CA2900789A1 - Methods for rock flaming - Google Patents

Abstract

A method for flaming a slab having a length and a width is disclosed by passing at least two burners across the slab in a direction perpendicular to a flame emanating from each of the at least two burners from a first side of the slab to an opposite side of the slab, thereby producing a path of treated slab having a defined width; stopping the at least two burners when they reach the opposite side of the slab; indexing the at least two burners along a length of the slab by at least a distance two times the defined width; and passing the at least two burners across the slab in a direction perpendicular to a flame emanating from the at least two burners from the opposite side of the slab to the first side of the slab, thereby producing a path of treated slab having a defined width.

Description

PATENT
Atty. Dkt. P15A015 METHODS FOR ROCK FLAMING
BACKGROUND OF THE INVENTION
[0001] The present invention relates to methods for flaming natural or artificial stone. The process of flaming of natural or artificial stone has been used for decades. The purpose of the flaming is to restore a natural look on the smooth cut surface of a slab of stone. In current state of the art flaming processes, the surface of the stone is heated up locally by means of a fuel-gas-oxygen mixture.
The local heat deposition leads to a local temperature rise and local expansion stress by which small chips of stone pop off of the surface. Control of the local heat input is critical and in order to avoid breaking the rock due to too much heat input, water is often used as a cooling aid. While the process is often performed manually with a single burner moved across the material in random motion, it has also been automated.

[0002] For example, multiple smaller burners are aligned side by side of each other. These ribbon burners often cover the entire width of the slab of stone.

The burners are either pulled backward in the opposite direction of the flame along the stone or the stone is pushed on a conveyer underneath the burner in the flame direction. Typically for example, the slab of stone is conveyed from the right to the left through the flames of a stationary ribbon burner where small burners are placed next to each other. The problem that is often faced is that some materials cannot handle so much heat input.

[0003] Material that is more sensitive and cannot take the heat of multiple burner flames has been flamed with a single burner setup where one burner is moved perpendicular to the flame back and forth across the slab of stone. The slab itself indexes towards the left for example each time the burner has crossed the slab.

PATENT
Atty. Dkt. P15A015

[0004] This process though is inherently slow and therefore a small burner bundle of 2 to 3 burners positioned immediately next to each other has been used and moved in a similar fashion across the slab of stone. This process will concentrate more heat in one area and in addition has the technical problem that the leading burner works on "fresh" material while the following burner works on material that has already been treated by the first burner thereby reducing overall efficiency.

[0005] The methods of the present invention aim at increasing productivity by replacing the fuel oxygen combustion with acetylene air combustion in combination with multiple burners that are positioned apart from each other in a way that each burner treats fresh material.

[0006] Using the high flame temperature and flame propagation of the acetylene flame creates a high heat flux into the material, which requires a faster movement of the burner, thus increasing speed of operation. Air is suggested for the combustion instead of state of the art oxygen because it produces a slightly cooler flame avoiding overheating. Furthermore, it is suggested to run the combustion with a surplus of air preferably a fuel/air ratio between 1:9.6 to 1:18.
Air surplus will be a means to control heat input and width of the treated path.

[0007] To further increase productivity the use of two or more burners is suggested in a way that they are placed behind each other while preferably having an adjustable gap between the burners in order to not locate heat in close proximity. Moving these burners in a perpendicular manner across the slab will leave untreated areas which have to be processed using more advanced path geometries. Taken together these measures will provide the potential for increased productivity while at the same time avoiding a too localized heat input which could damage the material.

PATENT
Atty. Dkt. P15A015 SUMMARY OF THE INVENTION

[0008] In a first embodiment of the invention, there is disclosed a method for flaming a slab having a length and a width comprising the steps:
a) Passing at least two burners, preferably designed for acetylene air combustion, across the slab in a direction perpendicular to a flame emanating from each of the at least two burners from a first side of the slab to an opposite side of the slab, wherein a first of the at least two burners is positioned ahead of a second of the at least two burners lengthwise along the slab and wherein the flame contacts the slab thereby producing a path of treated slab having a defined width;
b) Stopping the at least two burners when they reach the opposite side of the slab;
c) Indexing the at least two burners along a length of the slab by at least a distance two times the defined width; and d) Passing the at least two burners across the slab in a direction perpendicular to a flame emanating from the at least two burners from the opposite side of the slab to the first side of the slab, wherein the flame contacts the slab thereby producing a path of treated slab having a defined width.

