DESC:FIELD OF INVENTION

The present invention relates to automobile painting shop. In particular, the present invention relates to automobile body paint baking ovens. More particularly, the present invention relates to an automatically operated dual-fuel paint baking oven burner.

BACKGROUND OF THE INVENTION

In any automobile manufacturing plant, one of the most important activities is the process of painting the automobile, be it for protecting the vehicle body from harsh environmental, or for enhancing aesthetic appeal of the automobile in the eyes of the prospective owners. Normally, the automobile metallic bodies are coated with several layers of primer, paint and top coat at elevated temperature and for a predetermined duration during paint baking process. This paint baking process involves: either three coats of painting, i.e. primer surface, base coat and top coat plus three bakes or two coats of painting, i.e. primer surface and top coat plus two bakes. Generally, the automobile paint-baking cycle includes seven process stages: pre-cleaning, multistage phosphate pretreatment, electro-deposition coating, PVC underbody coating and sealing application, filler primer application and base and/or top coat application and finally wax application. The conventional automobile manufacturing plant employs LNG incinerators on paint-baking lines. However, at present, there is a trend to replace these by dual-fuel gas train burners, which predominantly use compressed natural gas (CNG) and liquefied petroleum gas (LPG).

DISADVANTAGES WITH THE PRIOR ART

The dual-fuel gas train burners are provided in such paint-baking ovens, which have changeover facility for LPG to LNG and vice-versa. However, this changeover is to be carried out manually. The configuration of LPG burner and CNG burners are different from the point of view of the locations of the concentric supply of air and fuel with respect to each other.
For example, by selecting LPG, the air flow should be from a pipe surrounding the fuel supply pipe of the duel-fuel burner assembly (Figure 3), whereas by selecting LNG, air supply pipe should be surrounded by the fuel supply pipe of the dual-fuel burner assembly (Figure 4).

Therefore, often there is a risk of explosion on the burner side due to a mistake in air-fuel combination during any manual changeover from LPG to LNG and vice-versa.

OBJECTS OF THE INVENTION

Some of the objects of the present invention - satisfied by at least one embodiment of the present invention - are as follows:

An object of the present invention is to provide an automatically operated dual-fuel gas train for paint baking oven burner.

Another object of the present invention is to provide an automatically operated dual-fuel gas train for paint baking oven burner provided with trouble-free fuel-selection port.

Still another object of the present invention is to provide dual-fuel gas train for paint baking oven burner having electronically operated fuel-selection port.

Yet another object of the present invention is to provide an automatically operated dual-fuel gas train for paint baking oven burner, which eliminates potential unsafe condition for the operator at fuel burner gas trains.

These and other objects and advantages of the present invention will become more apparent from the following description when read with the accompanying figures of drawing, which are, however, not intended to limit the scope of the present invention in any way.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided an automatically operated dual-fuel gas train of paint baking oven burners, wherein the gas train comprises:

• a duel-fuel burner connected to a plurality of fuel supply lines and air hoses;
• at least two air-hoses supplying air for burning selected fuel;
• at least two fuels for selection therebetween; the fuels being supplied via fuel supply lines fitted with a respective control valves to control the fuel supply;
• a plurality of micro switches installed on the air selection port for connecting the air selection port to the air hoses;
• a fuel selection valve for selecting the fuel to be burned for operating the paint baking oven; the valve connected to the dual fuel burner via interchangeably fuel supply control valves;
• a control panel electrically connected to the air selection port, fuel selection valve and the fuel control valves;

wherein the control panel is programmed to control the dual-fuel burner operation.

Typically, the control panel comprises:

• a burner controller;
• a microprocessor;
• a fuel-selection switch for selecting a first fuel or a second fuel for burner operation;

wherein the burner controller is electrically connected to the fuel selection valve and the fuel selection valve is connected to the dual-fuel burner by means of a respective fuel line connected via fuel supply control valve for supplying the automatically selected fuel.

Typically, the control panel comprises a burner controller, a microprocessor and a fuel-selection switch for selecting one of the two fuels to be supplied via fuel-selection valve and the microcontroller is a Programmable Logic Controller (PLC).

Typically, at least a pair of micro-switches each is provided on a respective air hose connected to the air selection port.

Typically, at least a micro-switch each is provided on the respective air hose connected to air selection port.

Typically, a T-shaped clamp is provided for clamping a respective air-hose at either end thereof to prevent an inadvertent interchange of the air-hoses.

Typically, the T-shaped clamp is slidable between a first position and a second position thereof to prevent inadvertent interchange of the air hoses.

