the carbon potential of a furnace during oxygen probe purging, according to embodiments as disclosed herein. In an embodiment, the circuit (100) includes a relay contact of RL5 (102), a solenoid for purging (104), an external relay (108) and a controller (106). In an embodiment, the relay contact of RL5 (102) can be a push button type input from a Human Machine Interface. In an embodiment, the controller can be 20 connected in parallel to the relay contact of RL5 (102). In an embodiment, the controller (106) can be an automatic process input from Eurotherm make CP controller. The external relay (108) can be in parallel to the solenoid (104). When the solenoid for purging is ON, the relay contact R1 (108) will be ON. In an embodiment, when the external relay contact of R1 (108) is Normally Closed, the flow of gases through the 25 solenoid (110) is stopped, thereby controlling the flow of carbon potential of the furnace. The flow of carbon potential is controlled by restricting the flow of LPG gases through the solenoid (110).
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[0013] In an embodiment, an atmospheric air and purging air flows through the oxygen probe. In an embodiment, the purging air is adapted to clean the excess carbon on a suitable metal (such as Zirconium, titanium, hafnium, carbon, and so on).
[0014] FIG. 2a and 2b are the graphs that show the effects of variations in the carbon potential values. FIG. 2a represents a graph that shows the peak value of 5 undesired carbon potential under normal condition. Under normal condition, at (202) the carbon potential is above the set point due to the excess flow of carbodrip during purging, as depicted in FIG. 2a.
[0015] FIG. 2b represents a smooth graph for carbon potential values that can be achieved according to the embodiments disclosed herein. The carbon potential is within 10 the allowed range as depicted at (204) of FIG. 2b and the excess flow is eliminated.
[0016] Fig. 3 is a flow diagram illustrating a method for controlling a carbon potential of a furnace, according to embodiments as disclosed herein. At step 302, the method includes opening an external relay, when a solenoid is ON for purging. In an embodiment, the external relay is connected in parallel to the solenoid (104). At step 15 304, the flow of gases is stopped through the solenoid.
[0017] The various actions, acts, blocks, steps, or the like in the method and the flow diagram 300 may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some of the actions, acts, blocks, steps, or the like may be omitted, added, modified, skipped, or the like without departing from 20 the scope of the invention.
[0018] The embodiments disclosed herein can be implemented through at least one software program running on at least one hardware device and performing network management functions to control the network elements. The network elements include blocks, which can be at least one of a hardware device, or a combination of hardware 25 device and software module.
[0019] 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 30
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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 embodiments and examples, those skilled in the art will recognize that the 5 embodiments and examples disclosed herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

We claim:
1. A method of controlling a carbon potential of a furnace, the method comprising:
stopping flow of gases through a solenoid (110) by opening an external relay (108) when a solenoid (104) is ON for purging, wherein the external relay (108) is connected in parallel to the solenoid (104).
2. The method, as claimed in claim 1, wherein the carbon potential of the furnace is controlled during oxygen probe purging.
3. The method, as claimed in claim 1, wherein a relay contact (102) is ON when the solenoid (104) is ON for purging.
4. A circuit (100) for controlling a carbon potential of a furnace, the system (100) comprising an external relay (108), wherein the external relay (108) is open when the solenoid (104) is ON for purging, hereby stopping flow of gases through the solenoid (110), wherein the external relay (108) is connected in parallel to the solenoid (104).
5. The circuit, as claimed in claim 4, wherein the circuit is configured for controlling carbon potential of the furnace during oxygen probe purging.
6. The circuit, as claimed in claim 4, wherein the circuit further comprises a relay contact (102), wherein the relay contact (102) is ON when the solenoid (104) is ON for purging.