[0009] As noted above, the at least two burners are positioned such that when viewed along the side of the slab that the first burner is ahead of the second burner lengthwise along the slab. The two burners when passed across the slab will each emanate a flame that treats a unique portion of the slab with the defined width w so that the two burners working in conjunction will create a PATENT
Atty. Dkt. P15A015 treated path with the combined width, 2w, across the slab. The actual value for "w" will vary according to the length of the flame emanating from the at least two burners. The length of the flame can be controlled to some degree with by varying the amount of air fed into the burner. The preferred fuel/air ratio should be between 1:9.6 to 1:18.

[0010] When the at least two burners reach the opposite side of the slab, the mechanism by which the at least two burners are moved is stopped. The at least two burners will be indexed along the length of the slab in the direction of untreated slab by an amount equal to two times the defined width. Once secured, the at least two burners will be passed across the slab from the opposite side to the first side of the slab where the mechanism will be stopped and the at least two burners indexed along the length of the untreated portion of the slab by a distance two time the defined width.

[0011] The at least two burners can be at least two burners but can be more if the material can handle the increased heat input without cracking or suffering other damage. A number of x burners working in conjunction will create a treated path with the combined width of xw. Preferably the number of burners ranges from two to six.

[0012] So for example if four burners are present, they are indexed by an amount equal to four times the defined width or in case of 6 burners they indexed six times the defined width.

[0013] The at least two burners can be passed across the slab by any conventional means and the at least two burners are passed across the slab so that the flame contacts the slab for a time sufficient to treat the slab material.
The defined width is essentially the length of slab material that the flame contacts and treats and therefore can be controlled by the operator by PATENT
Atty. Dkt. P15A015 appropriate adjustments to the flame jet, air and fuel mixture as well as the burner position, angle to and distance from the surface of the slab.

[0014]
The width of the treated path is essentially the combined length of slab material that the flames of at least two burners contact and treat.

[0015] The process of passing at least two burners across the width of the slab repeats until all the treated paths cover the length of the slab with flame.

[0016] The flame will emanate from the at least two burners in a direction that is parallel to the length of the slab while the at least two burners are passed across the slab perpendicular to the direction of the flame.

[0017] Preferably, the burners are positioned such that they overlap slightly in terms of the slab surface being contacted by flame so that complete coverage of the slab can be achieved.

[0018] Preferably, the fuel is acetylene which is combusted in air.

[0019] In another embodiment of the invention, the burners are positioned differently to accommodate a slab material that is more sensitive to local heat input. In this embodiment, the at least two burners are positioned as above but a gap exists lengthwise between the first burner and the second burner. As such, each of the first and the second burner will move across the slab and produce a treated path with a defined width "w" which will be essentially the length of slab material that the flame contacts and the space between the first and the second burners will also be the width "w". After the at least two burners are passed across the slab to the opposite side of the slab, they will be stopped and indexed along the length of the slab by 4w and will be passed across the slab from the opposite side to the first side of the slab. This will result in untreated areas which are dealt with when the at least two burners reach the end of the slab. The first PATENT
Atty. Dkt. P15A015 and the second burners will be reversed and they will advance along the length of the slab in the opposite direction from the first passes across the slab by the at least two burners.

[0020] In this second embodiment of the invention, there is disclosed a method for flaming a slab having a length and a width comprising the steps:
a) Passing at least two burners, preferably designed for acetylene air combustion, across the slab in a direction perpendicular to a flame emanating from the at least two burners from a first side of the slab to an opposite side of the slab wherein a gap exists between a first burner and a second burner along the length of the slab, wherein the flame contacts the slab thereby producing a path of treated slab having a defined width;
b) Stopping the at least two burners when they reach the opposite side of the slab;
c) Indexing the at least two burners along a length of the slab by at least a distance four times the defined width; and d) Passing the at least two burners across the slab in a direction perpendicular to a flame emanating from the at least two burners from the opposite side of the slab to the first side of the slab, wherein the flame contacts the slab thereby producing a path of treated slab having a defined width.