Typically, the fuels are Liquefied Petroleum Gas (LPG) and Liquefied Natural Gas (LNG).

In accordance with the present invention, there is also provided a method for electronically operating a dual-fuel gas train of paint baking oven burners, the method comprising the steps of:

• selecting a fuel by means of the fuel selection switch;
• connecting the air-hoses to a respective air hose to the dual-fuel burner by closing the levers of two micro switches and opening the levers of the other two micro switches;
• supplying the electrical signals of the micro switches to the programmer logic controller (PLC) of the control panel;

wherein the burner sequence is started only after receipt of the confirmation of correct fuel selection at the fuel-selection valve.

Typically, the bracket or T-shaped metal clamp is installed between the two air-hoses for clamping a respective air hose; the bracket or T-shaped metal clamp slid between a first position and a second position thereof to select the targeted air hose connection and thereby to prevent an inadvertent interchange of the air hoses.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The present invention will be briefly described with reference to the accompanying drawings, which include:

Figure 1 shows a conventional dual-fuel gas train for paint baking oven burner in the paint-shop of an automobile manufacturing plant.

Figure 2 shows a dual-fuel gas train programmed to electronically operate the fuel-selection port of the paint baking oven burner configured in accordance with the invention fitted in the paint-shop of an automobile manufacturing plant.

Figure 3 shows a cross-sectional view of the typical arrangement of fuel and air mixing pipes, when LPG option is selected for operating the dual-fuel gas train for paint baking oven burner in the paint-shop of an automobile plant.

Figure 4 shows a cross-sectional view of the typical arrangement of fuel and air mixing pipes, when LNG option is selected for operating the dual-fuel gas train for paint baking oven burner in the paint-shop of an automobile plant.

Figure 5 illustrates a detailed block diagram of the overall system of the electronically operated fuel-selection port fitted for the first embodiment configured in accordance with the invention in the dual-fuel gas train for paint baking oven burner in the paint-shop of an automobile manufacturing plant.

Figure 6 illustrates a detailed block diagram of the overall system of the electronically operated fuel-selection port fitted for the second embodiment configured in accordance with the invention in the dual-fuel gas train for paint baking oven burner in the paint-shop of an automobile manufacturing plant.
Figure 7a shows a dual-fuel gas train programmed to electronically operate the fuel-selection port of the paint baking oven fitted in the paint-shop of an automobile manufacturing plant as shown in Fig. 6 by using bracket or T-clamp in its first position.

Figure 7b shows the bracket 199 in the second position thereof.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS

In the following, different embodiments of the present invention will be described in more details with reference to the accompanying drawings without limiting the scope and ambit of the present invention in any way.

Figure 1 shows a conventional dual-fuel gas train for paint baking oven burner in the paint-shop of an automobile manufacturing plant. The ports 50, 51 and 52, 53 are connected to the respective air hoses 190 and 170.

Figure 2 shows a dual-fuel gas train programmed to electronically operate the fuel-selection port of the paint baking oven burner configured in accordance with the first embodiment of the present invention and fitted in the paint-shop of an automobile manufacturing plant. Here, the air hose 190 is connected to the port 51 to 50 and air hose 170 is connected to port 53 to 52. Four micro switches M1, M2 and M3, M4 are connected to respective ports 50, 51 and 52, 53 placed on the respective air hose 190 and 170.

Figure 3 shows a cross-sectional view of the typical arrangement of fuel and air mixing pipes, when LPG option is selected for operating the dual-fuel gas train for paint baking oven burner in the paint-shop of an automobile plant. Here, fuel supply port 10 and air-inlet port 12 are laterally provided in the concentrically disposed pipe-system consisting of an inner fuel-supply pipe 14 running inside an outer air-supply pipe 16 for mixing in dual-fuel burner 18.

Figure 4 shows a cross-sectional view of the typical arrangement of fuel and air mixing pipes, when LNG option is selected for operating the dual-fuel gas train for paint baking oven burner in the paint-shop of an automobile plant. The arrangement of fuel and air supply pipe is just the reverse of that shown in Figure 3. So, the fuel supply port 20 and air-inlet port 22 are laterally provided in the concentrically disposed pipe-system consisting of an inner air-supply pipe 24 running inside an outer fuel-supply pipe 26 for mixing in dual-fuel burner 28.