[0021] In another third embodiment of the invention, the at least two burners are not mounted behind each other in fixed position to each other. In this embodiment, the at least two burners are mounted on separate parallel rails that will move them across the width of the slab. This arrangement can be mounted on a gantry type machine driven by rack and pinion means.

PATENT
Atty. Dkt. P15A015

[0022] The first burner assembly will pass from a first side of the slab to the opposite side of the slab with a flame emanating perpendicular to its path across the slab. This first burner assembly will create a treated path having a width "w"
based on the length of the flame. This first burner assembly will act as a master assembly as the second burner assembly will not be driven by the rack and pinion means and will literally be dragged along behind the positioning of the master assembly. This second or slave assembly will follow the master assembly at a predefined distance regardless of the operating direction of the master assembly along the length of the slab.

[0023] In this embodiment of the invention, there is disclosed a method for flaming a slab having a length and a width comprising the steps:
a) Attaching a second burner to a first burner, both preferably designed for acetylene air combustion, such that the second burner can change relative position to the first burner and travel a fixed, predefined distance behind the first burner across the width of the slab;
b) Passing a first burner across the slab in a direction perpendicular to a flame emanating from the first burner from a first side of the slab to an opposite side of the slap, wherein the flame contacts the slab thereby producing a path of treated slab having a defined width w;
C) Stopping the first burner after the second burner has crossed to the opposite side of the slab;
d) Indexing both the first and the second burners along the length of the slab by a predetermined distance;

PATENT
Atty. Dkt. P15A015 e) Passing the first burner and the second burner back across the slab in a direction perpendicular to a flame emanating from the first burner from the opposing side to the first side of the slab, wherein the flame contacts the slab thereby producing a path of treated slab having a defined width.

[0024] The relative movement between the at least two burners can also be forced and actively controlled by the appropriate mechanical, pneumatic or hydraulic means.

[0025] A number of burners above two may be employed and when this is the situation, the operator can use different movement programming techniques to ensure that the appropriate burner movement is achieved to efficiently provide flame treatment to the slab.

[0026] The burners are angled at about 20 degrees to 90 degrees from the surface of the slab that is being treated. These angles do not have to be all the same for every burner and it may be desirable to utilize a setup where the second burner behind the first burner is at a slightly smaller angle to assist in the flames and treated paths overlapping and blending in.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a schematic showing the sideways view of the prior art ribbon burner assembly and the slab moving under the burner assembly.
Figure 2 is a schematic showing the topview of a prior art ribbon burner assembly and the slab moving under the burner assembly.
Figure 3 is a schematic showing the sideways view and the topview of a prior art A

PATENT
Atty. Dkt. P15A015 single burner and its motion across the slab.
Figure 4 is a schematic showing the sideways view and the topview of a prior art burner bundle and its motion across the slab.
Figure 5 is a sideways view of the first embodiment of the invention showing the positioning of the burners relative to the slab.
Figure 6 is a topview of the first embodiment of the invention showing two burner assemblies and their paths across a slab.
Figure 7 is a sideways view of a different embodiment of the invention showing the positioning of the burners and the gap between them relative to the slab.
Figure 8 is a topview schematic of a different embodiment of the invention showing two burner assemblies and the relative gap between them and their paths across a slab.
Figure 9 is a schematic topview of another different embodiment of the invention showing the master-slave relationship between two burner assemblies and their paths across a slab.
DETAILED DESCRIPTION OF THE INVENTION

[0027] Turning to the Figures, a prior art burner assembly is shown in Figures 1 and 2. In Figure 1, the slab A is shown from the side while the burner B is shown relative to the slab A. A slab of material that is to be treated by burning A
is fed underneath an array of burners B which will provide the treatment flame is shown in Figure 2.

[0028] Alternatively, prior art rock flaming was also accomplished as shown in Figures 3 and 4.

PATENT
Atty. Dkt. P15A015

[0029] As shown in Figure 3, a single burner 1A moved across the slab C as indicated by the directional arrows.