Figure 5 illustrates the detailed block diagram of the electronically operated system provided with a fuel-selection port for the first embodiment configured in accordance with the invention and fitted in the dual-fuel gas train for paint baking oven burner in the paint-shop of an automobile manufacturing plant. The dual-fuel burner control panel 150 includes a burner controller 152, a processor 154 and a fuel-selection switch 156, with the options of selecting a first fuel F1 or a second fuel F2. In addition, a fuel-selection valve 162 is also provided for supplying one of the two fuels as per the fuel selection options (F1 or F2) on the control panel 150. The fuel-selection valve 162 is in fluid-connection with the dual-fuel burner 128 by means of two pipes 164 and 166 carrying the two fuels, e.g. LNG and LPG respectively. Two valves 158 and 160 are respectively disposed on these two fuel pipes 164 and 166, which are electrically connected to the burner controller 152 for their opening and closure as per the fuel (F1 or F2) selected on the control panel 150. Four micro switches M1, M2, M3 and M4 are also connected to control panel 150 (shown in Figure 5) installed at air selection port 168 for preventing any possibility of a wrong selection of air hoses 170, 190 connected to the dual-fuel burner 128. The micro switches M1, M2; M3, M4 supply feedback to confirm that the correct fuel line is selected by the logic of Programmable Logic Controller (PLC). The burner starting program and sequence starts only after receiving confirmation of correct selection of fuel type.
Accordingly, valve 162 is connected to the correct fuel supply line 164 or 166 via valves 158 or 160.

Figure 6 illustrates another detailed block diagram of the overall system of the electronically operated fuel-selection port fitted for the second embodiment configured in accordance with the invention. Here, only two switches M1 and M4 are required because of the provision of a bracket 199 (Figure 7). During fuel change over, when air hose 190 and 170 connections are changed from one fuel F1 to another fuel F2, there is a possibility of interchange between two air hoses is observed, because there is no interlock to prevent this interchange of hoses. The interchange of hoses also poses a risk of explosion at the burner. So, to avoid this possibility of interchange between two air hoses, a bracket or T-shaped metal clamp 199 is installed (Figure 7).

Figure 7a shows a dual-fuel gas train programmed to electronically operate the fuel-selection port of the paint baking oven burner for the second embodiment shown in Figure 6. The bracket or T-shaped metal clamp 199 is installed to clamp the air hoses 190 and 170 at one thereof. The bracket 199 is configured to slide between the two positions, of which the first position is shown here. The micro switches M3 and M4 are removed and only two Micro switches M1 and M2 are operated by this clamp 199.

Figure 7b shows a dual-fuel gas train programmed to electronically operate the fuel-selection port of the paint baking oven burner for the second embodiment shown in Figure 6. Here, bracket 199 is shown in the second position thereof.

WORKING OF THE INVENTION:

In the Duel fuel oven burner gas trains, four air-inlet ports and two air-connection hoses are provided for selecting air. These air hoses are required to be connected to the respective specified ports (For LPG or LNG respectively). In case of a wrong selection of the air combination for LNG or LPG at the time fuel change over blast may took place inside burner. To avoid possibility of any such wrong selection of air hoses, four micro switches M1, M2; M3, M4 (shown in Figure 2), which are connected to control panel 150 (shown in Figure 5) are installed at air selection port 168. Some modifications (e.g. T-shaped metal clamp 199 in Figure 7) are also done in air hose connectors to operate these micro switches M1, M2; M3, M4. The feedback of these micro switches M1, M2; M3, M4 is supplied for selecting the fuel type in the logic of the Programmable Logic Controller (PLC). The burner starting program and sequence starts only after receiving the confirmation of correct selection of fuel type.

At the time of fuel change over to LNG, the Fuel selection switch is turned from F1 to F2, as shown in Figure 5. The fuel-selection valve 162 is turned from LPG to LNG, and the feed of this valve is given to the control panel 150 in Figure 5. The air hose 190 is connected from the port 51 to 50 (shown in Figure 2) and air hose 170 is connected from port 53 to 52 (as shown in Figure 5). The levers of the Micro switches M1 and M3 will be closed and the levers of Micro switches M2 and M4 will be opened. The electrical feedback of the Micro switches M1, M2, M3, and M4 is given to the control panel 150 in Figure 5. By using LNG fuel, the burner starting program and sequence starts only after receiving the confirmation of correct selection of fuel type i.e. fuel selection switch at F2, fuel-selection valve at LNG and close feedback of Micro switch M1 and M3. In a second embodiment of the present invention, to avoid the possibility of an interchange between two air hoses, a T-shaped metal clamp 199 is installed for clamping air hoses 190 and 170 to prevents interchange of hoses 170 and 190.