[0030] Figure 4 depicts a similar prior art process wherein two burners 1B
are shown with their relative motions over the slab C indicated by the directional arrows. Like the single burner depicted in Figure 3, the two burners 1B
depicted in Figure 4 after the burners have crossed the slab C from left to right, they are indexed lengthwise along the slab C in the direction indicated by the directional arrows.

[0031] Figures 5 and 6 show one embodiment of the invention. In Figure 5, the slab D is shown via a sideways view with the two burners 2A and 2B shown positioned above the slab D.

[0032] In Figure 6, a slab D is shown. The slab D may be mounted by any mounting device typically used in rock flaming operations. The slab D is mounted so that it is stationary while the at least two burner assemblies 2A
and 2B move over the surface of the slab D.

[0033] The at least two burners will be positioned such that burner 2A is mounted forward of burner 2B along the length of the slab D. Each of the burners 2A and 2B will direct a flame perpendicular to the path of the two burners and having a length that is equal to a distance "w" along the length of the slab D. As the at least two burners 2A and 2B are passed over the surface of the slab D beginning at a first side of the slab D across to the opposite side of the slab D, the flames from burners 2A and 2B will contact two times the flame length or "2w" along the length of the slab D. This length "w" can be any distance that the flame will typically be directed from a burner but is typically the length of slab material that the flame contacts and treats PATENT
Atty. Dkt. P15A015

[0034] When the at least two burners 2A and 2B have reached the opposite side of the slab D, the mechanism by which they are passed across the slab D
is stopped. The mechanism is then indexed back along the length of the slab D a distance equal to 2w from where the two burners stopped. The at least two burners 2A and 2B will then be directed back across the table passing from the opposite side of the slab D to the first side of the slab D. Once they reach the first side of the slab D they are stopped and indexed back along the untreated portion of the slab a distance of "2w". This pattern is repeated until the entire length of the slab D has been treated by the burners. As shown on Figure 6, burner 2A will pass along line 10 while burner B will pass along line 10B.
After indexing along the untreated length of the slab, burner 2A will follow line 20 and burner 2B will follow path 20B. After again being indexed along the length of the untreated slab D, burner 2A will follow line 30 and burner 2B will follow line 30B.

[0035] Figures 7 and 8 show a different embodiment of the invention described with respect to Figure 6.

[0036] Figure 7 is a sideways representation of the slab D and the burners and 3B positioned above the slab D. Here the gap between the two burners is pronounced and can be seen to be a multiple of the defined width w.

[0037] In Figure 8, the at least two burners, 3A and 3B are positioned differently along the length of slab D. Whereas in Figure 6, the first burner and the second burner are positioned such that when passed over the surface of the slab, they provide a path with a combined width of 2w, in Figure 8 there is a larger gap between the first burner 3A and the second burner 3B.

[0038] The first burner 3A is positioned ahead of second burner 3B along the length of the slab D. The first burner 3A when directed across the slab D will PATENT
Atty. Dkt. P15A015 emit a flame that is a distance "w" along the slab D. Burner 3B is positioned behind burner 3A and will also emit a flame that is a distance "w' along the length of the slab D. The two burners however are positioned such that there is a distance "2w" between the burners when viewed from the side as shown in Figure 7. So when the two burners 3A and 3B are passed across the slab D
from a first side of the slab to the opposite side of the slab, together they will flame treat a distance "2w" along the length of the slab. However, they leave an opening between the passes of each of the two burners of a width equal to "w".

When the at least two burners arrive at the opposite side of the slab D, they will stop and their assembly will be indexed a distance "4w" from the position of the second burner 3B along the untreated length of the slab D and the at least two burners will be passed over the slab D from the opposite side to the first side of the slab D.

[0039] This pattern will repeat along the untreated length of the slab D
until the burner assembly reaches the end of the untreated slab D. The assembly will then be reversed in the manner that burner 3A will be behind burner 3B as the burner assembly traverses along the untreated portions of slab D in the opposite direction.

[0040] This progression could follow the pattern shown in Figure 8. First burner 3A will follow path 40 across slab D while burner 3B is following path across the slab. When they reach the opposite side of the slab D they are indexed a distance of "4w" from their initial position along the slab D and will cross from the opposite side of the slab D to the first side of the slab D
along paths 60 and 60B respectively. The burners will then stop at the first side of the burner D and be indexed another 4w along the length of untreated slab D. The at least two burners will cross along paths 80 and 80B from the first side of the slab to the opposite side of the slab D. When they reach the opposite side of the slab D the burner assembly again stops and is indexed a distance of 4w along PATENT
Atty. Dkt. P15A015 the untreated slab D. The burners 3A and 3B for purposes of this example will cross again to the first side of slab D along lines 100 and 100B respectively where they will stop.

[0041] The burners 3A and 3B will then begin advance along the length of the slab D in the opposite direction thereby to cover the areas that were not treated by the initial passes described above. So burner 3A will first pass from the first side of slab D to the opposite side of slab D along line 90 while burner 3B
simultaneously is directed along line 90B. They stop once they reach this opposite side of the slab D and are indexed further along the slab D a distance "4w" from where they stopped and will be directed across the slab D from the opposite side to the first side along paths 70 and 70B respectively. This pattern is repeated such that the burners 3A and 3B will make two more successive passes along lines 50 and 50B and lines 30 and 30B to complete flame burning coverage of the slab D.

[0042] In Figure 9, the first burner 4A and the second burner 4B are not rigidly connected so that they not always move in synchronicity with each other.
Instead the master burner 4A will move rigidly across the slab D along a prescribed path mounted on a burner assembly with is powered by the machine controller. It will pull the slave burner 4B which is mounted on a separate burner assembly that is not driven by the machine control.

[0043] The burners 4A and 4B are positioned along the first side of the slab D
and will be directed across the slab to the opposite side along paths 200 and 200B respectively. Each burner will direct a flame a distance "w" along the length of the slab D. When the at least two burners arrive at the opposite side of the slab D, the burner assembly mechanism for burner 4A (the master burner) will stop and be indexed along the untreated length of the slab D a distance of "2w". The process will then continue with the burner 4A being directed across PATENT
Atty. Dkt. P15A015 the width of the slab D until it reaches the first side along path 210. As shown in Figure 9, burner 4A will contact burner 4B at some point along the width of the slab D and physically drag burner 4B across the slab to also arrive at the first side of the slab along path 210B.

[0044] This pattern will continue with the master burner 4A following the iteration along pass across, stop and be indexed along the untreated portion of the slab D a length of 2w according to paths 230, 240, 250 and 260. Likewise the slave burner 4B will be dragged across the slab D in the direction burner is being directed along paths 230B, 240B, 250B and 260B thereby ensuring that the length of the slab D is flame treated by both the master burner 4A and slave burner 4B.

[0045] While this invention has been described with respect to particular embodiments thereof, it is apparent that numerous other forms and modifications of the invention will be obvious to those skilled in the art. The appended claims in this invention generally should be construed to cover all such obvious forms and modifications which are within the true spirit and scope of the invention.

Claims (35)

Having thus described the invention, what we claim is:

1. A method for flaming a slab having a length and a width comprising the steps:
a) Passing at least two burners across the slab in a direction perpendicular to a flame emanating from each of the at least two burners from a first side of the slab to an opposite side of the slab, wherein a first of the at least two burners is positioned ahead of a second of the at least two burners lengthwise along the slab and wherein the flame contacts the slab thereby producing a path of treated slab having a defined width;
b) Stopping the at least two burners when they reach the opposite side of the slab;
c) Indexing the at least two burners along a length of the slab by at least a distance two times the defined width; and d) Passing the at least two burners across the slab in a direction perpendicular to a flame emanating from the at least two burners from the .
opposite side of the slab to the first side of the slab, wherein the flame contacts the slab thereby producing a path of treated slab having a defined width.

2. The method as claimed in claim 1 wherein the at least two burners are two burners.

3. The method as claimed in claim 1 wherein the width of the treated path is the combined length of slab material that the flames of at least two burners contact and treat.

4. The method as claimed in claim 1 wherein steps a) to d) are repeated as necessary to treat the entire surface of the slab.