TECHNICAL ADVANTAGES AND ECONOMIC SIGNIFICANCE

The electronically operate the fuel-selection port of the paint baking oven burner in accordance with the present invention has the following advantages:

- Eliminates potential unsafe condition at Dual fuel burner gas trains.
- Safeguards the operator while working on the pain-baking over.
- Improves the moral of the operator
- Eliminates the chances of accidents
- Totally eliminates the human error
- Provides the safe working environment

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. The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. The description provided herein is purely by way of example and illustration. The various features and advantageous details are explained with reference to this non-limiting embodiment in the above description in accordance with the present invention. The descriptions of well-known components and manufacturing and processing techniques are consciously omitted in this specification, so as not to unnecessarily obscure the specification.

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, the skilled person will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments described herein and can easily make innumerable changes, variations, modifications, alterations and/or integrations in terms of materials and method used to configure, manufacture and assemble various constituents, components, subassemblies, assemblies and in terms of the size, shapes, orientations and interrelationships without departing from the scope and spirit of the present invention. It is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

The numerical values given of various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher or lower than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the disclosure unless there is a statement in the specification to the contrary.

Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, shall be understood to implies including a described element, integer or method step, or group of elements, integers or method steps, however, does not imply excluding any other element, integer or step, or group of elements, integers or method steps.

The use of the expression “a”, “at least” or “at least one” shall imply using one or more elements or ingredients or quantities, as used in the embodiment of the disclosure in order to achieve one or more of the intended objects or results of the present invention. ,CLAIMS:We claim:

1. An automatically operated dual-fuel gas train of paint baking oven burners, wherein the gas train comprises:

• a duel-fuel burner connected to a plurality of fuel supply lines and air hoses;
• at least two air-hoses supplying air for burning selected fuel;
• at least two fuels for selection therebetween; the fuels being supplied via fuel supply lines fitted with a respective control valves to control the fuel supply;
• a plurality of micro switches installed on the air selection port for connecting the air selection port to the air hoses;
• a fuel selection valve for selecting the fuel to be burned for operating the paint baking oven; the valve connected to the dual fuel burner via interchangeably fuel supply control valves;
• a control panel electrically connected to the air selection port, fuel selection valve and the fuel control valves;

wherein the control panel is programmed to control the dual-fuel burner operation.

2. Dual-fuel gas train as claimed in claim 1, wherein the control panel comprises:

• a burner controller;
• a microprocessor;
• a fuel-selection switch for selecting a first fuel or a second fuel for burner operation;

wherein the burner controller is electrically connected to the fuel selection valve and the fuel selection valve is connected to the dual-fuel burner by means of a respective fuel line connected via fuel supply control valve for supplying the automatically selected fuel.

3. Dual-fuel gas train as claimed in claim 1 or 2, wherein the control panel comprises a burner controller, a microprocessor and a fuel-selection switch for selecting one of the two fuels to be supplied via fuel-selection valve and the microcontroller is a Programmable Logic Controller (PLC).

4. Dual-fuel gas train as claimed in claim 1, wherein at least a pair of micro-switches each is provided on a respective air hose connected to the air selection port.

5. Dual-fuel gas train as claimed in claim 1, wherein at least a micro-switch each is provided on the respective air hose connected to air selection port.

6. Dual-fuel gas train as claimed in claim 4, wherein a T-shaped clamp is provided for clamping a respective air-hose at either end thereof to prevent an inadvertent interchange of the air-hoses.

7. Dual-fuel gas train as claimed in claim 6, wherein the T-shaped clamp is slidable between a first position and a second position thereof to prevent inadvertent interchange of the air hoses.

8. Dual-fuel gas train as claimed in claim 1, wherein the fuels are Liquefied Petroleum Gas (LPG) and Liquefied Natural Gas (LNG).

9. A method for electronically operating a dual-fuel gas train of paint baking oven burners as claimed in anyone of the claims 1 to 8, wherein the method comprises the following steps:

• selection of a fuel by means of the fuel selection switch;
• connection of the air-hoses to a respective air hose to the dual-fuel burner by closing the levers of two micro switches and opening the levers of the other two micro switches;
• supplying the electrical signals of the micro switches to the programmer logic controller (PLC) of the control panel;

wherein the burner sequence is started only after receipt of the confirmation of correct fuel selection at the fuel-selection valve.

10. Method as claimed in claim 9, wherein a bracket or T-shaped metal clamp is installed between the two air-hoses for clamping a respective air hose; the bracket or T-shaped metal clamp slid between a first position and a second position thereof to select the targeted air hose connection and thereby to prevent an inadvertent interchange of the air hoses.

Dated: this day of 31st August, SANJAY KESHARWANI
APPLICANT’S PATENT AGENT