5. The method as claimed in claim 1 wherein the at least two burners are two to six burners.

6. The method as claimed in claim 1 wherein the flame contacts the slab for a time sufficient to treat the slab.

7. The method as claimed in claim 1 wherein the flames emanating from the at least two burners overlap.

8. The method as claimed in claim 1 wherein the at least two burners are indexed by an amount equal to the number of burners present.

9. The method as claimed in claim 1 wherein the slab is stationary.

10. The method as claimed in claim 1 wherein the flame is produced combusting acetylene in air.

11. The method as claimed in claim 10 wherein the ratio of acetylene to air is in the range of 1:9.6 to 1:18.

12. A method for flaming a slab having a length and a width comprising the steps:
a) Passing at least two burners across the slab in a direction perpendicular to a flame emanating from the at least two burners from a first side of the slab to an opposite side of the slab wherein a gap exists between a first burner and a second burner along the length of the slab, wherein the flame contacts the slab thereby producing a path of treated slab having a defined width;
b) Stopping the at least two burners when they reach the opposite side of the slab;
c) Indexing the at least two burners along a length of the slab by at least a distance four times the defined width; and d) Passing the at least two burners across the slab in a direction perpendicular to a flame emanating from the at least two burners from the opposite side of the slab to the first side of the slab, wherein the flame contacts the slab thereby producing a path of treated slab having a defined width.

13. The method as claimed in claim 12 wherein steps a) to d) are performed in the opposite direction along the slab when the end of the slab is reached.

14. The method as claimed in claim 12 wherein the distance between the at least two burners is equal to the defined width.

15. The method as claimed in claim 12 wherein the at least two burners are two burners.

16. The method as claimed in claim 12 wherein the defined width is equal to the length of slab material that the flame contacts and treats.

17. The method as claimed in claim 12 wherein the at least two burners are two to six burners.

18. The method as claimed in claim 12 wherein the flame contacts the slab for a time sufficient to treat the slab.

19. The method as claimed in claim 12 wherein the flames emanating from the at least two burners overlap.

20. The method as claimed in claim 12 wherein the at least two burners are indexed by an amount equal to four times the number of burners present.

21. The method as claimed in claim 12 wherein the slab is stationary.

22. The method as claimed in claim 12 wherein the flame is produced by combusting acetylene in air.

23. The method as claimed in claim 22 wherein the ratio of acetylene to air is in the range of 1:9.6 to 1:18.

24. A method for flaming a slab having a length and a width comprising the steps:
a) Attaching a second burner to a first burner such that the second burner can change relative position to the first burner and travel a fixed, predefined distance behind the first burner across the width of the slab;
b) Passing a first burner across the slab in a direction perpendicular to a flame emanating from the first burner from a first side of the slab to an opposite side of the slap, wherein the flame contacts the slab thereby producing a path of treated slab having a defined width w;
c) Stopping the first burner after the second burner has crossed to the opposite side of the slab;

d) Indexing both the first and the second burners along the length of the slab by a predetermined distance;
e) Passing the first burner and the second burner back across the slab in a direction perpendicular to a flame emanating from the first burner from the opposing side to the first side of the slab, wherein the flame contacts the slab thereby producing a path of treated slab having a defined width.

25. The method as claimed in claim 24 wherein the second burner moves independently of the first burner.

26. The method as claimed in claim 22 wherein the first burner will contact the second burner thereby causing the second burner to follow across the surface of the slab.

27. The method as claimed in claim 24 wherein the at least two burners are two burners.

28. The method as claimed in claim 24 wherein the defined width is equal to the length of the flame emanating from the at least two burners.

29. The method as claimed in claim 24 wherein the at least two burners are two to six burners.

30. The method as claimed in claim 24 wherein the flame contacts the slab for a time sufficient to treat the slab.

31. The method as claimed in claim 24 wherein the flames emanating from the at least two burners overlap.

32. The method as claimed in claim 24 wherein the at least two burners are indexed by an amount equal to two times the number of burners present.

33. The method as claimed in claim 24 wherein the slab is stationary.

34. The method as claimed in claim 24 wherein the flame is produced by combusting acetylene in air.

35. The method as claimed in claim 34 wherein the ratio of acetylene to air is in the range of 1:9.6 to 1:18.